Re: [PATCH 2/9] security: Make capabilities relative to the usernamespace.

From: Daniel Lezcano
Date: Fri Feb 18 2011 - 18:45:09 EST


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@xxxxxxxxxxxx>
Signed-off-by: Serge E. Hallyn<serge.hallyn@xxxxxxxxxxxxx>
---

Acked-by: Daniel Lezcano <daniel.lezcano@xxxxxxx>

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