From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.netfilter.org (mail.netfilter.org [217.70.190.124]) (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 5DB1D39E19A; Fri, 1 May 2026 12:22:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.190.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777638179; cv=none; b=CfuiRbGKtUT+aoYqa4TonwD9qmFwvDWSDSbpuDuO23Aa2nNuEKdIuRGZs9+WkiNSOBGUhf2IIRZ87uBkCDEPXki4hf65BlA2EYzWyvc5rWlrjPPBc/3y28yPSTRYwZwZ8f8eYaWieyCv3jN3Kx7WmYnzg/NEap3PGiYy/J01iAI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777638179; c=relaxed/simple; bh=vw8V2bgEokAN79/9zttZ98KDTtS44QsRqi7No3AoXFs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ewxYdgi1Or0w0nRoosL0Hz8YyuIVSp4SByirUKOC42X+uUEFGGNEBE99qHXBt8htcnmXT+3XsyaohVUuxNMxYhlBxMz+fqtZ/L1tpMz6MsedBPdy3juVs5AwSRbnJAGOZgVerUGLB7hE9Yg7NqEnBj2Fe+zwVBH+LQcX8dhlAUk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org; spf=pass smtp.mailfrom=netfilter.org; dkim=pass (2048-bit key) header.d=netfilter.org header.i=@netfilter.org header.b=FJ7wJpX2; arc=none smtp.client-ip=217.70.190.124 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) header.d=netfilter.org header.i=@netfilter.org header.b="FJ7wJpX2" Received: from localhost.localdomain (mail-agni [217.70.190.124]) by mail.netfilter.org (Postfix) with ESMTPSA id 77E9960253; Fri, 1 May 2026 14:22:56 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=netfilter.org; s=2025; t=1777638176; bh=mcnUQt9LLvOexCF57nZXeIuY1C0t9ce1MbG6y5d+u/4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FJ7wJpX2QNoUO2H82eEvYS9QGvwWID2BjUBqInVWp5Q/y0bTQePG7v2iAIhDlkCfg j68Z3SV2XzYCkBvANwyE7MBJhaHLuEjHxW/uCCS2+hdXRskN5UdNzLInMUaEbMD7/X QjedjHwN+g1KIj1LSwczcfWb2qN/bxlM7XDKSBOq4Wk9n2WpQW9XdOxZnyJQKCgXuh Zr3VIqL2VPDmcVYtTb8lu+KpGnG6O49UUZX+BsaMFuZKtcsuaWw896Zdrj9SPaq/Q/ Th2NjgmKsfrUDQVnWzzTn2eK1q5VJeH0bl1X5X5uD2zV8RT715hjqgo39NQ2s8Q7aT MAswOYXU/l2tQ== 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@google.com, fw@strlen.de, horms@kernel.org Subject: [PATCH net 11/14] netfilter: flowtable: ensure sufficient headroom in xmit path Date: Fri, 1 May 2026 14:22:34 +0200 Message-ID: <20260501122237.296262-12-pablo@netfilter.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260501122237.296262-1-pablo@netfilter.org> References: <20260501122237.296262-1-pablo@netfilter.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Check for headroom and call skb_expand_head() like in the IP output path to ensure there is sufficient headroom for the mac header when forwarding this packet as suggested by sashiko. Fixes: b5964aac51e0 ("netfilter: flowtable: consolidate xmit path") Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nf_flow_table_ip.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c index dbd7644fdbeb..8d5fb7e940a1 100644 --- a/net/netfilter/nf_flow_table_ip.c +++ b/net/netfilter/nf_flow_table_ip.c @@ -471,8 +471,17 @@ struct nf_flow_xmit { static unsigned int nf_flow_queue_xmit(struct net *net, struct sk_buff *skb, struct nf_flow_xmit *xmit) { - skb->dev = xmit->outdev; - dev_hard_header(skb, skb->dev, ntohs(skb->protocol), + struct net_device *dev = xmit->outdev; + unsigned int hh_len = LL_RESERVED_SPACE(dev); + + if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) { + skb = skb_expand_head(skb, hh_len); + if (!skb) + return NF_STOLEN; + } + + skb->dev = dev; + dev_hard_header(skb, dev, ntohs(skb->protocol), xmit->dest, xmit->source, skb->len); dev_queue_xmit(skb); -- 2.47.3