+/*
+ * Clone a new ns copying an original utsname, setting refcount to 1
+ * @old_ns: namespace to clone
+ * Return NULL on error (failure to kmalloc), new ns otherwise
+ */
+static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns)
+{
+ struct uts_namespace *ns;
+
+ ns = kmalloc(sizeof(struct uts_namespace), GFP_KERNEL);
+ if (ns) {
+ memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
+ kref_init(&ns->kref);
+ }
+ return ns;
+}
+
+/*
+ * unshare the current process' utsname namespace.
+ * called only in sys_unshare()
+ */
+int unshare_utsname(unsigned long unshare_flags, struct uts_namespace **new_uts)
+{
+ if (unshare_flags & CLONE_NEWUTS) {
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ *new_uts = clone_uts_ns(current->nsproxy->uts_ns);
+ if (!*new_uts)
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+