+int subsys_cgroup_allow_attach(struct cgroup_taskset *tset)
+{
+ const struct cred *cred = current_cred(), *tcred;
+ struct task_struct *task;
+ struct cgroup_subsys_state *css;
+
+ if (capable(CAP_SYS_NICE))
+ return 0;
+
+ cgroup_taskset_for_each(task, css, tset) {
+ tcred = __task_cred(task);
+
+ if (current != task && !uid_eq(cred->euid, tcred->uid) &&
+ !uid_eq(cred->euid, tcred->suid))
+ return -EACCES;
+ }
+
+ return 0;
+}
+
+static int cgroup_allow_attach(struct cgroup *cgrp, struct cgroup_taskset *tset)
+{
+ struct cgroup_subsys_state *css;
+ int i;
+ int ret;
+
+ for_each_css(css, i, cgrp) {
+ if (css->ss->allow_attach) {
+ ret = css->ss->allow_attach(tset);
+ if (ret)
+ return ret;
+ } else {
+ return -EACCES;
+ }
+ }
+
+ return 0;
+}
+