1 files changed, 96 insertions, 0 deletions
diff --git a/fs/ubifs/crypto.c b/fs/ubifs/crypto.c
new file mode 100644
index 000000000..3125e7637
--- /dev/null
+++ b/fs/ubifs/crypto.c
@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "ubifs.h"
+
+static int ubifs_crypt_get_context(struct inode *inode, void *ctx, size_t len)
+{
+	return ubifs_xattr_get(inode, UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT,
+			       ctx, len);
+}
+
+static int ubifs_crypt_set_context(struct inode *inode, const void *ctx,
+				   size_t len, void *fs_data)
+{
+	/*
+	 * Creating an encryption context is done unlocked since we
+	 * operate on a new inode which is not visible to other users
+	 * at this point. So, no need to check whether inode is locked.
+	 */
+	return ubifs_xattr_set(inode, UBIFS_XATTR_NAME_ENCRYPTION_CONTEXT,
+			       ctx, len, 0, false);
+}
+
+static bool ubifs_crypt_empty_dir(struct inode *inode)
+{
+	return ubifs_check_dir_empty(inode) == 0;
+}
+
+/**
+ * ubifs_encrypt - Encrypt data.
+ * @inode: inode which refers to the data node
+ * @dn: data node to encrypt
+ * @in_len: length of data to be compressed
+ * @out_len: allocated memory size for the data area of @dn
+ * @block: logical block number of the block
+ *
+ * This function encrypt a possibly-compressed data in the data node.
+ * The encrypted data length will store in @out_len.
+ */
+int ubifs_encrypt(const struct inode *inode, struct ubifs_data_node *dn,
+		  unsigned int in_len, unsigned int *out_len, int block)
+{
+	struct ubifs_info *c = inode->i_sb->s_fs_info;
+	void *p = &dn->data;
+	unsigned int pad_len = round_up(in_len, UBIFS_CIPHER_BLOCK_SIZE);
+	int err;
+
+	ubifs_assert(c, pad_len <= *out_len);
+	dn->compr_size = cpu_to_le16(in_len);
+
+	/* pad to full block cipher length */
+	if (pad_len != in_len)
+		memset(p + in_len, 0, pad_len - in_len);
+
+	err = fscrypt_encrypt_block_inplace(inode, virt_to_page(p), pad_len,
+					    offset_in_page(p), block, GFP_NOFS);
+	if (err) {
+		ubifs_err(c, "fscrypt_encrypt_block_inplace() failed: %d", err);
+		return err;
+	}
+	*out_len = pad_len;
+
+	return 0;
+}
+
+int ubifs_decrypt(const struct inode *inode, struct ubifs_data_node *dn,
+		  unsigned int *out_len, int block)
+{
+	struct ubifs_info *c = inode->i_sb->s_fs_info;
+	int err;
+	unsigned int clen = le16_to_cpu(dn->compr_size);
+	unsigned int dlen = *out_len;
+
+	if (clen <= 0 || clen > UBIFS_BLOCK_SIZE || clen > dlen) {
+		ubifs_err(c, "bad compr_size: %i", clen);
+		return -EINVAL;
+	}
+
+	ubifs_assert(c, dlen <= UBIFS_BLOCK_SIZE);
+	err = fscrypt_decrypt_block_inplace(inode, virt_to_page(&dn->data),
+					    dlen, offset_in_page(&dn->data),
+					    block);
+	if (err) {
+		ubifs_err(c, "fscrypt_decrypt_block_inplace() failed: %d", err);
+		return err;
+	}
+	*out_len = clen;
+
+	return 0;
+}
+
+const struct fscrypt_operations ubifs_crypt_operations = {
+	.flags			= FS_CFLG_OWN_PAGES,
+	.key_prefix		= "ubifs:",
+	.get_context		= ubifs_crypt_get_context,
+	.set_context		= ubifs_crypt_set_context,
+	.empty_dir		= ubifs_crypt_empty_dir,
+};