/* * Copyright (C) 2004 IBM Corporation * * Author: Serge Hallyn <serue@us.ibm.com> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License as * published by the Free Software Foundation, version 2 of the * License. */ #include <linux/module.h> #include <linux/uts.h> #include <linux/utsname.h> #include <linux/version.h> /* * 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; } /* * Copy task tsk's utsname namespace, or clone it if flags * specifies CLONE_NEWUTS. In latter case, changes to the * utsname of this process won't be seen by parent, and vice * versa. */ int copy_utsname(int flags, struct task_struct *tsk) { struct uts_namespace *old_ns = tsk->nsproxy->uts_ns; struct uts_namespace *new_ns; int err = 0; if (!old_ns) return 0; get_uts_ns(old_ns); if (!(flags & CLONE_NEWUTS)) return 0; if (!capable(CAP_SYS_ADMIN)) { err = -EPERM; goto out; } new_ns = clone_uts_ns(old_ns); if (!new_ns) { err = -ENOMEM; goto out; } tsk->nsproxy->uts_ns = new_ns; out: put_uts_ns(old_ns); return err; } void free_uts_ns(struct kref *kref) { struct uts_namespace *ns; ns = container_of(kref, struct uts_namespace, kref); kfree(ns); }