[PATCH 2/9] security: Make capabilities relative to the user namespace.

Daniel Lezcano daniel.lezcano at free.fr
Fri Feb 18 15:44:50 PST 2011

On 02/17/2011 04:03 PM, Serge E. Hallyn wrote:
> - Introduce ns_capable to test for a capability in a non-default
>    user namespace.
> - Teach cap_capable to handle capabilities in a non-default
>    user namespace.
> The motivation is to get to the unprivileged creation of new
> namespaces.  It looks like this gets us 90% of the way there, with
> only potential uid confusion issues left.
> I still need to handle getting all caps after creation but otherwise I
> think I have a good starter patch that achieves all of your goals.
> Changelog:
> 	11/05/2010: [serge] add apparmor
> 	12/14/2010: [serge] fix capabilities to created user namespaces
> 	Without this, if user serge creates a user_ns, he won't have
> 	capabilities to the user_ns he created.  THis is because we
> 	were first checking whether his effective caps had the caps
> 	he needed and returning -EPERM if not, and THEN checking whether
> 	he was the creator.  Reverse those checks.
> 	12/16/2010: [serge] security_real_capable needs ns argument in !security case
> 	01/11/2011: [serge] add task_ns_capable helper
> 	01/11/2011: [serge] add nsown_capable() helper per Bastian Blank suggestion
> 	02/16/2011: [serge] fix a logic bug: the root user is always creator of
> 		    init_user_ns, but should not always have capabilities to
> 		    it!  Fix the check in cap_capable().
> Signed-off-by: Eric W. Biederman<ebiederm at xmission.com>
> Signed-off-by: Serge E. Hallyn<serge.hallyn at canonical.com>
> ---

Acked-by: Daniel Lezcano <daniel.lezcano at free.fr>

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