dm flakey: fix a crash with invalid table line

commit 98dba02d9a93eec11bffbb93c7c51624290702d2 upstream.

This command will crash with NULL pointer dereference:
 dmsetup create flakey --table \
  "0 `blockdev --getsize /dev/ram0` flakey /dev/ram0 0 0 1 2 corrupt_bio_byte 512"

Fix the crash by checking if arg_name is non-NULL before comparing it.

Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Mikulas Patocka 2023-04-18 15:57:47 -04:00 committed by Greg Kroah-Hartman
parent ca8b634fdf
commit 12849ed107

View file

@ -124,9 +124,9 @@ static int parse_features(struct dm_arg_set *as, struct flakey_c *fc,
* Direction r or w?
*/
arg_name = dm_shift_arg(as);
if (!strcasecmp(arg_name, "w"))
if (arg_name && !strcasecmp(arg_name, "w"))
fc->corrupt_bio_rw = WRITE;
else if (!strcasecmp(arg_name, "r"))
else if (arg_name && !strcasecmp(arg_name, "r"))
fc->corrupt_bio_rw = READ;
else {
ti->error = "Invalid corrupt bio direction (r or w)";