From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=217.70.190.124 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793782978; b=b4wrmoTqeYQbyGk8vN0rgotBXKgekSi4XYjo2IvwbSIbPZsuJL6VqvJ8Qht/azwRGXPJ mLvmYuvEZtPGwE+YlmB4884fuufdyXmIUM5qMyCfycQxMDQUqwddRu8X7mJTJXGNKywog LnDc5e7Tr5c5b5n/VuY6nIH5f50k6e7yGpYHtGRYp2Y19aeRn/hUGLlbQ1nMzhO7Y/8UU BRovlpdo7n0THU9mw7eB3ByBxG5tVy/cB9XDGu/YWNc1j1S9O7W6IKSppRzoAwT7B2S3O WLY5Wvkg1v/xP/j4hlkv5as2XsBKCbs3HlwztRQxG0z4ul0lQebn3WBvwM1uIrk6XaQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793782978; h=DMARC-Filter:DKIM-Signature:Received:From:To:Cc:Subject:Date: Message-ID:X-Mailer:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding:X-Spam-Status:X-Spam-Checker-Version; bh=bRwI7uwCHVVt6T7DMLyhA8VEKQ0FrttDo22yhPZt5LE=; b=YPxKW93Oi8rouehgnibxmml+UrutGF2HKpEIWbBIc6Ex2FKOqcGjMnDbMXRkjYcLY60E H0PZJZDp1Ju4lQs6WQDcpfT5rW5ZnCD/noQa5OFObgY+fI04W+Fj6xkbM4jb9psAGk5UB R8cpngA2FPwHn1N039G15GA7vN3UN/EJBmQG/nBK86ZQig63ZkLTaSsktSSp7XL2RR9mO DZxJylX3ZZB6eE6D6itGqTGY9lRjtLWKuKEbXgqWmt4qP41JrcgXloTC1y0s7qKzm4ZDa uc8IjJgShEhmC3AYSvA8JopLgxIbH6AOXSiEmeo1Ccw8rJOksBwqhkORxGbgJ1z8PaA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none header.from=netfilter.org; spf=pass smtp.mailfrom=netfilter.org; dkim=pass header.d=netfilter.org header.i=@netfilter.org header.a=rsa-sha256 header.s=2025 header.b=ERwVzww6; arc=none smtp.remote-ip=217.70.190.124 Received: from mail.netfilter.org (mail.netfilter.org [217.70.190.124]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4E4A6606D804; Wed, 4 Nov 2026 09:02:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 4E4A6606D804 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=netfilter.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=netfilter.org header.i=@netfilter.org header.a=rsa-sha256 header.s=2025 header.b=ERwVzww6 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=netfilter.org; s=2025; t=1793782963; bh=bRwI7uwCHVVt6T7DMLyhA8VEKQ0FrttDo22yhPZt5LE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ERwVzww6iR6P6s5bjkUKbLFdZTpr97P79pcliAuw899dDOSm8RH0pRnOCBsc4PjJs uBttg2EpXalahmZjxPgNRisAMKcdBGV5zq3ml58DCs5+PAeVdk1bN2TeDtWRXU/7dJ hkBjORxQq4XA6p1WFxttJvWCERyhFydwEh4+72SKRaSmJb8QOOsg7+vNUqtcqQBqRD sycrCg9Dom6mru5gLVg2WPR2Urai/jF5DcUfn6iDy4QW74PWnSSYVRdzDZh3DZ3PnJ lwzMfhfBKY8Ekxlx7paHWH+S7+e5AbveVGlQC6A4cA5mNAayV1mYltJ7MO0ubvb/zF ALpZ5/pMsa0LQ== Received: from localhost.localdomain (mail-agni [217.70.190.124]) by mail.netfilter.org (Postfix) with ESMTPSA id 39C066007D; Wed, 4 Nov 2026 10:02:43 +0100 (CET) From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Cc: davem@davemloft.net, netdev@vger.kernel.org, kuba@kernel.org, pabeni@redhat.com, edumazet@kernel.org, horms@kernel.org, fw@strlen.de, ja@ssi.bg Subject: [PATCH net 08/13] netfilter: bridge: use DEBUG_NET_WARN_ON_ONCE in nf_ct_bridge_refrag() Date: Wed, 4 Nov 2026 10:02:19 +0100 Message-ID: <20261104090224.750548-9-pablo@netfilter.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20261104090224.750548-1-pablo@netfilter.org> References: <20261104090224.750548-1-pablo@netfilter.org> X-Mailing-List: netdev@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Laveesh Bansal nf_ct_bridge_refrag() warns when skb->protocol is neither IPv4 nor IPv6. A vlan filtering bridge can get there with a vlan ethertype: if the protocol of the tag of a frame differs from the vlan_protocol of the bridge, br_allowed_ingress() moves the tag back into the packet after NF_BR_PRE_ROUTING, where bridge conntrack has already defragmented it. Anyone who can send fragments into a port of such a bridge can trigger the warning, which takes the machine down with panic_on_warn. The packet is dropped either way, so only warn on kernels built with CONFIG_DEBUG_NET. This only avoids the warning. Such fragmented packets are still dropped. syzbot reported the warning. It keeps triggering on CONFIG_DEBUG_NET kernels until the vlan tag is handled, which is left for a follow-up: https://syzkaller.appspot.com/bug?extid=a8ba738fe2db6b4bb27f Fixes: 3c171f496ef5 ("netfilter: bridge: add connection tracking system") Assisted-by: LLM Signed-off-by: Laveesh Bansal Signed-off-by: Pablo Neira Ayuso --- net/bridge/netfilter/nf_conntrack_bridge.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/bridge/netfilter/nf_conntrack_bridge.c b/net/bridge/netfilter/nf_conntrack_bridge.c index b5444335b86f..8c83dc05114b 100644 --- a/net/bridge/netfilter/nf_conntrack_bridge.c +++ b/net/bridge/netfilter/nf_conntrack_bridge.c @@ -358,7 +358,7 @@ nf_ct_bridge_refrag(struct sk_buff *skb, const struct nf_hook_state *state, nf_br_ip6_fragment(state->net, state->sk, skb, &data, output); break; default: - WARN_ON_ONCE(1); + DEBUG_NET_WARN_ON_ONCE(1); return NF_DROP; } -- 2.47.3