[PATCH 4.12 19/31] dm integrity: test for corrupted disk format during table load

Greg Kroah-Hartman
2017-08-03T23:23:58Z

From: Mikulas Patocka <mpatocka@redhat.com>

commit bc86a41e96c5b6f07453c405e036d95acc673389 upstream.

If the dm-integrity superblock was corrupted in such a way that the
journal_sections field was zero, the integrity target would deadlock
because it would wait forever for free space in the journal.

Detect this situation and refuse to activate the device.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: 7eada909bfd7 ("dm: add integrity target")
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/md/dm-integrity.c | 5 +++++
1 file changed, 5 insertions(+)

--- a/drivers/md/dm-integrity.c
+++ b/drivers/md/dm-integrity.c
@@ -3021,6 +3021,11 @@ static int dm_integrity_ctr(struct dm_ta
ti->error = "Block size doesn't match the information in superblock";
goto bad;
}
+ if (!le32_to_cpu(ic->sb->journal_sections)) {
+ r = -EINVAL;
+ ti->error = "Corrupted superblock, journal_sections is 0";
+ goto bad;
+ }
/* make sure that ti->max_io_len doesn't overflow */
if (ic->sb->log2_interleave_sectors < MIN_LOG2_INTERLEAVE_SECTORS ||
ic->sb->log2_interleave_sectors > MAX_LOG2_INTERLEAVE_SECTORS) {