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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1114EC433E1 for ; Mon, 18 May 2020 17:39:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E4443207C4 for ; Mon, 18 May 2020 17:39:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589823574; bh=jptbGf47UtxIe6X7zV5uYiSn+4FsyqIgKhShjmDJwR8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=mvYG++dgxDRzNvZQuuB+i5COsqN4TnezAGLaV69CejPIFRAubma8CFcjwngQB+mbG AtZ6PVkEQjeSO3g9JtEu/IgkE3xaHcmOgkQYmcRwUpWT8MT+mWH/j4FU3YBz9hoZPZ 4pSgAMtNf5YHAMN/lHrkhSwNiD8KdTg1br1bBqAU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728837AbgERRje (ORCPT ); Mon, 18 May 2020 13:39:34 -0400 Received: from mail.kernel.org ([198.145.29.99]:34212 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728822AbgERRjb (ORCPT ); Mon, 18 May 2020 13:39:31 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id AD22C207C4; Mon, 18 May 2020 17:39:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589823571; bh=jptbGf47UtxIe6X7zV5uYiSn+4FsyqIgKhShjmDJwR8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=F73lNmLkmqr9AxJelr+GIkFWpOJ5turZS4pvF/5rORvAlR468Js+OnuCt0zAFHI87 HW1USDxms9oi4AVp3JlHLkcbRbrgp3XZ32AjeTwrfjGoZatCsQC2/b18OHMFuJKq0z jFmV4YQVa1aHw8MGUz1biMnIKiWX+d5ss8zHWzT8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andrey Konovalov , David Ahern , "David S. Miller" , "Nobuhiro Iwamatsu (CIP)" Subject: [PATCH 4.4 35/86] net: handle no dst on skb in icmp6_send Date: Mon, 18 May 2020 19:36:06 +0200 Message-Id: <20200518173457.623138564@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200518173450.254571947@linuxfoundation.org> References: <20200518173450.254571947@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: David Ahern commit 79dc7e3f1cd323be4c81aa1a94faa1b3ed987fb2 upstream. Andrey reported the following while fuzzing the kernel with syzkaller: kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] SMP KASAN Modules linked in: CPU: 0 PID: 3859 Comm: a.out Not tainted 4.9.0-rc6+ #429 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 task: ffff8800666d4200 task.stack: ffff880067348000 RIP: 0010:[] [] icmp6_send+0x5fc/0x1e30 net/ipv6/icmp.c:451 RSP: 0018:ffff88006734f2c0 EFLAGS: 00010206 RAX: ffff8800666d4200 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: dffffc0000000000 RDI: 0000000000000018 RBP: ffff88006734f630 R08: ffff880064138418 R09: 0000000000000003 R10: dffffc0000000000 R11: 0000000000000005 R12: 0000000000000000 R13: ffffffff84e7e200 R14: ffff880064138484 R15: ffff8800641383c0 FS: 00007fb3887a07c0(0000) GS:ffff88006cc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000000 CR3: 000000006b040000 CR4: 00000000000006f0 Stack: ffff8800666d4200 ffff8800666d49f8 ffff8800666d4200 ffffffff84c02460 ffff8800666d4a1a 1ffff1000ccdaa2f ffff88006734f498 0000000000000046 ffff88006734f440 ffffffff832f4269 ffff880064ba7456 0000000000000000 Call Trace: [] icmpv6_param_prob+0x2c/0x40 net/ipv6/icmp.c:557 [< inline >] ip6_tlvopt_unknown net/ipv6/exthdrs.c:88 [] ip6_parse_tlv+0x555/0x670 net/ipv6/exthdrs.c:157 [] ipv6_parse_hopopts+0x199/0x460 net/ipv6/exthdrs.c:663 [] ipv6_rcv+0xfa3/0x1dc0 net/ipv6/ip6_input.c:191 ... icmp6_send / icmpv6_send is invoked for both rx and tx paths. In both cases the dst->dev should be preferred for determining the L3 domain if the dst has been set on the skb. Fallback to the skb->dev if it has not. This covers the case reported here where icmp6_send is invoked on Rx before the route lookup. Fixes: 5d41ce29e ("net: icmp6_send should use dst dev to determine L3 domain") Reported-by: Andrey Konovalov Signed-off-by: David Ahern Signed-off-by: David S. Miller Signed-off-by: Nobuhiro Iwamatsu (CIP) Signed-off-by: Greg Kroah-Hartman --- net/ipv6/icmp.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/net/ipv6/icmp.c +++ b/net/ipv6/icmp.c @@ -445,8 +445,10 @@ static void icmp6_send(struct sk_buff *s if (__ipv6_addr_needs_scope_id(addr_type)) iif = skb->dev->ifindex; - else - iif = l3mdev_master_ifindex(skb_dst(skb)->dev); + else { + dst = skb_dst(skb); + iif = l3mdev_master_ifindex(dst ? dst->dev : skb->dev); + } /* * Must not send error if the source does not uniquely