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 static inline void get_nsproxy(struct nsproxy *ns) 30 { 31 atomic_inc(&ns->count); 32 } 33 34 void 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 */ 45 static 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 */ 62 static 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 new_nsp->net_ns = copy_net_ns(flags, tsk->nsproxy->net_ns); 103 if (IS_ERR(new_nsp->net_ns)) { 104 err = PTR_ERR(new_nsp->net_ns); 105 goto out_net; 106 } 107 108 return new_nsp; 109 110 out_net: 111 if (new_nsp->user_ns) 112 put_user_ns(new_nsp->user_ns); 113 out_user: 114 if (new_nsp->pid_ns) 115 put_pid_ns(new_nsp->pid_ns); 116 out_pid: 117 if (new_nsp->ipc_ns) 118 put_ipc_ns(new_nsp->ipc_ns); 119 out_ipc: 120 if (new_nsp->uts_ns) 121 put_uts_ns(new_nsp->uts_ns); 122 out_uts: 123 if (new_nsp->mnt_ns) 124 put_mnt_ns(new_nsp->mnt_ns); 125 out_ns: 126 kmem_cache_free(nsproxy_cachep, new_nsp); 127 return ERR_PTR(err); 128 } 129 130 /* 131 * called from clone. This now handles copy for nsproxy and all 132 * namespaces therein. 133 */ 134 int copy_namespaces(unsigned long flags, struct task_struct *tsk) 135 { 136 struct nsproxy *old_ns = tsk->nsproxy; 137 struct nsproxy *new_ns; 138 int err = 0; 139 140 if (!old_ns) 141 return 0; 142 143 get_nsproxy(old_ns); 144 145 if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | CLONE_NEWUSER | CLONE_NEWNET))) 146 return 0; 147 148 if (!capable(CAP_SYS_ADMIN)) { 149 err = -EPERM; 150 goto out; 151 } 152 153 new_ns = create_new_namespaces(flags, tsk, tsk->fs); 154 if (IS_ERR(new_ns)) { 155 err = PTR_ERR(new_ns); 156 goto out; 157 } 158 159 tsk->nsproxy = new_ns; 160 out: 161 put_nsproxy(old_ns); 162 return err; 163 } 164 165 void free_nsproxy(struct nsproxy *ns) 166 { 167 if (ns->mnt_ns) 168 put_mnt_ns(ns->mnt_ns); 169 if (ns->uts_ns) 170 put_uts_ns(ns->uts_ns); 171 if (ns->ipc_ns) 172 put_ipc_ns(ns->ipc_ns); 173 if (ns->pid_ns) 174 put_pid_ns(ns->pid_ns); 175 if (ns->user_ns) 176 put_user_ns(ns->user_ns); 177 put_net(ns->net_ns); 178 kmem_cache_free(nsproxy_cachep, ns); 179 } 180 181 /* 182 * Called from unshare. Unshare all the namespaces part of nsproxy. 183 * On success, returns the new nsproxy. 184 */ 185 int unshare_nsproxy_namespaces(unsigned long unshare_flags, 186 struct nsproxy **new_nsp, struct fs_struct *new_fs) 187 { 188 int err = 0; 189 190 if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | 191 CLONE_NEWUSER | CLONE_NEWNET))) 192 return 0; 193 194 if (!capable(CAP_SYS_ADMIN)) 195 return -EPERM; 196 197 *new_nsp = create_new_namespaces(unshare_flags, current, 198 new_fs ? new_fs : current->fs); 199 if (IS_ERR(*new_nsp)) 200 err = PTR_ERR(*new_nsp); 201 return err; 202 } 203 204 static int __init nsproxy_cache_init(void) 205 { 206 nsproxy_cachep = kmem_cache_create("nsproxy", sizeof(struct nsproxy), 207 0, SLAB_PANIC, NULL); 208 return 0; 209 } 210 211 module_init(nsproxy_cache_init); 212