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 struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy); 25 26 static inline void get_nsproxy(struct nsproxy *ns) 27 { 28 atomic_inc(&ns->count); 29 } 30 31 void get_task_namespaces(struct task_struct *tsk) 32 { 33 struct nsproxy *ns = tsk->nsproxy; 34 if (ns) { 35 get_nsproxy(ns); 36 } 37 } 38 39 /* 40 * creates a copy of "orig" with refcount 1. 41 */ 42 static inline struct nsproxy *clone_nsproxy(struct nsproxy *orig) 43 { 44 struct nsproxy *ns; 45 46 ns = kmemdup(orig, sizeof(struct nsproxy), GFP_KERNEL); 47 if (ns) 48 atomic_set(&ns->count, 1); 49 return ns; 50 } 51 52 /* 53 * Create new nsproxy and all of its the associated namespaces. 54 * Return the newly created nsproxy. Do not attach this to the task, 55 * leave it to the caller to do proper locking and attach it to task. 56 */ 57 static struct nsproxy *create_new_namespaces(int flags, struct task_struct *tsk, 58 struct fs_struct *new_fs) 59 { 60 struct nsproxy *new_nsp; 61 62 new_nsp = clone_nsproxy(tsk->nsproxy); 63 if (!new_nsp) 64 return ERR_PTR(-ENOMEM); 65 66 new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, new_fs); 67 if (IS_ERR(new_nsp->mnt_ns)) 68 goto out_ns; 69 70 new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns); 71 if (IS_ERR(new_nsp->uts_ns)) 72 goto out_uts; 73 74 new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns); 75 if (IS_ERR(new_nsp->ipc_ns)) 76 goto out_ipc; 77 78 new_nsp->pid_ns = copy_pid_ns(flags, tsk->nsproxy->pid_ns); 79 if (IS_ERR(new_nsp->pid_ns)) 80 goto out_pid; 81 82 return new_nsp; 83 84 out_pid: 85 if (new_nsp->ipc_ns) 86 put_ipc_ns(new_nsp->ipc_ns); 87 out_ipc: 88 if (new_nsp->uts_ns) 89 put_uts_ns(new_nsp->uts_ns); 90 out_uts: 91 if (new_nsp->mnt_ns) 92 put_mnt_ns(new_nsp->mnt_ns); 93 out_ns: 94 kfree(new_nsp); 95 return ERR_PTR(-ENOMEM); 96 } 97 98 /* 99 * called from clone. This now handles copy for nsproxy and all 100 * namespaces therein. 101 */ 102 int copy_namespaces(int flags, struct task_struct *tsk) 103 { 104 struct nsproxy *old_ns = tsk->nsproxy; 105 struct nsproxy *new_ns; 106 int err = 0; 107 108 if (!old_ns) 109 return 0; 110 111 get_nsproxy(old_ns); 112 113 if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC))) 114 return 0; 115 116 if (!capable(CAP_SYS_ADMIN)) { 117 err = -EPERM; 118 goto out; 119 } 120 121 new_ns = create_new_namespaces(flags, tsk, tsk->fs); 122 if (IS_ERR(new_ns)) { 123 err = PTR_ERR(new_ns); 124 goto out; 125 } 126 127 tsk->nsproxy = new_ns; 128 out: 129 put_nsproxy(old_ns); 130 return err; 131 } 132 133 void free_nsproxy(struct nsproxy *ns) 134 { 135 if (ns->mnt_ns) 136 put_mnt_ns(ns->mnt_ns); 137 if (ns->uts_ns) 138 put_uts_ns(ns->uts_ns); 139 if (ns->ipc_ns) 140 put_ipc_ns(ns->ipc_ns); 141 if (ns->pid_ns) 142 put_pid_ns(ns->pid_ns); 143 kfree(ns); 144 } 145 146 /* 147 * Called from unshare. Unshare all the namespaces part of nsproxy. 148 * On sucess, returns the new nsproxy and a reference to old nsproxy 149 * to make sure it stays around. 150 */ 151 int unshare_nsproxy_namespaces(unsigned long unshare_flags, 152 struct nsproxy **new_nsp, struct fs_struct *new_fs) 153 { 154 struct nsproxy *old_ns = current->nsproxy; 155 int err = 0; 156 157 if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC))) 158 return 0; 159 160 #ifndef CONFIG_IPC_NS 161 if (unshare_flags & CLONE_NEWIPC) 162 return -EINVAL; 163 #endif 164 165 #ifndef CONFIG_UTS_NS 166 if (unshare_flags & CLONE_NEWUTS) 167 return -EINVAL; 168 #endif 169 170 if (!capable(CAP_SYS_ADMIN)) 171 return -EPERM; 172 173 get_nsproxy(old_ns); 174 175 *new_nsp = create_new_namespaces(unshare_flags, current, 176 new_fs ? new_fs : current->fs); 177 if (IS_ERR(*new_nsp)) { 178 err = PTR_ERR(*new_nsp); 179 put_nsproxy(old_ns); 180 } 181 return err; 182 } 183