[PATCH 5.15.y 2/5] netfilter: remove nf_ct_unconfirmed_destroy helper

[Sasha Levin <sashal@kernel.org>]

From: Florian Westphal <fw@strlen.de>

[ Upstream commit 17438b42ce14cb60ceda9ae62ad5dd022d55a216 ]

This helper tags connections not yet in the conntrack table as
dying.  These nf_conn entries will be dropped instead when the
core attempts to insert them from the input or postrouting
'confirm' hook.

After the previous change, the entries get unlinked from the
list earlier, so that by the time the actual exit hook runs,
new connections no longer have a timeout policy assigned.

Its enough to walk the hashtable instead.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Stable-dep-of: fec9b1de0d02 ("netfilter: cttimeout: prevent UAF during module unload")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/net/netfilter/nf_conntrack.h |  3 ---
 net/netfilter/nf_conntrack_core.c    | 14 --------------
 net/netfilter/nfnetlink_cttimeout.c  |  4 +++-
 3 files changed, 3 insertions(+), 18 deletions(-)

diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h
index 39541ab912a16..571f44a2a6fed 100644
--- a/include/net/netfilter/nf_conntrack.h
+++ b/include/net/netfilter/nf_conntrack.h
@@ -240,9 +240,6 @@ static inline bool nf_ct_kill(struct nf_conn *ct)
 	return nf_ct_delete(ct, 0, 0);
 }
 
-/* Set all unconfirmed conntrack as dying */
-void nf_ct_unconfirmed_destroy(struct net *);
-
 /* Iterate over all conntracks: if iter returns true, it's deleted. */
 void nf_ct_iterate_cleanup_net(struct net *net,
 			       int (*iter)(struct nf_conn *i, void *data),
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index ea9aba75b38af..65fea9f685260 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -2446,20 +2446,6 @@ __nf_ct_unconfirmed_destroy(struct net *net)
 	}
 }
 
-void nf_ct_unconfirmed_destroy(struct net *net)
-{
-	struct nf_conntrack_net *cnet = nf_ct_pernet(net);
-
-	might_sleep();
-
-	if (atomic_read(&cnet->count) > 0) {
-		__nf_ct_unconfirmed_destroy(net);
-		nf_queue_nf_hook_drop(net);
-		synchronize_net();
-	}
-}
-EXPORT_SYMBOL_GPL(nf_ct_unconfirmed_destroy);
-
 void nf_ct_iterate_cleanup_net(struct net *net,
 			       int (*iter)(struct nf_conn *i, void *data),
 			       void *data, u32 portid, int report)
diff --git a/net/netfilter/nfnetlink_cttimeout.c b/net/netfilter/nfnetlink_cttimeout.c
index 2a241ed20edd2..e2baa56fde531 100644
--- a/net/netfilter/nfnetlink_cttimeout.c
+++ b/net/netfilter/nfnetlink_cttimeout.c
@@ -612,7 +612,9 @@ static void __net_exit cttimeout_net_exit(struct net *net)
 	struct nfct_timeout_pernet *pernet = nfct_timeout_pernet(net);
 	struct ctnl_timeout *cur, *tmp;
 
-	nf_ct_unconfirmed_destroy(net);
+	if (list_empty(&pernet->nfct_timeout_freelist))
+		return;
+
 	nf_ct_untimeout(net, NULL);
 
 	list_for_each_entry_safe(cur, tmp, &pernet->nfct_timeout_freelist, head) {
-- 
2.53.0