From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C02A8332EA7; Sat, 30 May 2026 17:23:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780161803; cv=none; b=uu8tZBpepZlwqoXG1htvX0K2y20KZNvC85x1lRoQdd1QH7b3QQM/G94ofdgYS7Zm6vyG8m9+FpWvJsfiPai/eklzVmnaKA/68U+0DhjFZeTIA7CRuE0evGtanuN5chZAk8Vzl1BW69cTJlVJ7MA8A8Mmg1HFLw/5LyUeiwm2/pg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780161803; c=relaxed/simple; bh=is1Q/Usyb93BXvRFZ6BsXwGONksQPgUjDF3oZxs3HJ8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HA93n9pNIbNPJNZZ155d0E3Bjh//4F3n8ES8BM0ozEYMFTyWveO3x+SVALpAn78oNmcx6NiUnYiZbsNHnu9z3ksV5lAYagHNMRXBB1BiPrksQUNq1u3n0Lor73Cs2sMmwmfiMVZv+1tDzWI41BBaYKtvRi4UjRdPTiLq1NyCS/Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=oC1W2vxl; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="oC1W2vxl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0B4361F00893; Sat, 30 May 2026 17:23:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780161802; bh=gyJQQzviy6VUoZc0Tthq0m/3e9fw76y4GKTO6rMhfGM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=oC1W2vxlYVGh/5XtLWu2jRBHR5h9JA7acSmfMCz+IBA1848MUC6dhTJyruXJ9Ngwr 09UN2lKWKRq52NO1AJzpHUwse5h4/lWnGz6mlcvp8xCnaKMbstlp0CjceNx0Ih58ju 9NRPM20a0GWkcceNyt6AecNjSE2AqzkTNi0VqtlI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Weiming Shi , Florian Westphal , Pablo Neira Ayuso , Xiang Mei , Fernando Fernandez Mancera , Sasha Levin Subject: [PATCH 6.1 701/969] netfilter: nfnetlink_osf: fix divide-by-zero in OSF_WSS_MODULO Date: Sat, 30 May 2026 18:03:45 +0200 Message-ID: <20260530160319.875626463@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260530160300.485627683@linuxfoundation.org> References: <20260530160300.485627683@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Xiang Mei [ Upstream commit 2195574dc6d9017d32ac346987e12659f931d932 ] nf_osf_match_one() computes ctx->window % f->wss.val in the OSF_WSS_MODULO branch with no guard for f->wss.val == 0. A CAP_NET_ADMIN user can add such a fingerprint via nfnetlink; a subsequent matching TCP SYN divides by zero and panics the kernel. Reject the bogus fingerprint in nfnl_osf_add_callback() above the per-option for-loop. f->wss is per-fingerprint, not per-option, so the check must run regardless of f->opt_num (including 0). Also reject wss.wc >= OSF_WSS_MAX; nf_osf_match_one() already treats that as "should not happen". Crash: Oops: divide error: 0000 [#1] SMP KASAN NOPTI RIP: 0010:nf_osf_match_one (net/netfilter/nfnetlink_osf.c:98) Call Trace: nf_osf_match (net/netfilter/nfnetlink_osf.c:220) xt_osf_match_packet (net/netfilter/xt_osf.c:32) ipt_do_table (net/ipv4/netfilter/ip_tables.c:348) nf_hook_slow (net/netfilter/core.c:622) ip_local_deliver (net/ipv4/ip_input.c:265) ip_rcv (include/linux/skbuff.h:1162) __netif_receive_skb_one_core (net/core/dev.c:6181) process_backlog (net/core/dev.c:6642) __napi_poll (net/core/dev.c:7710) net_rx_action (net/core/dev.c:7945) handle_softirqs (kernel/softirq.c:622) Fixes: 11eeef41d5f6 ("netfilter: passive OS fingerprint xtables match") Reported-by: Weiming Shi Suggested-by: Florian Westphal Suggested-by: Pablo Neira Ayuso Signed-off-by: Xiang Mei Reviewed-by: Fernando Fernandez Mancera Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin --- net/netfilter/nfnetlink_osf.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/netfilter/nfnetlink_osf.c b/net/netfilter/nfnetlink_osf.c index da9d5d6de98f4..000a5c280ef96 100644 --- a/net/netfilter/nfnetlink_osf.c +++ b/net/netfilter/nfnetlink_osf.c @@ -320,6 +320,10 @@ static int nfnl_osf_add_callback(struct sk_buff *skb, if (f->opt_num > ARRAY_SIZE(f->opt)) return -EINVAL; + if (f->wss.wc >= OSF_WSS_MAX || + (f->wss.wc == OSF_WSS_MODULO && f->wss.val == 0)) + return -EINVAL; + for (i = 0; i < f->opt_num; i++) { if (!f->opt[i].length || f->opt[i].length > MAX_IPOPTLEN) return -EINVAL; -- 2.53.0