On Tue, Jul 31, 2018 at 4:11 PM Richard Guy Briggs <rgb@xxxxxxxxxx> wrote: > > Implement the proc fs write to set the audit container identifier of a > process, emitting an AUDIT_CONTAINER_OP record to document the event. > > This is a write from the container orchestrator task to a proc entry of > the form /proc/PID/audit_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). > > The writer must have capability CAP_AUDIT_CONTROL. > > This will produce a record such as this: > type=CONTAINER_ID msg=audit(2018-06-06 12:39:29.636:26949) : op=set opid=2209 old-contid=18446744073709551615 contid=123456 pid=628 auid=root uid=root tty=ttyS0 ses=1 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 comm=bash exe=/usr/bin/bash res=yes You need to update the record type in the example above. > 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 audit container identifier values are > given in the "contid" fields, while res indicates its success. I understand Steve's concern around the "op" field, but I think it might be a bit premature to think we might not need to do some sort of audit container ID management in the future that would want to make use of the CONTAINER_OP message type. I would like to see the "op" field preserved. > It is not permitted to unset the audit container identifier. > A child inherits its parent's audit container identifier. > > See: https://github.com/linux-audit/audit-kernel/issues/90 > See: https://github.com/linux-audit/audit-userspace/issues/51 > See: https://github.com/linux-audit/audit-testsuite/issues/64 > See: https://github.com/linux-audit/audit-kernel/wiki/RFE-Audit-Container-ID > > Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx> > Acked-by: Serge Hallyn <serge@xxxxxxxxxx> > Acked-by: Steve Grubb <sgrubb@xxxxxxxxxx> > --- > fs/proc/base.c | 37 +++++++++++++++++++++++++ > include/linux/audit.h | 24 ++++++++++++++++ > include/uapi/linux/audit.h | 2 ++ > kernel/auditsc.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++ > 4 files changed, 131 insertions(+) ... > @@ -2112,6 +2114,72 @@ int audit_set_loginuid(kuid_t loginuid) > } > > /** > + * audit_set_contid - set current task's audit_context contid > + * @contid: contid value > + * > + * Returns 0 on success, -EPERM on permission failure. > + * > + * Called (set) from fs/proc/base.c::proc_contid_write(). > + */ > +int audit_set_contid(struct task_struct *task, u64 contid) > +{ > + u64 oldcontid; > + int rc = 0; > + struct audit_buffer *ab; > + uid_t uid; > + struct tty_struct *tty; > + char comm[sizeof(current->comm)]; > + > + task_lock(task); > + /* Can't set if audit disabled */ > + if (!task->audit) { > + task_unlock(task); > + return -ENOPROTOOPT; > + } > + oldcontid = audit_get_contid(task); > + read_lock(&tasklist_lock); I assume lockdep was happy with nesting the tasklist_lock inside the task lock? > + /* Don't allow the audit containerid to be unset */ > + if (!audit_contid_valid(contid)) > + rc = -EINVAL; > + /* if we don't have caps, reject */ > + else if (!capable(CAP_AUDIT_CONTROL)) > + rc = -EPERM; > + /* if task has children or is not single-threaded, deny */ > + else if (!list_empty(&task->children)) > + rc = -EBUSY; > + else if (!(thread_group_leader(task) && thread_group_empty(task))) > + rc = -EALREADY; > + read_unlock(&tasklist_lock); > + if (!rc) > + task->audit->contid = contid; > + task_unlock(task); > + > + if (!audit_enabled) > + return rc; > + > + ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONTAINER_OP); > + if (!ab) > + return rc; > + > + uid = from_kuid(&init_user_ns, task_uid(current)); > + tty = audit_get_tty(current); > + audit_log_format(ab, "op=set opid=%d old-contid=%llu contid=%llu pid=%d uid=%u auid=%u tty=%s ses=%u", > + task_tgid_nr(task), oldcontid, contid, > + task_tgid_nr(current), uid, > + from_kuid(&init_user_ns, audit_get_loginuid(current)), > + tty ? tty_name(tty) : "(none)", > + audit_get_sessionid(current)); > + audit_put_tty(tty); > + audit_log_task_context(ab); > + audit_log_format(ab, " comm="); > + audit_log_untrustedstring(ab, get_task_comm(comm, current)); > + audit_log_d_path_exe(ab, current->mm); > + audit_log_format(ab, " res=%d", !rc); > + audit_log_end(ab); > + return rc; > +} -- paul moore www.paul-moore.com
