From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [91.216.245.30]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BF6603D9DAE; Wed, 25 Mar 2026 13:12:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.216.245.30 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774444331; cv=none; b=FbOmM970oR55eyO42iG1d0dB8dJSPby9XjvBSFmPP3V4cAjxhdQOBQOwFiJUv54RywTr1YjwH9OZMRGcsKcmpxDp4TjL2ES7hfXjVak8nE9o52B6SQJ4+rhTw3GmgAg61xjtJBIhuhby6EqMNye7+xD5lFu25A81t0+KxUxIE5c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774444331; c=relaxed/simple; bh=QPx8aZ4EIRNRk3EuhjhbxwWFUz1O04BIedHDikjetes=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=LiV0wM+KR5eh/7sfskjg8QZkiFyDeMt9j6gRQISdOy9ndn5ITwDMYqD4ctZFIPWLM8u1NuCYvOHR+uEagh+CvXEj8zdeWIAjADAjATRaQFQEkXVifYSEyZho24LLozRboUGe7gxyD5jKn2YAkNqQimvsXK60Y3EQKaaI5Fg5Cxk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=strlen.de; spf=pass smtp.mailfrom=Chamillionaire.breakpoint.cc; arc=none smtp.client-ip=91.216.245.30 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=strlen.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=Chamillionaire.breakpoint.cc Received: by Chamillionaire.breakpoint.cc (Postfix, from userid 1003) id 3EA706080C; Wed, 25 Mar 2026 14:12:08 +0100 (CET) From: Florian Westphal To: Cc: Paolo Abeni , "David S. Miller" , Eric Dumazet , Jakub Kicinski , , pablo@netfilter.org Subject: [PATCH net 08/14] netfilter: nf_conntrack_expect: honor expectation helper field Date: Wed, 25 Mar 2026 14:11:02 +0100 Message-ID: <20260325131108.23045-9-fw@strlen.de> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260325131108.23045-1-fw@strlen.de> References: <20260325131108.23045-1-fw@strlen.de> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Pablo Neira Ayuso The expectation helper field is mostly unused. As a result, the netfilter codebase relies on accessing the helper through exp->master. Always set on the expectation helper field so it can be used to reach the helper. This is a preparation patches for follow up fixes. Signed-off-by: Pablo Neira Ayuso Signed-off-by: Florian Westphal --- include/net/netfilter/nf_conntrack_expect.h | 2 +- net/netfilter/nf_conntrack_broadcast.c | 2 +- net/netfilter/nf_conntrack_expect.c | 6 +++++- net/netfilter/nf_conntrack_h323_main.c | 12 ++++++------ net/netfilter/nf_conntrack_helper.c | 7 ++++++- net/netfilter/nf_conntrack_netlink.c | 2 +- net/netfilter/nf_conntrack_sip.c | 2 +- 7 files changed, 21 insertions(+), 12 deletions(-) diff --git a/include/net/netfilter/nf_conntrack_expect.h b/include/net/netfilter/nf_conntrack_expect.h index 165e7a03b8e9..1b01400b10bd 100644 --- a/include/net/netfilter/nf_conntrack_expect.h +++ b/include/net/netfilter/nf_conntrack_expect.h @@ -40,7 +40,7 @@ struct nf_conntrack_expect { struct nf_conntrack_expect *this); /* Helper to assign to new connection */ - struct nf_conntrack_helper *helper; + struct nf_conntrack_helper __rcu *helper; /* The conntrack of the master connection */ struct nf_conn *master; diff --git a/net/netfilter/nf_conntrack_broadcast.c b/net/netfilter/nf_conntrack_broadcast.c index a7552a46d6ac..d21576fcb1d6 100644 --- a/net/netfilter/nf_conntrack_broadcast.c +++ b/net/netfilter/nf_conntrack_broadcast.c @@ -70,7 +70,7 @@ int nf_conntrack_broadcast_help(struct sk_buff *skb, exp->expectfn = NULL; exp->flags = NF_CT_EXPECT_PERMANENT; exp->class = NF_CT_EXPECT_CLASS_DEFAULT; - exp->helper = NULL; + rcu_assign_pointer(exp->helper, nfct_help(ct)->helper); nf_ct_expect_related(exp, 0); nf_ct_expect_put(exp); diff --git a/net/netfilter/nf_conntrack_expect.c b/net/netfilter/nf_conntrack_expect.c index cfc2daa3fc7f..197a76d0b231 100644 --- a/net/netfilter/nf_conntrack_expect.c +++ b/net/netfilter/nf_conntrack_expect.c @@ -309,6 +309,10 @@ struct nf_conntrack_expect *nf_ct_expect_alloc(struct nf_conn *me) } EXPORT_SYMBOL_GPL(nf_ct_expect_alloc); +/* This function can only be used from packet path, where accessing + * master's helper is safe, because the packet holds a reference on + * the conntrack object. Never use it from control plane. + */ void nf_ct_expect_init(struct nf_conntrack_expect *exp, unsigned int class, u_int8_t family, const union nf_inet_addr *saddr, @@ -325,7 +329,7 @@ void nf_ct_expect_init(struct nf_conntrack_expect *exp, unsigned int class, exp->flags = 0; exp->class = class; exp->expectfn = NULL; - exp->helper = NULL; + rcu_assign_pointer(exp->helper, nfct_help(exp->master)->helper); exp->tuple.src.l3num = family; exp->tuple.dst.protonum = proto; diff --git a/net/netfilter/nf_conntrack_h323_main.c b/net/netfilter/nf_conntrack_h323_main.c index a2a0e22ccee1..3f5c50455b71 100644 --- a/net/netfilter/nf_conntrack_h323_main.c +++ b/net/netfilter/nf_conntrack_h323_main.c @@ -643,7 +643,7 @@ static int expect_h245(struct sk_buff *skb, struct nf_conn *ct, &ct->tuplehash[!dir].tuple.src.u3, &ct->tuplehash[!dir].tuple.dst.u3, IPPROTO_TCP, NULL, &port); - exp->helper = &nf_conntrack_helper_h245; + rcu_assign_pointer(exp->helper, &nf_conntrack_helper_h245); nathook = rcu_dereference(nfct_h323_nat_hook); if (memcmp(&ct->tuplehash[dir].tuple.src.u3, @@ -767,7 +767,7 @@ static int expect_callforwarding(struct sk_buff *skb, nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, nf_ct_l3num(ct), &ct->tuplehash[!dir].tuple.src.u3, &addr, IPPROTO_TCP, NULL, &port); - exp->helper = nf_conntrack_helper_q931; + rcu_assign_pointer(exp->helper, nf_conntrack_helper_q931); nathook = rcu_dereference(nfct_h323_nat_hook); if (memcmp(&ct->tuplehash[dir].tuple.src.u3, @@ -1234,7 +1234,7 @@ static int expect_q931(struct sk_buff *skb, struct nf_conn *ct, &ct->tuplehash[!dir].tuple.src.u3 : NULL, &ct->tuplehash[!dir].tuple.dst.u3, IPPROTO_TCP, NULL, &port); - exp->helper = nf_conntrack_helper_q931; + rcu_assign_pointer(exp->helper, nf_conntrack_helper_q931); exp->flags = NF_CT_EXPECT_PERMANENT; /* Accept multiple calls */ nathook = rcu_dereference(nfct_h323_nat_hook); @@ -1306,7 +1306,7 @@ static int process_gcf(struct sk_buff *skb, struct nf_conn *ct, nf_ct_expect_init(exp, NF_CT_EXPECT_CLASS_DEFAULT, nf_ct_l3num(ct), &ct->tuplehash[!dir].tuple.src.u3, &addr, IPPROTO_UDP, NULL, &port); - exp->helper = nf_conntrack_helper_ras; + rcu_assign_pointer(exp->helper, nf_conntrack_helper_ras); if (nf_ct_expect_related(exp, 0) == 0) { pr_debug("nf_ct_ras: expect RAS "); @@ -1523,7 +1523,7 @@ static int process_acf(struct sk_buff *skb, struct nf_conn *ct, &ct->tuplehash[!dir].tuple.src.u3, &addr, IPPROTO_TCP, NULL, &port); exp->flags = NF_CT_EXPECT_PERMANENT; - exp->helper = nf_conntrack_helper_q931; + rcu_assign_pointer(exp->helper, nf_conntrack_helper_q931); if (nf_ct_expect_related(exp, 0) == 0) { pr_debug("nf_ct_ras: expect Q.931 "); @@ -1577,7 +1577,7 @@ static int process_lcf(struct sk_buff *skb, struct nf_conn *ct, &ct->tuplehash[!dir].tuple.src.u3, &addr, IPPROTO_TCP, NULL, &port); exp->flags = NF_CT_EXPECT_PERMANENT; - exp->helper = nf_conntrack_helper_q931; + rcu_assign_pointer(exp->helper, nf_conntrack_helper_q931); if (nf_ct_expect_related(exp, 0) == 0) { pr_debug("nf_ct_ras: expect Q.931 "); diff --git a/net/netfilter/nf_conntrack_helper.c b/net/netfilter/nf_conntrack_helper.c index ceb48c3ca0a4..294a6ffcbccd 100644 --- a/net/netfilter/nf_conntrack_helper.c +++ b/net/netfilter/nf_conntrack_helper.c @@ -399,7 +399,7 @@ static bool expect_iter_me(struct nf_conntrack_expect *exp, void *data) const struct nf_conntrack_helper *me = data; const struct nf_conntrack_helper *this; - if (exp->helper == me) + if (rcu_access_pointer(exp->helper) == me) return true; this = rcu_dereference_protected(help->helper, @@ -421,6 +421,11 @@ void nf_conntrack_helper_unregister(struct nf_conntrack_helper *me) nf_ct_expect_iterate_destroy(expect_iter_me, NULL); nf_ct_iterate_destroy(unhelp, me); + + /* nf_ct_iterate_destroy() does an unconditional synchronize_rcu() as + * last step, this ensures rcu readers of exp->helper are done. + * No need for another synchronize_rcu() here. + */ } EXPORT_SYMBOL_GPL(nf_conntrack_helper_unregister); diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index c156574e1273..a42d14290786 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -3573,7 +3573,7 @@ ctnetlink_alloc_expect(const struct nlattr * const cda[], struct nf_conn *ct, exp->class = class; exp->master = ct; - exp->helper = helper; + rcu_assign_pointer(exp->helper, helper); exp->tuple = *tuple; exp->mask.src.u3 = mask->src.u3; exp->mask.src.u.all = mask->src.u.all; diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c index 4ab5ef71d96d..106b2f419e19 100644 --- a/net/netfilter/nf_conntrack_sip.c +++ b/net/netfilter/nf_conntrack_sip.c @@ -1297,7 +1297,7 @@ static int process_register_request(struct sk_buff *skb, unsigned int protoff, nf_ct_expect_init(exp, SIP_EXPECT_SIGNALLING, nf_ct_l3num(ct), saddr, &daddr, proto, NULL, &port); exp->timeout.expires = sip_timeout * HZ; - exp->helper = helper; + rcu_assign_pointer(exp->helper, helper); exp->flags = NF_CT_EXPECT_PERMANENT | NF_CT_EXPECT_INACTIVE; hooks = rcu_dereference(nf_nat_sip_hooks); -- 2.52.0