From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f53.google.com (mail-wm1-f53.google.com [209.85.128.53]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 616FB3FE640 for ; Wed, 29 Apr 2026 17:56:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.53 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777485379; cv=none; b=fOsOlsfhYGYvHnkbaUlIV8NSJT4nacybJt0sGkg4i8fRjXZJedlf9A2nEwGwGVryiC8sK7zoR2wFpTrC/EBtYhtv5Ema8ekOHJQV71nwGwI9yYyi6cNXJfWcCIMx2Lustt/5VGZC0MAYWquZehEmyYg6G6Xl+b4SNKKppz3I76Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777485379; c=relaxed/simple; bh=eDBirYq4pCbL+nEUiEp7cl5+N06I9yeNRMJUvi0dUZs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gE31Z0K3UsqPV/DKu+zeukwFoMnQkqvzoB5u5pnIPO5eEtSPQp0FP4VtWzmjQS1psLHitm784z2GXVXbnKVdfGWmBFEsG4N5JvtYcB/R1BnID29Uoa5XdqT2DThZRA+0LhE+KSI7E2sTdi0rOpaXYT0/ceCvWQIwMLj1yiNPW5E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=jYQAlbJM; arc=none smtp.client-ip=209.85.128.53 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="jYQAlbJM" Received: by mail-wm1-f53.google.com with SMTP id 5b1f17b1804b1-488a14c31eeso276715e9.0 for ; Wed, 29 Apr 2026 10:56:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1777485376; x=1778090176; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=ZAVLe7MO2A1MyrDF6a2t4MvPRiDZqS4DmH+U/JOcnYM=; b=jYQAlbJMAUmgBX14wyxFlZBhXAKj3S+TKPLSDiohw7yy20edVzYsqczSigBf0J6CcC ktDQiI+MWNeYMkIasiq6Qa6I8khKvtNF5t2q33GMs9LFFsuSvZuUIy88OuGlTYUP4IkD WPkh/d+tsh2lw6msVv4Q+TiPhfofGlpslXAeSx/2MpTgu6SLSRqstfmuT/4zkVjdmJOL FOo889lSGnqyx97fziO/SI+wjyWY2ZOWYsmPwZ9UTjf4w/BYKexvsrhONblzXMIHeHEd FmQL/73zTpBwt2H6vWHOIHk9wYs0vqoo7ffG7R2+fu40Cx1svYsuGwplU06b9E4pzZCy uO4g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1777485376; x=1778090176; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=ZAVLe7MO2A1MyrDF6a2t4MvPRiDZqS4DmH+U/JOcnYM=; b=YdPouiiXYiVeuq5+YQiCxZRTzaDufdptmOA18dGsTR5f1oy41iRmYRFR48G+FVRSHH Ymw4NqYeurXyoyQG6LAbeDevRGM6gW5Lrw73PLKvFiCHsl1YC7KnxsqLFypvgd+Dskoz GKjBWDZbVvMP4gpztMEi4Znuebs6dBmWqZSZPhF74gjJqqS67tzpAeBLfivl6LPOQimh v0VsoBAW3GI4jZmSX4QPmhaMbq9VO+5thYa6Pil4atQIwkFFsHrRTpf7PnzkDU5J4YFM DLVl2a/ZrF1nTV+HREP5wtzXxTZSalDWKArdEG/Tov3AuMHDfON4OuT+ykZXd0XS4LbZ TdRA== X-Forwarded-Encrypted: i=1; AFNElJ9PNLiLYFp8kCoD6RjXiHNyJEXzPK1nMcZdfFc8lxT0ltKrnJle+aqOwO4KoIergQlOAOqRwDg=@vger.kernel.org X-Gm-Message-State: AOJu0Yz00t7G/k6rCKgoDBGd7yZp8VwKAZ3lTKu48/+DxdBXETyxNZT1 mNOApMewrrjj+/QcldwrFbBc3TAzmeaKRdSiIi2NPvqBTzFM2P9RcKU= X-Gm-Gg: AeBDiesp2U3sSjTQQUnamd9AsbECudlsw0oUemAshO3Cp0JCflyqCwlzLor3JDkFCaI 4KAEgYVWgI26DzHQ2DRHSEwEsTgCPwJVluVhS4cvbA90f97mJUcTnh5sayPeLP1DldviWw0DLmv npFkG6WHHtIHOGOJKePJ1pD5KqzN8QZ4jaqKY9pu5/dkp5SzCN/SW1D2LaoLrfjwkziUhQO8iq4 EISk+Fwco/+knMWjOgklB8K+DMY1c6PHkz0sQyBHqIjXXYjQma0Tkbr19/oUewOt8E1lTBs9Lfw Fv6rFzIF0OMwsiLEeayP+eHsB9NDdoUgD5Tiv2QKYD5kwHkE8ddqNBu7Fu02EYZYtCA9DIi8AkB 1WZd2113MoLhjhR7O1n0wmKjVERH8DknWXdu8luYKT4FlAV5WuD+x5VcPY6TKvkbtsAEI2mnZHr KEI68= X-Received: by 2002:a05:600c:c048:b0:485:39b2:a47c with SMTP id 5b1f17b1804b1-48a77b22dedmr99590625e9.25.1777485375550; Wed, 29 Apr 2026 10:56:15 -0700 (PDT) Received: from debian.. ([2001:41d0:303:db6b::]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-447b3d48517sm6183750f8f.5.2026.04.29.10.56.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 29 Apr 2026 10:56:14 -0700 (PDT) From: Tristan Madani To: Pablo Neira Ayuso Cc: Florian Westphal , Phil Sutter , netfilter-devel@vger.kernel.org, netdev@vger.kernel.org, stable@vger.kernel.org, linux-kernel@vger.kernel.org, Tristan Madani Subject: [PATCH 1/2] netfilter: ip_tables: allocate hook ops before making table visible Date: Wed, 29 Apr 2026 17:56:11 +0000 Message-ID: <20260429175613.1459342-2-tristmd@gmail.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260429175613.1459342-1-tristmd@gmail.com> References: <20260429175613.1459342-1-tristmd@gmail.com> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Tristan Madani ipt_register_table() adds the table to the per-netns list via xt_register_table() before allocating the per-netns hook ops copy via kmemdup_array(). This leaves a window where the table is visible in the list with ops=NULL. If cleanup_net() runs during this window (e.g. due to concurrent netns teardown with failslab-induced allocation failures), the pre_exit callback finds the table via xt_find_table() and passes the NULL ops pointer to nf_unregister_net_hooks(), causing a NULL pointer dereference: general protection fault in nf_unregister_net_hooks+0xbc/0x150 RIP: nf_unregister_net_hooks (net/netfilter/core.c:613) Call Trace: ipt_unregister_table_pre_exit iptable_mangle_net_pre_exit ops_pre_exit_list cleanup_net Fix by moving the ops allocation before xt_register_table() so the table is never in the list without valid ops. Fixes: ae689334225f ("netfilter: ip_tables: pass table pointer via nf_hook_ops") Cc: stable@vger.kernel.org Signed-off-by: Tristan Madani --- net/ipv4/netfilter/ip_tables.c | 31 ++++++++++++++++--------------- 1 file changed, 16 insertions(+), 15 deletions(-) diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c index 23c8deff8095a..c47bc776eb4f2 100644 --- a/net/ipv4/netfilter/ip_tables.c +++ b/net/ipv4/netfilter/ip_tables.c @@ -1745,6 +1745,21 @@ int ipt_register_table(struct net *net, const struct xt_table *table, return ret; } + if (template_ops) { + num_ops = hweight32(table->valid_hooks); + if (num_ops == 0) { + xt_free_table_info(newinfo); + return -EINVAL; + } + + ops = kmemdup_array(template_ops, num_ops, sizeof(*ops), + GFP_KERNEL); + if (!ops) { + xt_free_table_info(newinfo); + return -ENOMEM; + } + } + new_table = xt_register_table(net, table, &bootstrap, newinfo); if (IS_ERR(new_table)) { struct ipt_entry *iter; @@ -1752,27 +1767,13 @@ int ipt_register_table(struct net *net, const struct xt_table *table, xt_entry_foreach(iter, loc_cpu_entry, newinfo->size) cleanup_entry(iter, net); xt_free_table_info(newinfo); + kfree(ops); return PTR_ERR(new_table); } - /* No template? No need to do anything. This is used by 'nat' table, it registers - * with the nat core instead of the netfilter core. - */ if (!template_ops) return 0; - num_ops = hweight32(table->valid_hooks); - if (num_ops == 0) { - ret = -EINVAL; - goto out_free; - } - - ops = kmemdup_array(template_ops, num_ops, sizeof(*ops), GFP_KERNEL); - if (!ops) { - ret = -ENOMEM; - goto out_free; - } - for (i = 0; i < num_ops; i++) ops[i].priv = new_table; -- 2.47.3