netdev - Re: [PATCH net] net: check and errout if res->fi is NULL when RTM_F_FIB

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: <CAJieiUiDzph45Uzxfp=7rGKarZXpPQ4T488ykBQoZC3VPKSJvg@mail.gmail.com>
Date:   Tue, 15 Aug 2017 21:55:32 -0700
From:   Roopa Prabhu <roopa@...ulusnetworks.com>
To:     David Ahern <dsa@...ulusnetworks.com>
Cc:     "davem@...emloft.net" <davem@...emloft.net>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        Florian Westphal <fw@...len.de>, idaifish <idaifish@...il.com>,
        syzkaller@...glegroups.com, Dmitry Vyukov <dvyukov@...gle.com>,
        Eric Dumazet <eric.dumazet@...il.com>
Subject: Re: [PATCH net] net: check and errout if res->fi is NULL when
 RTM_F_FIB_MATCH is set

On Tue, Aug 15, 2017 at 7:56 PM, David Ahern <dsa@...ulusnetworks.com> wrote:
> On 8/15/17 8:50 PM, Roopa Prabhu wrote:
>> diff --git a/net/ipv4/route.c b/net/ipv4/route.c
>> index 7effa62..49a018f 100644
>> --- a/net/ipv4/route.c
>> +++ b/net/ipv4/route.c
>> @@ -2763,14 +2763,21 @@ static int inet_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh,
>>       if (rtm->rtm_flags & RTM_F_LOOKUP_TABLE)
>>               table_id = rt->rt_table_id;
>>
>> -     if (rtm->rtm_flags & RTM_F_FIB_MATCH)
>> +     if (rtm->rtm_flags & RTM_F_FIB_MATCH) {
>> +             if (!res.fi) {
>> +                     err = fib_props[res->type].error;
>> +                     if (!err)
>> +                             err = -EINVAL;
>
> I think -EHOSTUNREACH is a better error than EINVAL. Nothing about the
> user inputs are invalid; rather the lookup is failing, but indirectly.

 I have been going back and forth on this looking at other examples.
I would have preferred ip_route_input_rcu returned the right error
code for this....but i prefer not to touch that given it may break
something else.

EHOSTUNREACH is only returned for RTN_UNREACHABLE routes.

        [RTN_UNREACHABLE] = {

                .error  = -EHOSTUNREACH,

                .scope  = RT_SCOPE_UNIVERSE,

        },

In the example i am using it was failing due to a daddr being zero. so
seemed like -EINVAL would fit.

If EHOSTUNREACH can cover most errors, I am fine with changing it to
-EHOSTUNREACH.