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authorJan Kara <jack@suse.cz>2014-10-30 10:52:57 -0400
committerTheodore Ts'o <tytso@mit.edu>2014-10-30 10:52:57 -0400
commit9378c6768e4fca48971e7b6a9075bc006eda981d (patch)
tree13d6696f82a1cb43c77172d5782fce31665bd40c /fs/ext4
parentcac7f2429872d3733dc3f9915857b1691da2eb2f (diff)
ext4: fix overflow when updating superblock backups after resize
When there are no meta block groups update_backups() will compute the backup block in 32-bit arithmetics thus possibly overflowing the block number and corrupting the filesystem. OTOH filesystems without meta block groups larger than 16 TB should be rare. Fix the problem by doing the counting in 64-bit arithmetics. Coverity-id: 741252 CC: stable@vger.kernel.org Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Lukas Czerner <lczerner@redhat.com>
Diffstat (limited to 'fs/ext4')
-rw-r--r--fs/ext4/resize.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index f298c60f907d..ca4588388fc3 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -1081,7 +1081,7 @@ static void update_backups(struct super_block *sb, int blk_off, char *data,
1081 break; 1081 break;
1082 1082
1083 if (meta_bg == 0) 1083 if (meta_bg == 0)
1084 backup_block = group * bpg + blk_off; 1084 backup_block = ((ext4_fsblk_t)group) * bpg + blk_off;
1085 else 1085 else
1086 backup_block = (ext4_group_first_block_no(sb, group) + 1086 backup_block = (ext4_group_first_block_no(sb, group) +
1087 ext4_bg_has_super(sb, group)); 1087 ext4_bg_has_super(sb, group));