--- /n/sources/plan9/sys/src/9/ip/iproute.c	Thu Feb  7 14:55:43 2013
+++ /sys/src/9/ip/iproute.c	Thu May  5 00:00:00 2016
@@ -824,6 +824,9 @@
 		nexterror();
 	}
 
+	if(cb->nf < 1)
+		error("short control request");
+
 	if(strcmp(cb->f[0], "flush") == 0){
 		tag = cb->f[1];
 		for(h = 0; h < nelem(f->v4root); h++)
@@ -884,7 +887,8 @@
 			print("no route\n");
 		else
 			printroute(q);
-	}
+	} else
+		error(Ebadctl);
 
 	poperror();
 	free(cb);