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| author | Mikulas Patocka <mpatocka@redhat.com> | 2021-05-10 14:49:05 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-05-26 11:27:32 +0200 |
| commit | 6353b35c47118474d86945e79edc4685f7bc8631 (patch) | |
| tree | 420c4ac642cb3c1dece209492bd6d6697722ed24 | |
| parent | 3e01c5c20452a385e70888cfb465e0359ffa54ad (diff) | |
| download | linux-stable-6353b35c47118474d86945e79edc4685f7bc8631.tar.gz linux-stable-6353b35c47118474d86945e79edc4685f7bc8631.tar.bz2 linux-stable-6353b35c47118474d86945e79edc4685f7bc8631.zip | |
dm snapshot: fix crash with transient storage and zero chunk size
commit c699a0db2d62e3bbb7f0bf35c87edbc8d23e3062 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 510b0cf430a8..2a1a7025b4b9 100644 --- a/drivers/md/dm-snap.c +++ b/drivers/md/dm-snap.c @@ -1265,6 +1265,7 @@ 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; } |