| 1 | |
| 2 | * Copyright (C) 2006 IBM Corporation
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| 3 | *
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| 4 | * Author: Serge Hallyn <[email protected]>
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| 5 | *
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| 6 | * This program is free software; you can redistribute it and/or
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| 7 | * modify it under the terms of the GNU General Public License as
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| 8 | * published by the Free Software Foundation, version 2 of the
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| 9 | * License.
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| 10 | *
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| 11 | * Jun 2006 - namespaces support
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| 12 | * OpenVZ, SWsoft Inc.
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| 13 | * Pavel Emelianov <[email protected]>
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| 14 |
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| 15 |
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| 16 | #include <linux/module.h>
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| 17 | #include <linux/version.h>
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| 18 | #include <linux/nsproxy.h>
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| 19 | #include <linux/init_task.h>
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| 20 | #include <linux/namespace.h>
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| 21 | #include <linux/utsname.h>
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| 22 |
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| 23 | struct nsproxy init_nsproxy = INIT_NSPROXY(init_nsproxy);
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| 24 |
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| 25 | static inline void get_nsproxy(struct nsproxy *ns)
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| 26 | {
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| 27 | atomic_inc(&ns->count);
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| 28 | }
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| 29 |
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| 30 | void get_task_namespaces(struct task_struct *tsk)
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| 31 | {
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| 32 | struct nsproxy *ns = tsk->nsproxy;
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| 33 | if (ns) {
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| 34 | get_nsproxy(ns);
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| 35 | }
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| 36 | }
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| 37 |
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| 38 | |
| 39 | * creates a copy of "orig" with refcount 1.
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| 40 | * This does not grab references to the contained namespaces,
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| 41 | * so that needs to be done by dup_namespaces.
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| 42 |
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| 43 | static inline struct nsproxy *clone_namespaces(struct nsproxy *orig)
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| 44 | {
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| 45 | struct nsproxy *ns;
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| 46 |
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| 47 | ns = kmemdup(orig, sizeof(struct nsproxy), GFP_KERNEL);
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| 48 | if (ns)
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| 49 | atomic_set(&ns->count, 1);
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| 50 | return ns;
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| 51 | }
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| 52 |
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| 53 | |
| 54 | * copies the nsproxy, setting refcount to 1, and grabbing a
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| 55 | * reference to all contained namespaces. Called from
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| 56 | * sys_unshare()
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| 57 |
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| 58 | struct nsproxy *dup_namespaces(struct nsproxy *orig)
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| 59 | {
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| 60 | struct nsproxy *ns = clone_namespaces(orig);
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| 61 |
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| 62 | if (ns) {
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| 63 | if (ns->namespace)
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| 64 | get_namespace(ns->namespace);
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| 65 | if (ns->uts_ns)
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| 66 | get_uts_ns(ns->uts_ns);
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| 67 | if (ns->ipc_ns)
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| 68 | get_ipc_ns(ns->ipc_ns);
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| 69 | }
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| 70 |
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| 71 | return ns;
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| 72 | }
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| 73 |
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| 74 | |
| 75 | * called from clone. This now handles copy for nsproxy and all
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| 76 | * namespaces therein.
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| 77 |
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| 78 | int copy_namespaces(int flags, struct task_struct *tsk)
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| 79 | {
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| 80 | struct nsproxy *old_ns = tsk->nsproxy;
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| 81 | struct nsproxy *new_ns;
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| 82 | int err = 0;
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| 83 |
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| 84 | if (!old_ns)
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| 85 | return 0;
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| 86 |
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| 87 | get_nsproxy(old_ns);
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| 88 |
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| 89 | if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC)))
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| 90 | return 0;
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| 91 |
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| 92 | new_ns = clone_namespaces(old_ns);
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| 93 | if (!new_ns) {
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| 94 | err = -ENOMEM;
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| 95 | goto out;
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| 96 | }
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| 97 |
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| 98 | tsk->nsproxy = new_ns;
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| 99 |
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| 100 | err = copy_namespace(flags, tsk);
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| 101 | if (err)
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| 102 | goto out_ns;
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| 103 |
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| 104 | err = copy_utsname(flags, tsk);
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| 105 | if (err)
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| 106 | goto out_uts;
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| 107 |
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| 108 | err = copy_ipcs(flags, tsk);
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| 109 | if (err)
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| 110 | goto out_ipc;
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| 111 |
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| 112 | out:
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| 113 | put_nsproxy(old_ns);
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| 114 | return err;
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| 115 |
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| 116 | out_ipc:
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| 117 | if (new_ns->uts_ns)
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| 118 | put_uts_ns(new_ns->uts_ns);
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| 119 | out_uts:
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| 120 | if (new_ns->namespace)
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| 121 | put_namespace(new_ns->namespace);
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| 122 | out_ns:
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| 123 | tsk->nsproxy = old_ns;
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| 124 | kfree(new_ns);
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| 125 | goto out;
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| 126 | }
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| 127 |
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| 128 | void free_nsproxy(struct nsproxy *ns)
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| 129 | {
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| 130 | if (ns->namespace)
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| 131 | put_namespace(ns->namespace);
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| 132 | if (ns->uts_ns)
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| 133 | put_uts_ns(ns->uts_ns);
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| 134 | if (ns->ipc_ns)
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| 135 | put_ipc_ns(ns->ipc_ns);
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| 136 | kfree(ns);
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| 137 | }
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