kernel/nsproxy.c

   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(nsproxy, SLAB_PANIC);
 207         return 0;
 208 }
 209
 210 module_init(nsproxy_cache_init);