From patchwork Sat Apr 18 10:06:33 2026 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Westphal X-Patchwork-Id: 2224762 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=2600:3c0a:e001:db::12fc:5321; helo=sea.lore.kernel.org; envelope-from=netfilter-devel+bounces-12016-incoming=patchwork.ozlabs.org@vger.kernel.org; receiver=patchwork.ozlabs.org) Received: from sea.lore.kernel.org (sea.lore.kernel.org [IPv6:2600:3c0a:e001:db::12fc:5321]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature ECDSA (secp384r1) server-digest SHA384) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4fyS9J5ss5z1yDF for ; Sat, 18 Apr 2026 20:07:32 +1000 (AEST) Received: from smtp.subspace.kernel.org (conduit.subspace.kernel.org [100.90.174.1]) by sea.lore.kernel.org (Postfix) with ESMTP id 5C54F303028C for ; Sat, 18 Apr 2026 10:06:58 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id D600F34216C; Sat, 18 Apr 2026 10:06:57 +0000 (UTC) X-Original-To: netfilter-devel@vger.kernel.org Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [91.216.245.30]) (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 DF40D72623 for ; Sat, 18 Apr 2026 10:06:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.216.245.30 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776506817; cv=none; b=XYuPMJnUA2vaCElr63/CHCAhtyTKD7soKUnkvzvuUHOCRM5EmR79GT+0SGgckIHAbsrCNv3Juw6DGXykNma+1hj2zeIJG7pgdbmDw8SARNBjxVMY3k1YYI8KUD8PD8w/7G6+308UnQUwEUfTwh6fys6OcK3P4SCX1QWiHIkxTS4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776506817; c=relaxed/simple; bh=VdnmGSCh5z8bjiqo+v+CDQMa8rl0+1bUVIbATHTA0Pg=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=e5KAGsTnm56ROq57F3adXJTf5xhB69X92egApwRUwlOrnA3cX8cTaUfCM6vDLn8SUBU3eWHmc21rWsV8/+khK624kLHKBjOvuSq5cXClBvoU5WLqglPNafZ4G46Gbrv8Oycwh4xQ+iA5yYcbVLSPCJvrQ1nyGKTFpufASMf+Nnw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=strlen.de; spf=pass smtp.mailfrom=Chamillionaire.breakpoint.cc; arc=none smtp.client-ip=91.216.245.30 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=strlen.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=Chamillionaire.breakpoint.cc Received: by Chamillionaire.breakpoint.cc (Postfix, from userid 1003) id 9499C606C8; Sat, 18 Apr 2026 12:06:53 +0200 (CEST) From: Florian Westphal To: Cc: Florian Westphal Subject: [PATCH nf v2] netfilter: arp_tables: fix IEEE1394 ARP payload mangling Date: Sat, 18 Apr 2026 12:06:33 +0200 Message-ID: <20260418100641.60660-1-fw@strlen.de> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: netfilter-devel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 sashiko.dev noticed that similar bug pattern exists in arpt_mangle: "IEEE1394 ARP payloads omit the target hardware address, advancing arpptr by hln after the source IP address skips over the actual target IP address." Apply similar fix: If we're asked to mangle what doesn't exist, drop the packet. Fixes: 6752c8db8e0c ("firewire net, ipv4 arp: Extend hardware address and remove driver-level packet inspection.") Signed-off-by: Florian Westphal --- v2: Just check ar_hrd. I do not know why the arp_tables.c change used dev->type instead. Also NOONE uses this feature and we could even completely ignore it, there is no crash and users can already use arptables to skip such frames. IOW, from a certain POV the report *IS* bullshit. I propose we keep these patches back to focus on real bugs instead, theer are plenty enough as-is. net/ipv4/netfilter/arpt_mangle.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/net/ipv4/netfilter/arpt_mangle.c b/net/ipv4/netfilter/arpt_mangle.c index a4e07e5e9c11..476369567231 100644 --- a/net/ipv4/netfilter/arpt_mangle.c +++ b/net/ipv4/netfilter/arpt_mangle.c @@ -13,6 +13,7 @@ static unsigned int target(struct sk_buff *skb, const struct xt_action_param *par) { const struct arpt_mangle *mangle = par->targinfo; + bool has_tgt_devaddr = true; const struct arphdr *arp; unsigned char *arpptr; int pln, hln; @@ -39,13 +40,22 @@ target(struct sk_buff *skb, const struct xt_action_param *par) memcpy(arpptr, &mangle->u_s.src_ip, pln); } arpptr += pln; + + if (arp->ar_hrd == htons(ARPHRD_IEEE1394)) + has_tgt_devaddr = false; + if (mangle->flags & ARPT_MANGLE_TDEV) { + if (!has_tgt_devaddr) + return NF_DROP; + if (ARPT_DEV_ADDR_LEN_MAX < hln || (arpptr + hln > skb_tail_pointer(skb))) return NF_DROP; memcpy(arpptr, mangle->tgt_devaddr, hln); } - arpptr += hln; + if (has_tgt_devaddr) + arpptr += hln; + if (mangle->flags & ARPT_MANGLE_TIP) { if (ARPT_MANGLE_ADDR_LEN_MAX < pln || (arpptr + pln > skb_tail_pointer(skb)))