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Date:   Sat, 22 Jun 2019 16:51:11 -0700 (PDT)
Message-Id: <20190622.165111.1722448155363637012.davem@davemloft.net>
To:     idosch@idosch.org
Cc:     netdev@vger.kernel.org, dsahern@gmail.com, mlxsw@mellanox.com,
        idosch@mellanox.com
Subject: Re: [PATCH net-next v2] ipv6: Error when route does not have any
 valid nexthops
From:   David Miller <davem@davemloft.net>
In-Reply-To: <20190620091021.18210-1-idosch@idosch.org>
References: <20190620091021.18210-1-idosch@idosch.org>
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From: Ido Schimmel <idosch@idosch.org>
Date: Thu, 20 Jun 2019 12:10:21 +0300

> From: Ido Schimmel <idosch@mellanox.com>
> 
> When user space sends invalid information in RTA_MULTIPATH, the nexthop
> list in ip6_route_multipath_add() is empty and 'rt_notif' is set to
> NULL.
> 
> The code that emits the in-kernel notifications does not check for this
> condition, which results in a NULL pointer dereference [1].
> 
> Fix this by bailing earlier in the function if the parsed nexthop list
> is empty. This is consistent with the corresponding IPv4 code.
> 
> v2:
> * Check if parsed nexthop list is empty and bail with extack set
> 
> [1]
 ...
> 
> Reported-by: syzbot+382566d339d52cd1a204@syzkaller.appspotmail.com
> Fixes: ebee3cad835f ("ipv6: Add IPv6 multipath notifications for add / replace")
> Signed-off-by: Ido Schimmel <idosch@mellanox.com>

Applied.