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 <net/net_namespace.h> 24 #include <linux/ipc_namespace.h> 25 26 static struct kmem_cache *nsproxy_cachep; 27 28 struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy); 29 30 /* 31 * creates a copy of "orig" with refcount 1. 32 */ 33 static inline struct nsproxy *clone_nsproxy(struct nsproxy *orig) 34 { 35 struct nsproxy *ns; 36 37 ns = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL); 38 if (ns) { 39 memcpy(ns, orig, sizeof(struct nsproxy)); 40 atomic_set(&ns->count, 1); 41 } 42 return ns; 43 } 44 45 /* 46 * Create new nsproxy and all of its the associated namespaces. 47 * Return the newly created nsproxy. Do not attach this to the task, 48 * leave it to the caller to do proper locking and attach it to task. 49 */ 50 static struct nsproxy *create_new_namespaces(unsigned long flags, 51 struct task_struct *tsk, struct fs_struct *new_fs) 52 { 53 struct nsproxy *new_nsp; 54 int err; 55 56 new_nsp = clone_nsproxy(tsk->nsproxy); 57 if (!new_nsp) 58 return ERR_PTR(-ENOMEM); 59 60 new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, new_fs); 61 if (IS_ERR(new_nsp->mnt_ns)) { 62 err = PTR_ERR(new_nsp->mnt_ns); 63 goto out_ns; 64 } 65 66 new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns); 67 if (IS_ERR(new_nsp->uts_ns)) { 68 err = PTR_ERR(new_nsp->uts_ns); 69 goto out_uts; 70 } 71 72 new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns); 73 if (IS_ERR(new_nsp->ipc_ns)) { 74 err = PTR_ERR(new_nsp->ipc_ns); 75 goto out_ipc; 76 } 77 78 new_nsp->pid_ns = copy_pid_ns(flags, task_active_pid_ns(tsk)); 79 if (IS_ERR(new_nsp->pid_ns)) { 80 err = PTR_ERR(new_nsp->pid_ns); 81 goto out_pid; 82 } 83 84 new_nsp->user_ns = copy_user_ns(flags, tsk->nsproxy->user_ns); 85 if (IS_ERR(new_nsp->user_ns)) { 86 err = PTR_ERR(new_nsp->user_ns); 87 goto out_user; 88 } 89 90 new_nsp->net_ns = copy_net_ns(flags, tsk->nsproxy->net_ns); 91 if (IS_ERR(new_nsp->net_ns)) { 92 err = PTR_ERR(new_nsp->net_ns); 93 goto out_net; 94 } 95 96 return new_nsp; 97 98 out_net: 99 if (new_nsp->user_ns) 100 put_user_ns(new_nsp->user_ns); 101 out_user: 102 if (new_nsp->pid_ns) 103 put_pid_ns(new_nsp->pid_ns); 104 out_pid: 105 if (new_nsp->ipc_ns) 106 put_ipc_ns(new_nsp->ipc_ns); 107 out_ipc: 108 if (new_nsp->uts_ns) 109 put_uts_ns(new_nsp->uts_ns); 110 out_uts: 111 if (new_nsp->mnt_ns) 112 put_mnt_ns(new_nsp->mnt_ns); 113 out_ns: 114 kmem_cache_free(nsproxy_cachep, new_nsp); 115 return ERR_PTR(err); 116 } 117 118 /* 119 * called from clone. This now handles copy for nsproxy and all 120 * namespaces therein. 121 */ 122 int copy_namespaces(unsigned long flags, struct task_struct *tsk) 123 { 124 struct nsproxy *old_ns = tsk->nsproxy; 125 struct nsproxy *new_ns; 126 int err = 0; 127 128 if (!old_ns) 129 return 0; 130 131 get_nsproxy(old_ns); 132 133 if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | 134 CLONE_NEWUSER | CLONE_NEWPID | CLONE_NEWNET))) 135 return 0; 136 137 if (!capable(CAP_SYS_ADMIN)) { 138 err = -EPERM; 139 goto out; 140 } 141 142 /* 143 * CLONE_NEWIPC must detach from the undolist: after switching 144 * to a new ipc namespace, the semaphore arrays from the old 145 * namespace are unreachable. In clone parlance, CLONE_SYSVSEM 146 * means share undolist with parent, so we must forbid using 147 * it along with CLONE_NEWIPC. 148 */ 149 if ((flags & CLONE_NEWIPC) && (flags & CLONE_SYSVSEM)) { 150 err = -EINVAL; 151 goto out; 152 } 153 154 new_ns = create_new_namespaces(flags, tsk, tsk->fs); 155 if (IS_ERR(new_ns)) { 156 err = PTR_ERR(new_ns); 157 goto out; 158 } 159 160 err = ns_cgroup_clone(tsk); 161 if (err) { 162 put_nsproxy(new_ns); 163 goto out; 164 } 165 166 tsk->nsproxy = new_ns; 167 168 out: 169 put_nsproxy(old_ns); 170 return err; 171 } 172 173 void free_nsproxy(struct nsproxy *ns) 174 { 175 if (ns->mnt_ns) 176 put_mnt_ns(ns->mnt_ns); 177 if (ns->uts_ns) 178 put_uts_ns(ns->uts_ns); 179 if (ns->ipc_ns) 180 put_ipc_ns(ns->ipc_ns); 181 if (ns->pid_ns) 182 put_pid_ns(ns->pid_ns); 183 if (ns->user_ns) 184 put_user_ns(ns->user_ns); 185 put_net(ns->net_ns); 186 kmem_cache_free(nsproxy_cachep, ns); 187 } 188 189 /* 190 * Called from unshare. Unshare all the namespaces part of nsproxy. 191 * On success, returns the new nsproxy. 192 */ 193 int unshare_nsproxy_namespaces(unsigned long unshare_flags, 194 struct nsproxy **new_nsp, struct fs_struct *new_fs) 195 { 196 int err = 0; 197 198 if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | 199 CLONE_NEWUSER | CLONE_NEWNET))) 200 return 0; 201 202 if (!capable(CAP_SYS_ADMIN)) 203 return -EPERM; 204 205 *new_nsp = create_new_namespaces(unshare_flags, current, 206 new_fs ? new_fs : current->fs); 207 if (IS_ERR(*new_nsp)) { 208 err = PTR_ERR(*new_nsp); 209 goto out; 210 } 211 212 err = ns_cgroup_clone(current); 213 if (err) 214 put_nsproxy(*new_nsp); 215 216 out: 217 return err; 218 } 219 220 void switch_task_namespaces(struct task_struct *p, struct nsproxy *new) 221 { 222 struct nsproxy *ns; 223 224 might_sleep(); 225 226 ns = p->nsproxy; 227 228 rcu_assign_pointer(p->nsproxy, new); 229 230 if (ns && atomic_dec_and_test(&ns->count)) { 231 /* 232 * wait for others to get what they want from this nsproxy. 233 * 234 * cannot release this nsproxy via the call_rcu() since 235 * put_mnt_ns() will want to sleep 236 */ 237 synchronize_rcu(); 238 free_nsproxy(ns); 239 } 240 } 241 242 void exit_task_namespaces(struct task_struct *p) 243 { 244 switch_task_namespaces(p, NULL); 245 } 246 247 static int __init nsproxy_cache_init(void) 248 { 249 nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC); 250 return 0; 251 } 252 253 module_init(nsproxy_cache_init); 254