netdev - Re: [PATCH net] ipv6: no need to return rt->dst.error if it is not null entry.

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]

Date:   Thu, 27 Jul 2017 21:56:08 -0700
From:   Cong Wang <xiyou.wangcong@...il.com>
To:     David Ahern <dsahern@...il.com>
Cc:     Roopa Prabhu <roopa@...ulusnetworks.com>,
        Hangbin Liu <liuhangbin@...il.com>,
        network dev <netdev@...r.kernel.org>
Subject: Re: [PATCH net] ipv6: no need to return rt->dst.error if it is not
 null entry.

On Wed, Jul 26, 2017 at 11:49 AM, David Ahern <dsahern@...il.com> wrote:
> On 7/26/17 12:27 PM, Roopa Prabhu wrote:
>> agreed...so looks like the check in v3 should be
>>
>>
>> +       if ( rt == net->ipv6.ip6_null_entry ||
>> +            (rt->dst.error &&
>> + #ifdef CONFIG_IPV6_MULTIPLE_TABLES
>> +              rt != net->ipv6.ip6_prohibit_entry &&
>> +              rt != net->ipv6.ip6_blk_hole_entry &&
>> +#endif
>> +             )) {
>>                 err = rt->dst.error;
>>                 ip6_rt_put(rt);
>>                 goto errout;
>>
>
> I don't think so. If I add a prohibit route and use the fibmatch
> attribute, I want to see the route from the FIB that was matched.

But net->ipv6.ip6_prohibit_entry is not the prohibit route you can
add in user-space, it is only used by rule actions. So do you really
want to dump it?? My gut feeling is no, but I am definitely not sure.

When you add a prohibit route, a new rt is allocated dynamically,
net->ipv6.ip6_prohibit_entry is relatively static, internal and is the
only one per netns. (Same for net->ipv6.ip6_blk_hole_entry)

I think Hangbin's example doesn't have ip rules, so this case
is not shown up.