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| author | Mikulas Patocka <mpatocka@redhat.com> | 2021-05-10 21:49:05 +0300 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2021-05-13 21:42:52 +0300 |
| commit | c699a0db2d62e3bbb7f0bf35c87edbc8d23e3062 (patch) | |
| tree | 22dff394ba42ecd8141bbd8ff8b6482df8de99e9 /drivers/md/dm-snap.c | |
| parent | 7ee06ddc4038f936b0d4459d37a7d4d844fb03db (diff) | |
| download | linux-c699a0db2d62e3bbb7f0bf35c87edbc8d23e3062.tar.xz | |
dm snapshot: fix crash with transient storage and zero chunk size
The following commands will crash the kernel:
modprobe brd rd_size=1048576
dmsetup create o --table "0 `blockdev --getsize /dev/ram0` snapshot-origin /dev/ram0"
dmsetup create s --table "0 `blockdev --getsize /dev/ram0` snapshot /dev/ram0 /dev/ram1 N 0"
The reason is that when we test for zero chunk size, we jump to the label
bad_read_metadata without setting the "r" variable. The function
snapshot_ctr destroys all the structures and then exits with "r == 0". The
kernel then crashes because it falsely believes that snapshot_ctr
succeeded.
In order to fix the bug, we set the variable "r" to -EINVAL.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm-snap.c')
| -rw-r--r-- | drivers/md/dm-snap.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/md/dm-snap.c b/drivers/md/dm-snap.c index 2a51ddd840b4..b8e4d31124ea 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -1408,6 +1408,7 @@ static int snapshot_ctr(struct dm_target *ti, unsigned int argc, char **argv) if (!s->store->chunk_size) { ti->error = "Chunk size not set"; + r = -EINVAL; goto bad_read_metadata; } |