dm mpath: validate hw_handler argument count

Fix arg count parsing error in hw handlers.

Cc: stable@kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index d880299334e9..f25bdebcb4ab 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -705,6 +705,11 @@ static int parse_hw_handler(struct arg_set *as, struct multipath *m)
         if (!hw_argc)
                 return 0;
 
+        if (hw_argc > as->argc) {
+                ti->error = "not enough arguments for hardware handler";
+                return -EINVAL;
+        }
+
         m->hw_handler_name = kstrdup(shift(as), GFP_KERNEL);
         request_module("scsi_dh_%s", m->hw_handler_name);
         if (scsi_dh_handler_exist(m->hw_handler_name) == 0) {