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 16#include <linux/module.h> 17#include <linux/version.h> 18#include <linux/nsproxy.h> 19#include <linux/init_task.h> 20#include <linux/mnt_namespace.h> 21#include <linux/utsname.h> 22#include <linux/pid_namespace.h> 23#include <linux/user_namespace.h> 24 25static struct kmem_cache *nsproxy_cachep; 26 27struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy); 28 29static inline void get_nsproxy(struct nsproxy *ns) 30{ 31 atomic_inc(&ns->count); 32} 33 34void get_task_namespaces(struct task_struct *tsk) 35{ 36 struct nsproxy *ns = tsk->nsproxy; 37 if (ns) { 38 get_nsproxy(ns); 39 } 40} 41 42/* 43 * creates a copy of "orig" with refcount 1. 44 */ 45static inline struct nsproxy *clone_nsproxy(struct nsproxy *orig) 46{ 47 struct nsproxy *ns; 48 49 ns = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL); 50 if (ns) { 51 memcpy(ns, orig, sizeof(struct nsproxy)); 52 atomic_set(&ns->count, 1); 53 } 54 return ns; 55} 56 57/* 58 * Create new nsproxy and all of its the associated namespaces. 59 * Return the newly created nsproxy. Do not attach this to the task, 60 * leave it to the caller to do proper locking and attach it to task. 61 */ 62static struct nsproxy *create_new_namespaces(unsigned long flags, 63 struct task_struct *tsk, struct fs_struct *new_fs) 64{ 65 struct nsproxy *new_nsp; 66 int err; 67 68 new_nsp = clone_nsproxy(tsk->nsproxy); 69 if (!new_nsp) 70 return ERR_PTR(-ENOMEM); 71 72 new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, new_fs); 73 if (IS_ERR(new_nsp->mnt_ns)) { 74 err = PTR_ERR(new_nsp->mnt_ns); 75 goto out_ns; 76 } 77 78 new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns); 79 if (IS_ERR(new_nsp->uts_ns)) { 80 err = PTR_ERR(new_nsp->uts_ns); 81 goto out_uts; 82 } 83 84 new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns); 85 if (IS_ERR(new_nsp->ipc_ns)) { 86 err = PTR_ERR(new_nsp->ipc_ns); 87 goto out_ipc; 88 } 89 90 new_nsp->pid_ns = copy_pid_ns(flags, tsk->nsproxy->pid_ns); 91 if (IS_ERR(new_nsp->pid_ns)) { 92 err = PTR_ERR(new_nsp->pid_ns); 93 goto out_pid; 94 } 95 96 new_nsp->user_ns = copy_user_ns(flags, tsk->nsproxy->user_ns); 97 if (IS_ERR(new_nsp->user_ns)) { 98 err = PTR_ERR(new_nsp->user_ns); 99 goto out_user; 100 } 101 102 return new_nsp; 103 104out_user: 105 if (new_nsp->pid_ns) 106 put_pid_ns(new_nsp->pid_ns); 107out_pid: 108 if (new_nsp->ipc_ns) 109 put_ipc_ns(new_nsp->ipc_ns); 110out_ipc: 111 if (new_nsp->uts_ns) 112 put_uts_ns(new_nsp->uts_ns); 113out_uts: 114 if (new_nsp->mnt_ns) 115 put_mnt_ns(new_nsp->mnt_ns); 116out_ns: 117 kmem_cache_free(nsproxy_cachep, new_nsp); 118 return ERR_PTR(err); 119} 120 121/* 122 * called from clone. This now handles copy for nsproxy and all 123 * namespaces therein. 124 */ 125int copy_namespaces(unsigned long flags, struct task_struct *tsk) 126{ 127 struct nsproxy *old_ns = tsk->nsproxy; 128 struct nsproxy *new_ns; 129 int err = 0; 130 131 if (!old_ns) 132 return 0; 133 134 get_nsproxy(old_ns); 135 136 if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | CLONE_NEWUSER))) 137 return 0; 138 139 if (!capable(CAP_SYS_ADMIN)) { 140 err = -EPERM; 141 goto out; 142 } 143 144 new_ns = create_new_namespaces(flags, tsk, tsk->fs); 145 if (IS_ERR(new_ns)) { 146 err = PTR_ERR(new_ns); 147 goto out; 148 } 149 150 tsk->nsproxy = new_ns; 151out: 152 put_nsproxy(old_ns); 153 return err; 154} 155 156void free_nsproxy(struct nsproxy *ns) 157{ 158 if (ns->mnt_ns) 159 put_mnt_ns(ns->mnt_ns); 160 if (ns->uts_ns) 161 put_uts_ns(ns->uts_ns); 162 if (ns->ipc_ns) 163 put_ipc_ns(ns->ipc_ns); 164 if (ns->pid_ns) 165 put_pid_ns(ns->pid_ns); 166 if (ns->user_ns) 167 put_user_ns(ns->user_ns); 168 kmem_cache_free(nsproxy_cachep, ns); 169} 170 171/* 172 * Called from unshare. Unshare all the namespaces part of nsproxy. 173 * On success, returns the new nsproxy. 174 */ 175int unshare_nsproxy_namespaces(unsigned long unshare_flags, 176 struct nsproxy **new_nsp, struct fs_struct *new_fs) 177{ 178 int err = 0; 179 180 if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | 181 CLONE_NEWUSER))) 182 return 0; 183 184 if (!capable(CAP_SYS_ADMIN)) 185 return -EPERM; 186 187 *new_nsp = create_new_namespaces(unshare_flags, current, 188 new_fs ? new_fs : current->fs); 189 if (IS_ERR(*new_nsp)) 190 err = PTR_ERR(*new_nsp); 191 return err; 192} 193 194static int __init nsproxy_cache_init(void) 195{ 196 nsproxy_cachep = kmem_cache_create("nsproxy", sizeof(struct nsproxy), 197 0, SLAB_PANIC, NULL, NULL); 198 return 0; 199} 200 201module_init(nsproxy_cache_init); 202