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

Quoting Eric Paris (eparis(a)redhat.com): > On Tue, 2013-12-10 at 10:51 -0600, Serge Hallyn wrote: >> Quoting Gao feng (gaofeng(a)cn.fujitsu.com): >>> On 12/10/2013 02:26 AM, Serge Hallyn wrote: >>>> Quoting Gao feng (gaofeng(a)cn.fujitsu.com): >>>>> On 12/07/2013 06:12 AM, Serge E. Hallyn wrote: >>>>>> Quoting Gao feng (gaofeng(a)cn.fujitsu.com): >>>>>>> Hi >>>>>>> >>>>>>> On 10/24/2013 03:31 PM, Gao feng wrote: >>>>>>>> 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. >>>>>>>> >>>>>>> >>>>>>> I really need this feature, right now,some process such as >>>>>>> logind are broken in container becase we leak of this feature. >>>>>> >>>>>> Your set doesn't address loginuid though right? How exactly do you >>>>>> expect to do that? If user violates MAC policy and audit msg is >>>>>> sent to init user ns by mac subsys, you need the loginuid from >>>>>> init_audit_ns. where will that be stored if you allow updates >>>>>> of loginuid in auditns? >>>>>> >>>>> This patchset doesn't include the loginuid part. >>>>> >>>>> the loginuid is stored in task as before. >>>>> In my opinion, when task creates a new audit namespace, this task's >>>>> loginuid will be reset to zero, so the children tasks can set their >>>>> loginuid. Does this change break the MAC? >>>> >>>> I think so, yes. In an LSPP selinux environment, if the task >>>> manages to trigger an selinux deny rule which is audited, then >>>> the loginuid must make sense on the host. Now presumably it >>>> will get translated to the mapped host uid, and we can figure >>>> out the host uid owning it through /etc/subuid. But that adds >>>> /etc/subuid as a new part of the TCB without any warning <shrug> >>>> So in that sense, for LSPP, it breaks it. >>>> >>> >>> Looks like my opinion is incorrect. >>> >>> In the audit-next tree, Eric added a new audit feature to allow privileged >>> user to disable AUDIT_LOGINUID_IMMUTABLE. after AUDIT_LOGINUID_IMMUTABLE >>> is disabled, the privileged user can reset/set the loginuid of task. I >>> think this way is safe since only privileged user can do the change. >>> >>> So I will not change the loginuid part. >>> >>> Thanks for your information Serge :) >> >> Unfortunately this makes the patchset much less compelling :) The >> problem I was looking into is that a container running in a user >> namespace cannot (bc he has ns_capable(CAP_AUDIT_*) but not >> capable(CAP_AUDIT_*)) set loginuids at all. >> >> Which from an LSPP pov is correct; which is why I was hoping you were >> going to have the audit namespaces be hierarchical, with a task in a >> level 2 audit ns having two loginuids - one in his own auditns, and >> one in the initial one. > > Right now user namespace + audit is just total crud. We all know > this... (I'm not sure pid is must better, but I digress) All thoughts > around loginuid in the kernel right this very moment only make sense in > the initial user namespace and all permission checks are in the initial > user namespace as well. > > I think I'm a proponent of the hierarchical approach to audit > namespaces. An audit namespace would hold a reference to the > pid/user/whatever namespace it was created in/with. Each audit > namespace should have it's own set of filter rules, etc. Instead of > just storing 'loginuid' we store 'loginuid+user namespace'. When the So long as the kernel stores the kuid_t (which the only sane thing to do) that is a non-issue. > kernel creates a record it should translate the loginuid to the > namespace of the audit namespace and send the record. Yup, that should go without saying. Use kuid_t in kernel and translate at the kernel-user boundary.

> It's a pretty major rewrite, but at least it makes sense. Things like > AVC's might show up in multiple audit logs, but in every log they would > make sense to the admin of that namespace... > > But what the hell do I know... Exactly how it would all affect selinux. I'm happy it seems we agree.