diff options
| author | Daeho Jeong <daeho.jeong@samsung.com> | 2016-07-03 17:51:39 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-09-15 08:27:51 +0200 |
| commit | 1d12bad745acfc02d452a13f32b4087865964c9a (patch) | |
| tree | 20712b46811823b8b761c2602db52b38c97a8cfc /fs/ext4/xattr.c | |
| parent | 77ae14d00650e7f7b2144019b855acbc6e27003f (diff) | |
ext4: avoid modifying checksum fields directly during checksum verification
commit b47820edd1634dc1208f9212b7ecfb4230610a23 upstream.
We temporally change checksum fields in buffers of some types of
metadata into '0' for verifying the checksum values. By doing this
without locking the buffer, some metadata's checksums, which are
being committed or written back to the storage, could be damaged.
In our test, several metadata blocks were found with damaged metadata
checksum value during recovery process. When we only verify the
checksum value, we have to avoid modifying checksum fields directly.
Signed-off-by: Daeho Jeong <daeho.jeong@samsung.com>
Signed-off-by: Youngjin Gil <youngjin.gil@samsung.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Török Edwin <edwin@etorok.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/ext4/xattr.c')
| -rw-r--r-- | fs/ext4/xattr.c | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c index 02fd78cd2cd5..263002f0389d 100644 --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -123,17 +123,18 @@ static __le32 ext4_xattr_block_csum(struct inode *inode, { struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); __u32 csum; - __le32 save_csum; __le64 dsk_block_nr = cpu_to_le64(block_nr); + __u32 dummy_csum = 0; + int offset = offsetof(struct ext4_xattr_header, h_checksum); - save_csum = hdr->h_checksum; - hdr->h_checksum = 0; csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr, sizeof(dsk_block_nr)); - csum = ext4_chksum(sbi, csum, (__u8 *)hdr, - EXT4_BLOCK_SIZE(inode->i_sb)); + csum = ext4_chksum(sbi, csum, (__u8 *)hdr, offset); + csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum)); + offset += sizeof(dummy_csum); + csum = ext4_chksum(sbi, csum, (__u8 *)hdr + offset, + EXT4_BLOCK_SIZE(inode->i_sb) - offset); - hdr->h_checksum = save_csum; return cpu_to_le32(csum); } |