validate classid

(Logical change 1.137)
diff --git a/tc/tc_util.c b/tc/tc_util.c
index 0dc76c0..a6413e6 100644
--- a/tc/tc_util.c
+++ b/tc/tc_util.c
@@ -61,11 +61,15 @@
 			return -1;
 	}
 	if (*p == ':') {
+		if (maj >= (1<<16))
+			return -1;
 		maj <<= 16;
 		str = p+1;
 		min = strtoul(str, &p, 16);
 		if (*p != 0)
 			return -1;
+		if (min >= (1<<16))
+			return -1;
 		maj |= min;
 	} else if (*p != 0)
 		return -1;