From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 C88054C225E; Wed, 30 Sep 2026 18:10:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790791833; cv=none; b=eTfobcjhdxFPmxEGwLxZWYMv1alyCbuT5X2WIcGY4pU6kqpB2Vxg72VvKAVuIOotSUngJCgQ44jIiNiJgvH5cxJGDE0ZBiYqvd0lvXfohr9WIiG5ez3BKzL6bOqxcBBq2oP5DVRD3UtoW50XalI+GWkHHbNb91B9N0LO4GYmH5E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790791833; c=relaxed/simple; bh=HJ1WlOeNm3ocVmDn7v1QMNDBfoRblDKZPHbC7GMQ0/s=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PB5ElaM4/CjBFwUqOcGgmUtn3to/Y/lJ6t1z6KBw9beNUaykbBAyS9hzSy1qB+7IsV2/2kMFBknJk2Gi+m8vkskbtorDUYIfmcn2ItR0u/xnGRcDWPG2dIxuQ8s6aB7TnW3Bvf90q/k/tofxYdRu9BJHjcHE541icjT4IVWgPfM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=TfMc0qK9; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="TfMc0qK9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CAB171F000FF; Wed, 30 Sep 2026 18:10:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790791831; bh=bgQfPTA9TGFvWdSqykw2+30tTbhtXFxgwA8rez5jWAg=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=TfMc0qK9HDnIwI5LYdA7Y5wH9Y4FrgEtT0xrR2QI8Omn72QT3H1PerjWmI3Lszk7m /2J2J+zz7xeM9BrlnM++kWlejzqgjV6Wne3f029MoHDSQ43sRTEP/fAHdPuSPaRYj7 8CJ4sp1q0B0z9iO5wINH4eQdxQU6ILSlODo6vz6k= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sabrina Dubroca , Simon Horman , Steffen Klassert , Sasha Levin Subject: [PATCH 5.15 441/752] xfrm: avoid RCU warnings around the per-netns netlink socket Date: Wed, 30 Sep 2026 17:25:11 +0200 Message-ID: <20260930152407.826429830@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152358.131179731@linuxfoundation.org> References: <20260930152358.131179731@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sabrina Dubroca [ Upstream commit d87f8bc47fbf012a7f115e311d0603d97e47c34c ] net->xfrm.nlsk is used in 2 types of contexts: - fully under RCU, with rcu_read_lock + rcu_dereference and a NULL check - in the netlink handlers, with requests coming from a userspace socket In the 2nd case, net->xfrm.nlsk is guaranteed to stay non-NULL and the object is alive, since we can't enter the netns destruction path while the user socket holds a reference on the netns. After adding the __rcu annotation to netns_xfrm.nlsk (which silences sparse warnings in the RCU users and __net_init code), we need to tell sparse that the 2nd case is safe. Add a helper for that. Signed-off-by: Sabrina Dubroca Reviewed-by: Simon Horman Signed-off-by: Steffen Klassert Stable-dep-of: d1ebd9081879 ("xfrm: fix compat ALLOCSPI request use-after-free") Signed-off-by: Sasha Levin --- include/net/netns/xfrm.h | 2 +- net/xfrm/xfrm_user.c | 25 +++++++++++++++++-------- 2 files changed, 18 insertions(+), 9 deletions(-) diff --git a/include/net/netns/xfrm.h b/include/net/netns/xfrm.h index 423b52eca908d..7922ec72eaa68 100644 --- a/include/net/netns/xfrm.h +++ b/include/net/netns/xfrm.h @@ -59,7 +59,7 @@ struct netns_xfrm { struct list_head inexact_bins; - struct sock *nlsk; + struct sock __rcu *nlsk; struct sock *nlsk_stash; u32 sysctl_aevent_etime; diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c index 82578cb1933e6..677dfa40a7106 100644 --- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -34,6 +34,15 @@ #endif #include +static struct sock *xfrm_net_nlsk(const struct net *net, const struct sk_buff *skb) +{ + /* get the source of this request, see netlink_unicast_kernel */ + const struct sock *sk = NETLINK_CB(skb).sk; + + /* sk is refcounted, the netns stays alive and nlsk with it */ + return rcu_dereference_protected(net->xfrm.nlsk, sk->sk_net_refcnt); +} + static int verify_one_alg(struct nlattr **attrs, enum xfrm_attr_type_t type, struct netlink_ext_ack *extack) { @@ -1427,7 +1436,7 @@ static int xfrm_get_spdinfo(struct sk_buff *skb, struct nlmsghdr *nlh, err = build_spdinfo(r_skb, net, sportid, seq, *flags); BUG_ON(err < 0); - return nlmsg_unicast(net->xfrm.nlsk, r_skb, sportid); + return nlmsg_unicast(xfrm_net_nlsk(net, skb), r_skb, sportid); } static inline unsigned int xfrm_sadinfo_msgsize(void) @@ -1487,7 +1496,7 @@ static int xfrm_get_sadinfo(struct sk_buff *skb, struct nlmsghdr *nlh, err = build_sadinfo(r_skb, net, sportid, seq, *flags); BUG_ON(err < 0); - return nlmsg_unicast(net->xfrm.nlsk, r_skb, sportid); + return nlmsg_unicast(xfrm_net_nlsk(net, skb), r_skb, sportid); } static int xfrm_get_sa(struct sk_buff *skb, struct nlmsghdr *nlh, @@ -1507,7 +1516,7 @@ static int xfrm_get_sa(struct sk_buff *skb, struct nlmsghdr *nlh, if (IS_ERR(resp_skb)) { err = PTR_ERR(resp_skb); } else { - err = nlmsg_unicast(net->xfrm.nlsk, resp_skb, NETLINK_CB(skb).portid); + err = nlmsg_unicast(xfrm_net_nlsk(net, skb), resp_skb, NETLINK_CB(skb).portid); } xfrm_state_put(x); out_noput: @@ -1583,7 +1592,7 @@ static int xfrm_alloc_userspi(struct sk_buff *skb, struct nlmsghdr *nlh, } } - err = nlmsg_unicast(net->xfrm.nlsk, resp_skb, NETLINK_CB(skb).portid); + err = nlmsg_unicast(xfrm_net_nlsk(net, skb), resp_skb, NETLINK_CB(skb).portid); out: xfrm_state_put(x); @@ -2180,7 +2189,7 @@ static int xfrm_get_default(struct sk_buff *skb, struct nlmsghdr *nlh, r_up->out = net->xfrm.policy_default[XFRM_POLICY_OUT]; nlmsg_end(r_skb, r_nlh); - return nlmsg_unicast(net->xfrm.nlsk, r_skb, portid); + return nlmsg_unicast(xfrm_net_nlsk(net, skb), r_skb, portid); } static int xfrm_get_policy(struct sk_buff *skb, struct nlmsghdr *nlh, @@ -2246,7 +2255,7 @@ static int xfrm_get_policy(struct sk_buff *skb, struct nlmsghdr *nlh, if (IS_ERR(resp_skb)) { err = PTR_ERR(resp_skb); } else { - err = nlmsg_unicast(net->xfrm.nlsk, resp_skb, + err = nlmsg_unicast(xfrm_net_nlsk(net, skb), resp_skb, NETLINK_CB(skb).portid); } } else { @@ -2406,7 +2415,7 @@ static int xfrm_get_ae(struct sk_buff *skb, struct nlmsghdr *nlh, err = build_aevent(r_skb, x, &c); BUG_ON(err < 0); - err = nlmsg_unicast(net->xfrm.nlsk, r_skb, NETLINK_CB(skb).portid); + err = nlmsg_unicast(xfrm_net_nlsk(net, skb), r_skb, NETLINK_CB(skb).portid); spin_unlock_bh(&x->lock); xfrm_state_put(x); return err; @@ -3032,7 +3041,7 @@ static int xfrm_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, goto err; } - err = netlink_dump_start(net->xfrm.nlsk, skb, nlh, &c); + err = netlink_dump_start(xfrm_net_nlsk(net, skb), skb, nlh, &c); goto err; } -- 2.53.0