From: Florian Westphal <fw@strlen.de> stable inclusion from stable-v5.10.120 commit 91a36ec160ec1a0c8f5352b772dffcbb0b6023e3 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5L6BR Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit 56b14ecec97f39118bf85c9ac2438c5a949509ed upstream. In case the conntrack is clashing, insertion can free skb->_nfct and set skb->_nfct to the already-confirmed entry. This wasn't found before because the conntrack entry and the extension space used to free'd after an rcu grace period, plus the race needs events enabled to trigger. Reported-by: <syzbot+793a590957d9c1b96620@syzkaller.appspotmail.com> Fixes: 71d8c47fc653 ("netfilter: conntrack: introduce clash resolution on insertion race") Fixes: 2ad9d7747c10 ("netfilter: conntrack: free extension area immediately") Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> Acked-by: Xie XiuQi <xiexiuqi@huawei.com> --- include/net/netfilter/nf_conntrack_core.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/include/net/netfilter/nf_conntrack_core.h b/include/net/netfilter/nf_conntrack_core.h index 09f2efea0b97..5805fe4947f3 100644 --- a/include/net/netfilter/nf_conntrack_core.h +++ b/include/net/netfilter/nf_conntrack_core.h @@ -59,8 +59,13 @@ static inline int nf_conntrack_confirm(struct sk_buff *skb) int ret = NF_ACCEPT; if (ct) { - if (!nf_ct_is_confirmed(ct)) + if (!nf_ct_is_confirmed(ct)) { ret = __nf_conntrack_confirm(skb); + + if (ret == NF_ACCEPT) + ct = (struct nf_conn *)skb_nfct(skb); + } + if (likely(ret == NF_ACCEPT)) nf_ct_deliver_cached_events(ct); } -- 2.20.1