diff options
| author | Daeho Jeong <daeho.jeong@samsung.com> | 2016-07-04 00:51:39 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-09-15 09:27:51 +0300 |
| commit | 1d12bad745acfc02d452a13f32b4087865964c9a (patch) | |
| tree | 20712b46811823b8b761c2602db52b38c97a8cfc /fs/ext4/super.c | |
| parent | 77ae14d00650e7f7b2144019b855acbc6e27003f (diff) | |
| download | linux-1d12bad745acfc02d452a13f32b4087865964c9a.tar.xz | |
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/super.c')
| -rw-r--r-- | fs/ext4/super.c | 18 |
1 files changed, 9 insertions, 9 deletions
diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 60707c9ece36..5bab28caa9d4 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -2030,23 +2030,25 @@ failed: static __le16 ext4_group_desc_csum(struct super_block *sb, __u32 block_group, struct ext4_group_desc *gdp) { - int offset; + int offset = offsetof(struct ext4_group_desc, bg_checksum); __u16 crc = 0; __le32 le_group = cpu_to_le32(block_group); struct ext4_sb_info *sbi = EXT4_SB(sb); if (ext4_has_metadata_csum(sbi->s_sb)) { /* Use new metadata_csum algorithm */ - __le16 save_csum; __u32 csum32; + __u16 dummy_csum = 0; - save_csum = gdp->bg_checksum; - gdp->bg_checksum = 0; csum32 = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&le_group, sizeof(le_group)); - csum32 = ext4_chksum(sbi, csum32, (__u8 *)gdp, - sbi->s_desc_size); - gdp->bg_checksum = save_csum; + csum32 = ext4_chksum(sbi, csum32, (__u8 *)gdp, offset); + csum32 = ext4_chksum(sbi, csum32, (__u8 *)&dummy_csum, + sizeof(dummy_csum)); + offset += sizeof(dummy_csum); + if (offset < sbi->s_desc_size) + csum32 = ext4_chksum(sbi, csum32, (__u8 *)gdp + offset, + sbi->s_desc_size - offset); crc = csum32 & 0xFFFF; goto out; @@ -2056,8 +2058,6 @@ static __le16 ext4_group_desc_csum(struct super_block *sb, __u32 block_group, if (!ext4_has_feature_gdt_csum(sb)) return 0; - offset = offsetof(struct ext4_group_desc, bg_checksum); - crc = crc16(~0, sbi->s_es->s_uuid, sizeof(sbi->s_es->s_uuid)); crc = crc16(crc, (__u8 *)&le_group, sizeof(le_group)); crc = crc16(crc, (__u8 *)gdp, offset); |