Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

16 files changed, 10196 insertions, 0 deletions

diff --git a/fs/ecryptfs/Kconfig b/fs/ecryptfs/Kconfig
new file mode 100644
index 000000000..1bdeaa6d5
--- /dev/null
+++ b/fs/ecryptfs/Kconfig
@@ -0,0 +1,23 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config ECRYPT_FS
+	tristate "eCrypt filesystem layer support"
+	depends on KEYS && CRYPTO && (ENCRYPTED_KEYS || ENCRYPTED_KEYS=n)
+	select CRYPTO_ECB
+	select CRYPTO_CBC
+	select CRYPTO_MD5
+	help
+	  Encrypted filesystem that operates on the VFS layer.  See
+	  <file:Documentation/filesystems/ecryptfs.rst> to learn more about
+	  eCryptfs.  Userspace components are required and can be
+	  obtained from <http://ecryptfs.sf.net>.
+
+	  To compile this file system support as a module, choose M here: the
+	  module will be called ecryptfs.
+
+config ECRYPT_FS_MESSAGING
+	bool "Enable notifications for userspace key wrap/unwrap"
+	depends on ECRYPT_FS
+	help
+	  Enables the /dev/ecryptfs entry for use by ecryptfsd. This allows
+	  for userspace to wrap/unwrap file encryption keys by other
+	  backends, like OpenSSL.
diff --git a/fs/ecryptfs/Makefile b/fs/ecryptfs/Makefile
new file mode 100644
index 000000000..4f2cc5b25
--- /dev/null
+++ b/fs/ecryptfs/Makefile
@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Makefile for the Linux eCryptfs
+#
+
+obj-$(CONFIG_ECRYPT_FS) += ecryptfs.o
+
+ecryptfs-y := dentry.o file.o inode.o main.o super.o mmap.o read_write.o \
+	      crypto.o keystore.o kthread.o debug.o
+
+ecryptfs-$(CONFIG_ECRYPT_FS_MESSAGING) += messaging.o miscdev.o
diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
new file mode 100644
index 000000000..03bd55069
--- /dev/null
+++ b/fs/ecryptfs/crypto.c
@@ -0,0 +1,2084 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 1997-2004 Erez Zadok
+ * Copyright (C) 2001-2004 Stony Brook University
+ * Copyright (C) 2004-2007 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
+ *   		Michael C. Thompson <mcthomps@us.ibm.com>
+ */
+
+#include <crypto/hash.h>
+#include <crypto/skcipher.h>
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/pagemap.h>
+#include <linux/random.h>
+#include <linux/compiler.h>
+#include <linux/key.h>
+#include <linux/namei.h>
+#include <linux/file.h>
+#include <linux/scatterlist.h>
+#include <linux/slab.h>
+#include <asm/unaligned.h>
+#include <linux/kernel.h>
+#include <linux/xattr.h>
+#include "ecryptfs_kernel.h"
+
+#define DECRYPT		0
+#define ENCRYPT		1
+
+/**
+ * ecryptfs_from_hex
+ * @dst: Buffer to take the bytes from src hex; must be at least of
+ *       size (src_size / 2)
+ * @src: Buffer to be converted from a hex string representation to raw value
+ * @dst_size: size of dst buffer, or number of hex characters pairs to convert
+ */
+void ecryptfs_from_hex(char *dst, char *src, int dst_size)
+{
+	int x;
+	char tmp[3] = { 0, };
+
+	for (x = 0; x < dst_size; x++) {
+		tmp[0] = src[x * 2];
+		tmp[1] = src[x * 2 + 1];
+		dst[x] = (unsigned char)simple_strtol(tmp, NULL, 16);
+	}
+}
+
+/**
+ * ecryptfs_calculate_md5 - calculates the md5 of @src
+ * @dst: Pointer to 16 bytes of allocated memory
+ * @crypt_stat: Pointer to crypt_stat struct for the current inode
+ * @src: Data to be md5'd
+ * @len: Length of @src
+ *
+ * Uses the allocated crypto context that crypt_stat references to
+ * generate the MD5 sum of the contents of src.
+ */
+static int ecryptfs_calculate_md5(char *dst,
+				  struct ecryptfs_crypt_stat *crypt_stat,
+				  char *src, int len)
+{
+	int rc = crypto_shash_tfm_digest(crypt_stat->hash_tfm, src, len, dst);
+
+	if (rc) {
+		printk(KERN_ERR
+		       "%s: Error computing crypto hash; rc = [%d]\n",
+		       __func__, rc);
+		goto out;
+	}
+out:
+	return rc;
+}
+
+static int ecryptfs_crypto_api_algify_cipher_name(char **algified_name,
+						  char *cipher_name,
+						  char *chaining_modifier)
+{
+	int cipher_name_len = strlen(cipher_name);
+	int chaining_modifier_len = strlen(chaining_modifier);
+	int algified_name_len;
+	int rc;
+
+	algified_name_len = (chaining_modifier_len + cipher_name_len + 3);
+	(*algified_name) = kmalloc(algified_name_len, GFP_KERNEL);
+	if (!(*algified_name)) {
+		rc = -ENOMEM;
+		goto out;
+	}
+	snprintf((*algified_name), algified_name_len, "%s(%s)",
+		 chaining_modifier, cipher_name);
+	rc = 0;
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_derive_iv
+ * @iv: destination for the derived iv vale
+ * @crypt_stat: Pointer to crypt_stat struct for the current inode
+ * @offset: Offset of the extent whose IV we are to derive
+ *
+ * Generate the initialization vector from the given root IV and page
+ * offset.
+ *
+ * Returns zero on success; non-zero on error.
+ */
+int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
+		       loff_t offset)
+{
+	int rc = 0;
+	char dst[MD5_DIGEST_SIZE];
+	char src[ECRYPTFS_MAX_IV_BYTES + 16];
+
+	if (unlikely(ecryptfs_verbosity > 0)) {
+		ecryptfs_printk(KERN_DEBUG, "root iv:\n");
+		ecryptfs_dump_hex(crypt_stat->root_iv, crypt_stat->iv_bytes);
+	}
+	/* TODO: It is probably secure to just cast the least
+	 * significant bits of the root IV into an unsigned long and
+	 * add the offset to that rather than go through all this
+	 * hashing business. -Halcrow */
+	memcpy(src, crypt_stat->root_iv, crypt_stat->iv_bytes);
+	memset((src + crypt_stat->iv_bytes), 0, 16);
+	snprintf((src + crypt_stat->iv_bytes), 16, "%lld", offset);
+	if (unlikely(ecryptfs_verbosity > 0)) {
+		ecryptfs_printk(KERN_DEBUG, "source:\n");
+		ecryptfs_dump_hex(src, (crypt_stat->iv_bytes + 16));
+	}
+	rc = ecryptfs_calculate_md5(dst, crypt_stat, src,
+				    (crypt_stat->iv_bytes + 16));
+	if (rc) {
+		ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
+				"MD5 while generating IV for a page\n");
+		goto out;
+	}
+	memcpy(iv, dst, crypt_stat->iv_bytes);
+	if (unlikely(ecryptfs_verbosity > 0)) {
+		ecryptfs_printk(KERN_DEBUG, "derived iv:\n");
+		ecryptfs_dump_hex(iv, crypt_stat->iv_bytes);
+	}
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_init_crypt_stat
+ * @crypt_stat: Pointer to the crypt_stat struct to initialize.
+ *
+ * Initialize the crypt_stat structure.
+ */
+int ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
+{
+	struct crypto_shash *tfm;
+	int rc;
+
+	tfm = crypto_alloc_shash(ECRYPTFS_DEFAULT_HASH, 0, 0);
+	if (IS_ERR(tfm)) {
+		rc = PTR_ERR(tfm);
+		ecryptfs_printk(KERN_ERR, "Error attempting to "
+				"allocate crypto context; rc = [%d]\n",
+				rc);
+		return rc;
+	}
+
+	memset((void *)crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
+	INIT_LIST_HEAD(&crypt_stat->keysig_list);
+	mutex_init(&crypt_stat->keysig_list_mutex);
+	mutex_init(&crypt_stat->cs_mutex);
+	mutex_init(&crypt_stat->cs_tfm_mutex);
+	crypt_stat->hash_tfm = tfm;
+	crypt_stat->flags |= ECRYPTFS_STRUCT_INITIALIZED;
+
+	return 0;
+}
+
+/**
+ * ecryptfs_destroy_crypt_stat
+ * @crypt_stat: Pointer to the crypt_stat struct to initialize.
+ *
+ * Releases all memory associated with a crypt_stat struct.
+ */
+void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat)
+{
+	struct ecryptfs_key_sig *key_sig, *key_sig_tmp;
+
+	crypto_free_skcipher(crypt_stat->tfm);
+	crypto_free_shash(crypt_stat->hash_tfm);
+	list_for_each_entry_safe(key_sig, key_sig_tmp,
+				 &crypt_stat->keysig_list, crypt_stat_list) {
+		list_del(&key_sig->crypt_stat_list);
+		kmem_cache_free(ecryptfs_key_sig_cache, key_sig);
+	}
+	memset(crypt_stat, 0, sizeof(struct ecryptfs_crypt_stat));
+}
+
+void ecryptfs_destroy_mount_crypt_stat(
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
+{
+	struct ecryptfs_global_auth_tok *auth_tok, *auth_tok_tmp;
+
+	if (!(mount_crypt_stat->flags & ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED))
+		return;
+	mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
+	list_for_each_entry_safe(auth_tok, auth_tok_tmp,
+				 &mount_crypt_stat->global_auth_tok_list,
+				 mount_crypt_stat_list) {
+		list_del(&auth_tok->mount_crypt_stat_list);
+		if (!(auth_tok->flags & ECRYPTFS_AUTH_TOK_INVALID))
+			key_put(auth_tok->global_auth_tok_key);
+		kmem_cache_free(ecryptfs_global_auth_tok_cache, auth_tok);
+	}
+	mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
+	memset(mount_crypt_stat, 0, sizeof(struct ecryptfs_mount_crypt_stat));
+}
+
+/**
+ * virt_to_scatterlist
+ * @addr: Virtual address
+ * @size: Size of data; should be an even multiple of the block size
+ * @sg: Pointer to scatterlist array; set to NULL to obtain only
+ *      the number of scatterlist structs required in array
+ * @sg_size: Max array size
+ *
+ * Fills in a scatterlist array with page references for a passed
+ * virtual address.
+ *
+ * Returns the number of scatterlist structs in array used
+ */
+int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
+			int sg_size)
+{
+	int i = 0;
+	struct page *pg;
+	int offset;
+	int remainder_of_page;
+
+	sg_init_table(sg, sg_size);
+
+	while (size > 0 && i < sg_size) {
+		pg = virt_to_page(addr);
+		offset = offset_in_page(addr);
+		sg_set_page(&sg[i], pg, 0, offset);
+		remainder_of_page = PAGE_SIZE - offset;
+		if (size >= remainder_of_page) {
+			sg[i].length = remainder_of_page;
+			addr += remainder_of_page;
+			size -= remainder_of_page;
+		} else {
+			sg[i].length = size;
+			addr += size;
+			size = 0;
+		}
+		i++;
+	}
+	if (size > 0)
+		return -ENOMEM;
+	return i;
+}
+
+/**
+ * crypt_scatterlist
+ * @crypt_stat: Pointer to the crypt_stat struct to initialize.
+ * @dst_sg: Destination of the data after performing the crypto operation
+ * @src_sg: Data to be encrypted or decrypted
+ * @size: Length of data
+ * @iv: IV to use
+ * @op: ENCRYPT or DECRYPT to indicate the desired operation
+ *
+ * Returns the number of bytes encrypted or decrypted; negative value on error
+ */
+static int crypt_scatterlist(struct ecryptfs_crypt_stat *crypt_stat,
+			     struct scatterlist *dst_sg,
+			     struct scatterlist *src_sg, int size,
+			     unsigned char *iv, int op)
+{
+	struct skcipher_request *req = NULL;
+	DECLARE_CRYPTO_WAIT(ecr);
+	int rc = 0;
+
+	if (unlikely(ecryptfs_verbosity > 0)) {
+		ecryptfs_printk(KERN_DEBUG, "Key size [%zd]; key:\n",
+				crypt_stat->key_size);
+		ecryptfs_dump_hex(crypt_stat->key,
+				  crypt_stat->key_size);
+	}
+
+	mutex_lock(&crypt_stat->cs_tfm_mutex);
+	req = skcipher_request_alloc(crypt_stat->tfm, GFP_NOFS);
+	if (!req) {
+		mutex_unlock(&crypt_stat->cs_tfm_mutex);
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	skcipher_request_set_callback(req,
+			CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP,
+			crypto_req_done, &ecr);
+	/* Consider doing this once, when the file is opened */
+	if (!(crypt_stat->flags & ECRYPTFS_KEY_SET)) {
+		rc = crypto_skcipher_setkey(crypt_stat->tfm, crypt_stat->key,
+					    crypt_stat->key_size);
+		if (rc) {
+			ecryptfs_printk(KERN_ERR,
+					"Error setting key; rc = [%d]\n",
+					rc);
+			mutex_unlock(&crypt_stat->cs_tfm_mutex);
+			rc = -EINVAL;
+			goto out;
+		}
+		crypt_stat->flags |= ECRYPTFS_KEY_SET;
+	}
+	mutex_unlock(&crypt_stat->cs_tfm_mutex);
+	skcipher_request_set_crypt(req, src_sg, dst_sg, size, iv);
+	rc = op == ENCRYPT ? crypto_skcipher_encrypt(req) :
+			     crypto_skcipher_decrypt(req);
+	rc = crypto_wait_req(rc, &ecr);
+out:
+	skcipher_request_free(req);
+	return rc;
+}
+
+/*
+ * lower_offset_for_page
+ *
+ * Convert an eCryptfs page index into a lower byte offset
+ */
+static loff_t lower_offset_for_page(struct ecryptfs_crypt_stat *crypt_stat,
+				    struct page *page)
+{
+	return ecryptfs_lower_header_size(crypt_stat) +
+	       ((loff_t)page->index << PAGE_SHIFT);
+}
+
+/**
+ * crypt_extent
+ * @crypt_stat: crypt_stat containing cryptographic context for the
+ *              encryption operation
+ * @dst_page: The page to write the result into
+ * @src_page: The page to read from
+ * @extent_offset: Page extent offset for use in generating IV
+ * @op: ENCRYPT or DECRYPT to indicate the desired operation
+ *
+ * Encrypts or decrypts one extent of data.
+ *
+ * Return zero on success; non-zero otherwise
+ */
+static int crypt_extent(struct ecryptfs_crypt_stat *crypt_stat,
+			struct page *dst_page,
+			struct page *src_page,
+			unsigned long extent_offset, int op)
+{
+	pgoff_t page_index = op == ENCRYPT ? src_page->index : dst_page->index;
+	loff_t extent_base;
+	char extent_iv[ECRYPTFS_MAX_IV_BYTES];
+	struct scatterlist src_sg, dst_sg;
+	size_t extent_size = crypt_stat->extent_size;
+	int rc;
+
+	extent_base = (((loff_t)page_index) * (PAGE_SIZE / extent_size));
+	rc = ecryptfs_derive_iv(extent_iv, crypt_stat,
+				(extent_base + extent_offset));
+	if (rc) {
+		ecryptfs_printk(KERN_ERR, "Error attempting to derive IV for "
+			"extent [0x%.16llx]; rc = [%d]\n",
+			(unsigned long long)(extent_base + extent_offset), rc);
+		goto out;
+	}
+
+	sg_init_table(&src_sg, 1);
+	sg_init_table(&dst_sg, 1);
+
+	sg_set_page(&src_sg, src_page, extent_size,
+		    extent_offset * extent_size);
+	sg_set_page(&dst_sg, dst_page, extent_size,
+		    extent_offset * extent_size);
+
+	rc = crypt_scatterlist(crypt_stat, &dst_sg, &src_sg, extent_size,
+			       extent_iv, op);
+	if (rc < 0) {
+		printk(KERN_ERR "%s: Error attempting to crypt page with "
+		       "page_index = [%ld], extent_offset = [%ld]; "
+		       "rc = [%d]\n", __func__, page_index, extent_offset, rc);
+		goto out;
+	}
+	rc = 0;
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_encrypt_page
+ * @page: Page mapped from the eCryptfs inode for the file; contains
+ *        decrypted content that needs to be encrypted (to a temporary
+ *        page; not in place) and written out to the lower file
+ *
+ * Encrypt an eCryptfs page. This is done on a per-extent basis. Note
+ * that eCryptfs pages may straddle the lower pages -- for instance,
+ * if the file was created on a machine with an 8K page size
+ * (resulting in an 8K header), and then the file is copied onto a
+ * host with a 32K page size, then when reading page 0 of the eCryptfs
+ * file, 24K of page 0 of the lower file will be read and decrypted,
+ * and then 8K of page 1 of the lower file will be read and decrypted.
+ *
+ * Returns zero on success; negative on error
+ */
+int ecryptfs_encrypt_page(struct page *page)
+{
+	struct inode *ecryptfs_inode;
+	struct ecryptfs_crypt_stat *crypt_stat;
+	char *enc_extent_virt;
+	struct page *enc_extent_page = NULL;
+	loff_t extent_offset;
+	loff_t lower_offset;
+	int rc = 0;
+
+	ecryptfs_inode = page->mapping->host;
+	crypt_stat =
+		&(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
+	BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
+	enc_extent_page = alloc_page(GFP_USER);
+	if (!enc_extent_page) {
+		rc = -ENOMEM;
+		ecryptfs_printk(KERN_ERR, "Error allocating memory for "
+				"encrypted extent\n");
+		goto out;
+	}
+
+	for (extent_offset = 0;
+	     extent_offset < (PAGE_SIZE / crypt_stat->extent_size);
+	     extent_offset++) {
+		rc = crypt_extent(crypt_stat, enc_extent_page, page,
+				  extent_offset, ENCRYPT);
+		if (rc) {
+			printk(KERN_ERR "%s: Error encrypting extent; "
+			       "rc = [%d]\n", __func__, rc);
+			goto out;
+		}
+	}
+
+	lower_offset = lower_offset_for_page(crypt_stat, page);
+	enc_extent_virt = kmap_local_page(enc_extent_page);
+	rc = ecryptfs_write_lower(ecryptfs_inode, enc_extent_virt, lower_offset,
+				  PAGE_SIZE);
+	kunmap_local(enc_extent_virt);
+	if (rc < 0) {
+		ecryptfs_printk(KERN_ERR,
+			"Error attempting to write lower page; rc = [%d]\n",
+			rc);
+		goto out;
+	}
+	rc = 0;
+out:
+	if (enc_extent_page) {
+		__free_page(enc_extent_page);
+	}
+	return rc;
+}
+
+/**
+ * ecryptfs_decrypt_page
+ * @page: Page mapped from the eCryptfs inode for the file; data read
+ *        and decrypted from the lower file will be written into this
+ *        page
+ *
+ * Decrypt an eCryptfs page. This is done on a per-extent basis. Note
+ * that eCryptfs pages may straddle the lower pages -- for instance,
+ * if the file was created on a machine with an 8K page size
+ * (resulting in an 8K header), and then the file is copied onto a
+ * host with a 32K page size, then when reading page 0 of the eCryptfs
+ * file, 24K of page 0 of the lower file will be read and decrypted,
+ * and then 8K of page 1 of the lower file will be read and decrypted.
+ *
+ * Returns zero on success; negative on error
+ */
+int ecryptfs_decrypt_page(struct page *page)
+{
+	struct inode *ecryptfs_inode;
+	struct ecryptfs_crypt_stat *crypt_stat;
+	char *page_virt;
+	unsigned long extent_offset;
+	loff_t lower_offset;
+	int rc = 0;
+
+	ecryptfs_inode = page->mapping->host;
+	crypt_stat =
+		&(ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat);
+	BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
+
+	lower_offset = lower_offset_for_page(crypt_stat, page);
+	page_virt = kmap_local_page(page);
+	rc = ecryptfs_read_lower(page_virt, lower_offset, PAGE_SIZE,
+				 ecryptfs_inode);
+	kunmap_local(page_virt);
+	if (rc < 0) {
+		ecryptfs_printk(KERN_ERR,
+			"Error attempting to read lower page; rc = [%d]\n",
+			rc);
+		goto out;
+	}
+
+	for (extent_offset = 0;
+	     extent_offset < (PAGE_SIZE / crypt_stat->extent_size);
+	     extent_offset++) {
+		rc = crypt_extent(crypt_stat, page, page,
+				  extent_offset, DECRYPT);
+		if (rc) {
+			printk(KERN_ERR "%s: Error decrypting extent; "
+			       "rc = [%d]\n", __func__, rc);
+			goto out;
+		}
+	}
+out:
+	return rc;
+}
+
+#define ECRYPTFS_MAX_SCATTERLIST_LEN 4
+
+/**
+ * ecryptfs_init_crypt_ctx
+ * @crypt_stat: Uninitialized crypt stats structure
+ *
+ * Initialize the crypto context.
+ *
+ * TODO: Performance: Keep a cache of initialized cipher contexts;
+ * only init if needed
+ */
+int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat)
+{
+	char *full_alg_name;
+	int rc = -EINVAL;
+
+	ecryptfs_printk(KERN_DEBUG,
+			"Initializing cipher [%s]; strlen = [%d]; "
+			"key_size_bits = [%zd]\n",
+			crypt_stat->cipher, (int)strlen(crypt_stat->cipher),
+			crypt_stat->key_size << 3);
+	mutex_lock(&crypt_stat->cs_tfm_mutex);
+	if (crypt_stat->tfm) {
+		rc = 0;
+		goto out_unlock;
+	}
+	rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name,
+						    crypt_stat->cipher, "cbc");
+	if (rc)
+		goto out_unlock;
+	crypt_stat->tfm = crypto_alloc_skcipher(full_alg_name, 0, 0);
+	if (IS_ERR(crypt_stat->tfm)) {
+		rc = PTR_ERR(crypt_stat->tfm);
+		crypt_stat->tfm = NULL;
+		ecryptfs_printk(KERN_ERR, "cryptfs: init_crypt_ctx(): "
+				"Error initializing cipher [%s]\n",
+				full_alg_name);
+		goto out_free;
+	}
+	crypto_skcipher_set_flags(crypt_stat->tfm,
+				  CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
+	rc = 0;
+out_free:
+	kfree(full_alg_name);
+out_unlock:
+	mutex_unlock(&crypt_stat->cs_tfm_mutex);
+	return rc;
+}
+
+static void set_extent_mask_and_shift(struct ecryptfs_crypt_stat *crypt_stat)
+{
+	int extent_size_tmp;
+
+	crypt_stat->extent_mask = 0xFFFFFFFF;
+	crypt_stat->extent_shift = 0;
+	if (crypt_stat->extent_size == 0)
+		return;
+	extent_size_tmp = crypt_stat->extent_size;
+	while ((extent_size_tmp & 0x01) == 0) {
+		extent_size_tmp >>= 1;
+		crypt_stat->extent_mask <<= 1;
+		crypt_stat->extent_shift++;
+	}
+}
+
+void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat)
+{
+	/* Default values; may be overwritten as we are parsing the
+	 * packets. */
+	crypt_stat->extent_size = ECRYPTFS_DEFAULT_EXTENT_SIZE;
+	set_extent_mask_and_shift(crypt_stat);
+	crypt_stat->iv_bytes = ECRYPTFS_DEFAULT_IV_BYTES;
+	if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
+		crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
+	else {
+		if (PAGE_SIZE <= ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)
+			crypt_stat->metadata_size =
+				ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
+		else
+			crypt_stat->metadata_size = PAGE_SIZE;
+	}
+}
+
+/*
+ * ecryptfs_compute_root_iv
+ *
+ * On error, sets the root IV to all 0's.
+ */
+int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat)
+{
+	int rc = 0;
+	char dst[MD5_DIGEST_SIZE];
+
+	BUG_ON(crypt_stat->iv_bytes > MD5_DIGEST_SIZE);
+	BUG_ON(crypt_stat->iv_bytes <= 0);
+	if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
+		rc = -EINVAL;
+		ecryptfs_printk(KERN_WARNING, "Session key not valid; "
+				"cannot generate root IV\n");
+		goto out;
+	}
+	rc = ecryptfs_calculate_md5(dst, crypt_stat, crypt_stat->key,
+				    crypt_stat->key_size);
+	if (rc) {
+		ecryptfs_printk(KERN_WARNING, "Error attempting to compute "
+				"MD5 while generating root IV\n");
+		goto out;
+	}
+	memcpy(crypt_stat->root_iv, dst, crypt_stat->iv_bytes);
+out:
+	if (rc) {
+		memset(crypt_stat->root_iv, 0, crypt_stat->iv_bytes);
+		crypt_stat->flags |= ECRYPTFS_SECURITY_WARNING;
+	}
+	return rc;
+}
+
+static void ecryptfs_generate_new_key(struct ecryptfs_crypt_stat *crypt_stat)
+{
+	get_random_bytes(crypt_stat->key, crypt_stat->key_size);
+	crypt_stat->flags |= ECRYPTFS_KEY_VALID;
+	ecryptfs_compute_root_iv(crypt_stat);
+	if (unlikely(ecryptfs_verbosity > 0)) {
+		ecryptfs_printk(KERN_DEBUG, "Generated new session key:\n");
+		ecryptfs_dump_hex(crypt_stat->key,
+				  crypt_stat->key_size);
+	}
+}
+
+/**
+ * ecryptfs_copy_mount_wide_flags_to_inode_flags
+ * @crypt_stat: The inode's cryptographic context
+ * @mount_crypt_stat: The mount point's cryptographic context
+ *
+ * This function propagates the mount-wide flags to individual inode
+ * flags.
+ */
+static void ecryptfs_copy_mount_wide_flags_to_inode_flags(
+	struct ecryptfs_crypt_stat *crypt_stat,
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
+{
+	if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
+		crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
+	if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
+		crypt_stat->flags |= ECRYPTFS_VIEW_AS_ENCRYPTED;
+	if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
+		crypt_stat->flags |= ECRYPTFS_ENCRYPT_FILENAMES;
+		if (mount_crypt_stat->flags
+		    & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)
+			crypt_stat->flags |= ECRYPTFS_ENCFN_USE_MOUNT_FNEK;
+		else if (mount_crypt_stat->flags
+			 & ECRYPTFS_GLOBAL_ENCFN_USE_FEK)
+			crypt_stat->flags |= ECRYPTFS_ENCFN_USE_FEK;
+	}
+}
+
+static int ecryptfs_copy_mount_wide_sigs_to_inode_sigs(
+	struct ecryptfs_crypt_stat *crypt_stat,
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
+{
+	struct ecryptfs_global_auth_tok *global_auth_tok;
+	int rc = 0;
+
+	mutex_lock(&crypt_stat->keysig_list_mutex);
+	mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
+
+	list_for_each_entry(global_auth_tok,
+			    &mount_crypt_stat->global_auth_tok_list,
+			    mount_crypt_stat_list) {
+		if (global_auth_tok->flags & ECRYPTFS_AUTH_TOK_FNEK)
+			continue;
+		rc = ecryptfs_add_keysig(crypt_stat, global_auth_tok->sig);
+		if (rc) {
+			printk(KERN_ERR "Error adding keysig; rc = [%d]\n", rc);
+			goto out;
+		}
+	}
+
+out:
+	mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
+	mutex_unlock(&crypt_stat->keysig_list_mutex);
+	return rc;
+}
+
+/**
+ * ecryptfs_set_default_crypt_stat_vals
+ * @crypt_stat: The inode's cryptographic context
+ * @mount_crypt_stat: The mount point's cryptographic context
+ *
+ * Default values in the event that policy does not override them.
+ */
+static void ecryptfs_set_default_crypt_stat_vals(
+	struct ecryptfs_crypt_stat *crypt_stat,
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
+{
+	ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
+						      mount_crypt_stat);
+	ecryptfs_set_default_sizes(crypt_stat);
+	strcpy(crypt_stat->cipher, ECRYPTFS_DEFAULT_CIPHER);
+	crypt_stat->key_size = ECRYPTFS_DEFAULT_KEY_BYTES;
+	crypt_stat->flags &= ~(ECRYPTFS_KEY_VALID);
+	crypt_stat->file_version = ECRYPTFS_FILE_VERSION;
+	crypt_stat->mount_crypt_stat = mount_crypt_stat;
+}
+
+/**
+ * ecryptfs_new_file_context
+ * @ecryptfs_inode: The eCryptfs inode
+ *
+ * If the crypto context for the file has not yet been established,
+ * this is where we do that.  Establishing a new crypto context
+ * involves the following decisions:
+ *  - What cipher to use?
+ *  - What set of authentication tokens to use?
+ * Here we just worry about getting enough information into the
+ * authentication tokens so that we know that they are available.
+ * We associate the available authentication tokens with the new file
+ * via the set of signatures in the crypt_stat struct.  Later, when
+ * the headers are actually written out, we may again defer to
+ * userspace to perform the encryption of the session key; for the
+ * foreseeable future, this will be the case with public key packets.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int ecryptfs_new_file_context(struct inode *ecryptfs_inode)
+{
+	struct ecryptfs_crypt_stat *crypt_stat =
+	    &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
+	    &ecryptfs_superblock_to_private(
+		    ecryptfs_inode->i_sb)->mount_crypt_stat;
+	int cipher_name_len;
+	int rc = 0;
+
+	ecryptfs_set_default_crypt_stat_vals(crypt_stat, mount_crypt_stat);
+	crypt_stat->flags |= (ECRYPTFS_ENCRYPTED | ECRYPTFS_KEY_VALID);
+	ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
+						      mount_crypt_stat);
+	rc = ecryptfs_copy_mount_wide_sigs_to_inode_sigs(crypt_stat,
+							 mount_crypt_stat);
+	if (rc) {
+		printk(KERN_ERR "Error attempting to copy mount-wide key sigs "
+		       "to the inode key sigs; rc = [%d]\n", rc);
+		goto out;
+	}
+	cipher_name_len =
+		strlen(mount_crypt_stat->global_default_cipher_name);
+	memcpy(crypt_stat->cipher,
+	       mount_crypt_stat->global_default_cipher_name,
+	       cipher_name_len);
+	crypt_stat->cipher[cipher_name_len] = '\0';
+	crypt_stat->key_size =
+		mount_crypt_stat->global_default_cipher_key_size;
+	ecryptfs_generate_new_key(crypt_stat);
+	rc = ecryptfs_init_crypt_ctx(crypt_stat);
+	if (rc)
+		ecryptfs_printk(KERN_ERR, "Error initializing cryptographic "
+				"context for cipher [%s]: rc = [%d]\n",
+				crypt_stat->cipher, rc);
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_validate_marker - check for the ecryptfs marker
+ * @data: The data block in which to check
+ *
+ * Returns zero if marker found; -EINVAL if not found
+ */
+static int ecryptfs_validate_marker(char *data)
+{
+	u32 m_1, m_2;
+
+	m_1 = get_unaligned_be32(data);
+	m_2 = get_unaligned_be32(data + 4);
+	if ((m_1 ^ MAGIC_ECRYPTFS_MARKER) == m_2)
+		return 0;
+	ecryptfs_printk(KERN_DEBUG, "m_1 = [0x%.8x]; m_2 = [0x%.8x]; "
+			"MAGIC_ECRYPTFS_MARKER = [0x%.8x]\n", m_1, m_2,
+			MAGIC_ECRYPTFS_MARKER);
+	ecryptfs_printk(KERN_DEBUG, "(m_1 ^ MAGIC_ECRYPTFS_MARKER) = "
+			"[0x%.8x]\n", (m_1 ^ MAGIC_ECRYPTFS_MARKER));
+	return -EINVAL;
+}
+
+struct ecryptfs_flag_map_elem {
+	u32 file_flag;
+	u32 local_flag;
+};
+
+/* Add support for additional flags by adding elements here. */
+static struct ecryptfs_flag_map_elem ecryptfs_flag_map[] = {
+	{0x00000001, ECRYPTFS_ENABLE_HMAC},
+	{0x00000002, ECRYPTFS_ENCRYPTED},
+	{0x00000004, ECRYPTFS_METADATA_IN_XATTR},
+	{0x00000008, ECRYPTFS_ENCRYPT_FILENAMES}
+};
+
+/**
+ * ecryptfs_process_flags
+ * @crypt_stat: The cryptographic context
+ * @page_virt: Source data to be parsed
+ * @bytes_read: Updated with the number of bytes read
+ */
+static void ecryptfs_process_flags(struct ecryptfs_crypt_stat *crypt_stat,
+				  char *page_virt, int *bytes_read)
+{
+	int i;
+	u32 flags;
+
+	flags = get_unaligned_be32(page_virt);
+	for (i = 0; i < ARRAY_SIZE(ecryptfs_flag_map); i++)
+		if (flags & ecryptfs_flag_map[i].file_flag) {
+			crypt_stat->flags |= ecryptfs_flag_map[i].local_flag;
+		} else
+			crypt_stat->flags &= ~(ecryptfs_flag_map[i].local_flag);
+	/* Version is in top 8 bits of the 32-bit flag vector */
+	crypt_stat->file_version = ((flags >> 24) & 0xFF);
+	(*bytes_read) = 4;
+}
+
+/**
+ * write_ecryptfs_marker
+ * @page_virt: The pointer to in a page to begin writing the marker
+ * @written: Number of bytes written
+ *
+ * Marker = 0x3c81b7f5
+ */
+static void write_ecryptfs_marker(char *page_virt, size_t *written)
+{
+	u32 m_1, m_2;
+
+	get_random_bytes(&m_1, (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2));
+	m_2 = (m_1 ^ MAGIC_ECRYPTFS_MARKER);
+	put_unaligned_be32(m_1, page_virt);
+	page_virt += (MAGIC_ECRYPTFS_MARKER_SIZE_BYTES / 2);
+	put_unaligned_be32(m_2, page_virt);
+	(*written) = MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
+}
+
+void ecryptfs_write_crypt_stat_flags(char *page_virt,
+				     struct ecryptfs_crypt_stat *crypt_stat,
+				     size_t *written)
+{
+	u32 flags = 0;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(ecryptfs_flag_map); i++)
+		if (crypt_stat->flags & ecryptfs_flag_map[i].local_flag)
+			flags |= ecryptfs_flag_map[i].file_flag;
+	/* Version is in top 8 bits of the 32-bit flag vector */
+	flags |= ((((u8)crypt_stat->file_version) << 24) & 0xFF000000);
+	put_unaligned_be32(flags, page_virt);
+	(*written) = 4;
+}
+
+struct ecryptfs_cipher_code_str_map_elem {
+	char cipher_str[16];
+	u8 cipher_code;
+};
+
+/* Add support for additional ciphers by adding elements here. The
+ * cipher_code is whatever OpenPGP applications use to identify the
+ * ciphers. List in order of probability. */
+static struct ecryptfs_cipher_code_str_map_elem
+ecryptfs_cipher_code_str_map[] = {
+	{"aes",RFC2440_CIPHER_AES_128 },
+	{"blowfish", RFC2440_CIPHER_BLOWFISH},
+	{"des3_ede", RFC2440_CIPHER_DES3_EDE},
+	{"cast5", RFC2440_CIPHER_CAST_5},
+	{"twofish", RFC2440_CIPHER_TWOFISH},
+	{"cast6", RFC2440_CIPHER_CAST_6},
+	{"aes", RFC2440_CIPHER_AES_192},
+	{"aes", RFC2440_CIPHER_AES_256}
+};
+
+/**
+ * ecryptfs_code_for_cipher_string
+ * @cipher_name: The string alias for the cipher
+ * @key_bytes: Length of key in bytes; used for AES code selection
+ *
+ * Returns zero on no match, or the cipher code on match
+ */
+u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes)
+{
+	int i;
+	u8 code = 0;
+	struct ecryptfs_cipher_code_str_map_elem *map =
+		ecryptfs_cipher_code_str_map;
+
+	if (strcmp(cipher_name, "aes") == 0) {
+		switch (key_bytes) {
+		case 16:
+			code = RFC2440_CIPHER_AES_128;
+			break;
+		case 24:
+			code = RFC2440_CIPHER_AES_192;
+			break;
+		case 32:
+			code = RFC2440_CIPHER_AES_256;
+		}
+	} else {
+		for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
+			if (strcmp(cipher_name, map[i].cipher_str) == 0) {
+				code = map[i].cipher_code;
+				break;
+			}
+	}
+	return code;
+}
+
+/**
+ * ecryptfs_cipher_code_to_string
+ * @str: Destination to write out the cipher name
+ * @cipher_code: The code to convert to cipher name string
+ *
+ * Returns zero on success
+ */
+int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code)
+{
+	int rc = 0;
+	int i;
+
+	str[0] = '\0';
+	for (i = 0; i < ARRAY_SIZE(ecryptfs_cipher_code_str_map); i++)
+		if (cipher_code == ecryptfs_cipher_code_str_map[i].cipher_code)
+			strcpy(str, ecryptfs_cipher_code_str_map[i].cipher_str);
+	if (str[0] == '\0') {
+		ecryptfs_printk(KERN_WARNING, "Cipher code not recognized: "
+				"[%d]\n", cipher_code);
+		rc = -EINVAL;
+	}
+	return rc;
+}
+
+int ecryptfs_read_and_validate_header_region(struct inode *inode)
+{
+	u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
+	u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
+	int rc;
+
+	rc = ecryptfs_read_lower(file_size, 0, ECRYPTFS_SIZE_AND_MARKER_BYTES,
+				 inode);
+	if (rc < 0)
+		return rc;
+	else if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
+		return -EINVAL;
+	rc = ecryptfs_validate_marker(marker);
+	if (!rc)
+		ecryptfs_i_size_init(file_size, inode);
+	return rc;
+}
+
+void
+ecryptfs_write_header_metadata(char *virt,
+			       struct ecryptfs_crypt_stat *crypt_stat,
+			       size_t *written)
+{
+	u32 header_extent_size;
+	u16 num_header_extents_at_front;
+
+	header_extent_size = (u32)crypt_stat->extent_size;
+	num_header_extents_at_front =
+		(u16)(crypt_stat->metadata_size / crypt_stat->extent_size);
+	put_unaligned_be32(header_extent_size, virt);
+	virt += 4;
+	put_unaligned_be16(num_header_extents_at_front, virt);
+	(*written) = 6;
+}
+
+struct kmem_cache *ecryptfs_header_cache;
+
+/**
+ * ecryptfs_write_headers_virt
+ * @page_virt: The virtual address to write the headers to
+ * @max: The size of memory allocated at page_virt
+ * @size: Set to the number of bytes written by this function
+ * @crypt_stat: The cryptographic context
+ * @ecryptfs_dentry: The eCryptfs dentry
+ *
+ * Format version: 1
+ *
+ *   Header Extent:
+ *     Octets 0-7:        Unencrypted file size (big-endian)
+ *     Octets 8-15:       eCryptfs special marker
+ *     Octets 16-19:      Flags
+ *      Octet 16:         File format version number (between 0 and 255)
+ *      Octets 17-18:     Reserved
+ *      Octet 19:         Bit 1 (lsb): Reserved
+ *                        Bit 2: Encrypted?
+ *                        Bits 3-8: Reserved
+ *     Octets 20-23:      Header extent size (big-endian)
+ *     Octets 24-25:      Number of header extents at front of file
+ *                        (big-endian)
+ *     Octet  26:         Begin RFC 2440 authentication token packet set
+ *   Data Extent 0:
+ *     Lower data (CBC encrypted)
+ *   Data Extent 1:
+ *     Lower data (CBC encrypted)
+ *   ...
+ *
+ * Returns zero on success
+ */
+static int ecryptfs_write_headers_virt(char *page_virt, size_t max,
+				       size_t *size,
+				       struct ecryptfs_crypt_stat *crypt_stat,
+				       struct dentry *ecryptfs_dentry)
+{
+	int rc;
+	size_t written;
+	size_t offset;
+
+	offset = ECRYPTFS_FILE_SIZE_BYTES;
+	write_ecryptfs_marker((page_virt + offset), &written);
+	offset += written;
+	ecryptfs_write_crypt_stat_flags((page_virt + offset), crypt_stat,
+					&written);
+	offset += written;
+	ecryptfs_write_header_metadata((page_virt + offset), crypt_stat,
+				       &written);
+	offset += written;
+	rc = ecryptfs_generate_key_packet_set((page_virt + offset), crypt_stat,
+					      ecryptfs_dentry, &written,
+					      max - offset);
+	if (rc)
+		ecryptfs_printk(KERN_WARNING, "Error generating key packet "
+				"set; rc = [%d]\n", rc);
+	if (size) {
+		offset += written;
+		*size = offset;
+	}
+	return rc;
+}
+
+static int
+ecryptfs_write_metadata_to_contents(struct inode *ecryptfs_inode,
+				    char *virt, size_t virt_len)
+{
+	int rc;
+
+	rc = ecryptfs_write_lower(ecryptfs_inode, virt,
+				  0, virt_len);
+	if (rc < 0)
+		printk(KERN_ERR "%s: Error attempting to write header "
+		       "information to lower file; rc = [%d]\n", __func__, rc);
+	else
+		rc = 0;
+	return rc;
+}
+
+static int
+ecryptfs_write_metadata_to_xattr(struct dentry *ecryptfs_dentry,
+				 struct inode *ecryptfs_inode,
+				 char *page_virt, size_t size)
+{
+	int rc;
+	struct dentry *lower_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry);
+	struct inode *lower_inode = d_inode(lower_dentry);
+
+	if (!(lower_inode->i_opflags & IOP_XATTR)) {
+		rc = -EOPNOTSUPP;
+		goto out;
+	}
+
+	inode_lock(lower_inode);
+	rc = __vfs_setxattr(&nop_mnt_idmap, lower_dentry, lower_inode,
+			    ECRYPTFS_XATTR_NAME, page_virt, size, 0);
+	if (!rc && ecryptfs_inode)
+		fsstack_copy_attr_all(ecryptfs_inode, lower_inode);
+	inode_unlock(lower_inode);
+out:
+	return rc;
+}
+
+static unsigned long ecryptfs_get_zeroed_pages(gfp_t gfp_mask,
+					       unsigned int order)
+{
+	struct page *page;
+
+	page = alloc_pages(gfp_mask | __GFP_ZERO, order);
+	if (page)
+		return (unsigned long) page_address(page);
+	return 0;
+}
+
+/**
+ * ecryptfs_write_metadata
+ * @ecryptfs_dentry: The eCryptfs dentry, which should be negative
+ * @ecryptfs_inode: The newly created eCryptfs inode
+ *
+ * Write the file headers out.  This will likely involve a userspace
+ * callout, in which the session key is encrypted with one or more
+ * public keys and/or the passphrase necessary to do the encryption is
+ * retrieved via a prompt.  Exactly what happens at this point should
+ * be policy-dependent.
+ *
+ * Returns zero on success; non-zero on error
+ */
+int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry,
+			    struct inode *ecryptfs_inode)
+{
+	struct ecryptfs_crypt_stat *crypt_stat =
+		&ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
+	unsigned int order;
+	char *virt;
+	size_t virt_len;
+	size_t size = 0;
+	int rc = 0;
+
+	if (likely(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
+		if (!(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
+			printk(KERN_ERR "Key is invalid; bailing out\n");
+			rc = -EINVAL;
+			goto out;
+		}
+	} else {
+		printk(KERN_WARNING "%s: Encrypted flag not set\n",
+		       __func__);
+		rc = -EINVAL;
+		goto out;
+	}
+	virt_len = crypt_stat->metadata_size;
+	order = get_order(virt_len);
+	/* Released in this function */
+	virt = (char *)ecryptfs_get_zeroed_pages(GFP_KERNEL, order);
+	if (!virt) {
+		printk(KERN_ERR "%s: Out of memory\n", __func__);
+		rc = -ENOMEM;
+		goto out;
+	}
+	/* Zeroed page ensures the in-header unencrypted i_size is set to 0 */
+	rc = ecryptfs_write_headers_virt(virt, virt_len, &size, crypt_stat,
+					 ecryptfs_dentry);
+	if (unlikely(rc)) {
+		printk(KERN_ERR "%s: Error whilst writing headers; rc = [%d]\n",
+		       __func__, rc);
+		goto out_free;
+	}
+	if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
+		rc = ecryptfs_write_metadata_to_xattr(ecryptfs_dentry, ecryptfs_inode,
+						      virt, size);
+	else
+		rc = ecryptfs_write_metadata_to_contents(ecryptfs_inode, virt,
+							 virt_len);
+	if (rc) {
+		printk(KERN_ERR "%s: Error writing metadata out to lower file; "
+		       "rc = [%d]\n", __func__, rc);
+		goto out_free;
+	}
+out_free:
+	free_pages((unsigned long)virt, order);
+out:
+	return rc;
+}
+
+#define ECRYPTFS_DONT_VALIDATE_HEADER_SIZE 0
+#define ECRYPTFS_VALIDATE_HEADER_SIZE 1
+static int parse_header_metadata(struct ecryptfs_crypt_stat *crypt_stat,
+				 char *virt, int *bytes_read,
+				 int validate_header_size)
+{
+	int rc = 0;
+	u32 header_extent_size;
+	u16 num_header_extents_at_front;
+
+	header_extent_size = get_unaligned_be32(virt);
+	virt += sizeof(__be32);
+	num_header_extents_at_front = get_unaligned_be16(virt);
+	crypt_stat->metadata_size = (((size_t)num_header_extents_at_front
+				     * (size_t)header_extent_size));
+	(*bytes_read) = (sizeof(__be32) + sizeof(__be16));
+	if ((validate_header_size == ECRYPTFS_VALIDATE_HEADER_SIZE)
+	    && (crypt_stat->metadata_size
+		< ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE)) {
+		rc = -EINVAL;
+		printk(KERN_WARNING "Invalid header size: [%zd]\n",
+		       crypt_stat->metadata_size);
+	}
+	return rc;
+}
+
+/**
+ * set_default_header_data
+ * @crypt_stat: The cryptographic context
+ *
+ * For version 0 file format; this function is only for backwards
+ * compatibility for files created with the prior versions of
+ * eCryptfs.
+ */
+static void set_default_header_data(struct ecryptfs_crypt_stat *crypt_stat)
+{
+	crypt_stat->metadata_size = ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE;
+}
+
+void ecryptfs_i_size_init(const char *page_virt, struct inode *inode)
+{
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
+	struct ecryptfs_crypt_stat *crypt_stat;
+	u64 file_size;
+
+	crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
+	mount_crypt_stat =
+		&ecryptfs_superblock_to_private(inode->i_sb)->mount_crypt_stat;
+	if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED) {
+		file_size = i_size_read(ecryptfs_inode_to_lower(inode));
+		if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
+			file_size += crypt_stat->metadata_size;
+	} else
+		file_size = get_unaligned_be64(page_virt);
+	i_size_write(inode, (loff_t)file_size);
+	crypt_stat->flags |= ECRYPTFS_I_SIZE_INITIALIZED;
+}
+
+/**
+ * ecryptfs_read_headers_virt
+ * @page_virt: The virtual address into which to read the headers
+ * @crypt_stat: The cryptographic context
+ * @ecryptfs_dentry: The eCryptfs dentry
+ * @validate_header_size: Whether to validate the header size while reading
+ *
+ * Read/parse the header data. The header format is detailed in the
+ * comment block for the ecryptfs_write_headers_virt() function.
+ *
+ * Returns zero on success
+ */
+static int ecryptfs_read_headers_virt(char *page_virt,
+				      struct ecryptfs_crypt_stat *crypt_stat,
+				      struct dentry *ecryptfs_dentry,
+				      int validate_header_size)
+{
+	int rc = 0;
+	int offset;
+	int bytes_read;
+
+	ecryptfs_set_default_sizes(crypt_stat);
+	crypt_stat->mount_crypt_stat = &ecryptfs_superblock_to_private(
+		ecryptfs_dentry->d_sb)->mount_crypt_stat;
+	offset = ECRYPTFS_FILE_SIZE_BYTES;
+	rc = ecryptfs_validate_marker(page_virt + offset);
+	if (rc)
+		goto out;
+	if (!(crypt_stat->flags & ECRYPTFS_I_SIZE_INITIALIZED))
+		ecryptfs_i_size_init(page_virt, d_inode(ecryptfs_dentry));
+	offset += MAGIC_ECRYPTFS_MARKER_SIZE_BYTES;
+	ecryptfs_process_flags(crypt_stat, (page_virt + offset), &bytes_read);
+	if (crypt_stat->file_version > ECRYPTFS_SUPPORTED_FILE_VERSION) {
+		ecryptfs_printk(KERN_WARNING, "File version is [%d]; only "
+				"file version [%d] is supported by this "
+				"version of eCryptfs\n",
+				crypt_stat->file_version,
+				ECRYPTFS_SUPPORTED_FILE_VERSION);
+		rc = -EINVAL;
+		goto out;
+	}
+	offset += bytes_read;
+	if (crypt_stat->file_version >= 1) {
+		rc = parse_header_metadata(crypt_stat, (page_virt + offset),
+					   &bytes_read, validate_header_size);
+		if (rc) {
+			ecryptfs_printk(KERN_WARNING, "Error reading header "
+					"metadata; rc = [%d]\n", rc);
+		}
+		offset += bytes_read;
+	} else
+		set_default_header_data(crypt_stat);
+	rc = ecryptfs_parse_packet_set(crypt_stat, (page_virt + offset),
+				       ecryptfs_dentry);
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_read_xattr_region
+ * @page_virt: The vitual address into which to read the xattr data
+ * @ecryptfs_inode: The eCryptfs inode
+ *
+ * Attempts to read the crypto metadata from the extended attribute
+ * region of the lower file.
+ *
+ * Returns zero on success; non-zero on error
+ */
+int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode)
+{
+	struct dentry *lower_dentry =
+		ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_path.dentry;
+	ssize_t size;
+	int rc = 0;
+
+	size = ecryptfs_getxattr_lower(lower_dentry,
+				       ecryptfs_inode_to_lower(ecryptfs_inode),
+				       ECRYPTFS_XATTR_NAME,
+				       page_virt, ECRYPTFS_DEFAULT_EXTENT_SIZE);
+	if (size < 0) {
+		if (unlikely(ecryptfs_verbosity > 0))
+			printk(KERN_INFO "Error attempting to read the [%s] "
+			       "xattr from the lower file; return value = "
+			       "[%zd]\n", ECRYPTFS_XATTR_NAME, size);
+		rc = -EINVAL;
+		goto out;
+	}
+out:
+	return rc;
+}
+
+int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry,
+					    struct inode *inode)
+{
+	u8 file_size[ECRYPTFS_SIZE_AND_MARKER_BYTES];
+	u8 *marker = file_size + ECRYPTFS_FILE_SIZE_BYTES;
+	int rc;
+
+	rc = ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
+				     ecryptfs_inode_to_lower(inode),
+				     ECRYPTFS_XATTR_NAME, file_size,
+				     ECRYPTFS_SIZE_AND_MARKER_BYTES);
+	if (rc < 0)
+		return rc;
+	else if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
+		return -EINVAL;
+	rc = ecryptfs_validate_marker(marker);
+	if (!rc)
+		ecryptfs_i_size_init(file_size, inode);
+	return rc;
+}
+
+/*
+ * ecryptfs_read_metadata
+ *
+ * Common entry point for reading file metadata. From here, we could
+ * retrieve the header information from the header region of the file,
+ * the xattr region of the file, or some other repository that is
+ * stored separately from the file itself. The current implementation
+ * supports retrieving the metadata information from the file contents
+ * and from the xattr region.
+ *
+ * Returns zero if valid headers found and parsed; non-zero otherwise
+ */
+int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry)
+{
+	int rc;
+	char *page_virt;
+	struct inode *ecryptfs_inode = d_inode(ecryptfs_dentry);
+	struct ecryptfs_crypt_stat *crypt_stat =
+	    &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
+		&ecryptfs_superblock_to_private(
+			ecryptfs_dentry->d_sb)->mount_crypt_stat;
+
+	ecryptfs_copy_mount_wide_flags_to_inode_flags(crypt_stat,
+						      mount_crypt_stat);
+	/* Read the first page from the underlying file */
+	page_virt = kmem_cache_alloc(ecryptfs_header_cache, GFP_USER);
+	if (!page_virt) {
+		rc = -ENOMEM;
+		goto out;
+	}
+	rc = ecryptfs_read_lower(page_virt, 0, crypt_stat->extent_size,
+				 ecryptfs_inode);
+	if (rc >= 0)
+		rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
+						ecryptfs_dentry,
+						ECRYPTFS_VALIDATE_HEADER_SIZE);
+	if (rc) {
+		/* metadata is not in the file header, so try xattrs */
+		memset(page_virt, 0, PAGE_SIZE);
+		rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode);
+		if (rc) {
+			printk(KERN_DEBUG "Valid eCryptfs headers not found in "
+			       "file header region or xattr region, inode %lu\n",
+				ecryptfs_inode->i_ino);
+			rc = -EINVAL;
+			goto out;
+		}
+		rc = ecryptfs_read_headers_virt(page_virt, crypt_stat,
+						ecryptfs_dentry,
+						ECRYPTFS_DONT_VALIDATE_HEADER_SIZE);
+		if (rc) {
+			printk(KERN_DEBUG "Valid eCryptfs headers not found in "
+			       "file xattr region either, inode %lu\n",
+				ecryptfs_inode->i_ino);
+			rc = -EINVAL;
+		}
+		if (crypt_stat->mount_crypt_stat->flags
+		    & ECRYPTFS_XATTR_METADATA_ENABLED) {
+			crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
+		} else {
+			printk(KERN_WARNING "Attempt to access file with "
+			       "crypto metadata only in the extended attribute "
+			       "region, but eCryptfs was mounted without "
+			       "xattr support enabled. eCryptfs will not treat "
+			       "this like an encrypted file, inode %lu\n",
+				ecryptfs_inode->i_ino);
+			rc = -EINVAL;
+		}
+	}
+out:
+	if (page_virt) {
+		memset(page_virt, 0, PAGE_SIZE);
+		kmem_cache_free(ecryptfs_header_cache, page_virt);
+	}
+	return rc;
+}
+
+/*
+ * ecryptfs_encrypt_filename - encrypt filename
+ *
+ * CBC-encrypts the filename. We do not want to encrypt the same
+ * filename with the same key and IV, which may happen with hard
+ * links, so we prepend random bits to each filename.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int
+ecryptfs_encrypt_filename(struct ecryptfs_filename *filename,
+			  struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
+{
+	int rc = 0;
+
+	filename->encrypted_filename = NULL;
+	filename->encrypted_filename_size = 0;
+	if (mount_crypt_stat && (mount_crypt_stat->flags
+				     & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)) {
+		size_t packet_size;
+		size_t remaining_bytes;
+
+		rc = ecryptfs_write_tag_70_packet(
+			NULL, NULL,
+			&filename->encrypted_filename_size,
+			mount_crypt_stat, NULL,
+			filename->filename_size);
+		if (rc) {
+			printk(KERN_ERR "%s: Error attempting to get packet "
+			       "size for tag 72; rc = [%d]\n", __func__,
+			       rc);
+			filename->encrypted_filename_size = 0;
+			goto out;
+		}
+		filename->encrypted_filename =
+			kmalloc(filename->encrypted_filename_size, GFP_KERNEL);
+		if (!filename->encrypted_filename) {
+			rc = -ENOMEM;
+			goto out;
+		}
+		remaining_bytes = filename->encrypted_filename_size;
+		rc = ecryptfs_write_tag_70_packet(filename->encrypted_filename,
+						  &remaining_bytes,
+						  &packet_size,
+						  mount_crypt_stat,
+						  filename->filename,
+						  filename->filename_size);
+		if (rc) {
+			printk(KERN_ERR "%s: Error attempting to generate "
+			       "tag 70 packet; rc = [%d]\n", __func__,
+			       rc);
+			kfree(filename->encrypted_filename);
+			filename->encrypted_filename = NULL;
+			filename->encrypted_filename_size = 0;
+			goto out;
+		}
+		filename->encrypted_filename_size = packet_size;
+	} else {
+		printk(KERN_ERR "%s: No support for requested filename "
+		       "encryption method in this release\n", __func__);
+		rc = -EOPNOTSUPP;
+		goto out;
+	}
+out:
+	return rc;
+}
+
+static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
+				  const char *name, size_t name_size)
+{
+	int rc = 0;
+
+	(*copied_name) = kmalloc((name_size + 1), GFP_KERNEL);
+	if (!(*copied_name)) {
+		rc = -ENOMEM;
+		goto out;
+	}
+	memcpy((void *)(*copied_name), (void *)name, name_size);
+	(*copied_name)[(name_size)] = '\0';	/* Only for convenience
+						 * in printing out the
+						 * string in debug
+						 * messages */
+	(*copied_name_size) = name_size;
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_process_key_cipher - Perform key cipher initialization.
+ * @key_tfm: Crypto context for key material, set by this function
+ * @cipher_name: Name of the cipher
+ * @key_size: Size of the key in bytes
+ *
+ * Returns zero on success. Any crypto_tfm structs allocated here
+ * should be released by other functions, such as on a superblock put
+ * event, regardless of whether this function succeeds for fails.
+ */
+static int
+ecryptfs_process_key_cipher(struct crypto_skcipher **key_tfm,
+			    char *cipher_name, size_t *key_size)
+{
+	char dummy_key[ECRYPTFS_MAX_KEY_BYTES];
+	char *full_alg_name = NULL;
+	int rc;
+
+	*key_tfm = NULL;
+	if (*key_size > ECRYPTFS_MAX_KEY_BYTES) {
+		rc = -EINVAL;
+		printk(KERN_ERR "Requested key size is [%zd] bytes; maximum "
+		      "allowable is [%d]\n", *key_size, ECRYPTFS_MAX_KEY_BYTES);
+		goto out;
+	}
+	rc = ecryptfs_crypto_api_algify_cipher_name(&full_alg_name, cipher_name,
+						    "ecb");
+	if (rc)
+		goto out;
+	*key_tfm = crypto_alloc_skcipher(full_alg_name, 0, CRYPTO_ALG_ASYNC);
+	if (IS_ERR(*key_tfm)) {
+		rc = PTR_ERR(*key_tfm);
+		printk(KERN_ERR "Unable to allocate crypto cipher with name "
+		       "[%s]; rc = [%d]\n", full_alg_name, rc);
+		goto out;
+	}
+	crypto_skcipher_set_flags(*key_tfm, CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
+	if (*key_size == 0)
+		*key_size = crypto_skcipher_max_keysize(*key_tfm);
+	get_random_bytes(dummy_key, *key_size);
+	rc = crypto_skcipher_setkey(*key_tfm, dummy_key, *key_size);
+	if (rc) {
+		printk(KERN_ERR "Error attempting to set key of size [%zd] for "
+		       "cipher [%s]; rc = [%d]\n", *key_size, full_alg_name,
+		       rc);
+		rc = -EINVAL;
+		goto out;
+	}
+out:
+	kfree(full_alg_name);
+	return rc;
+}
+
+struct kmem_cache *ecryptfs_key_tfm_cache;
+static struct list_head key_tfm_list;
+DEFINE_MUTEX(key_tfm_list_mutex);
+
+int __init ecryptfs_init_crypto(void)
+{
+	INIT_LIST_HEAD(&key_tfm_list);
+	return 0;
+}
+
+/**
+ * ecryptfs_destroy_crypto - free all cached key_tfms on key_tfm_list
+ *
+ * Called only at module unload time
+ */
+int ecryptfs_destroy_crypto(void)
+{
+	struct ecryptfs_key_tfm *key_tfm, *key_tfm_tmp;
+
+	mutex_lock(&key_tfm_list_mutex);
+	list_for_each_entry_safe(key_tfm, key_tfm_tmp, &key_tfm_list,
+				 key_tfm_list) {
+		list_del(&key_tfm->key_tfm_list);
+		crypto_free_skcipher(key_tfm->key_tfm);
+		kmem_cache_free(ecryptfs_key_tfm_cache, key_tfm);
+	}
+	mutex_unlock(&key_tfm_list_mutex);
+	return 0;
+}
+
+int
+ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
+			 size_t key_size)
+{
+	struct ecryptfs_key_tfm *tmp_tfm;
+	int rc = 0;
+
+	BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
+
+	tmp_tfm = kmem_cache_alloc(ecryptfs_key_tfm_cache, GFP_KERNEL);
+	if (key_tfm)
+		(*key_tfm) = tmp_tfm;
+	if (!tmp_tfm) {
+		rc = -ENOMEM;
+		goto out;
+	}
+	mutex_init(&tmp_tfm->key_tfm_mutex);
+	strncpy(tmp_tfm->cipher_name, cipher_name,
+		ECRYPTFS_MAX_CIPHER_NAME_SIZE);
+	tmp_tfm->cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
+	tmp_tfm->key_size = key_size;
+	rc = ecryptfs_process_key_cipher(&tmp_tfm->key_tfm,
+					 tmp_tfm->cipher_name,
+					 &tmp_tfm->key_size);
+	if (rc) {
+		printk(KERN_ERR "Error attempting to initialize key TFM "
+		       "cipher with name = [%s]; rc = [%d]\n",
+		       tmp_tfm->cipher_name, rc);
+		kmem_cache_free(ecryptfs_key_tfm_cache, tmp_tfm);
+		if (key_tfm)
+			(*key_tfm) = NULL;
+		goto out;
+	}
+	list_add(&tmp_tfm->key_tfm_list, &key_tfm_list);
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_tfm_exists - Search for existing tfm for cipher_name.
+ * @cipher_name: the name of the cipher to search for
+ * @key_tfm: set to corresponding tfm if found
+ *
+ * Searches for cached key_tfm matching @cipher_name
+ * Must be called with &key_tfm_list_mutex held
+ * Returns 1 if found, with @key_tfm set
+ * Returns 0 if not found, with @key_tfm set to NULL
+ */
+int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm)
+{
+	struct ecryptfs_key_tfm *tmp_key_tfm;
+
+	BUG_ON(!mutex_is_locked(&key_tfm_list_mutex));
+
+	list_for_each_entry(tmp_key_tfm, &key_tfm_list, key_tfm_list) {
+		if (strcmp(tmp_key_tfm->cipher_name, cipher_name) == 0) {
+			if (key_tfm)
+				(*key_tfm) = tmp_key_tfm;
+			return 1;
+		}
+	}
+	if (key_tfm)
+		(*key_tfm) = NULL;
+	return 0;
+}
+
+/**
+ * ecryptfs_get_tfm_and_mutex_for_cipher_name
+ *
+ * @tfm: set to cached tfm found, or new tfm created
+ * @tfm_mutex: set to mutex for cached tfm found, or new tfm created
+ * @cipher_name: the name of the cipher to search for and/or add
+ *
+ * Sets pointers to @tfm & @tfm_mutex matching @cipher_name.
+ * Searches for cached item first, and creates new if not found.
+ * Returns 0 on success, non-zero if adding new cipher failed
+ */
+int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_skcipher **tfm,
+					       struct mutex **tfm_mutex,
+					       char *cipher_name)
+{
+	struct ecryptfs_key_tfm *key_tfm;
+	int rc = 0;
+
+	(*tfm) = NULL;
+	(*tfm_mutex) = NULL;
+
+	mutex_lock(&key_tfm_list_mutex);
+	if (!ecryptfs_tfm_exists(cipher_name, &key_tfm)) {
+		rc = ecryptfs_add_new_key_tfm(&key_tfm, cipher_name, 0);
+		if (rc) {
+			printk(KERN_ERR "Error adding new key_tfm to list; "
+					"rc = [%d]\n", rc);
+			goto out;
+		}
+	}
+	(*tfm) = key_tfm->key_tfm;
+	(*tfm_mutex) = &key_tfm->key_tfm_mutex;
+out:
+	mutex_unlock(&key_tfm_list_mutex);
+	return rc;
+}
+
+/* 64 characters forming a 6-bit target field */
+static unsigned char *portable_filename_chars = ("-.0123456789ABCD"
+						 "EFGHIJKLMNOPQRST"
+						 "UVWXYZabcdefghij"
+						 "klmnopqrstuvwxyz");
+
+/* We could either offset on every reverse map or just pad some 0x00's
+ * at the front here */
+static const unsigned char filename_rev_map[256] = {
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 7 */
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 15 */
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 23 */
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 31 */
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 39 */
+	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, /* 47 */
+	0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, /* 55 */
+	0x0A, 0x0B, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, /* 63 */
+	0x00, 0x0C, 0x0D, 0x0E, 0x0F, 0x10, 0x11, 0x12, /* 71 */
+	0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, /* 79 */
+	0x1B, 0x1C, 0x1D, 0x1E, 0x1F, 0x20, 0x21, 0x22, /* 87 */
+	0x23, 0x24, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, /* 95 */
+	0x00, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, /* 103 */
+	0x2D, 0x2E, 0x2F, 0x30, 0x31, 0x32, 0x33, 0x34, /* 111 */
+	0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, /* 119 */
+	0x3D, 0x3E, 0x3F /* 123 - 255 initialized to 0x00 */
+};
+
+/**
+ * ecryptfs_encode_for_filename
+ * @dst: Destination location for encoded filename
+ * @dst_size: Size of the encoded filename in bytes
+ * @src: Source location for the filename to encode
+ * @src_size: Size of the source in bytes
+ */
+static void ecryptfs_encode_for_filename(unsigned char *dst, size_t *dst_size,
+				  unsigned char *src, size_t src_size)
+{
+	size_t num_blocks;
+	size_t block_num = 0;
+	size_t dst_offset = 0;
+	unsigned char last_block[3];
+
+	if (src_size == 0) {
+		(*dst_size) = 0;
+		goto out;
+	}
+	num_blocks = (src_size / 3);
+	if ((src_size % 3) == 0) {
+		memcpy(last_block, (&src[src_size - 3]), 3);
+	} else {
+		num_blocks++;
+		last_block[2] = 0x00;
+		switch (src_size % 3) {
+		case 1:
+			last_block[0] = src[src_size - 1];
+			last_block[1] = 0x00;
+			break;
+		case 2:
+			last_block[0] = src[src_size - 2];
+			last_block[1] = src[src_size - 1];
+		}
+	}
+	(*dst_size) = (num_blocks * 4);
+	if (!dst)
+		goto out;
+	while (block_num < num_blocks) {
+		unsigned char *src_block;
+		unsigned char dst_block[4];
+
+		if (block_num == (num_blocks - 1))
+			src_block = last_block;
+		else
+			src_block = &src[block_num * 3];
+		dst_block[0] = ((src_block[0] >> 2) & 0x3F);
+		dst_block[1] = (((src_block[0] << 4) & 0x30)
+				| ((src_block[1] >> 4) & 0x0F));
+		dst_block[2] = (((src_block[1] << 2) & 0x3C)
+				| ((src_block[2] >> 6) & 0x03));
+		dst_block[3] = (src_block[2] & 0x3F);
+		dst[dst_offset++] = portable_filename_chars[dst_block[0]];
+		dst[dst_offset++] = portable_filename_chars[dst_block[1]];
+		dst[dst_offset++] = portable_filename_chars[dst_block[2]];
+		dst[dst_offset++] = portable_filename_chars[dst_block[3]];
+		block_num++;
+	}
+out:
+	return;
+}
+
+static size_t ecryptfs_max_decoded_size(size_t encoded_size)
+{
+	/* Not exact; conservatively long. Every block of 4
+	 * encoded characters decodes into a block of 3
+	 * decoded characters. This segment of code provides
+	 * the caller with the maximum amount of allocated
+	 * space that @dst will need to point to in a
+	 * subsequent call. */
+	return ((encoded_size + 1) * 3) / 4;
+}
+
+/**
+ * ecryptfs_decode_from_filename
+ * @dst: If NULL, this function only sets @dst_size and returns. If
+ *       non-NULL, this function decodes the encoded octets in @src
+ *       into the memory that @dst points to.
+ * @dst_size: Set to the size of the decoded string.
+ * @src: The encoded set of octets to decode.
+ * @src_size: The size of the encoded set of octets to decode.
+ */
+static void
+ecryptfs_decode_from_filename(unsigned char *dst, size_t *dst_size,
+			      const unsigned char *src, size_t src_size)
+{
+	u8 current_bit_offset = 0;
+	size_t src_byte_offset = 0;
+	size_t dst_byte_offset = 0;
+
+	if (!dst) {
+		(*dst_size) = ecryptfs_max_decoded_size(src_size);
+		goto out;
+	}
+	while (src_byte_offset < src_size) {
+		unsigned char src_byte =
+				filename_rev_map[(int)src[src_byte_offset]];
+
+		switch (current_bit_offset) {
+		case 0:
+			dst[dst_byte_offset] = (src_byte << 2);
+			current_bit_offset = 6;
+			break;
+		case 6:
+			dst[dst_byte_offset++] |= (src_byte >> 4);
+			dst[dst_byte_offset] = ((src_byte & 0xF)
+						 << 4);
+			current_bit_offset = 4;
+			break;
+		case 4:
+			dst[dst_byte_offset++] |= (src_byte >> 2);
+			dst[dst_byte_offset] = (src_byte << 6);
+			current_bit_offset = 2;
+			break;
+		case 2:
+			dst[dst_byte_offset++] |= (src_byte);
+			current_bit_offset = 0;
+			break;
+		}
+		src_byte_offset++;
+	}
+	(*dst_size) = dst_byte_offset;
+out:
+	return;
+}
+
+/**
+ * ecryptfs_encrypt_and_encode_filename - converts a plaintext file name to cipher text
+ * @encoded_name: The encrypted name
+ * @encoded_name_size: Length of the encrypted name
+ * @mount_crypt_stat: The crypt_stat struct associated with the file name to encode
+ * @name: The plaintext name
+ * @name_size: The length of the plaintext name
+ *
+ * Encrypts and encodes a filename into something that constitutes a
+ * valid filename for a filesystem, with printable characters.
+ *
+ * We assume that we have a properly initialized crypto context,
+ * pointed to by crypt_stat->tfm.
+ *
+ * Returns zero on success; non-zero on otherwise
+ */
+int ecryptfs_encrypt_and_encode_filename(
+	char **encoded_name,
+	size_t *encoded_name_size,
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
+	const char *name, size_t name_size)
+{
+	size_t encoded_name_no_prefix_size;
+	int rc = 0;
+
+	(*encoded_name) = NULL;
+	(*encoded_name_size) = 0;
+	if (mount_crypt_stat && (mount_crypt_stat->flags
+				     & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) {
+		struct ecryptfs_filename *filename;
+
+		filename = kzalloc(sizeof(*filename), GFP_KERNEL);
+		if (!filename) {
+			rc = -ENOMEM;
+			goto out;
+		}
+		filename->filename = (char *)name;
+		filename->filename_size = name_size;
+		rc = ecryptfs_encrypt_filename(filename, mount_crypt_stat);
+		if (rc) {
+			printk(KERN_ERR "%s: Error attempting to encrypt "
+			       "filename; rc = [%d]\n", __func__, rc);
+			kfree(filename);
+			goto out;
+		}
+		ecryptfs_encode_for_filename(
+			NULL, &encoded_name_no_prefix_size,
+			filename->encrypted_filename,
+			filename->encrypted_filename_size);
+		if (mount_crypt_stat
+			&& (mount_crypt_stat->flags
+			    & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK))
+			(*encoded_name_size) =
+				(ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
+				 + encoded_name_no_prefix_size);
+		else
+			(*encoded_name_size) =
+				(ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE
+				 + encoded_name_no_prefix_size);
+		(*encoded_name) = kmalloc((*encoded_name_size) + 1, GFP_KERNEL);
+		if (!(*encoded_name)) {
+			rc = -ENOMEM;
+			kfree(filename->encrypted_filename);
+			kfree(filename);
+			goto out;
+		}
+		if (mount_crypt_stat
+			&& (mount_crypt_stat->flags
+			    & ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK)) {
+			memcpy((*encoded_name),
+			       ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
+			       ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE);
+			ecryptfs_encode_for_filename(
+			    ((*encoded_name)
+			     + ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE),
+			    &encoded_name_no_prefix_size,
+			    filename->encrypted_filename,
+			    filename->encrypted_filename_size);
+			(*encoded_name_size) =
+				(ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE
+				 + encoded_name_no_prefix_size);
+			(*encoded_name)[(*encoded_name_size)] = '\0';
+		} else {
+			rc = -EOPNOTSUPP;
+		}
+		if (rc) {
+			printk(KERN_ERR "%s: Error attempting to encode "
+			       "encrypted filename; rc = [%d]\n", __func__,
+			       rc);
+			kfree((*encoded_name));
+			(*encoded_name) = NULL;
+			(*encoded_name_size) = 0;
+		}
+		kfree(filename->encrypted_filename);
+		kfree(filename);
+	} else {
+		rc = ecryptfs_copy_filename(encoded_name,
+					    encoded_name_size,
+					    name, name_size);
+	}
+out:
+	return rc;
+}
+
+static bool is_dot_dotdot(const char *name, size_t name_size)
+{
+	if (name_size == 1 && name[0] == '.')
+		return true;
+	else if (name_size == 2 && name[0] == '.' && name[1] == '.')
+		return true;
+
+	return false;
+}
+
+/**
+ * ecryptfs_decode_and_decrypt_filename - converts the encoded cipher text name to decoded plaintext
+ * @plaintext_name: The plaintext name
+ * @plaintext_name_size: The plaintext name size
+ * @sb: Ecryptfs's super_block
+ * @name: The filename in cipher text
+ * @name_size: The cipher text name size
+ *
+ * Decrypts and decodes the filename.
+ *
+ * Returns zero on error; non-zero otherwise
+ */
+int ecryptfs_decode_and_decrypt_filename(char **plaintext_name,
+					 size_t *plaintext_name_size,
+					 struct super_block *sb,
+					 const char *name, size_t name_size)
+{
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
+		&ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
+	char *decoded_name;
+	size_t decoded_name_size;
+	size_t packet_size;
+	int rc = 0;
+
+	if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) &&
+	    !(mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)) {
+		if (is_dot_dotdot(name, name_size)) {
+			rc = ecryptfs_copy_filename(plaintext_name,
+						    plaintext_name_size,
+						    name, name_size);
+			goto out;
+		}
+
+		if (name_size <= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE ||
+		    strncmp(name, ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX,
+			    ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE)) {
+			rc = -EINVAL;
+			goto out;
+		}
+
+		name += ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
+		name_size -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
+		ecryptfs_decode_from_filename(NULL, &decoded_name_size,
+					      name, name_size);
+		decoded_name = kmalloc(decoded_name_size, GFP_KERNEL);
+		if (!decoded_name) {
+			rc = -ENOMEM;
+			goto out;
+		}
+		ecryptfs_decode_from_filename(decoded_name, &decoded_name_size,
+					      name, name_size);
+		rc = ecryptfs_parse_tag_70_packet(plaintext_name,
+						  plaintext_name_size,
+						  &packet_size,
+						  mount_crypt_stat,
+						  decoded_name,
+						  decoded_name_size);
+		if (rc) {
+			ecryptfs_printk(KERN_DEBUG,
+					"%s: Could not parse tag 70 packet from filename\n",
+					__func__);
+			goto out_free;
+		}
+	} else {
+		rc = ecryptfs_copy_filename(plaintext_name,
+					    plaintext_name_size,
+					    name, name_size);
+		goto out;
+	}
+out_free:
+	kfree(decoded_name);
+out:
+	return rc;
+}
+
+#define ENC_NAME_MAX_BLOCKLEN_8_OR_16	143
+
+int ecryptfs_set_f_namelen(long *namelen, long lower_namelen,
+			   struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
+{
+	struct crypto_skcipher *tfm;
+	struct mutex *tfm_mutex;
+	size_t cipher_blocksize;
+	int rc;
+
+	if (!(mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)) {
+		(*namelen) = lower_namelen;
+		return 0;
+	}
+
+	rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
+			mount_crypt_stat->global_default_fn_cipher_name);
+	if (unlikely(rc)) {
+		(*namelen) = 0;
+		return rc;
+	}
+
+	mutex_lock(tfm_mutex);
+	cipher_blocksize = crypto_skcipher_blocksize(tfm);
+	mutex_unlock(tfm_mutex);
+
+	/* Return an exact amount for the common cases */
+	if (lower_namelen == NAME_MAX
+	    && (cipher_blocksize == 8 || cipher_blocksize == 16)) {
+		(*namelen) = ENC_NAME_MAX_BLOCKLEN_8_OR_16;
+		return 0;
+	}
+
+	/* Return a safe estimate for the uncommon cases */
+	(*namelen) = lower_namelen;
+	(*namelen) -= ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE;
+	/* Since this is the max decoded size, subtract 1 "decoded block" len */
+	(*namelen) = ecryptfs_max_decoded_size(*namelen) - 3;
+	(*namelen) -= ECRYPTFS_TAG_70_MAX_METADATA_SIZE;
+	(*namelen) -= ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES;
+	/* Worst case is that the filename is padded nearly a full block size */
+	(*namelen) -= cipher_blocksize - 1;
+
+	if ((*namelen) < 0)
+		(*namelen) = 0;
+
+	return 0;
+}
diff --git a/fs/ecryptfs/debug.c b/fs/ecryptfs/debug.c
new file mode 100644
index 000000000..cf6d0e8e2
--- /dev/null
+++ b/fs/ecryptfs/debug.c
@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * eCryptfs: Linux filesystem encryption layer
+ * Functions only useful for debugging.
+ *
+ * Copyright (C) 2006 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
+ */
+
+#include "ecryptfs_kernel.h"
+
+/*
+ * ecryptfs_dump_auth_tok - debug function to print auth toks
+ *
+ * This function will print the contents of an ecryptfs authentication
+ * token.
+ */
+void ecryptfs_dump_auth_tok(struct ecryptfs_auth_tok *auth_tok)
+{
+	char salt[ECRYPTFS_SALT_SIZE * 2 + 1];
+	char sig[ECRYPTFS_SIG_SIZE_HEX + 1];
+
+	ecryptfs_printk(KERN_DEBUG, "Auth tok at mem loc [%p]:\n",
+			auth_tok);
+	if (auth_tok->flags & ECRYPTFS_PRIVATE_KEY) {
+		ecryptfs_printk(KERN_DEBUG, " * private key type\n");
+	} else {
+		ecryptfs_printk(KERN_DEBUG, " * passphrase type\n");
+		ecryptfs_to_hex(salt, auth_tok->token.password.salt,
+				ECRYPTFS_SALT_SIZE);
+		salt[ECRYPTFS_SALT_SIZE * 2] = '\0';
+		ecryptfs_printk(KERN_DEBUG, " * salt = [%s]\n", salt);
+		if (auth_tok->token.password.flags &
+		    ECRYPTFS_PERSISTENT_PASSWORD) {
+			ecryptfs_printk(KERN_DEBUG, " * persistent\n");
+		}
+		memcpy(sig, auth_tok->token.password.signature,
+		       ECRYPTFS_SIG_SIZE_HEX);
+		sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
+		ecryptfs_printk(KERN_DEBUG, " * signature = [%s]\n", sig);
+	}
+	ecryptfs_printk(KERN_DEBUG, " * session_key.flags = [0x%x]\n",
+			auth_tok->session_key.flags);
+	if (auth_tok->session_key.flags
+	    & ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT)
+		ecryptfs_printk(KERN_DEBUG,
+				" * Userspace decrypt request set\n");
+	if (auth_tok->session_key.flags
+	    & ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT)
+		ecryptfs_printk(KERN_DEBUG,
+				" * Userspace encrypt request set\n");
+	if (auth_tok->session_key.flags & ECRYPTFS_CONTAINS_DECRYPTED_KEY) {
+		ecryptfs_printk(KERN_DEBUG, " * Contains decrypted key\n");
+		ecryptfs_printk(KERN_DEBUG,
+				" * session_key.decrypted_key_size = [0x%x]\n",
+				auth_tok->session_key.decrypted_key_size);
+		ecryptfs_printk(KERN_DEBUG, " * Decrypted session key "
+				"dump:\n");
+		if (ecryptfs_verbosity > 0)
+			ecryptfs_dump_hex(auth_tok->session_key.decrypted_key,
+					  ECRYPTFS_DEFAULT_KEY_BYTES);
+	}
+	if (auth_tok->session_key.flags & ECRYPTFS_CONTAINS_ENCRYPTED_KEY) {
+		ecryptfs_printk(KERN_DEBUG, " * Contains encrypted key\n");
+		ecryptfs_printk(KERN_DEBUG,
+				" * session_key.encrypted_key_size = [0x%x]\n",
+				auth_tok->session_key.encrypted_key_size);
+		ecryptfs_printk(KERN_DEBUG, " * Encrypted session key "
+				"dump:\n");
+		if (ecryptfs_verbosity > 0)
+			ecryptfs_dump_hex(auth_tok->session_key.encrypted_key,
+					  auth_tok->session_key.
+					  encrypted_key_size);
+	}
+}
+
+/**
+ * ecryptfs_dump_hex - debug hex printer
+ * @data: string of bytes to be printed
+ * @bytes: number of bytes to print
+ *
+ * Dump hexadecimal representation of char array
+ */
+void ecryptfs_dump_hex(char *data, int bytes)
+{
+	if (ecryptfs_verbosity < 1)
+		return;
+
+	print_hex_dump(KERN_DEBUG, "ecryptfs: ", DUMP_PREFIX_OFFSET, 16, 1,
+		       data, bytes, false);
+}
diff --git a/fs/ecryptfs/dentry.c b/fs/ecryptfs/dentry.c
new file mode 100644
index 000000000..acaa0825e
--- /dev/null
+++ b/fs/ecryptfs/dentry.c
@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 1997-2003 Erez Zadok
+ * Copyright (C) 2001-2003 Stony Brook University
+ * Copyright (C) 2004-2006 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
+ */
+
+#include <linux/dcache.h>
+#include <linux/namei.h>
+#include <linux/mount.h>
+#include <linux/fs_stack.h>
+#include <linux/slab.h>
+#include "ecryptfs_kernel.h"
+
+/**
+ * ecryptfs_d_revalidate - revalidate an ecryptfs dentry
+ * @dentry: The ecryptfs dentry
+ * @flags: lookup flags
+ *
+ * Called when the VFS needs to revalidate a dentry. This
+ * is called whenever a name lookup finds a dentry in the
+ * dcache. Most filesystems leave this as NULL, because all their
+ * dentries in the dcache are valid.
+ *
+ * Returns 1 if valid, 0 otherwise.
+ *
+ */
+static int ecryptfs_d_revalidate(struct dentry *dentry, unsigned int flags)
+{
+	struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
+	int rc = 1;
+
+	if (flags & LOOKUP_RCU)
+		return -ECHILD;
+
+	if (lower_dentry->d_flags & DCACHE_OP_REVALIDATE)
+		rc = lower_dentry->d_op->d_revalidate(lower_dentry, flags);
+
+	if (d_really_is_positive(dentry)) {
+		struct inode *inode = d_inode(dentry);
+
+		fsstack_copy_attr_all(inode, ecryptfs_inode_to_lower(inode));
+		if (!inode->i_nlink)
+			return 0;
+	}
+	return rc;
+}
+
+struct kmem_cache *ecryptfs_dentry_info_cache;
+
+static void ecryptfs_dentry_free_rcu(struct rcu_head *head)
+{
+	kmem_cache_free(ecryptfs_dentry_info_cache,
+		container_of(head, struct ecryptfs_dentry_info, rcu));
+}
+
+/**
+ * ecryptfs_d_release
+ * @dentry: The ecryptfs dentry
+ *
+ * Called when a dentry is really deallocated.
+ */
+static void ecryptfs_d_release(struct dentry *dentry)
+{
+	struct ecryptfs_dentry_info *p = dentry->d_fsdata;
+	if (p) {
+		path_put(&p->lower_path);
+		call_rcu(&p->rcu, ecryptfs_dentry_free_rcu);
+	}
+}
+
+const struct dentry_operations ecryptfs_dops = {
+	.d_revalidate = ecryptfs_d_revalidate,
+	.d_release = ecryptfs_d_release,
+};
diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h
new file mode 100644
index 000000000..f2ed0c026
--- /dev/null
+++ b/fs/ecryptfs/ecryptfs_kernel.h
@@ -0,0 +1,707 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/**
+ * eCryptfs: Linux filesystem encryption layer
+ * Kernel declarations.
+ *
+ * Copyright (C) 1997-2003 Erez Zadok
+ * Copyright (C) 2001-2003 Stony Brook University
+ * Copyright (C) 2004-2008 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
+ *              Trevor S. Highland <trevor.highland@gmail.com>
+ *              Tyler Hicks <code@tyhicks.com>
+ */
+
+#ifndef ECRYPTFS_KERNEL_H
+#define ECRYPTFS_KERNEL_H
+
+#include <crypto/skcipher.h>
+#include <keys/user-type.h>
+#include <keys/encrypted-type.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/fs_stack.h>
+#include <linux/namei.h>
+#include <linux/scatterlist.h>
+#include <linux/hash.h>
+#include <linux/nsproxy.h>
+#include <linux/backing-dev.h>
+#include <linux/ecryptfs.h>
+
+#define ECRYPTFS_DEFAULT_IV_BYTES 16
+#define ECRYPTFS_DEFAULT_EXTENT_SIZE 4096
+#define ECRYPTFS_MINIMUM_HEADER_EXTENT_SIZE 8192
+#define ECRYPTFS_DEFAULT_MSG_CTX_ELEMS 32
+#define ECRYPTFS_DEFAULT_SEND_TIMEOUT HZ
+#define ECRYPTFS_MAX_MSG_CTX_TTL (HZ*3)
+#define ECRYPTFS_DEFAULT_NUM_USERS 4
+#define ECRYPTFS_MAX_NUM_USERS 32768
+#define ECRYPTFS_XATTR_NAME "user.ecryptfs"
+
+void ecryptfs_dump_auth_tok(struct ecryptfs_auth_tok *auth_tok);
+static inline void
+ecryptfs_to_hex(char *dst, char *src, size_t src_size)
+{
+	char *end = bin2hex(dst, src, src_size);
+	*end = '\0';
+}
+
+extern void ecryptfs_from_hex(char *dst, char *src, int dst_size);
+
+struct ecryptfs_key_record {
+	unsigned char type;
+	size_t enc_key_size;
+	unsigned char sig[ECRYPTFS_SIG_SIZE];
+	unsigned char enc_key[ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES];
+};
+
+struct ecryptfs_auth_tok_list {
+	struct ecryptfs_auth_tok *auth_tok;
+	struct list_head list;
+};
+
+struct ecryptfs_crypt_stat;
+struct ecryptfs_mount_crypt_stat;
+
+struct ecryptfs_page_crypt_context {
+	struct page *page;
+#define ECRYPTFS_PREPARE_COMMIT_MODE 0
+#define ECRYPTFS_WRITEPAGE_MODE      1
+	unsigned int mode;
+	union {
+		struct file *lower_file;
+		struct writeback_control *wbc;
+	} param;
+};
+
+#if defined(CONFIG_ENCRYPTED_KEYS) || defined(CONFIG_ENCRYPTED_KEYS_MODULE)
+static inline struct ecryptfs_auth_tok *
+ecryptfs_get_encrypted_key_payload_data(struct key *key)
+{
+	struct encrypted_key_payload *payload;
+
+	if (key->type != &key_type_encrypted)
+		return NULL;
+
+	payload = key->payload.data[0];
+	if (!payload)
+		return ERR_PTR(-EKEYREVOKED);
+
+	return (struct ecryptfs_auth_tok *)payload->payload_data;
+}
+
+static inline struct key *ecryptfs_get_encrypted_key(char *sig)
+{
+	return request_key(&key_type_encrypted, sig, NULL);
+}
+
+#else
+static inline struct ecryptfs_auth_tok *
+ecryptfs_get_encrypted_key_payload_data(struct key *key)
+{
+	return NULL;
+}
+
+static inline struct key *ecryptfs_get_encrypted_key(char *sig)
+{
+	return ERR_PTR(-ENOKEY);
+}
+
+#endif /* CONFIG_ENCRYPTED_KEYS */
+
+static inline struct ecryptfs_auth_tok *
+ecryptfs_get_key_payload_data(struct key *key)
+{
+	struct ecryptfs_auth_tok *auth_tok;
+	struct user_key_payload *ukp;
+
+	auth_tok = ecryptfs_get_encrypted_key_payload_data(key);
+	if (auth_tok)
+		return auth_tok;
+
+	ukp = user_key_payload_locked(key);
+	if (!ukp)
+		return ERR_PTR(-EKEYREVOKED);
+
+	return (struct ecryptfs_auth_tok *)ukp->data;
+}
+
+#define ECRYPTFS_MAX_KEYSET_SIZE 1024
+#define ECRYPTFS_MAX_CIPHER_NAME_SIZE 31
+#define ECRYPTFS_MAX_NUM_ENC_KEYS 64
+#define ECRYPTFS_MAX_IV_BYTES 16	/* 128 bits */
+#define ECRYPTFS_SALT_BYTES 2
+#define MAGIC_ECRYPTFS_MARKER 0x3c81b7f5
+#define MAGIC_ECRYPTFS_MARKER_SIZE_BYTES 8	/* 4*2 */
+#define ECRYPTFS_FILE_SIZE_BYTES (sizeof(u64))
+#define ECRYPTFS_SIZE_AND_MARKER_BYTES (ECRYPTFS_FILE_SIZE_BYTES \
+					+ MAGIC_ECRYPTFS_MARKER_SIZE_BYTES)
+#define ECRYPTFS_DEFAULT_CIPHER "aes"
+#define ECRYPTFS_DEFAULT_KEY_BYTES 16
+#define ECRYPTFS_DEFAULT_HASH "md5"
+#define ECRYPTFS_TAG_70_DIGEST ECRYPTFS_DEFAULT_HASH
+#define ECRYPTFS_TAG_1_PACKET_TYPE 0x01
+#define ECRYPTFS_TAG_3_PACKET_TYPE 0x8C
+#define ECRYPTFS_TAG_11_PACKET_TYPE 0xED
+#define ECRYPTFS_TAG_64_PACKET_TYPE 0x40
+#define ECRYPTFS_TAG_65_PACKET_TYPE 0x41
+#define ECRYPTFS_TAG_66_PACKET_TYPE 0x42
+#define ECRYPTFS_TAG_67_PACKET_TYPE 0x43
+#define ECRYPTFS_TAG_70_PACKET_TYPE 0x46 /* FNEK-encrypted filename
+					  * as dentry name */
+#define ECRYPTFS_TAG_71_PACKET_TYPE 0x47 /* FNEK-encrypted filename in
+					  * metadata */
+#define ECRYPTFS_TAG_72_PACKET_TYPE 0x48 /* FEK-encrypted filename as
+					  * dentry name */
+#define ECRYPTFS_TAG_73_PACKET_TYPE 0x49 /* FEK-encrypted filename as
+					  * metadata */
+#define ECRYPTFS_MIN_PKT_LEN_SIZE 1 /* Min size to specify packet length */
+#define ECRYPTFS_MAX_PKT_LEN_SIZE 2 /* Pass at least this many bytes to
+				     * ecryptfs_parse_packet_length() and
+				     * ecryptfs_write_packet_length()
+				     */
+/* Constraint: ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES >=
+ * ECRYPTFS_MAX_IV_BYTES */
+#define ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES 16
+#define ECRYPTFS_NON_NULL 0x42 /* A reasonable substitute for NULL */
+#define MD5_DIGEST_SIZE 16
+#define ECRYPTFS_TAG_70_DIGEST_SIZE MD5_DIGEST_SIZE
+#define ECRYPTFS_TAG_70_MIN_METADATA_SIZE (1 + ECRYPTFS_MIN_PKT_LEN_SIZE \
+					   + ECRYPTFS_SIG_SIZE + 1 + 1)
+#define ECRYPTFS_TAG_70_MAX_METADATA_SIZE (1 + ECRYPTFS_MAX_PKT_LEN_SIZE \
+					   + ECRYPTFS_SIG_SIZE + 1 + 1)
+#define ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX "ECRYPTFS_FEK_ENCRYPTED."
+#define ECRYPTFS_FEK_ENCRYPTED_FILENAME_PREFIX_SIZE 23
+#define ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX "ECRYPTFS_FNEK_ENCRYPTED."
+#define ECRYPTFS_FNEK_ENCRYPTED_FILENAME_PREFIX_SIZE 24
+#define ECRYPTFS_ENCRYPTED_DENTRY_NAME_LEN (18 + 1 + 4 + 1 + 32)
+
+#ifdef CONFIG_ECRYPT_FS_MESSAGING
+# define ECRYPTFS_VERSIONING_MASK_MESSAGING (ECRYPTFS_VERSIONING_DEVMISC \
+					     | ECRYPTFS_VERSIONING_PUBKEY)
+#else
+# define ECRYPTFS_VERSIONING_MASK_MESSAGING 0
+#endif
+
+#define ECRYPTFS_VERSIONING_MASK (ECRYPTFS_VERSIONING_PASSPHRASE \
+				  | ECRYPTFS_VERSIONING_PLAINTEXT_PASSTHROUGH \
+				  | ECRYPTFS_VERSIONING_XATTR \
+				  | ECRYPTFS_VERSIONING_MULTKEY \
+				  | ECRYPTFS_VERSIONING_MASK_MESSAGING \
+				  | ECRYPTFS_VERSIONING_FILENAME_ENCRYPTION)
+struct ecryptfs_key_sig {
+	struct list_head crypt_stat_list;
+	char keysig[ECRYPTFS_SIG_SIZE_HEX + 1];
+};
+
+struct ecryptfs_filename {
+	struct list_head crypt_stat_list;
+#define ECRYPTFS_FILENAME_CONTAINS_DECRYPTED 0x00000001
+	u32 flags;
+	u32 seq_no;
+	char *filename;
+	char *encrypted_filename;
+	size_t filename_size;
+	size_t encrypted_filename_size;
+	char fnek_sig[ECRYPTFS_SIG_SIZE_HEX];
+	char dentry_name[ECRYPTFS_ENCRYPTED_DENTRY_NAME_LEN + 1];
+};
+
+/**
+ * This is the primary struct associated with each encrypted file.
+ *
+ * TODO: cache align/pack?
+ */
+struct ecryptfs_crypt_stat {
+#define ECRYPTFS_STRUCT_INITIALIZED   0x00000001
+#define ECRYPTFS_POLICY_APPLIED       0x00000002
+#define ECRYPTFS_ENCRYPTED            0x00000004
+#define ECRYPTFS_SECURITY_WARNING     0x00000008
+#define ECRYPTFS_ENABLE_HMAC          0x00000010
+#define ECRYPTFS_ENCRYPT_IV_PAGES     0x00000020
+#define ECRYPTFS_KEY_VALID            0x00000040
+#define ECRYPTFS_METADATA_IN_XATTR    0x00000080
+#define ECRYPTFS_VIEW_AS_ENCRYPTED    0x00000100
+#define ECRYPTFS_KEY_SET              0x00000200
+#define ECRYPTFS_ENCRYPT_FILENAMES    0x00000400
+#define ECRYPTFS_ENCFN_USE_MOUNT_FNEK 0x00000800
+#define ECRYPTFS_ENCFN_USE_FEK        0x00001000
+#define ECRYPTFS_UNLINK_SIGS          0x00002000
+#define ECRYPTFS_I_SIZE_INITIALIZED   0x00004000
+	u32 flags;
+	unsigned int file_version;
+	size_t iv_bytes;
+	size_t metadata_size;
+	size_t extent_size; /* Data extent size; default is 4096 */
+	size_t key_size;
+	size_t extent_shift;
+	unsigned int extent_mask;
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
+	struct crypto_skcipher *tfm;
+	struct crypto_shash *hash_tfm; /* Crypto context for generating
+					* the initialization vectors */
+	unsigned char cipher[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1];
+	unsigned char key[ECRYPTFS_MAX_KEY_BYTES];
+	unsigned char root_iv[ECRYPTFS_MAX_IV_BYTES];
+	struct list_head keysig_list;
+	struct mutex keysig_list_mutex;
+	struct mutex cs_tfm_mutex;
+	struct mutex cs_mutex;
+};
+
+/* inode private data. */
+struct ecryptfs_inode_info {
+	struct inode vfs_inode;
+	struct inode *wii_inode;
+	struct mutex lower_file_mutex;
+	atomic_t lower_file_count;
+	struct file *lower_file;
+	struct ecryptfs_crypt_stat crypt_stat;
+};
+
+/* dentry private data. Each dentry must keep track of a lower
+ * vfsmount too. */
+struct ecryptfs_dentry_info {
+	struct path lower_path;
+	struct rcu_head rcu;
+};
+
+/**
+ * ecryptfs_global_auth_tok - A key used to encrypt all new files under the mountpoint
+ * @flags: Status flags
+ * @mount_crypt_stat_list: These auth_toks hang off the mount-wide
+ *                         cryptographic context. Every time a new
+ *                         inode comes into existence, eCryptfs copies
+ *                         the auth_toks on that list to the set of
+ *                         auth_toks on the inode's crypt_stat
+ * @global_auth_tok_key: The key from the user's keyring for the sig
+ * @global_auth_tok: The key contents
+ * @sig: The key identifier
+ *
+ * ecryptfs_global_auth_tok structs refer to authentication token keys
+ * in the user keyring that apply to newly created files. A list of
+ * these objects hangs off of the mount_crypt_stat struct for any
+ * given eCryptfs mount. This struct maintains a reference to both the
+ * key contents and the key itself so that the key can be put on
+ * unmount.
+ */
+struct ecryptfs_global_auth_tok {
+#define ECRYPTFS_AUTH_TOK_INVALID 0x00000001
+#define ECRYPTFS_AUTH_TOK_FNEK    0x00000002
+	u32 flags;
+	struct list_head mount_crypt_stat_list;
+	struct key *global_auth_tok_key;
+	unsigned char sig[ECRYPTFS_SIG_SIZE_HEX + 1];
+};
+
+/**
+ * ecryptfs_key_tfm - Persistent key tfm
+ * @key_tfm: crypto API handle to the key
+ * @key_size: Key size in bytes
+ * @key_tfm_mutex: Mutex to ensure only one operation in eCryptfs is
+ *                 using the persistent TFM at any point in time
+ * @key_tfm_list: Handle to hang this off the module-wide TFM list
+ * @cipher_name: String name for the cipher for this TFM
+ *
+ * Typically, eCryptfs will use the same ciphers repeatedly throughout
+ * the course of its operations. In order to avoid unnecessarily
+ * destroying and initializing the same cipher repeatedly, eCryptfs
+ * keeps a list of crypto API contexts around to use when needed.
+ */
+struct ecryptfs_key_tfm {
+	struct crypto_skcipher *key_tfm;
+	size_t key_size;
+	struct mutex key_tfm_mutex;
+	struct list_head key_tfm_list;
+	unsigned char cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1];
+};
+
+extern struct mutex key_tfm_list_mutex;
+
+/**
+ * This struct is to enable a mount-wide passphrase/salt combo. This
+ * is more or less a stopgap to provide similar functionality to other
+ * crypto filesystems like EncFS or CFS until full policy support is
+ * implemented in eCryptfs.
+ */
+struct ecryptfs_mount_crypt_stat {
+	/* Pointers to memory we do not own, do not free these */
+#define ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED 0x00000001
+#define ECRYPTFS_XATTR_METADATA_ENABLED        0x00000002
+#define ECRYPTFS_ENCRYPTED_VIEW_ENABLED        0x00000004
+#define ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED  0x00000008
+#define ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES      0x00000010
+#define ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK   0x00000020
+#define ECRYPTFS_GLOBAL_ENCFN_USE_FEK          0x00000040
+#define ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY    0x00000080
+	u32 flags;
+	struct list_head global_auth_tok_list;
+	struct mutex global_auth_tok_list_mutex;
+	size_t global_default_cipher_key_size;
+	size_t global_default_fn_cipher_key_bytes;
+	unsigned char global_default_cipher_name[ECRYPTFS_MAX_CIPHER_NAME_SIZE
+						 + 1];
+	unsigned char global_default_fn_cipher_name[
+		ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1];
+	char global_default_fnek_sig[ECRYPTFS_SIG_SIZE_HEX + 1];
+};
+
+/* superblock private data. */
+struct ecryptfs_sb_info {
+	struct super_block *wsi_sb;
+	struct ecryptfs_mount_crypt_stat mount_crypt_stat;
+};
+
+/* file private data. */
+struct ecryptfs_file_info {
+	struct file *wfi_file;
+	struct ecryptfs_crypt_stat *crypt_stat;
+};
+
+/* auth_tok <=> encrypted_session_key mappings */
+struct ecryptfs_auth_tok_list_item {
+	unsigned char encrypted_session_key[ECRYPTFS_MAX_KEY_BYTES];
+	struct list_head list;
+	struct ecryptfs_auth_tok auth_tok;
+};
+
+struct ecryptfs_message {
+	/* Can never be greater than ecryptfs_message_buf_len */
+	/* Used to find the parent msg_ctx */
+	/* Inherits from msg_ctx->index */
+	u32 index;
+	u32 data_len;
+	u8 data[];
+};
+
+struct ecryptfs_msg_ctx {
+#define ECRYPTFS_MSG_CTX_STATE_FREE     0x01
+#define ECRYPTFS_MSG_CTX_STATE_PENDING  0x02
+#define ECRYPTFS_MSG_CTX_STATE_DONE     0x03
+#define ECRYPTFS_MSG_CTX_STATE_NO_REPLY 0x04
+	u8 state;
+#define ECRYPTFS_MSG_HELO 100
+#define ECRYPTFS_MSG_QUIT 101
+#define ECRYPTFS_MSG_REQUEST 102
+#define ECRYPTFS_MSG_RESPONSE 103
+	u8 type;
+	u32 index;
+	/* Counter converts to a sequence number. Each message sent
+	 * out for which we expect a response has an associated
+	 * sequence number. The response must have the same sequence
+	 * number as the counter for the msg_stc for the message to be
+	 * valid. */
+	u32 counter;
+	size_t msg_size;
+	struct ecryptfs_message *msg;
+	struct task_struct *task;
+	struct list_head node;
+	struct list_head daemon_out_list;
+	struct mutex mux;
+};
+
+struct ecryptfs_daemon {
+#define ECRYPTFS_DAEMON_IN_READ      0x00000001
+#define ECRYPTFS_DAEMON_IN_POLL      0x00000002
+#define ECRYPTFS_DAEMON_ZOMBIE       0x00000004
+#define ECRYPTFS_DAEMON_MISCDEV_OPEN 0x00000008
+	u32 flags;
+	u32 num_queued_msg_ctx;
+	struct file *file;
+	struct mutex mux;
+	struct list_head msg_ctx_out_queue;
+	wait_queue_head_t wait;
+	struct hlist_node euid_chain;
+};
+
+#ifdef CONFIG_ECRYPT_FS_MESSAGING
+extern struct mutex ecryptfs_daemon_hash_mux;
+#endif
+
+static inline size_t
+ecryptfs_lower_header_size(struct ecryptfs_crypt_stat *crypt_stat)
+{
+	if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
+		return 0;
+	return crypt_stat->metadata_size;
+}
+
+static inline struct ecryptfs_file_info *
+ecryptfs_file_to_private(struct file *file)
+{
+	return file->private_data;
+}
+
+static inline void
+ecryptfs_set_file_private(struct file *file,
+			  struct ecryptfs_file_info *file_info)
+{
+	file->private_data = file_info;
+}
+
+static inline struct file *ecryptfs_file_to_lower(struct file *file)
+{
+	return ((struct ecryptfs_file_info *)file->private_data)->wfi_file;
+}
+
+static inline void
+ecryptfs_set_file_lower(struct file *file, struct file *lower_file)
+{
+	((struct ecryptfs_file_info *)file->private_data)->wfi_file =
+		lower_file;
+}
+
+static inline struct ecryptfs_inode_info *
+ecryptfs_inode_to_private(struct inode *inode)
+{
+	return container_of(inode, struct ecryptfs_inode_info, vfs_inode);
+}
+
+static inline struct inode *ecryptfs_inode_to_lower(struct inode *inode)
+{
+	return ecryptfs_inode_to_private(inode)->wii_inode;
+}
+
+static inline void
+ecryptfs_set_inode_lower(struct inode *inode, struct inode *lower_inode)
+{
+	ecryptfs_inode_to_private(inode)->wii_inode = lower_inode;
+}
+
+static inline struct ecryptfs_sb_info *
+ecryptfs_superblock_to_private(struct super_block *sb)
+{
+	return (struct ecryptfs_sb_info *)sb->s_fs_info;
+}
+
+static inline void
+ecryptfs_set_superblock_private(struct super_block *sb,
+				struct ecryptfs_sb_info *sb_info)
+{
+	sb->s_fs_info = sb_info;
+}
+
+static inline struct super_block *
+ecryptfs_superblock_to_lower(struct super_block *sb)
+{
+	return ((struct ecryptfs_sb_info *)sb->s_fs_info)->wsi_sb;
+}
+
+static inline void
+ecryptfs_set_superblock_lower(struct super_block *sb,
+			      struct super_block *lower_sb)
+{
+	((struct ecryptfs_sb_info *)sb->s_fs_info)->wsi_sb = lower_sb;
+}
+
+static inline void
+ecryptfs_set_dentry_private(struct dentry *dentry,
+			    struct ecryptfs_dentry_info *dentry_info)
+{
+	dentry->d_fsdata = dentry_info;
+}
+
+static inline struct dentry *
+ecryptfs_dentry_to_lower(struct dentry *dentry)
+{
+	return ((struct ecryptfs_dentry_info *)dentry->d_fsdata)->lower_path.dentry;
+}
+
+static inline const struct path *
+ecryptfs_dentry_to_lower_path(struct dentry *dentry)
+{
+	return &((struct ecryptfs_dentry_info *)dentry->d_fsdata)->lower_path;
+}
+
+#define ecryptfs_printk(type, fmt, arg...) \
+        __ecryptfs_printk(type "%s: " fmt, __func__, ## arg)
+__printf(1, 2)
+void __ecryptfs_printk(const char *fmt, ...);
+
+extern const struct file_operations ecryptfs_main_fops;
+extern const struct file_operations ecryptfs_dir_fops;
+extern const struct inode_operations ecryptfs_main_iops;
+extern const struct inode_operations ecryptfs_dir_iops;
+extern const struct inode_operations ecryptfs_symlink_iops;
+extern const struct super_operations ecryptfs_sops;
+extern const struct dentry_operations ecryptfs_dops;
+extern const struct address_space_operations ecryptfs_aops;
+extern int ecryptfs_verbosity;
+extern unsigned int ecryptfs_message_buf_len;
+extern signed long ecryptfs_message_wait_timeout;
+extern unsigned int ecryptfs_number_of_users;
+
+extern struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
+extern struct kmem_cache *ecryptfs_file_info_cache;
+extern struct kmem_cache *ecryptfs_dentry_info_cache;
+extern struct kmem_cache *ecryptfs_inode_info_cache;
+extern struct kmem_cache *ecryptfs_sb_info_cache;
+extern struct kmem_cache *ecryptfs_header_cache;
+extern struct kmem_cache *ecryptfs_xattr_cache;
+extern struct kmem_cache *ecryptfs_key_record_cache;
+extern struct kmem_cache *ecryptfs_key_sig_cache;
+extern struct kmem_cache *ecryptfs_global_auth_tok_cache;
+extern struct kmem_cache *ecryptfs_key_tfm_cache;
+
+struct inode *ecryptfs_get_inode(struct inode *lower_inode,
+				 struct super_block *sb);
+void ecryptfs_i_size_init(const char *page_virt, struct inode *inode);
+int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
+			     struct inode *ecryptfs_inode);
+int ecryptfs_decode_and_decrypt_filename(char **decrypted_name,
+					 size_t *decrypted_name_size,
+					 struct super_block *sb,
+					 const char *name, size_t name_size);
+int ecryptfs_fill_zeros(struct file *file, loff_t new_length);
+int ecryptfs_encrypt_and_encode_filename(
+	char **encoded_name,
+	size_t *encoded_name_size,
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
+	const char *name, size_t name_size);
+struct dentry *ecryptfs_lower_dentry(struct dentry *this_dentry);
+void ecryptfs_dump_hex(char *data, int bytes);
+int virt_to_scatterlist(const void *addr, int size, struct scatterlist *sg,
+			int sg_size);
+int ecryptfs_compute_root_iv(struct ecryptfs_crypt_stat *crypt_stat);
+void ecryptfs_rotate_iv(unsigned char *iv);
+int ecryptfs_init_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat);
+void ecryptfs_destroy_crypt_stat(struct ecryptfs_crypt_stat *crypt_stat);
+void ecryptfs_destroy_mount_crypt_stat(
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat);
+int ecryptfs_init_crypt_ctx(struct ecryptfs_crypt_stat *crypt_stat);
+int ecryptfs_write_inode_size_to_metadata(struct inode *ecryptfs_inode);
+int ecryptfs_encrypt_page(struct page *page);
+int ecryptfs_decrypt_page(struct page *page);
+int ecryptfs_write_metadata(struct dentry *ecryptfs_dentry,
+			    struct inode *ecryptfs_inode);
+int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry);
+int ecryptfs_new_file_context(struct inode *ecryptfs_inode);
+void ecryptfs_write_crypt_stat_flags(char *page_virt,
+				     struct ecryptfs_crypt_stat *crypt_stat,
+				     size_t *written);
+int ecryptfs_read_and_validate_header_region(struct inode *inode);
+int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry,
+					    struct inode *inode);
+u8 ecryptfs_code_for_cipher_string(char *cipher_name, size_t key_bytes);
+int ecryptfs_cipher_code_to_string(char *str, u8 cipher_code);
+void ecryptfs_set_default_sizes(struct ecryptfs_crypt_stat *crypt_stat);
+int ecryptfs_generate_key_packet_set(char *dest_base,
+				     struct ecryptfs_crypt_stat *crypt_stat,
+				     struct dentry *ecryptfs_dentry,
+				     size_t *len, size_t max);
+int
+ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
+			  unsigned char *src, struct dentry *ecryptfs_dentry);
+int ecryptfs_truncate(struct dentry *dentry, loff_t new_length);
+ssize_t
+ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode,
+			const char *name, void *value, size_t size);
+int
+ecryptfs_setxattr(struct dentry *dentry, struct inode *inode, const char *name,
+		  const void *value, size_t size, int flags);
+int ecryptfs_read_xattr_region(char *page_virt, struct inode *ecryptfs_inode);
+#ifdef CONFIG_ECRYPT_FS_MESSAGING
+int ecryptfs_process_response(struct ecryptfs_daemon *daemon,
+			      struct ecryptfs_message *msg, u32 seq);
+int ecryptfs_send_message(char *data, int data_len,
+			  struct ecryptfs_msg_ctx **msg_ctx);
+int ecryptfs_wait_for_response(struct ecryptfs_msg_ctx *msg_ctx,
+			       struct ecryptfs_message **emsg);
+int ecryptfs_init_messaging(void);
+void ecryptfs_release_messaging(void);
+#else
+static inline int ecryptfs_init_messaging(void)
+{
+	return 0;
+}
+static inline void ecryptfs_release_messaging(void)
+{ }
+static inline int ecryptfs_send_message(char *data, int data_len,
+					struct ecryptfs_msg_ctx **msg_ctx)
+{
+	return -ENOTCONN;
+}
+static inline int ecryptfs_wait_for_response(struct ecryptfs_msg_ctx *msg_ctx,
+					     struct ecryptfs_message **emsg)
+{
+	return -ENOMSG;
+}
+#endif
+
+void
+ecryptfs_write_header_metadata(char *virt,
+			       struct ecryptfs_crypt_stat *crypt_stat,
+			       size_t *written);
+int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig);
+int
+ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
+			   char *sig, u32 global_auth_tok_flags);
+int ecryptfs_get_global_auth_tok_for_sig(
+	struct ecryptfs_global_auth_tok **global_auth_tok,
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig);
+int
+ecryptfs_add_new_key_tfm(struct ecryptfs_key_tfm **key_tfm, char *cipher_name,
+			 size_t key_size);
+int ecryptfs_init_crypto(void);
+int ecryptfs_destroy_crypto(void);
+int ecryptfs_tfm_exists(char *cipher_name, struct ecryptfs_key_tfm **key_tfm);
+int ecryptfs_get_tfm_and_mutex_for_cipher_name(struct crypto_skcipher **tfm,
+					       struct mutex **tfm_mutex,
+					       char *cipher_name);
+int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
+				      struct ecryptfs_auth_tok **auth_tok,
+				      char *sig);
+int ecryptfs_write_lower(struct inode *ecryptfs_inode, char *data,
+			 loff_t offset, size_t size);
+int ecryptfs_write_lower_page_segment(struct inode *ecryptfs_inode,
+				      struct page *page_for_lower,
+				      size_t offset_in_page, size_t size);
+int ecryptfs_write(struct inode *inode, char *data, loff_t offset, size_t size);
+int ecryptfs_read_lower(char *data, loff_t offset, size_t size,
+			struct inode *ecryptfs_inode);
+int ecryptfs_read_lower_page_segment(struct page *page_for_ecryptfs,
+				     pgoff_t page_index,
+				     size_t offset_in_page, size_t size,
+				     struct inode *ecryptfs_inode);
+struct page *ecryptfs_get_locked_page(struct inode *inode, loff_t index);
+int ecryptfs_parse_packet_length(unsigned char *data, size_t *size,
+				 size_t *length_size);
+int ecryptfs_write_packet_length(char *dest, size_t size,
+				 size_t *packet_size_length);
+#ifdef CONFIG_ECRYPT_FS_MESSAGING
+int ecryptfs_init_ecryptfs_miscdev(void);
+void ecryptfs_destroy_ecryptfs_miscdev(void);
+int ecryptfs_send_miscdev(char *data, size_t data_size,
+			  struct ecryptfs_msg_ctx *msg_ctx, u8 msg_type,
+			  u16 msg_flags, struct ecryptfs_daemon *daemon);
+void ecryptfs_msg_ctx_alloc_to_free(struct ecryptfs_msg_ctx *msg_ctx);
+int
+ecryptfs_spawn_daemon(struct ecryptfs_daemon **daemon, struct file *file);
+int ecryptfs_exorcise_daemon(struct ecryptfs_daemon *daemon);
+int ecryptfs_find_daemon_by_euid(struct ecryptfs_daemon **daemon);
+#endif
+int ecryptfs_init_kthread(void);
+void ecryptfs_destroy_kthread(void);
+int ecryptfs_privileged_open(struct file **lower_file,
+			     struct dentry *lower_dentry,
+			     struct vfsmount *lower_mnt,
+			     const struct cred *cred);
+int ecryptfs_get_lower_file(struct dentry *dentry, struct inode *inode);
+void ecryptfs_put_lower_file(struct inode *inode);
+int
+ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
+			     size_t *packet_size,
+			     struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
+			     char *filename, size_t filename_size);
+int
+ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
+			     size_t *packet_size,
+			     struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
+			     char *data, size_t max_packet_size);
+int ecryptfs_set_f_namelen(long *namelen, long lower_namelen,
+			   struct ecryptfs_mount_crypt_stat *mount_crypt_stat);
+int ecryptfs_derive_iv(char *iv, struct ecryptfs_crypt_stat *crypt_stat,
+		       loff_t offset);
+
+extern const struct xattr_handler *ecryptfs_xattr_handlers[];
+
+#endif /* #ifndef ECRYPTFS_KERNEL_H */
diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
new file mode 100644
index 000000000..ce0a3c5ed
--- /dev/null
+++ b/fs/ecryptfs/file.c
@@ -0,0 +1,443 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 1997-2004 Erez Zadok
+ * Copyright (C) 2001-2004 Stony Brook University
+ * Copyright (C) 2004-2007 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
+ *   		Michael C. Thompson <mcthomps@us.ibm.com>
+ */
+
+#include <linux/file.h>
+#include <linux/poll.h>
+#include <linux/slab.h>
+#include <linux/mount.h>
+#include <linux/pagemap.h>
+#include <linux/security.h>
+#include <linux/compat.h>
+#include <linux/fs_stack.h>
+#include "ecryptfs_kernel.h"
+
+/*
+ * ecryptfs_read_update_atime
+ *
+ * generic_file_read updates the atime of upper layer inode.  But, it
+ * doesn't give us a chance to update the atime of the lower layer
+ * inode.  This function is a wrapper to generic_file_read.  It
+ * updates the atime of the lower level inode if generic_file_read
+ * returns without any errors. This is to be used only for file reads.
+ * The function to be used for directory reads is ecryptfs_read.
+ */
+static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb,
+				struct iov_iter *to)
+{
+	ssize_t rc;
+	const struct path *path;
+	struct file *file = iocb->ki_filp;
+
+	rc = generic_file_read_iter(iocb, to);
+	if (rc >= 0) {
+		path = ecryptfs_dentry_to_lower_path(file->f_path.dentry);
+		touch_atime(path);
+	}
+	return rc;
+}
+
+/*
+ * ecryptfs_splice_read_update_atime
+ *
+ * filemap_splice_read updates the atime of upper layer inode.  But, it
+ * doesn't give us a chance to update the atime of the lower layer inode.  This
+ * function is a wrapper to generic_file_read.  It updates the atime of the
+ * lower level inode if generic_file_read returns without any errors. This is
+ * to be used only for file reads.  The function to be used for directory reads
+ * is ecryptfs_read.
+ */
+static ssize_t ecryptfs_splice_read_update_atime(struct file *in, loff_t *ppos,
+						 struct pipe_inode_info *pipe,
+						 size_t len, unsigned int flags)
+{
+	ssize_t rc;
+	const struct path *path;
+
+	rc = filemap_splice_read(in, ppos, pipe, len, flags);
+	if (rc >= 0) {
+		path = ecryptfs_dentry_to_lower_path(in->f_path.dentry);
+		touch_atime(path);
+	}
+	return rc;
+}
+
+struct ecryptfs_getdents_callback {
+	struct dir_context ctx;
+	struct dir_context *caller;
+	struct super_block *sb;
+	int filldir_called;
+	int entries_written;
+};
+
+/* Inspired by generic filldir in fs/readdir.c */
+static bool
+ecryptfs_filldir(struct dir_context *ctx, const char *lower_name,
+		 int lower_namelen, loff_t offset, u64 ino, unsigned int d_type)
+{
+	struct ecryptfs_getdents_callback *buf =
+		container_of(ctx, struct ecryptfs_getdents_callback, ctx);
+	size_t name_size;
+	char *name;
+	int err;
+	bool res;
+
+	buf->filldir_called++;
+	err = ecryptfs_decode_and_decrypt_filename(&name, &name_size,
+						   buf->sb, lower_name,
+						   lower_namelen);
+	if (err) {
+		if (err != -EINVAL) {
+			ecryptfs_printk(KERN_DEBUG,
+					"%s: Error attempting to decode and decrypt filename [%s]; rc = [%d]\n",
+					__func__, lower_name, err);
+			return false;
+		}
+
+		/* Mask -EINVAL errors as these are most likely due a plaintext
+		 * filename present in the lower filesystem despite filename
+		 * encryption being enabled. One unavoidable example would be
+		 * the "lost+found" dentry in the root directory of an Ext4
+		 * filesystem.
+		 */
+		return true;
+	}
+
+	buf->caller->pos = buf->ctx.pos;
+	res = dir_emit(buf->caller, name, name_size, ino, d_type);
+	kfree(name);
+	if (res)
+		buf->entries_written++;
+	return res;
+}
+
+/**
+ * ecryptfs_readdir
+ * @file: The eCryptfs directory file
+ * @ctx: The actor to feed the entries to
+ */
+static int ecryptfs_readdir(struct file *file, struct dir_context *ctx)
+{
+	int rc;
+	struct file *lower_file;
+	struct inode *inode = file_inode(file);
+	struct ecryptfs_getdents_callback buf = {
+		.ctx.actor = ecryptfs_filldir,
+		.caller = ctx,
+		.sb = inode->i_sb,
+	};
+	lower_file = ecryptfs_file_to_lower(file);
+	rc = iterate_dir(lower_file, &buf.ctx);
+	ctx->pos = buf.ctx.pos;
+	if (rc >= 0 && (buf.entries_written || !buf.filldir_called))
+		fsstack_copy_attr_atime(inode, file_inode(lower_file));
+	return rc;
+}
+
+struct kmem_cache *ecryptfs_file_info_cache;
+
+static int read_or_initialize_metadata(struct dentry *dentry)
+{
+	struct inode *inode = d_inode(dentry);
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
+	struct ecryptfs_crypt_stat *crypt_stat;
+	int rc;
+
+	crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
+	mount_crypt_stat = &ecryptfs_superblock_to_private(
+						inode->i_sb)->mount_crypt_stat;
+	mutex_lock(&crypt_stat->cs_mutex);
+
+	if (crypt_stat->flags & ECRYPTFS_POLICY_APPLIED &&
+	    crypt_stat->flags & ECRYPTFS_KEY_VALID) {
+		rc = 0;
+		goto out;
+	}
+
+	rc = ecryptfs_read_metadata(dentry);
+	if (!rc)
+		goto out;
+
+	if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED) {
+		crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
+				       | ECRYPTFS_ENCRYPTED);
+		rc = 0;
+		goto out;
+	}
+
+	if (!(mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED) &&
+	    !i_size_read(ecryptfs_inode_to_lower(inode))) {
+		rc = ecryptfs_initialize_file(dentry, inode);
+		if (!rc)
+			goto out;
+	}
+
+	rc = -EIO;
+out:
+	mutex_unlock(&crypt_stat->cs_mutex);
+	return rc;
+}
+
+static int ecryptfs_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	struct file *lower_file = ecryptfs_file_to_lower(file);
+	/*
+	 * Don't allow mmap on top of file systems that don't support it
+	 * natively.  If FILESYSTEM_MAX_STACK_DEPTH > 2 or ecryptfs
+	 * allows recursive mounting, this will need to be extended.
+	 */
+	if (!lower_file->f_op->mmap)
+		return -ENODEV;
+	return generic_file_mmap(file, vma);
+}
+
+/**
+ * ecryptfs_open
+ * @inode: inode specifying file to open
+ * @file: Structure to return filled in
+ *
+ * Opens the file specified by inode.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int ecryptfs_open(struct inode *inode, struct file *file)
+{
+	int rc = 0;
+	struct ecryptfs_crypt_stat *crypt_stat = NULL;
+	struct dentry *ecryptfs_dentry = file->f_path.dentry;
+	/* Private value of ecryptfs_dentry allocated in
+	 * ecryptfs_lookup() */
+	struct ecryptfs_file_info *file_info;
+
+	/* Released in ecryptfs_release or end of function if failure */
+	file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
+	ecryptfs_set_file_private(file, file_info);
+	if (!file_info) {
+		ecryptfs_printk(KERN_ERR,
+				"Error attempting to allocate memory\n");
+		rc = -ENOMEM;
+		goto out;
+	}
+	crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
+	mutex_lock(&crypt_stat->cs_mutex);
+	if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)) {
+		ecryptfs_printk(KERN_DEBUG, "Setting flags for stat...\n");
+		/* Policy code enabled in future release */
+		crypt_stat->flags |= (ECRYPTFS_POLICY_APPLIED
+				      | ECRYPTFS_ENCRYPTED);
+	}
+	mutex_unlock(&crypt_stat->cs_mutex);
+	rc = ecryptfs_get_lower_file(ecryptfs_dentry, inode);
+	if (rc) {
+		printk(KERN_ERR "%s: Error attempting to initialize "
+			"the lower file for the dentry with name "
+			"[%pd]; rc = [%d]\n", __func__,
+			ecryptfs_dentry, rc);
+		goto out_free;
+	}
+	if ((ecryptfs_inode_to_private(inode)->lower_file->f_flags & O_ACCMODE)
+	    == O_RDONLY && (file->f_flags & O_ACCMODE) != O_RDONLY) {
+		rc = -EPERM;
+		printk(KERN_WARNING "%s: Lower file is RO; eCryptfs "
+		       "file must hence be opened RO\n", __func__);
+		goto out_put;
+	}
+	ecryptfs_set_file_lower(
+		file, ecryptfs_inode_to_private(inode)->lower_file);
+	rc = read_or_initialize_metadata(ecryptfs_dentry);
+	if (rc)
+		goto out_put;
+	ecryptfs_printk(KERN_DEBUG, "inode w/ addr = [0x%p], i_ino = "
+			"[0x%.16lx] size: [0x%.16llx]\n", inode, inode->i_ino,
+			(unsigned long long)i_size_read(inode));
+	goto out;
+out_put:
+	ecryptfs_put_lower_file(inode);
+out_free:
+	kmem_cache_free(ecryptfs_file_info_cache,
+			ecryptfs_file_to_private(file));
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_dir_open
+ * @inode: inode specifying file to open
+ * @file: Structure to return filled in
+ *
+ * Opens the file specified by inode.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int ecryptfs_dir_open(struct inode *inode, struct file *file)
+{
+	struct dentry *ecryptfs_dentry = file->f_path.dentry;
+	/* Private value of ecryptfs_dentry allocated in
+	 * ecryptfs_lookup() */
+	struct ecryptfs_file_info *file_info;
+	struct file *lower_file;
+
+	/* Released in ecryptfs_release or end of function if failure */
+	file_info = kmem_cache_zalloc(ecryptfs_file_info_cache, GFP_KERNEL);
+	ecryptfs_set_file_private(file, file_info);
+	if (unlikely(!file_info)) {
+		ecryptfs_printk(KERN_ERR,
+				"Error attempting to allocate memory\n");
+		return -ENOMEM;
+	}
+	lower_file = dentry_open(ecryptfs_dentry_to_lower_path(ecryptfs_dentry),
+				 file->f_flags, current_cred());
+	if (IS_ERR(lower_file)) {
+		printk(KERN_ERR "%s: Error attempting to initialize "
+			"the lower file for the dentry with name "
+			"[%pd]; rc = [%ld]\n", __func__,
+			ecryptfs_dentry, PTR_ERR(lower_file));
+		kmem_cache_free(ecryptfs_file_info_cache, file_info);
+		return PTR_ERR(lower_file);
+	}
+	ecryptfs_set_file_lower(file, lower_file);
+	return 0;
+}
+
+static int ecryptfs_flush(struct file *file, fl_owner_t td)
+{
+	struct file *lower_file = ecryptfs_file_to_lower(file);
+
+	if (lower_file->f_op->flush) {
+		filemap_write_and_wait(file->f_mapping);
+		return lower_file->f_op->flush(lower_file, td);
+	}
+
+	return 0;
+}
+
+static int ecryptfs_release(struct inode *inode, struct file *file)
+{
+	ecryptfs_put_lower_file(inode);
+	kmem_cache_free(ecryptfs_file_info_cache,
+			ecryptfs_file_to_private(file));
+	return 0;
+}
+
+static int ecryptfs_dir_release(struct inode *inode, struct file *file)
+{
+	fput(ecryptfs_file_to_lower(file));
+	kmem_cache_free(ecryptfs_file_info_cache,
+			ecryptfs_file_to_private(file));
+	return 0;
+}
+
+static loff_t ecryptfs_dir_llseek(struct file *file, loff_t offset, int whence)
+{
+	return vfs_llseek(ecryptfs_file_to_lower(file), offset, whence);
+}
+
+static int
+ecryptfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
+{
+	int rc;
+
+	rc = file_write_and_wait(file);
+	if (rc)
+		return rc;
+
+	return vfs_fsync(ecryptfs_file_to_lower(file), datasync);
+}
+
+static int ecryptfs_fasync(int fd, struct file *file, int flag)
+{
+	int rc = 0;
+	struct file *lower_file = NULL;
+
+	lower_file = ecryptfs_file_to_lower(file);
+	if (lower_file->f_op->fasync)
+		rc = lower_file->f_op->fasync(fd, lower_file, flag);
+	return rc;
+}
+
+static long
+ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct file *lower_file = ecryptfs_file_to_lower(file);
+	long rc = -ENOTTY;
+
+	if (!lower_file->f_op->unlocked_ioctl)
+		return rc;
+
+	switch (cmd) {
+	case FITRIM:
+	case FS_IOC_GETFLAGS:
+	case FS_IOC_SETFLAGS:
+	case FS_IOC_GETVERSION:
+	case FS_IOC_SETVERSION:
+		rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg);
+		fsstack_copy_attr_all(file_inode(file), file_inode(lower_file));
+
+		return rc;
+	default:
+		return rc;
+	}
+}
+
+#ifdef CONFIG_COMPAT
+static long
+ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+	struct file *lower_file = ecryptfs_file_to_lower(file);
+	long rc = -ENOIOCTLCMD;
+
+	if (!lower_file->f_op->compat_ioctl)
+		return rc;
+
+	switch (cmd) {
+	case FITRIM:
+	case FS_IOC32_GETFLAGS:
+	case FS_IOC32_SETFLAGS:
+	case FS_IOC32_GETVERSION:
+	case FS_IOC32_SETVERSION:
+		rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg);
+		fsstack_copy_attr_all(file_inode(file), file_inode(lower_file));
+
+		return rc;
+	default:
+		return rc;
+	}
+}
+#endif
+
+const struct file_operations ecryptfs_dir_fops = {
+	.iterate_shared = ecryptfs_readdir,
+	.read = generic_read_dir,
+	.unlocked_ioctl = ecryptfs_unlocked_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = ecryptfs_compat_ioctl,
+#endif
+	.open = ecryptfs_dir_open,
+	.release = ecryptfs_dir_release,
+	.fsync = ecryptfs_fsync,
+	.llseek = ecryptfs_dir_llseek,
+};
+
+const struct file_operations ecryptfs_main_fops = {
+	.llseek = generic_file_llseek,
+	.read_iter = ecryptfs_read_update_atime,
+	.write_iter = generic_file_write_iter,
+	.unlocked_ioctl = ecryptfs_unlocked_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = ecryptfs_compat_ioctl,
+#endif
+	.mmap = ecryptfs_mmap,
+	.open = ecryptfs_open,
+	.flush = ecryptfs_flush,
+	.release = ecryptfs_release,
+	.fsync = ecryptfs_fsync,
+	.fasync = ecryptfs_fasync,
+	.splice_read = ecryptfs_splice_read_update_atime,
+};
diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
new file mode 100644
index 000000000..5ab4b8788
--- /dev/null
+++ b/fs/ecryptfs/inode.c
@@ -0,0 +1,1224 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 1997-2004 Erez Zadok
+ * Copyright (C) 2001-2004 Stony Brook University
+ * Copyright (C) 2004-2007 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
+ *              Michael C. Thompsion <mcthomps@us.ibm.com>
+ */
+
+#include <linux/file.h>
+#include <linux/vmalloc.h>
+#include <linux/pagemap.h>
+#include <linux/dcache.h>
+#include <linux/namei.h>
+#include <linux/mount.h>
+#include <linux/fs_stack.h>
+#include <linux/slab.h>
+#include <linux/xattr.h>
+#include <linux/posix_acl.h>
+#include <linux/posix_acl_xattr.h>
+#include <linux/fileattr.h>
+#include <asm/unaligned.h>
+#include "ecryptfs_kernel.h"
+
+static int lock_parent(struct dentry *dentry,
+		       struct dentry **lower_dentry,
+		       struct inode **lower_dir)
+{
+	struct dentry *lower_dir_dentry;
+
+	lower_dir_dentry = ecryptfs_dentry_to_lower(dentry->d_parent);
+	*lower_dir = d_inode(lower_dir_dentry);
+	*lower_dentry = ecryptfs_dentry_to_lower(dentry);
+
+	inode_lock_nested(*lower_dir, I_MUTEX_PARENT);
+	return (*lower_dentry)->d_parent == lower_dir_dentry ? 0 : -EINVAL;
+}
+
+static int ecryptfs_inode_test(struct inode *inode, void *lower_inode)
+{
+	return ecryptfs_inode_to_lower(inode) == lower_inode;
+}
+
+static int ecryptfs_inode_set(struct inode *inode, void *opaque)
+{
+	struct inode *lower_inode = opaque;
+
+	ecryptfs_set_inode_lower(inode, lower_inode);
+	fsstack_copy_attr_all(inode, lower_inode);
+	/* i_size will be overwritten for encrypted regular files */
+	fsstack_copy_inode_size(inode, lower_inode);
+	inode->i_ino = lower_inode->i_ino;
+	inode->i_mapping->a_ops = &ecryptfs_aops;
+
+	if (S_ISLNK(inode->i_mode))
+		inode->i_op = &ecryptfs_symlink_iops;
+	else if (S_ISDIR(inode->i_mode))
+		inode->i_op = &ecryptfs_dir_iops;
+	else
+		inode->i_op = &ecryptfs_main_iops;
+
+	if (S_ISDIR(inode->i_mode))
+		inode->i_fop = &ecryptfs_dir_fops;
+	else if (special_file(inode->i_mode))
+		init_special_inode(inode, inode->i_mode, inode->i_rdev);
+	else
+		inode->i_fop = &ecryptfs_main_fops;
+
+	return 0;
+}
+
+static struct inode *__ecryptfs_get_inode(struct inode *lower_inode,
+					  struct super_block *sb)
+{
+	struct inode *inode;
+
+	if (lower_inode->i_sb != ecryptfs_superblock_to_lower(sb))
+		return ERR_PTR(-EXDEV);
+	if (!igrab(lower_inode))
+		return ERR_PTR(-ESTALE);
+	inode = iget5_locked(sb, (unsigned long)lower_inode,
+			     ecryptfs_inode_test, ecryptfs_inode_set,
+			     lower_inode);
+	if (!inode) {
+		iput(lower_inode);
+		return ERR_PTR(-EACCES);
+	}
+	if (!(inode->i_state & I_NEW))
+		iput(lower_inode);
+
+	return inode;
+}
+
+struct inode *ecryptfs_get_inode(struct inode *lower_inode,
+				 struct super_block *sb)
+{
+	struct inode *inode = __ecryptfs_get_inode(lower_inode, sb);
+
+	if (!IS_ERR(inode) && (inode->i_state & I_NEW))
+		unlock_new_inode(inode);
+
+	return inode;
+}
+
+/**
+ * ecryptfs_interpose
+ * @lower_dentry: Existing dentry in the lower filesystem
+ * @dentry: ecryptfs' dentry
+ * @sb: ecryptfs's super_block
+ *
+ * Interposes upper and lower dentries.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int ecryptfs_interpose(struct dentry *lower_dentry,
+			      struct dentry *dentry, struct super_block *sb)
+{
+	struct inode *inode = ecryptfs_get_inode(d_inode(lower_dentry), sb);
+
+	if (IS_ERR(inode))
+		return PTR_ERR(inode);
+	d_instantiate(dentry, inode);
+
+	return 0;
+}
+
+static int ecryptfs_do_unlink(struct inode *dir, struct dentry *dentry,
+			      struct inode *inode)
+{
+	struct dentry *lower_dentry;
+	struct inode *lower_dir;
+	int rc;
+
+	rc = lock_parent(dentry, &lower_dentry, &lower_dir);
+	dget(lower_dentry);	// don't even try to make the lower negative
+	if (!rc) {
+		if (d_unhashed(lower_dentry))
+			rc = -EINVAL;
+		else
+			rc = vfs_unlink(&nop_mnt_idmap, lower_dir, lower_dentry,
+					NULL);
+	}
+	if (rc) {
+		printk(KERN_ERR "Error in vfs_unlink; rc = [%d]\n", rc);
+		goto out_unlock;
+	}
+	fsstack_copy_attr_times(dir, lower_dir);
+	set_nlink(inode, ecryptfs_inode_to_lower(inode)->i_nlink);
+	inode_set_ctime_to_ts(inode, inode_get_ctime(dir));
+out_unlock:
+	dput(lower_dentry);
+	inode_unlock(lower_dir);
+	if (!rc)
+		d_drop(dentry);
+	return rc;
+}
+
+/**
+ * ecryptfs_do_create
+ * @directory_inode: inode of the new file's dentry's parent in ecryptfs
+ * @ecryptfs_dentry: New file's dentry in ecryptfs
+ * @mode: The mode of the new file
+ *
+ * Creates the underlying file and the eCryptfs inode which will link to
+ * it. It will also update the eCryptfs directory inode to mimic the
+ * stat of the lower directory inode.
+ *
+ * Returns the new eCryptfs inode on success; an ERR_PTR on error condition
+ */
+static struct inode *
+ecryptfs_do_create(struct inode *directory_inode,
+		   struct dentry *ecryptfs_dentry, umode_t mode)
+{
+	int rc;
+	struct dentry *lower_dentry;
+	struct inode *lower_dir;
+	struct inode *inode;
+
+	rc = lock_parent(ecryptfs_dentry, &lower_dentry, &lower_dir);
+	if (!rc)
+		rc = vfs_create(&nop_mnt_idmap, lower_dir,
+				lower_dentry, mode, true);
+	if (rc) {
+		printk(KERN_ERR "%s: Failure to create dentry in lower fs; "
+		       "rc = [%d]\n", __func__, rc);
+		inode = ERR_PTR(rc);
+		goto out_lock;
+	}
+	inode = __ecryptfs_get_inode(d_inode(lower_dentry),
+				     directory_inode->i_sb);
+	if (IS_ERR(inode)) {
+		vfs_unlink(&nop_mnt_idmap, lower_dir, lower_dentry, NULL);
+		goto out_lock;
+	}
+	fsstack_copy_attr_times(directory_inode, lower_dir);
+	fsstack_copy_inode_size(directory_inode, lower_dir);
+out_lock:
+	inode_unlock(lower_dir);
+	return inode;
+}
+
+/*
+ * ecryptfs_initialize_file
+ *
+ * Cause the file to be changed from a basic empty file to an ecryptfs
+ * file with a header and first data page.
+ *
+ * Returns zero on success
+ */
+int ecryptfs_initialize_file(struct dentry *ecryptfs_dentry,
+			     struct inode *ecryptfs_inode)
+{
+	struct ecryptfs_crypt_stat *crypt_stat =
+		&ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
+	int rc = 0;
+
+	if (S_ISDIR(ecryptfs_inode->i_mode)) {
+		ecryptfs_printk(KERN_DEBUG, "This is a directory\n");
+		crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
+		goto out;
+	}
+	ecryptfs_printk(KERN_DEBUG, "Initializing crypto context\n");
+	rc = ecryptfs_new_file_context(ecryptfs_inode);
+	if (rc) {
+		ecryptfs_printk(KERN_ERR, "Error creating new file "
+				"context; rc = [%d]\n", rc);
+		goto out;
+	}
+	rc = ecryptfs_get_lower_file(ecryptfs_dentry, ecryptfs_inode);
+	if (rc) {
+		printk(KERN_ERR "%s: Error attempting to initialize "
+			"the lower file for the dentry with name "
+			"[%pd]; rc = [%d]\n", __func__,
+			ecryptfs_dentry, rc);
+		goto out;
+	}
+	rc = ecryptfs_write_metadata(ecryptfs_dentry, ecryptfs_inode);
+	if (rc)
+		printk(KERN_ERR "Error writing headers; rc = [%d]\n", rc);
+	ecryptfs_put_lower_file(ecryptfs_inode);
+out:
+	return rc;
+}
+
+/*
+ * ecryptfs_create
+ * @mode: The mode of the new file.
+ *
+ * Creates a new file.
+ *
+ * Returns zero on success; non-zero on error condition
+ */
+static int
+ecryptfs_create(struct mnt_idmap *idmap,
+		struct inode *directory_inode, struct dentry *ecryptfs_dentry,
+		umode_t mode, bool excl)
+{
+	struct inode *ecryptfs_inode;
+	int rc;
+
+	ecryptfs_inode = ecryptfs_do_create(directory_inode, ecryptfs_dentry,
+					    mode);
+	if (IS_ERR(ecryptfs_inode)) {
+		ecryptfs_printk(KERN_WARNING, "Failed to create file in"
+				"lower filesystem\n");
+		rc = PTR_ERR(ecryptfs_inode);
+		goto out;
+	}
+	/* At this point, a file exists on "disk"; we need to make sure
+	 * that this on disk file is prepared to be an ecryptfs file */
+	rc = ecryptfs_initialize_file(ecryptfs_dentry, ecryptfs_inode);
+	if (rc) {
+		ecryptfs_do_unlink(directory_inode, ecryptfs_dentry,
+				   ecryptfs_inode);
+		iget_failed(ecryptfs_inode);
+		goto out;
+	}
+	d_instantiate_new(ecryptfs_dentry, ecryptfs_inode);
+out:
+	return rc;
+}
+
+static int ecryptfs_i_size_read(struct dentry *dentry, struct inode *inode)
+{
+	struct ecryptfs_crypt_stat *crypt_stat;
+	int rc;
+
+	rc = ecryptfs_get_lower_file(dentry, inode);
+	if (rc) {
+		printk(KERN_ERR "%s: Error attempting to initialize "
+			"the lower file for the dentry with name "
+			"[%pd]; rc = [%d]\n", __func__,
+			dentry, rc);
+		return rc;
+	}
+
+	crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
+	/* TODO: lock for crypt_stat comparison */
+	if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED))
+		ecryptfs_set_default_sizes(crypt_stat);
+
+	rc = ecryptfs_read_and_validate_header_region(inode);
+	ecryptfs_put_lower_file(inode);
+	if (rc) {
+		rc = ecryptfs_read_and_validate_xattr_region(dentry, inode);
+		if (!rc)
+			crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
+	}
+
+	/* Must return 0 to allow non-eCryptfs files to be looked up, too */
+	return 0;
+}
+
+/*
+ * ecryptfs_lookup_interpose - Dentry interposition for a lookup
+ */
+static struct dentry *ecryptfs_lookup_interpose(struct dentry *dentry,
+				     struct dentry *lower_dentry)
+{
+	const struct path *path = ecryptfs_dentry_to_lower_path(dentry->d_parent);
+	struct inode *inode, *lower_inode;
+	struct ecryptfs_dentry_info *dentry_info;
+	int rc = 0;
+
+	dentry_info = kmem_cache_alloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
+	if (!dentry_info) {
+		dput(lower_dentry);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	fsstack_copy_attr_atime(d_inode(dentry->d_parent),
+				d_inode(path->dentry));
+	BUG_ON(!d_count(lower_dentry));
+
+	ecryptfs_set_dentry_private(dentry, dentry_info);
+	dentry_info->lower_path.mnt = mntget(path->mnt);
+	dentry_info->lower_path.dentry = lower_dentry;
+
+	/*
+	 * negative dentry can go positive under us here - its parent is not
+	 * locked.  That's OK and that could happen just as we return from
+	 * ecryptfs_lookup() anyway.  Just need to be careful and fetch
+	 * ->d_inode only once - it's not stable here.
+	 */
+	lower_inode = READ_ONCE(lower_dentry->d_inode);
+
+	if (!lower_inode) {
+		/* We want to add because we couldn't find in lower */
+		d_add(dentry, NULL);
+		return NULL;
+	}
+	inode = __ecryptfs_get_inode(lower_inode, dentry->d_sb);
+	if (IS_ERR(inode)) {
+		printk(KERN_ERR "%s: Error interposing; rc = [%ld]\n",
+		       __func__, PTR_ERR(inode));
+		return ERR_CAST(inode);
+	}
+	if (S_ISREG(inode->i_mode)) {
+		rc = ecryptfs_i_size_read(dentry, inode);
+		if (rc) {
+			make_bad_inode(inode);
+			return ERR_PTR(rc);
+		}
+	}
+
+	if (inode->i_state & I_NEW)
+		unlock_new_inode(inode);
+	return d_splice_alias(inode, dentry);
+}
+
+/**
+ * ecryptfs_lookup
+ * @ecryptfs_dir_inode: The eCryptfs directory inode
+ * @ecryptfs_dentry: The eCryptfs dentry that we are looking up
+ * @flags: lookup flags
+ *
+ * Find a file on disk. If the file does not exist, then we'll add it to the
+ * dentry cache and continue on to read it from the disk.
+ */
+static struct dentry *ecryptfs_lookup(struct inode *ecryptfs_dir_inode,
+				      struct dentry *ecryptfs_dentry,
+				      unsigned int flags)
+{
+	char *encrypted_and_encoded_name = NULL;
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
+	struct dentry *lower_dir_dentry, *lower_dentry;
+	const char *name = ecryptfs_dentry->d_name.name;
+	size_t len = ecryptfs_dentry->d_name.len;
+	struct dentry *res;
+	int rc = 0;
+
+	lower_dir_dentry = ecryptfs_dentry_to_lower(ecryptfs_dentry->d_parent);
+
+	mount_crypt_stat = &ecryptfs_superblock_to_private(
+				ecryptfs_dentry->d_sb)->mount_crypt_stat;
+	if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
+		rc = ecryptfs_encrypt_and_encode_filename(
+			&encrypted_and_encoded_name, &len,
+			mount_crypt_stat, name, len);
+		if (rc) {
+			printk(KERN_ERR "%s: Error attempting to encrypt and encode "
+			       "filename; rc = [%d]\n", __func__, rc);
+			return ERR_PTR(rc);
+		}
+		name = encrypted_and_encoded_name;
+	}
+
+	lower_dentry = lookup_one_len_unlocked(name, lower_dir_dentry, len);
+	if (IS_ERR(lower_dentry)) {
+		ecryptfs_printk(KERN_DEBUG, "%s: lookup_one_len() returned "
+				"[%ld] on lower_dentry = [%s]\n", __func__,
+				PTR_ERR(lower_dentry),
+				name);
+		res = ERR_CAST(lower_dentry);
+	} else {
+		res = ecryptfs_lookup_interpose(ecryptfs_dentry, lower_dentry);
+	}
+	kfree(encrypted_and_encoded_name);
+	return res;
+}
+
+static int ecryptfs_link(struct dentry *old_dentry, struct inode *dir,
+			 struct dentry *new_dentry)
+{
+	struct dentry *lower_old_dentry;
+	struct dentry *lower_new_dentry;
+	struct inode *lower_dir;
+	u64 file_size_save;
+	int rc;
+
+	file_size_save = i_size_read(d_inode(old_dentry));
+	lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
+	rc = lock_parent(new_dentry, &lower_new_dentry, &lower_dir);
+	if (!rc)
+		rc = vfs_link(lower_old_dentry, &nop_mnt_idmap, lower_dir,
+			      lower_new_dentry, NULL);
+	if (rc || d_really_is_negative(lower_new_dentry))
+		goto out_lock;
+	rc = ecryptfs_interpose(lower_new_dentry, new_dentry, dir->i_sb);
+	if (rc)
+		goto out_lock;
+	fsstack_copy_attr_times(dir, lower_dir);
+	fsstack_copy_inode_size(dir, lower_dir);
+	set_nlink(d_inode(old_dentry),
+		  ecryptfs_inode_to_lower(d_inode(old_dentry))->i_nlink);
+	i_size_write(d_inode(new_dentry), file_size_save);
+out_lock:
+	inode_unlock(lower_dir);
+	return rc;
+}
+
+static int ecryptfs_unlink(struct inode *dir, struct dentry *dentry)
+{
+	return ecryptfs_do_unlink(dir, dentry, d_inode(dentry));
+}
+
+static int ecryptfs_symlink(struct mnt_idmap *idmap,
+			    struct inode *dir, struct dentry *dentry,
+			    const char *symname)
+{
+	int rc;
+	struct dentry *lower_dentry;
+	struct inode *lower_dir;
+	char *encoded_symname;
+	size_t encoded_symlen;
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat = NULL;
+
+	rc = lock_parent(dentry, &lower_dentry, &lower_dir);
+	if (rc)
+		goto out_lock;
+	mount_crypt_stat = &ecryptfs_superblock_to_private(
+		dir->i_sb)->mount_crypt_stat;
+	rc = ecryptfs_encrypt_and_encode_filename(&encoded_symname,
+						  &encoded_symlen,
+						  mount_crypt_stat, symname,
+						  strlen(symname));
+	if (rc)
+		goto out_lock;
+	rc = vfs_symlink(&nop_mnt_idmap, lower_dir, lower_dentry,
+			 encoded_symname);
+	kfree(encoded_symname);
+	if (rc || d_really_is_negative(lower_dentry))
+		goto out_lock;
+	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
+	if (rc)
+		goto out_lock;
+	fsstack_copy_attr_times(dir, lower_dir);
+	fsstack_copy_inode_size(dir, lower_dir);
+out_lock:
+	inode_unlock(lower_dir);
+	if (d_really_is_negative(dentry))
+		d_drop(dentry);
+	return rc;
+}
+
+static int ecryptfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
+			  struct dentry *dentry, umode_t mode)
+{
+	int rc;
+	struct dentry *lower_dentry;
+	struct inode *lower_dir;
+
+	rc = lock_parent(dentry, &lower_dentry, &lower_dir);
+	if (!rc)
+		rc = vfs_mkdir(&nop_mnt_idmap, lower_dir,
+			       lower_dentry, mode);
+	if (rc || d_really_is_negative(lower_dentry))
+		goto out;
+	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
+	if (rc)
+		goto out;
+	fsstack_copy_attr_times(dir, lower_dir);
+	fsstack_copy_inode_size(dir, lower_dir);
+	set_nlink(dir, lower_dir->i_nlink);
+out:
+	inode_unlock(lower_dir);
+	if (d_really_is_negative(dentry))
+		d_drop(dentry);
+	return rc;
+}
+
+static int ecryptfs_rmdir(struct inode *dir, struct dentry *dentry)
+{
+	struct dentry *lower_dentry;
+	struct inode *lower_dir;
+	int rc;
+
+	rc = lock_parent(dentry, &lower_dentry, &lower_dir);
+	dget(lower_dentry);	// don't even try to make the lower negative
+	if (!rc) {
+		if (d_unhashed(lower_dentry))
+			rc = -EINVAL;
+		else
+			rc = vfs_rmdir(&nop_mnt_idmap, lower_dir, lower_dentry);
+	}
+	if (!rc) {
+		clear_nlink(d_inode(dentry));
+		fsstack_copy_attr_times(dir, lower_dir);
+		set_nlink(dir, lower_dir->i_nlink);
+	}
+	dput(lower_dentry);
+	inode_unlock(lower_dir);
+	if (!rc)
+		d_drop(dentry);
+	return rc;
+}
+
+static int
+ecryptfs_mknod(struct mnt_idmap *idmap, struct inode *dir,
+	       struct dentry *dentry, umode_t mode, dev_t dev)
+{
+	int rc;
+	struct dentry *lower_dentry;
+	struct inode *lower_dir;
+
+	rc = lock_parent(dentry, &lower_dentry, &lower_dir);
+	if (!rc)
+		rc = vfs_mknod(&nop_mnt_idmap, lower_dir,
+			       lower_dentry, mode, dev);
+	if (rc || d_really_is_negative(lower_dentry))
+		goto out;
+	rc = ecryptfs_interpose(lower_dentry, dentry, dir->i_sb);
+	if (rc)
+		goto out;
+	fsstack_copy_attr_times(dir, lower_dir);
+	fsstack_copy_inode_size(dir, lower_dir);
+out:
+	inode_unlock(lower_dir);
+	if (d_really_is_negative(dentry))
+		d_drop(dentry);
+	return rc;
+}
+
+static int
+ecryptfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
+		struct dentry *old_dentry, struct inode *new_dir,
+		struct dentry *new_dentry, unsigned int flags)
+{
+	int rc;
+	struct dentry *lower_old_dentry;
+	struct dentry *lower_new_dentry;
+	struct dentry *lower_old_dir_dentry;
+	struct dentry *lower_new_dir_dentry;
+	struct dentry *trap;
+	struct inode *target_inode;
+	struct renamedata rd = {};
+
+	if (flags)
+		return -EINVAL;
+
+	lower_old_dir_dentry = ecryptfs_dentry_to_lower(old_dentry->d_parent);
+	lower_new_dir_dentry = ecryptfs_dentry_to_lower(new_dentry->d_parent);
+
+	lower_old_dentry = ecryptfs_dentry_to_lower(old_dentry);
+	lower_new_dentry = ecryptfs_dentry_to_lower(new_dentry);
+
+	target_inode = d_inode(new_dentry);
+
+	trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
+	dget(lower_new_dentry);
+	rc = -EINVAL;
+	if (lower_old_dentry->d_parent != lower_old_dir_dentry)
+		goto out_lock;
+	if (lower_new_dentry->d_parent != lower_new_dir_dentry)
+		goto out_lock;
+	if (d_unhashed(lower_old_dentry) || d_unhashed(lower_new_dentry))
+		goto out_lock;
+	/* source should not be ancestor of target */
+	if (trap == lower_old_dentry)
+		goto out_lock;
+	/* target should not be ancestor of source */
+	if (trap == lower_new_dentry) {
+		rc = -ENOTEMPTY;
+		goto out_lock;
+	}
+
+	rd.old_mnt_idmap	= &nop_mnt_idmap;
+	rd.old_dir		= d_inode(lower_old_dir_dentry);
+	rd.old_dentry		= lower_old_dentry;
+	rd.new_mnt_idmap	= &nop_mnt_idmap;
+	rd.new_dir		= d_inode(lower_new_dir_dentry);
+	rd.new_dentry		= lower_new_dentry;
+	rc = vfs_rename(&rd);
+	if (rc)
+		goto out_lock;
+	if (target_inode)
+		fsstack_copy_attr_all(target_inode,
+				      ecryptfs_inode_to_lower(target_inode));
+	fsstack_copy_attr_all(new_dir, d_inode(lower_new_dir_dentry));
+	if (new_dir != old_dir)
+		fsstack_copy_attr_all(old_dir, d_inode(lower_old_dir_dentry));
+out_lock:
+	dput(lower_new_dentry);
+	unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
+	return rc;
+}
+
+static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
+{
+	DEFINE_DELAYED_CALL(done);
+	struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
+	const char *link;
+	char *buf;
+	int rc;
+
+	link = vfs_get_link(lower_dentry, &done);
+	if (IS_ERR(link))
+		return ERR_CAST(link);
+
+	rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
+						  link, strlen(link));
+	do_delayed_call(&done);
+	if (rc)
+		return ERR_PTR(rc);
+
+	return buf;
+}
+
+static const char *ecryptfs_get_link(struct dentry *dentry,
+				     struct inode *inode,
+				     struct delayed_call *done)
+{
+	size_t len;
+	char *buf;
+
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
+
+	buf = ecryptfs_readlink_lower(dentry, &len);
+	if (IS_ERR(buf))
+		return buf;
+	fsstack_copy_attr_atime(d_inode(dentry),
+				d_inode(ecryptfs_dentry_to_lower(dentry)));
+	buf[len] = '\0';
+	set_delayed_call(done, kfree_link, buf);
+	return buf;
+}
+
+/**
+ * upper_size_to_lower_size
+ * @crypt_stat: Crypt_stat associated with file
+ * @upper_size: Size of the upper file
+ *
+ * Calculate the required size of the lower file based on the
+ * specified size of the upper file. This calculation is based on the
+ * number of headers in the underlying file and the extent size.
+ *
+ * Returns Calculated size of the lower file.
+ */
+static loff_t
+upper_size_to_lower_size(struct ecryptfs_crypt_stat *crypt_stat,
+			 loff_t upper_size)
+{
+	loff_t lower_size;
+
+	lower_size = ecryptfs_lower_header_size(crypt_stat);
+	if (upper_size != 0) {
+		loff_t num_extents;
+
+		num_extents = upper_size >> crypt_stat->extent_shift;
+		if (upper_size & ~crypt_stat->extent_mask)
+			num_extents++;
+		lower_size += (num_extents * crypt_stat->extent_size);
+	}
+	return lower_size;
+}
+
+/**
+ * truncate_upper
+ * @dentry: The ecryptfs layer dentry
+ * @ia: Address of the ecryptfs inode's attributes
+ * @lower_ia: Address of the lower inode's attributes
+ *
+ * Function to handle truncations modifying the size of the file. Note
+ * that the file sizes are interpolated. When expanding, we are simply
+ * writing strings of 0's out. When truncating, we truncate the upper
+ * inode and update the lower_ia according to the page index
+ * interpolations. If ATTR_SIZE is set in lower_ia->ia_valid upon return,
+ * the caller must use lower_ia in a call to notify_change() to perform
+ * the truncation of the lower inode.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int truncate_upper(struct dentry *dentry, struct iattr *ia,
+			  struct iattr *lower_ia)
+{
+	int rc = 0;
+	struct inode *inode = d_inode(dentry);
+	struct ecryptfs_crypt_stat *crypt_stat;
+	loff_t i_size = i_size_read(inode);
+	loff_t lower_size_before_truncate;
+	loff_t lower_size_after_truncate;
+
+	if (unlikely((ia->ia_size == i_size))) {
+		lower_ia->ia_valid &= ~ATTR_SIZE;
+		return 0;
+	}
+	rc = ecryptfs_get_lower_file(dentry, inode);
+	if (rc)
+		return rc;
+	crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
+	/* Switch on growing or shrinking file */
+	if (ia->ia_size > i_size) {
+		char zero[] = { 0x00 };
+
+		lower_ia->ia_valid &= ~ATTR_SIZE;
+		/* Write a single 0 at the last position of the file;
+		 * this triggers code that will fill in 0's throughout
+		 * the intermediate portion of the previous end of the
+		 * file and the new and of the file */
+		rc = ecryptfs_write(inode, zero,
+				    (ia->ia_size - 1), 1);
+	} else { /* ia->ia_size < i_size_read(inode) */
+		/* We're chopping off all the pages down to the page
+		 * in which ia->ia_size is located. Fill in the end of
+		 * that page from (ia->ia_size & ~PAGE_MASK) to
+		 * PAGE_SIZE with zeros. */
+		size_t num_zeros = (PAGE_SIZE
+				    - (ia->ia_size & ~PAGE_MASK));
+
+		if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
+			truncate_setsize(inode, ia->ia_size);
+			lower_ia->ia_size = ia->ia_size;
+			lower_ia->ia_valid |= ATTR_SIZE;
+			goto out;
+		}
+		if (num_zeros) {
+			char *zeros_virt;
+
+			zeros_virt = kzalloc(num_zeros, GFP_KERNEL);
+			if (!zeros_virt) {
+				rc = -ENOMEM;
+				goto out;
+			}
+			rc = ecryptfs_write(inode, zeros_virt,
+					    ia->ia_size, num_zeros);
+			kfree(zeros_virt);
+			if (rc) {
+				printk(KERN_ERR "Error attempting to zero out "
+				       "the remainder of the end page on "
+				       "reducing truncate; rc = [%d]\n", rc);
+				goto out;
+			}
+		}
+		truncate_setsize(inode, ia->ia_size);
+		rc = ecryptfs_write_inode_size_to_metadata(inode);
+		if (rc) {
+			printk(KERN_ERR	"Problem with "
+			       "ecryptfs_write_inode_size_to_metadata; "
+			       "rc = [%d]\n", rc);
+			goto out;
+		}
+		/* We are reducing the size of the ecryptfs file, and need to
+		 * know if we need to reduce the size of the lower file. */
+		lower_size_before_truncate =
+		    upper_size_to_lower_size(crypt_stat, i_size);
+		lower_size_after_truncate =
+		    upper_size_to_lower_size(crypt_stat, ia->ia_size);
+		if (lower_size_after_truncate < lower_size_before_truncate) {
+			lower_ia->ia_size = lower_size_after_truncate;
+			lower_ia->ia_valid |= ATTR_SIZE;
+		} else
+			lower_ia->ia_valid &= ~ATTR_SIZE;
+	}
+out:
+	ecryptfs_put_lower_file(inode);
+	return rc;
+}
+
+static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset)
+{
+	struct ecryptfs_crypt_stat *crypt_stat;
+	loff_t lower_oldsize, lower_newsize;
+
+	crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat;
+	lower_oldsize = upper_size_to_lower_size(crypt_stat,
+						 i_size_read(inode));
+	lower_newsize = upper_size_to_lower_size(crypt_stat, offset);
+	if (lower_newsize > lower_oldsize) {
+		/*
+		 * The eCryptfs inode and the new *lower* size are mixed here
+		 * because we may not have the lower i_mutex held and/or it may
+		 * not be appropriate to call inode_newsize_ok() with inodes
+		 * from other filesystems.
+		 */
+		return inode_newsize_ok(inode, lower_newsize);
+	}
+
+	return 0;
+}
+
+/**
+ * ecryptfs_truncate
+ * @dentry: The ecryptfs layer dentry
+ * @new_length: The length to expand the file to
+ *
+ * Simple function that handles the truncation of an eCryptfs inode and
+ * its corresponding lower inode.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int ecryptfs_truncate(struct dentry *dentry, loff_t new_length)
+{
+	struct iattr ia = { .ia_valid = ATTR_SIZE, .ia_size = new_length };
+	struct iattr lower_ia = { .ia_valid = 0 };
+	int rc;
+
+	rc = ecryptfs_inode_newsize_ok(d_inode(dentry), new_length);
+	if (rc)
+		return rc;
+
+	rc = truncate_upper(dentry, &ia, &lower_ia);
+	if (!rc && lower_ia.ia_valid & ATTR_SIZE) {
+		struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
+
+		inode_lock(d_inode(lower_dentry));
+		rc = notify_change(&nop_mnt_idmap, lower_dentry,
+				   &lower_ia, NULL);
+		inode_unlock(d_inode(lower_dentry));
+	}
+	return rc;
+}
+
+static int
+ecryptfs_permission(struct mnt_idmap *idmap, struct inode *inode,
+		    int mask)
+{
+	return inode_permission(&nop_mnt_idmap,
+				ecryptfs_inode_to_lower(inode), mask);
+}
+
+/**
+ * ecryptfs_setattr
+ * @idmap: idmap of the target mount
+ * @dentry: dentry handle to the inode to modify
+ * @ia: Structure with flags of what to change and values
+ *
+ * Updates the metadata of an inode. If the update is to the size
+ * i.e. truncation, then ecryptfs_truncate will handle the size modification
+ * of both the ecryptfs inode and the lower inode.
+ *
+ * All other metadata changes will be passed right to the lower filesystem,
+ * and we will just update our inode to look like the lower.
+ */
+static int ecryptfs_setattr(struct mnt_idmap *idmap,
+			    struct dentry *dentry, struct iattr *ia)
+{
+	int rc = 0;
+	struct dentry *lower_dentry;
+	struct iattr lower_ia;
+	struct inode *inode;
+	struct inode *lower_inode;
+	struct ecryptfs_crypt_stat *crypt_stat;
+
+	crypt_stat = &ecryptfs_inode_to_private(d_inode(dentry))->crypt_stat;
+	if (!(crypt_stat->flags & ECRYPTFS_STRUCT_INITIALIZED)) {
+		rc = ecryptfs_init_crypt_stat(crypt_stat);
+		if (rc)
+			return rc;
+	}
+	inode = d_inode(dentry);
+	lower_inode = ecryptfs_inode_to_lower(inode);
+	lower_dentry = ecryptfs_dentry_to_lower(dentry);
+	mutex_lock(&crypt_stat->cs_mutex);
+	if (d_is_dir(dentry))
+		crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
+	else if (d_is_reg(dentry)
+		 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
+		     || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
+		struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
+
+		mount_crypt_stat = &ecryptfs_superblock_to_private(
+			dentry->d_sb)->mount_crypt_stat;
+		rc = ecryptfs_get_lower_file(dentry, inode);
+		if (rc) {
+			mutex_unlock(&crypt_stat->cs_mutex);
+			goto out;
+		}
+		rc = ecryptfs_read_metadata(dentry);
+		ecryptfs_put_lower_file(inode);
+		if (rc) {
+			if (!(mount_crypt_stat->flags
+			      & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)) {
+				rc = -EIO;
+				printk(KERN_WARNING "Either the lower file "
+				       "is not in a valid eCryptfs format, "
+				       "or the key could not be retrieved. "
+				       "Plaintext passthrough mode is not "
+				       "enabled; returning -EIO\n");
+				mutex_unlock(&crypt_stat->cs_mutex);
+				goto out;
+			}
+			rc = 0;
+			crypt_stat->flags &= ~(ECRYPTFS_I_SIZE_INITIALIZED
+					       | ECRYPTFS_ENCRYPTED);
+		}
+	}
+	mutex_unlock(&crypt_stat->cs_mutex);
+
+	rc = setattr_prepare(&nop_mnt_idmap, dentry, ia);
+	if (rc)
+		goto out;
+	if (ia->ia_valid & ATTR_SIZE) {
+		rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size);
+		if (rc)
+			goto out;
+	}
+
+	memcpy(&lower_ia, ia, sizeof(lower_ia));
+	if (ia->ia_valid & ATTR_FILE)
+		lower_ia.ia_file = ecryptfs_file_to_lower(ia->ia_file);
+	if (ia->ia_valid & ATTR_SIZE) {
+		rc = truncate_upper(dentry, ia, &lower_ia);
+		if (rc < 0)
+			goto out;
+	}
+
+	/*
+	 * mode change is for clearing setuid/setgid bits. Allow lower fs
+	 * to interpret this in its own way.
+	 */
+	if (lower_ia.ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
+		lower_ia.ia_valid &= ~ATTR_MODE;
+
+	inode_lock(d_inode(lower_dentry));
+	rc = notify_change(&nop_mnt_idmap, lower_dentry, &lower_ia, NULL);
+	inode_unlock(d_inode(lower_dentry));
+out:
+	fsstack_copy_attr_all(inode, lower_inode);
+	return rc;
+}
+
+static int ecryptfs_getattr_link(struct mnt_idmap *idmap,
+				 const struct path *path, struct kstat *stat,
+				 u32 request_mask, unsigned int flags)
+{
+	struct dentry *dentry = path->dentry;
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
+	int rc = 0;
+
+	mount_crypt_stat = &ecryptfs_superblock_to_private(
+						dentry->d_sb)->mount_crypt_stat;
+	generic_fillattr(&nop_mnt_idmap, request_mask, d_inode(dentry), stat);
+	if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES) {
+		char *target;
+		size_t targetsiz;
+
+		target = ecryptfs_readlink_lower(dentry, &targetsiz);
+		if (!IS_ERR(target)) {
+			kfree(target);
+			stat->size = targetsiz;
+		} else {
+			rc = PTR_ERR(target);
+		}
+	}
+	return rc;
+}
+
+static int ecryptfs_do_getattr(const struct path *path, struct kstat *stat,
+			       u32 request_mask, unsigned int flags)
+{
+	if (flags & AT_GETATTR_NOSEC)
+		return vfs_getattr_nosec(path, stat, request_mask, flags);
+	return vfs_getattr(path, stat, request_mask, flags);
+}
+
+static int ecryptfs_getattr(struct mnt_idmap *idmap,
+			    const struct path *path, struct kstat *stat,
+			    u32 request_mask, unsigned int flags)
+{
+	struct dentry *dentry = path->dentry;
+	struct kstat lower_stat;
+	int rc;
+
+	rc = ecryptfs_do_getattr(ecryptfs_dentry_to_lower_path(dentry),
+				 &lower_stat, request_mask, flags);
+	if (!rc) {
+		fsstack_copy_attr_all(d_inode(dentry),
+				      ecryptfs_inode_to_lower(d_inode(dentry)));
+		generic_fillattr(&nop_mnt_idmap, request_mask,
+				 d_inode(dentry), stat);
+		stat->blocks = lower_stat.blocks;
+	}
+	return rc;
+}
+
+int
+ecryptfs_setxattr(struct dentry *dentry, struct inode *inode,
+		  const char *name, const void *value,
+		  size_t size, int flags)
+{
+	int rc;
+	struct dentry *lower_dentry;
+	struct inode *lower_inode;
+
+	lower_dentry = ecryptfs_dentry_to_lower(dentry);
+	lower_inode = d_inode(lower_dentry);
+	if (!(lower_inode->i_opflags & IOP_XATTR)) {
+		rc = -EOPNOTSUPP;
+		goto out;
+	}
+	inode_lock(lower_inode);
+	rc = __vfs_setxattr_locked(&nop_mnt_idmap, lower_dentry, name, value, size, flags, NULL);
+	inode_unlock(lower_inode);
+	if (!rc && inode)
+		fsstack_copy_attr_all(inode, lower_inode);
+out:
+	return rc;
+}
+
+ssize_t
+ecryptfs_getxattr_lower(struct dentry *lower_dentry, struct inode *lower_inode,
+			const char *name, void *value, size_t size)
+{
+	int rc;
+
+	if (!(lower_inode->i_opflags & IOP_XATTR)) {
+		rc = -EOPNOTSUPP;
+		goto out;
+	}
+	inode_lock(lower_inode);
+	rc = __vfs_getxattr(lower_dentry, lower_inode, name, value, size);
+	inode_unlock(lower_inode);
+out:
+	return rc;
+}
+
+static ssize_t
+ecryptfs_getxattr(struct dentry *dentry, struct inode *inode,
+		  const char *name, void *value, size_t size)
+{
+	return ecryptfs_getxattr_lower(ecryptfs_dentry_to_lower(dentry),
+				       ecryptfs_inode_to_lower(inode),
+				       name, value, size);
+}
+
+static ssize_t
+ecryptfs_listxattr(struct dentry *dentry, char *list, size_t size)
+{
+	int rc = 0;
+	struct dentry *lower_dentry;
+
+	lower_dentry = ecryptfs_dentry_to_lower(dentry);
+	if (!d_inode(lower_dentry)->i_op->listxattr) {
+		rc = -EOPNOTSUPP;
+		goto out;
+	}
+	inode_lock(d_inode(lower_dentry));
+	rc = d_inode(lower_dentry)->i_op->listxattr(lower_dentry, list, size);
+	inode_unlock(d_inode(lower_dentry));
+out:
+	return rc;
+}
+
+static int ecryptfs_removexattr(struct dentry *dentry, struct inode *inode,
+				const char *name)
+{
+	int rc;
+	struct dentry *lower_dentry;
+	struct inode *lower_inode;
+
+	lower_dentry = ecryptfs_dentry_to_lower(dentry);
+	lower_inode = ecryptfs_inode_to_lower(inode);
+	if (!(lower_inode->i_opflags & IOP_XATTR)) {
+		rc = -EOPNOTSUPP;
+		goto out;
+	}
+	inode_lock(lower_inode);
+	rc = __vfs_removexattr(&nop_mnt_idmap, lower_dentry, name);
+	inode_unlock(lower_inode);
+out:
+	return rc;
+}
+
+static int ecryptfs_fileattr_get(struct dentry *dentry, struct fileattr *fa)
+{
+	return vfs_fileattr_get(ecryptfs_dentry_to_lower(dentry), fa);
+}
+
+static int ecryptfs_fileattr_set(struct mnt_idmap *idmap,
+				 struct dentry *dentry, struct fileattr *fa)
+{
+	struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
+	int rc;
+
+	rc = vfs_fileattr_set(&nop_mnt_idmap, lower_dentry, fa);
+	fsstack_copy_attr_all(d_inode(dentry), d_inode(lower_dentry));
+
+	return rc;
+}
+
+static struct posix_acl *ecryptfs_get_acl(struct mnt_idmap *idmap,
+					  struct dentry *dentry, int type)
+{
+	return vfs_get_acl(idmap, ecryptfs_dentry_to_lower(dentry),
+			   posix_acl_xattr_name(type));
+}
+
+static int ecryptfs_set_acl(struct mnt_idmap *idmap,
+			    struct dentry *dentry, struct posix_acl *acl,
+			    int type)
+{
+	int rc;
+	struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
+	struct inode *lower_inode = d_inode(lower_dentry);
+
+	rc = vfs_set_acl(&nop_mnt_idmap, lower_dentry,
+			 posix_acl_xattr_name(type), acl);
+	if (!rc)
+		fsstack_copy_attr_all(d_inode(dentry), lower_inode);
+	return rc;
+}
+
+const struct inode_operations ecryptfs_symlink_iops = {
+	.get_link = ecryptfs_get_link,
+	.permission = ecryptfs_permission,
+	.setattr = ecryptfs_setattr,
+	.getattr = ecryptfs_getattr_link,
+	.listxattr = ecryptfs_listxattr,
+};
+
+const struct inode_operations ecryptfs_dir_iops = {
+	.create = ecryptfs_create,
+	.lookup = ecryptfs_lookup,
+	.link = ecryptfs_link,
+	.unlink = ecryptfs_unlink,
+	.symlink = ecryptfs_symlink,
+	.mkdir = ecryptfs_mkdir,
+	.rmdir = ecryptfs_rmdir,
+	.mknod = ecryptfs_mknod,
+	.rename = ecryptfs_rename,
+	.permission = ecryptfs_permission,
+	.setattr = ecryptfs_setattr,
+	.listxattr = ecryptfs_listxattr,
+	.fileattr_get = ecryptfs_fileattr_get,
+	.fileattr_set = ecryptfs_fileattr_set,
+	.get_acl = ecryptfs_get_acl,
+	.set_acl = ecryptfs_set_acl,
+};
+
+const struct inode_operations ecryptfs_main_iops = {
+	.permission = ecryptfs_permission,
+	.setattr = ecryptfs_setattr,
+	.getattr = ecryptfs_getattr,
+	.listxattr = ecryptfs_listxattr,
+	.fileattr_get = ecryptfs_fileattr_get,
+	.fileattr_set = ecryptfs_fileattr_set,
+	.get_acl = ecryptfs_get_acl,
+	.set_acl = ecryptfs_set_acl,
+};
+
+static int ecryptfs_xattr_get(const struct xattr_handler *handler,
+			      struct dentry *dentry, struct inode *inode,
+			      const char *name, void *buffer, size_t size)
+{
+	return ecryptfs_getxattr(dentry, inode, name, buffer, size);
+}
+
+static int ecryptfs_xattr_set(const struct xattr_handler *handler,
+			      struct mnt_idmap *idmap,
+			      struct dentry *dentry, struct inode *inode,
+			      const char *name, const void *value, size_t size,
+			      int flags)
+{
+	if (value)
+		return ecryptfs_setxattr(dentry, inode, name, value, size, flags);
+	else {
+		BUG_ON(flags != XATTR_REPLACE);
+		return ecryptfs_removexattr(dentry, inode, name);
+	}
+}
+
+static const struct xattr_handler ecryptfs_xattr_handler = {
+	.prefix = "",  /* match anything */
+	.get = ecryptfs_xattr_get,
+	.set = ecryptfs_xattr_set,
+};
+
+const struct xattr_handler *ecryptfs_xattr_handlers[] = {
+	&ecryptfs_xattr_handler,
+	NULL
+};
diff --git a/fs/ecryptfs/keystore.c b/fs/ecryptfs/keystore.c
new file mode 100644
index 000000000..3fe41964c
--- /dev/null
+++ b/fs/ecryptfs/keystore.c
@@ -0,0 +1,2531 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * eCryptfs: Linux filesystem encryption layer
+ * In-kernel key management code.  Includes functions to parse and
+ * write authentication token-related packets with the underlying
+ * file.
+ *
+ * Copyright (C) 2004-2006 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
+ *              Michael C. Thompson <mcthomps@us.ibm.com>
+ *              Trevor S. Highland <trevor.highland@gmail.com>
+ */
+
+#include <crypto/hash.h>
+#include <crypto/skcipher.h>
+#include <linux/string.h>
+#include <linux/pagemap.h>
+#include <linux/key.h>
+#include <linux/random.h>
+#include <linux/scatterlist.h>
+#include <linux/slab.h>
+#include "ecryptfs_kernel.h"
+
+/*
+ * request_key returned an error instead of a valid key address;
+ * determine the type of error, make appropriate log entries, and
+ * return an error code.
+ */
+static int process_request_key_err(long err_code)
+{
+	int rc = 0;
+
+	switch (err_code) {
+	case -ENOKEY:
+		ecryptfs_printk(KERN_WARNING, "No key\n");
+		rc = -ENOENT;
+		break;
+	case -EKEYEXPIRED:
+		ecryptfs_printk(KERN_WARNING, "Key expired\n");
+		rc = -ETIME;
+		break;
+	case -EKEYREVOKED:
+		ecryptfs_printk(KERN_WARNING, "Key revoked\n");
+		rc = -EINVAL;
+		break;
+	default:
+		ecryptfs_printk(KERN_WARNING, "Unknown error code: "
+				"[0x%.16lx]\n", err_code);
+		rc = -EINVAL;
+	}
+	return rc;
+}
+
+static int process_find_global_auth_tok_for_sig_err(int err_code)
+{
+	int rc = err_code;
+
+	switch (err_code) {
+	case -ENOENT:
+		ecryptfs_printk(KERN_WARNING, "Missing auth tok\n");
+		break;
+	case -EINVAL:
+		ecryptfs_printk(KERN_WARNING, "Invalid auth tok\n");
+		break;
+	default:
+		rc = process_request_key_err(err_code);
+		break;
+	}
+	return rc;
+}
+
+/**
+ * ecryptfs_parse_packet_length
+ * @data: Pointer to memory containing length at offset
+ * @size: This function writes the decoded size to this memory
+ *        address; zero on error
+ * @length_size: The number of bytes occupied by the encoded length
+ *
+ * Returns zero on success; non-zero on error
+ */
+int ecryptfs_parse_packet_length(unsigned char *data, size_t *size,
+				 size_t *length_size)
+{
+	int rc = 0;
+
+	(*length_size) = 0;
+	(*size) = 0;
+	if (data[0] < 192) {
+		/* One-byte length */
+		(*size) = data[0];
+		(*length_size) = 1;
+	} else if (data[0] < 224) {
+		/* Two-byte length */
+		(*size) = (data[0] - 192) * 256;
+		(*size) += data[1] + 192;
+		(*length_size) = 2;
+	} else if (data[0] == 255) {
+		/* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
+		ecryptfs_printk(KERN_ERR, "Five-byte packet length not "
+				"supported\n");
+		rc = -EINVAL;
+		goto out;
+	} else {
+		ecryptfs_printk(KERN_ERR, "Error parsing packet length\n");
+		rc = -EINVAL;
+		goto out;
+	}
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_write_packet_length
+ * @dest: The byte array target into which to write the length. Must
+ *        have at least ECRYPTFS_MAX_PKT_LEN_SIZE bytes allocated.
+ * @size: The length to write.
+ * @packet_size_length: The number of bytes used to encode the packet
+ *                      length is written to this address.
+ *
+ * Returns zero on success; non-zero on error.
+ */
+int ecryptfs_write_packet_length(char *dest, size_t size,
+				 size_t *packet_size_length)
+{
+	int rc = 0;
+
+	if (size < 192) {
+		dest[0] = size;
+		(*packet_size_length) = 1;
+	} else if (size < 65536) {
+		dest[0] = (((size - 192) / 256) + 192);
+		dest[1] = ((size - 192) % 256);
+		(*packet_size_length) = 2;
+	} else {
+		/* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */
+		rc = -EINVAL;
+		ecryptfs_printk(KERN_WARNING,
+				"Unsupported packet size: [%zd]\n", size);
+	}
+	return rc;
+}
+
+static int
+write_tag_64_packet(char *signature, struct ecryptfs_session_key *session_key,
+		    char **packet, size_t *packet_len)
+{
+	size_t i = 0;
+	size_t data_len;
+	size_t packet_size_len;
+	char *message;
+	int rc;
+
+	/*
+	 *              ***** TAG 64 Packet Format *****
+	 *    | Content Type                       | 1 byte       |
+	 *    | Key Identifier Size                | 1 or 2 bytes |
+	 *    | Key Identifier                     | arbitrary    |
+	 *    | Encrypted File Encryption Key Size | 1 or 2 bytes |
+	 *    | Encrypted File Encryption Key      | arbitrary    |
+	 */
+	data_len = (5 + ECRYPTFS_SIG_SIZE_HEX
+		    + session_key->encrypted_key_size);
+	*packet = kmalloc(data_len, GFP_KERNEL);
+	message = *packet;
+	if (!message) {
+		ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
+		rc = -ENOMEM;
+		goto out;
+	}
+	message[i++] = ECRYPTFS_TAG_64_PACKET_TYPE;
+	rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
+					  &packet_size_len);
+	if (rc) {
+		ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
+				"header; cannot generate packet length\n");
+		goto out;
+	}
+	i += packet_size_len;
+	memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
+	i += ECRYPTFS_SIG_SIZE_HEX;
+	rc = ecryptfs_write_packet_length(&message[i],
+					  session_key->encrypted_key_size,
+					  &packet_size_len);
+	if (rc) {
+		ecryptfs_printk(KERN_ERR, "Error generating tag 64 packet "
+				"header; cannot generate packet length\n");
+		goto out;
+	}
+	i += packet_size_len;
+	memcpy(&message[i], session_key->encrypted_key,
+	       session_key->encrypted_key_size);
+	i += session_key->encrypted_key_size;
+	*packet_len = i;
+out:
+	return rc;
+}
+
+static int
+parse_tag_65_packet(struct ecryptfs_session_key *session_key, u8 *cipher_code,
+		    struct ecryptfs_message *msg)
+{
+	size_t i = 0;
+	char *data;
+	size_t data_len;
+	size_t m_size;
+	size_t message_len;
+	u16 checksum = 0;
+	u16 expected_checksum = 0;
+	int rc;
+
+	/*
+	 *              ***** TAG 65 Packet Format *****
+	 *         | Content Type             | 1 byte       |
+	 *         | Status Indicator         | 1 byte       |
+	 *         | File Encryption Key Size | 1 or 2 bytes |
+	 *         | File Encryption Key      | arbitrary    |
+	 */
+	message_len = msg->data_len;
+	data = msg->data;
+	if (message_len < 4) {
+		rc = -EIO;
+		goto out;
+	}
+	if (data[i++] != ECRYPTFS_TAG_65_PACKET_TYPE) {
+		ecryptfs_printk(KERN_ERR, "Type should be ECRYPTFS_TAG_65\n");
+		rc = -EIO;
+		goto out;
+	}
+	if (data[i++]) {
+		ecryptfs_printk(KERN_ERR, "Status indicator has non-zero value "
+				"[%d]\n", data[i-1]);
+		rc = -EIO;
+		goto out;
+	}
+	rc = ecryptfs_parse_packet_length(&data[i], &m_size, &data_len);
+	if (rc) {
+		ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
+				"rc = [%d]\n", rc);
+		goto out;
+	}
+	i += data_len;
+	if (message_len < (i + m_size)) {
+		ecryptfs_printk(KERN_ERR, "The message received from ecryptfsd "
+				"is shorter than expected\n");
+		rc = -EIO;
+		goto out;
+	}
+	if (m_size < 3) {
+		ecryptfs_printk(KERN_ERR,
+				"The decrypted key is not long enough to "
+				"include a cipher code and checksum\n");
+		rc = -EIO;
+		goto out;
+	}
+	*cipher_code = data[i++];
+	/* The decrypted key includes 1 byte cipher code and 2 byte checksum */
+	session_key->decrypted_key_size = m_size - 3;
+	if (session_key->decrypted_key_size > ECRYPTFS_MAX_KEY_BYTES) {
+		ecryptfs_printk(KERN_ERR, "key_size [%d] larger than "
+				"the maximum key size [%d]\n",
+				session_key->decrypted_key_size,
+				ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
+		rc = -EIO;
+		goto out;
+	}
+	memcpy(session_key->decrypted_key, &data[i],
+	       session_key->decrypted_key_size);
+	i += session_key->decrypted_key_size;
+	expected_checksum += (unsigned char)(data[i++]) << 8;
+	expected_checksum += (unsigned char)(data[i++]);
+	for (i = 0; i < session_key->decrypted_key_size; i++)
+		checksum += session_key->decrypted_key[i];
+	if (expected_checksum != checksum) {
+		ecryptfs_printk(KERN_ERR, "Invalid checksum for file "
+				"encryption  key; expected [%x]; calculated "
+				"[%x]\n", expected_checksum, checksum);
+		rc = -EIO;
+	}
+out:
+	return rc;
+}
+
+
+static int
+write_tag_66_packet(char *signature, u8 cipher_code,
+		    struct ecryptfs_crypt_stat *crypt_stat, char **packet,
+		    size_t *packet_len)
+{
+	size_t i = 0;
+	size_t j;
+	size_t data_len;
+	size_t checksum = 0;
+	size_t packet_size_len;
+	char *message;
+	int rc;
+
+	/*
+	 *              ***** TAG 66 Packet Format *****
+	 *         | Content Type             | 1 byte       |
+	 *         | Key Identifier Size      | 1 or 2 bytes |
+	 *         | Key Identifier           | arbitrary    |
+	 *         | File Encryption Key Size | 1 or 2 bytes |
+	 *         | File Encryption Key      | arbitrary    |
+	 */
+	data_len = (5 + ECRYPTFS_SIG_SIZE_HEX + crypt_stat->key_size);
+	*packet = kmalloc(data_len, GFP_KERNEL);
+	message = *packet;
+	if (!message) {
+		ecryptfs_printk(KERN_ERR, "Unable to allocate memory\n");
+		rc = -ENOMEM;
+		goto out;
+	}
+	message[i++] = ECRYPTFS_TAG_66_PACKET_TYPE;
+	rc = ecryptfs_write_packet_length(&message[i], ECRYPTFS_SIG_SIZE_HEX,
+					  &packet_size_len);
+	if (rc) {
+		ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
+				"header; cannot generate packet length\n");
+		goto out;
+	}
+	i += packet_size_len;
+	memcpy(&message[i], signature, ECRYPTFS_SIG_SIZE_HEX);
+	i += ECRYPTFS_SIG_SIZE_HEX;
+	/* The encrypted key includes 1 byte cipher code and 2 byte checksum */
+	rc = ecryptfs_write_packet_length(&message[i], crypt_stat->key_size + 3,
+					  &packet_size_len);
+	if (rc) {
+		ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet "
+				"header; cannot generate packet length\n");
+		goto out;
+	}
+	i += packet_size_len;
+	message[i++] = cipher_code;
+	memcpy(&message[i], crypt_stat->key, crypt_stat->key_size);
+	i += crypt_stat->key_size;
+	for (j = 0; j < crypt_stat->key_size; j++)
+		checksum += crypt_stat->key[j];
+	message[i++] = (checksum / 256) % 256;
+	message[i++] = (checksum % 256);
+	*packet_len = i;
+out:
+	return rc;
+}
+
+static int
+parse_tag_67_packet(struct ecryptfs_key_record *key_rec,
+		    struct ecryptfs_message *msg)
+{
+	size_t i = 0;
+	char *data;
+	size_t data_len;
+	size_t message_len;
+	int rc;
+
+	/*
+	 *              ***** TAG 65 Packet Format *****
+	 *    | Content Type                       | 1 byte       |
+	 *    | Status Indicator                   | 1 byte       |
+	 *    | Encrypted File Encryption Key Size | 1 or 2 bytes |
+	 *    | Encrypted File Encryption Key      | arbitrary    |
+	 */
+	message_len = msg->data_len;
+	data = msg->data;
+	/* verify that everything through the encrypted FEK size is present */
+	if (message_len < 4) {
+		rc = -EIO;
+		printk(KERN_ERR "%s: message_len is [%zd]; minimum acceptable "
+		       "message length is [%d]\n", __func__, message_len, 4);
+		goto out;
+	}
+	if (data[i++] != ECRYPTFS_TAG_67_PACKET_TYPE) {
+		rc = -EIO;
+		printk(KERN_ERR "%s: Type should be ECRYPTFS_TAG_67\n",
+		       __func__);
+		goto out;
+	}
+	if (data[i++]) {
+		rc = -EIO;
+		printk(KERN_ERR "%s: Status indicator has non zero "
+		       "value [%d]\n", __func__, data[i-1]);
+
+		goto out;
+	}
+	rc = ecryptfs_parse_packet_length(&data[i], &key_rec->enc_key_size,
+					  &data_len);
+	if (rc) {
+		ecryptfs_printk(KERN_WARNING, "Error parsing packet length; "
+				"rc = [%d]\n", rc);
+		goto out;
+	}
+	i += data_len;
+	if (message_len < (i + key_rec->enc_key_size)) {
+		rc = -EIO;
+		printk(KERN_ERR "%s: message_len [%zd]; max len is [%zd]\n",
+		       __func__, message_len, (i + key_rec->enc_key_size));
+		goto out;
+	}
+	if (key_rec->enc_key_size > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
+		rc = -EIO;
+		printk(KERN_ERR "%s: Encrypted key_size [%zd] larger than "
+		       "the maximum key size [%d]\n", __func__,
+		       key_rec->enc_key_size,
+		       ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES);
+		goto out;
+	}
+	memcpy(key_rec->enc_key, &data[i], key_rec->enc_key_size);
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_verify_version
+ * @version: The version number to confirm
+ *
+ * Returns zero on good version; non-zero otherwise
+ */
+static int ecryptfs_verify_version(u16 version)
+{
+	int rc = 0;
+	unsigned char major;
+	unsigned char minor;
+
+	major = ((version >> 8) & 0xFF);
+	minor = (version & 0xFF);
+	if (major != ECRYPTFS_VERSION_MAJOR) {
+		ecryptfs_printk(KERN_ERR, "Major version number mismatch. "
+				"Expected [%d]; got [%d]\n",
+				ECRYPTFS_VERSION_MAJOR, major);
+		rc = -EINVAL;
+		goto out;
+	}
+	if (minor != ECRYPTFS_VERSION_MINOR) {
+		ecryptfs_printk(KERN_ERR, "Minor version number mismatch. "
+				"Expected [%d]; got [%d]\n",
+				ECRYPTFS_VERSION_MINOR, minor);
+		rc = -EINVAL;
+		goto out;
+	}
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_verify_auth_tok_from_key
+ * @auth_tok_key: key containing the authentication token
+ * @auth_tok: authentication token
+ *
+ * Returns zero on valid auth tok; -EINVAL if the payload is invalid; or
+ * -EKEYREVOKED if the key was revoked before we acquired its semaphore.
+ */
+static int
+ecryptfs_verify_auth_tok_from_key(struct key *auth_tok_key,
+				  struct ecryptfs_auth_tok **auth_tok)
+{
+	int rc = 0;
+
+	(*auth_tok) = ecryptfs_get_key_payload_data(auth_tok_key);
+	if (IS_ERR(*auth_tok)) {
+		rc = PTR_ERR(*auth_tok);
+		*auth_tok = NULL;
+		goto out;
+	}
+
+	if (ecryptfs_verify_version((*auth_tok)->version)) {
+		printk(KERN_ERR "Data structure version mismatch. Userspace "
+		       "tools must match eCryptfs kernel module with major "
+		       "version [%d] and minor version [%d]\n",
+		       ECRYPTFS_VERSION_MAJOR, ECRYPTFS_VERSION_MINOR);
+		rc = -EINVAL;
+		goto out;
+	}
+	if ((*auth_tok)->token_type != ECRYPTFS_PASSWORD
+	    && (*auth_tok)->token_type != ECRYPTFS_PRIVATE_KEY) {
+		printk(KERN_ERR "Invalid auth_tok structure "
+		       "returned from key query\n");
+		rc = -EINVAL;
+		goto out;
+	}
+out:
+	return rc;
+}
+
+static int
+ecryptfs_find_global_auth_tok_for_sig(
+	struct key **auth_tok_key,
+	struct ecryptfs_auth_tok **auth_tok,
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat, char *sig)
+{
+	struct ecryptfs_global_auth_tok *walker;
+	int rc = 0;
+
+	(*auth_tok_key) = NULL;
+	(*auth_tok) = NULL;
+	mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
+	list_for_each_entry(walker,
+			    &mount_crypt_stat->global_auth_tok_list,
+			    mount_crypt_stat_list) {
+		if (memcmp(walker->sig, sig, ECRYPTFS_SIG_SIZE_HEX))
+			continue;
+
+		if (walker->flags & ECRYPTFS_AUTH_TOK_INVALID) {
+			rc = -EINVAL;
+			goto out;
+		}
+
+		rc = key_validate(walker->global_auth_tok_key);
+		if (rc) {
+			if (rc == -EKEYEXPIRED)
+				goto out;
+			goto out_invalid_auth_tok;
+		}
+
+		down_write(&(walker->global_auth_tok_key->sem));
+		rc = ecryptfs_verify_auth_tok_from_key(
+				walker->global_auth_tok_key, auth_tok);
+		if (rc)
+			goto out_invalid_auth_tok_unlock;
+
+		(*auth_tok_key) = walker->global_auth_tok_key;
+		key_get(*auth_tok_key);
+		goto out;
+	}
+	rc = -ENOENT;
+	goto out;
+out_invalid_auth_tok_unlock:
+	up_write(&(walker->global_auth_tok_key->sem));
+out_invalid_auth_tok:
+	printk(KERN_WARNING "Invalidating auth tok with sig = [%s]\n", sig);
+	walker->flags |= ECRYPTFS_AUTH_TOK_INVALID;
+	key_put(walker->global_auth_tok_key);
+	walker->global_auth_tok_key = NULL;
+out:
+	mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
+	return rc;
+}
+
+/**
+ * ecryptfs_find_auth_tok_for_sig
+ * @auth_tok_key: key containing the authentication token
+ * @auth_tok: Set to the matching auth_tok; NULL if not found
+ * @mount_crypt_stat: inode crypt_stat crypto context
+ * @sig: Sig of auth_tok to find
+ *
+ * For now, this function simply looks at the registered auth_tok's
+ * linked off the mount_crypt_stat, so all the auth_toks that can be
+ * used must be registered at mount time. This function could
+ * potentially try a lot harder to find auth_tok's (e.g., by calling
+ * out to ecryptfsd to dynamically retrieve an auth_tok object) so
+ * that static registration of auth_tok's will no longer be necessary.
+ *
+ * Returns zero on no error; non-zero on error
+ */
+static int
+ecryptfs_find_auth_tok_for_sig(
+	struct key **auth_tok_key,
+	struct ecryptfs_auth_tok **auth_tok,
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
+	char *sig)
+{
+	int rc = 0;
+
+	rc = ecryptfs_find_global_auth_tok_for_sig(auth_tok_key, auth_tok,
+						   mount_crypt_stat, sig);
+	if (rc == -ENOENT) {
+		/* if the flag ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY is set in the
+		 * mount_crypt_stat structure, we prevent to use auth toks that
+		 * are not inserted through the ecryptfs_add_global_auth_tok
+		 * function.
+		 */
+		if (mount_crypt_stat->flags
+				& ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY)
+			return -EINVAL;
+
+		rc = ecryptfs_keyring_auth_tok_for_sig(auth_tok_key, auth_tok,
+						       sig);
+	}
+	return rc;
+}
+
+/*
+ * write_tag_70_packet can gobble a lot of stack space. We stuff most
+ * of the function's parameters in a kmalloc'd struct to help reduce
+ * eCryptfs' overall stack usage.
+ */
+struct ecryptfs_write_tag_70_packet_silly_stack {
+	u8 cipher_code;
+	size_t max_packet_size;
+	size_t packet_size_len;
+	size_t block_aligned_filename_size;
+	size_t block_size;
+	size_t i;
+	size_t j;
+	size_t num_rand_bytes;
+	struct mutex *tfm_mutex;
+	char *block_aligned_filename;
+	struct ecryptfs_auth_tok *auth_tok;
+	struct scatterlist src_sg[2];
+	struct scatterlist dst_sg[2];
+	struct crypto_skcipher *skcipher_tfm;
+	struct skcipher_request *skcipher_req;
+	char iv[ECRYPTFS_MAX_IV_BYTES];
+	char hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
+	char tmp_hash[ECRYPTFS_TAG_70_DIGEST_SIZE];
+	struct crypto_shash *hash_tfm;
+	struct shash_desc *hash_desc;
+};
+
+/*
+ * write_tag_70_packet - Write encrypted filename (EFN) packet against FNEK
+ * @filename: NULL-terminated filename string
+ *
+ * This is the simplest mechanism for achieving filename encryption in
+ * eCryptfs. It encrypts the given filename with the mount-wide
+ * filename encryption key (FNEK) and stores it in a packet to @dest,
+ * which the callee will encode and write directly into the dentry
+ * name.
+ */
+int
+ecryptfs_write_tag_70_packet(char *dest, size_t *remaining_bytes,
+			     size_t *packet_size,
+			     struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
+			     char *filename, size_t filename_size)
+{
+	struct ecryptfs_write_tag_70_packet_silly_stack *s;
+	struct key *auth_tok_key = NULL;
+	int rc = 0;
+
+	s = kzalloc(sizeof(*s), GFP_KERNEL);
+	if (!s)
+		return -ENOMEM;
+
+	(*packet_size) = 0;
+	rc = ecryptfs_find_auth_tok_for_sig(
+		&auth_tok_key,
+		&s->auth_tok, mount_crypt_stat,
+		mount_crypt_stat->global_default_fnek_sig);
+	if (rc) {
+		printk(KERN_ERR "%s: Error attempting to find auth tok for "
+		       "fnek sig [%s]; rc = [%d]\n", __func__,
+		       mount_crypt_stat->global_default_fnek_sig, rc);
+		goto out;
+	}
+	rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(
+		&s->skcipher_tfm,
+		&s->tfm_mutex, mount_crypt_stat->global_default_fn_cipher_name);
+	if (unlikely(rc)) {
+		printk(KERN_ERR "Internal error whilst attempting to get "
+		       "tfm and mutex for cipher name [%s]; rc = [%d]\n",
+		       mount_crypt_stat->global_default_fn_cipher_name, rc);
+		goto out;
+	}
+	mutex_lock(s->tfm_mutex);
+	s->block_size = crypto_skcipher_blocksize(s->skcipher_tfm);
+	/* Plus one for the \0 separator between the random prefix
+	 * and the plaintext filename */
+	s->num_rand_bytes = (ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES + 1);
+	s->block_aligned_filename_size = (s->num_rand_bytes + filename_size);
+	if ((s->block_aligned_filename_size % s->block_size) != 0) {
+		s->num_rand_bytes += (s->block_size
+				      - (s->block_aligned_filename_size
+					 % s->block_size));
+		s->block_aligned_filename_size = (s->num_rand_bytes
+						  + filename_size);
+	}
+	/* Octet 0: Tag 70 identifier
+	 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
+	 *              and block-aligned encrypted filename size)
+	 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
+	 * Octet N2-N3: Cipher identifier (1 octet)
+	 * Octets N3-N4: Block-aligned encrypted filename
+	 *  - Consists of a minimum number of random characters, a \0
+	 *    separator, and then the filename */
+	s->max_packet_size = (ECRYPTFS_TAG_70_MAX_METADATA_SIZE
+			      + s->block_aligned_filename_size);
+	if (!dest) {
+		(*packet_size) = s->max_packet_size;
+		goto out_unlock;
+	}
+	if (s->max_packet_size > (*remaining_bytes)) {
+		printk(KERN_WARNING "%s: Require [%zd] bytes to write; only "
+		       "[%zd] available\n", __func__, s->max_packet_size,
+		       (*remaining_bytes));
+		rc = -EINVAL;
+		goto out_unlock;
+	}
+
+	s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL);
+	if (!s->skcipher_req) {
+		printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
+		       "skcipher_request_alloc for %s\n", __func__,
+		       crypto_skcipher_driver_name(s->skcipher_tfm));
+		rc = -ENOMEM;
+		goto out_unlock;
+	}
+
+	skcipher_request_set_callback(s->skcipher_req,
+				      CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
+
+	s->block_aligned_filename = kzalloc(s->block_aligned_filename_size,
+					    GFP_KERNEL);
+	if (!s->block_aligned_filename) {
+		rc = -ENOMEM;
+		goto out_unlock;
+	}
+	dest[s->i++] = ECRYPTFS_TAG_70_PACKET_TYPE;
+	rc = ecryptfs_write_packet_length(&dest[s->i],
+					  (ECRYPTFS_SIG_SIZE
+					   + 1 /* Cipher code */
+					   + s->block_aligned_filename_size),
+					  &s->packet_size_len);
+	if (rc) {
+		printk(KERN_ERR "%s: Error generating tag 70 packet "
+		       "header; cannot generate packet length; rc = [%d]\n",
+		       __func__, rc);
+		goto out_free_unlock;
+	}
+	s->i += s->packet_size_len;
+	ecryptfs_from_hex(&dest[s->i],
+			  mount_crypt_stat->global_default_fnek_sig,
+			  ECRYPTFS_SIG_SIZE);
+	s->i += ECRYPTFS_SIG_SIZE;
+	s->cipher_code = ecryptfs_code_for_cipher_string(
+		mount_crypt_stat->global_default_fn_cipher_name,
+		mount_crypt_stat->global_default_fn_cipher_key_bytes);
+	if (s->cipher_code == 0) {
+		printk(KERN_WARNING "%s: Unable to generate code for "
+		       "cipher [%s] with key bytes [%zd]\n", __func__,
+		       mount_crypt_stat->global_default_fn_cipher_name,
+		       mount_crypt_stat->global_default_fn_cipher_key_bytes);
+		rc = -EINVAL;
+		goto out_free_unlock;
+	}
+	dest[s->i++] = s->cipher_code;
+	/* TODO: Support other key modules than passphrase for
+	 * filename encryption */
+	if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
+		rc = -EOPNOTSUPP;
+		printk(KERN_INFO "%s: Filename encryption only supports "
+		       "password tokens\n", __func__);
+		goto out_free_unlock;
+	}
+	s->hash_tfm = crypto_alloc_shash(ECRYPTFS_TAG_70_DIGEST, 0, 0);
+	if (IS_ERR(s->hash_tfm)) {
+			rc = PTR_ERR(s->hash_tfm);
+			printk(KERN_ERR "%s: Error attempting to "
+			       "allocate hash crypto context; rc = [%d]\n",
+			       __func__, rc);
+			goto out_free_unlock;
+	}
+
+	s->hash_desc = kmalloc(sizeof(*s->hash_desc) +
+			       crypto_shash_descsize(s->hash_tfm), GFP_KERNEL);
+	if (!s->hash_desc) {
+		rc = -ENOMEM;
+		goto out_release_free_unlock;
+	}
+
+	s->hash_desc->tfm = s->hash_tfm;
+
+	rc = crypto_shash_digest(s->hash_desc,
+				 (u8 *)s->auth_tok->token.password.session_key_encryption_key,
+				 s->auth_tok->token.password.session_key_encryption_key_bytes,
+				 s->hash);
+	if (rc) {
+		printk(KERN_ERR
+		       "%s: Error computing crypto hash; rc = [%d]\n",
+		       __func__, rc);
+		goto out_release_free_unlock;
+	}
+	for (s->j = 0; s->j < (s->num_rand_bytes - 1); s->j++) {
+		s->block_aligned_filename[s->j] =
+			s->hash[(s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)];
+		if ((s->j % ECRYPTFS_TAG_70_DIGEST_SIZE)
+		    == (ECRYPTFS_TAG_70_DIGEST_SIZE - 1)) {
+			rc = crypto_shash_digest(s->hash_desc, (u8 *)s->hash,
+						ECRYPTFS_TAG_70_DIGEST_SIZE,
+						s->tmp_hash);
+			if (rc) {
+				printk(KERN_ERR
+				       "%s: Error computing crypto hash; "
+				       "rc = [%d]\n", __func__, rc);
+				goto out_release_free_unlock;
+			}
+			memcpy(s->hash, s->tmp_hash,
+			       ECRYPTFS_TAG_70_DIGEST_SIZE);
+		}
+		if (s->block_aligned_filename[s->j] == '\0')
+			s->block_aligned_filename[s->j] = ECRYPTFS_NON_NULL;
+	}
+	memcpy(&s->block_aligned_filename[s->num_rand_bytes], filename,
+	       filename_size);
+	rc = virt_to_scatterlist(s->block_aligned_filename,
+				 s->block_aligned_filename_size, s->src_sg, 2);
+	if (rc < 1) {
+		printk(KERN_ERR "%s: Internal error whilst attempting to "
+		       "convert filename memory to scatterlist; rc = [%d]. "
+		       "block_aligned_filename_size = [%zd]\n", __func__, rc,
+		       s->block_aligned_filename_size);
+		goto out_release_free_unlock;
+	}
+	rc = virt_to_scatterlist(&dest[s->i], s->block_aligned_filename_size,
+				 s->dst_sg, 2);
+	if (rc < 1) {
+		printk(KERN_ERR "%s: Internal error whilst attempting to "
+		       "convert encrypted filename memory to scatterlist; "
+		       "rc = [%d]. block_aligned_filename_size = [%zd]\n",
+		       __func__, rc, s->block_aligned_filename_size);
+		goto out_release_free_unlock;
+	}
+	/* The characters in the first block effectively do the job
+	 * of the IV here, so we just use 0's for the IV. Note the
+	 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
+	 * >= ECRYPTFS_MAX_IV_BYTES. */
+	rc = crypto_skcipher_setkey(
+		s->skcipher_tfm,
+		s->auth_tok->token.password.session_key_encryption_key,
+		mount_crypt_stat->global_default_fn_cipher_key_bytes);
+	if (rc < 0) {
+		printk(KERN_ERR "%s: Error setting key for crypto context; "
+		       "rc = [%d]. s->auth_tok->token.password.session_key_"
+		       "encryption_key = [0x%p]; mount_crypt_stat->"
+		       "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
+		       rc,
+		       s->auth_tok->token.password.session_key_encryption_key,
+		       mount_crypt_stat->global_default_fn_cipher_key_bytes);
+		goto out_release_free_unlock;
+	}
+	skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg,
+				   s->block_aligned_filename_size, s->iv);
+	rc = crypto_skcipher_encrypt(s->skcipher_req);
+	if (rc) {
+		printk(KERN_ERR "%s: Error attempting to encrypt filename; "
+		       "rc = [%d]\n", __func__, rc);
+		goto out_release_free_unlock;
+	}
+	s->i += s->block_aligned_filename_size;
+	(*packet_size) = s->i;
+	(*remaining_bytes) -= (*packet_size);
+out_release_free_unlock:
+	crypto_free_shash(s->hash_tfm);
+out_free_unlock:
+	kfree_sensitive(s->block_aligned_filename);
+out_unlock:
+	mutex_unlock(s->tfm_mutex);
+out:
+	if (auth_tok_key) {
+		up_write(&(auth_tok_key->sem));
+		key_put(auth_tok_key);
+	}
+	skcipher_request_free(s->skcipher_req);
+	kfree_sensitive(s->hash_desc);
+	kfree(s);
+	return rc;
+}
+
+struct ecryptfs_parse_tag_70_packet_silly_stack {
+	u8 cipher_code;
+	size_t max_packet_size;
+	size_t packet_size_len;
+	size_t parsed_tag_70_packet_size;
+	size_t block_aligned_filename_size;
+	size_t block_size;
+	size_t i;
+	struct mutex *tfm_mutex;
+	char *decrypted_filename;
+	struct ecryptfs_auth_tok *auth_tok;
+	struct scatterlist src_sg[2];
+	struct scatterlist dst_sg[2];
+	struct crypto_skcipher *skcipher_tfm;
+	struct skcipher_request *skcipher_req;
+	char fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX + 1];
+	char iv[ECRYPTFS_MAX_IV_BYTES];
+	char cipher_string[ECRYPTFS_MAX_CIPHER_NAME_SIZE + 1];
+};
+
+/**
+ * ecryptfs_parse_tag_70_packet - Parse and process FNEK-encrypted passphrase packet
+ * @filename: This function kmalloc's the memory for the filename
+ * @filename_size: This function sets this to the amount of memory
+ *                 kmalloc'd for the filename
+ * @packet_size: This function sets this to the the number of octets
+ *               in the packet parsed
+ * @mount_crypt_stat: The mount-wide cryptographic context
+ * @data: The memory location containing the start of the tag 70
+ *        packet
+ * @max_packet_size: The maximum legal size of the packet to be parsed
+ *                   from @data
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int
+ecryptfs_parse_tag_70_packet(char **filename, size_t *filename_size,
+			     size_t *packet_size,
+			     struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
+			     char *data, size_t max_packet_size)
+{
+	struct ecryptfs_parse_tag_70_packet_silly_stack *s;
+	struct key *auth_tok_key = NULL;
+	int rc = 0;
+
+	(*packet_size) = 0;
+	(*filename_size) = 0;
+	(*filename) = NULL;
+	s = kzalloc(sizeof(*s), GFP_KERNEL);
+	if (!s)
+		return -ENOMEM;
+
+	if (max_packet_size < ECRYPTFS_TAG_70_MIN_METADATA_SIZE) {
+		printk(KERN_WARNING "%s: max_packet_size is [%zd]; it must be "
+		       "at least [%d]\n", __func__, max_packet_size,
+		       ECRYPTFS_TAG_70_MIN_METADATA_SIZE);
+		rc = -EINVAL;
+		goto out;
+	}
+	/* Octet 0: Tag 70 identifier
+	 * Octets 1-N1: Tag 70 packet size (includes cipher identifier
+	 *              and block-aligned encrypted filename size)
+	 * Octets N1-N2: FNEK sig (ECRYPTFS_SIG_SIZE)
+	 * Octet N2-N3: Cipher identifier (1 octet)
+	 * Octets N3-N4: Block-aligned encrypted filename
+	 *  - Consists of a minimum number of random numbers, a \0
+	 *    separator, and then the filename */
+	if (data[(*packet_size)++] != ECRYPTFS_TAG_70_PACKET_TYPE) {
+		printk(KERN_WARNING "%s: Invalid packet tag [0x%.2x]; must be "
+		       "tag [0x%.2x]\n", __func__,
+		       data[((*packet_size) - 1)], ECRYPTFS_TAG_70_PACKET_TYPE);
+		rc = -EINVAL;
+		goto out;
+	}
+	rc = ecryptfs_parse_packet_length(&data[(*packet_size)],
+					  &s->parsed_tag_70_packet_size,
+					  &s->packet_size_len);
+	if (rc) {
+		printk(KERN_WARNING "%s: Error parsing packet length; "
+		       "rc = [%d]\n", __func__, rc);
+		goto out;
+	}
+	s->block_aligned_filename_size = (s->parsed_tag_70_packet_size
+					  - ECRYPTFS_SIG_SIZE - 1);
+	if ((1 + s->packet_size_len + s->parsed_tag_70_packet_size)
+	    > max_packet_size) {
+		printk(KERN_WARNING "%s: max_packet_size is [%zd]; real packet "
+		       "size is [%zd]\n", __func__, max_packet_size,
+		       (1 + s->packet_size_len + 1
+			+ s->block_aligned_filename_size));
+		rc = -EINVAL;
+		goto out;
+	}
+	(*packet_size) += s->packet_size_len;
+	ecryptfs_to_hex(s->fnek_sig_hex, &data[(*packet_size)],
+			ECRYPTFS_SIG_SIZE);
+	s->fnek_sig_hex[ECRYPTFS_SIG_SIZE_HEX] = '\0';
+	(*packet_size) += ECRYPTFS_SIG_SIZE;
+	s->cipher_code = data[(*packet_size)++];
+	rc = ecryptfs_cipher_code_to_string(s->cipher_string, s->cipher_code);
+	if (rc) {
+		printk(KERN_WARNING "%s: Cipher code [%d] is invalid\n",
+		       __func__, s->cipher_code);
+		goto out;
+	}
+	rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
+					    &s->auth_tok, mount_crypt_stat,
+					    s->fnek_sig_hex);
+	if (rc) {
+		printk(KERN_ERR "%s: Error attempting to find auth tok for "
+		       "fnek sig [%s]; rc = [%d]\n", __func__, s->fnek_sig_hex,
+		       rc);
+		goto out;
+	}
+	rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&s->skcipher_tfm,
+							&s->tfm_mutex,
+							s->cipher_string);
+	if (unlikely(rc)) {
+		printk(KERN_ERR "Internal error whilst attempting to get "
+		       "tfm and mutex for cipher name [%s]; rc = [%d]\n",
+		       s->cipher_string, rc);
+		goto out;
+	}
+	mutex_lock(s->tfm_mutex);
+	rc = virt_to_scatterlist(&data[(*packet_size)],
+				 s->block_aligned_filename_size, s->src_sg, 2);
+	if (rc < 1) {
+		printk(KERN_ERR "%s: Internal error whilst attempting to "
+		       "convert encrypted filename memory to scatterlist; "
+		       "rc = [%d]. block_aligned_filename_size = [%zd]\n",
+		       __func__, rc, s->block_aligned_filename_size);
+		goto out_unlock;
+	}
+	(*packet_size) += s->block_aligned_filename_size;
+	s->decrypted_filename = kmalloc(s->block_aligned_filename_size,
+					GFP_KERNEL);
+	if (!s->decrypted_filename) {
+		rc = -ENOMEM;
+		goto out_unlock;
+	}
+	rc = virt_to_scatterlist(s->decrypted_filename,
+				 s->block_aligned_filename_size, s->dst_sg, 2);
+	if (rc < 1) {
+		printk(KERN_ERR "%s: Internal error whilst attempting to "
+		       "convert decrypted filename memory to scatterlist; "
+		       "rc = [%d]. block_aligned_filename_size = [%zd]\n",
+		       __func__, rc, s->block_aligned_filename_size);
+		goto out_free_unlock;
+	}
+
+	s->skcipher_req = skcipher_request_alloc(s->skcipher_tfm, GFP_KERNEL);
+	if (!s->skcipher_req) {
+		printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
+		       "skcipher_request_alloc for %s\n", __func__,
+		       crypto_skcipher_driver_name(s->skcipher_tfm));
+		rc = -ENOMEM;
+		goto out_free_unlock;
+	}
+
+	skcipher_request_set_callback(s->skcipher_req,
+				      CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
+
+	/* The characters in the first block effectively do the job of
+	 * the IV here, so we just use 0's for the IV. Note the
+	 * constraint that ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES
+	 * >= ECRYPTFS_MAX_IV_BYTES. */
+	/* TODO: Support other key modules than passphrase for
+	 * filename encryption */
+	if (s->auth_tok->token_type != ECRYPTFS_PASSWORD) {
+		rc = -EOPNOTSUPP;
+		printk(KERN_INFO "%s: Filename encryption only supports "
+		       "password tokens\n", __func__);
+		goto out_free_unlock;
+	}
+	rc = crypto_skcipher_setkey(
+		s->skcipher_tfm,
+		s->auth_tok->token.password.session_key_encryption_key,
+		mount_crypt_stat->global_default_fn_cipher_key_bytes);
+	if (rc < 0) {
+		printk(KERN_ERR "%s: Error setting key for crypto context; "
+		       "rc = [%d]. s->auth_tok->token.password.session_key_"
+		       "encryption_key = [0x%p]; mount_crypt_stat->"
+		       "global_default_fn_cipher_key_bytes = [%zd]\n", __func__,
+		       rc,
+		       s->auth_tok->token.password.session_key_encryption_key,
+		       mount_crypt_stat->global_default_fn_cipher_key_bytes);
+		goto out_free_unlock;
+	}
+	skcipher_request_set_crypt(s->skcipher_req, s->src_sg, s->dst_sg,
+				   s->block_aligned_filename_size, s->iv);
+	rc = crypto_skcipher_decrypt(s->skcipher_req);
+	if (rc) {
+		printk(KERN_ERR "%s: Error attempting to decrypt filename; "
+		       "rc = [%d]\n", __func__, rc);
+		goto out_free_unlock;
+	}
+
+	while (s->i < s->block_aligned_filename_size &&
+	       s->decrypted_filename[s->i] != '\0')
+		s->i++;
+	if (s->i == s->block_aligned_filename_size) {
+		printk(KERN_WARNING "%s: Invalid tag 70 packet; could not "
+		       "find valid separator between random characters and "
+		       "the filename\n", __func__);
+		rc = -EINVAL;
+		goto out_free_unlock;
+	}
+	s->i++;
+	(*filename_size) = (s->block_aligned_filename_size - s->i);
+	if (!((*filename_size) > 0 && (*filename_size < PATH_MAX))) {
+		printk(KERN_WARNING "%s: Filename size is [%zd], which is "
+		       "invalid\n", __func__, (*filename_size));
+		rc = -EINVAL;
+		goto out_free_unlock;
+	}
+	(*filename) = kmalloc(((*filename_size) + 1), GFP_KERNEL);
+	if (!(*filename)) {
+		rc = -ENOMEM;
+		goto out_free_unlock;
+	}
+	memcpy((*filename), &s->decrypted_filename[s->i], (*filename_size));
+	(*filename)[(*filename_size)] = '\0';
+out_free_unlock:
+	kfree(s->decrypted_filename);
+out_unlock:
+	mutex_unlock(s->tfm_mutex);
+out:
+	if (rc) {
+		(*packet_size) = 0;
+		(*filename_size) = 0;
+		(*filename) = NULL;
+	}
+	if (auth_tok_key) {
+		up_write(&(auth_tok_key->sem));
+		key_put(auth_tok_key);
+	}
+	skcipher_request_free(s->skcipher_req);
+	kfree(s);
+	return rc;
+}
+
+static int
+ecryptfs_get_auth_tok_sig(char **sig, struct ecryptfs_auth_tok *auth_tok)
+{
+	int rc = 0;
+
+	(*sig) = NULL;
+	switch (auth_tok->token_type) {
+	case ECRYPTFS_PASSWORD:
+		(*sig) = auth_tok->token.password.signature;
+		break;
+	case ECRYPTFS_PRIVATE_KEY:
+		(*sig) = auth_tok->token.private_key.signature;
+		break;
+	default:
+		printk(KERN_ERR "Cannot get sig for auth_tok of type [%d]\n",
+		       auth_tok->token_type);
+		rc = -EINVAL;
+	}
+	return rc;
+}
+
+/**
+ * decrypt_pki_encrypted_session_key - Decrypt the session key with the given auth_tok.
+ * @auth_tok: The key authentication token used to decrypt the session key
+ * @crypt_stat: The cryptographic context
+ *
+ * Returns zero on success; non-zero error otherwise.
+ */
+static int
+decrypt_pki_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
+				  struct ecryptfs_crypt_stat *crypt_stat)
+{
+	u8 cipher_code = 0;
+	struct ecryptfs_msg_ctx *msg_ctx;
+	struct ecryptfs_message *msg = NULL;
+	char *auth_tok_sig;
+	char *payload = NULL;
+	size_t payload_len = 0;
+	int rc;
+
+	rc = ecryptfs_get_auth_tok_sig(&auth_tok_sig, auth_tok);
+	if (rc) {
+		printk(KERN_ERR "Unrecognized auth tok type: [%d]\n",
+		       auth_tok->token_type);
+		goto out;
+	}
+	rc = write_tag_64_packet(auth_tok_sig, &(auth_tok->session_key),
+				 &payload, &payload_len);
+	if (rc) {
+		ecryptfs_printk(KERN_ERR, "Failed to write tag 64 packet\n");
+		goto out;
+	}
+	rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
+	if (rc) {
+		ecryptfs_printk(KERN_ERR, "Error sending message to "
+				"ecryptfsd: %d\n", rc);
+		goto out;
+	}
+	rc = ecryptfs_wait_for_response(msg_ctx, &msg);
+	if (rc) {
+		ecryptfs_printk(KERN_ERR, "Failed to receive tag 65 packet "
+				"from the user space daemon\n");
+		rc = -EIO;
+		goto out;
+	}
+	rc = parse_tag_65_packet(&(auth_tok->session_key),
+				 &cipher_code, msg);
+	if (rc) {
+		printk(KERN_ERR "Failed to parse tag 65 packet; rc = [%d]\n",
+		       rc);
+		goto out;
+	}
+	auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
+	memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
+	       auth_tok->session_key.decrypted_key_size);
+	crypt_stat->key_size = auth_tok->session_key.decrypted_key_size;
+	rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher, cipher_code);
+	if (rc) {
+		ecryptfs_printk(KERN_ERR, "Cipher code [%d] is invalid\n",
+				cipher_code);
+		goto out;
+	}
+	crypt_stat->flags |= ECRYPTFS_KEY_VALID;
+	if (ecryptfs_verbosity > 0) {
+		ecryptfs_printk(KERN_DEBUG, "Decrypted session key:\n");
+		ecryptfs_dump_hex(crypt_stat->key,
+				  crypt_stat->key_size);
+	}
+out:
+	kfree(msg);
+	kfree(payload);
+	return rc;
+}
+
+static void wipe_auth_tok_list(struct list_head *auth_tok_list_head)
+{
+	struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
+	struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
+
+	list_for_each_entry_safe(auth_tok_list_item, auth_tok_list_item_tmp,
+				 auth_tok_list_head, list) {
+		list_del(&auth_tok_list_item->list);
+		kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
+				auth_tok_list_item);
+	}
+}
+
+struct kmem_cache *ecryptfs_auth_tok_list_item_cache;
+
+/**
+ * parse_tag_1_packet
+ * @crypt_stat: The cryptographic context to modify based on packet contents
+ * @data: The raw bytes of the packet.
+ * @auth_tok_list: eCryptfs parses packets into authentication tokens;
+ *                 a new authentication token will be placed at the
+ *                 end of this list for this packet.
+ * @new_auth_tok: Pointer to a pointer to memory that this function
+ *                allocates; sets the memory address of the pointer to
+ *                NULL on error. This object is added to the
+ *                auth_tok_list.
+ * @packet_size: This function writes the size of the parsed packet
+ *               into this memory location; zero on error.
+ * @max_packet_size: The maximum allowable packet size
+ *
+ * Returns zero on success; non-zero on error.
+ */
+static int
+parse_tag_1_packet(struct ecryptfs_crypt_stat *crypt_stat,
+		   unsigned char *data, struct list_head *auth_tok_list,
+		   struct ecryptfs_auth_tok **new_auth_tok,
+		   size_t *packet_size, size_t max_packet_size)
+{
+	size_t body_size;
+	struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
+	size_t length_size;
+	int rc = 0;
+
+	(*packet_size) = 0;
+	(*new_auth_tok) = NULL;
+	/**
+	 * This format is inspired by OpenPGP; see RFC 2440
+	 * packet tag 1
+	 *
+	 * Tag 1 identifier (1 byte)
+	 * Max Tag 1 packet size (max 3 bytes)
+	 * Version (1 byte)
+	 * Key identifier (8 bytes; ECRYPTFS_SIG_SIZE)
+	 * Cipher identifier (1 byte)
+	 * Encrypted key size (arbitrary)
+	 *
+	 * 12 bytes minimum packet size
+	 */
+	if (unlikely(max_packet_size < 12)) {
+		printk(KERN_ERR "Invalid max packet size; must be >=12\n");
+		rc = -EINVAL;
+		goto out;
+	}
+	if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
+		printk(KERN_ERR "Enter w/ first byte != 0x%.2x\n",
+		       ECRYPTFS_TAG_1_PACKET_TYPE);
+		rc = -EINVAL;
+		goto out;
+	}
+	/* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
+	 * at end of function upon failure */
+	auth_tok_list_item =
+		kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache,
+				  GFP_KERNEL);
+	if (!auth_tok_list_item) {
+		printk(KERN_ERR "Unable to allocate memory\n");
+		rc = -ENOMEM;
+		goto out;
+	}
+	(*new_auth_tok) = &auth_tok_list_item->auth_tok;
+	rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
+					  &length_size);
+	if (rc) {
+		printk(KERN_WARNING "Error parsing packet length; "
+		       "rc = [%d]\n", rc);
+		goto out_free;
+	}
+	if (unlikely(body_size < (ECRYPTFS_SIG_SIZE + 2))) {
+		printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
+		rc = -EINVAL;
+		goto out_free;
+	}
+	(*packet_size) += length_size;
+	if (unlikely((*packet_size) + body_size > max_packet_size)) {
+		printk(KERN_WARNING "Packet size exceeds max\n");
+		rc = -EINVAL;
+		goto out_free;
+	}
+	if (unlikely(data[(*packet_size)++] != 0x03)) {
+		printk(KERN_WARNING "Unknown version number [%d]\n",
+		       data[(*packet_size) - 1]);
+		rc = -EINVAL;
+		goto out_free;
+	}
+	ecryptfs_to_hex((*new_auth_tok)->token.private_key.signature,
+			&data[(*packet_size)], ECRYPTFS_SIG_SIZE);
+	*packet_size += ECRYPTFS_SIG_SIZE;
+	/* This byte is skipped because the kernel does not need to
+	 * know which public key encryption algorithm was used */
+	(*packet_size)++;
+	(*new_auth_tok)->session_key.encrypted_key_size =
+		body_size - (ECRYPTFS_SIG_SIZE + 2);
+	if ((*new_auth_tok)->session_key.encrypted_key_size
+	    > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
+		printk(KERN_WARNING "Tag 1 packet contains key larger "
+		       "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
+		rc = -EINVAL;
+		goto out_free;
+	}
+	memcpy((*new_auth_tok)->session_key.encrypted_key,
+	       &data[(*packet_size)], (body_size - (ECRYPTFS_SIG_SIZE + 2)));
+	(*packet_size) += (*new_auth_tok)->session_key.encrypted_key_size;
+	(*new_auth_tok)->session_key.flags &=
+		~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
+	(*new_auth_tok)->session_key.flags |=
+		ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
+	(*new_auth_tok)->token_type = ECRYPTFS_PRIVATE_KEY;
+	(*new_auth_tok)->flags = 0;
+	(*new_auth_tok)->session_key.flags &=
+		~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
+	(*new_auth_tok)->session_key.flags &=
+		~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
+	list_add(&auth_tok_list_item->list, auth_tok_list);
+	goto out;
+out_free:
+	(*new_auth_tok) = NULL;
+	memset(auth_tok_list_item, 0,
+	       sizeof(struct ecryptfs_auth_tok_list_item));
+	kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
+			auth_tok_list_item);
+out:
+	if (rc)
+		(*packet_size) = 0;
+	return rc;
+}
+
+/**
+ * parse_tag_3_packet
+ * @crypt_stat: The cryptographic context to modify based on packet
+ *              contents.
+ * @data: The raw bytes of the packet.
+ * @auth_tok_list: eCryptfs parses packets into authentication tokens;
+ *                 a new authentication token will be placed at the end
+ *                 of this list for this packet.
+ * @new_auth_tok: Pointer to a pointer to memory that this function
+ *                allocates; sets the memory address of the pointer to
+ *                NULL on error. This object is added to the
+ *                auth_tok_list.
+ * @packet_size: This function writes the size of the parsed packet
+ *               into this memory location; zero on error.
+ * @max_packet_size: maximum number of bytes to parse
+ *
+ * Returns zero on success; non-zero on error.
+ */
+static int
+parse_tag_3_packet(struct ecryptfs_crypt_stat *crypt_stat,
+		   unsigned char *data, struct list_head *auth_tok_list,
+		   struct ecryptfs_auth_tok **new_auth_tok,
+		   size_t *packet_size, size_t max_packet_size)
+{
+	size_t body_size;
+	struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
+	size_t length_size;
+	int rc = 0;
+
+	(*packet_size) = 0;
+	(*new_auth_tok) = NULL;
+	/**
+	 *This format is inspired by OpenPGP; see RFC 2440
+	 * packet tag 3
+	 *
+	 * Tag 3 identifier (1 byte)
+	 * Max Tag 3 packet size (max 3 bytes)
+	 * Version (1 byte)
+	 * Cipher code (1 byte)
+	 * S2K specifier (1 byte)
+	 * Hash identifier (1 byte)
+	 * Salt (ECRYPTFS_SALT_SIZE)
+	 * Hash iterations (1 byte)
+	 * Encrypted key (arbitrary)
+	 *
+	 * (ECRYPTFS_SALT_SIZE + 7) minimum packet size
+	 */
+	if (max_packet_size < (ECRYPTFS_SALT_SIZE + 7)) {
+		printk(KERN_ERR "Max packet size too large\n");
+		rc = -EINVAL;
+		goto out;
+	}
+	if (data[(*packet_size)++] != ECRYPTFS_TAG_3_PACKET_TYPE) {
+		printk(KERN_ERR "First byte != 0x%.2x; invalid packet\n",
+		       ECRYPTFS_TAG_3_PACKET_TYPE);
+		rc = -EINVAL;
+		goto out;
+	}
+	/* Released: wipe_auth_tok_list called in ecryptfs_parse_packet_set or
+	 * at end of function upon failure */
+	auth_tok_list_item =
+	    kmem_cache_zalloc(ecryptfs_auth_tok_list_item_cache, GFP_KERNEL);
+	if (!auth_tok_list_item) {
+		printk(KERN_ERR "Unable to allocate memory\n");
+		rc = -ENOMEM;
+		goto out;
+	}
+	(*new_auth_tok) = &auth_tok_list_item->auth_tok;
+	rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
+					  &length_size);
+	if (rc) {
+		printk(KERN_WARNING "Error parsing packet length; rc = [%d]\n",
+		       rc);
+		goto out_free;
+	}
+	if (unlikely(body_size < (ECRYPTFS_SALT_SIZE + 5))) {
+		printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
+		rc = -EINVAL;
+		goto out_free;
+	}
+	(*packet_size) += length_size;
+	if (unlikely((*packet_size) + body_size > max_packet_size)) {
+		printk(KERN_ERR "Packet size exceeds max\n");
+		rc = -EINVAL;
+		goto out_free;
+	}
+	(*new_auth_tok)->session_key.encrypted_key_size =
+		(body_size - (ECRYPTFS_SALT_SIZE + 5));
+	if ((*new_auth_tok)->session_key.encrypted_key_size
+	    > ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) {
+		printk(KERN_WARNING "Tag 3 packet contains key larger "
+		       "than ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES\n");
+		rc = -EINVAL;
+		goto out_free;
+	}
+	if (unlikely(data[(*packet_size)++] != 0x04)) {
+		printk(KERN_WARNING "Unknown version number [%d]\n",
+		       data[(*packet_size) - 1]);
+		rc = -EINVAL;
+		goto out_free;
+	}
+	rc = ecryptfs_cipher_code_to_string(crypt_stat->cipher,
+					    (u16)data[(*packet_size)]);
+	if (rc)
+		goto out_free;
+	/* A little extra work to differentiate among the AES key
+	 * sizes; see RFC2440 */
+	switch(data[(*packet_size)++]) {
+	case RFC2440_CIPHER_AES_192:
+		crypt_stat->key_size = 24;
+		break;
+	default:
+		crypt_stat->key_size =
+			(*new_auth_tok)->session_key.encrypted_key_size;
+	}
+	rc = ecryptfs_init_crypt_ctx(crypt_stat);
+	if (rc)
+		goto out_free;
+	if (unlikely(data[(*packet_size)++] != 0x03)) {
+		printk(KERN_WARNING "Only S2K ID 3 is currently supported\n");
+		rc = -ENOSYS;
+		goto out_free;
+	}
+	/* TODO: finish the hash mapping */
+	switch (data[(*packet_size)++]) {
+	case 0x01: /* See RFC2440 for these numbers and their mappings */
+		/* Choose MD5 */
+		memcpy((*new_auth_tok)->token.password.salt,
+		       &data[(*packet_size)], ECRYPTFS_SALT_SIZE);
+		(*packet_size) += ECRYPTFS_SALT_SIZE;
+		/* This conversion was taken straight from RFC2440 */
+		(*new_auth_tok)->token.password.hash_iterations =
+			((u32) 16 + (data[(*packet_size)] & 15))
+				<< ((data[(*packet_size)] >> 4) + 6);
+		(*packet_size)++;
+		/* Friendly reminder:
+		 * (*new_auth_tok)->session_key.encrypted_key_size =
+		 *         (body_size - (ECRYPTFS_SALT_SIZE + 5)); */
+		memcpy((*new_auth_tok)->session_key.encrypted_key,
+		       &data[(*packet_size)],
+		       (*new_auth_tok)->session_key.encrypted_key_size);
+		(*packet_size) +=
+			(*new_auth_tok)->session_key.encrypted_key_size;
+		(*new_auth_tok)->session_key.flags &=
+			~ECRYPTFS_CONTAINS_DECRYPTED_KEY;
+		(*new_auth_tok)->session_key.flags |=
+			ECRYPTFS_CONTAINS_ENCRYPTED_KEY;
+		(*new_auth_tok)->token.password.hash_algo = 0x01; /* MD5 */
+		break;
+	default:
+		ecryptfs_printk(KERN_ERR, "Unsupported hash algorithm: "
+				"[%d]\n", data[(*packet_size) - 1]);
+		rc = -ENOSYS;
+		goto out_free;
+	}
+	(*new_auth_tok)->token_type = ECRYPTFS_PASSWORD;
+	/* TODO: Parametarize; we might actually want userspace to
+	 * decrypt the session key. */
+	(*new_auth_tok)->session_key.flags &=
+			    ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_DECRYPT);
+	(*new_auth_tok)->session_key.flags &=
+			    ~(ECRYPTFS_USERSPACE_SHOULD_TRY_TO_ENCRYPT);
+	list_add(&auth_tok_list_item->list, auth_tok_list);
+	goto out;
+out_free:
+	(*new_auth_tok) = NULL;
+	memset(auth_tok_list_item, 0,
+	       sizeof(struct ecryptfs_auth_tok_list_item));
+	kmem_cache_free(ecryptfs_auth_tok_list_item_cache,
+			auth_tok_list_item);
+out:
+	if (rc)
+		(*packet_size) = 0;
+	return rc;
+}
+
+/**
+ * parse_tag_11_packet
+ * @data: The raw bytes of the packet
+ * @contents: This function writes the data contents of the literal
+ *            packet into this memory location
+ * @max_contents_bytes: The maximum number of bytes that this function
+ *                      is allowed to write into contents
+ * @tag_11_contents_size: This function writes the size of the parsed
+ *                        contents into this memory location; zero on
+ *                        error
+ * @packet_size: This function writes the size of the parsed packet
+ *               into this memory location; zero on error
+ * @max_packet_size: maximum number of bytes to parse
+ *
+ * Returns zero on success; non-zero on error.
+ */
+static int
+parse_tag_11_packet(unsigned char *data, unsigned char *contents,
+		    size_t max_contents_bytes, size_t *tag_11_contents_size,
+		    size_t *packet_size, size_t max_packet_size)
+{
+	size_t body_size;
+	size_t length_size;
+	int rc = 0;
+
+	(*packet_size) = 0;
+	(*tag_11_contents_size) = 0;
+	/* This format is inspired by OpenPGP; see RFC 2440
+	 * packet tag 11
+	 *
+	 * Tag 11 identifier (1 byte)
+	 * Max Tag 11 packet size (max 3 bytes)
+	 * Binary format specifier (1 byte)
+	 * Filename length (1 byte)
+	 * Filename ("_CONSOLE") (8 bytes)
+	 * Modification date (4 bytes)
+	 * Literal data (arbitrary)
+	 *
+	 * We need at least 16 bytes of data for the packet to even be
+	 * valid.
+	 */
+	if (max_packet_size < 16) {
+		printk(KERN_ERR "Maximum packet size too small\n");
+		rc = -EINVAL;
+		goto out;
+	}
+	if (data[(*packet_size)++] != ECRYPTFS_TAG_11_PACKET_TYPE) {
+		printk(KERN_WARNING "Invalid tag 11 packet format\n");
+		rc = -EINVAL;
+		goto out;
+	}
+	rc = ecryptfs_parse_packet_length(&data[(*packet_size)], &body_size,
+					  &length_size);
+	if (rc) {
+		printk(KERN_WARNING "Invalid tag 11 packet format\n");
+		goto out;
+	}
+	if (body_size < 14) {
+		printk(KERN_WARNING "Invalid body size ([%td])\n", body_size);
+		rc = -EINVAL;
+		goto out;
+	}
+	(*packet_size) += length_size;
+	(*tag_11_contents_size) = (body_size - 14);
+	if (unlikely((*packet_size) + body_size + 1 > max_packet_size)) {
+		printk(KERN_ERR "Packet size exceeds max\n");
+		rc = -EINVAL;
+		goto out;
+	}
+	if (unlikely((*tag_11_contents_size) > max_contents_bytes)) {
+		printk(KERN_ERR "Literal data section in tag 11 packet exceeds "
+		       "expected size\n");
+		rc = -EINVAL;
+		goto out;
+	}
+	if (data[(*packet_size)++] != 0x62) {
+		printk(KERN_WARNING "Unrecognizable packet\n");
+		rc = -EINVAL;
+		goto out;
+	}
+	if (data[(*packet_size)++] != 0x08) {
+		printk(KERN_WARNING "Unrecognizable packet\n");
+		rc = -EINVAL;
+		goto out;
+	}
+	(*packet_size) += 12; /* Ignore filename and modification date */
+	memcpy(contents, &data[(*packet_size)], (*tag_11_contents_size));
+	(*packet_size) += (*tag_11_contents_size);
+out:
+	if (rc) {
+		(*packet_size) = 0;
+		(*tag_11_contents_size) = 0;
+	}
+	return rc;
+}
+
+int ecryptfs_keyring_auth_tok_for_sig(struct key **auth_tok_key,
+				      struct ecryptfs_auth_tok **auth_tok,
+				      char *sig)
+{
+	int rc = 0;
+
+	(*auth_tok_key) = request_key(&key_type_user, sig, NULL);
+	if (IS_ERR(*auth_tok_key)) {
+		(*auth_tok_key) = ecryptfs_get_encrypted_key(sig);
+		if (IS_ERR(*auth_tok_key)) {
+			printk(KERN_ERR "Could not find key with description: [%s]\n",
+			      sig);
+			rc = process_request_key_err(PTR_ERR(*auth_tok_key));
+			(*auth_tok_key) = NULL;
+			goto out;
+		}
+	}
+	down_write(&(*auth_tok_key)->sem);
+	rc = ecryptfs_verify_auth_tok_from_key(*auth_tok_key, auth_tok);
+	if (rc) {
+		up_write(&(*auth_tok_key)->sem);
+		key_put(*auth_tok_key);
+		(*auth_tok_key) = NULL;
+		goto out;
+	}
+out:
+	return rc;
+}
+
+/**
+ * decrypt_passphrase_encrypted_session_key - Decrypt the session key with the given auth_tok.
+ * @auth_tok: The passphrase authentication token to use to encrypt the FEK
+ * @crypt_stat: The cryptographic context
+ *
+ * Returns zero on success; non-zero error otherwise
+ */
+static int
+decrypt_passphrase_encrypted_session_key(struct ecryptfs_auth_tok *auth_tok,
+					 struct ecryptfs_crypt_stat *crypt_stat)
+{
+	struct scatterlist dst_sg[2];
+	struct scatterlist src_sg[2];
+	struct mutex *tfm_mutex;
+	struct crypto_skcipher *tfm;
+	struct skcipher_request *req = NULL;
+	int rc = 0;
+
+	if (unlikely(ecryptfs_verbosity > 0)) {
+		ecryptfs_printk(
+			KERN_DEBUG, "Session key encryption key (size [%d]):\n",
+			auth_tok->token.password.session_key_encryption_key_bytes);
+		ecryptfs_dump_hex(
+			auth_tok->token.password.session_key_encryption_key,
+			auth_tok->token.password.session_key_encryption_key_bytes);
+	}
+	rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
+							crypt_stat->cipher);
+	if (unlikely(rc)) {
+		printk(KERN_ERR "Internal error whilst attempting to get "
+		       "tfm and mutex for cipher name [%s]; rc = [%d]\n",
+		       crypt_stat->cipher, rc);
+		goto out;
+	}
+	rc = virt_to_scatterlist(auth_tok->session_key.encrypted_key,
+				 auth_tok->session_key.encrypted_key_size,
+				 src_sg, 2);
+	if (rc < 1 || rc > 2) {
+		printk(KERN_ERR "Internal error whilst attempting to convert "
+			"auth_tok->session_key.encrypted_key to scatterlist; "
+			"expected rc = 1; got rc = [%d]. "
+		       "auth_tok->session_key.encrypted_key_size = [%d]\n", rc,
+			auth_tok->session_key.encrypted_key_size);
+		goto out;
+	}
+	auth_tok->session_key.decrypted_key_size =
+		auth_tok->session_key.encrypted_key_size;
+	rc = virt_to_scatterlist(auth_tok->session_key.decrypted_key,
+				 auth_tok->session_key.decrypted_key_size,
+				 dst_sg, 2);
+	if (rc < 1 || rc > 2) {
+		printk(KERN_ERR "Internal error whilst attempting to convert "
+			"auth_tok->session_key.decrypted_key to scatterlist; "
+			"expected rc = 1; got rc = [%d]\n", rc);
+		goto out;
+	}
+	mutex_lock(tfm_mutex);
+	req = skcipher_request_alloc(tfm, GFP_KERNEL);
+	if (!req) {
+		mutex_unlock(tfm_mutex);
+		printk(KERN_ERR "%s: Out of kernel memory whilst attempting to "
+		       "skcipher_request_alloc for %s\n", __func__,
+		       crypto_skcipher_driver_name(tfm));
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
+				      NULL, NULL);
+	rc = crypto_skcipher_setkey(
+		tfm, auth_tok->token.password.session_key_encryption_key,
+		crypt_stat->key_size);
+	if (unlikely(rc < 0)) {
+		mutex_unlock(tfm_mutex);
+		printk(KERN_ERR "Error setting key for crypto context\n");
+		rc = -EINVAL;
+		goto out;
+	}
+	skcipher_request_set_crypt(req, src_sg, dst_sg,
+				   auth_tok->session_key.encrypted_key_size,
+				   NULL);
+	rc = crypto_skcipher_decrypt(req);
+	mutex_unlock(tfm_mutex);
+	if (unlikely(rc)) {
+		printk(KERN_ERR "Error decrypting; rc = [%d]\n", rc);
+		goto out;
+	}
+	auth_tok->session_key.flags |= ECRYPTFS_CONTAINS_DECRYPTED_KEY;
+	memcpy(crypt_stat->key, auth_tok->session_key.decrypted_key,
+	       auth_tok->session_key.decrypted_key_size);
+	crypt_stat->flags |= ECRYPTFS_KEY_VALID;
+	if (unlikely(ecryptfs_verbosity > 0)) {
+		ecryptfs_printk(KERN_DEBUG, "FEK of size [%zd]:\n",
+				crypt_stat->key_size);
+		ecryptfs_dump_hex(crypt_stat->key,
+				  crypt_stat->key_size);
+	}
+out:
+	skcipher_request_free(req);
+	return rc;
+}
+
+/**
+ * ecryptfs_parse_packet_set
+ * @crypt_stat: The cryptographic context
+ * @src: Virtual address of region of memory containing the packets
+ * @ecryptfs_dentry: The eCryptfs dentry associated with the packet set
+ *
+ * Get crypt_stat to have the file's session key if the requisite key
+ * is available to decrypt the session key.
+ *
+ * Returns Zero if a valid authentication token was retrieved and
+ * processed; negative value for file not encrypted or for error
+ * conditions.
+ */
+int ecryptfs_parse_packet_set(struct ecryptfs_crypt_stat *crypt_stat,
+			      unsigned char *src,
+			      struct dentry *ecryptfs_dentry)
+{
+	size_t i = 0;
+	size_t found_auth_tok;
+	size_t next_packet_is_auth_tok_packet;
+	struct list_head auth_tok_list;
+	struct ecryptfs_auth_tok *matching_auth_tok;
+	struct ecryptfs_auth_tok *candidate_auth_tok;
+	char *candidate_auth_tok_sig;
+	size_t packet_size;
+	struct ecryptfs_auth_tok *new_auth_tok;
+	unsigned char sig_tmp_space[ECRYPTFS_SIG_SIZE];
+	struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
+	size_t tag_11_contents_size;
+	size_t tag_11_packet_size;
+	struct key *auth_tok_key = NULL;
+	int rc = 0;
+
+	INIT_LIST_HEAD(&auth_tok_list);
+	/* Parse the header to find as many packets as we can; these will be
+	 * added the our &auth_tok_list */
+	next_packet_is_auth_tok_packet = 1;
+	while (next_packet_is_auth_tok_packet) {
+		size_t max_packet_size = ((PAGE_SIZE - 8) - i);
+
+		switch (src[i]) {
+		case ECRYPTFS_TAG_3_PACKET_TYPE:
+			rc = parse_tag_3_packet(crypt_stat,
+						(unsigned char *)&src[i],
+						&auth_tok_list, &new_auth_tok,
+						&packet_size, max_packet_size);
+			if (rc) {
+				ecryptfs_printk(KERN_ERR, "Error parsing "
+						"tag 3 packet\n");
+				rc = -EIO;
+				goto out_wipe_list;
+			}
+			i += packet_size;
+			rc = parse_tag_11_packet((unsigned char *)&src[i],
+						 sig_tmp_space,
+						 ECRYPTFS_SIG_SIZE,
+						 &tag_11_contents_size,
+						 &tag_11_packet_size,
+						 max_packet_size);
+			if (rc) {
+				ecryptfs_printk(KERN_ERR, "No valid "
+						"(ecryptfs-specific) literal "
+						"packet containing "
+						"authentication token "
+						"signature found after "
+						"tag 3 packet\n");
+				rc = -EIO;
+				goto out_wipe_list;
+			}
+			i += tag_11_packet_size;
+			if (ECRYPTFS_SIG_SIZE != tag_11_contents_size) {
+				ecryptfs_printk(KERN_ERR, "Expected "
+						"signature of size [%d]; "
+						"read size [%zd]\n",
+						ECRYPTFS_SIG_SIZE,
+						tag_11_contents_size);
+				rc = -EIO;
+				goto out_wipe_list;
+			}
+			ecryptfs_to_hex(new_auth_tok->token.password.signature,
+					sig_tmp_space, tag_11_contents_size);
+			new_auth_tok->token.password.signature[
+				ECRYPTFS_PASSWORD_SIG_SIZE] = '\0';
+			crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
+			break;
+		case ECRYPTFS_TAG_1_PACKET_TYPE:
+			rc = parse_tag_1_packet(crypt_stat,
+						(unsigned char *)&src[i],
+						&auth_tok_list, &new_auth_tok,
+						&packet_size, max_packet_size);
+			if (rc) {
+				ecryptfs_printk(KERN_ERR, "Error parsing "
+						"tag 1 packet\n");
+				rc = -EIO;
+				goto out_wipe_list;
+			}
+			i += packet_size;
+			crypt_stat->flags |= ECRYPTFS_ENCRYPTED;
+			break;
+		case ECRYPTFS_TAG_11_PACKET_TYPE:
+			ecryptfs_printk(KERN_WARNING, "Invalid packet set "
+					"(Tag 11 not allowed by itself)\n");
+			rc = -EIO;
+			goto out_wipe_list;
+		default:
+			ecryptfs_printk(KERN_DEBUG, "No packet at offset [%zd] "
+					"of the file header; hex value of "
+					"character is [0x%.2x]\n", i, src[i]);
+			next_packet_is_auth_tok_packet = 0;
+		}
+	}
+	if (list_empty(&auth_tok_list)) {
+		printk(KERN_ERR "The lower file appears to be a non-encrypted "
+		       "eCryptfs file; this is not supported in this version "
+		       "of the eCryptfs kernel module\n");
+		rc = -EINVAL;
+		goto out;
+	}
+	/* auth_tok_list contains the set of authentication tokens
+	 * parsed from the metadata. We need to find a matching
+	 * authentication token that has the secret component(s)
+	 * necessary to decrypt the EFEK in the auth_tok parsed from
+	 * the metadata. There may be several potential matches, but
+	 * just one will be sufficient to decrypt to get the FEK. */
+find_next_matching_auth_tok:
+	found_auth_tok = 0;
+	list_for_each_entry(auth_tok_list_item, &auth_tok_list, list) {
+		candidate_auth_tok = &auth_tok_list_item->auth_tok;
+		if (unlikely(ecryptfs_verbosity > 0)) {
+			ecryptfs_printk(KERN_DEBUG,
+					"Considering candidate auth tok:\n");
+			ecryptfs_dump_auth_tok(candidate_auth_tok);
+		}
+		rc = ecryptfs_get_auth_tok_sig(&candidate_auth_tok_sig,
+					       candidate_auth_tok);
+		if (rc) {
+			printk(KERN_ERR
+			       "Unrecognized candidate auth tok type: [%d]\n",
+			       candidate_auth_tok->token_type);
+			rc = -EINVAL;
+			goto out_wipe_list;
+		}
+		rc = ecryptfs_find_auth_tok_for_sig(&auth_tok_key,
+					       &matching_auth_tok,
+					       crypt_stat->mount_crypt_stat,
+					       candidate_auth_tok_sig);
+		if (!rc) {
+			found_auth_tok = 1;
+			goto found_matching_auth_tok;
+		}
+	}
+	if (!found_auth_tok) {
+		ecryptfs_printk(KERN_ERR, "Could not find a usable "
+				"authentication token\n");
+		rc = -EIO;
+		goto out_wipe_list;
+	}
+found_matching_auth_tok:
+	if (candidate_auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
+		memcpy(&(candidate_auth_tok->token.private_key),
+		       &(matching_auth_tok->token.private_key),
+		       sizeof(struct ecryptfs_private_key));
+		up_write(&(auth_tok_key->sem));
+		key_put(auth_tok_key);
+		rc = decrypt_pki_encrypted_session_key(candidate_auth_tok,
+						       crypt_stat);
+	} else if (candidate_auth_tok->token_type == ECRYPTFS_PASSWORD) {
+		memcpy(&(candidate_auth_tok->token.password),
+		       &(matching_auth_tok->token.password),
+		       sizeof(struct ecryptfs_password));
+		up_write(&(auth_tok_key->sem));
+		key_put(auth_tok_key);
+		rc = decrypt_passphrase_encrypted_session_key(
+			candidate_auth_tok, crypt_stat);
+	} else {
+		up_write(&(auth_tok_key->sem));
+		key_put(auth_tok_key);
+		rc = -EINVAL;
+	}
+	if (rc) {
+		struct ecryptfs_auth_tok_list_item *auth_tok_list_item_tmp;
+
+		ecryptfs_printk(KERN_WARNING, "Error decrypting the "
+				"session key for authentication token with sig "
+				"[%.*s]; rc = [%d]. Removing auth tok "
+				"candidate from the list and searching for "
+				"the next match.\n", ECRYPTFS_SIG_SIZE_HEX,
+				candidate_auth_tok_sig,	rc);
+		list_for_each_entry_safe(auth_tok_list_item,
+					 auth_tok_list_item_tmp,
+					 &auth_tok_list, list) {
+			if (candidate_auth_tok
+			    == &auth_tok_list_item->auth_tok) {
+				list_del(&auth_tok_list_item->list);
+				kmem_cache_free(
+					ecryptfs_auth_tok_list_item_cache,
+					auth_tok_list_item);
+				goto find_next_matching_auth_tok;
+			}
+		}
+		BUG();
+	}
+	rc = ecryptfs_compute_root_iv(crypt_stat);
+	if (rc) {
+		ecryptfs_printk(KERN_ERR, "Error computing "
+				"the root IV\n");
+		goto out_wipe_list;
+	}
+	rc = ecryptfs_init_crypt_ctx(crypt_stat);
+	if (rc) {
+		ecryptfs_printk(KERN_ERR, "Error initializing crypto "
+				"context for cipher [%s]; rc = [%d]\n",
+				crypt_stat->cipher, rc);
+	}
+out_wipe_list:
+	wipe_auth_tok_list(&auth_tok_list);
+out:
+	return rc;
+}
+
+static int
+pki_encrypt_session_key(struct key *auth_tok_key,
+			struct ecryptfs_auth_tok *auth_tok,
+			struct ecryptfs_crypt_stat *crypt_stat,
+			struct ecryptfs_key_record *key_rec)
+{
+	struct ecryptfs_msg_ctx *msg_ctx = NULL;
+	char *payload = NULL;
+	size_t payload_len = 0;
+	struct ecryptfs_message *msg;
+	int rc;
+
+	rc = write_tag_66_packet(auth_tok->token.private_key.signature,
+				 ecryptfs_code_for_cipher_string(
+					 crypt_stat->cipher,
+					 crypt_stat->key_size),
+				 crypt_stat, &payload, &payload_len);
+	up_write(&(auth_tok_key->sem));
+	key_put(auth_tok_key);
+	if (rc) {
+		ecryptfs_printk(KERN_ERR, "Error generating tag 66 packet\n");
+		goto out;
+	}
+	rc = ecryptfs_send_message(payload, payload_len, &msg_ctx);
+	if (rc) {
+		ecryptfs_printk(KERN_ERR, "Error sending message to "
+				"ecryptfsd: %d\n", rc);
+		goto out;
+	}
+	rc = ecryptfs_wait_for_response(msg_ctx, &msg);
+	if (rc) {
+		ecryptfs_printk(KERN_ERR, "Failed to receive tag 67 packet "
+				"from the user space daemon\n");
+		rc = -EIO;
+		goto out;
+	}
+	rc = parse_tag_67_packet(key_rec, msg);
+	if (rc)
+		ecryptfs_printk(KERN_ERR, "Error parsing tag 67 packet\n");
+	kfree(msg);
+out:
+	kfree(payload);
+	return rc;
+}
+/**
+ * write_tag_1_packet - Write an RFC2440-compatible tag 1 (public key) packet
+ * @dest: Buffer into which to write the packet
+ * @remaining_bytes: Maximum number of bytes that can be writtn
+ * @auth_tok_key: The authentication token key to unlock and put when done with
+ *                @auth_tok
+ * @auth_tok: The authentication token used for generating the tag 1 packet
+ * @crypt_stat: The cryptographic context
+ * @key_rec: The key record struct for the tag 1 packet
+ * @packet_size: This function will write the number of bytes that end
+ *               up constituting the packet; set to zero on error
+ *
+ * Returns zero on success; non-zero on error.
+ */
+static int
+write_tag_1_packet(char *dest, size_t *remaining_bytes,
+		   struct key *auth_tok_key, struct ecryptfs_auth_tok *auth_tok,
+		   struct ecryptfs_crypt_stat *crypt_stat,
+		   struct ecryptfs_key_record *key_rec, size_t *packet_size)
+{
+	size_t i;
+	size_t encrypted_session_key_valid = 0;
+	size_t packet_size_length;
+	size_t max_packet_size;
+	int rc = 0;
+
+	(*packet_size) = 0;
+	ecryptfs_from_hex(key_rec->sig, auth_tok->token.private_key.signature,
+			  ECRYPTFS_SIG_SIZE);
+	encrypted_session_key_valid = 0;
+	for (i = 0; i < crypt_stat->key_size; i++)
+		encrypted_session_key_valid |=
+			auth_tok->session_key.encrypted_key[i];
+	if (encrypted_session_key_valid) {
+		memcpy(key_rec->enc_key,
+		       auth_tok->session_key.encrypted_key,
+		       auth_tok->session_key.encrypted_key_size);
+		up_write(&(auth_tok_key->sem));
+		key_put(auth_tok_key);
+		goto encrypted_session_key_set;
+	}
+	if (auth_tok->session_key.encrypted_key_size == 0)
+		auth_tok->session_key.encrypted_key_size =
+			auth_tok->token.private_key.key_size;
+	rc = pki_encrypt_session_key(auth_tok_key, auth_tok, crypt_stat,
+				     key_rec);
+	if (rc) {
+		printk(KERN_ERR "Failed to encrypt session key via a key "
+		       "module; rc = [%d]\n", rc);
+		goto out;
+	}
+	if (ecryptfs_verbosity > 0) {
+		ecryptfs_printk(KERN_DEBUG, "Encrypted key:\n");
+		ecryptfs_dump_hex(key_rec->enc_key, key_rec->enc_key_size);
+	}
+encrypted_session_key_set:
+	/* This format is inspired by OpenPGP; see RFC 2440
+	 * packet tag 1 */
+	max_packet_size = (1                         /* Tag 1 identifier */
+			   + 3                       /* Max Tag 1 packet size */
+			   + 1                       /* Version */
+			   + ECRYPTFS_SIG_SIZE       /* Key identifier */
+			   + 1                       /* Cipher identifier */
+			   + key_rec->enc_key_size); /* Encrypted key size */
+	if (max_packet_size > (*remaining_bytes)) {
+		printk(KERN_ERR "Packet length larger than maximum allowable; "
+		       "need up to [%td] bytes, but there are only [%td] "
+		       "available\n", max_packet_size, (*remaining_bytes));
+		rc = -EINVAL;
+		goto out;
+	}
+	dest[(*packet_size)++] = ECRYPTFS_TAG_1_PACKET_TYPE;
+	rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
+					  (max_packet_size - 4),
+					  &packet_size_length);
+	if (rc) {
+		ecryptfs_printk(KERN_ERR, "Error generating tag 1 packet "
+				"header; cannot generate packet length\n");
+		goto out;
+	}
+	(*packet_size) += packet_size_length;
+	dest[(*packet_size)++] = 0x03; /* version 3 */
+	memcpy(&dest[(*packet_size)], key_rec->sig, ECRYPTFS_SIG_SIZE);
+	(*packet_size) += ECRYPTFS_SIG_SIZE;
+	dest[(*packet_size)++] = RFC2440_CIPHER_RSA;
+	memcpy(&dest[(*packet_size)], key_rec->enc_key,
+	       key_rec->enc_key_size);
+	(*packet_size) += key_rec->enc_key_size;
+out:
+	if (rc)
+		(*packet_size) = 0;
+	else
+		(*remaining_bytes) -= (*packet_size);
+	return rc;
+}
+
+/**
+ * write_tag_11_packet
+ * @dest: Target into which Tag 11 packet is to be written
+ * @remaining_bytes: Maximum packet length
+ * @contents: Byte array of contents to copy in
+ * @contents_length: Number of bytes in contents
+ * @packet_length: Length of the Tag 11 packet written; zero on error
+ *
+ * Returns zero on success; non-zero on error.
+ */
+static int
+write_tag_11_packet(char *dest, size_t *remaining_bytes, char *contents,
+		    size_t contents_length, size_t *packet_length)
+{
+	size_t packet_size_length;
+	size_t max_packet_size;
+	int rc = 0;
+
+	(*packet_length) = 0;
+	/* This format is inspired by OpenPGP; see RFC 2440
+	 * packet tag 11 */
+	max_packet_size = (1                   /* Tag 11 identifier */
+			   + 3                 /* Max Tag 11 packet size */
+			   + 1                 /* Binary format specifier */
+			   + 1                 /* Filename length */
+			   + 8                 /* Filename ("_CONSOLE") */
+			   + 4                 /* Modification date */
+			   + contents_length); /* Literal data */
+	if (max_packet_size > (*remaining_bytes)) {
+		printk(KERN_ERR "Packet length larger than maximum allowable; "
+		       "need up to [%td] bytes, but there are only [%td] "
+		       "available\n", max_packet_size, (*remaining_bytes));
+		rc = -EINVAL;
+		goto out;
+	}
+	dest[(*packet_length)++] = ECRYPTFS_TAG_11_PACKET_TYPE;
+	rc = ecryptfs_write_packet_length(&dest[(*packet_length)],
+					  (max_packet_size - 4),
+					  &packet_size_length);
+	if (rc) {
+		printk(KERN_ERR "Error generating tag 11 packet header; cannot "
+		       "generate packet length. rc = [%d]\n", rc);
+		goto out;
+	}
+	(*packet_length) += packet_size_length;
+	dest[(*packet_length)++] = 0x62; /* binary data format specifier */
+	dest[(*packet_length)++] = 8;
+	memcpy(&dest[(*packet_length)], "_CONSOLE", 8);
+	(*packet_length) += 8;
+	memset(&dest[(*packet_length)], 0x00, 4);
+	(*packet_length) += 4;
+	memcpy(&dest[(*packet_length)], contents, contents_length);
+	(*packet_length) += contents_length;
+ out:
+	if (rc)
+		(*packet_length) = 0;
+	else
+		(*remaining_bytes) -= (*packet_length);
+	return rc;
+}
+
+/**
+ * write_tag_3_packet
+ * @dest: Buffer into which to write the packet
+ * @remaining_bytes: Maximum number of bytes that can be written
+ * @auth_tok: Authentication token
+ * @crypt_stat: The cryptographic context
+ * @key_rec: encrypted key
+ * @packet_size: This function will write the number of bytes that end
+ *               up constituting the packet; set to zero on error
+ *
+ * Returns zero on success; non-zero on error.
+ */
+static int
+write_tag_3_packet(char *dest, size_t *remaining_bytes,
+		   struct ecryptfs_auth_tok *auth_tok,
+		   struct ecryptfs_crypt_stat *crypt_stat,
+		   struct ecryptfs_key_record *key_rec, size_t *packet_size)
+{
+	size_t i;
+	size_t encrypted_session_key_valid = 0;
+	char session_key_encryption_key[ECRYPTFS_MAX_KEY_BYTES];
+	struct scatterlist dst_sg[2];
+	struct scatterlist src_sg[2];
+	struct mutex *tfm_mutex = NULL;
+	u8 cipher_code;
+	size_t packet_size_length;
+	size_t max_packet_size;
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
+		crypt_stat->mount_crypt_stat;
+	struct crypto_skcipher *tfm;
+	struct skcipher_request *req;
+	int rc = 0;
+
+	(*packet_size) = 0;
+	ecryptfs_from_hex(key_rec->sig, auth_tok->token.password.signature,
+			  ECRYPTFS_SIG_SIZE);
+	rc = ecryptfs_get_tfm_and_mutex_for_cipher_name(&tfm, &tfm_mutex,
+							crypt_stat->cipher);
+	if (unlikely(rc)) {
+		printk(KERN_ERR "Internal error whilst attempting to get "
+		       "tfm and mutex for cipher name [%s]; rc = [%d]\n",
+		       crypt_stat->cipher, rc);
+		goto out;
+	}
+	if (mount_crypt_stat->global_default_cipher_key_size == 0) {
+		printk(KERN_WARNING "No key size specified at mount; "
+		       "defaulting to [%d]\n",
+		       crypto_skcipher_max_keysize(tfm));
+		mount_crypt_stat->global_default_cipher_key_size =
+			crypto_skcipher_max_keysize(tfm);
+	}
+	if (crypt_stat->key_size == 0)
+		crypt_stat->key_size =
+			mount_crypt_stat->global_default_cipher_key_size;
+	if (auth_tok->session_key.encrypted_key_size == 0)
+		auth_tok->session_key.encrypted_key_size =
+			crypt_stat->key_size;
+	if (crypt_stat->key_size == 24
+	    && strcmp("aes", crypt_stat->cipher) == 0) {
+		memset((crypt_stat->key + 24), 0, 8);
+		auth_tok->session_key.encrypted_key_size = 32;
+	} else
+		auth_tok->session_key.encrypted_key_size = crypt_stat->key_size;
+	key_rec->enc_key_size =
+		auth_tok->session_key.encrypted_key_size;
+	encrypted_session_key_valid = 0;
+	for (i = 0; i < auth_tok->session_key.encrypted_key_size; i++)
+		encrypted_session_key_valid |=
+			auth_tok->session_key.encrypted_key[i];
+	if (encrypted_session_key_valid) {
+		ecryptfs_printk(KERN_DEBUG, "encrypted_session_key_valid != 0; "
+				"using auth_tok->session_key.encrypted_key, "
+				"where key_rec->enc_key_size = [%zd]\n",
+				key_rec->enc_key_size);
+		memcpy(key_rec->enc_key,
+		       auth_tok->session_key.encrypted_key,
+		       key_rec->enc_key_size);
+		goto encrypted_session_key_set;
+	}
+	if (auth_tok->token.password.flags &
+	    ECRYPTFS_SESSION_KEY_ENCRYPTION_KEY_SET) {
+		ecryptfs_printk(KERN_DEBUG, "Using previously generated "
+				"session key encryption key of size [%d]\n",
+				auth_tok->token.password.
+				session_key_encryption_key_bytes);
+		memcpy(session_key_encryption_key,
+		       auth_tok->token.password.session_key_encryption_key,
+		       crypt_stat->key_size);
+		ecryptfs_printk(KERN_DEBUG,
+				"Cached session key encryption key:\n");
+		if (ecryptfs_verbosity > 0)
+			ecryptfs_dump_hex(session_key_encryption_key, 16);
+	}
+	if (unlikely(ecryptfs_verbosity > 0)) {
+		ecryptfs_printk(KERN_DEBUG, "Session key encryption key:\n");
+		ecryptfs_dump_hex(session_key_encryption_key, 16);
+	}
+	rc = virt_to_scatterlist(crypt_stat->key, key_rec->enc_key_size,
+				 src_sg, 2);
+	if (rc < 1 || rc > 2) {
+		ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
+				"for crypt_stat session key; expected rc = 1; "
+				"got rc = [%d]. key_rec->enc_key_size = [%zd]\n",
+				rc, key_rec->enc_key_size);
+		rc = -ENOMEM;
+		goto out;
+	}
+	rc = virt_to_scatterlist(key_rec->enc_key, key_rec->enc_key_size,
+				 dst_sg, 2);
+	if (rc < 1 || rc > 2) {
+		ecryptfs_printk(KERN_ERR, "Error generating scatterlist "
+				"for crypt_stat encrypted session key; "
+				"expected rc = 1; got rc = [%d]. "
+				"key_rec->enc_key_size = [%zd]\n", rc,
+				key_rec->enc_key_size);
+		rc = -ENOMEM;
+		goto out;
+	}
+	mutex_lock(tfm_mutex);
+	rc = crypto_skcipher_setkey(tfm, session_key_encryption_key,
+				    crypt_stat->key_size);
+	if (rc < 0) {
+		mutex_unlock(tfm_mutex);
+		ecryptfs_printk(KERN_ERR, "Error setting key for crypto "
+				"context; rc = [%d]\n", rc);
+		goto out;
+	}
+
+	req = skcipher_request_alloc(tfm, GFP_KERNEL);
+	if (!req) {
+		mutex_unlock(tfm_mutex);
+		ecryptfs_printk(KERN_ERR, "Out of kernel memory whilst "
+				"attempting to skcipher_request_alloc for "
+				"%s\n", crypto_skcipher_driver_name(tfm));
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	skcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP,
+				      NULL, NULL);
+
+	rc = 0;
+	ecryptfs_printk(KERN_DEBUG, "Encrypting [%zd] bytes of the key\n",
+			crypt_stat->key_size);
+	skcipher_request_set_crypt(req, src_sg, dst_sg,
+				   (*key_rec).enc_key_size, NULL);
+	rc = crypto_skcipher_encrypt(req);
+	mutex_unlock(tfm_mutex);
+	skcipher_request_free(req);
+	if (rc) {
+		printk(KERN_ERR "Error encrypting; rc = [%d]\n", rc);
+		goto out;
+	}
+	ecryptfs_printk(KERN_DEBUG, "This should be the encrypted key:\n");
+	if (ecryptfs_verbosity > 0) {
+		ecryptfs_printk(KERN_DEBUG, "EFEK of size [%zd]:\n",
+				key_rec->enc_key_size);
+		ecryptfs_dump_hex(key_rec->enc_key,
+				  key_rec->enc_key_size);
+	}
+encrypted_session_key_set:
+	/* This format is inspired by OpenPGP; see RFC 2440
+	 * packet tag 3 */
+	max_packet_size = (1                         /* Tag 3 identifier */
+			   + 3                       /* Max Tag 3 packet size */
+			   + 1                       /* Version */
+			   + 1                       /* Cipher code */
+			   + 1                       /* S2K specifier */
+			   + 1                       /* Hash identifier */
+			   + ECRYPTFS_SALT_SIZE      /* Salt */
+			   + 1                       /* Hash iterations */
+			   + key_rec->enc_key_size); /* Encrypted key size */
+	if (max_packet_size > (*remaining_bytes)) {
+		printk(KERN_ERR "Packet too large; need up to [%td] bytes, but "
+		       "there are only [%td] available\n", max_packet_size,
+		       (*remaining_bytes));
+		rc = -EINVAL;
+		goto out;
+	}
+	dest[(*packet_size)++] = ECRYPTFS_TAG_3_PACKET_TYPE;
+	/* Chop off the Tag 3 identifier(1) and Tag 3 packet size(3)
+	 * to get the number of octets in the actual Tag 3 packet */
+	rc = ecryptfs_write_packet_length(&dest[(*packet_size)],
+					  (max_packet_size - 4),
+					  &packet_size_length);
+	if (rc) {
+		printk(KERN_ERR "Error generating tag 3 packet header; cannot "
+		       "generate packet length. rc = [%d]\n", rc);
+		goto out;
+	}
+	(*packet_size) += packet_size_length;
+	dest[(*packet_size)++] = 0x04; /* version 4 */
+	/* TODO: Break from RFC2440 so that arbitrary ciphers can be
+	 * specified with strings */
+	cipher_code = ecryptfs_code_for_cipher_string(crypt_stat->cipher,
+						      crypt_stat->key_size);
+	if (cipher_code == 0) {
+		ecryptfs_printk(KERN_WARNING, "Unable to generate code for "
+				"cipher [%s]\n", crypt_stat->cipher);
+		rc = -EINVAL;
+		goto out;
+	}
+	dest[(*packet_size)++] = cipher_code;
+	dest[(*packet_size)++] = 0x03;	/* S2K */
+	dest[(*packet_size)++] = 0x01;	/* MD5 (TODO: parameterize) */
+	memcpy(&dest[(*packet_size)], auth_tok->token.password.salt,
+	       ECRYPTFS_SALT_SIZE);
+	(*packet_size) += ECRYPTFS_SALT_SIZE;	/* salt */
+	dest[(*packet_size)++] = 0x60;	/* hash iterations (65536) */
+	memcpy(&dest[(*packet_size)], key_rec->enc_key,
+	       key_rec->enc_key_size);
+	(*packet_size) += key_rec->enc_key_size;
+out:
+	if (rc)
+		(*packet_size) = 0;
+	else
+		(*remaining_bytes) -= (*packet_size);
+	return rc;
+}
+
+struct kmem_cache *ecryptfs_key_record_cache;
+
+/**
+ * ecryptfs_generate_key_packet_set
+ * @dest_base: Virtual address from which to write the key record set
+ * @crypt_stat: The cryptographic context from which the
+ *              authentication tokens will be retrieved
+ * @ecryptfs_dentry: The dentry, used to retrieve the mount crypt stat
+ *                   for the global parameters
+ * @len: The amount written
+ * @max: The maximum amount of data allowed to be written
+ *
+ * Generates a key packet set and writes it to the virtual address
+ * passed in.
+ *
+ * Returns zero on success; non-zero on error.
+ */
+int
+ecryptfs_generate_key_packet_set(char *dest_base,
+				 struct ecryptfs_crypt_stat *crypt_stat,
+				 struct dentry *ecryptfs_dentry, size_t *len,
+				 size_t max)
+{
+	struct ecryptfs_auth_tok *auth_tok;
+	struct key *auth_tok_key = NULL;
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
+		&ecryptfs_superblock_to_private(
+			ecryptfs_dentry->d_sb)->mount_crypt_stat;
+	size_t written;
+	struct ecryptfs_key_record *key_rec;
+	struct ecryptfs_key_sig *key_sig;
+	int rc = 0;
+
+	(*len) = 0;
+	mutex_lock(&crypt_stat->keysig_list_mutex);
+	key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
+	if (!key_rec) {
+		rc = -ENOMEM;
+		goto out;
+	}
+	list_for_each_entry(key_sig, &crypt_stat->keysig_list,
+			    crypt_stat_list) {
+		memset(key_rec, 0, sizeof(*key_rec));
+		rc = ecryptfs_find_global_auth_tok_for_sig(&auth_tok_key,
+							   &auth_tok,
+							   mount_crypt_stat,
+							   key_sig->keysig);
+		if (rc) {
+			printk(KERN_WARNING "Unable to retrieve auth tok with "
+			       "sig = [%s]\n", key_sig->keysig);
+			rc = process_find_global_auth_tok_for_sig_err(rc);
+			goto out_free;
+		}
+		if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
+			rc = write_tag_3_packet((dest_base + (*len)),
+						&max, auth_tok,
+						crypt_stat, key_rec,
+						&written);
+			up_write(&(auth_tok_key->sem));
+			key_put(auth_tok_key);
+			if (rc) {
+				ecryptfs_printk(KERN_WARNING, "Error "
+						"writing tag 3 packet\n");
+				goto out_free;
+			}
+			(*len) += written;
+			/* Write auth tok signature packet */
+			rc = write_tag_11_packet((dest_base + (*len)), &max,
+						 key_rec->sig,
+						 ECRYPTFS_SIG_SIZE, &written);
+			if (rc) {
+				ecryptfs_printk(KERN_ERR, "Error writing "
+						"auth tok signature packet\n");
+				goto out_free;
+			}
+			(*len) += written;
+		} else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
+			rc = write_tag_1_packet(dest_base + (*len), &max,
+						auth_tok_key, auth_tok,
+						crypt_stat, key_rec, &written);
+			if (rc) {
+				ecryptfs_printk(KERN_WARNING, "Error "
+						"writing tag 1 packet\n");
+				goto out_free;
+			}
+			(*len) += written;
+		} else {
+			up_write(&(auth_tok_key->sem));
+			key_put(auth_tok_key);
+			ecryptfs_printk(KERN_WARNING, "Unsupported "
+					"authentication token type\n");
+			rc = -EINVAL;
+			goto out_free;
+		}
+	}
+	if (likely(max > 0)) {
+		dest_base[(*len)] = 0x00;
+	} else {
+		ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
+		rc = -EIO;
+	}
+out_free:
+	kmem_cache_free(ecryptfs_key_record_cache, key_rec);
+out:
+	if (rc)
+		(*len) = 0;
+	mutex_unlock(&crypt_stat->keysig_list_mutex);
+	return rc;
+}
+
+struct kmem_cache *ecryptfs_key_sig_cache;
+
+int ecryptfs_add_keysig(struct ecryptfs_crypt_stat *crypt_stat, char *sig)
+{
+	struct ecryptfs_key_sig *new_key_sig;
+
+	new_key_sig = kmem_cache_alloc(ecryptfs_key_sig_cache, GFP_KERNEL);
+	if (!new_key_sig)
+		return -ENOMEM;
+
+	memcpy(new_key_sig->keysig, sig, ECRYPTFS_SIG_SIZE_HEX);
+	new_key_sig->keysig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
+	/* Caller must hold keysig_list_mutex */
+	list_add(&new_key_sig->crypt_stat_list, &crypt_stat->keysig_list);
+
+	return 0;
+}
+
+struct kmem_cache *ecryptfs_global_auth_tok_cache;
+
+int
+ecryptfs_add_global_auth_tok(struct ecryptfs_mount_crypt_stat *mount_crypt_stat,
+			     char *sig, u32 global_auth_tok_flags)
+{
+	struct ecryptfs_global_auth_tok *new_auth_tok;
+
+	new_auth_tok = kmem_cache_zalloc(ecryptfs_global_auth_tok_cache,
+					GFP_KERNEL);
+	if (!new_auth_tok)
+		return -ENOMEM;
+
+	memcpy(new_auth_tok->sig, sig, ECRYPTFS_SIG_SIZE_HEX);
+	new_auth_tok->flags = global_auth_tok_flags;
+	new_auth_tok->sig[ECRYPTFS_SIG_SIZE_HEX] = '\0';
+	mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
+	list_add(&new_auth_tok->mount_crypt_stat_list,
+		 &mount_crypt_stat->global_auth_tok_list);
+	mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
+	return 0;
+}
+
diff --git a/fs/ecryptfs/kthread.c b/fs/ecryptfs/kthread.c
new file mode 100644
index 000000000..ae4cb4e2e
--- /dev/null
+++ b/fs/ecryptfs/kthread.c
@@ -0,0 +1,159 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 2008 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
+ */
+
+#include <linux/kthread.h>
+#include <linux/freezer.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+#include <linux/mount.h>
+#include "ecryptfs_kernel.h"
+
+struct ecryptfs_open_req {
+	struct file **lower_file;
+	struct path path;
+	struct completion done;
+	struct list_head kthread_ctl_list;
+};
+
+static struct ecryptfs_kthread_ctl {
+#define ECRYPTFS_KTHREAD_ZOMBIE 0x00000001
+	u32 flags;
+	struct mutex mux;
+	struct list_head req_list;
+	wait_queue_head_t wait;
+} ecryptfs_kthread_ctl;
+
+static struct task_struct *ecryptfs_kthread;
+
+/**
+ * ecryptfs_threadfn
+ * @ignored: ignored
+ *
+ * The eCryptfs kernel thread that has the responsibility of getting
+ * the lower file with RW permissions.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int ecryptfs_threadfn(void *ignored)
+{
+	set_freezable();
+	while (1)  {
+		struct ecryptfs_open_req *req;
+
+		wait_event_freezable(
+			ecryptfs_kthread_ctl.wait,
+			(!list_empty(&ecryptfs_kthread_ctl.req_list)
+			 || kthread_should_stop()));
+		mutex_lock(&ecryptfs_kthread_ctl.mux);
+		if (ecryptfs_kthread_ctl.flags & ECRYPTFS_KTHREAD_ZOMBIE) {
+			mutex_unlock(&ecryptfs_kthread_ctl.mux);
+			goto out;
+		}
+		while (!list_empty(&ecryptfs_kthread_ctl.req_list)) {
+			req = list_first_entry(&ecryptfs_kthread_ctl.req_list,
+					       struct ecryptfs_open_req,
+					       kthread_ctl_list);
+			list_del(&req->kthread_ctl_list);
+			*req->lower_file = dentry_open(&req->path,
+				(O_RDWR | O_LARGEFILE), current_cred());
+			complete(&req->done);
+		}
+		mutex_unlock(&ecryptfs_kthread_ctl.mux);
+	}
+out:
+	return 0;
+}
+
+int __init ecryptfs_init_kthread(void)
+{
+	int rc = 0;
+
+	mutex_init(&ecryptfs_kthread_ctl.mux);
+	init_waitqueue_head(&ecryptfs_kthread_ctl.wait);
+	INIT_LIST_HEAD(&ecryptfs_kthread_ctl.req_list);
+	ecryptfs_kthread = kthread_run(&ecryptfs_threadfn, NULL,
+				       "ecryptfs-kthread");
+	if (IS_ERR(ecryptfs_kthread)) {
+		rc = PTR_ERR(ecryptfs_kthread);
+		printk(KERN_ERR "%s: Failed to create kernel thread; rc = [%d]"
+		       "\n", __func__, rc);
+	}
+	return rc;
+}
+
+void ecryptfs_destroy_kthread(void)
+{
+	struct ecryptfs_open_req *req, *tmp;
+
+	mutex_lock(&ecryptfs_kthread_ctl.mux);
+	ecryptfs_kthread_ctl.flags |= ECRYPTFS_KTHREAD_ZOMBIE;
+	list_for_each_entry_safe(req, tmp, &ecryptfs_kthread_ctl.req_list,
+				 kthread_ctl_list) {
+		list_del(&req->kthread_ctl_list);
+		*req->lower_file = ERR_PTR(-EIO);
+		complete(&req->done);
+	}
+	mutex_unlock(&ecryptfs_kthread_ctl.mux);
+	kthread_stop(ecryptfs_kthread);
+	wake_up(&ecryptfs_kthread_ctl.wait);
+}
+
+/**
+ * ecryptfs_privileged_open
+ * @lower_file: Result of dentry_open by root on lower dentry
+ * @lower_dentry: Lower dentry for file to open
+ * @lower_mnt: Lower vfsmount for file to open
+ * @cred: credential to use for this call
+ *
+ * This function gets a r/w file opened against the lower dentry.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int ecryptfs_privileged_open(struct file **lower_file,
+			     struct dentry *lower_dentry,
+			     struct vfsmount *lower_mnt,
+			     const struct cred *cred)
+{
+	struct ecryptfs_open_req req;
+	int flags = O_LARGEFILE;
+	int rc = 0;
+
+	init_completion(&req.done);
+	req.lower_file = lower_file;
+	req.path.dentry = lower_dentry;
+	req.path.mnt = lower_mnt;
+
+	/* Corresponding dput() and mntput() are done when the
+	 * lower file is fput() when all eCryptfs files for the inode are
+	 * released. */
+	flags |= IS_RDONLY(d_inode(lower_dentry)) ? O_RDONLY : O_RDWR;
+	(*lower_file) = dentry_open(&req.path, flags, cred);
+	if (!IS_ERR(*lower_file))
+		goto out;
+	if ((flags & O_ACCMODE) == O_RDONLY) {
+		rc = PTR_ERR((*lower_file));
+		goto out;
+	}
+	mutex_lock(&ecryptfs_kthread_ctl.mux);
+	if (ecryptfs_kthread_ctl.flags & ECRYPTFS_KTHREAD_ZOMBIE) {
+		rc = -EIO;
+		mutex_unlock(&ecryptfs_kthread_ctl.mux);
+		printk(KERN_ERR "%s: We are in the middle of shutting down; "
+		       "aborting privileged request to open lower file\n",
+			__func__);
+		goto out;
+	}
+	list_add_tail(&req.kthread_ctl_list, &ecryptfs_kthread_ctl.req_list);
+	mutex_unlock(&ecryptfs_kthread_ctl.mux);
+	wake_up(&ecryptfs_kthread_ctl.wait);
+	wait_for_completion(&req.done);
+	if (IS_ERR(*lower_file))
+		rc = PTR_ERR(*lower_file);
+out:
+	return rc;
+}
diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
new file mode 100644
index 000000000..2dc927ba0
--- /dev/null
+++ b/fs/ecryptfs/main.c
@@ -0,0 +1,902 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 1997-2003 Erez Zadok
+ * Copyright (C) 2001-2003 Stony Brook University
+ * Copyright (C) 2004-2007 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
+ *              Michael C. Thompson <mcthomps@us.ibm.com>
+ *              Tyler Hicks <code@tyhicks.com>
+ */
+
+#include <linux/dcache.h>
+#include <linux/file.h>
+#include <linux/module.h>
+#include <linux/namei.h>
+#include <linux/skbuff.h>
+#include <linux/mount.h>
+#include <linux/pagemap.h>
+#include <linux/key.h>
+#include <linux/parser.h>
+#include <linux/fs_stack.h>
+#include <linux/slab.h>
+#include <linux/magic.h>
+#include "ecryptfs_kernel.h"
+
+/*
+ * Module parameter that defines the ecryptfs_verbosity level.
+ */
+int ecryptfs_verbosity = 0;
+
+module_param(ecryptfs_verbosity, int, 0);
+MODULE_PARM_DESC(ecryptfs_verbosity,
+		 "Initial verbosity level (0 or 1; defaults to "
+		 "0, which is Quiet)");
+
+/*
+ * Module parameter that defines the number of message buffer elements
+ */
+unsigned int ecryptfs_message_buf_len = ECRYPTFS_DEFAULT_MSG_CTX_ELEMS;
+
+module_param(ecryptfs_message_buf_len, uint, 0);
+MODULE_PARM_DESC(ecryptfs_message_buf_len,
+		 "Number of message buffer elements");
+
+/*
+ * Module parameter that defines the maximum guaranteed amount of time to wait
+ * for a response from ecryptfsd.  The actual sleep time will be, more than
+ * likely, a small amount greater than this specified value, but only less if
+ * the message successfully arrives.
+ */
+signed long ecryptfs_message_wait_timeout = ECRYPTFS_MAX_MSG_CTX_TTL / HZ;
+
+module_param(ecryptfs_message_wait_timeout, long, 0);
+MODULE_PARM_DESC(ecryptfs_message_wait_timeout,
+		 "Maximum number of seconds that an operation will "
+		 "sleep while waiting for a message response from "
+		 "userspace");
+
+/*
+ * Module parameter that is an estimate of the maximum number of users
+ * that will be concurrently using eCryptfs. Set this to the right
+ * value to balance performance and memory use.
+ */
+unsigned int ecryptfs_number_of_users = ECRYPTFS_DEFAULT_NUM_USERS;
+
+module_param(ecryptfs_number_of_users, uint, 0);
+MODULE_PARM_DESC(ecryptfs_number_of_users, "An estimate of the number of "
+		 "concurrent users of eCryptfs");
+
+void __ecryptfs_printk(const char *fmt, ...)
+{
+	va_list args;
+	va_start(args, fmt);
+	if (fmt[1] == '7') { /* KERN_DEBUG */
+		if (ecryptfs_verbosity >= 1)
+			vprintk(fmt, args);
+	} else
+		vprintk(fmt, args);
+	va_end(args);
+}
+
+/*
+ * ecryptfs_init_lower_file
+ * @ecryptfs_dentry: Fully initialized eCryptfs dentry object, with
+ *                   the lower dentry and the lower mount set
+ *
+ * eCryptfs only ever keeps a single open file for every lower
+ * inode. All I/O operations to the lower inode occur through that
+ * file. When the first eCryptfs dentry that interposes with the first
+ * lower dentry for that inode is created, this function creates the
+ * lower file struct and associates it with the eCryptfs
+ * inode. When all eCryptfs files associated with the inode are released, the
+ * file is closed.
+ *
+ * The lower file will be opened with read/write permissions, if
+ * possible. Otherwise, it is opened read-only.
+ *
+ * This function does nothing if a lower file is already
+ * associated with the eCryptfs inode.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int ecryptfs_init_lower_file(struct dentry *dentry,
+				    struct file **lower_file)
+{
+	const struct cred *cred = current_cred();
+	const struct path *path = ecryptfs_dentry_to_lower_path(dentry);
+	int rc;
+
+	rc = ecryptfs_privileged_open(lower_file, path->dentry, path->mnt,
+				      cred);
+	if (rc) {
+		printk(KERN_ERR "Error opening lower file "
+		       "for lower_dentry [0x%p] and lower_mnt [0x%p]; "
+		       "rc = [%d]\n", path->dentry, path->mnt, rc);
+		(*lower_file) = NULL;
+	}
+	return rc;
+}
+
+int ecryptfs_get_lower_file(struct dentry *dentry, struct inode *inode)
+{
+	struct ecryptfs_inode_info *inode_info;
+	int count, rc = 0;
+
+	inode_info = ecryptfs_inode_to_private(inode);
+	mutex_lock(&inode_info->lower_file_mutex);
+	count = atomic_inc_return(&inode_info->lower_file_count);
+	if (WARN_ON_ONCE(count < 1))
+		rc = -EINVAL;
+	else if (count == 1) {
+		rc = ecryptfs_init_lower_file(dentry,
+					      &inode_info->lower_file);
+		if (rc)
+			atomic_set(&inode_info->lower_file_count, 0);
+	}
+	mutex_unlock(&inode_info->lower_file_mutex);
+	return rc;
+}
+
+void ecryptfs_put_lower_file(struct inode *inode)
+{
+	struct ecryptfs_inode_info *inode_info;
+
+	inode_info = ecryptfs_inode_to_private(inode);
+	if (atomic_dec_and_mutex_lock(&inode_info->lower_file_count,
+				      &inode_info->lower_file_mutex)) {
+		filemap_write_and_wait(inode->i_mapping);
+		fput(inode_info->lower_file);
+		inode_info->lower_file = NULL;
+		mutex_unlock(&inode_info->lower_file_mutex);
+	}
+}
+
+enum { ecryptfs_opt_sig, ecryptfs_opt_ecryptfs_sig,
+       ecryptfs_opt_cipher, ecryptfs_opt_ecryptfs_cipher,
+       ecryptfs_opt_ecryptfs_key_bytes,
+       ecryptfs_opt_passthrough, ecryptfs_opt_xattr_metadata,
+       ecryptfs_opt_encrypted_view, ecryptfs_opt_fnek_sig,
+       ecryptfs_opt_fn_cipher, ecryptfs_opt_fn_cipher_key_bytes,
+       ecryptfs_opt_unlink_sigs, ecryptfs_opt_mount_auth_tok_only,
+       ecryptfs_opt_check_dev_ruid,
+       ecryptfs_opt_err };
+
+static const match_table_t tokens = {
+	{ecryptfs_opt_sig, "sig=%s"},
+	{ecryptfs_opt_ecryptfs_sig, "ecryptfs_sig=%s"},
+	{ecryptfs_opt_cipher, "cipher=%s"},
+	{ecryptfs_opt_ecryptfs_cipher, "ecryptfs_cipher=%s"},
+	{ecryptfs_opt_ecryptfs_key_bytes, "ecryptfs_key_bytes=%u"},
+	{ecryptfs_opt_passthrough, "ecryptfs_passthrough"},
+	{ecryptfs_opt_xattr_metadata, "ecryptfs_xattr_metadata"},
+	{ecryptfs_opt_encrypted_view, "ecryptfs_encrypted_view"},
+	{ecryptfs_opt_fnek_sig, "ecryptfs_fnek_sig=%s"},
+	{ecryptfs_opt_fn_cipher, "ecryptfs_fn_cipher=%s"},
+	{ecryptfs_opt_fn_cipher_key_bytes, "ecryptfs_fn_key_bytes=%u"},
+	{ecryptfs_opt_unlink_sigs, "ecryptfs_unlink_sigs"},
+	{ecryptfs_opt_mount_auth_tok_only, "ecryptfs_mount_auth_tok_only"},
+	{ecryptfs_opt_check_dev_ruid, "ecryptfs_check_dev_ruid"},
+	{ecryptfs_opt_err, NULL}
+};
+
+static int ecryptfs_init_global_auth_toks(
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
+{
+	struct ecryptfs_global_auth_tok *global_auth_tok;
+	struct ecryptfs_auth_tok *auth_tok;
+	int rc = 0;
+
+	list_for_each_entry(global_auth_tok,
+			    &mount_crypt_stat->global_auth_tok_list,
+			    mount_crypt_stat_list) {
+		rc = ecryptfs_keyring_auth_tok_for_sig(
+			&global_auth_tok->global_auth_tok_key, &auth_tok,
+			global_auth_tok->sig);
+		if (rc) {
+			printk(KERN_ERR "Could not find valid key in user "
+			       "session keyring for sig specified in mount "
+			       "option: [%s]\n", global_auth_tok->sig);
+			global_auth_tok->flags |= ECRYPTFS_AUTH_TOK_INVALID;
+			goto out;
+		} else {
+			global_auth_tok->flags &= ~ECRYPTFS_AUTH_TOK_INVALID;
+			up_write(&(global_auth_tok->global_auth_tok_key)->sem);
+		}
+	}
+out:
+	return rc;
+}
+
+static void ecryptfs_init_mount_crypt_stat(
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat)
+{
+	memset((void *)mount_crypt_stat, 0,
+	       sizeof(struct ecryptfs_mount_crypt_stat));
+	INIT_LIST_HEAD(&mount_crypt_stat->global_auth_tok_list);
+	mutex_init(&mount_crypt_stat->global_auth_tok_list_mutex);
+	mount_crypt_stat->flags |= ECRYPTFS_MOUNT_CRYPT_STAT_INITIALIZED;
+}
+
+/**
+ * ecryptfs_parse_options
+ * @sbi: The ecryptfs super block
+ * @options: The options passed to the kernel
+ * @check_ruid: set to 1 if device uid should be checked against the ruid
+ *
+ * Parse mount options:
+ * debug=N 	   - ecryptfs_verbosity level for debug output
+ * sig=XXX	   - description(signature) of the key to use
+ *
+ * Returns the dentry object of the lower-level (lower/interposed)
+ * directory; We want to mount our stackable file system on top of
+ * that lower directory.
+ *
+ * The signature of the key to use must be the description of a key
+ * already in the keyring. Mounting will fail if the key can not be
+ * found.
+ *
+ * Returns zero on success; non-zero on error
+ */
+static int ecryptfs_parse_options(struct ecryptfs_sb_info *sbi, char *options,
+				  uid_t *check_ruid)
+{
+	char *p;
+	int rc = 0;
+	int sig_set = 0;
+	int cipher_name_set = 0;
+	int fn_cipher_name_set = 0;
+	int cipher_key_bytes;
+	int cipher_key_bytes_set = 0;
+	int fn_cipher_key_bytes;
+	int fn_cipher_key_bytes_set = 0;
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
+		&sbi->mount_crypt_stat;
+	substring_t args[MAX_OPT_ARGS];
+	int token;
+	char *sig_src;
+	char *cipher_name_dst;
+	char *cipher_name_src;
+	char *fn_cipher_name_dst;
+	char *fn_cipher_name_src;
+	char *fnek_dst;
+	char *fnek_src;
+	char *cipher_key_bytes_src;
+	char *fn_cipher_key_bytes_src;
+	u8 cipher_code;
+
+	*check_ruid = 0;
+
+	if (!options) {
+		rc = -EINVAL;
+		goto out;
+	}
+	ecryptfs_init_mount_crypt_stat(mount_crypt_stat);
+	while ((p = strsep(&options, ",")) != NULL) {
+		if (!*p)
+			continue;
+		token = match_token(p, tokens, args);
+		switch (token) {
+		case ecryptfs_opt_sig:
+		case ecryptfs_opt_ecryptfs_sig:
+			sig_src = args[0].from;
+			rc = ecryptfs_add_global_auth_tok(mount_crypt_stat,
+							  sig_src, 0);
+			if (rc) {
+				printk(KERN_ERR "Error attempting to register "
+				       "global sig; rc = [%d]\n", rc);
+				goto out;
+			}
+			sig_set = 1;
+			break;
+		case ecryptfs_opt_cipher:
+		case ecryptfs_opt_ecryptfs_cipher:
+			cipher_name_src = args[0].from;
+			cipher_name_dst =
+				mount_crypt_stat->
+				global_default_cipher_name;
+			strncpy(cipher_name_dst, cipher_name_src,
+				ECRYPTFS_MAX_CIPHER_NAME_SIZE);
+			cipher_name_dst[ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
+			cipher_name_set = 1;
+			break;
+		case ecryptfs_opt_ecryptfs_key_bytes:
+			cipher_key_bytes_src = args[0].from;
+			cipher_key_bytes =
+				(int)simple_strtol(cipher_key_bytes_src,
+						   &cipher_key_bytes_src, 0);
+			mount_crypt_stat->global_default_cipher_key_size =
+				cipher_key_bytes;
+			cipher_key_bytes_set = 1;
+			break;
+		case ecryptfs_opt_passthrough:
+			mount_crypt_stat->flags |=
+				ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED;
+			break;
+		case ecryptfs_opt_xattr_metadata:
+			mount_crypt_stat->flags |=
+				ECRYPTFS_XATTR_METADATA_ENABLED;
+			break;
+		case ecryptfs_opt_encrypted_view:
+			mount_crypt_stat->flags |=
+				ECRYPTFS_XATTR_METADATA_ENABLED;
+			mount_crypt_stat->flags |=
+				ECRYPTFS_ENCRYPTED_VIEW_ENABLED;
+			break;
+		case ecryptfs_opt_fnek_sig:
+			fnek_src = args[0].from;
+			fnek_dst =
+				mount_crypt_stat->global_default_fnek_sig;
+			strncpy(fnek_dst, fnek_src, ECRYPTFS_SIG_SIZE_HEX);
+			mount_crypt_stat->global_default_fnek_sig[
+				ECRYPTFS_SIG_SIZE_HEX] = '\0';
+			rc = ecryptfs_add_global_auth_tok(
+				mount_crypt_stat,
+				mount_crypt_stat->global_default_fnek_sig,
+				ECRYPTFS_AUTH_TOK_FNEK);
+			if (rc) {
+				printk(KERN_ERR "Error attempting to register "
+				       "global fnek sig [%s]; rc = [%d]\n",
+				       mount_crypt_stat->global_default_fnek_sig,
+				       rc);
+				goto out;
+			}
+			mount_crypt_stat->flags |=
+				(ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES
+				 | ECRYPTFS_GLOBAL_ENCFN_USE_MOUNT_FNEK);
+			break;
+		case ecryptfs_opt_fn_cipher:
+			fn_cipher_name_src = args[0].from;
+			fn_cipher_name_dst =
+				mount_crypt_stat->global_default_fn_cipher_name;
+			strncpy(fn_cipher_name_dst, fn_cipher_name_src,
+				ECRYPTFS_MAX_CIPHER_NAME_SIZE);
+			mount_crypt_stat->global_default_fn_cipher_name[
+				ECRYPTFS_MAX_CIPHER_NAME_SIZE] = '\0';
+			fn_cipher_name_set = 1;
+			break;
+		case ecryptfs_opt_fn_cipher_key_bytes:
+			fn_cipher_key_bytes_src = args[0].from;
+			fn_cipher_key_bytes =
+				(int)simple_strtol(fn_cipher_key_bytes_src,
+						   &fn_cipher_key_bytes_src, 0);
+			mount_crypt_stat->global_default_fn_cipher_key_bytes =
+				fn_cipher_key_bytes;
+			fn_cipher_key_bytes_set = 1;
+			break;
+		case ecryptfs_opt_unlink_sigs:
+			mount_crypt_stat->flags |= ECRYPTFS_UNLINK_SIGS;
+			break;
+		case ecryptfs_opt_mount_auth_tok_only:
+			mount_crypt_stat->flags |=
+				ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY;
+			break;
+		case ecryptfs_opt_check_dev_ruid:
+			*check_ruid = 1;
+			break;
+		case ecryptfs_opt_err:
+		default:
+			printk(KERN_WARNING
+			       "%s: eCryptfs: unrecognized option [%s]\n",
+			       __func__, p);
+		}
+	}
+	if (!sig_set) {
+		rc = -EINVAL;
+		ecryptfs_printk(KERN_ERR, "You must supply at least one valid "
+				"auth tok signature as a mount "
+				"parameter; see the eCryptfs README\n");
+		goto out;
+	}
+	if (!cipher_name_set) {
+		int cipher_name_len = strlen(ECRYPTFS_DEFAULT_CIPHER);
+
+		BUG_ON(cipher_name_len > ECRYPTFS_MAX_CIPHER_NAME_SIZE);
+		strcpy(mount_crypt_stat->global_default_cipher_name,
+		       ECRYPTFS_DEFAULT_CIPHER);
+	}
+	if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
+	    && !fn_cipher_name_set)
+		strcpy(mount_crypt_stat->global_default_fn_cipher_name,
+		       mount_crypt_stat->global_default_cipher_name);
+	if (!cipher_key_bytes_set)
+		mount_crypt_stat->global_default_cipher_key_size = 0;
+	if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
+	    && !fn_cipher_key_bytes_set)
+		mount_crypt_stat->global_default_fn_cipher_key_bytes =
+			mount_crypt_stat->global_default_cipher_key_size;
+
+	cipher_code = ecryptfs_code_for_cipher_string(
+		mount_crypt_stat->global_default_cipher_name,
+		mount_crypt_stat->global_default_cipher_key_size);
+	if (!cipher_code) {
+		ecryptfs_printk(KERN_ERR,
+				"eCryptfs doesn't support cipher: %s\n",
+				mount_crypt_stat->global_default_cipher_name);
+		rc = -EINVAL;
+		goto out;
+	}
+
+	mutex_lock(&key_tfm_list_mutex);
+	if (!ecryptfs_tfm_exists(mount_crypt_stat->global_default_cipher_name,
+				 NULL)) {
+		rc = ecryptfs_add_new_key_tfm(
+			NULL, mount_crypt_stat->global_default_cipher_name,
+			mount_crypt_stat->global_default_cipher_key_size);
+		if (rc) {
+			printk(KERN_ERR "Error attempting to initialize "
+			       "cipher with name = [%s] and key size = [%td]; "
+			       "rc = [%d]\n",
+			       mount_crypt_stat->global_default_cipher_name,
+			       mount_crypt_stat->global_default_cipher_key_size,
+			       rc);
+			rc = -EINVAL;
+			mutex_unlock(&key_tfm_list_mutex);
+			goto out;
+		}
+	}
+	if ((mount_crypt_stat->flags & ECRYPTFS_GLOBAL_ENCRYPT_FILENAMES)
+	    && !ecryptfs_tfm_exists(
+		    mount_crypt_stat->global_default_fn_cipher_name, NULL)) {
+		rc = ecryptfs_add_new_key_tfm(
+			NULL, mount_crypt_stat->global_default_fn_cipher_name,
+			mount_crypt_stat->global_default_fn_cipher_key_bytes);
+		if (rc) {
+			printk(KERN_ERR "Error attempting to initialize "
+			       "cipher with name = [%s] and key size = [%td]; "
+			       "rc = [%d]\n",
+			       mount_crypt_stat->global_default_fn_cipher_name,
+			       mount_crypt_stat->global_default_fn_cipher_key_bytes,
+			       rc);
+			rc = -EINVAL;
+			mutex_unlock(&key_tfm_list_mutex);
+			goto out;
+		}
+	}
+	mutex_unlock(&key_tfm_list_mutex);
+	rc = ecryptfs_init_global_auth_toks(mount_crypt_stat);
+	if (rc)
+		printk(KERN_WARNING "One or more global auth toks could not "
+		       "properly register; rc = [%d]\n", rc);
+out:
+	return rc;
+}
+
+struct kmem_cache *ecryptfs_sb_info_cache;
+static struct file_system_type ecryptfs_fs_type;
+
+/*
+ * ecryptfs_mount
+ * @fs_type: The filesystem type that the superblock should belong to
+ * @flags: The flags associated with the mount
+ * @dev_name: The path to mount over
+ * @raw_data: The options passed into the kernel
+ */
+static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags,
+			const char *dev_name, void *raw_data)
+{
+	struct super_block *s;
+	struct ecryptfs_sb_info *sbi;
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat;
+	struct ecryptfs_dentry_info *root_info;
+	const char *err = "Getting sb failed";
+	struct inode *inode;
+	struct path path;
+	uid_t check_ruid;
+	int rc;
+
+	sbi = kmem_cache_zalloc(ecryptfs_sb_info_cache, GFP_KERNEL);
+	if (!sbi) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	if (!dev_name) {
+		rc = -EINVAL;
+		err = "Device name cannot be null";
+		goto out;
+	}
+
+	rc = ecryptfs_parse_options(sbi, raw_data, &check_ruid);
+	if (rc) {
+		err = "Error parsing options";
+		goto out;
+	}
+	mount_crypt_stat = &sbi->mount_crypt_stat;
+
+	s = sget(fs_type, NULL, set_anon_super, flags, NULL);
+	if (IS_ERR(s)) {
+		rc = PTR_ERR(s);
+		goto out;
+	}
+
+	rc = super_setup_bdi(s);
+	if (rc)
+		goto out1;
+
+	ecryptfs_set_superblock_private(s, sbi);
+
+	/* ->kill_sb() will take care of sbi after that point */
+	sbi = NULL;
+	s->s_op = &ecryptfs_sops;
+	s->s_xattr = ecryptfs_xattr_handlers;
+	s->s_d_op = &ecryptfs_dops;
+
+	err = "Reading sb failed";
+	rc = kern_path(dev_name, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &path);
+	if (rc) {
+		ecryptfs_printk(KERN_WARNING, "kern_path() failed\n");
+		goto out1;
+	}
+	if (path.dentry->d_sb->s_type == &ecryptfs_fs_type) {
+		rc = -EINVAL;
+		printk(KERN_ERR "Mount on filesystem of type "
+			"eCryptfs explicitly disallowed due to "
+			"known incompatibilities\n");
+		goto out_free;
+	}
+
+	if (is_idmapped_mnt(path.mnt)) {
+		rc = -EINVAL;
+		printk(KERN_ERR "Mounting on idmapped mounts currently disallowed\n");
+		goto out_free;
+	}
+
+	if (check_ruid && !uid_eq(d_inode(path.dentry)->i_uid, current_uid())) {
+		rc = -EPERM;
+		printk(KERN_ERR "Mount of device (uid: %d) not owned by "
+		       "requested user (uid: %d)\n",
+			i_uid_read(d_inode(path.dentry)),
+			from_kuid(&init_user_ns, current_uid()));
+		goto out_free;
+	}
+
+	ecryptfs_set_superblock_lower(s, path.dentry->d_sb);
+
+	/**
+	 * Set the POSIX ACL flag based on whether they're enabled in the lower
+	 * mount.
+	 */
+	s->s_flags = flags & ~SB_POSIXACL;
+	s->s_flags |= path.dentry->d_sb->s_flags & SB_POSIXACL;
+
+	/**
+	 * Force a read-only eCryptfs mount when:
+	 *   1) The lower mount is ro
+	 *   2) The ecryptfs_encrypted_view mount option is specified
+	 */
+	if (sb_rdonly(path.dentry->d_sb) || mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
+		s->s_flags |= SB_RDONLY;
+
+	s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
+	s->s_blocksize = path.dentry->d_sb->s_blocksize;
+	s->s_magic = ECRYPTFS_SUPER_MAGIC;
+	s->s_stack_depth = path.dentry->d_sb->s_stack_depth + 1;
+
+	rc = -EINVAL;
+	if (s->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
+		pr_err("eCryptfs: maximum fs stacking depth exceeded\n");
+		goto out_free;
+	}
+
+	inode = ecryptfs_get_inode(d_inode(path.dentry), s);
+	rc = PTR_ERR(inode);
+	if (IS_ERR(inode))
+		goto out_free;
+
+	s->s_root = d_make_root(inode);
+	if (!s->s_root) {
+		rc = -ENOMEM;
+		goto out_free;
+	}
+
+	rc = -ENOMEM;
+	root_info = kmem_cache_zalloc(ecryptfs_dentry_info_cache, GFP_KERNEL);
+	if (!root_info)
+		goto out_free;
+
+	/* ->kill_sb() will take care of root_info */
+	ecryptfs_set_dentry_private(s->s_root, root_info);
+	root_info->lower_path = path;
+
+	s->s_flags |= SB_ACTIVE;
+	return dget(s->s_root);
+
+out_free:
+	path_put(&path);
+out1:
+	deactivate_locked_super(s);
+out:
+	if (sbi) {
+		ecryptfs_destroy_mount_crypt_stat(&sbi->mount_crypt_stat);
+		kmem_cache_free(ecryptfs_sb_info_cache, sbi);
+	}
+	printk(KERN_ERR "%s; rc = [%d]\n", err, rc);
+	return ERR_PTR(rc);
+}
+
+/**
+ * ecryptfs_kill_block_super
+ * @sb: The ecryptfs super block
+ *
+ * Used to bring the superblock down and free the private data.
+ */
+static void ecryptfs_kill_block_super(struct super_block *sb)
+{
+	struct ecryptfs_sb_info *sb_info = ecryptfs_superblock_to_private(sb);
+	kill_anon_super(sb);
+	if (!sb_info)
+		return;
+	ecryptfs_destroy_mount_crypt_stat(&sb_info->mount_crypt_stat);
+	kmem_cache_free(ecryptfs_sb_info_cache, sb_info);
+}
+
+static struct file_system_type ecryptfs_fs_type = {
+	.owner = THIS_MODULE,
+	.name = "ecryptfs",
+	.mount = ecryptfs_mount,
+	.kill_sb = ecryptfs_kill_block_super,
+	.fs_flags = 0
+};
+MODULE_ALIAS_FS("ecryptfs");
+
+/*
+ * inode_info_init_once
+ *
+ * Initializes the ecryptfs_inode_info_cache when it is created
+ */
+static void
+inode_info_init_once(void *vptr)
+{
+	struct ecryptfs_inode_info *ei = (struct ecryptfs_inode_info *)vptr;
+
+	inode_init_once(&ei->vfs_inode);
+}
+
+static struct ecryptfs_cache_info {
+	struct kmem_cache **cache;
+	const char *name;
+	size_t size;
+	slab_flags_t flags;
+	void (*ctor)(void *obj);
+} ecryptfs_cache_infos[] = {
+	{
+		.cache = &ecryptfs_auth_tok_list_item_cache,
+		.name = "ecryptfs_auth_tok_list_item",
+		.size = sizeof(struct ecryptfs_auth_tok_list_item),
+	},
+	{
+		.cache = &ecryptfs_file_info_cache,
+		.name = "ecryptfs_file_cache",
+		.size = sizeof(struct ecryptfs_file_info),
+	},
+	{
+		.cache = &ecryptfs_dentry_info_cache,
+		.name = "ecryptfs_dentry_info_cache",
+		.size = sizeof(struct ecryptfs_dentry_info),
+	},
+	{
+		.cache = &ecryptfs_inode_info_cache,
+		.name = "ecryptfs_inode_cache",
+		.size = sizeof(struct ecryptfs_inode_info),
+		.flags = SLAB_ACCOUNT,
+		.ctor = inode_info_init_once,
+	},
+	{
+		.cache = &ecryptfs_sb_info_cache,
+		.name = "ecryptfs_sb_cache",
+		.size = sizeof(struct ecryptfs_sb_info),
+	},
+	{
+		.cache = &ecryptfs_header_cache,
+		.name = "ecryptfs_headers",
+		.size = PAGE_SIZE,
+	},
+	{
+		.cache = &ecryptfs_xattr_cache,
+		.name = "ecryptfs_xattr_cache",
+		.size = PAGE_SIZE,
+	},
+	{
+		.cache = &ecryptfs_key_record_cache,
+		.name = "ecryptfs_key_record_cache",
+		.size = sizeof(struct ecryptfs_key_record),
+	},
+	{
+		.cache = &ecryptfs_key_sig_cache,
+		.name = "ecryptfs_key_sig_cache",
+		.size = sizeof(struct ecryptfs_key_sig),
+	},
+	{
+		.cache = &ecryptfs_global_auth_tok_cache,
+		.name = "ecryptfs_global_auth_tok_cache",
+		.size = sizeof(struct ecryptfs_global_auth_tok),
+	},
+	{
+		.cache = &ecryptfs_key_tfm_cache,
+		.name = "ecryptfs_key_tfm_cache",
+		.size = sizeof(struct ecryptfs_key_tfm),
+	},
+};
+
+static void ecryptfs_free_kmem_caches(void)
+{
+	int i;
+
+	/*
+	 * Make sure all delayed rcu free inodes are flushed before we
+	 * destroy cache.
+	 */
+	rcu_barrier();
+
+	for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
+		struct ecryptfs_cache_info *info;
+
+		info = &ecryptfs_cache_infos[i];
+		kmem_cache_destroy(*(info->cache));
+	}
+}
+
+/**
+ * ecryptfs_init_kmem_caches
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int ecryptfs_init_kmem_caches(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(ecryptfs_cache_infos); i++) {
+		struct ecryptfs_cache_info *info;
+
+		info = &ecryptfs_cache_infos[i];
+		*(info->cache) = kmem_cache_create(info->name, info->size, 0,
+				SLAB_HWCACHE_ALIGN | info->flags, info->ctor);
+		if (!*(info->cache)) {
+			ecryptfs_free_kmem_caches();
+			ecryptfs_printk(KERN_WARNING, "%s: "
+					"kmem_cache_create failed\n",
+					info->name);
+			return -ENOMEM;
+		}
+	}
+	return 0;
+}
+
+static struct kobject *ecryptfs_kobj;
+
+static ssize_t version_show(struct kobject *kobj,
+			    struct kobj_attribute *attr, char *buff)
+{
+	return snprintf(buff, PAGE_SIZE, "%d\n", ECRYPTFS_VERSIONING_MASK);
+}
+
+static struct kobj_attribute version_attr = __ATTR_RO(version);
+
+static struct attribute *attributes[] = {
+	&version_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group attr_group = {
+	.attrs = attributes,
+};
+
+static int do_sysfs_registration(void)
+{
+	int rc;
+
+	ecryptfs_kobj = kobject_create_and_add("ecryptfs", fs_kobj);
+	if (!ecryptfs_kobj) {
+		printk(KERN_ERR "Unable to create ecryptfs kset\n");
+		rc = -ENOMEM;
+		goto out;
+	}
+	rc = sysfs_create_group(ecryptfs_kobj, &attr_group);
+	if (rc) {
+		printk(KERN_ERR
+		       "Unable to create ecryptfs version attributes\n");
+		kobject_put(ecryptfs_kobj);
+	}
+out:
+	return rc;
+}
+
+static void do_sysfs_unregistration(void)
+{
+	sysfs_remove_group(ecryptfs_kobj, &attr_group);
+	kobject_put(ecryptfs_kobj);
+}
+
+static int __init ecryptfs_init(void)
+{
+	int rc;
+
+	if (ECRYPTFS_DEFAULT_EXTENT_SIZE > PAGE_SIZE) {
+		rc = -EINVAL;
+		ecryptfs_printk(KERN_ERR, "The eCryptfs extent size is "
+				"larger than the host's page size, and so "
+				"eCryptfs cannot run on this system. The "
+				"default eCryptfs extent size is [%u] bytes; "
+				"the page size is [%lu] bytes.\n",
+				ECRYPTFS_DEFAULT_EXTENT_SIZE,
+				(unsigned long)PAGE_SIZE);
+		goto out;
+	}
+	rc = ecryptfs_init_kmem_caches();
+	if (rc) {
+		printk(KERN_ERR
+		       "Failed to allocate one or more kmem_cache objects\n");
+		goto out;
+	}
+	rc = do_sysfs_registration();
+	if (rc) {
+		printk(KERN_ERR "sysfs registration failed\n");
+		goto out_free_kmem_caches;
+	}
+	rc = ecryptfs_init_kthread();
+	if (rc) {
+		printk(KERN_ERR "%s: kthread initialization failed; "
+		       "rc = [%d]\n", __func__, rc);
+		goto out_do_sysfs_unregistration;
+	}
+	rc = ecryptfs_init_messaging();
+	if (rc) {
+		printk(KERN_ERR "Failure occurred while attempting to "
+				"initialize the communications channel to "
+				"ecryptfsd\n");
+		goto out_destroy_kthread;
+	}
+	rc = ecryptfs_init_crypto();
+	if (rc) {
+		printk(KERN_ERR "Failure whilst attempting to init crypto; "
+		       "rc = [%d]\n", rc);
+		goto out_release_messaging;
+	}
+	rc = register_filesystem(&ecryptfs_fs_type);
+	if (rc) {
+		printk(KERN_ERR "Failed to register filesystem\n");
+		goto out_destroy_crypto;
+	}
+	if (ecryptfs_verbosity > 0)
+		printk(KERN_CRIT "eCryptfs verbosity set to %d. Secret values "
+			"will be written to the syslog!\n", ecryptfs_verbosity);
+
+	goto out;
+out_destroy_crypto:
+	ecryptfs_destroy_crypto();
+out_release_messaging:
+	ecryptfs_release_messaging();
+out_destroy_kthread:
+	ecryptfs_destroy_kthread();
+out_do_sysfs_unregistration:
+	do_sysfs_unregistration();
+out_free_kmem_caches:
+	ecryptfs_free_kmem_caches();
+out:
+	return rc;
+}
+
+static void __exit ecryptfs_exit(void)
+{
+	int rc;
+
+	rc = ecryptfs_destroy_crypto();
+	if (rc)
+		printk(KERN_ERR "Failure whilst attempting to destroy crypto; "
+		       "rc = [%d]\n", rc);
+	ecryptfs_release_messaging();
+	ecryptfs_destroy_kthread();
+	do_sysfs_unregistration();
+	unregister_filesystem(&ecryptfs_fs_type);
+	ecryptfs_free_kmem_caches();
+}
+
+MODULE_AUTHOR("Michael A. Halcrow <mhalcrow@us.ibm.com>");
+MODULE_DESCRIPTION("eCryptfs");
+
+MODULE_LICENSE("GPL");
+
+module_init(ecryptfs_init)
+module_exit(ecryptfs_exit)
diff --git a/fs/ecryptfs/messaging.c b/fs/ecryptfs/messaging.c
new file mode 100644
index 000000000..6318f3500
--- /dev/null
+++ b/fs/ecryptfs/messaging.c
@@ -0,0 +1,451 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 2004-2008 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
+ *		Tyler Hicks <code@tyhicks.com>
+ */
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/user_namespace.h>
+#include <linux/nsproxy.h>
+#include "ecryptfs_kernel.h"
+
+static LIST_HEAD(ecryptfs_msg_ctx_free_list);
+static LIST_HEAD(ecryptfs_msg_ctx_alloc_list);
+static DEFINE_MUTEX(ecryptfs_msg_ctx_lists_mux);
+
+static struct hlist_head *ecryptfs_daemon_hash;
+DEFINE_MUTEX(ecryptfs_daemon_hash_mux);
+static int ecryptfs_hash_bits;
+#define ecryptfs_current_euid_hash(uid) \
+	hash_long((unsigned long)from_kuid(&init_user_ns, current_euid()), ecryptfs_hash_bits)
+
+static u32 ecryptfs_msg_counter;
+static struct ecryptfs_msg_ctx *ecryptfs_msg_ctx_arr;
+
+/**
+ * ecryptfs_acquire_free_msg_ctx
+ * @msg_ctx: The context that was acquired from the free list
+ *
+ * Acquires a context element from the free list and locks the mutex
+ * on the context.  Sets the msg_ctx task to current.  Returns zero on
+ * success; non-zero on error or upon failure to acquire a free
+ * context element.  Must be called with ecryptfs_msg_ctx_lists_mux
+ * held.
+ */
+static int ecryptfs_acquire_free_msg_ctx(struct ecryptfs_msg_ctx **msg_ctx)
+{
+	struct list_head *p;
+	int rc;
+
+	if (list_empty(&ecryptfs_msg_ctx_free_list)) {
+		printk(KERN_WARNING "%s: The eCryptfs free "
+		       "context list is empty.  It may be helpful to "
+		       "specify the ecryptfs_message_buf_len "
+		       "parameter to be greater than the current "
+		       "value of [%d]\n", __func__, ecryptfs_message_buf_len);
+		rc = -ENOMEM;
+		goto out;
+	}
+	list_for_each(p, &ecryptfs_msg_ctx_free_list) {
+		*msg_ctx = list_entry(p, struct ecryptfs_msg_ctx, node);
+		if (mutex_trylock(&(*msg_ctx)->mux)) {
+			(*msg_ctx)->task = current;
+			rc = 0;
+			goto out;
+		}
+	}
+	rc = -ENOMEM;
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_msg_ctx_free_to_alloc
+ * @msg_ctx: The context to move from the free list to the alloc list
+ *
+ * Must be called with ecryptfs_msg_ctx_lists_mux held.
+ */
+static void ecryptfs_msg_ctx_free_to_alloc(struct ecryptfs_msg_ctx *msg_ctx)
+{
+	list_move(&msg_ctx->node, &ecryptfs_msg_ctx_alloc_list);
+	msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_PENDING;
+	msg_ctx->counter = ++ecryptfs_msg_counter;
+}
+
+/**
+ * ecryptfs_msg_ctx_alloc_to_free
+ * @msg_ctx: The context to move from the alloc list to the free list
+ *
+ * Must be called with ecryptfs_msg_ctx_lists_mux held.
+ */
+void ecryptfs_msg_ctx_alloc_to_free(struct ecryptfs_msg_ctx *msg_ctx)
+{
+	list_move(&(msg_ctx->node), &ecryptfs_msg_ctx_free_list);
+	kfree(msg_ctx->msg);
+	msg_ctx->msg = NULL;
+	msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_FREE;
+}
+
+/**
+ * ecryptfs_find_daemon_by_euid
+ * @daemon: If return value is zero, points to the desired daemon pointer
+ *
+ * Must be called with ecryptfs_daemon_hash_mux held.
+ *
+ * Search the hash list for the current effective user id.
+ *
+ * Returns zero if the user id exists in the list; non-zero otherwise.
+ */
+int ecryptfs_find_daemon_by_euid(struct ecryptfs_daemon **daemon)
+{
+	int rc;
+
+	hlist_for_each_entry(*daemon,
+			    &ecryptfs_daemon_hash[ecryptfs_current_euid_hash()],
+			    euid_chain) {
+		if (uid_eq((*daemon)->file->f_cred->euid, current_euid())) {
+			rc = 0;
+			goto out;
+		}
+	}
+	rc = -EINVAL;
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_spawn_daemon - Create and initialize a new daemon struct
+ * @daemon: Pointer to set to newly allocated daemon struct
+ * @file: File used when opening /dev/ecryptfs
+ *
+ * Must be called ceremoniously while in possession of
+ * ecryptfs_sacred_daemon_hash_mux
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int
+ecryptfs_spawn_daemon(struct ecryptfs_daemon **daemon, struct file *file)
+{
+	int rc = 0;
+
+	(*daemon) = kzalloc(sizeof(**daemon), GFP_KERNEL);
+	if (!(*daemon)) {
+		rc = -ENOMEM;
+		goto out;
+	}
+	(*daemon)->file = file;
+	mutex_init(&(*daemon)->mux);
+	INIT_LIST_HEAD(&(*daemon)->msg_ctx_out_queue);
+	init_waitqueue_head(&(*daemon)->wait);
+	(*daemon)->num_queued_msg_ctx = 0;
+	hlist_add_head(&(*daemon)->euid_chain,
+		       &ecryptfs_daemon_hash[ecryptfs_current_euid_hash()]);
+out:
+	return rc;
+}
+
+/*
+ * ecryptfs_exorcise_daemon - Destroy the daemon struct
+ *
+ * Must be called ceremoniously while in possession of
+ * ecryptfs_daemon_hash_mux and the daemon's own mux.
+ */
+int ecryptfs_exorcise_daemon(struct ecryptfs_daemon *daemon)
+{
+	struct ecryptfs_msg_ctx *msg_ctx, *msg_ctx_tmp;
+	int rc = 0;
+
+	mutex_lock(&daemon->mux);
+	if ((daemon->flags & ECRYPTFS_DAEMON_IN_READ)
+	    || (daemon->flags & ECRYPTFS_DAEMON_IN_POLL)) {
+		rc = -EBUSY;
+		mutex_unlock(&daemon->mux);
+		goto out;
+	}
+	list_for_each_entry_safe(msg_ctx, msg_ctx_tmp,
+				 &daemon->msg_ctx_out_queue, daemon_out_list) {
+		list_del(&msg_ctx->daemon_out_list);
+		daemon->num_queued_msg_ctx--;
+		printk(KERN_WARNING "%s: Warning: dropping message that is in "
+		       "the out queue of a dying daemon\n", __func__);
+		ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
+	}
+	hlist_del(&daemon->euid_chain);
+	mutex_unlock(&daemon->mux);
+	kfree_sensitive(daemon);
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_process_response
+ * @daemon: eCryptfs daemon object
+ * @msg: The ecryptfs message received; the caller should sanity check
+ *       msg->data_len and free the memory
+ * @seq: The sequence number of the message; must match the sequence
+ *       number for the existing message context waiting for this
+ *       response
+ *
+ * Processes a response message after sending an operation request to
+ * userspace. Some other process is awaiting this response. Before
+ * sending out its first communications, the other process allocated a
+ * msg_ctx from the ecryptfs_msg_ctx_arr at a particular index. The
+ * response message contains this index so that we can copy over the
+ * response message into the msg_ctx that the process holds a
+ * reference to. The other process is going to wake up, check to see
+ * that msg_ctx->state == ECRYPTFS_MSG_CTX_STATE_DONE, and then
+ * proceed to read off and process the response message. Returns zero
+ * upon delivery to desired context element; non-zero upon delivery
+ * failure or error.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int ecryptfs_process_response(struct ecryptfs_daemon *daemon,
+			      struct ecryptfs_message *msg, u32 seq)
+{
+	struct ecryptfs_msg_ctx *msg_ctx;
+	size_t msg_size;
+	int rc;
+
+	if (msg->index >= ecryptfs_message_buf_len) {
+		rc = -EINVAL;
+		printk(KERN_ERR "%s: Attempt to reference "
+		       "context buffer at index [%d]; maximum "
+		       "allowable is [%d]\n", __func__, msg->index,
+		       (ecryptfs_message_buf_len - 1));
+		goto out;
+	}
+	msg_ctx = &ecryptfs_msg_ctx_arr[msg->index];
+	mutex_lock(&msg_ctx->mux);
+	if (msg_ctx->state != ECRYPTFS_MSG_CTX_STATE_PENDING) {
+		rc = -EINVAL;
+		printk(KERN_WARNING "%s: Desired context element is not "
+		       "pending a response\n", __func__);
+		goto unlock;
+	} else if (msg_ctx->counter != seq) {
+		rc = -EINVAL;
+		printk(KERN_WARNING "%s: Invalid message sequence; "
+		       "expected [%d]; received [%d]\n", __func__,
+		       msg_ctx->counter, seq);
+		goto unlock;
+	}
+	msg_size = (sizeof(*msg) + msg->data_len);
+	msg_ctx->msg = kmemdup(msg, msg_size, GFP_KERNEL);
+	if (!msg_ctx->msg) {
+		rc = -ENOMEM;
+		goto unlock;
+	}
+	msg_ctx->state = ECRYPTFS_MSG_CTX_STATE_DONE;
+	wake_up_process(msg_ctx->task);
+	rc = 0;
+unlock:
+	mutex_unlock(&msg_ctx->mux);
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_send_message_locked
+ * @data: The data to send
+ * @data_len: The length of data
+ * @msg_type: Type of message
+ * @msg_ctx: The message context allocated for the send
+ *
+ * Must be called with ecryptfs_daemon_hash_mux held.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int
+ecryptfs_send_message_locked(char *data, int data_len, u8 msg_type,
+			     struct ecryptfs_msg_ctx **msg_ctx)
+{
+	struct ecryptfs_daemon *daemon;
+	int rc;
+
+	rc = ecryptfs_find_daemon_by_euid(&daemon);
+	if (rc) {
+		rc = -ENOTCONN;
+		goto out;
+	}
+	mutex_lock(&ecryptfs_msg_ctx_lists_mux);
+	rc = ecryptfs_acquire_free_msg_ctx(msg_ctx);
+	if (rc) {
+		mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
+		printk(KERN_WARNING "%s: Could not claim a free "
+		       "context element\n", __func__);
+		goto out;
+	}
+	ecryptfs_msg_ctx_free_to_alloc(*msg_ctx);
+	mutex_unlock(&(*msg_ctx)->mux);
+	mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
+	rc = ecryptfs_send_miscdev(data, data_len, *msg_ctx, msg_type, 0,
+				   daemon);
+	if (rc)
+		printk(KERN_ERR "%s: Error attempting to send message to "
+		       "userspace daemon; rc = [%d]\n", __func__, rc);
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_send_message
+ * @data: The data to send
+ * @data_len: The length of data
+ * @msg_ctx: The message context allocated for the send
+ *
+ * Grabs ecryptfs_daemon_hash_mux.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int ecryptfs_send_message(char *data, int data_len,
+			  struct ecryptfs_msg_ctx **msg_ctx)
+{
+	int rc;
+
+	mutex_lock(&ecryptfs_daemon_hash_mux);
+	rc = ecryptfs_send_message_locked(data, data_len, ECRYPTFS_MSG_REQUEST,
+					  msg_ctx);
+	mutex_unlock(&ecryptfs_daemon_hash_mux);
+	return rc;
+}
+
+/**
+ * ecryptfs_wait_for_response
+ * @msg_ctx: The context that was assigned when sending a message
+ * @msg: The incoming message from userspace; not set if rc != 0
+ *
+ * Sleeps until awaken by ecryptfs_receive_message or until the amount
+ * of time exceeds ecryptfs_message_wait_timeout.  If zero is
+ * returned, msg will point to a valid message from userspace; a
+ * non-zero value is returned upon failure to receive a message or an
+ * error occurs. Callee must free @msg on success.
+ */
+int ecryptfs_wait_for_response(struct ecryptfs_msg_ctx *msg_ctx,
+			       struct ecryptfs_message **msg)
+{
+	signed long timeout = ecryptfs_message_wait_timeout * HZ;
+	int rc = 0;
+
+sleep:
+	timeout = schedule_timeout_interruptible(timeout);
+	mutex_lock(&ecryptfs_msg_ctx_lists_mux);
+	mutex_lock(&msg_ctx->mux);
+	if (msg_ctx->state != ECRYPTFS_MSG_CTX_STATE_DONE) {
+		if (timeout) {
+			mutex_unlock(&msg_ctx->mux);
+			mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
+			goto sleep;
+		}
+		rc = -ENOMSG;
+	} else {
+		*msg = msg_ctx->msg;
+		msg_ctx->msg = NULL;
+	}
+	ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
+	mutex_unlock(&msg_ctx->mux);
+	mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
+	return rc;
+}
+
+int __init ecryptfs_init_messaging(void)
+{
+	int i;
+	int rc = 0;
+
+	if (ecryptfs_number_of_users > ECRYPTFS_MAX_NUM_USERS) {
+		ecryptfs_number_of_users = ECRYPTFS_MAX_NUM_USERS;
+		printk(KERN_WARNING "%s: Specified number of users is "
+		       "too large, defaulting to [%d] users\n", __func__,
+		       ecryptfs_number_of_users);
+	}
+	mutex_lock(&ecryptfs_daemon_hash_mux);
+	ecryptfs_hash_bits = 1;
+	while (ecryptfs_number_of_users >> ecryptfs_hash_bits)
+		ecryptfs_hash_bits++;
+	ecryptfs_daemon_hash = kmalloc((sizeof(struct hlist_head)
+					* (1 << ecryptfs_hash_bits)),
+				       GFP_KERNEL);
+	if (!ecryptfs_daemon_hash) {
+		rc = -ENOMEM;
+		mutex_unlock(&ecryptfs_daemon_hash_mux);
+		goto out;
+	}
+	for (i = 0; i < (1 << ecryptfs_hash_bits); i++)
+		INIT_HLIST_HEAD(&ecryptfs_daemon_hash[i]);
+	mutex_unlock(&ecryptfs_daemon_hash_mux);
+	ecryptfs_msg_ctx_arr = kmalloc((sizeof(struct ecryptfs_msg_ctx)
+					* ecryptfs_message_buf_len),
+				       GFP_KERNEL);
+	if (!ecryptfs_msg_ctx_arr) {
+		kfree(ecryptfs_daemon_hash);
+		rc = -ENOMEM;
+		goto out;
+	}
+	mutex_lock(&ecryptfs_msg_ctx_lists_mux);
+	ecryptfs_msg_counter = 0;
+	for (i = 0; i < ecryptfs_message_buf_len; i++) {
+		INIT_LIST_HEAD(&ecryptfs_msg_ctx_arr[i].node);
+		INIT_LIST_HEAD(&ecryptfs_msg_ctx_arr[i].daemon_out_list);
+		mutex_init(&ecryptfs_msg_ctx_arr[i].mux);
+		mutex_lock(&ecryptfs_msg_ctx_arr[i].mux);
+		ecryptfs_msg_ctx_arr[i].index = i;
+		ecryptfs_msg_ctx_arr[i].state = ECRYPTFS_MSG_CTX_STATE_FREE;
+		ecryptfs_msg_ctx_arr[i].counter = 0;
+		ecryptfs_msg_ctx_arr[i].task = NULL;
+		ecryptfs_msg_ctx_arr[i].msg = NULL;
+		list_add_tail(&ecryptfs_msg_ctx_arr[i].node,
+			      &ecryptfs_msg_ctx_free_list);
+		mutex_unlock(&ecryptfs_msg_ctx_arr[i].mux);
+	}
+	mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
+	rc = ecryptfs_init_ecryptfs_miscdev();
+	if (rc)
+		ecryptfs_release_messaging();
+out:
+	return rc;
+}
+
+void ecryptfs_release_messaging(void)
+{
+	if (ecryptfs_msg_ctx_arr) {
+		int i;
+
+		mutex_lock(&ecryptfs_msg_ctx_lists_mux);
+		for (i = 0; i < ecryptfs_message_buf_len; i++) {
+			mutex_lock(&ecryptfs_msg_ctx_arr[i].mux);
+			kfree(ecryptfs_msg_ctx_arr[i].msg);
+			mutex_unlock(&ecryptfs_msg_ctx_arr[i].mux);
+		}
+		kfree(ecryptfs_msg_ctx_arr);
+		mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
+	}
+	if (ecryptfs_daemon_hash) {
+		struct ecryptfs_daemon *daemon;
+		struct hlist_node *n;
+		int i;
+
+		mutex_lock(&ecryptfs_daemon_hash_mux);
+		for (i = 0; i < (1 << ecryptfs_hash_bits); i++) {
+			int rc;
+
+			hlist_for_each_entry_safe(daemon, n,
+						  &ecryptfs_daemon_hash[i],
+						  euid_chain) {
+				rc = ecryptfs_exorcise_daemon(daemon);
+				if (rc)
+					printk(KERN_ERR "%s: Error whilst "
+					       "attempting to destroy daemon; "
+					       "rc = [%d]. Dazed and confused, "
+					       "but trying to continue.\n",
+					       __func__, rc);
+			}
+		}
+		kfree(ecryptfs_daemon_hash);
+		mutex_unlock(&ecryptfs_daemon_hash_mux);
+	}
+	ecryptfs_destroy_ecryptfs_miscdev();
+	return;
+}
diff --git a/fs/ecryptfs/miscdev.c b/fs/ecryptfs/miscdev.c
new file mode 100644
index 000000000..4e62c3cef
--- /dev/null
+++ b/fs/ecryptfs/miscdev.c
@@ -0,0 +1,495 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 2008 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mhalcrow@us.ibm.com>
+ */
+
+#include <linux/fs.h>
+#include <linux/hash.h>
+#include <linux/random.h>
+#include <linux/miscdevice.h>
+#include <linux/poll.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+#include <linux/module.h>
+#include "ecryptfs_kernel.h"
+
+static atomic_t ecryptfs_num_miscdev_opens;
+
+/**
+ * ecryptfs_miscdev_poll
+ * @file: dev file
+ * @pt: dev poll table (ignored)
+ *
+ * Returns the poll mask
+ */
+static __poll_t
+ecryptfs_miscdev_poll(struct file *file, poll_table *pt)
+{
+	struct ecryptfs_daemon *daemon = file->private_data;
+	__poll_t mask = 0;
+
+	mutex_lock(&daemon->mux);
+	if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
+		printk(KERN_WARNING "%s: Attempt to poll on zombified "
+		       "daemon\n", __func__);
+		goto out_unlock_daemon;
+	}
+	if (daemon->flags & ECRYPTFS_DAEMON_IN_READ)
+		goto out_unlock_daemon;
+	if (daemon->flags & ECRYPTFS_DAEMON_IN_POLL)
+		goto out_unlock_daemon;
+	daemon->flags |= ECRYPTFS_DAEMON_IN_POLL;
+	mutex_unlock(&daemon->mux);
+	poll_wait(file, &daemon->wait, pt);
+	mutex_lock(&daemon->mux);
+	if (!list_empty(&daemon->msg_ctx_out_queue))
+		mask |= EPOLLIN | EPOLLRDNORM;
+out_unlock_daemon:
+	daemon->flags &= ~ECRYPTFS_DAEMON_IN_POLL;
+	mutex_unlock(&daemon->mux);
+	return mask;
+}
+
+/**
+ * ecryptfs_miscdev_open
+ * @inode: inode of miscdev handle (ignored)
+ * @file: file for miscdev handle
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int
+ecryptfs_miscdev_open(struct inode *inode, struct file *file)
+{
+	struct ecryptfs_daemon *daemon = NULL;
+	int rc;
+
+	mutex_lock(&ecryptfs_daemon_hash_mux);
+	rc = ecryptfs_find_daemon_by_euid(&daemon);
+	if (!rc) {
+		rc = -EINVAL;
+		goto out_unlock_daemon_list;
+	}
+	rc = ecryptfs_spawn_daemon(&daemon, file);
+	if (rc) {
+		printk(KERN_ERR "%s: Error attempting to spawn daemon; "
+		       "rc = [%d]\n", __func__, rc);
+		goto out_unlock_daemon_list;
+	}
+	mutex_lock(&daemon->mux);
+	if (daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN) {
+		rc = -EBUSY;
+		goto out_unlock_daemon;
+	}
+	daemon->flags |= ECRYPTFS_DAEMON_MISCDEV_OPEN;
+	file->private_data = daemon;
+	atomic_inc(&ecryptfs_num_miscdev_opens);
+out_unlock_daemon:
+	mutex_unlock(&daemon->mux);
+out_unlock_daemon_list:
+	mutex_unlock(&ecryptfs_daemon_hash_mux);
+	return rc;
+}
+
+/**
+ * ecryptfs_miscdev_release
+ * @inode: inode of fs/ecryptfs/euid handle (ignored)
+ * @file: file for fs/ecryptfs/euid handle
+ *
+ * This keeps the daemon registered until the daemon sends another
+ * ioctl to fs/ecryptfs/ctl or until the kernel module unregisters.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int
+ecryptfs_miscdev_release(struct inode *inode, struct file *file)
+{
+	struct ecryptfs_daemon *daemon = file->private_data;
+	int rc;
+
+	mutex_lock(&daemon->mux);
+	BUG_ON(!(daemon->flags & ECRYPTFS_DAEMON_MISCDEV_OPEN));
+	daemon->flags &= ~ECRYPTFS_DAEMON_MISCDEV_OPEN;
+	atomic_dec(&ecryptfs_num_miscdev_opens);
+	mutex_unlock(&daemon->mux);
+
+	mutex_lock(&ecryptfs_daemon_hash_mux);
+	rc = ecryptfs_exorcise_daemon(daemon);
+	mutex_unlock(&ecryptfs_daemon_hash_mux);
+	if (rc) {
+		printk(KERN_CRIT "%s: Fatal error whilst attempting to "
+		       "shut down daemon; rc = [%d]. Please report this "
+		       "bug.\n", __func__, rc);
+		BUG();
+	}
+	return rc;
+}
+
+/**
+ * ecryptfs_send_miscdev
+ * @data: Data to send to daemon; may be NULL
+ * @data_size: Amount of data to send to daemon
+ * @msg_ctx: Message context, which is used to handle the reply. If
+ *           this is NULL, then we do not expect a reply.
+ * @msg_type: Type of message
+ * @msg_flags: Flags for message
+ * @daemon: eCryptfs daemon object
+ *
+ * Add msg_ctx to queue and then, if it exists, notify the blocked
+ * miscdevess about the data being available. Must be called with
+ * ecryptfs_daemon_hash_mux held.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int ecryptfs_send_miscdev(char *data, size_t data_size,
+			  struct ecryptfs_msg_ctx *msg_ctx, u8 msg_type,
+			  u16 msg_flags, struct ecryptfs_daemon *daemon)
+{
+	struct ecryptfs_message *msg;
+
+	msg = kmalloc((sizeof(*msg) + data_size), GFP_KERNEL);
+	if (!msg)
+		return -ENOMEM;
+
+	mutex_lock(&msg_ctx->mux);
+	msg_ctx->msg = msg;
+	msg_ctx->msg->index = msg_ctx->index;
+	msg_ctx->msg->data_len = data_size;
+	msg_ctx->type = msg_type;
+	memcpy(msg_ctx->msg->data, data, data_size);
+	msg_ctx->msg_size = (sizeof(*msg_ctx->msg) + data_size);
+	list_add_tail(&msg_ctx->daemon_out_list, &daemon->msg_ctx_out_queue);
+	mutex_unlock(&msg_ctx->mux);
+
+	mutex_lock(&daemon->mux);
+	daemon->num_queued_msg_ctx++;
+	wake_up_interruptible(&daemon->wait);
+	mutex_unlock(&daemon->mux);
+
+	return 0;
+}
+
+/*
+ * miscdevfs packet format:
+ *  Octet 0: Type
+ *  Octets 1-4: network byte order msg_ctx->counter
+ *  Octets 5-N0: Size of struct ecryptfs_message to follow
+ *  Octets N0-N1: struct ecryptfs_message (including data)
+ *
+ *  Octets 5-N1 not written if the packet type does not include a message
+ */
+#define PKT_TYPE_SIZE		1
+#define PKT_CTR_SIZE		4
+#define MIN_NON_MSG_PKT_SIZE	(PKT_TYPE_SIZE + PKT_CTR_SIZE)
+#define MIN_MSG_PKT_SIZE	(PKT_TYPE_SIZE + PKT_CTR_SIZE \
+				 + ECRYPTFS_MIN_PKT_LEN_SIZE)
+/* 4 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES comes from tag 65 packet format */
+#define MAX_MSG_PKT_SIZE	(PKT_TYPE_SIZE + PKT_CTR_SIZE \
+				 + ECRYPTFS_MAX_PKT_LEN_SIZE \
+				 + sizeof(struct ecryptfs_message) \
+				 + 4 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES)
+#define PKT_TYPE_OFFSET		0
+#define PKT_CTR_OFFSET		PKT_TYPE_SIZE
+#define PKT_LEN_OFFSET		(PKT_TYPE_SIZE + PKT_CTR_SIZE)
+
+/**
+ * ecryptfs_miscdev_read - format and send message from queue
+ * @file: miscdevfs handle
+ * @buf: User buffer into which to copy the next message on the daemon queue
+ * @count: Amount of space available in @buf
+ * @ppos: Offset in file (ignored)
+ *
+ * Pulls the most recent message from the daemon queue, formats it for
+ * being sent via a miscdevfs handle, and copies it into @buf
+ *
+ * Returns the number of bytes copied into the user buffer
+ */
+static ssize_t
+ecryptfs_miscdev_read(struct file *file, char __user *buf, size_t count,
+		      loff_t *ppos)
+{
+	struct ecryptfs_daemon *daemon = file->private_data;
+	struct ecryptfs_msg_ctx *msg_ctx;
+	size_t packet_length_size;
+	char packet_length[ECRYPTFS_MAX_PKT_LEN_SIZE];
+	size_t i;
+	size_t total_length;
+	int rc;
+
+	mutex_lock(&daemon->mux);
+	if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
+		rc = 0;
+		printk(KERN_WARNING "%s: Attempt to read from zombified "
+		       "daemon\n", __func__);
+		goto out_unlock_daemon;
+	}
+	if (daemon->flags & ECRYPTFS_DAEMON_IN_READ) {
+		rc = 0;
+		goto out_unlock_daemon;
+	}
+	/* This daemon will not go away so long as this flag is set */
+	daemon->flags |= ECRYPTFS_DAEMON_IN_READ;
+check_list:
+	if (list_empty(&daemon->msg_ctx_out_queue)) {
+		mutex_unlock(&daemon->mux);
+		rc = wait_event_interruptible(
+			daemon->wait, !list_empty(&daemon->msg_ctx_out_queue));
+		mutex_lock(&daemon->mux);
+		if (rc < 0) {
+			rc = 0;
+			goto out_unlock_daemon;
+		}
+	}
+	if (daemon->flags & ECRYPTFS_DAEMON_ZOMBIE) {
+		rc = 0;
+		goto out_unlock_daemon;
+	}
+	if (list_empty(&daemon->msg_ctx_out_queue)) {
+		/* Something else jumped in since the
+		 * wait_event_interruptable() and removed the
+		 * message from the queue; try again */
+		goto check_list;
+	}
+	msg_ctx = list_first_entry(&daemon->msg_ctx_out_queue,
+				   struct ecryptfs_msg_ctx, daemon_out_list);
+	BUG_ON(!msg_ctx);
+	mutex_lock(&msg_ctx->mux);
+	if (msg_ctx->msg) {
+		rc = ecryptfs_write_packet_length(packet_length,
+						  msg_ctx->msg_size,
+						  &packet_length_size);
+		if (rc) {
+			rc = 0;
+			printk(KERN_WARNING "%s: Error writing packet length; "
+			       "rc = [%d]\n", __func__, rc);
+			goto out_unlock_msg_ctx;
+		}
+	} else {
+		packet_length_size = 0;
+		msg_ctx->msg_size = 0;
+	}
+	total_length = (PKT_TYPE_SIZE + PKT_CTR_SIZE + packet_length_size
+			+ msg_ctx->msg_size);
+	if (count < total_length) {
+		rc = 0;
+		printk(KERN_WARNING "%s: Only given user buffer of "
+		       "size [%zd], but we need [%zd] to read the "
+		       "pending message\n", __func__, count, total_length);
+		goto out_unlock_msg_ctx;
+	}
+	rc = -EFAULT;
+	if (put_user(msg_ctx->type, buf))
+		goto out_unlock_msg_ctx;
+	if (put_user(cpu_to_be32(msg_ctx->counter),
+		     (__be32 __user *)(&buf[PKT_CTR_OFFSET])))
+		goto out_unlock_msg_ctx;
+	i = PKT_TYPE_SIZE + PKT_CTR_SIZE;
+	if (msg_ctx->msg) {
+		if (copy_to_user(&buf[i], packet_length, packet_length_size))
+			goto out_unlock_msg_ctx;
+		i += packet_length_size;
+		if (copy_to_user(&buf[i], msg_ctx->msg, msg_ctx->msg_size))
+			goto out_unlock_msg_ctx;
+		i += msg_ctx->msg_size;
+	}
+	rc = i;
+	list_del(&msg_ctx->daemon_out_list);
+	kfree(msg_ctx->msg);
+	msg_ctx->msg = NULL;
+	/* We do not expect a reply from the userspace daemon for any
+	 * message type other than ECRYPTFS_MSG_REQUEST */
+	if (msg_ctx->type != ECRYPTFS_MSG_REQUEST)
+		ecryptfs_msg_ctx_alloc_to_free(msg_ctx);
+out_unlock_msg_ctx:
+	mutex_unlock(&msg_ctx->mux);
+out_unlock_daemon:
+	daemon->flags &= ~ECRYPTFS_DAEMON_IN_READ;
+	mutex_unlock(&daemon->mux);
+	return rc;
+}
+
+/**
+ * ecryptfs_miscdev_response - miscdevess response to message previously sent to daemon
+ * @daemon: eCryptfs daemon object
+ * @data: Bytes comprising struct ecryptfs_message
+ * @data_size: sizeof(struct ecryptfs_message) + data len
+ * @seq: Sequence number for miscdev response packet
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int ecryptfs_miscdev_response(struct ecryptfs_daemon *daemon, char *data,
+				     size_t data_size, u32 seq)
+{
+	struct ecryptfs_message *msg = (struct ecryptfs_message *)data;
+	int rc;
+
+	if ((sizeof(*msg) + msg->data_len) != data_size) {
+		printk(KERN_WARNING "%s: (sizeof(*msg) + msg->data_len) = "
+		       "[%zd]; data_size = [%zd]. Invalid packet.\n", __func__,
+		       (sizeof(*msg) + msg->data_len), data_size);
+		rc = -EINVAL;
+		goto out;
+	}
+	rc = ecryptfs_process_response(daemon, msg, seq);
+	if (rc)
+		printk(KERN_ERR
+		       "Error processing response message; rc = [%d]\n", rc);
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_miscdev_write - handle write to daemon miscdev handle
+ * @file: File for misc dev handle
+ * @buf: Buffer containing user data
+ * @count: Amount of data in @buf
+ * @ppos: Pointer to offset in file (ignored)
+ *
+ * Returns the number of bytes read from @buf
+ */
+static ssize_t
+ecryptfs_miscdev_write(struct file *file, const char __user *buf,
+		       size_t count, loff_t *ppos)
+{
+	__be32 counter_nbo;
+	u32 seq;
+	size_t packet_size, packet_size_length;
+	char *data;
+	unsigned char packet_size_peek[ECRYPTFS_MAX_PKT_LEN_SIZE];
+	ssize_t rc;
+
+	if (count == 0) {
+		return 0;
+	} else if (count == MIN_NON_MSG_PKT_SIZE) {
+		/* Likely a harmless MSG_HELO or MSG_QUIT - no packet length */
+		goto memdup;
+	} else if (count < MIN_MSG_PKT_SIZE || count > MAX_MSG_PKT_SIZE) {
+		printk(KERN_WARNING "%s: Acceptable packet size range is "
+		       "[%d-%zu], but amount of data written is [%zu].\n",
+		       __func__, MIN_MSG_PKT_SIZE, MAX_MSG_PKT_SIZE, count);
+		return -EINVAL;
+	}
+
+	if (copy_from_user(packet_size_peek, &buf[PKT_LEN_OFFSET],
+			   sizeof(packet_size_peek))) {
+		printk(KERN_WARNING "%s: Error while inspecting packet size\n",
+		       __func__);
+		return -EFAULT;
+	}
+
+	rc = ecryptfs_parse_packet_length(packet_size_peek, &packet_size,
+					  &packet_size_length);
+	if (rc) {
+		printk(KERN_WARNING "%s: Error parsing packet length; "
+		       "rc = [%zd]\n", __func__, rc);
+		return rc;
+	}
+
+	if ((PKT_TYPE_SIZE + PKT_CTR_SIZE + packet_size_length + packet_size)
+	    != count) {
+		printk(KERN_WARNING "%s: Invalid packet size [%zu]\n", __func__,
+		       packet_size);
+		return -EINVAL;
+	}
+
+memdup:
+	data = memdup_user(buf, count);
+	if (IS_ERR(data)) {
+		printk(KERN_ERR "%s: memdup_user returned error [%ld]\n",
+		       __func__, PTR_ERR(data));
+		return PTR_ERR(data);
+	}
+	switch (data[PKT_TYPE_OFFSET]) {
+	case ECRYPTFS_MSG_RESPONSE:
+		if (count < (MIN_MSG_PKT_SIZE
+			     + sizeof(struct ecryptfs_message))) {
+			printk(KERN_WARNING "%s: Minimum acceptable packet "
+			       "size is [%zd], but amount of data written is "
+			       "only [%zd]. Discarding response packet.\n",
+			       __func__,
+			       (MIN_MSG_PKT_SIZE
+				+ sizeof(struct ecryptfs_message)), count);
+			rc = -EINVAL;
+			goto out_free;
+		}
+		memcpy(&counter_nbo, &data[PKT_CTR_OFFSET], PKT_CTR_SIZE);
+		seq = be32_to_cpu(counter_nbo);
+		rc = ecryptfs_miscdev_response(file->private_data,
+				&data[PKT_LEN_OFFSET + packet_size_length],
+				packet_size, seq);
+		if (rc) {
+			printk(KERN_WARNING "%s: Failed to deliver miscdev "
+			       "response to requesting operation; rc = [%zd]\n",
+			       __func__, rc);
+			goto out_free;
+		}
+		break;
+	case ECRYPTFS_MSG_HELO:
+	case ECRYPTFS_MSG_QUIT:
+		break;
+	default:
+		ecryptfs_printk(KERN_WARNING, "Dropping miscdev "
+				"message of unrecognized type [%d]\n",
+				data[0]);
+		rc = -EINVAL;
+		goto out_free;
+	}
+	rc = count;
+out_free:
+	kfree(data);
+	return rc;
+}
+
+
+static const struct file_operations ecryptfs_miscdev_fops = {
+	.owner   = THIS_MODULE,
+	.open    = ecryptfs_miscdev_open,
+	.poll    = ecryptfs_miscdev_poll,
+	.read    = ecryptfs_miscdev_read,
+	.write   = ecryptfs_miscdev_write,
+	.release = ecryptfs_miscdev_release,
+	.llseek  = noop_llseek,
+};
+
+static struct miscdevice ecryptfs_miscdev = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name  = "ecryptfs",
+	.fops  = &ecryptfs_miscdev_fops
+};
+
+/**
+ * ecryptfs_init_ecryptfs_miscdev
+ *
+ * Messages sent to the userspace daemon from the kernel are placed on
+ * a queue associated with the daemon. The next read against the
+ * miscdev handle by that daemon will return the oldest message placed
+ * on the message queue for the daemon.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int __init ecryptfs_init_ecryptfs_miscdev(void)
+{
+	int rc;
+
+	atomic_set(&ecryptfs_num_miscdev_opens, 0);
+	rc = misc_register(&ecryptfs_miscdev);
+	if (rc)
+		printk(KERN_ERR "%s: Failed to register miscellaneous device "
+		       "for communications with userspace daemons; rc = [%d]\n",
+		       __func__, rc);
+	return rc;
+}
+
+/**
+ * ecryptfs_destroy_ecryptfs_miscdev
+ *
+ * All of the daemons must be exorcised prior to calling this
+ * function.
+ */
+void ecryptfs_destroy_ecryptfs_miscdev(void)
+{
+	BUG_ON(atomic_read(&ecryptfs_num_miscdev_opens) != 0);
+	misc_deregister(&ecryptfs_miscdev);
+}
diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
new file mode 100644
index 000000000..e2483acc4
--- /dev/null
+++ b/fs/ecryptfs/mmap.c
@@ -0,0 +1,556 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * eCryptfs: Linux filesystem encryption layer
+ * This is where eCryptfs coordinates the symmetric encryption and
+ * decryption of the file data as it passes between the lower
+ * encrypted file and the upper decrypted file.
+ *
+ * Copyright (C) 1997-2003 Erez Zadok
+ * Copyright (C) 2001-2003 Stony Brook University
+ * Copyright (C) 2004-2007 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
+ */
+
+#include <linux/pagemap.h>
+#include <linux/writeback.h>
+#include <linux/page-flags.h>
+#include <linux/mount.h>
+#include <linux/file.h>
+#include <linux/scatterlist.h>
+#include <linux/slab.h>
+#include <linux/xattr.h>
+#include <asm/unaligned.h>
+#include "ecryptfs_kernel.h"
+
+/*
+ * ecryptfs_get_locked_page
+ *
+ * Get one page from cache or lower f/s, return error otherwise.
+ *
+ * Returns locked and up-to-date page (if ok), with increased
+ * refcnt.
+ */
+struct page *ecryptfs_get_locked_page(struct inode *inode, loff_t index)
+{
+	struct page *page = read_mapping_page(inode->i_mapping, index, NULL);
+	if (!IS_ERR(page))
+		lock_page(page);
+	return page;
+}
+
+/**
+ * ecryptfs_writepage
+ * @page: Page that is locked before this call is made
+ * @wbc: Write-back control structure
+ *
+ * Returns zero on success; non-zero otherwise
+ *
+ * This is where we encrypt the data and pass the encrypted data to
+ * the lower filesystem.  In OpenPGP-compatible mode, we operate on
+ * entire underlying packets.
+ */
+static int ecryptfs_writepage(struct page *page, struct writeback_control *wbc)
+{
+	int rc;
+
+	rc = ecryptfs_encrypt_page(page);
+	if (rc) {
+		ecryptfs_printk(KERN_WARNING, "Error encrypting "
+				"page (upper index [0x%.16lx])\n", page->index);
+		ClearPageUptodate(page);
+		goto out;
+	}
+	SetPageUptodate(page);
+out:
+	unlock_page(page);
+	return rc;
+}
+
+static void strip_xattr_flag(char *page_virt,
+			     struct ecryptfs_crypt_stat *crypt_stat)
+{
+	if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {
+		size_t written;
+
+		crypt_stat->flags &= ~ECRYPTFS_METADATA_IN_XATTR;
+		ecryptfs_write_crypt_stat_flags(page_virt, crypt_stat,
+						&written);
+		crypt_stat->flags |= ECRYPTFS_METADATA_IN_XATTR;
+	}
+}
+
+/*
+ *   Header Extent:
+ *     Octets 0-7:        Unencrypted file size (big-endian)
+ *     Octets 8-15:       eCryptfs special marker
+ *     Octets 16-19:      Flags
+ *      Octet 16:         File format version number (between 0 and 255)
+ *      Octets 17-18:     Reserved
+ *      Octet 19:         Bit 1 (lsb): Reserved
+ *                        Bit 2: Encrypted?
+ *                        Bits 3-8: Reserved
+ *     Octets 20-23:      Header extent size (big-endian)
+ *     Octets 24-25:      Number of header extents at front of file
+ *                        (big-endian)
+ *     Octet  26:         Begin RFC 2440 authentication token packet set
+ */
+
+/**
+ * ecryptfs_copy_up_encrypted_with_header
+ * @page: Sort of a ``virtual'' representation of the encrypted lower
+ *        file. The actual lower file does not have the metadata in
+ *        the header. This is locked.
+ * @crypt_stat: The eCryptfs inode's cryptographic context
+ *
+ * The ``view'' is the version of the file that userspace winds up
+ * seeing, with the header information inserted.
+ */
+static int
+ecryptfs_copy_up_encrypted_with_header(struct page *page,
+				       struct ecryptfs_crypt_stat *crypt_stat)
+{
+	loff_t extent_num_in_page = 0;
+	loff_t num_extents_per_page = (PAGE_SIZE
+				       / crypt_stat->extent_size);
+	int rc = 0;
+
+	while (extent_num_in_page < num_extents_per_page) {
+		loff_t view_extent_num = ((((loff_t)page->index)
+					   * num_extents_per_page)
+					  + extent_num_in_page);
+		size_t num_header_extents_at_front =
+			(crypt_stat->metadata_size / crypt_stat->extent_size);
+
+		if (view_extent_num < num_header_extents_at_front) {
+			/* This is a header extent */
+			char *page_virt;
+
+			page_virt = kmap_local_page(page);
+			memset(page_virt, 0, PAGE_SIZE);
+			/* TODO: Support more than one header extent */
+			if (view_extent_num == 0) {
+				size_t written;
+
+				rc = ecryptfs_read_xattr_region(
+					page_virt, page->mapping->host);
+				strip_xattr_flag(page_virt + 16, crypt_stat);
+				ecryptfs_write_header_metadata(page_virt + 20,
+							       crypt_stat,
+							       &written);
+			}
+			kunmap_local(page_virt);
+			flush_dcache_page(page);
+			if (rc) {
+				printk(KERN_ERR "%s: Error reading xattr "
+				       "region; rc = [%d]\n", __func__, rc);
+				goto out;
+			}
+		} else {
+			/* This is an encrypted data extent */
+			loff_t lower_offset =
+				((view_extent_num * crypt_stat->extent_size)
+				 - crypt_stat->metadata_size);
+
+			rc = ecryptfs_read_lower_page_segment(
+				page, (lower_offset >> PAGE_SHIFT),
+				(lower_offset & ~PAGE_MASK),
+				crypt_stat->extent_size, page->mapping->host);
+			if (rc) {
+				printk(KERN_ERR "%s: Error attempting to read "
+				       "extent at offset [%lld] in the lower "
+				       "file; rc = [%d]\n", __func__,
+				       lower_offset, rc);
+				goto out;
+			}
+		}
+		extent_num_in_page++;
+	}
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_read_folio
+ * @file: An eCryptfs file
+ * @folio: Folio from eCryptfs inode mapping into which to stick the read data
+ *
+ * Read in a folio, decrypting if necessary.
+ *
+ * Returns zero on success; non-zero on error.
+ */
+static int ecryptfs_read_folio(struct file *file, struct folio *folio)
+{
+	struct page *page = &folio->page;
+	struct ecryptfs_crypt_stat *crypt_stat =
+		&ecryptfs_inode_to_private(page->mapping->host)->crypt_stat;
+	int rc = 0;
+
+	if (!crypt_stat || !(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
+		rc = ecryptfs_read_lower_page_segment(page, page->index, 0,
+						      PAGE_SIZE,
+						      page->mapping->host);
+	} else if (crypt_stat->flags & ECRYPTFS_VIEW_AS_ENCRYPTED) {
+		if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {
+			rc = ecryptfs_copy_up_encrypted_with_header(page,
+								    crypt_stat);
+			if (rc) {
+				printk(KERN_ERR "%s: Error attempting to copy "
+				       "the encrypted content from the lower "
+				       "file whilst inserting the metadata "
+				       "from the xattr into the header; rc = "
+				       "[%d]\n", __func__, rc);
+				goto out;
+			}
+
+		} else {
+			rc = ecryptfs_read_lower_page_segment(
+				page, page->index, 0, PAGE_SIZE,
+				page->mapping->host);
+			if (rc) {
+				printk(KERN_ERR "Error reading page; rc = "
+				       "[%d]\n", rc);
+				goto out;
+			}
+		}
+	} else {
+		rc = ecryptfs_decrypt_page(page);
+		if (rc) {
+			ecryptfs_printk(KERN_ERR, "Error decrypting page; "
+					"rc = [%d]\n", rc);
+			goto out;
+		}
+	}
+out:
+	if (rc)
+		ClearPageUptodate(page);
+	else
+		SetPageUptodate(page);
+	ecryptfs_printk(KERN_DEBUG, "Unlocking page with index = [0x%.16lx]\n",
+			page->index);
+	unlock_page(page);
+	return rc;
+}
+
+/*
+ * Called with lower inode mutex held.
+ */
+static int fill_zeros_to_end_of_page(struct page *page, unsigned int to)
+{
+	struct inode *inode = page->mapping->host;
+	int end_byte_in_page;
+
+	if ((i_size_read(inode) / PAGE_SIZE) != page->index)
+		goto out;
+	end_byte_in_page = i_size_read(inode) % PAGE_SIZE;
+	if (to > end_byte_in_page)
+		end_byte_in_page = to;
+	zero_user_segment(page, end_byte_in_page, PAGE_SIZE);
+out:
+	return 0;
+}
+
+/**
+ * ecryptfs_write_begin
+ * @file: The eCryptfs file
+ * @mapping: The eCryptfs object
+ * @pos: The file offset at which to start writing
+ * @len: Length of the write
+ * @pagep: Pointer to return the page
+ * @fsdata: Pointer to return fs data (unused)
+ *
+ * This function must zero any hole we create
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+static int ecryptfs_write_begin(struct file *file,
+			struct address_space *mapping,
+			loff_t pos, unsigned len,
+			struct page **pagep, void **fsdata)
+{
+	pgoff_t index = pos >> PAGE_SHIFT;
+	struct page *page;
+	loff_t prev_page_end_size;
+	int rc = 0;
+
+	page = grab_cache_page_write_begin(mapping, index);
+	if (!page)
+		return -ENOMEM;
+	*pagep = page;
+
+	prev_page_end_size = ((loff_t)index << PAGE_SHIFT);
+	if (!PageUptodate(page)) {
+		struct ecryptfs_crypt_stat *crypt_stat =
+			&ecryptfs_inode_to_private(mapping->host)->crypt_stat;
+
+		if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
+			rc = ecryptfs_read_lower_page_segment(
+				page, index, 0, PAGE_SIZE, mapping->host);
+			if (rc) {
+				printk(KERN_ERR "%s: Error attempting to read "
+				       "lower page segment; rc = [%d]\n",
+				       __func__, rc);
+				ClearPageUptodate(page);
+				goto out;
+			} else
+				SetPageUptodate(page);
+		} else if (crypt_stat->flags & ECRYPTFS_VIEW_AS_ENCRYPTED) {
+			if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR) {
+				rc = ecryptfs_copy_up_encrypted_with_header(
+					page, crypt_stat);
+				if (rc) {
+					printk(KERN_ERR "%s: Error attempting "
+					       "to copy the encrypted content "
+					       "from the lower file whilst "
+					       "inserting the metadata from "
+					       "the xattr into the header; rc "
+					       "= [%d]\n", __func__, rc);
+					ClearPageUptodate(page);
+					goto out;
+				}
+				SetPageUptodate(page);
+			} else {
+				rc = ecryptfs_read_lower_page_segment(
+					page, index, 0, PAGE_SIZE,
+					mapping->host);
+				if (rc) {
+					printk(KERN_ERR "%s: Error reading "
+					       "page; rc = [%d]\n",
+					       __func__, rc);
+					ClearPageUptodate(page);
+					goto out;
+				}
+				SetPageUptodate(page);
+			}
+		} else {
+			if (prev_page_end_size
+			    >= i_size_read(page->mapping->host)) {
+				zero_user(page, 0, PAGE_SIZE);
+				SetPageUptodate(page);
+			} else if (len < PAGE_SIZE) {
+				rc = ecryptfs_decrypt_page(page);
+				if (rc) {
+					printk(KERN_ERR "%s: Error decrypting "
+					       "page at index [%ld]; "
+					       "rc = [%d]\n",
+					       __func__, page->index, rc);
+					ClearPageUptodate(page);
+					goto out;
+				}
+				SetPageUptodate(page);
+			}
+		}
+	}
+	/* If creating a page or more of holes, zero them out via truncate.
+	 * Note, this will increase i_size. */
+	if (index != 0) {
+		if (prev_page_end_size > i_size_read(page->mapping->host)) {
+			rc = ecryptfs_truncate(file->f_path.dentry,
+					       prev_page_end_size);
+			if (rc) {
+				printk(KERN_ERR "%s: Error on attempt to "
+				       "truncate to (higher) offset [%lld];"
+				       " rc = [%d]\n", __func__,
+				       prev_page_end_size, rc);
+				goto out;
+			}
+		}
+	}
+	/* Writing to a new page, and creating a small hole from start
+	 * of page?  Zero it out. */
+	if ((i_size_read(mapping->host) == prev_page_end_size)
+	    && (pos != 0))
+		zero_user(page, 0, PAGE_SIZE);
+out:
+	if (unlikely(rc)) {
+		unlock_page(page);
+		put_page(page);
+		*pagep = NULL;
+	}
+	return rc;
+}
+
+/*
+ * ecryptfs_write_inode_size_to_header
+ *
+ * Writes the lower file size to the first 8 bytes of the header.
+ *
+ * Returns zero on success; non-zero on error.
+ */
+static int ecryptfs_write_inode_size_to_header(struct inode *ecryptfs_inode)
+{
+	char *file_size_virt;
+	int rc;
+
+	file_size_virt = kmalloc(sizeof(u64), GFP_KERNEL);
+	if (!file_size_virt) {
+		rc = -ENOMEM;
+		goto out;
+	}
+	put_unaligned_be64(i_size_read(ecryptfs_inode), file_size_virt);
+	rc = ecryptfs_write_lower(ecryptfs_inode, file_size_virt, 0,
+				  sizeof(u64));
+	kfree(file_size_virt);
+	if (rc < 0)
+		printk(KERN_ERR "%s: Error writing file size to header; "
+		       "rc = [%d]\n", __func__, rc);
+	else
+		rc = 0;
+out:
+	return rc;
+}
+
+struct kmem_cache *ecryptfs_xattr_cache;
+
+static int ecryptfs_write_inode_size_to_xattr(struct inode *ecryptfs_inode)
+{
+	ssize_t size;
+	void *xattr_virt;
+	struct dentry *lower_dentry =
+		ecryptfs_inode_to_private(ecryptfs_inode)->lower_file->f_path.dentry;
+	struct inode *lower_inode = d_inode(lower_dentry);
+	int rc;
+
+	if (!(lower_inode->i_opflags & IOP_XATTR)) {
+		printk(KERN_WARNING
+		       "No support for setting xattr in lower filesystem\n");
+		rc = -ENOSYS;
+		goto out;
+	}
+	xattr_virt = kmem_cache_alloc(ecryptfs_xattr_cache, GFP_KERNEL);
+	if (!xattr_virt) {
+		rc = -ENOMEM;
+		goto out;
+	}
+	inode_lock(lower_inode);
+	size = __vfs_getxattr(lower_dentry, lower_inode, ECRYPTFS_XATTR_NAME,
+			      xattr_virt, PAGE_SIZE);
+	if (size < 0)
+		size = 8;
+	put_unaligned_be64(i_size_read(ecryptfs_inode), xattr_virt);
+	rc = __vfs_setxattr(&nop_mnt_idmap, lower_dentry, lower_inode,
+			    ECRYPTFS_XATTR_NAME, xattr_virt, size, 0);
+	inode_unlock(lower_inode);
+	if (rc)
+		printk(KERN_ERR "Error whilst attempting to write inode size "
+		       "to lower file xattr; rc = [%d]\n", rc);
+	kmem_cache_free(ecryptfs_xattr_cache, xattr_virt);
+out:
+	return rc;
+}
+
+int ecryptfs_write_inode_size_to_metadata(struct inode *ecryptfs_inode)
+{
+	struct ecryptfs_crypt_stat *crypt_stat;
+
+	crypt_stat = &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
+	BUG_ON(!(crypt_stat->flags & ECRYPTFS_ENCRYPTED));
+	if (crypt_stat->flags & ECRYPTFS_METADATA_IN_XATTR)
+		return ecryptfs_write_inode_size_to_xattr(ecryptfs_inode);
+	else
+		return ecryptfs_write_inode_size_to_header(ecryptfs_inode);
+}
+
+/**
+ * ecryptfs_write_end
+ * @file: The eCryptfs file object
+ * @mapping: The eCryptfs object
+ * @pos: The file position
+ * @len: The length of the data (unused)
+ * @copied: The amount of data copied
+ * @page: The eCryptfs page
+ * @fsdata: The fsdata (unused)
+ */
+static int ecryptfs_write_end(struct file *file,
+			struct address_space *mapping,
+			loff_t pos, unsigned len, unsigned copied,
+			struct page *page, void *fsdata)
+{
+	pgoff_t index = pos >> PAGE_SHIFT;
+	unsigned from = pos & (PAGE_SIZE - 1);
+	unsigned to = from + copied;
+	struct inode *ecryptfs_inode = mapping->host;
+	struct ecryptfs_crypt_stat *crypt_stat =
+		&ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
+	int rc;
+
+	ecryptfs_printk(KERN_DEBUG, "Calling fill_zeros_to_end_of_page"
+			"(page w/ index = [0x%.16lx], to = [%d])\n", index, to);
+	if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) {
+		rc = ecryptfs_write_lower_page_segment(ecryptfs_inode, page, 0,
+						       to);
+		if (!rc) {
+			rc = copied;
+			fsstack_copy_inode_size(ecryptfs_inode,
+				ecryptfs_inode_to_lower(ecryptfs_inode));
+		}
+		goto out;
+	}
+	if (!PageUptodate(page)) {
+		if (copied < PAGE_SIZE) {
+			rc = 0;
+			goto out;
+		}
+		SetPageUptodate(page);
+	}
+	/* Fills in zeros if 'to' goes beyond inode size */
+	rc = fill_zeros_to_end_of_page(page, to);
+	if (rc) {
+		ecryptfs_printk(KERN_WARNING, "Error attempting to fill "
+			"zeros in page with index = [0x%.16lx]\n", index);
+		goto out;
+	}
+	rc = ecryptfs_encrypt_page(page);
+	if (rc) {
+		ecryptfs_printk(KERN_WARNING, "Error encrypting page (upper "
+				"index [0x%.16lx])\n", index);
+		goto out;
+	}
+	if (pos + copied > i_size_read(ecryptfs_inode)) {
+		i_size_write(ecryptfs_inode, pos + copied);
+		ecryptfs_printk(KERN_DEBUG, "Expanded file size to "
+			"[0x%.16llx]\n",
+			(unsigned long long)i_size_read(ecryptfs_inode));
+	}
+	rc = ecryptfs_write_inode_size_to_metadata(ecryptfs_inode);
+	if (rc)
+		printk(KERN_ERR "Error writing inode size to metadata; "
+		       "rc = [%d]\n", rc);
+	else
+		rc = copied;
+out:
+	unlock_page(page);
+	put_page(page);
+	return rc;
+}
+
+static sector_t ecryptfs_bmap(struct address_space *mapping, sector_t block)
+{
+	struct inode *lower_inode = ecryptfs_inode_to_lower(mapping->host);
+	int ret = bmap(lower_inode, &block);
+
+	if (ret)
+		return 0;
+	return block;
+}
+
+#include <linux/buffer_head.h>
+
+const struct address_space_operations ecryptfs_aops = {
+	/*
+	 * XXX: This is pretty broken for multiple reasons: ecryptfs does not
+	 * actually use buffer_heads, and ecryptfs will crash without
+	 * CONFIG_BLOCK.  But it matches the behavior before the default for
+	 * address_space_operations without the ->dirty_folio method was
+	 * cleaned up, so this is the best we can do without maintainer
+	 * feedback.
+	 */
+#ifdef CONFIG_BLOCK
+	.dirty_folio	= block_dirty_folio,
+	.invalidate_folio = block_invalidate_folio,
+#endif
+	.writepage = ecryptfs_writepage,
+	.read_folio = ecryptfs_read_folio,
+	.write_begin = ecryptfs_write_begin,
+	.write_end = ecryptfs_write_end,
+	.bmap = ecryptfs_bmap,
+};
diff --git a/fs/ecryptfs/read_write.c b/fs/ecryptfs/read_write.c
new file mode 100644
index 000000000..3458f153a
--- /dev/null
+++ b/fs/ecryptfs/read_write.c
@@ -0,0 +1,263 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 2007 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
+ */
+
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/sched/signal.h>
+
+#include "ecryptfs_kernel.h"
+
+/**
+ * ecryptfs_write_lower
+ * @ecryptfs_inode: The eCryptfs inode
+ * @data: Data to write
+ * @offset: Byte offset in the lower file to which to write the data
+ * @size: Number of bytes from @data to write at @offset in the lower
+ *        file
+ *
+ * Write data to the lower file.
+ *
+ * Returns bytes written on success; less than zero on error
+ */
+int ecryptfs_write_lower(struct inode *ecryptfs_inode, char *data,
+			 loff_t offset, size_t size)
+{
+	struct file *lower_file;
+	ssize_t rc;
+
+	lower_file = ecryptfs_inode_to_private(ecryptfs_inode)->lower_file;
+	if (!lower_file)
+		return -EIO;
+	rc = kernel_write(lower_file, data, size, &offset);
+	mark_inode_dirty_sync(ecryptfs_inode);
+	return rc;
+}
+
+/**
+ * ecryptfs_write_lower_page_segment
+ * @ecryptfs_inode: The eCryptfs inode
+ * @page_for_lower: The page containing the data to be written to the
+ *                  lower file
+ * @offset_in_page: The offset in the @page_for_lower from which to
+ *                  start writing the data
+ * @size: The amount of data from @page_for_lower to write to the
+ *        lower file
+ *
+ * Determines the byte offset in the file for the given page and
+ * offset within the page, maps the page, and makes the call to write
+ * the contents of @page_for_lower to the lower inode.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int ecryptfs_write_lower_page_segment(struct inode *ecryptfs_inode,
+				      struct page *page_for_lower,
+				      size_t offset_in_page, size_t size)
+{
+	char *virt;
+	loff_t offset;
+	int rc;
+
+	offset = ((((loff_t)page_for_lower->index) << PAGE_SHIFT)
+		  + offset_in_page);
+	virt = kmap_local_page(page_for_lower);
+	rc = ecryptfs_write_lower(ecryptfs_inode, virt, offset, size);
+	if (rc > 0)
+		rc = 0;
+	kunmap_local(virt);
+	return rc;
+}
+
+/**
+ * ecryptfs_write
+ * @ecryptfs_inode: The eCryptfs file into which to write
+ * @data: Virtual address where data to write is located
+ * @offset: Offset in the eCryptfs file at which to begin writing the
+ *          data from @data
+ * @size: The number of bytes to write from @data
+ *
+ * Write an arbitrary amount of data to an arbitrary location in the
+ * eCryptfs inode page cache. This is done on a page-by-page, and then
+ * by an extent-by-extent, basis; individual extents are encrypted and
+ * written to the lower page cache (via VFS writes). This function
+ * takes care of all the address translation to locations in the lower
+ * filesystem; it also handles truncate events, writing out zeros
+ * where necessary.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int ecryptfs_write(struct inode *ecryptfs_inode, char *data, loff_t offset,
+		   size_t size)
+{
+	struct page *ecryptfs_page;
+	struct ecryptfs_crypt_stat *crypt_stat;
+	char *ecryptfs_page_virt;
+	loff_t ecryptfs_file_size = i_size_read(ecryptfs_inode);
+	loff_t data_offset = 0;
+	loff_t pos;
+	int rc = 0;
+
+	crypt_stat = &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat;
+	/*
+	 * if we are writing beyond current size, then start pos
+	 * at the current size - we'll fill in zeros from there.
+	 */
+	if (offset > ecryptfs_file_size)
+		pos = ecryptfs_file_size;
+	else
+		pos = offset;
+	while (pos < (offset + size)) {
+		pgoff_t ecryptfs_page_idx = (pos >> PAGE_SHIFT);
+		size_t start_offset_in_page = (pos & ~PAGE_MASK);
+		size_t num_bytes = (PAGE_SIZE - start_offset_in_page);
+		loff_t total_remaining_bytes = ((offset + size) - pos);
+
+		if (fatal_signal_pending(current)) {
+			rc = -EINTR;
+			break;
+		}
+
+		if (num_bytes > total_remaining_bytes)
+			num_bytes = total_remaining_bytes;
+		if (pos < offset) {
+			/* remaining zeros to write, up to destination offset */
+			loff_t total_remaining_zeros = (offset - pos);
+
+			if (num_bytes > total_remaining_zeros)
+				num_bytes = total_remaining_zeros;
+		}
+		ecryptfs_page = ecryptfs_get_locked_page(ecryptfs_inode,
+							 ecryptfs_page_idx);
+		if (IS_ERR(ecryptfs_page)) {
+			rc = PTR_ERR(ecryptfs_page);
+			printk(KERN_ERR "%s: Error getting page at "
+			       "index [%ld] from eCryptfs inode "
+			       "mapping; rc = [%d]\n", __func__,
+			       ecryptfs_page_idx, rc);
+			goto out;
+		}
+		ecryptfs_page_virt = kmap_local_page(ecryptfs_page);
+
+		/*
+		 * pos: where we're now writing, offset: where the request was
+		 * If current pos is before request, we are filling zeros
+		 * If we are at or beyond request, we are writing the *data*
+		 * If we're in a fresh page beyond eof, zero it in either case
+		 */
+		if (pos < offset || !start_offset_in_page) {
+			/* We are extending past the previous end of the file.
+			 * Fill in zero values to the end of the page */
+			memset(((char *)ecryptfs_page_virt
+				+ start_offset_in_page), 0,
+				PAGE_SIZE - start_offset_in_page);
+		}
+
+		/* pos >= offset, we are now writing the data request */
+		if (pos >= offset) {
+			memcpy(((char *)ecryptfs_page_virt
+				+ start_offset_in_page),
+			       (data + data_offset), num_bytes);
+			data_offset += num_bytes;
+		}
+		kunmap_local(ecryptfs_page_virt);
+		flush_dcache_page(ecryptfs_page);
+		SetPageUptodate(ecryptfs_page);
+		unlock_page(ecryptfs_page);
+		if (crypt_stat->flags & ECRYPTFS_ENCRYPTED)
+			rc = ecryptfs_encrypt_page(ecryptfs_page);
+		else
+			rc = ecryptfs_write_lower_page_segment(ecryptfs_inode,
+						ecryptfs_page,
+						start_offset_in_page,
+						data_offset);
+		put_page(ecryptfs_page);
+		if (rc) {
+			printk(KERN_ERR "%s: Error encrypting "
+			       "page; rc = [%d]\n", __func__, rc);
+			goto out;
+		}
+		pos += num_bytes;
+	}
+	if (pos > ecryptfs_file_size) {
+		i_size_write(ecryptfs_inode, pos);
+		if (crypt_stat->flags & ECRYPTFS_ENCRYPTED) {
+			int rc2;
+
+			rc2 = ecryptfs_write_inode_size_to_metadata(
+								ecryptfs_inode);
+			if (rc2) {
+				printk(KERN_ERR	"Problem with "
+				       "ecryptfs_write_inode_size_to_metadata; "
+				       "rc = [%d]\n", rc2);
+				if (!rc)
+					rc = rc2;
+				goto out;
+			}
+		}
+	}
+out:
+	return rc;
+}
+
+/**
+ * ecryptfs_read_lower
+ * @data: The read data is stored here by this function
+ * @offset: Byte offset in the lower file from which to read the data
+ * @size: Number of bytes to read from @offset of the lower file and
+ *        store into @data
+ * @ecryptfs_inode: The eCryptfs inode
+ *
+ * Read @size bytes of data at byte offset @offset from the lower
+ * inode into memory location @data.
+ *
+ * Returns bytes read on success; 0 on EOF; less than zero on error
+ */
+int ecryptfs_read_lower(char *data, loff_t offset, size_t size,
+			struct inode *ecryptfs_inode)
+{
+	struct file *lower_file;
+	lower_file = ecryptfs_inode_to_private(ecryptfs_inode)->lower_file;
+	if (!lower_file)
+		return -EIO;
+	return kernel_read(lower_file, data, size, &offset);
+}
+
+/**
+ * ecryptfs_read_lower_page_segment
+ * @page_for_ecryptfs: The page into which data for eCryptfs will be
+ *                     written
+ * @page_index: Page index in @page_for_ecryptfs from which to start
+ *		writing
+ * @offset_in_page: Offset in @page_for_ecryptfs from which to start
+ *                  writing
+ * @size: The number of bytes to write into @page_for_ecryptfs
+ * @ecryptfs_inode: The eCryptfs inode
+ *
+ * Determines the byte offset in the file for the given page and
+ * offset within the page, maps the page, and makes the call to read
+ * the contents of @page_for_ecryptfs from the lower inode.
+ *
+ * Returns zero on success; non-zero otherwise
+ */
+int ecryptfs_read_lower_page_segment(struct page *page_for_ecryptfs,
+				     pgoff_t page_index,
+				     size_t offset_in_page, size_t size,
+				     struct inode *ecryptfs_inode)
+{
+	char *virt;
+	loff_t offset;
+	int rc;
+
+	offset = ((((loff_t)page_index) << PAGE_SHIFT) + offset_in_page);
+	virt = kmap_local_page(page_for_ecryptfs);
+	rc = ecryptfs_read_lower(virt, offset, size, ecryptfs_inode);
+	if (rc > 0)
+		rc = 0;
+	kunmap_local(virt);
+	flush_dcache_page(page_for_ecryptfs);
+	return rc;
+}
diff --git a/fs/ecryptfs/super.c b/fs/ecryptfs/super.c
new file mode 100644
index 000000000..0b1c87831
--- /dev/null
+++ b/fs/ecryptfs/super.c
@@ -0,0 +1,178 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * eCryptfs: Linux filesystem encryption layer
+ *
+ * Copyright (C) 1997-2003 Erez Zadok
+ * Copyright (C) 2001-2003 Stony Brook University
+ * Copyright (C) 2004-2006 International Business Machines Corp.
+ *   Author(s): Michael A. Halcrow <mahalcro@us.ibm.com>
+ *              Michael C. Thompson <mcthomps@us.ibm.com>
+ */
+
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/key.h>
+#include <linux/slab.h>
+#include <linux/seq_file.h>
+#include <linux/file.h>
+#include <linux/statfs.h>
+#include <linux/magic.h>
+#include "ecryptfs_kernel.h"
+
+struct kmem_cache *ecryptfs_inode_info_cache;
+
+/**
+ * ecryptfs_alloc_inode - allocate an ecryptfs inode
+ * @sb: Pointer to the ecryptfs super block
+ *
+ * Called to bring an inode into existence.
+ *
+ * Only handle allocation, setting up structures should be done in
+ * ecryptfs_read_inode. This is because the kernel, between now and
+ * then, will 0 out the private data pointer.
+ *
+ * Returns a pointer to a newly allocated inode, NULL otherwise
+ */
+static struct inode *ecryptfs_alloc_inode(struct super_block *sb)
+{
+	struct ecryptfs_inode_info *inode_info;
+	struct inode *inode = NULL;
+
+	inode_info = alloc_inode_sb(sb, ecryptfs_inode_info_cache, GFP_KERNEL);
+	if (unlikely(!inode_info))
+		goto out;
+	if (ecryptfs_init_crypt_stat(&inode_info->crypt_stat)) {
+		kmem_cache_free(ecryptfs_inode_info_cache, inode_info);
+		goto out;
+	}
+	mutex_init(&inode_info->lower_file_mutex);
+	atomic_set(&inode_info->lower_file_count, 0);
+	inode_info->lower_file = NULL;
+	inode = &inode_info->vfs_inode;
+out:
+	return inode;
+}
+
+static void ecryptfs_free_inode(struct inode *inode)
+{
+	struct ecryptfs_inode_info *inode_info;
+	inode_info = ecryptfs_inode_to_private(inode);
+
+	kmem_cache_free(ecryptfs_inode_info_cache, inode_info);
+}
+
+/**
+ * ecryptfs_destroy_inode
+ * @inode: The ecryptfs inode
+ *
+ * This is used during the final destruction of the inode.  All
+ * allocation of memory related to the inode, including allocated
+ * memory in the crypt_stat struct, will be released here.
+ * There should be no chance that this deallocation will be missed.
+ */
+static void ecryptfs_destroy_inode(struct inode *inode)
+{
+	struct ecryptfs_inode_info *inode_info;
+
+	inode_info = ecryptfs_inode_to_private(inode);
+	BUG_ON(inode_info->lower_file);
+	ecryptfs_destroy_crypt_stat(&inode_info->crypt_stat);
+}
+
+/**
+ * ecryptfs_statfs
+ * @dentry: The ecryptfs dentry
+ * @buf: The struct kstatfs to fill in with stats
+ *
+ * Get the filesystem statistics. Currently, we let this pass right through
+ * to the lower filesystem and take no action ourselves.
+ */
+static int ecryptfs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
+	int rc;
+
+	if (!lower_dentry->d_sb->s_op->statfs)
+		return -ENOSYS;
+
+	rc = lower_dentry->d_sb->s_op->statfs(lower_dentry, buf);
+	if (rc)
+		return rc;
+
+	buf->f_type = ECRYPTFS_SUPER_MAGIC;
+	rc = ecryptfs_set_f_namelen(&buf->f_namelen, buf->f_namelen,
+	       &ecryptfs_superblock_to_private(dentry->d_sb)->mount_crypt_stat);
+
+	return rc;
+}
+
+/**
+ * ecryptfs_evict_inode
+ * @inode: The ecryptfs inode
+ *
+ * Called by iput() when the inode reference count reached zero
+ * and the inode is not hashed anywhere.  Used to clear anything
+ * that needs to be, before the inode is completely destroyed and put
+ * on the inode free list. We use this to drop out reference to the
+ * lower inode.
+ */
+static void ecryptfs_evict_inode(struct inode *inode)
+{
+	truncate_inode_pages_final(&inode->i_data);
+	clear_inode(inode);
+	iput(ecryptfs_inode_to_lower(inode));
+}
+
+/*
+ * ecryptfs_show_options
+ *
+ * Prints the mount options for a given superblock.
+ * Returns zero; does not fail.
+ */
+static int ecryptfs_show_options(struct seq_file *m, struct dentry *root)
+{
+	struct super_block *sb = root->d_sb;
+	struct ecryptfs_mount_crypt_stat *mount_crypt_stat =
+		&ecryptfs_superblock_to_private(sb)->mount_crypt_stat;
+	struct ecryptfs_global_auth_tok *walker;
+
+	mutex_lock(&mount_crypt_stat->global_auth_tok_list_mutex);
+	list_for_each_entry(walker,
+			    &mount_crypt_stat->global_auth_tok_list,
+			    mount_crypt_stat_list) {
+		if (walker->flags & ECRYPTFS_AUTH_TOK_FNEK)
+			seq_printf(m, ",ecryptfs_fnek_sig=%s", walker->sig);
+		else
+			seq_printf(m, ",ecryptfs_sig=%s", walker->sig);
+	}
+	mutex_unlock(&mount_crypt_stat->global_auth_tok_list_mutex);
+
+	seq_printf(m, ",ecryptfs_cipher=%s",
+		mount_crypt_stat->global_default_cipher_name);
+
+	if (mount_crypt_stat->global_default_cipher_key_size)
+		seq_printf(m, ",ecryptfs_key_bytes=%zd",
+			   mount_crypt_stat->global_default_cipher_key_size);
+	if (mount_crypt_stat->flags & ECRYPTFS_PLAINTEXT_PASSTHROUGH_ENABLED)
+		seq_printf(m, ",ecryptfs_passthrough");
+	if (mount_crypt_stat->flags & ECRYPTFS_XATTR_METADATA_ENABLED)
+		seq_printf(m, ",ecryptfs_xattr_metadata");
+	if (mount_crypt_stat->flags & ECRYPTFS_ENCRYPTED_VIEW_ENABLED)
+		seq_printf(m, ",ecryptfs_encrypted_view");
+	if (mount_crypt_stat->flags & ECRYPTFS_UNLINK_SIGS)
+		seq_printf(m, ",ecryptfs_unlink_sigs");
+	if (mount_crypt_stat->flags & ECRYPTFS_GLOBAL_MOUNT_AUTH_TOK_ONLY)
+		seq_printf(m, ",ecryptfs_mount_auth_tok_only");
+
+	return 0;
+}
+
+const struct super_operations ecryptfs_sops = {
+	.alloc_inode = ecryptfs_alloc_inode,
+	.destroy_inode = ecryptfs_destroy_inode,
+	.free_inode = ecryptfs_free_inode,
+	.statfs = ecryptfs_statfs,
+	.remount_fs = NULL,
+	.evict_inode = ecryptfs_evict_inode,
+	.show_options = ecryptfs_show_options
+};