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