dm flakey: check for null arg_name in parse_features()

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@suse.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/md/dm-flakey.c b/drivers/md/dm-flakey.c
index b82cb1ab1eaa..1b907b15f5c3 100644
--- a/drivers/md/dm-flakey.c
+++ b/drivers/md/dm-flakey.c
@@ -70,6 +70,11 @@ 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
                  */