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 DCCF43644B3 for ; Thu, 17 Sep 2026 01:13:24 +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=1789607607; cv=none; b=RbyTxkCUS+hQ2QtgTZ4XeSpx+1eVGW6qDlEXE8rNE8EIpLCzQ9Lr0ZpZlK/8d+Rg84nvZSTsB1P8zbk1GY8DR6XXoYkZx0+cRd83KswrJFcHAKlky7UNzMUyg/3quIEMyCxjUdYpx5Lf3s3s1fm/YKYa42EDfIs5wLqRKzMi2j4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789607607; c=relaxed/simple; bh=OcbcXIIH3ynNM9UVN9tH1sfJLUj5V7wQUeCIpRDMRXs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=OnRvFVBAZiYyCkGWw2jOy34JE1ZdlKoplqe8Mzhc6TQxklpaAdS//NGYEpDhyK30WoH5GOScvQur8NSFbi0m5fWs92GIjXbH5aa1AHV+qL0MpXdydPWAzpoq6DnDG60UwLbwwfyXXvXhCwe6BhSjN7aJPohGq0fYIggyTwx1+/Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HidDjegL; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="HidDjegL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4A4301F0089B; Thu, 17 Sep 2026 01:13:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789607602; bh=2jIrXc/UPfexJFOQXnwlgHsDqxmWyLCT5nR7OszkQX4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=HidDjegLcJbTuy/Tib/JkaFyEqbcRA+UiCaRIyrDQaA3x84goV2eyr/lJ69hMx2PZ IRGRMGeSdc6R2rR3/0CDlv4HFcX9VJSkbeHKx8ubl4iNAjvHUioRhJXjINVsEVdM2t lNEaOnsKGVyFUwIw/4GBU0yPhHFw57BQh5Bg5x1mb1hElZCLVLWc3MEDEf2Uz89IOz v2pcnL33rGpzmylS+NcWxIHoRzOsBSIBEWdasD/kW92y+59AzlYUbWYHY2g0xhUISb kChObi6GOWmxFXlRYVHfPLst6VpPNGnUvon5kIv+i3KQykr3HcSFYmYA2N10CMoV+X Dw1HTu0CJdZQw== From: Sasha Levin To: stable@vger.kernel.org Cc: Chengfeng Ye , Pablo Neira Ayuso , Sasha Levin Subject: [PATCH 5.10.y 4/4] netfilter: nf_log: unregister loggers before per-net teardown Date: Wed, 16 Sep 2026 21:13:18 -0400 Message-ID: <20260917011318.3530857-4-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260917011318.3530857-1-sashal@kernel.org> References: <2026091608-unstaffed-playpen-7696@gregkh> <20260917011318.3530857-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Chengfeng Ye [ Upstream commit 2c018cc4842c33f0c732962e2ab58635e8ae5823 ] nf_log_syslog and nfnetlink_log unregister their per-network namespace operations before unregistering their global logger backends. This leaves a window where a sysctl or netlink writer can rebind the still- registered logger after the per-net pre-exit callback cleared the old selection. The race looks like this: CPU 0 CPU 1 ---- ---- unregister_pernet_subsys() nf_log_unset(net, logger) net->nf.nf_loggers[pf] = NULL lock nf_log_mutex find logger in loggers[][] net->nf.nf_loggers[pf] = logger unlock nf_log_mutex nf_log_unregister(logger) lock nf_log_mutex loggers[pf][type] = NULL unlock nf_log_mutex synchronize_rcu() module exit returns module core frees backend memory Later, a sysctl read or packet logging operation can dereference the stale per-net logger pointer. Fix this by unregistering the global logger backends before tearing down per-net state. Once the global registrations are gone, later writers can no longer rebind the logger. unregister_pernet_subsys() already waits for an RCU grace period after the pre-exit callback clears the per-net selection, while nf_log_unregister() continues to cover readers of the global logger table. Apply this ordering fix to both nf_log backends that combine per-net teardown with global logger registration. Fixes: 5b023fc8d8e0 ("netfilter: enable per netns support for nf_loggers") Cc: stable@vger.kernel.org Signed-off-by: Chengfeng Ye Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin --- net/netfilter/nf_log_syslog.c | 2 +- net/netfilter/nfnetlink_log.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/net/netfilter/nf_log_syslog.c b/net/netfilter/nf_log_syslog.c index cce8f282b0eda..bf902b1fe2aac 100644 --- a/net/netfilter/nf_log_syslog.c +++ b/net/netfilter/nf_log_syslog.c @@ -899,12 +899,12 @@ static int __init nf_log_syslog_init(void) static void __exit nf_log_syslog_exit(void) { - unregister_pernet_subsys(&nf_log_syslog_net_ops); nf_log_unregister(&nf_ip_logger); nf_log_unregister(&nf_arp_logger); nf_log_unregister(&nf_ip6_logger); nf_log_unregister(&nf_netdev_logger); nf_log_unregister(&nf_bridge_logger); + unregister_pernet_subsys(&nf_log_syslog_net_ops); } module_init(nf_log_syslog_init); diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c index dbb226aa4c0ea..e576c5417433d 100644 --- a/net/netfilter/nfnetlink_log.c +++ b/net/netfilter/nfnetlink_log.c @@ -1179,8 +1179,8 @@ static void __exit nfnetlink_log_fini(void) { nfnetlink_subsys_unregister(&nfulnl_subsys); netlink_unregister_notifier(&nfulnl_rtnl_notifier); - unregister_pernet_subsys(&nfnl_log_net_ops); nf_log_unregister(&nfulnl_logger); + unregister_pernet_subsys(&nfnl_log_net_ops); } MODULE_DESCRIPTION("netfilter userspace logging"); -- 2.53.0