net_sched: qdisc_get_rtab() must check data[] array

qdisc_get_rtab() should check not only the keys in struct tc_ratespec,
but also the full data[] array.

"tc ... linklayer atm " only perturbs values in the 256 slots array.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/sched/sch_api.c

@@ -291,17 +291,18 @@ struct qdisc_rate_table *qdisc_get_rtab(struct tc_ratespec *r, struct nlattr *ta
 {
 	struct qdisc_rate_table *rtab;
 
+	if (tab == NULL || r->rate == 0 || r->cell_log == 0 ||
+	    nla_len(tab) != TC_RTAB_SIZE)
+		return NULL;
+
 	for (rtab = qdisc_rtab_list; rtab; rtab = rtab->next) {
-		if (memcmp(&rtab->rate, r, sizeof(struct tc_ratespec)) == 0) {
+		if (!memcmp(&rtab->rate, r, sizeof(struct tc_ratespec)) &&
+		    !memcmp(&rtab->data, nla_data(tab), 1024)) {
 			rtab->refcnt++;
 			return rtab;
 		}
 	}
 
-	if (tab == NULL || r->rate == 0 || r->cell_log == 0 ||
-	    nla_len(tab) != TC_RTAB_SIZE)
-		return NULL;
-
 	rtab = kmalloc(sizeof(*rtab), GFP_KERNEL);
 	if (rtab) {
 		rtab->rate = *r;