diff --git a/net/sched/act_ct.c b/net/sched/act_ct.c index 825b3e9b55f7e23900e55af586b45e826e1f5fbb..bcdaac703e0351d6f55800a32e0353a53eec3b90 100644 --- a/net/sched/act_ct.c +++ b/net/sched/act_ct.c @@ -1031,6 +1031,14 @@ static int tcf_ct_act(struct sk_buff *skb, const struct tc_action *a, */ if (nf_conntrack_confirm(skb) != NF_ACCEPT) goto drop; + + /* The ct may be dropped if a clash has been resolved, + * so it's necessary to retrieve it from skb again to + * prevent UAF. + */ + ct = nf_ct_get(skb, &ctinfo); + if (!ct) + skip_add = true; } if (!skip_add)