netdev - Re: [PATCHv2 net] ipv6: make ip6_create_rt_rcu return ip6_null

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <469a581e-9ea9-6c38-a88f-04768e8971bc@gmail.com>
Date:   Wed, 20 Mar 2019 08:41:54 +0100
From:   David Ahern <dsahern@...il.com>
To:     Xin Long <lucien.xin@...il.com>,
        network dev <netdev@...r.kernel.org>
Cc:     davem@...emloft.net, Wei Wang <weiwan@...gle.com>,
        Paolo Abeni <pabeni@...hat.com>
Subject: Re: [PATCHv2 net] ipv6: make ip6_create_rt_rcu return ip6_null_entry
 instead of NULL

On 3/20/19 7:45 AM, Xin Long wrote:
> Jianlin reported a crash:
> 
>   [  381.484332] BUG: unable to handle kernel NULL pointer dereference at 0000000000000068
>   [  381.619802] RIP: 0010:fib6_rule_lookup+0xa3/0x160
>   [  382.009615] Call Trace:
>   [  382.020762]  <IRQ>
>   [  382.030174]  ip6_route_redirect.isra.52+0xc9/0xf0
>   [  382.050984]  ip6_redirect+0xb6/0xf0
>   [  382.066731]  icmpv6_notify+0xca/0x190
>   [  382.083185]  ndisc_redirect_rcv+0x10f/0x160
>   [  382.102569]  ndisc_rcv+0xfb/0x100
>   [  382.117725]  icmpv6_rcv+0x3f2/0x520
>   [  382.133637]  ip6_input_finish+0xbf/0x460
>   [  382.151634]  ip6_input+0x3b/0xb0
>   [  382.166097]  ipv6_rcv+0x378/0x4e0
> 
> It was caused by the lookup function __ip6_route_redirect() returns NULL in
> fib6_rule_lookup() when ip6_create_rt_rcu() returns NULL.
> 
> So we fix it by simply making ip6_create_rt_rcu() return ip6_null_entry
> instead of NULL.
> 
> v1->v2:
>   - move down 'fallback:' to make it more readable.
> 
> Fixes: e873e4b9cc7e ("ipv6: use fib6_info_hold_safe() when necessary")
> Reported-by: Jianlin Shi <jishi@...hat.com>
> Suggested-by: Paolo Abeni <pabeni@...hat.com>
> Signed-off-by: Xin Long <lucien.xin@...il.com>
> ---
>  net/ipv6/route.c | 18 ++++++++++--------
>  1 file changed, 10 insertions(+), 8 deletions(-)
> 

Reviewed-by: David Ahern <dsahern@...il.com>