From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A7B0DC433EF for ; Mon, 1 Nov 2021 22:15:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8B35860F56 for ; Mon, 1 Nov 2021 22:15:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232336AbhKAWSY (ORCPT ); Mon, 1 Nov 2021 18:18:24 -0400 Received: from mail.netfilter.org ([217.70.188.207]:59202 "EHLO mail.netfilter.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232176AbhKAWSO (ORCPT ); Mon, 1 Nov 2021 18:18:14 -0400 Received: from localhost.localdomain (unknown [78.30.32.163]) by mail.netfilter.org (Postfix) with ESMTPSA id 0637A63F55; Mon, 1 Nov 2021 23:13:46 +0100 (CET) From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Cc: davem@davemloft.net, netdev@vger.kernel.org, kuba@kernel.org Subject: [PATCH net 1/2] netfilter: nfnetlink_queue: fix OOB when mac header was cleared Date: Mon, 1 Nov 2021 23:15:27 +0100 Message-Id: <20211101221528.236114-2-pablo@netfilter.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20211101221528.236114-1-pablo@netfilter.org> References: <20211101221528.236114-1-pablo@netfilter.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org From: Florian Westphal On 64bit platforms the MAC header is set to 0xffff on allocation and also when a helper like skb_unset_mac_header() is called. dev_parse_header may call skb_mac_header() which assumes valid mac offset: BUG: KASAN: use-after-free in eth_header_parse+0x75/0x90 Read of size 6 at addr ffff8881075a5c05 by task nf-queue/1364 Call Trace: memcpy+0x20/0x60 eth_header_parse+0x75/0x90 __nfqnl_enqueue_packet+0x1a61/0x3380 __nf_queue+0x597/0x1300 nf_queue+0xf/0x40 nf_hook_slow+0xed/0x190 nf_hook+0x184/0x440 ip_output+0x1c0/0x2a0 nf_reinject+0x26f/0x700 nfqnl_recv_verdict+0xa16/0x18b0 nfnetlink_rcv_msg+0x506/0xe70 The existing code only works if the skb has a mac header. Fixes: 2c38de4c1f8da7 ("netfilter: fix looped (broad|multi)cast's MAC handling") Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/netfilter/nfnetlink_queue.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c index 4c3fbaaeb103..4acc4b8e9fe5 100644 --- a/net/netfilter/nfnetlink_queue.c +++ b/net/netfilter/nfnetlink_queue.c @@ -560,7 +560,7 @@ nfqnl_build_packet_message(struct net *net, struct nfqnl_instance *queue, goto nla_put_failure; if (indev && entskb->dev && - entskb->mac_header != entskb->network_header) { + skb_mac_header_was_set(entskb)) { struct nfqnl_msg_packet_hw phw; int len; -- 2.30.2