nsproxy.c 5.1 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235
  1. /*
  2. * Copyright (C) 2006 IBM Corporation
  3. *
  4. * Author: Serge Hallyn <serue@us.ibm.com>
  5. *
  6. * This program is free software; you can redistribute it and/or
  7. * modify it under the terms of the GNU General Public License as
  8. * published by the Free Software Foundation, version 2 of the
  9. * License.
  10. *
  11. * Jun 2006 - namespaces support
  12. * OpenVZ, SWsoft Inc.
  13. * Pavel Emelianov <xemul@openvz.org>
  14. */
  15. #include <linux/module.h>
  16. #include <linux/nsproxy.h>
  17. #include <linux/init_task.h>
  18. #include <linux/mnt_namespace.h>
  19. #include <linux/utsname.h>
  20. #include <linux/pid_namespace.h>
  21. #include <net/net_namespace.h>
  22. #include <linux/ipc_namespace.h>
  23. static struct kmem_cache *nsproxy_cachep;
  24. struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy);
  25. /*
  26. * creates a copy of "orig" with refcount 1.
  27. */
  28. static inline struct nsproxy *clone_nsproxy(struct nsproxy *orig)
  29. {
  30. struct nsproxy *ns;
  31. ns = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL);
  32. if (ns) {
  33. memcpy(ns, orig, sizeof(struct nsproxy));
  34. atomic_set(&ns->count, 1);
  35. }
  36. return ns;
  37. }
  38. /*
  39. * Create new nsproxy and all of its the associated namespaces.
  40. * Return the newly created nsproxy. Do not attach this to the task,
  41. * leave it to the caller to do proper locking and attach it to task.
  42. */
  43. static struct nsproxy *create_new_namespaces(unsigned long flags,
  44. struct task_struct *tsk, struct fs_struct *new_fs)
  45. {
  46. struct nsproxy *new_nsp;
  47. int err;
  48. new_nsp = clone_nsproxy(tsk->nsproxy);
  49. if (!new_nsp)
  50. return ERR_PTR(-ENOMEM);
  51. new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, new_fs);
  52. if (IS_ERR(new_nsp->mnt_ns)) {
  53. err = PTR_ERR(new_nsp->mnt_ns);
  54. goto out_ns;
  55. }
  56. new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns);
  57. if (IS_ERR(new_nsp->uts_ns)) {
  58. err = PTR_ERR(new_nsp->uts_ns);
  59. goto out_uts;
  60. }
  61. new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns);
  62. if (IS_ERR(new_nsp->ipc_ns)) {
  63. err = PTR_ERR(new_nsp->ipc_ns);
  64. goto out_ipc;
  65. }
  66. new_nsp->pid_ns = copy_pid_ns(flags, task_active_pid_ns(tsk));
  67. if (IS_ERR(new_nsp->pid_ns)) {
  68. err = PTR_ERR(new_nsp->pid_ns);
  69. goto out_pid;
  70. }
  71. new_nsp->net_ns = copy_net_ns(flags, tsk->nsproxy->net_ns);
  72. if (IS_ERR(new_nsp->net_ns)) {
  73. err = PTR_ERR(new_nsp->net_ns);
  74. goto out_net;
  75. }
  76. return new_nsp;
  77. out_net:
  78. if (new_nsp->pid_ns)
  79. put_pid_ns(new_nsp->pid_ns);
  80. out_pid:
  81. if (new_nsp->ipc_ns)
  82. put_ipc_ns(new_nsp->ipc_ns);
  83. out_ipc:
  84. if (new_nsp->uts_ns)
  85. put_uts_ns(new_nsp->uts_ns);
  86. out_uts:
  87. if (new_nsp->mnt_ns)
  88. put_mnt_ns(new_nsp->mnt_ns);
  89. out_ns:
  90. kmem_cache_free(nsproxy_cachep, new_nsp);
  91. return ERR_PTR(err);
  92. }
  93. /*
  94. * called from clone. This now handles copy for nsproxy and all
  95. * namespaces therein.
  96. */
  97. int copy_namespaces(unsigned long flags, struct task_struct *tsk)
  98. {
  99. struct nsproxy *old_ns = tsk->nsproxy;
  100. struct nsproxy *new_ns;
  101. int err = 0;
  102. if (!old_ns)
  103. return 0;
  104. get_nsproxy(old_ns);
  105. if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
  106. CLONE_NEWPID | CLONE_NEWNET)))
  107. return 0;
  108. if (!capable(CAP_SYS_ADMIN)) {
  109. err = -EPERM;
  110. goto out;
  111. }
  112. /*
  113. * CLONE_NEWIPC must detach from the undolist: after switching
  114. * to a new ipc namespace, the semaphore arrays from the old
  115. * namespace are unreachable. In clone parlance, CLONE_SYSVSEM
  116. * means share undolist with parent, so we must forbid using
  117. * it along with CLONE_NEWIPC.
  118. */
  119. if ((flags & CLONE_NEWIPC) && (flags & CLONE_SYSVSEM)) {
  120. err = -EINVAL;
  121. goto out;
  122. }
  123. new_ns = create_new_namespaces(flags, tsk, tsk->fs);
  124. if (IS_ERR(new_ns)) {
  125. err = PTR_ERR(new_ns);
  126. goto out;
  127. }
  128. tsk->nsproxy = new_ns;
  129. out:
  130. put_nsproxy(old_ns);
  131. return err;
  132. }
  133. void free_nsproxy(struct nsproxy *ns)
  134. {
  135. if (ns->mnt_ns)
  136. put_mnt_ns(ns->mnt_ns);
  137. if (ns->uts_ns)
  138. put_uts_ns(ns->uts_ns);
  139. if (ns->ipc_ns)
  140. put_ipc_ns(ns->ipc_ns);
  141. if (ns->pid_ns)
  142. put_pid_ns(ns->pid_ns);
  143. put_net(ns->net_ns);
  144. kmem_cache_free(nsproxy_cachep, ns);
  145. }
  146. /*
  147. * Called from unshare. Unshare all the namespaces part of nsproxy.
  148. * On success, returns the new nsproxy.
  149. */
  150. int unshare_nsproxy_namespaces(unsigned long unshare_flags,
  151. struct nsproxy **new_nsp, struct fs_struct *new_fs)
  152. {
  153. int err = 0;
  154. if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
  155. CLONE_NEWNET)))
  156. return 0;
  157. if (!capable(CAP_SYS_ADMIN))
  158. return -EPERM;
  159. *new_nsp = create_new_namespaces(unshare_flags, current,
  160. new_fs ? new_fs : current->fs);
  161. if (IS_ERR(*new_nsp)) {
  162. err = PTR_ERR(*new_nsp);
  163. goto out;
  164. }
  165. err = ns_cgroup_clone(current, task_pid(current));
  166. if (err)
  167. put_nsproxy(*new_nsp);
  168. out:
  169. return err;
  170. }
  171. void switch_task_namespaces(struct task_struct *p, struct nsproxy *new)
  172. {
  173. struct nsproxy *ns;
  174. might_sleep();
  175. ns = p->nsproxy;
  176. rcu_assign_pointer(p->nsproxy, new);
  177. if (ns && atomic_dec_and_test(&ns->count)) {
  178. /*
  179. * wait for others to get what they want from this nsproxy.
  180. *
  181. * cannot release this nsproxy via the call_rcu() since
  182. * put_mnt_ns() will want to sleep
  183. */
  184. synchronize_rcu();
  185. free_nsproxy(ns);
  186. }
  187. }
  188. void exit_task_namespaces(struct task_struct *p)
  189. {
  190. switch_task_namespaces(p, NULL);
  191. }
  192. static int __init nsproxy_cache_init(void)
  193. {
  194. nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC);
  195. return 0;
  196. }
  197. module_init(nsproxy_cache_init);