Messages in this thread | | | Subject | Re: [RFC PATCH V1 01/12] audit: add container id | From | Stefan Berger <> | Date | Wed, 18 Apr 2018 14:45:14 -0400 |
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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.
Stefan
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