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ae5e1b22 PE |
1 | /* |
2 | * linux/ipc/namespace.c | |
3 | * Copyright (C) 2006 Pavel Emelyanov <xemul@openvz.org> OpenVZ, SWsoft Inc. | |
4 | */ | |
5 | ||
6 | #include <linux/ipc.h> | |
7 | #include <linux/msg.h> | |
8 | #include <linux/ipc_namespace.h> | |
9 | #include <linux/rcupdate.h> | |
10 | #include <linux/nsproxy.h> | |
11 | #include <linux/slab.h> | |
7eafd7c7 SH |
12 | #include <linux/fs.h> |
13 | #include <linux/mount.h> | |
b515498f | 14 | #include <linux/user_namespace.h> |
0bb80f24 | 15 | #include <linux/proc_ns.h> |
ae5e1b22 PE |
16 | |
17 | #include "util.h" | |
18 | ||
bcf58e72 | 19 | static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns, |
b0e77598 | 20 | struct ipc_namespace *old_ns) |
ae5e1b22 | 21 | { |
ae5e1b22 | 22 | struct ipc_namespace *ns; |
7eafd7c7 | 23 | int err; |
ae5e1b22 | 24 | |
ae5e1b22 PE |
25 | ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL); |
26 | if (ns == NULL) | |
ed2ddbf8 | 27 | return ERR_PTR(-ENOMEM); |
ae5e1b22 | 28 | |
6344c433 | 29 | err = ns_alloc_inum(&ns->ns); |
98f842e6 EB |
30 | if (err) { |
31 | kfree(ns); | |
32 | return ERR_PTR(err); | |
33 | } | |
33c42940 | 34 | ns->ns.ops = &ipcns_operations; |
98f842e6 | 35 | |
7eafd7c7 | 36 | atomic_set(&ns->count, 1); |
b236017a EB |
37 | ns->user_ns = get_user_ns(user_ns); |
38 | ||
7eafd7c7 SH |
39 | err = mq_init_ns(ns); |
40 | if (err) { | |
b236017a | 41 | put_user_ns(ns->user_ns); |
6344c433 | 42 | ns_free_inum(&ns->ns); |
7eafd7c7 SH |
43 | kfree(ns); |
44 | return ERR_PTR(err); | |
45 | } | |
4d89dc6a | 46 | |
ed2ddbf8 PP |
47 | sem_init_ns(ns); |
48 | msg_init_ns(ns); | |
49 | shm_init_ns(ns); | |
ae5e1b22 | 50 | |
ae5e1b22 | 51 | return ns; |
ae5e1b22 PE |
52 | } |
53 | ||
b0e77598 | 54 | struct ipc_namespace *copy_ipcs(unsigned long flags, |
bcf58e72 | 55 | struct user_namespace *user_ns, struct ipc_namespace *ns) |
ae5e1b22 | 56 | { |
ae5e1b22 | 57 | if (!(flags & CLONE_NEWIPC)) |
64424289 | 58 | return get_ipc_ns(ns); |
bcf58e72 | 59 | return create_ipc_ns(user_ns, ns); |
ae5e1b22 PE |
60 | } |
61 | ||
01b8b07a PP |
62 | /* |
63 | * free_ipcs - free all ipcs of one type | |
64 | * @ns: the namespace to remove the ipcs from | |
65 | * @ids: the table of ipcs to free | |
66 | * @free: the function called to free each individual ipc | |
67 | * | |
68 | * Called for each kind of ipc when an ipc_namespace exits. | |
69 | */ | |
70 | void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids, | |
71 | void (*free)(struct ipc_namespace *, struct kern_ipc_perm *)) | |
72 | { | |
73 | struct kern_ipc_perm *perm; | |
74 | int next_id; | |
75 | int total, in_use; | |
76 | ||
d9a605e4 | 77 | down_write(&ids->rwsem); |
01b8b07a PP |
78 | |
79 | in_use = ids->in_use; | |
80 | ||
81 | for (total = 0, next_id = 0; total < in_use; next_id++) { | |
82 | perm = idr_find(&ids->ipcs_idr, next_id); | |
83 | if (perm == NULL) | |
84 | continue; | |
32a27500 DB |
85 | rcu_read_lock(); |
86 | ipc_lock_object(perm); | |
01b8b07a PP |
87 | free(ns, perm); |
88 | total++; | |
89 | } | |
d9a605e4 | 90 | up_write(&ids->rwsem); |
01b8b07a PP |
91 | } |
92 | ||
b4188def AD |
93 | static void free_ipc_ns(struct ipc_namespace *ns) |
94 | { | |
b4188def AD |
95 | sem_exit_ns(ns); |
96 | msg_exit_ns(ns); | |
97 | shm_exit_ns(ns); | |
b4188def | 98 | |
b515498f | 99 | put_user_ns(ns->user_ns); |
6344c433 | 100 | ns_free_inum(&ns->ns); |
be4d250a | 101 | kfree(ns); |
b4188def AD |
102 | } |
103 | ||
7eafd7c7 SH |
104 | /* |
105 | * put_ipc_ns - drop a reference to an ipc namespace. | |
106 | * @ns: the namespace to put | |
107 | * | |
108 | * If this is the last task in the namespace exiting, and | |
109 | * it is dropping the refcount to 0, then it can race with | |
110 | * a task in another ipc namespace but in a mounts namespace | |
111 | * which has this ipcns's mqueuefs mounted, doing some action | |
112 | * with one of the mqueuefs files. That can raise the refcount. | |
113 | * So dropping the refcount, and raising the refcount when | |
114 | * accessing it through the VFS, are protected with mq_lock. | |
115 | * | |
116 | * (Clearly, a task raising the refcount on its own ipc_ns | |
117 | * needn't take mq_lock since it can't race with the last task | |
118 | * in the ipcns exiting). | |
119 | */ | |
120 | void put_ipc_ns(struct ipc_namespace *ns) | |
ae5e1b22 | 121 | { |
7eafd7c7 SH |
122 | if (atomic_dec_and_lock(&ns->count, &mq_lock)) { |
123 | mq_clear_sbinfo(ns); | |
124 | spin_unlock(&mq_lock); | |
125 | mq_put_mnt(ns); | |
126 | free_ipc_ns(ns); | |
127 | } | |
128 | } | |
a00eaf11 | 129 | |
3c041184 AV |
130 | static inline struct ipc_namespace *to_ipc_ns(struct ns_common *ns) |
131 | { | |
132 | return container_of(ns, struct ipc_namespace, ns); | |
133 | } | |
134 | ||
64964528 | 135 | static struct ns_common *ipcns_get(struct task_struct *task) |
a00eaf11 EB |
136 | { |
137 | struct ipc_namespace *ns = NULL; | |
138 | struct nsproxy *nsproxy; | |
139 | ||
728dba3a EB |
140 | task_lock(task); |
141 | nsproxy = task->nsproxy; | |
a00eaf11 EB |
142 | if (nsproxy) |
143 | ns = get_ipc_ns(nsproxy->ipc_ns); | |
728dba3a | 144 | task_unlock(task); |
a00eaf11 | 145 | |
3c041184 | 146 | return ns ? &ns->ns : NULL; |
a00eaf11 EB |
147 | } |
148 | ||
64964528 | 149 | static void ipcns_put(struct ns_common *ns) |
a00eaf11 | 150 | { |
3c041184 | 151 | return put_ipc_ns(to_ipc_ns(ns)); |
a00eaf11 EB |
152 | } |
153 | ||
64964528 | 154 | static int ipcns_install(struct nsproxy *nsproxy, struct ns_common *new) |
a00eaf11 | 155 | { |
3c041184 | 156 | struct ipc_namespace *ns = to_ipc_ns(new); |
5e4a0847 | 157 | if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) || |
c7b96acf | 158 | !ns_capable(current_user_ns(), CAP_SYS_ADMIN)) |
142e1d1d EB |
159 | return -EPERM; |
160 | ||
a00eaf11 EB |
161 | /* Ditch state from the old ipc namespace */ |
162 | exit_sem(current); | |
163 | put_ipc_ns(nsproxy->ipc_ns); | |
164 | nsproxy->ipc_ns = get_ipc_ns(ns); | |
165 | return 0; | |
166 | } | |
167 | ||
168 | const struct proc_ns_operations ipcns_operations = { | |
169 | .name = "ipc", | |
170 | .type = CLONE_NEWIPC, | |
171 | .get = ipcns_get, | |
172 | .put = ipcns_put, | |
173 | .install = ipcns_install, | |
174 | }; |