Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Message-ID: <53A40646.5000204@redhat.com>
Date: Fri, 20 Jun 2014 06:00:38 -0400
From: Daniel J Walsh <dwalsh@...hat.com>
To: oss-security@...ts.openwall.com
Subject: Re: docker VMM breakout


On 06/19/2014 01:38 AM, gremlin@...mlin.ru wrote:
> On 18-Jun-2014 10:05:35 -0400, Daniel J Walsh wrote:
>
>  > CONTAINERS DO NOT CONTAIN. Root inside the container == Root
>  > outside the container.
>
> Really? :-)
>
>  > This is true in both libvirt-sandbox/libvirt-lxc and docker.
>
> Have you checked that for anything else?
>
>  > We have a long way to go before we can run anything within a
>  > container without this rule. User Namespace, SELinux or other
>  > MAC are all required to get us near the point where Container
>  > Contain.
>
> Have you ever seen OpenVZ?
I am talking about standard Linux Kernel.  I have not played with OpenVZ
so I can not comment on its security.
>
>  > People who run services within a container should continue to
>  > drop privs in the services and run them as UID!=0
>
> Look at this trivial code example...
>
> Classic kernel:
>
> if (!uid)
> {
> 	// perform privileged operation here
> }
>
> Containers-enabled kernel:
>
> if ( !uid && !container_id )	// container_id: 0 for host
> {
> 	// perform privileged operation here
> }
>
> How would you bypass this check to get privileged access to anything
> outside the container?
>
>
My point being that any process on a Linux System that has lots of linux
capabilities (DAC*, SYS_ADMIN, and many others) can not be contained. 

I think it is premature to treat breakouts against Docker Containers
with CVE's because of this.  If people stop making claims about the
security of a docker process with privs being isolated from the host
system, we can prevent the flood of CVE's, that are likely to come.

Powered by blists - more mailing lists

Please check out the Open Source Software Security Wiki, which is counterpart to this mailing list.

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.