netdev - Re: [PATCH net-next 2/2] ipv6: fix blackhole routes

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] [day] [month] [year] [list]

Message-ID: <b35c478a-8772-4391-b9dc-db981f34edc9@kernel.org>
Date: Thu, 13 Feb 2025 08:49:27 -0700
From: David Ahern <dsahern@...nel.org>
To: Stanislav Fomichev <stfomichev@...il.com>,
 Eric Dumazet <edumazet@...gle.com>
Cc: Nicolas Dichtel <nicolas.dichtel@...nd.com>,
 "David S . Miller" <davem@...emloft.net>, Jakub Kicinski <kuba@...nel.org>,
 Paolo Abeni <pabeni@...hat.com>, netdev@...r.kernel.org,
 Paul Ripke <stix@...gle.com>, Simon Horman <horms@...nel.org>,
 eric.dumazet@...il.com
Subject: Re: [PATCH net-next 2/2] ipv6: fix blackhole routes

On 2/12/25 7:30 PM, Stanislav Fomichev wrote:
> On 02/12, Eric Dumazet wrote:
>> On Wed, Feb 12, 2025 at 7:00 PM David Ahern <dsahern@...nel.org> wrote:
>>>
>>> On 2/12/25 9:43 AM, Eric Dumazet wrote:
>>>> diff --git a/net/ipv6/route.c b/net/ipv6/route.c
>>>> index 78362822b9070df138a0724dc76003b63026f9e2..335cdbfe621e2fc4a71badf4ff834870638d5e13 100644
>>>> --- a/net/ipv6/route.c
>>>> +++ b/net/ipv6/route.c
>>>> @@ -1048,7 +1048,7 @@ static const int fib6_prop[RTN_MAX + 1] = {
>>>>       [RTN_BROADCAST] = 0,
>>>>       [RTN_ANYCAST]   = 0,
>>>>       [RTN_MULTICAST] = 0,
>>>> -     [RTN_BLACKHOLE] = -EINVAL,
>>>> +     [RTN_BLACKHOLE] = 0,
>>>>       [RTN_UNREACHABLE] = -EHOSTUNREACH,
>>>>       [RTN_PROHIBIT]  = -EACCES,
>>>>       [RTN_THROW]     = -EAGAIN,
>>>
>>> EINVAL goes back to ef2c7d7b59708 in 2012, so this is a change in user
>>> visible behavior. Also this will make ipv6 deviate from ipv4:
>>>
>>>         [RTN_BLACKHOLE] = {
>>>                 .error  = -EINVAL,
>>>                 .scope  = RT_SCOPE_UNIVERSE,
>>>         },
>>
>> Should we create a new RTN_SINK (or different name), for both IPv4 and IPv6 ?
> 
> Sorry for sidelining, but depending on how this discussion goes,
> tools/testing/selftests/net/fib_nexthops.sh test might need to be
> adjusted (currently fails presumably because of -EINVAL change):
> 
> https://netdev-3.bots.linux.dev/vmksft-net/results/990081/2-fib-nexthops-sh/stdout
> 

yep, I verified that yesterday - there are blackhole selftests. At this
point SINK or whatever the name would have to be a new API, including
how the route is installed if no local failure is really desired.