[PATCH 4.9 080/125] dm flakey: check for null arg_name in parse_features()

[Greg Kroah-Hartman]

From: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>

[ Upstream commit 7690e25302dc7d0cd42b349e746fe44b44a94f2b ]

One can crash dm-flakey by specifying more feature arguments than the
number of features supplied.  Checking for null in arg_name avoids
this.

dmsetup create flakey-test --table "0 66076080 flakey /dev/sdb9 0 0 180 2 drop_writes"

Signed-off-by: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/md/dm-flakey.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/md/dm-flakey.c b/drivers/md/dm-flakey.c
index 742c1fa870dae..36a98f4db0564 100644
--- a/drivers/md/dm-flakey.c
+++ b/drivers/md/dm-flakey.c
@@ -69,6 +69,11 @@ static int parse_features(struct dm_arg_set *as, struct flakey_c *fc,
 		arg_name = dm_shift_arg(as);
 		argc--;
 
+		if (!arg_name) {
+			ti->error = "Insufficient feature arguments";
+			return -EINVAL;
+		}
+
 		/*
 		 * drop_writes
 		 */
-- 
2.20.1