Re: [PATCH ghak90 V6 02/10] audit: add container id

It is not permitted to unset the audit container identifier. A child inherits its parent's audit container identifier.

/** + * audit_set_contid - set current task's audit 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); + /* 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;