linux-ext4 - [PATCH 03/10] e2fsck: fix reading fscrypt_symlink

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Date:   Fri,  2 Mar 2018 16:59:16 -0800
From:   Eric Biggers <ebiggers3@...il.com>
To:     linux-ext4@...r.kernel.org
Cc:     Eric Biggers <ebiggers@...gle.com>
Subject: [PATCH 03/10] e2fsck: fix reading fscrypt_symlink_data.len

From: Eric Biggers <ebiggers@...gle.com>

The ciphertext length field stored at the beginning of encrypted symlink
targets is 16-bit.  But e2fsck_pass1_check_symlink() is reading it as
32-bit.  This was apparently left over from an earlier on-disk format
that was not merged.  Fix it.

This bug caused a small proportion of encrypted symlinks with 4092-byte
targets to be considered invalid by e2fsck, but otherwise had no effect.

Fixes: 62ad24802c6e ("e2fsck: handle encrypted directories which are indexed using htree")
Signed-off-by: Eric Biggers <ebiggers@...gle.com>
---
 e2fsck/pass1.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/e2fsck/pass1.c b/e2fsck/pass1.c
index 5015d938..b101df0a 100644
--- a/e2fsck/pass1.c
+++ b/e2fsck/pass1.c
@@ -249,7 +249,7 @@ int e2fsck_pass1_check_symlink(ext2_filsys fs, ext2_ino_t ino,
 			return 0;
 
 		if (inode->i_flags & EXT4_ENCRYPT_FL) {
-			len = ext2fs_le32_to_cpu(*((__u32 *)buf)) + 4;
+			len = ext2fs_le16_to_cpu(*((__u16 *)buf)) + 2;
 		} else {
 			len = strnlen(buf, fs->blocksize);
 		}
-- 
2.16.2.395.g2e18187dfd-goog