{"id":2227074,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2227074/?format=json","web_url":"http://patchwork.ozlabs.org/project/netfilter-devel/patch/20260423072155.352333-1-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":"<20260423072155.352333-1-pablo@netfilter.org>","date":"2026-04-23T07:21:53","name":"[nf,v4,1/3] netfilter: replace skb_try_make_writable() by skb_ensure_writable()","commit_ref":null,"pull_url":null,"state":"changes-requested","archived":false,"hash":"c3281a270636241f67c06af26678734bf7e0171c","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/20260423072155.352333-1-pablo@netfilter.org/mbox/","series":[{"id":501153,"url":"http://patchwork.ozlabs.org/api/1.1/series/501153/?format=json","web_url":"http://patchwork.ozlabs.org/project/netfilter-devel/list/?series=501153","date":"2026-04-23T07:21:54","name":"[nf,v4,1/3] netfilter: replace skb_try_make_writable() by skb_ensure_writable()","version":4,"mbox":"http://patchwork.ozlabs.org/series/501153/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2227074/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2227074/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=uRByGwLi;\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; helo=sea.lore.kernel.org;\n envelope-from=netfilter-devel+bounces-12147-incoming=patchwork.ozlabs.org@vger.kernel.org;\n receiver=patchwork.ozlabs.org)","smtp.subspace.kernel.org;\n\tdkim=pass (2048-bit key) header.d=netfilter.org header.i=@netfilter.org\n header.b=\"uRByGwLi\"","smtp.subspace.kernel.org;\n arc=none smtp.client-ip=217.70.190.124","smtp.subspace.kernel.org;\n dmarc=none (p=none dis=none) header.from=netfilter.org","smtp.subspace.kernel.org;\n spf=pass smtp.mailfrom=netfilter.org"],"Received":["from sea.lore.kernel.org (sea.lore.kernel.org [172.234.253.10])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519 server-signature ECDSA (secp384r1) server-digest SHA384)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4g1SLr4F5Dz1yCv\n\tfor ; Thu, 23 Apr 2026 17:26:12 +1000 (AEST)","from smtp.subspace.kernel.org (conduit.subspace.kernel.org\n [100.90.174.1])\n\tby sea.lore.kernel.org (Postfix) with ESMTP id DE95630158A2\n\tfor ; Thu, 23 Apr 2026 07:22:05 +0000 (UTC)","from localhost.localdomain (localhost.localdomain [127.0.0.1])\n\tby smtp.subspace.kernel.org (Postfix) with ESMTP id 44AB12D73B8;\n\tThu, 23 Apr 2026 07:22:05 +0000 (UTC)","from mail.netfilter.org (mail.netfilter.org [217.70.190.124])\n\t(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby smtp.subspace.kernel.org (Postfix) with ESMTPS id 332EE282F36\n\tfor ; Thu, 23 Apr 2026 07:22:01 +0000 (UTC)","from localhost.localdomain (mail-agni [217.70.190.124])\n\tby mail.netfilter.org (Postfix) with ESMTPSA id 454DE602C1\n\tfor ; Thu, 23 Apr 2026 09:21:59 +0200 (CEST)"],"ARC-Seal":"i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116;\n\tt=1776928924; cv=none;\n b=mRn0NP4HcAfldX5GspWYsjFc5GFt62KpIYFWbGP7nPmj5KIPM0qZGFgFKd6tQ+lkf768VsnM7f9s3MwVCRJpI/9RMlgZQLKWJ8XRokW+uPy8t6iYXt5v5hZ2zrZhyStUBEDbVZ/DsRsyY53a7k/yqey9rtbIS3YTOHHfz6JKL0w=","ARC-Message-Signature":"i=1; a=rsa-sha256; d=subspace.kernel.org;\n\ts=arc-20240116; t=1776928924; c=relaxed/simple;\n\tbh=Te3jANmpVz14O2tVMH6PtSvH4FX0C/uEhZ6nQ0zep/Q=;\n\th=From:To:Subject:Date:Message-ID:MIME-Version;\n b=KVvCZLurYg8vLlwatbHzZ2xRPJoCBhEetypdjDadyVTWYP5a55W/vP3TATTIwbuyBI2bVCxxsHeOGeiBirR6ajZ/jJLJFOk0OjqUSK7i4XV92fv9FUkjoePMtRmb1Z8KHmFTBrnrn1cpAW0Ac/ceunKQXDIDixPLUFe3BAxVJbs=","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=uRByGwLi; 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=1776928919;\n\tbh=DtpZ4Lk1uPMnmsW+kOGn+BFCEyG0rIb9b6XR0vUIqHo=;\n\th=From:To:Subject:Date:From;\n\tb=uRByGwLi4xYrIVzVRqrV2JCGwvWUbt4T0+RqDpMyNaSsNnmUblPdPWO2Kj4EMUuyY\n\t Rz82QLnJiinLolwSUd0AeyXDoX372fQeyAPpDwngsVcK93HVgHeXByoX52T8ne0JfZ\n\t YlWyeaQnpPY7jYCuT58Fc2i9np6NG8bxuIfbnxm/S9J50+JtKqR2wvaXbiYdrExIOd\n\t cq3u3Ugw6WwHb4rjNmc0uTUFREzuK+3TMNa7w9K3b+L1Z/FQHzVErZdWC7dJleXjDV\n\t orFV8GYJsK4xO+rD4j9SkmvhCR5X5hJvqiJauFxu0UPTiq8AOSay+xlf7s1pVB6+I/\n\t jfRbetT7o4ZFg==","From":"Pablo Neira Ayuso ","To":"netfilter-devel@vger.kernel.org","Subject":"[PATCH nf,v4 1/3] netfilter: replace skb_try_make_writable() by\n skb_ensure_writable()","Date":"Thu, 23 Apr 2026 09:21:53 +0200","Message-ID":"<20260423072155.352333-1-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":"skb_try_make_writable() only works on clones and uncloned packets might\nhave their network header in paged fragments.\n\nnft_fwd needs to work for the ingress and egress hooks, but the egress\nhook where skb->data points to the mac header, use skb_network_offset()\nto include the mac header. The flowtable is fine since it already uses\nthe transport offset.\n\nFixes: d32de98ea70f (\"netfilter: nft_fwd_netdev: allow to forward packets via neighbour layer\")\nFixes: 7d2086871762 (\"netfilter: nf_flow_table: move ipv4 offload hook code to nf_flow_table\")\nSigned-off-by: Pablo Neira Ayuso \n---\nv4: no changes.\n\n net/netfilter/nf_flow_table_ip.c | 4 ++--\n net/netfilter/nft_fwd_netdev.c | 5 +++--\n 2 files changed, 5 insertions(+), 4 deletions(-)","diff":"diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c\nindex fd56d663cb5b..dbd7644fdbeb 100644\n--- a/net/netfilter/nf_flow_table_ip.c\n+++ b/net/netfilter/nf_flow_table_ip.c\n@@ -524,7 +524,7 @@ static int nf_flow_offload_forward(struct nf_flowtable_ctx *ctx,\n \t\treturn 0;\n \t}\n \n-\tif (skb_try_make_writable(skb, thoff + ctx->hdrsize))\n+\tif (skb_ensure_writable(skb, thoff + ctx->hdrsize))\n \t\treturn -1;\n \n \tflow_offload_refresh(flow_table, flow, false);\n@@ -1037,7 +1037,7 @@ static int nf_flow_offload_ipv6_forward(struct nf_flowtable_ctx *ctx,\n \t\treturn 0;\n \t}\n \n-\tif (skb_try_make_writable(skb, thoff + ctx->hdrsize))\n+\tif (skb_ensure_writable(skb, thoff + ctx->hdrsize))\n \t\treturn -1;\n \n \tflow_offload_refresh(flow_table, flow, false);\ndiff --git a/net/netfilter/nft_fwd_netdev.c b/net/netfilter/nft_fwd_netdev.c\nindex 4bce36c3a6a0..2cc809303ce8 100644\n--- a/net/netfilter/nft_fwd_netdev.c\n+++ b/net/netfilter/nft_fwd_netdev.c\n@@ -100,6 +100,7 @@ static void nft_fwd_neigh_eval(const struct nft_expr *expr,\n \tint oif = regs->data[priv->sreg_dev];\n \tunsigned int verdict = NF_STOLEN;\n \tstruct sk_buff *skb = pkt->skb;\n+\tint nhoff = skb_network_offset(skb);\n \tstruct net_device *dev;\n \tint neigh_table;\n \n@@ -111,7 +112,7 @@ static void nft_fwd_neigh_eval(const struct nft_expr *expr,\n \t\t\tverdict = NFT_BREAK;\n \t\t\tgoto out;\n \t\t}\n-\t\tif (skb_try_make_writable(skb, sizeof(*iph))) {\n+\t\tif (skb_ensure_writable(skb, nhoff + sizeof(*iph))) {\n \t\t\tverdict = NF_DROP;\n \t\t\tgoto out;\n \t\t}\n@@ -132,7 +133,7 @@ static void nft_fwd_neigh_eval(const struct nft_expr *expr,\n \t\t\tverdict = NFT_BREAK;\n \t\t\tgoto out;\n \t\t}\n-\t\tif (skb_try_make_writable(skb, sizeof(*ip6h))) {\n+\t\tif (skb_ensure_writable(skb, nhoff + sizeof(*ip6h))) {\n \t\t\tverdict = NF_DROP;\n \t\t\tgoto out;\n \t\t}\n","prefixes":["nf","v4","1/3"]}