From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.netfilter.org (mail.netfilter.org [217.70.190.124]) (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 B189C3BD246; Thu, 16 Apr 2026 13:15:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.190.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776345305; cv=none; b=Ww9l7LK91gHr+FZacMXaGh4HPiR/sZ1L3R6/5R9BL/oPA/Pt2AHhSaa3pMV3XqRLuIzSkvK1vW4jjzsAJeUwaP+ioK3Ymt/udrMwVrb5/soz8FDhy413pBJDHPTNbnDD1sXDJU/ZsHzp14908SVauWImnoM5nQlwca1E8JNEXAc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776345305; c=relaxed/simple; bh=E+TqY3nur+I/j7EktcUsc/tC9j0NrLrhL7r3Z7S4k0Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=iCtaNXMtoZq415nenhB0EQoKhwgydXLHV6Y3gtMDBK4b60vHTTg5BtFp1HhWfX/eA3E1vGPwu30V6k9YumVvfIxBkuoqExXYaJaR3Lhxoj0XcOoQzp76vI+DkOTmLB+o/EnJLid9IDxQy7wnNKdbow9dPEggR9z5lAPM7bak+Y0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org; spf=pass smtp.mailfrom=netfilter.org; dkim=pass (2048-bit key) header.d=netfilter.org header.i=@netfilter.org header.b=NgZPu9kl; arc=none smtp.client-ip=217.70.190.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=netfilter.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=netfilter.org header.i=@netfilter.org header.b="NgZPu9kl" Received: from localhost.localdomain (mail-agni [217.70.190.124]) by mail.netfilter.org (Postfix) with ESMTPSA id 51F4060253; Thu, 16 Apr 2026 15:15:01 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=netfilter.org; s=2025; t=1776345301; bh=UKA+A3aFYBFFgnZcbNAbiR56Du+bLjEnS3Riajgl8fg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NgZPu9klyq8xsRfNTXWB/oar9AdUGeNFczkn5IWtOiSMtBhJdeE8Ft46z1BpGeiSv 9JoNTyWRavFYK4QSbXW61SPS2maOkzqC2XEXKOyJqZkMKf8KrmesV5ii32QbmTb/PS GnBJYR8Hib1iYhom2JzprK7CyHQKRBDzWriLgnppWPjMVNz51WlynUa9FopsVGSYQJ BPMatb7MOsm09gSGNz2kiZmg+qTd+8o0PNuFYSZj72fuPj9SRBLz8cYfDeSYEoKcTC sc73LIrCE1jrRzSd7JSOeNk4QmDjesac0EOihgriHwbocZ4Jk+qfCle0+BRSf8nAYt AnRas55T9RX7g== From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Cc: davem@davemloft.net, netdev@vger.kernel.org, kuba@kernel.org, pabeni@redhat.com, edumazet@google.com, fw@strlen.de, horms@kernel.org Subject: [PATCH net 01/11] netfilter: arp_tables: fix IEEE1394 ARP payload parsing in arp_packet_match() Date: Thu, 16 Apr 2026 15:14:43 +0200 Message-ID: <20260416131453.308611-2-pablo@netfilter.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260416131453.308611-1-pablo@netfilter.org> References: <20260416131453.308611-1-pablo@netfilter.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Weiming Shi arp_packet_match() unconditionally parses the ARP payload assuming two hardware addresses are present (source and target). However, IPv4-over-IEEE1394 ARP (RFC 2734) omits the target hardware address field, and arp_hdr_len() already accounts for this by returning a shorter length for ARPHRD_IEEE1394 devices. As a result, on IEEE1394 interfaces arp_packet_match() advances past a nonexistent target hardware address and reads the wrong bytes for both the target device address comparison and the target IP address. This causes arptables rules to match against garbage data, leading to incorrect filtering decisions: packets that should be accepted may be dropped and vice versa. The ARP stack in net/ipv4/arp.c (arp_create and arp_process) already handles this correctly by skipping the target hardware address for ARPHRD_IEEE1394. Apply the same pattern to arp_packet_match(). [ Pablo has mangled this patch to include Simon Horman's suggestions ] Fixes: 6752c8db8e0c ("firewire net, ipv4 arp: Extend hardware address and remove driver-level packet inspection.") Reported-by: Xiang Mei Signed-off-by: Weiming Shi Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/ipv4/netfilter/arp_tables.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c index 1cdd9c28ab2d..a7a56890b5b5 100644 --- a/net/ipv4/netfilter/arp_tables.c +++ b/net/ipv4/netfilter/arp_tables.c @@ -110,13 +110,21 @@ static inline int arp_packet_match(const struct arphdr *arphdr, arpptr += dev->addr_len; memcpy(&src_ipaddr, arpptr, sizeof(u32)); arpptr += sizeof(u32); - tgt_devaddr = arpptr; - arpptr += dev->addr_len; + + if (IS_ENABLED(CONFIG_FIREWIRE_NET) && dev->type == ARPHRD_IEEE1394) { + tgt_devaddr = NULL; + } else { + tgt_devaddr = arpptr; + arpptr += dev->addr_len; + } memcpy(&tgt_ipaddr, arpptr, sizeof(u32)); if (NF_INVF(arpinfo, ARPT_INV_SRCDEVADDR, arp_devaddr_compare(&arpinfo->src_devaddr, src_devaddr, - dev->addr_len)) || + dev->addr_len))) + return 0; + + if (tgt_devaddr && NF_INVF(arpinfo, ARPT_INV_TGTDEVADDR, arp_devaddr_compare(&arpinfo->tgt_devaddr, tgt_devaddr, dev->addr_len))) -- 2.47.3