From: Theodore Ts'o <tytso@mit.edu>
Date: Thu, 16 Apr 2015 05:55:00 +0000 (-0400)
Subject: ext4 crypto: add symlink encryption
X-Git-Tag: omap-for-v4.2/o2_dc~79^2~1
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f348c252320b98e11176074fe04223f22bddaf0d;p=pandora-kernel.git

ext4 crypto: add symlink encryption

Signed-off-by: Uday Savagaonkar <savagaon@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 5146e67e8d51..86d15706d27a 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2233,6 +2233,7 @@ extern int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
 extern int ext4_trim_fs(struct super_block *, struct fstrim_range *);
 
 /* inode.c */
+int ext4_inode_is_fast_symlink(struct inode *inode);
 struct buffer_head *ext4_getblk(handle_t *, struct inode *, ext4_lblk_t, int);
 struct buffer_head *ext4_bread(handle_t *, struct inode *, ext4_lblk_t, int);
 int ext4_get_block_write(struct inode *inode, sector_t iblock,
diff --git a/fs/ext4/ext4_crypto.h b/fs/ext4/ext4_crypto.h
index f7d46e8dc9d3..c2ba35a914b6 100644
--- a/fs/ext4/ext4_crypto.h
+++ b/fs/ext4/ext4_crypto.h
@@ -124,4 +124,24 @@ struct ext4_fname_crypto_ctx {
 	unsigned ctfm_key_is_ready : 1;
 };
 
+/**
+ * For encrypted symlinks, the ciphertext length is stored at the beginning
+ * of the string in little-endian format.
+ */
+struct ext4_encrypted_symlink_data {
+	__le16 len;
+	char encrypted_path[1];
+} __attribute__((__packed__));
+
+/**
+ * This function is used to calculate the disk space required to
+ * store a filename of length l in encrypted symlink format.
+ */
+static inline u32 encrypted_symlink_data_len(u32 l)
+{
+	if (l < EXT4_CRYPTO_BLOCK_SIZE)
+		l = EXT4_CRYPTO_BLOCK_SIZE;
+	return (l + sizeof(struct ext4_encrypted_symlink_data) - 1);
+}
+
 #endif	/* _EXT4_CRYPTO_H */
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