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/slab.h> 17 #include <linux/export.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 #include <linux/proc_ns.h> 26 #include <linux/file.h> 27 #include <linux/syscalls.h> 28 29 static struct kmem_cache *nsproxy_cachep; 30 31 struct nsproxy init_nsproxy = { 32 .count = ATOMIC_INIT(1), 33 .uts_ns = &init_uts_ns, 34 #if defined(CONFIG_POSIX_MQUEUE) || defined(CONFIG_SYSVIPC) 35 .ipc_ns = &init_ipc_ns, 36 #endif 37 .mnt_ns = NULL, 38 .pid_ns = &init_pid_ns, 39 #ifdef CONFIG_NET 40 .net_ns = &init_net, 41 #endif 42 }; 43 44 static inline struct nsproxy *create_nsproxy(void) 45 { 46 struct nsproxy *nsproxy; 47 48 nsproxy = kmem_cache_alloc(nsproxy_cachep, GFP_KERNEL); 49 if (nsproxy) 50 atomic_set(&nsproxy->count, 1); 51 return nsproxy; 52 } 53 54 /* 55 * Create new nsproxy and all of its the associated namespaces. 56 * Return the newly created nsproxy. Do not attach this to the task, 57 * leave it to the caller to do proper locking and attach it to task. 58 */ 59 static struct nsproxy *create_new_namespaces(unsigned long flags, 60 struct task_struct *tsk, struct user_namespace *user_ns, 61 struct fs_struct *new_fs) 62 { 63 struct nsproxy *new_nsp; 64 int err; 65 66 new_nsp = create_nsproxy(); 67 if (!new_nsp) 68 return ERR_PTR(-ENOMEM); 69 70 new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, user_ns, new_fs); 71 if (IS_ERR(new_nsp->mnt_ns)) { 72 err = PTR_ERR(new_nsp->mnt_ns); 73 goto out_ns; 74 } 75 76 new_nsp->uts_ns = copy_utsname(flags, user_ns, tsk->nsproxy->uts_ns); 77 if (IS_ERR(new_nsp->uts_ns)) { 78 err = PTR_ERR(new_nsp->uts_ns); 79 goto out_uts; 80 } 81 82 new_nsp->ipc_ns = copy_ipcs(flags, user_ns, tsk->nsproxy->ipc_ns); 83 if (IS_ERR(new_nsp->ipc_ns)) { 84 err = PTR_ERR(new_nsp->ipc_ns); 85 goto out_ipc; 86 } 87 88 new_nsp->pid_ns = copy_pid_ns(flags, user_ns, tsk->nsproxy->pid_ns); 89 if (IS_ERR(new_nsp->pid_ns)) { 90 err = PTR_ERR(new_nsp->pid_ns); 91 goto out_pid; 92 } 93 94 new_nsp->net_ns = copy_net_ns(flags, user_ns, tsk->nsproxy->net_ns); 95 if (IS_ERR(new_nsp->net_ns)) { 96 err = PTR_ERR(new_nsp->net_ns); 97 goto out_net; 98 } 99 100 return new_nsp; 101 102 out_net: 103 if (new_nsp->pid_ns) 104 put_pid_ns(new_nsp->pid_ns); 105 out_pid: 106 if (new_nsp->ipc_ns) 107 put_ipc_ns(new_nsp->ipc_ns); 108 out_ipc: 109 if (new_nsp->uts_ns) 110 put_uts_ns(new_nsp->uts_ns); 111 out_uts: 112 if (new_nsp->mnt_ns) 113 put_mnt_ns(new_nsp->mnt_ns); 114 out_ns: 115 kmem_cache_free(nsproxy_cachep, new_nsp); 116 return ERR_PTR(err); 117 } 118 119 /* 120 * called from clone. This now handles copy for nsproxy and all 121 * namespaces therein. 122 */ 123 int copy_namespaces(unsigned long flags, struct task_struct *tsk) 124 { 125 struct nsproxy *old_ns = tsk->nsproxy; 126 struct user_namespace *user_ns = task_cred_xxx(tsk, user_ns); 127 struct nsproxy *new_ns; 128 int err = 0; 129 130 if (!old_ns) 131 return 0; 132 133 get_nsproxy(old_ns); 134 135 if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | 136 CLONE_NEWPID | CLONE_NEWNET))) 137 return 0; 138 139 if (!ns_capable(user_ns, CAP_SYS_ADMIN)) { 140 err = -EPERM; 141 goto out; 142 } 143 144 /* 145 * CLONE_NEWIPC must detach from the undolist: after switching 146 * to a new ipc namespace, the semaphore arrays from the old 147 * namespace are unreachable. In clone parlance, CLONE_SYSVSEM 148 * means share undolist with parent, so we must forbid using 149 * it along with CLONE_NEWIPC. 150 */ 151 if ((flags & CLONE_NEWIPC) && (flags & CLONE_SYSVSEM)) { 152 err = -EINVAL; 153 goto out; 154 } 155 156 new_ns = create_new_namespaces(flags, tsk, user_ns, tsk->fs); 157 if (IS_ERR(new_ns)) { 158 err = PTR_ERR(new_ns); 159 goto out; 160 } 161 162 tsk->nsproxy = new_ns; 163 164 out: 165 put_nsproxy(old_ns); 166 return err; 167 } 168 169 void free_nsproxy(struct nsproxy *ns) 170 { 171 if (ns->mnt_ns) 172 put_mnt_ns(ns->mnt_ns); 173 if (ns->uts_ns) 174 put_uts_ns(ns->uts_ns); 175 if (ns->ipc_ns) 176 put_ipc_ns(ns->ipc_ns); 177 if (ns->pid_ns) 178 put_pid_ns(ns->pid_ns); 179 put_net(ns->net_ns); 180 kmem_cache_free(nsproxy_cachep, ns); 181 } 182 183 /* 184 * Called from unshare. Unshare all the namespaces part of nsproxy. 185 * On success, returns the new nsproxy. 186 */ 187 int unshare_nsproxy_namespaces(unsigned long unshare_flags, 188 struct nsproxy **new_nsp, struct cred *new_cred, struct fs_struct *new_fs) 189 { 190 struct user_namespace *user_ns; 191 int err = 0; 192 193 if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | 194 CLONE_NEWNET | CLONE_NEWPID))) 195 return 0; 196 197 user_ns = new_cred ? new_cred->user_ns : current_user_ns(); 198 if (!ns_capable(user_ns, CAP_SYS_ADMIN)) 199 return -EPERM; 200 201 *new_nsp = create_new_namespaces(unshare_flags, current, user_ns, 202 new_fs ? new_fs : current->fs); 203 if (IS_ERR(*new_nsp)) { 204 err = PTR_ERR(*new_nsp); 205 goto out; 206 } 207 208 out: 209 return err; 210 } 211 212 void switch_task_namespaces(struct task_struct *p, struct nsproxy *new) 213 { 214 struct nsproxy *ns; 215 216 might_sleep(); 217 218 ns = p->nsproxy; 219 220 rcu_assign_pointer(p->nsproxy, new); 221 222 if (ns && atomic_dec_and_test(&ns->count)) { 223 /* 224 * wait for others to get what they want from this nsproxy. 225 * 226 * cannot release this nsproxy via the call_rcu() since 227 * put_mnt_ns() will want to sleep 228 */ 229 synchronize_rcu(); 230 free_nsproxy(ns); 231 } 232 } 233 234 void exit_task_namespaces(struct task_struct *p) 235 { 236 switch_task_namespaces(p, NULL); 237 } 238 239 SYSCALL_DEFINE2(setns, int, fd, int, nstype) 240 { 241 const struct proc_ns_operations *ops; 242 struct task_struct *tsk = current; 243 struct nsproxy *new_nsproxy; 244 struct proc_ns *ei; 245 struct file *file; 246 int err; 247 248 file = proc_ns_fget(fd); 249 if (IS_ERR(file)) 250 return PTR_ERR(file); 251 252 err = -EINVAL; 253 ei = get_proc_ns(file_inode(file)); 254 ops = ei->ns_ops; 255 if (nstype && (ops->type != nstype)) 256 goto out; 257 258 new_nsproxy = create_new_namespaces(0, tsk, current_user_ns(), tsk->fs); 259 if (IS_ERR(new_nsproxy)) { 260 err = PTR_ERR(new_nsproxy); 261 goto out; 262 } 263 264 err = ops->install(new_nsproxy, ei->ns); 265 if (err) { 266 free_nsproxy(new_nsproxy); 267 goto out; 268 } 269 switch_task_namespaces(tsk, new_nsproxy); 270 out: 271 fput(file); 272 return err; 273 } 274 275 int __init nsproxy_cache_init(void) 276 { 277 nsproxy_cachep = KMEM_CACHE(nsproxy, SLAB_PANIC); 278 return 0; 279 } 280