[v1] net: sched: qfq: dont intepret cls results when asked to drop

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

Posted by Ma Ke 2 years, 4 months ago

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@163.com>
---
 net/sched/sch_qfq.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/sched/sch_qfq.c b/net/sched/sch_qfq.c
index 546c10adcacd..20d52dc484b6 100644
--- a/net/sched/sch_qfq.c
+++ b/net/sched/sch_qfq.c
@@ -695,6 +695,8 @@ static struct qfq_class *qfq_classify(struct sk_buff *skb, struct Qdisc *sch,
 	*qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
 	fl = rcu_dereference_bh(q->filter_list);
 	result = tcf_classify(skb, NULL, fl, &res, false);
+	if (result == TC_ACT_SHOT)
+		return NULL;
 	if (result >= 0) {
 #ifdef CONFIG_NET_CLS_ACT
 		switch (result) {
-- 
2.37.2

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

Posted by Eric Dumazet 2 years, 4 months ago

On Fri, Sep 15, 2023 at 1:08 PM Ma Ke <make_ruc2021@163.com> wrote:
>
> 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@163.com>
> ---
>  net/sched/sch_qfq.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/net/sched/sch_qfq.c b/net/sched/sch_qfq.c
> index 546c10adcacd..20d52dc484b6 100644
> --- a/net/sched/sch_qfq.c
> +++ b/net/sched/sch_qfq.c
> @@ -695,6 +695,8 @@ static struct qfq_class *qfq_classify(struct sk_buff *skb, struct Qdisc *sch,
>         *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
>         fl = rcu_dereference_bh(q->filter_list);
>         result = tcf_classify(skb, NULL, fl, &res, false);
> +       if (result == TC_ACT_SHOT)
> +               return NULL;
>         if (result >= 0) {
>  #ifdef CONFIG_NET_CLS_ACT
>                 switch (result) {
> --
> 2.37.2
>

Same comment, it seems already handled at line 706