summaryrefslogtreecommitdiff
path: root/fs
diff options
context:
space:
mode:
authorJan Kara <jack@suse.cz>2014-10-30 10:52:57 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-11-14 08:59:58 -0800
commit43fa8712c4c552e59bf076a4dca37f6483d2c90d (patch)
tree75ce580d49f80a054d71cf1b3ba56a4c5c8f96c3 /fs
parent9cf666834cffdb450b9b18f3e06c30493cb40ed2 (diff)
downloadlwn-43fa8712c4c552e59bf076a4dca37f6483d2c90d.tar.gz
lwn-43fa8712c4c552e59bf076a4dca37f6483d2c90d.zip
ext4: fix overflow when updating superblock backups after resize
commit 9378c6768e4fca48971e7b6a9075bc006eda981d upstream. 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 Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
-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 14e0f8a25c81..2400ad1c3d12 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -1071,7 +1071,7 @@ static void update_backups(struct super_block *sb, int blk_off, char *data,
break;
if (meta_bg == 0)
- backup_block = group * bpg + blk_off;
+ backup_block = ((ext4_fsblk_t)group) * bpg + blk_off;
else
backup_block = (ext4_group_first_block_no(sb, group) +
ext4_bg_has_super(sb, group));