netdev - Re: [PATCH v2 net-next 03/11] net/ipv4: Plumb support for filtering route dumps

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]

Message-ID: <147df36b-75df-5e71-3d74-9454db676bce@gmail.com>
Date:   Fri, 19 Jul 2019 10:55:49 -0600
From:   David Ahern <dsahern@...il.com>
To:     Hangbin Liu <liuhangbin@...il.com>,
        David Ahern <dsahern@...nel.org>
Cc:     netdev@...r.kernel.org, Jianlin Shi <jishi@...hat.com>
Subject: Re: [PATCH v2 net-next 03/11] net/ipv4: Plumb support for filtering
 route dumps

Hi:

On 7/18/19 10:17 PM, Hangbin Liu wrote:
> Hi David,
> 
> Before commit 18a8021a7be3 ("net/ipv4: Plumb support for filtering route
> dumps"), when we dump a non-exist table, ip cmd exits silently.
> 
> # ip -4 route list table 1
> # echo $?
> 0
> 
> After commit 18a8021a7be3 ("net/ipv4: Plumb support for filtering route
> dumps"). When we dump a non-exist table, as we returned -ENOENT, ip route
> shows:
> 
> # ip -4 route show table 1
> Error: ipv4: FIB table does not exist.
> Dump terminated
> # echo $?
> 2
> 
> For me it looks make sense to return -ENOENT if we do not have the route
> table. But this changes the userspace behavior. Do you think if we need to
> keep backward compatible or just let it do as it is right now?
> 

It is not change in userspace behavior; ip opted into the strict
checking. The impact is to 'ip' users.

A couple of people have asked about this, and I am curious as to why
people run a route dump for a table that does not exist and do not like
being told that it does not exist.