On 2018-04-18 15:39, Stefan Berger wrote: > On 04/18/2018 03:23 PM, Richard Guy Briggs wrote: > > On 2018-04-18 14:45, Stefan Berger wrote: > > > On 03/15/2018 11:58 PM, Richard Guy Briggs wrote: > > > > On 2018-03-15 16:27, Stefan Berger wrote: > > > > > On 03/01/2018 02:41 PM, Richard Guy Briggs wrote: > > > > > > Implement the proc fs write to set the audit container ID of a process, > > > > > > emitting an AUDIT_CONTAINER record to document the event. > > > > > > > > > > > > This is a write from the container orchestrator task to a proc entry of > > > > > > the form /proc/PID/containerid where PID is the process ID of the newly > > > > > > created task that is to become the first task in a container, or an > > > > > > additional task added to a container. > > > > > > > > > > > > The write expects up to a u64 value (unset: 18446744073709551615). > > > > > > > > > > > > This will produce a record such as this: > > > > > > type=UNKNOWN[1333] msg=audit(1519903238.968:261): op=set pid=596 uid=0 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 auid=0 tty=pts0 ses=1 opid=596 old-contid=18446744073709551615 contid=123455 res=0 > > > > > > > > > > > > The "op" field indicates an initial set. The "pid" to "ses" fields are > > > > > > the orchestrator while the "opid" field is the object's PID, the process > > > > > > being "contained". Old and new container ID values are given in the > > > > > > "contid" fields, while res indicates its success. > > > > > > > > > > > > It is not permitted to self-set, unset or re-set the container ID. A > > > > > > child inherits its parent's container ID, but then can be set only once > > > > > > after. > > > > > > > > > > > > See: https://github.com/linux-audit/audit-kernel/issues/32 > > > > > > > > > > > > > > > > > > /* audit_rule_data supports filter rules with both integer and string > > > > > > * fields. It corresponds with AUDIT_ADD_RULE, AUDIT_DEL_RULE and > > > > > > diff --git a/kernel/auditsc.c b/kernel/auditsc.c > > > > > > index 4e0a4ac..0ee1e59 100644 > > > > > > --- a/kernel/auditsc.c > > > > > > +++ b/kernel/auditsc.c > > > > > > @@ -2073,6 +2073,92 @@ int audit_set_loginuid(kuid_t loginuid) > > > > > > return rc; > > > > > > } > > > > > > > > > > > > +static int audit_set_containerid_perm(struct task_struct *task, u64 containerid) > > > > > > +{ > > > > > > + struct task_struct *parent; > > > > > > + u64 pcontainerid, ccontainerid; > > > > > > + pid_t ppid; > > > > > > + > > > > > > + /* Don't allow to set our own containerid */ > > > > > > + if (current == task) > > > > > > + return -EPERM; > > > > > > + /* Don't allow the containerid to be unset */ > > > > > > + if (!cid_valid(containerid)) > > > > > > + return -EINVAL; > > > > > > + /* if we don't have caps, reject */ > > > > > > + if (!capable(CAP_AUDIT_CONTROL)) > > > > > > + return -EPERM; > > > > > > + /* if containerid is unset, allow */ > > > > > > + if (!audit_containerid_set(task)) > > > > > > + return 0; > > > > > I am wondering whether there should be a check for the target process that > > > > > will receive the containerid to not have CAP_SYS_ADMIN that would otherwise > > > > > allow it to arbitrarily unshare()/clone() and leave the set of namespaces > > > > > that may make up the container whose containerid we assign here? > > > > This is a reasonable question. This has been debated and I understood > > > > the conclusion was that without a clear definition of a "container", the > > > > task still remains in that container that just now has more > > > > sub-namespaces (in the case of hierarchical namespaces), we don't want > > > > to restrict it in such a way and that allows it to create nested > > > > containers. I see setns being more problematic if it could switch to > > > > another existing namespace that was set up by the orchestrator for a > > > > different container. The coming v2 patchset acknowledges this situation > > > > with the network namespace being potentially shared by multiple > > > > containers. > > > Are you going to post v2 soon? We would like to build on top of it for IMA > > > namespacing and auditing inside of IMA namespaces. > > I don't know if it addresses your specific needs, but V2 was posted on > > March 16th along with userspace patches: > > https://www.redhat.com/archives/linux-audit/2018-March/msg00110.html > > https://www.redhat.com/archives/linux-audit/2018-March/msg00124.html > > > > V3 is pending. > Thanks. I hadn't actually looked at primarily due to the ghak and ghau in > the title. Whatever these may mean. They are Github issue numbers: GHAK: GitHub Audit Kernel GHAU: GitHub Audit Userspace GHAD: GitHub Audit Documentation GHAT: GitHub Audit Testsuite > Does V2 or will V3 prevent a privileged process to setns() to a whole > different set of namespaces and still be audited with that initial container > id ? No, not significantly different from V1 in that respect. It does not prevent setns(), but will maintain its containerid. It will prevent games by blocking a child and parent from setting each other's containerids. It does check that the task being conainered does not yet have any children or peer threads. - RGB -- Richard Guy Briggs <rgb@xxxxxxxxxx> Sr. S/W Engineer, Kernel Security, Base Operating Systems Remote, Ottawa, Red Hat Canada IRC: rgb, SunRaycer Voice: +1.647.777.2635, Internal: (81) 32635
