net/tap: check that user tries to define zero queues

Add check for queues parameter to be non-zero, and for fd/fds
parameters to be non-empty.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Signed-off-by: Jason Wang <jasowang@redhat.com>

net/tap.c

@@ -807,6 +807,10 @@ static int tap_parse_fds_and_queues(const NetdevTapOptions *tap, int **fds,
             error_setg(errp, "queues exceeds maximum %d", INT_MAX);
             return -1;
         }
+        if (tap->queues == 0) {
+            error_setg(errp, "queues must be greater than zero");
+            return -1;
+        }
         queues = tap->queues;
         *fds = NULL;
     } else if (tap->fd || tap->fds) {

net/util.c

@@ -94,6 +94,11 @@ int net_parse_fds(const char *fds_param, int **fds, int expected_nfds,
         return -1;
     }
 
+    if (nfds == 0) {
+        error_setg(errp, "no fds passed");
+        return -1;
+    }
+
     *fds = g_new(int, nfds);
 
     for (i = 0; i < nfds; i++) {