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 044DF390221; Wed, 4 Mar 2026 11:49:53 +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=1772624994; cv=none; b=s4zrLxLAxCYc7WVgmiAxZLs0fMR8Ktp//HhOzdYnwHDJw0XH+WdnGo1QUQy1/Uab4HAPG8/DucUlIHZD6/Wm2RteXgeJ1MKfQEoSUcTDYsAxIc2gS3nUzASEvPlbru1bDI4DETDq6CsYLSQzPIw+QzHZpWNB959vboiA1HEyhN8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772624994; c=relaxed/simple; bh=rZ8BZk952ITWQ0BSpEdpYUFrqbQ6TyNIsRo07z0gcw8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=iTuE5mwy/dicW2i6gk2j5xV89GraOFRh2Uc86uyFqMzuDU4UkY4FnAdYSZMGNJxyoENxCXoN2OoSnWRPoyN6Q8mqsUaIeyHDk6GXwUroKtLR3oL8Pm1dJt1S82msg3rag/RKo+vM6hbhx4iEz6DqILGD3pr0CCU0ZI8MK0zB1ww= 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 C33D96026E; Wed, 04 Mar 2026 12:49:51 +0100 (CET) From: Florian Westphal To: Cc: Paolo Abeni , "David S. Miller" , Eric Dumazet , Jakub Kicinski , , pablo@netfilter.org Subject: [PATCH net-next 05/14] netfilter: xt_owner: no longer acquire sk_callback_lock in mt_owner() Date: Wed, 4 Mar 2026 12:49:12 +0100 Message-ID: <20260304114921.31042-6-fw@strlen.de> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260304114921.31042-1-fw@strlen.de> References: <20260304114921.31042-1-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: Eric Dumazet After commit 983512f3a87f ("net: Drop the lock in skb_may_tx_timestamp()") from Sebastian Andrzej Siewior, apply the same logic in mt_owner() to avoid touching sk_callback_lock. Signed-off-by: Eric Dumazet Signed-off-by: Florian Westphal --- net/netfilter/xt_owner.c | 28 ++++++++++++++-------------- 1 file changed, 14 insertions(+), 14 deletions(-) diff --git a/net/netfilter/xt_owner.c b/net/netfilter/xt_owner.c index 50332888c8d2..5bfb4843df66 100644 --- a/net/netfilter/xt_owner.c +++ b/net/netfilter/xt_owner.c @@ -63,11 +63,12 @@ static bool owner_mt(const struct sk_buff *skb, struct xt_action_param *par) { const struct xt_owner_match_info *info = par->matchinfo; - const struct file *filp; struct sock *sk = skb_to_full_sk(skb); struct net *net = xt_net(par); + const struct socket *sock; + const struct file *filp; - if (!sk || !sk->sk_socket || !net_eq(net, sock_net(sk))) + if (!sk || !READ_ONCE(sk->sk_socket) || !net_eq(net, sock_net(sk))) return (info->match ^ info->invert) == 0; else if (info->match & info->invert & XT_OWNER_SOCKET) /* @@ -76,23 +77,25 @@ owner_mt(const struct sk_buff *skb, struct xt_action_param *par) */ return false; - read_lock_bh(&sk->sk_callback_lock); - filp = sk->sk_socket ? sk->sk_socket->file : NULL; - if (filp == NULL) { - read_unlock_bh(&sk->sk_callback_lock); + /* The sk pointer remains valid as long as the skb is. The sk_socket and + * file pointer may become NULL if the socket is closed. Both structures + * (including file->cred) are RCU freed which means they can be accessed + * within a RCU read section. + */ + sock = READ_ONCE(sk->sk_socket); + filp = sock ? READ_ONCE(sock->file) : NULL; + if (filp == NULL) return ((info->match ^ info->invert) & (XT_OWNER_UID | XT_OWNER_GID)) == 0; - } if (info->match & XT_OWNER_UID) { kuid_t uid_min = make_kuid(net->user_ns, info->uid_min); kuid_t uid_max = make_kuid(net->user_ns, info->uid_max); + if ((uid_gte(filp->f_cred->fsuid, uid_min) && uid_lte(filp->f_cred->fsuid, uid_max)) ^ - !(info->invert & XT_OWNER_UID)) { - read_unlock_bh(&sk->sk_callback_lock); + !(info->invert & XT_OWNER_UID)) return false; - } } if (info->match & XT_OWNER_GID) { @@ -117,13 +120,10 @@ owner_mt(const struct sk_buff *skb, struct xt_action_param *par) } } - if (match ^ !(info->invert & XT_OWNER_GID)) { - read_unlock_bh(&sk->sk_callback_lock); + if (match ^ !(info->invert & XT_OWNER_GID)) return false; - } } - read_unlock_bh(&sk->sk_callback_lock); return true; } -- 2.52.0