dm mpath: fix potential NULL pointer in feature arg processing

Avoid dereferencing a NULL pointer if the number of feature arguments
supplied is fewer than indicated.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Cc: stable@kernel.org

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index c3547016f0f1e7156d1b28b0fded62b5bf534008..adf851a081bd512f1a12fed3df76cfde6acec975 100644 (file)
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -807,6 +807,11 @@ static int parse_features(struct arg_set *as, struct multipath *m)
        if (!argc)
                return 0;
 
+       if (argc > as->argc) {
+               ti->error = "not enough arguments for features";
+               return -EINVAL;
+       }
+
        do {
                param_name = shift(as);
                argc--;