1 files changed, 418 insertions, 0 deletions
diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
new file mode 100644
index 000000000..268b74499
--- /dev/null
+++ b/fs/ecryptfs/file.c
@@ -0,0 +1,418 @@
+// 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;
+}
+
+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 = generic_file_splice_read,
+};