netdev - Re: [PATCH] netns: avoid directory traversal (was: ip netns: Make sure netns name is sane)

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Message-ID: <20170718171230.084c804e@xeon-e3>
Date:   Tue, 18 Jul 2017 17:12:30 -0700
From:   Stephen Hemminger <stephen@...workplumber.org>
To:     Matteo Croce <mcroce@...hat.com>
Cc:     netdev@...r.kernel.org, Phil Sutter <phil@....cc>
Subject: Re: [PATCH] netns: avoid directory traversal (was: ip netns: Make
 sure netns name is sane)

On Mon, 10 Jul 2017 14:08:31 +0200
Matteo Croce <mcroce@...hat.com> wrote:

> Hi Phil,
> 
> I noticed that your patch still leaves an uncovered scenario, the one where the
> namespace name is "." or "..".
> Calling 'ip netns del ..' will remove /var/run which is a symlink to /run on
> most systems causing some daemons, eg. dbus, to fail.
> 
> ip netns doesn't validate input, allowing creation and deletion of files
> relatives to /var/run/netns.
> This patch denies creation or deletion of namespaces with names contaning
> "/" or that matches exactly "." or "..".
> ---
>  ip/ipnetns.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 

The patch itself is good, but the commit message needs fixing.
Please rewrite it to describe the problem, and add signed-off-by