[PATCH] net: sched: drr: dont intepret cls results when asked to drop

[Ma Ke]

If asked to drop a packet via TC_ACT_SHOT it is unsafe to
assume that res.class contains a valid pointer.

Signed-off-by: Ma Ke <make_ruc2021@xxxxxxx>
---
 net/sched/sch_drr.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/sched/sch_drr.c b/net/sched/sch_drr.c
index 19901e77cd3b..a535dc3b0e05 100644
--- a/net/sched/sch_drr.c
+++ b/net/sched/sch_drr.c
@@ -310,6 +310,8 @@ static struct drr_class *drr_classify(struct sk_buff *skb, struct Qdisc *sch,
 	fl = rcu_dereference_bh(q->filter_list);
 	result = tcf_classify(skb, NULL, fl, &res, false);
 	if (result >= 0) {
+		if (result == TC_ACT_SHOT)
+			return NULL;
 #ifdef CONFIG_NET_CLS_ACT
 		switch (result) {
 		case TC_ACT_QUEUED:
@@ -317,8 +319,6 @@ static struct drr_class *drr_classify(struct sk_buff *skb, struct Qdisc *sch,
 		case TC_ACT_TRAP:
 			*qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
 			fallthrough;
-		case TC_ACT_SHOT:
-			return NULL;
 		}
 #endif
 		cl = (struct drr_class *)res.class;
-- 
2.37.2