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Commit | Line | Data |
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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> | |
5b825c3a | 12 | #include <linux/cred.h> |
7eafd7c7 SH |
13 | #include <linux/fs.h> |
14 | #include <linux/mount.h> | |
b515498f | 15 | #include <linux/user_namespace.h> |
0bb80f24 | 16 | #include <linux/proc_ns.h> |
ae5e1b22 PE |
17 | |
18 | #include "util.h" | |
19 | ||
aba35661 EB |
20 | static struct ucounts *inc_ipc_namespaces(struct user_namespace *ns) |
21 | { | |
22 | return inc_ucount(ns, current_euid(), UCOUNT_IPC_NAMESPACES); | |
23 | } | |
24 | ||
25 | static void dec_ipc_namespaces(struct ucounts *ucounts) | |
26 | { | |
27 | dec_ucount(ucounts, UCOUNT_IPC_NAMESPACES); | |
28 | } | |
29 | ||
bcf58e72 | 30 | static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns, |
b0e77598 | 31 | struct ipc_namespace *old_ns) |
ae5e1b22 | 32 | { |
ae5e1b22 | 33 | struct ipc_namespace *ns; |
aba35661 | 34 | struct ucounts *ucounts; |
7eafd7c7 | 35 | int err; |
ae5e1b22 | 36 | |
df75e774 | 37 | err = -ENOSPC; |
aba35661 EB |
38 | ucounts = inc_ipc_namespaces(user_ns); |
39 | if (!ucounts) | |
40 | goto fail; | |
41 | ||
42 | err = -ENOMEM; | |
ae5e1b22 PE |
43 | ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL); |
44 | if (ns == NULL) | |
aba35661 | 45 | goto fail_dec; |
ae5e1b22 | 46 | |
6344c433 | 47 | err = ns_alloc_inum(&ns->ns); |
aba35661 EB |
48 | if (err) |
49 | goto fail_free; | |
33c42940 | 50 | ns->ns.ops = &ipcns_operations; |
98f842e6 | 51 | |
7eafd7c7 | 52 | atomic_set(&ns->count, 1); |
b236017a | 53 | ns->user_ns = get_user_ns(user_ns); |
aba35661 | 54 | ns->ucounts = ucounts; |
b236017a | 55 | |
7eafd7c7 | 56 | err = mq_init_ns(ns); |
aba35661 EB |
57 | if (err) |
58 | goto fail_put; | |
4d89dc6a | 59 | |
ed2ddbf8 PP |
60 | sem_init_ns(ns); |
61 | msg_init_ns(ns); | |
62 | shm_init_ns(ns); | |
ae5e1b22 | 63 | |
ae5e1b22 | 64 | return ns; |
aba35661 EB |
65 | |
66 | fail_put: | |
67 | put_user_ns(ns->user_ns); | |
68 | ns_free_inum(&ns->ns); | |
69 | fail_free: | |
70 | kfree(ns); | |
71 | fail_dec: | |
72 | dec_ipc_namespaces(ucounts); | |
73 | fail: | |
74 | return ERR_PTR(err); | |
ae5e1b22 PE |
75 | } |
76 | ||
b0e77598 | 77 | struct ipc_namespace *copy_ipcs(unsigned long flags, |
bcf58e72 | 78 | struct user_namespace *user_ns, struct ipc_namespace *ns) |
ae5e1b22 | 79 | { |
ae5e1b22 | 80 | if (!(flags & CLONE_NEWIPC)) |
64424289 | 81 | return get_ipc_ns(ns); |
bcf58e72 | 82 | return create_ipc_ns(user_ns, ns); |
ae5e1b22 PE |
83 | } |
84 | ||
01b8b07a PP |
85 | /* |
86 | * free_ipcs - free all ipcs of one type | |
87 | * @ns: the namespace to remove the ipcs from | |
88 | * @ids: the table of ipcs to free | |
89 | * @free: the function called to free each individual ipc | |
90 | * | |
91 | * Called for each kind of ipc when an ipc_namespace exits. | |
92 | */ | |
93 | void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids, | |
94 | void (*free)(struct ipc_namespace *, struct kern_ipc_perm *)) | |
95 | { | |
96 | struct kern_ipc_perm *perm; | |
97 | int next_id; | |
98 | int total, in_use; | |
99 | ||
d9a605e4 | 100 | down_write(&ids->rwsem); |
01b8b07a PP |
101 | |
102 | in_use = ids->in_use; | |
103 | ||
104 | for (total = 0, next_id = 0; total < in_use; next_id++) { | |
105 | perm = idr_find(&ids->ipcs_idr, next_id); | |
106 | if (perm == NULL) | |
107 | continue; | |
32a27500 DB |
108 | rcu_read_lock(); |
109 | ipc_lock_object(perm); | |
01b8b07a PP |
110 | free(ns, perm); |
111 | total++; | |
112 | } | |
d9a605e4 | 113 | up_write(&ids->rwsem); |
01b8b07a PP |
114 | } |
115 | ||
b4188def AD |
116 | static void free_ipc_ns(struct ipc_namespace *ns) |
117 | { | |
b4188def AD |
118 | sem_exit_ns(ns); |
119 | msg_exit_ns(ns); | |
120 | shm_exit_ns(ns); | |
b4188def | 121 | |
aba35661 | 122 | dec_ipc_namespaces(ns->ucounts); |
b515498f | 123 | put_user_ns(ns->user_ns); |
6344c433 | 124 | ns_free_inum(&ns->ns); |
be4d250a | 125 | kfree(ns); |
b4188def AD |
126 | } |
127 | ||
7eafd7c7 SH |
128 | /* |
129 | * put_ipc_ns - drop a reference to an ipc namespace. | |
130 | * @ns: the namespace to put | |
131 | * | |
132 | * If this is the last task in the namespace exiting, and | |
133 | * it is dropping the refcount to 0, then it can race with | |
134 | * a task in another ipc namespace but in a mounts namespace | |
135 | * which has this ipcns's mqueuefs mounted, doing some action | |
136 | * with one of the mqueuefs files. That can raise the refcount. | |
137 | * So dropping the refcount, and raising the refcount when | |
138 | * accessing it through the VFS, are protected with mq_lock. | |
139 | * | |
140 | * (Clearly, a task raising the refcount on its own ipc_ns | |
141 | * needn't take mq_lock since it can't race with the last task | |
142 | * in the ipcns exiting). | |
143 | */ | |
144 | void put_ipc_ns(struct ipc_namespace *ns) | |
ae5e1b22 | 145 | { |
7eafd7c7 SH |
146 | if (atomic_dec_and_lock(&ns->count, &mq_lock)) { |
147 | mq_clear_sbinfo(ns); | |
148 | spin_unlock(&mq_lock); | |
149 | mq_put_mnt(ns); | |
150 | free_ipc_ns(ns); | |
151 | } | |
152 | } | |
a00eaf11 | 153 | |
3c041184 AV |
154 | static inline struct ipc_namespace *to_ipc_ns(struct ns_common *ns) |
155 | { | |
156 | return container_of(ns, struct ipc_namespace, ns); | |
157 | } | |
158 | ||
64964528 | 159 | static struct ns_common *ipcns_get(struct task_struct *task) |
a00eaf11 EB |
160 | { |
161 | struct ipc_namespace *ns = NULL; | |
162 | struct nsproxy *nsproxy; | |
163 | ||
728dba3a EB |
164 | task_lock(task); |
165 | nsproxy = task->nsproxy; | |
a00eaf11 EB |
166 | if (nsproxy) |
167 | ns = get_ipc_ns(nsproxy->ipc_ns); | |
728dba3a | 168 | task_unlock(task); |
a00eaf11 | 169 | |
3c041184 | 170 | return ns ? &ns->ns : NULL; |
a00eaf11 EB |
171 | } |
172 | ||
64964528 | 173 | static void ipcns_put(struct ns_common *ns) |
a00eaf11 | 174 | { |
3c041184 | 175 | return put_ipc_ns(to_ipc_ns(ns)); |
a00eaf11 EB |
176 | } |
177 | ||
64964528 | 178 | static int ipcns_install(struct nsproxy *nsproxy, struct ns_common *new) |
a00eaf11 | 179 | { |
3c041184 | 180 | struct ipc_namespace *ns = to_ipc_ns(new); |
5e4a0847 | 181 | if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) || |
c7b96acf | 182 | !ns_capable(current_user_ns(), CAP_SYS_ADMIN)) |
142e1d1d EB |
183 | return -EPERM; |
184 | ||
a00eaf11 EB |
185 | /* Ditch state from the old ipc namespace */ |
186 | exit_sem(current); | |
187 | put_ipc_ns(nsproxy->ipc_ns); | |
188 | nsproxy->ipc_ns = get_ipc_ns(ns); | |
189 | return 0; | |
190 | } | |
191 | ||
bcac25a5 AV |
192 | static struct user_namespace *ipcns_owner(struct ns_common *ns) |
193 | { | |
194 | return to_ipc_ns(ns)->user_ns; | |
195 | } | |
196 | ||
a00eaf11 EB |
197 | const struct proc_ns_operations ipcns_operations = { |
198 | .name = "ipc", | |
199 | .type = CLONE_NEWIPC, | |
200 | .get = ipcns_get, | |
201 | .put = ipcns_put, | |
202 | .install = ipcns_install, | |
bcac25a5 | 203 | .owner = ipcns_owner, |
a00eaf11 | 204 | }; |