{"id":2223685,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2223685/?format=json","web_url":"http://patchwork.ozlabs.org/project/netfilter-devel/patch/20260416013101.221555-5-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":"<20260416013101.221555-5-pablo@netfilter.org>","date":"2026-04-16T01:30:51","name":"[net,04/14] netfilter: nfnetlink_osf: fix divide-by-zero in OSF_WSS_MODULO","commit_ref":null,"pull_url":null,"state":"superseded","archived":true,"hash":"e86eb5b7f50dfb83611738c26422db9076f63311","submitter":{"id":1315,"url":"http://patchwork.ozlabs.org/api/1.1/people/1315/?format=json","name":"Pablo Neira Ayuso","email":"pablo@netfilter.org"},"delegate":{"id":11902,"url":"http://patchwork.ozlabs.org/api/1.1/users/11902/?format=json","username":"strlen","first_name":"Florian","last_name":"Westphal","email":"fw@strlen.de"},"mbox":"http://patchwork.ozlabs.org/project/netfilter-devel/patch/20260416013101.221555-5-pablo@netfilter.org/mbox/","series":[{"id":500063,"url":"http://patchwork.ozlabs.org/api/1.1/series/500063/?format=json","web_url":"http://patchwork.ozlabs.org/project/netfilter-devel/list/?series=500063","date":"2026-04-16T01:30:47","name":"[net,01/14] netfilter: nft_fwd_netdev: use recursion counter in neigh egress path","version":1,"mbox":"http://patchwork.ozlabs.org/series/500063/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2223685/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2223685/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=I4Xrco8g;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c09:e001:a7::12fc:5321; helo=sto.lore.kernel.org;\n envelope-from=netfilter-devel+bounces-11950-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=\"I4Xrco8g\"","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 sto.lore.kernel.org (sto.lore.kernel.org\n [IPv6:2600:3c09:e001:a7::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 4fx0qJ5ch0z1yG9\n\tfor ; Thu, 16 Apr 2026 11:31:56 +1000 (AEST)","from smtp.subspace.kernel.org (conduit.subspace.kernel.org\n [100.90.174.1])\n\tby sto.lore.kernel.org (Postfix) with ESMTP id 72A6A3072D24\n\tfor ; Thu, 16 Apr 2026 01:31:27 +0000 (UTC)","from localhost.localdomain (localhost.localdomain [127.0.0.1])\n\tby smtp.subspace.kernel.org (Postfix) with ESMTP id 9610B24293C;\n\tThu, 16 Apr 2026 01:31:16 +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 AEE6123ABB9;\n\tThu, 16 Apr 2026 01:31:14 +0000 (UTC)","from localhost.localdomain (mail-agni [217.70.190.124])\n\tby mail.netfilter.org (Postfix) with ESMTPSA id 7E6396017D;\n\tThu, 16 Apr 2026 03:31:12 +0200 (CEST)"],"ARC-Seal":"i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116;\n\tt=1776303076; cv=none;\n b=ukUT4zBHH4GCAljRC82uj/aCFMkXoUGjM1E7NbywlxJu9kcg3/gQwn0cTv2ZRdwpSQCnKRUzB88RZco08bYoefS1A6Z2Bg36qKhT/onlooAf9sNW+RDPfFlbrAdFAJcytoS+Cq35anzvfpRND+sIH/0fGrBKQdoAoU4aS77EWQI=","ARC-Message-Signature":"i=1; a=rsa-sha256; d=subspace.kernel.org;\n\ts=arc-20240116; t=1776303076; c=relaxed/simple;\n\tbh=PawOKsjU/i0MTF68zbUb+VsSAv0gXGWmxITDx7vkR6k=;\n\th=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References:\n\t MIME-Version;\n b=kmULh/Y1rQ/jbzIoUO0XqYtZcAx5Q1nUJFY7rrRPBQ3hhz0vum7tzHFXIu14tcK8MqbSF09huWVziV5NqDfnvtRoEbfkELk1zv4iBGGBBaHvASs+60LNguFI+I12kVjzjwCfaVahP0PUboKoxHMrrX/PQxjoIBzaLU21A1h1DIM=","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=I4Xrco8g; 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=1776303073;\n\tbh=0HS0505hGdVF8P/vAEeHwqgAoOpv+wYp7KMbrpsv3RI=;\n\th=From:To:Cc:Subject:Date:In-Reply-To:References:From;\n\tb=I4Xrco8gKpG1A+Zqd4h9vxB2wpbPVXl6EnestYRhk5rJQL1eGnmycuetQMOa4veI/\n\t FSx2gJpT36wZFrbJaUOE49J4LA7sz2dj2a9+ZN0xcpQW9dgWPwbcNgWuEqzAF+y2rb\n\t IPYJPUzFMhv1gyoPT2XPYzXG9ClKGgHaxD0daq4zqacdsauF+wsX9eMqFcSR1EkAKn\n\t NueN2nwRncHd9nMK6DdyWFM6hKBrd+38VDIRngm/tqVIqIHlPyXpKGPc5rrU2gslz5\n\t WH8b0H0k0lmG4p2OgSvKxSb8Jid6Uw6ke8ptx2GtIk3EMbl29ZvhxGHY4aB45/kLZP\n\t W9fZG+FJ/NKFA==","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 04/14] netfilter: nfnetlink_osf: fix divide-by-zero in\n OSF_WSS_MODULO","Date":"Thu, 16 Apr 2026 03:30:51 +0200","Message-ID":"<20260416013101.221555-5-pablo@netfilter.org>","X-Mailer":"git-send-email 2.47.3","In-Reply-To":"<20260416013101.221555-1-pablo@netfilter.org>","References":"<20260416013101.221555-1-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":"From: Xiang Mei \n\nnf_osf_match_one() computes ctx->window % f->wss.val in the\nOSF_WSS_MODULO branch with no guard for f->wss.val == 0. A\nCAP_NET_ADMIN user can add such a fingerprint via nfnetlink; a\nsubsequent matching TCP SYN divides by zero and panics the kernel.\n\nReject the bogus fingerprint in nfnl_osf_add_callback() above the\nper-option for-loop. f->wss is per-fingerprint, not per-option, so\nthe check must run regardless of f->opt_num (including 0). Also\nreject wss.wc >= OSF_WSS_MAX; nf_osf_match_one() already treats that\nas \"should not happen\".\n\nCrash:\n Oops: divide error: 0000 [#1] SMP KASAN NOPTI\n RIP: 0010:nf_osf_match_one (net/netfilter/nfnetlink_osf.c:98)\n Call Trace:\n \n nf_osf_match (net/netfilter/nfnetlink_osf.c:220)\n xt_osf_match_packet (net/netfilter/xt_osf.c:32)\n ipt_do_table (net/ipv4/netfilter/ip_tables.c:348)\n nf_hook_slow (net/netfilter/core.c:622)\n ip_local_deliver (net/ipv4/ip_input.c:265)\n ip_rcv (include/linux/skbuff.h:1162)\n __netif_receive_skb_one_core (net/core/dev.c:6181)\n process_backlog (net/core/dev.c:6642)\n __napi_poll (net/core/dev.c:7710)\n net_rx_action (net/core/dev.c:7945)\n handle_softirqs (kernel/softirq.c:622)\n\nFixes: 11eeef41d5f6 (\"netfilter: passive OS fingerprint xtables match\")\nReported-by: Weiming Shi \nSuggested-by: Florian Westphal \nSuggested-by: Pablo Neira Ayuso \nSigned-off-by: Xiang Mei \nReviewed-by: Fernando Fernandez Mancera \nSigned-off-by: Pablo Neira Ayuso \n---\n net/netfilter/nfnetlink_osf.c | 4 ++++\n 1 file changed, 4 insertions(+)","diff":"diff --git a/net/netfilter/nfnetlink_osf.c b/net/netfilter/nfnetlink_osf.c\nindex 45d9ad231a92..70172ca07858 100644\n--- a/net/netfilter/nfnetlink_osf.c\n+++ b/net/netfilter/nfnetlink_osf.c\n@@ -320,6 +320,10 @@ static int nfnl_osf_add_callback(struct sk_buff *skb,\n \tif (f->opt_num > ARRAY_SIZE(f->opt))\n \t\treturn -EINVAL;\n \n+\tif (f->wss.wc >= OSF_WSS_MAX ||\n+\t (f->wss.wc == OSF_WSS_MODULO && f->wss.val == 0))\n+\t\treturn -EINVAL;\n+\n \tfor (i = 0; i < f->opt_num; i++) {\n \t\tif (!f->opt[i].length || f->opt[i].length > MAX_IPOPTLEN)\n \t\t\treturn -EINVAL;\n","prefixes":["net","04/14"]}