lkml.org 
[lkml]   [2014]   [Mar]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH 2/2] net: Implement SO_PEERCGROUP
On Wed, Mar 12, 2014 at 2:00 PM, Andy Lutomirski <luto@amacapital.net> wrote:
> On 03/12/2014 01:46 PM, Vivek Goyal wrote:
>> Implement SO_PEERCGROUP along the lines of SO_PEERCRED. This returns the
>> cgroup of first mounted hierarchy of the task. For the case of client,
>> it represents the cgroup of client at the time of opening the connection.
>> After that client cgroup might change.
>
> Even if people decide that sending cgroups over a unix socket is a good
> idea, this API has my NAK in the strongest possible sense, for whatever
> my NAK is worth.
>
> IMO SO_PEERCRED is a disaster. Calling send(2) or write(2) should
> *never* imply the use of a credential. A program should always have to
> *explicitly* request use of a credential. What you want is SCM_CGROUP.
>
> (I've found privilege escalations before based on this observation, and
> I suspect I'll find them again.)
>
>
> Note that I think that you really want SCM_SOMETHING_ELSE and not
> SCM_CGROUP, but I don't know what the use case is yet.

This might not be quite as awful as I thought. At least you're
looking up the cgroup at connection time instead of at send time.

OTOH, this is still racy -- the socket could easily outlive the cgroup
that created it.

--Andy


\
 
 \ /
  Last update: 2014-03-12 23:01    [W:3.723 / U:0.012 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site