| 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 | } |