[NET_SCHED]: Fix prio/ingress classification logic error

Fix handling of empty or completely non-matching filter chains. In
that case -1 is returned and tcf_result is uninitialized, the
qdisc should fall back to default classification in that case.

Noticed by PJ Waskiewicz <peter.p.waskiewicz.jr@intel.com>.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 4 deletions

diff --git a/net/sched/sch_prio.c b/net/sched/sch_prio.c
index 2d8c08493d6e..71bafde353a6 100644
--- a/net/sched/sch_prio.c
+++ b/net/sched/sch_prio.c
@@ -38,9 +38,11 @@ prio_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
         struct prio_sched_data *q = qdisc_priv(sch);
         u32 band = skb->priority;
         struct tcf_result res;
+        int err;
 
         *qerr = NET_XMIT_BYPASS;
         if (TC_H_MAJ(skb->priority) != sch->handle) {
+                err = tc_classify(skb, q->filter_list, &res);
 #ifdef CONFIG_NET_CLS_ACT
                 switch (tc_classify(skb, q->filter_list, &res)) {
                 case TC_ACT_STOLEN:
@@ -49,11 +51,8 @@ prio_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr)
                 case TC_ACT_SHOT:
                         return NULL;
                 }
-
-                if (!q->filter_list ) {
-#else
-                if (!q->filter_list || tc_classify(skb, q->filter_list, &res)) {
 #endif
+                if (!q->filter_list || err < 0) {
                         if (TC_H_MAJ(band))
                                 band = 0;
                         band = q->prio2band[band&TC_PRIO_MAX];