Commit 56b14ece authored by Florian Westphal's avatar Florian Westphal Committed by Pablo Neira Ayuso

netfilter: conntrack: re-fetch conntrack after insertion

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: 71d8c47f ("netfilter: conntrack: introduce clash resolution on insertion race")
Fixes: 2ad9d774 ("netfilter: conntrack: free extension area immediately")
Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent ffd219ef
...@@ -58,8 +58,13 @@ static inline int nf_conntrack_confirm(struct sk_buff *skb) ...@@ -58,8 +58,13 @@ static inline int nf_conntrack_confirm(struct sk_buff *skb)
int ret = NF_ACCEPT; int ret = NF_ACCEPT;
if (ct) { if (ct) {
if (!nf_ct_is_confirmed(ct)) if (!nf_ct_is_confirmed(ct)) {
ret = __nf_conntrack_confirm(skb); ret = __nf_conntrack_confirm(skb);
if (ret == NF_ACCEPT)
ct = (struct nf_conn *)skb_nfct(skb);
}
if (ret == NF_ACCEPT && nf_ct_ecache_exist(ct)) if (ret == NF_ACCEPT && nf_ct_ecache_exist(ct))
nf_ct_deliver_cached_events(ct); nf_ct_deliver_cached_events(ct);
} }
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment