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