From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH net v2] ipv6: remove null_entry before adding default
 route
Date: Tue, 09 Jan 2018 12:34:36 -0500 (EST)
Message-ID: <20180109.123436.874984116978793472.davem@davemloft.net>
References: <20180108183400.206017-1-tracywwnj@gmail.com>
Mime-Version: 1.0
Content-Type: Text/Plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Cc: netdev@vger.kernel.org, kafai@fb.com, edumazet@google.com
To: weiwan@google.com
Return-path: <netdev-owner@vger.kernel.org>
Received: from shards.monkeyblade.net ([184.105.139.130]:34940 "EHLO
        shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1755356AbeAIReh (ORCPT
        <rfc822;netdev@vger.kernel.org>); Tue, 9 Jan 2018 12:34:37 -0500
In-Reply-To: <20180108183400.206017-1-tracywwnj@gmail.com>
Sender: netdev-owner@vger.kernel.org
List-ID: <netdev.vger.kernel.org>

From: Wei Wang <weiwan@google.com>
Date: Mon,  8 Jan 2018 10:34:00 -0800

> From: Wei Wang <weiwan@google.com>
> 
> In the current code, when creating a new fib6 table, tb6_root.leaf gets
> initialized to net->ipv6.ip6_null_entry.
> If a default route is being added with rt->rt6i_metric = 0xffffffff,
> fib6_add() will add this route after net->ipv6.ip6_null_entry. As
> null_entry is shared, it could cause problem.
> 
> In order to fix it, set fn->leaf to NULL before calling
> fib6_add_rt2node() when trying to add the first default route.
> And reset fn->leaf to null_entry when adding fails or when deleting the
> last default route.
> 
> syzkaller reported the following issue which is fixed by this commit:
 ...
> Reported-by: syzbot <syzkaller@googlegroups.com>
> Fixes: 66f5d6ce53e6 ("ipv6: replace rwlock with rcu and spinlock in fib6_table")
> Signed-off-by: Wei Wang <weiwan@google.com>

Applied, thank you.