{"id":2221384,"url":"http://patchwork.ozlabs.org/api/1.2/patches/2221384/?format=json","web_url":"http://patchwork.ozlabs.org/project/netfilter-devel/patch/20260409104911.722698-2-bestswngs@gmail.com/","project":{"id":26,"url":"http://patchwork.ozlabs.org/api/1.2/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,"list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<20260409104911.722698-2-bestswngs@gmail.com>","list_archive_url":null,"date":"2026-04-09T10:49:12","name":"[v2] netfilter: nft_fwd_netdev: use recursion counter in neigh egress path","commit_ref":null,"pull_url":null,"state":"under-review","archived":false,"hash":"00d4880e156e684e260291c466dde58df87616ff","submitter":{"id":92941,"url":"http://patchwork.ozlabs.org/api/1.2/people/92941/?format=json","name":"Weiming Shi","email":"bestswngs@gmail.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/netfilter-devel/patch/20260409104911.722698-2-bestswngs@gmail.com/mbox/","series":[{"id":499274,"url":"http://patchwork.ozlabs.org/api/1.2/series/499274/?format=json","web_url":"http://patchwork.ozlabs.org/project/netfilter-devel/list/?series=499274","date":"2026-04-09T10:49:12","name":"[v2] netfilter: nft_fwd_netdev: use recursion counter in neigh egress path","version":2,"mbox":"http://patchwork.ozlabs.org/series/499274/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2221384/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2221384/checks/","tags":{},"related":[],"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=gmail.com header.i=@gmail.com header.a=rsa-sha256\n header.s=20251104 header.b=WwfcPWkk;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c15:e001:75::12fc:5321; helo=sin.lore.kernel.org;\n envelope-from=netfilter-devel+bounces-11758-incoming=patchwork.ozlabs.org@vger.kernel.org;\n receiver=patchwork.ozlabs.org)","smtp.subspace.kernel.org;\n\tdkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com\n header.b=\"WwfcPWkk\"","smtp.subspace.kernel.org;\n arc=none smtp.client-ip=209.85.216.46","smtp.subspace.kernel.org;\n dmarc=pass (p=none dis=none) header.from=gmail.com","smtp.subspace.kernel.org;\n spf=pass smtp.mailfrom=gmail.com"],"Received":["from sin.lore.kernel.org (sin.lore.kernel.org\n [IPv6:2600:3c15:e001:75::12fc:5321])\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 4frxXT1tyfz1xy1\n\tfor ; Thu, 09 Apr 2026 20:50:01 +1000 (AEST)","from smtp.subspace.kernel.org (conduit.subspace.kernel.org\n [100.90.174.1])\n\tby sin.lore.kernel.org (Postfix) with ESMTP id C5639300A25F\n\tfor ; Thu, 9 Apr 2026 10:49:56 +0000 (UTC)","from localhost.localdomain (localhost.localdomain [127.0.0.1])\n\tby smtp.subspace.kernel.org (Postfix) with ESMTP id 609323BED30;\n\tThu, 9 Apr 2026 10:49:55 +0000 (UTC)","from mail-pj1-f46.google.com (mail-pj1-f46.google.com\n [209.85.216.46])\n\t(using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits))\n\t(No client certificate requested)\n\tby smtp.subspace.kernel.org (Postfix) with ESMTPS id A6BE437B402\n\tfor ; Thu, 9 Apr 2026 10:49:51 +0000 (UTC)","by mail-pj1-f46.google.com with SMTP id\n 98e67ed59e1d1-358e3cc5e7eso470029a91.0\n for ;\n Thu, 09 Apr 2026 03:49:51 -0700 (PDT)","from SLSGDTSWING002.tail0ac356.ts.net ([129.126.109.177])\n by smtp.gmail.com with ESMTPSA id\n 98e67ed59e1d1-35e3503b278sm3724426a91.16.2026.04.09.03.49.47\n (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256);\n Thu, 09 Apr 2026 03:49:50 -0700 (PDT)"],"ARC-Seal":"i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116;\n\tt=1775731794; cv=none;\n b=QAWP9JTkiYkvO7bQt0cw+fGCFI8jTf5Fag1ag4Y6FGLAxAWIOArUl+doANa8KY/5mKViAfiMYXWUixC0qYsJzKD+f9rRY8oCpt6AG5M+oREJYKUdJrZVg1+uleUhJvZ3lk84ZuYqjVXQXiKaQ6XaU3rX7WQ5I3XpuxGA+zTtqrA=","ARC-Message-Signature":"i=1; a=rsa-sha256; d=subspace.kernel.org;\n\ts=arc-20240116; t=1775731794; c=relaxed/simple;\n\tbh=JNT33Wmq43E/C5jtUNTbbsnfLcnJM8zf0ttEv/gKCIs=;\n\th=From:To:Cc:Subject:Date:Message-ID:MIME-Version;\n b=cm+Sif9YNwJJWR8ODMZwUSu1Bxl37H023vwXvFmu57gYXknjUQzJXfFcbk9iXMdlj9+8vevYlfOxn+UjxdE67WMSCsQMGkO1toEX7O5gzELR/ptwsxFppq0EuZCmXnlRZ/sNtNo4P+1OLDNK1tK4elL9wZLjfYwN8XZW3wJ+n4Q=","ARC-Authentication-Results":"i=1; smtp.subspace.kernel.org;\n dmarc=pass (p=none dis=none) header.from=gmail.com;\n spf=pass smtp.mailfrom=gmail.com;\n dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com\n header.b=WwfcPWkk; arc=none smtp.client-ip=209.85.216.46","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n d=gmail.com; s=20251104; t=1775731791; x=1776336591;\n darn=vger.kernel.org;\n h=content-transfer-encoding:mime-version:message-id:date:subject:cc\n :to:from:from:to:cc:subject:date:message-id:reply-to;\n bh=Ukbyd6N1MhmvxaPd3moBUEUJpBd5mNCDxCGpsq2J5LA=;\n b=WwfcPWkkwJgxDug0ekTYyXrV/xouXrB9HBUMAfrkdkjELiDzkLUX2IODG1upfUYKYS\n jQg2msyCQT2bCu989fFE1Fo3LBhWrj24SXXnKNVBEmtaYBzici0xmgW4x7yUQCsmr4Ng\n dUmgiCYZ1N0VcOTT3NuU09Ox/EjbbNq2zYCgLagY68DHcXt8h5101pDtWyWLJ2Y2eZTH\n ocM91IvDxQV1T59o+yWxCbdcPLiSTgLfGp7zmk9TMjf8XsNpBs9AHYYkgyCui7svfK+N\n ZGGrjjL8LlptLrTzzzI2MmViOu5jDKgOZ1Jn38iEOLJY6o8poGqBvKW+pdqV+EAlDsw6\n 1K5w==","X-Google-DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n d=1e100.net; s=20251104; t=1775731791; x=1776336591;\n h=content-transfer-encoding:mime-version:message-id:date:subject:cc\n :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date\n :message-id:reply-to;\n bh=Ukbyd6N1MhmvxaPd3moBUEUJpBd5mNCDxCGpsq2J5LA=;\n b=j2pALB+NEAG6GueCq9vRrH1WpwX6T1xv49l3BoxNtuyokYeffoQzOm3+T22Z/e4wcR\n Z9Pvv+BJj9IAsCpUcJDqDLoEHYjOF6R9WHAb6jlwI9nCEBPYJMvykokC9890ePMRpJih\n YKmZ6pGFOxtX+6A+K86ZMySsojijGaGNq6rvfHZ5VInEXWRd8VT4Qd02uIEfokn++NsQ\n gzAhqtIUGYrj71lfR+9ymlZRoQM7SLtBFMDIzDiwQN5v9+Txn4o8YvdvUBcg3vNsDdXB\n sn0VRxmt8pFZ7yX8jdJlSU+xXkz320MQ0mb3c/VcCcCW91B7asdH5Aj6EMlbC0WtEdsg\n c3zA==","X-Forwarded-Encrypted":"i=1;\n AJvYcCXQ1Y5x3WTvtg84jhA60YsqycbYlUbstssvHCcS3E3uJ95Xs0UrnfPAQMoyIMrlucoqxMg23Ahz/AdbEOj9rdM=@vger.kernel.org","X-Gm-Message-State":"AOJu0YwxkDYBVCE3meIqXDC1kaLyRrAn5/RaqHV1tIVRTb6/+zzOdkpt\n\tkc7xnY/QyaSsRjalfVX7FEpDfwvUQoYU4ydwIspUd0WhdFnmpn+Mo1gj","X-Gm-Gg":"AeBDievlXFlPaSs5qMmSPR2ijat+7d0VOH5Ibu21AAhccXqadSHEWoYtqCFrU3dXF74\n\tobWir18pso2Y5+CsZuy2+Zh026PaNZoeR4dobE7QqdpHB3Bn+NfPjnlpdhXOc8TFWzdYyZg40l0\n\tEnT69HH707HSOGhnLDpZTB+n5UJkuMEivtoiBfN4SFwlSy/TmfHwLYTfqFfuEXwYxAS0d66najA\n\tOtQh7c6tPtRl9veionwJqS+/FWZihC4Avn/v5R7BWj31pfouFo5rLYwKKyIHf7muy3CnQ66aU9I\n\tMXA1cWsXUoAXog7jsJQZlJlFtVCxuWwYa9wQTdh/13jNEwA5Xg7LBHpfaI1vcmnj1n2qadwIDdH\n\tIPP+Gx0IBg8KhhBkX2W8wOCeuuEDx5VV7loB1N9Ovjlbb8BwdVAHy9QjfF3nEj7CRoSjhzE3m7w\n\t3WnQ5LyZhEudkLYbARyKeE3OHSsDgIQvnsf24l4j5uhJ9rPNTElIjf17jMLFulYYtg+kNv7/DvH\n\tXunqebMEwLc","X-Received":"by 2002:a17:90b:5585:b0:355:35b0:8b78 with SMTP id\n 98e67ed59e1d1-35de69a6545mr23786223a91.27.1775731790627;\n Thu, 09 Apr 2026 03:49:50 -0700 (PDT)","From":"Weiming Shi ","To":"Pablo Neira Ayuso ,\n\tFlorian Westphal ,\n\t\"David S . Miller\" ,\n\tEric Dumazet ,\n\tJakub Kicinski ,\n\tPaolo Abeni ","Cc":"Phil Sutter ,\n\tSimon Horman ,\n\tnetfilter-devel@vger.kernel.org,\n\tcoreteam@netfilter.org,\n\tnetdev@vger.kernel.org,\n\tXiang Mei ,\n\tWeiming Shi ","Subject":"[PATCH v2] netfilter: nft_fwd_netdev: use recursion counter in neigh\n egress path","Date":"Thu, 9 Apr 2026 18:49:12 +0800","Message-ID":"<20260409104911.722698-2-bestswngs@gmail.com>","X-Mailer":"git-send-email 2.43.0","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":"nft_fwd_neigh can be used in egress chains (NF_NETDEV_EGRESS). When the\nforwarding rule targets the same device or two devices forward to each\nother, neigh_xmit() triggers dev_queue_xmit() which re-enters\nnf_hook_egress(), causing infinite recursion and stack overflow.\n\nMove the nf_get_nf_dup_skb_recursion() accessor and NF_RECURSION_LIMIT\nto the shared header nf_dup_netdev.h as a static inline, so that\nnft_fwd_netdev can use the recursion counter directly without exported\nfunction call overhead. Guard neigh_xmit() with the same recursion\nlimit already used in nf_do_netdev_egress().\n\nFixes: f87b9464d152 (\"netfilter: nft_fwd_netdev: Support egress hook\")\nReported-by: Xiang Mei \nSigned-off-by: Weiming Shi \n---\n include/net/netfilter/nf_dup_netdev.h | 13 +++++++++++++\n net/netfilter/nf_dup_netdev.c | 16 ----------------\n net/netfilter/nft_fwd_netdev.c | 7 +++++++\n 3 files changed, 20 insertions(+), 16 deletions(-)","diff":"diff --git a/include/net/netfilter/nf_dup_netdev.h b/include/net/netfilter/nf_dup_netdev.h\nindex b175d271aec9..609bcf422a9b 100644\n--- a/include/net/netfilter/nf_dup_netdev.h\n+++ b/include/net/netfilter/nf_dup_netdev.h\n@@ -3,10 +3,23 @@\n #define _NF_DUP_NETDEV_H_\n \n #include \n+#include \n+#include \n \n void nf_dup_netdev_egress(const struct nft_pktinfo *pkt, int oif);\n void nf_fwd_netdev_egress(const struct nft_pktinfo *pkt, int oif);\n \n+#define NF_RECURSION_LIMIT\t2\n+\n+static inline u8 *nf_get_nf_dup_skb_recursion(void)\n+{\n+#ifndef CONFIG_PREEMPT_RT\n+\treturn this_cpu_ptr(&softnet_data.xmit.nf_dup_skb_recursion);\n+#else\n+\treturn ¤t->net_xmit.nf_dup_skb_recursion;\n+#endif\n+}\n+\n struct nft_offload_ctx;\n struct nft_flow_rule;\n \ndiff --git a/net/netfilter/nf_dup_netdev.c b/net/netfilter/nf_dup_netdev.c\nindex fab8b9011098..a958a1b0c5be 100644\n--- a/net/netfilter/nf_dup_netdev.c\n+++ b/net/netfilter/nf_dup_netdev.c\n@@ -13,22 +13,6 @@\n #include \n #include \n \n-#define NF_RECURSION_LIMIT\t2\n-\n-#ifndef CONFIG_PREEMPT_RT\n-static u8 *nf_get_nf_dup_skb_recursion(void)\n-{\n-\treturn this_cpu_ptr(&softnet_data.xmit.nf_dup_skb_recursion);\n-}\n-#else\n-\n-static u8 *nf_get_nf_dup_skb_recursion(void)\n-{\n-\treturn ¤t->net_xmit.nf_dup_skb_recursion;\n-}\n-\n-#endif\n-\n static void nf_do_netdev_egress(struct sk_buff *skb, struct net_device *dev,\n \t\t\t\tenum nf_dev_hooks hook)\n {\ndiff --git a/net/netfilter/nft_fwd_netdev.c b/net/netfilter/nft_fwd_netdev.c\nindex 152a9fb4d23a..492bb599a499 100644\n--- a/net/netfilter/nft_fwd_netdev.c\n+++ b/net/netfilter/nft_fwd_netdev.c\n@@ -141,13 +141,20 @@ static void nft_fwd_neigh_eval(const struct nft_expr *expr,\n \t\tgoto out;\n \t}\n \n+\tif (*nf_get_nf_dup_skb_recursion() > NF_RECURSION_LIMIT) {\n+\t\tverdict = NF_DROP;\n+\t\tgoto out;\n+\t}\n+\n \tdev = dev_get_by_index_rcu(nft_net(pkt), oif);\n \tif (dev == NULL)\n \t\treturn;\n \n \tskb->dev = dev;\n \tskb_clear_tstamp(skb);\n+\t(*nf_get_nf_dup_skb_recursion())++;\n \tneigh_xmit(neigh_table, dev, addr, skb);\n+\t(*nf_get_nf_dup_skb_recursion())--;\n out:\n \tregs->verdict.code = verdict;\n }\n","prefixes":["v2"]}