{"id":2231778,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2231778/?format=json","web_url":"http://patchwork.ozlabs.org/project/netfilter-devel/patch/20260501122237.296262-12-pablo@netfilter.org/","project":{"id":26,"url":"http://patchwork.ozlabs.org/api/1.1/projects/26/?format=json","name":"Netfilter Development","link_name":"netfilter-devel","list_id":"netfilter-devel.vger.kernel.org","list_email":"netfilter-devel@vger.kernel.org","web_url":null,"scm_url":null,"webscm_url":null},"msgid":"<20260501122237.296262-12-pablo@netfilter.org>","date":"2026-05-01T12:22:34","name":"[net,11/14] netfilter: flowtable: ensure sufficient headroom in xmit path","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"5f3c343909659312cc5092379b127dacb59c1a84","submitter":{"id":1315,"url":"http://patchwork.ozlabs.org/api/1.1/people/1315/?format=json","name":"Pablo Neira Ayuso","email":"pablo@netfilter.org"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/netfilter-devel/patch/20260501122237.296262-12-pablo@netfilter.org/mbox/","series":[{"id":502449,"url":"http://patchwork.ozlabs.org/api/1.1/series/502449/?format=json","web_url":"http://patchwork.ozlabs.org/project/netfilter-devel/list/?series=502449","date":"2026-05-01T12:22:23","name":"[net,01/14] netfilter: replace skb_try_make_writable() by skb_ensure_writable()","version":1,"mbox":"http://patchwork.ozlabs.org/series/502449/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2231778/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2231778/checks/","tags":{},"headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","netfilter-devel@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=netfilter.org header.i=@netfilter.org\n header.a=rsa-sha256 header.s=2025 header.b=FJ7wJpX2;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=172.234.253.10; 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a=rsa-sha256; c=relaxed/relaxed; d=netfilter.org;\n\ts=2025; t=1777638176;\n\tbh=mcnUQt9LLvOexCF57nZXeIuY1C0t9ce1MbG6y5d+u/4=;\n\th=From:To:Cc:Subject:Date:In-Reply-To:References:From;\n\tb=FJ7wJpX2QNoUO2H82eEvYS9QGvwWID2BjUBqInVWp5Q/y0bTQePG7v2iAIhDlkCfg\n\t j68Z3SV2XzYCkBvANwyE7MBJhaHLuEjHxW/uCCS2+hdXRskN5UdNzLInMUaEbMD7/X\n\t QjedjHwN+g1KIj1LSwczcfWb2qN/bxlM7XDKSBOq4Wk9n2WpQW9XdOxZnyJQKCgXuh\n\t Zr3VIqL2VPDmcVYtTb8lu+KpGnG6O49UUZX+BsaMFuZKtcsuaWw896Zdrj9SPaq/Q/\n\t Th2NjgmKsfrUDQVnWzzTn2eK1q5VJeH0bl1X5X5uD2zV8RT715hjqgo39NQ2s8Q7aT\n\t MAswOYXU/l2tQ==","From":"Pablo Neira Ayuso ","To":"netfilter-devel@vger.kernel.org","Cc":"davem@davemloft.net,\n\tnetdev@vger.kernel.org,\n\tkuba@kernel.org,\n\tpabeni@redhat.com,\n\tedumazet@google.com,\n\tfw@strlen.de,\n\thorms@kernel.org","Subject":"[PATCH net 11/14] netfilter: flowtable: ensure sufficient headroom in\n 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":"netfilter-devel@vger.kernel.org","List-Id":"","List-Subscribe":"","List-Unsubscribe":"","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit"},"content":"Check for headroom and call skb_expand_head() like in the IP output\npath to ensure there is sufficient headroom for the mac header when\nforwarding this packet as suggested by sashiko.\n\nFixes: b5964aac51e0 (\"netfilter: flowtable: consolidate xmit path\")\nSigned-off-by: Pablo Neira Ayuso \n---\n net/netfilter/nf_flow_table_ip.c | 13 +++++++++++--\n 1 file changed, 11 insertions(+), 2 deletions(-)","diff":"diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c\nindex dbd7644fdbeb..8d5fb7e940a1 100644\n--- a/net/netfilter/nf_flow_table_ip.c\n+++ b/net/netfilter/nf_flow_table_ip.c\n@@ -471,8 +471,17 @@ struct nf_flow_xmit {\n static unsigned int nf_flow_queue_xmit(struct net *net, struct sk_buff *skb,\n \t\t\t\t struct nf_flow_xmit *xmit)\n {\n-\tskb->dev = xmit->outdev;\n-\tdev_hard_header(skb, skb->dev, ntohs(skb->protocol),\n+\tstruct net_device *dev = xmit->outdev;\n+\tunsigned int hh_len = LL_RESERVED_SPACE(dev);\n+\n+\tif (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) {\n+\t\tskb = skb_expand_head(skb, hh_len);\n+\t\tif (!skb)\n+\t\t\treturn NF_STOLEN;\n+\t}\n+\n+\tskb->dev = dev;\n+\tdev_hard_header(skb, dev, ntohs(skb->protocol),\n \t\t\txmit->dest, xmit->source, skb->len);\n \tdev_queue_xmit(skb);\n \n","prefixes":["net","11/14"]}