{"id":2231564,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2231564/?format=json","web_url":"http://patchwork.ozlabs.org/project/netfilter-devel/patch/20260430202547.274256-1-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":"<20260430202547.274256-1-pablo@netfilter.org>","date":"2026-04-30T20:25:44","name":"[nf,v6,1/4] 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/20260430202547.274256-1-pablo@netfilter.org/mbox/","series":[{"id":502378,"url":"http://patchwork.ozlabs.org/api/1.1/series/502378/?format=json","web_url":"http://patchwork.ozlabs.org/project/netfilter-devel/list/?series=502378","date":"2026-04-30T20:25:46","name":"[nf,v6,1/4] netfilter: flowtable: ensure sufficient headroom in xmit path","version":6,"mbox":"http://patchwork.ozlabs.org/series/502378/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2231564/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2231564/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=FR0nSf4K;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c0a:e001:db::12fc:5321; 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t=1777580755; c=relaxed/simple;\n\tbh=XiaLhc82AWSwA/xbvDKYzddYX2MAEQ5dMhRdEWNzMYE=;\n\th=From:To:Subject:Date:Message-ID:MIME-Version;\n b=pKj5Mc1DVCWkXrarvF3wx6YFMcrswYKPWjnbZDfFJcgoD8yd0yQW2mzQ5o4S1K9a8e6r4f7tUogPHuzaok9tODmDdaNVltfKZ6AQRxEUX6AQOObvs/aePaMpcQcfX37kjzb+58DIZsCbjPk7J/Ytlh4QDhBB8IElpvT3rfv/uqM=","ARC-Authentication-Results":"i=1; smtp.subspace.kernel.org;\n dmarc=none (p=none dis=none) header.from=netfilter.org;\n spf=pass smtp.mailfrom=netfilter.org;\n dkim=pass (2048-bit key) header.d=netfilter.org header.i=@netfilter.org\n header.b=FR0nSf4K; arc=none smtp.client-ip=217.70.190.124","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed; d=netfilter.org;\n\ts=2025; t=1777580750;\n\tbh=R5eYrL/OJys5c/cCDLts4eZUN1k2IbSq4iDqkDEFXac=;\n\th=From:To:Subject:Date:From;\n\tb=FR0nSf4KWBOF6XbWyedke6OlNPhomS6mlNWHGNcfjN6mEPW/AbSKI2P9t6z6Weauk\n\t IEGkthM/mTpX2e8/M1q/HG1iiFkgk5U55Bq2ACJjdQUorXZGWNFCbzWYYVEDXEr7hb\n\t Nd29dDHKgnBmL7ST9rvXqk4V/FJdS7DOdwm2ieYLDH9j02NUkn1UIYsVh8oWQRd6Bt\n\t B9kDaga7nRfg0dFgn1tt6uQ7bwikTP7k5Xu0tny2uBb3peo7Nj9f/QdGBJAV1T1SHZ\n\t gMbWyCAAdGbqj7hWQDkwyT1D+I9BBvzqKdiWZAnprgioIeDy1o+ANAvpUSSrhURY3f\n\t kHG9/CamVtTmA==","From":"Pablo Neira Ayuso ","To":"netfilter-devel@vger.kernel.org","Subject":"[PATCH nf,v6 1/4] netfilter: flowtable: ensure sufficient headroom in\n xmit path","Date":"Thu, 30 Apr 2026 22:25:44 +0200","Message-ID":"<20260430202547.274256-1-pablo@netfilter.org>","X-Mailer":"git-send-email 2.47.3","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---\nv6: no changes\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":["nf","v6","1/4"]}