Re: [RFC Part1 PATCH 00/20 v2] Add namespace support for audit

Gao feng
2013-12-09T02:29:15Z

Hi Serge,

Thanks for your comments!

On 12/07/2013 05:31 AM, Serge E. Hallyn wrote:
> Quoting Gao feng (gaofeng-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org):
>> Here is the v1 patchset: http://lwn.net/Articles/549546/
>>
>> The main target of this patchset is allowing user in audit
>> namespace to generate the USER_MSG type of audit message,
>> some userspace tools need to generate audit message, or
>> these tools will broken.
>>
>> And the login process in container may want to setup
>> /proc/<pid>/loginuid, right now this value is unalterable
>> once it being set. this will also broke the login problem
>> in container. After this patchset, we can reset this loginuid
>> to zero if task is running in a new audit namespace.
>>
>> Same with v1 patchset, in this patchset, only the privileged
>> user in init_audit_ns and init_user_ns has rights to
>> add/del audit rules. and these rules are gloabl. all
>> audit namespace will comply with the rules.
>>
>> Compared with v1, v2 patch has some big changes.
>> 1, the audit namespace is not assigned to user namespace.
>> since there is no available bit of flags for clone, we
>> create audit namespace through netlink, patch[18/20]
>> introduces a new audit netlink type AUDIT_CREATE_NS.
>> the privileged user in userns has rights to create a
>> audit namespace, it means the unprivileged user can
>> create auditns through create userns first. In order
>> to prevent them from doing harm to host, the default
>> audit_backlog_limit of un-init-audit-ns is zero(means
>> audit is unavailable in audit namespace). and it can't
>> be changed in auditns through netlink.
>
> So the unprivileged user can create an audit-ns, but can't
> then actually send any messages there? I guess setting it
> to something small would just be hacky?

Yes, if unprivileged user wants to send audit message, he should
ask privileged user to setup the audit_backlog_limit for him.

I know it's a little of hack, but I don't have good idea :(