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From: Andrey Konovalov <andreyknvl@google.com>
Newsgroups: linux.kernel
Subject: Re: net: heap out-of-bounds in fib6_clean_node/rt6_fill_node/fib6_age/fib6_prune_clone
Date: Thu, 20 Apr 2017 14:20:01 +0200
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References: <tgZlo-4ue-29@gated-at.bofh.it> <tirSi-2Tr-25@gated-at.bofh.it> <tislk-35L-15@gated-at.bofh.it> <tisOl-3ze-3@gated-at.bofh.it> <tithn-3Jt-21@gated-at.bofh.it> <titAK-46W-23@gated-at.bofh.it> <tiIT8-6v2-23@gated-at.bofh.it> <tpCfT-87G-3@gated-at.bofh.it> <tpDlE-r8-11@gated-at.bofh.it> <tpDOF-Ur-9@gated-at.bofh.it> <txIet-2fd-9@gated-at.bofh.it> <ty0l4-5yM-27@gated-at.bofh.it> <ty0uL-5Cb-41@gated-at.bofh.it> <ty7wd-1ki-7@gated-at.bofh.it> <ty7FT-1nw-3@gated-at.bofh.it> <tyfN8-6Do-3@gated-at.bofh.it>
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On Thu, Apr 20, 2017 at 10:35 AM, Dmitry Vyukov <dvyukov@google.com> wrote:
> On Thu, Apr 20, 2017 at 1:51 AM, David Ahern <dsa@cumulusnetworks.com> wrote:
>> On 4/19/17 5:47 PM, Cong Wang wrote:
>>> On Wed, Apr 19, 2017 at 9:12 AM, Andrey Konovalov <andreyknvl@google.com> wrote:
>>>>
>>>> Anyway, I just finished simplifying the reproducer. Give this one a try.
>>>
>>> Thanks for providing such a minimal reproducer!
>>>
>>> The following patch could fix this crash, but I am not 100% sure if we should
>>> just clear these bits or reject them with an errno.
>>>
>>> diff --git a/net/ipv6/route.c b/net/ipv6/route.c
>>> index 9db14189..cf524c2 100644
>>> --- a/net/ipv6/route.c
>>> +++ b/net/ipv6/route.c
>>> @@ -2086,7 +2086,7 @@ static struct rt6_info
>>> *ip6_route_info_create(struct fib6_config *cfg)
>>>         } else
>>>                 rt->rt6i_prefsrc.plen = 0;
>>>
>>> -       rt->rt6i_flags = cfg->fc_flags;
>>> +       rt->rt6i_flags = cfg->fc_flags & ~(RTF_PCPU | RTF_CACHE);
>>>
>>>  install_route:
>>>         rt->dst.dev = dev;
>>>
>>
>> I sent a patch returning EINVAL if RTF_PCPU is set in fc_flags
>
>
> Andrey, does it fix the other crashes?

No, still see them.

I'm working on reproducing those.