Re: [Patch net v3] ipv6: check for ip6_null_entry in __ip6_del_rt_siblings()

[David Miller <davem@davemloft.net>]

From: David Ahern <dsa@cumulusnetworks.com>
Date: Wed, 1 Mar 2017 15:03:45 -0800

> On 2/27/17 4:07 PM, Cong Wang wrote:
>> Andrey reported a NULL pointer deref bug in ipv6_route_ioctl()
>> -> ip6_route_del() -> __ip6_del_rt_siblings() code path. This is
>> because ip6_null_entry is returned in this path since ip6_null_entry
>> is kinda default for a ipv6 route table root node. Quote from
>> David Ahern:
>> 
>>  ip6_null_entry is the root of all ipv6 fib tables making it integrated
>>  into the table ...
>> 
>> We should ignore any attempt of trying to delete it, like we do in
>> __ip6_del_rt() path and several others.
>> 
>> Reported-by: Andrey Konovalov <andreyknvl@google.com>
>> Fixes: 0ae8133586ad ("net: ipv6: Allow shorthand delete of all nexthops in multipath route")
>> Cc: David Ahern <dsa@cumulusnetworks.com>
>> Cc: Eric Dumazet <eric.dumazet@gmail.com>
>> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
>> ---
>>  net/ipv6/route.c | 14 +++++++++-----
>>  1 file changed, 9 insertions(+), 5 deletions(-)
> 
> 
> Acked-by: David Ahern <dsa@cumulusnetworks.com>

Applied, thanks.