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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> |
f719ff9b | 17 | #include <linux/sched/task.h> |
ae5e1b22 PE |
18 | |
19 | #include "util.h" | |
20 | ||
aba35661 EB |
21 | static struct ucounts *inc_ipc_namespaces(struct user_namespace *ns) |
22 | { | |
23 | return inc_ucount(ns, current_euid(), UCOUNT_IPC_NAMESPACES); | |
24 | } | |
25 | ||
26 | static void dec_ipc_namespaces(struct ucounts *ucounts) | |
27 | { | |
28 | dec_ucount(ucounts, UCOUNT_IPC_NAMESPACES); | |
29 | } | |
30 | ||
bcf58e72 | 31 | static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns, |
b0e77598 | 32 | struct ipc_namespace *old_ns) |
ae5e1b22 | 33 | { |
ae5e1b22 | 34 | struct ipc_namespace *ns; |
aba35661 | 35 | struct ucounts *ucounts; |
7eafd7c7 | 36 | int err; |
ae5e1b22 | 37 | |
df75e774 | 38 | err = -ENOSPC; |
aba35661 EB |
39 | ucounts = inc_ipc_namespaces(user_ns); |
40 | if (!ucounts) | |
41 | goto fail; | |
42 | ||
43 | err = -ENOMEM; | |
ae5e1b22 PE |
44 | ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL); |
45 | if (ns == NULL) | |
aba35661 | 46 | goto fail_dec; |
ae5e1b22 | 47 | |
6344c433 | 48 | err = ns_alloc_inum(&ns->ns); |
aba35661 EB |
49 | if (err) |
50 | goto fail_free; | |
33c42940 | 51 | ns->ns.ops = &ipcns_operations; |
98f842e6 | 52 | |
a2e0602c | 53 | refcount_set(&ns->count, 1); |
b236017a | 54 | ns->user_ns = get_user_ns(user_ns); |
aba35661 | 55 | ns->ucounts = ucounts; |
b236017a | 56 | |
0cfb6aee | 57 | err = sem_init_ns(ns); |
aba35661 EB |
58 | if (err) |
59 | goto fail_put; | |
0cfb6aee GK |
60 | err = msg_init_ns(ns); |
61 | if (err) | |
62 | goto fail_destroy_sem; | |
63 | err = shm_init_ns(ns); | |
64 | if (err) | |
65 | goto fail_destroy_msg; | |
4d89dc6a | 66 | |
0cfb6aee GK |
67 | err = mq_init_ns(ns); |
68 | if (err) | |
69 | goto fail_destroy_shm; | |
ae5e1b22 | 70 | |
ae5e1b22 | 71 | return ns; |
aba35661 | 72 | |
0cfb6aee GK |
73 | fail_destroy_shm: |
74 | shm_exit_ns(ns); | |
75 | fail_destroy_msg: | |
76 | msg_exit_ns(ns); | |
77 | fail_destroy_sem: | |
78 | sem_exit_ns(ns); | |
aba35661 EB |
79 | fail_put: |
80 | put_user_ns(ns->user_ns); | |
81 | ns_free_inum(&ns->ns); | |
82 | fail_free: | |
83 | kfree(ns); | |
84 | fail_dec: | |
85 | dec_ipc_namespaces(ucounts); | |
86 | fail: | |
87 | return ERR_PTR(err); | |
ae5e1b22 PE |
88 | } |
89 | ||
b0e77598 | 90 | struct ipc_namespace *copy_ipcs(unsigned long flags, |
bcf58e72 | 91 | struct user_namespace *user_ns, struct ipc_namespace *ns) |
ae5e1b22 | 92 | { |
ae5e1b22 | 93 | if (!(flags & CLONE_NEWIPC)) |
64424289 | 94 | return get_ipc_ns(ns); |
bcf58e72 | 95 | return create_ipc_ns(user_ns, ns); |
ae5e1b22 PE |
96 | } |
97 | ||
01b8b07a PP |
98 | /* |
99 | * free_ipcs - free all ipcs of one type | |
100 | * @ns: the namespace to remove the ipcs from | |
101 | * @ids: the table of ipcs to free | |
102 | * @free: the function called to free each individual ipc | |
103 | * | |
104 | * Called for each kind of ipc when an ipc_namespace exits. | |
105 | */ | |
106 | void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids, | |
107 | void (*free)(struct ipc_namespace *, struct kern_ipc_perm *)) | |
108 | { | |
109 | struct kern_ipc_perm *perm; | |
110 | int next_id; | |
111 | int total, in_use; | |
112 | ||
d9a605e4 | 113 | down_write(&ids->rwsem); |
01b8b07a PP |
114 | |
115 | in_use = ids->in_use; | |
116 | ||
117 | for (total = 0, next_id = 0; total < in_use; next_id++) { | |
118 | perm = idr_find(&ids->ipcs_idr, next_id); | |
119 | if (perm == NULL) | |
120 | continue; | |
32a27500 DB |
121 | rcu_read_lock(); |
122 | ipc_lock_object(perm); | |
01b8b07a PP |
123 | free(ns, perm); |
124 | total++; | |
125 | } | |
d9a605e4 | 126 | up_write(&ids->rwsem); |
01b8b07a PP |
127 | } |
128 | ||
b4188def AD |
129 | static void free_ipc_ns(struct ipc_namespace *ns) |
130 | { | |
b4188def AD |
131 | sem_exit_ns(ns); |
132 | msg_exit_ns(ns); | |
133 | shm_exit_ns(ns); | |
b4188def | 134 | |
aba35661 | 135 | dec_ipc_namespaces(ns->ucounts); |
b515498f | 136 | put_user_ns(ns->user_ns); |
6344c433 | 137 | ns_free_inum(&ns->ns); |
be4d250a | 138 | kfree(ns); |
b4188def AD |
139 | } |
140 | ||
7eafd7c7 SH |
141 | /* |
142 | * put_ipc_ns - drop a reference to an ipc namespace. | |
143 | * @ns: the namespace to put | |
144 | * | |
145 | * If this is the last task in the namespace exiting, and | |
146 | * it is dropping the refcount to 0, then it can race with | |
147 | * a task in another ipc namespace but in a mounts namespace | |
148 | * which has this ipcns's mqueuefs mounted, doing some action | |
149 | * with one of the mqueuefs files. That can raise the refcount. | |
150 | * So dropping the refcount, and raising the refcount when | |
151 | * accessing it through the VFS, are protected with mq_lock. | |
152 | * | |
153 | * (Clearly, a task raising the refcount on its own ipc_ns | |
154 | * needn't take mq_lock since it can't race with the last task | |
155 | * in the ipcns exiting). | |
156 | */ | |
157 | void put_ipc_ns(struct ipc_namespace *ns) | |
ae5e1b22 | 158 | { |
a2e0602c | 159 | if (refcount_dec_and_lock(&ns->count, &mq_lock)) { |
7eafd7c7 SH |
160 | mq_clear_sbinfo(ns); |
161 | spin_unlock(&mq_lock); | |
162 | mq_put_mnt(ns); | |
163 | free_ipc_ns(ns); | |
164 | } | |
165 | } | |
a00eaf11 | 166 | |
3c041184 AV |
167 | static inline struct ipc_namespace *to_ipc_ns(struct ns_common *ns) |
168 | { | |
169 | return container_of(ns, struct ipc_namespace, ns); | |
170 | } | |
171 | ||
64964528 | 172 | static struct ns_common *ipcns_get(struct task_struct *task) |
a00eaf11 EB |
173 | { |
174 | struct ipc_namespace *ns = NULL; | |
175 | struct nsproxy *nsproxy; | |
176 | ||
728dba3a EB |
177 | task_lock(task); |
178 | nsproxy = task->nsproxy; | |
a00eaf11 EB |
179 | if (nsproxy) |
180 | ns = get_ipc_ns(nsproxy->ipc_ns); | |
728dba3a | 181 | task_unlock(task); |
a00eaf11 | 182 | |
3c041184 | 183 | return ns ? &ns->ns : NULL; |
a00eaf11 EB |
184 | } |
185 | ||
64964528 | 186 | static void ipcns_put(struct ns_common *ns) |
a00eaf11 | 187 | { |
3c041184 | 188 | return put_ipc_ns(to_ipc_ns(ns)); |
a00eaf11 EB |
189 | } |
190 | ||
64964528 | 191 | static int ipcns_install(struct nsproxy *nsproxy, struct ns_common *new) |
a00eaf11 | 192 | { |
3c041184 | 193 | struct ipc_namespace *ns = to_ipc_ns(new); |
5e4a0847 | 194 | if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) || |
c7b96acf | 195 | !ns_capable(current_user_ns(), CAP_SYS_ADMIN)) |
142e1d1d EB |
196 | return -EPERM; |
197 | ||
a00eaf11 EB |
198 | /* Ditch state from the old ipc namespace */ |
199 | exit_sem(current); | |
200 | put_ipc_ns(nsproxy->ipc_ns); | |
201 | nsproxy->ipc_ns = get_ipc_ns(ns); | |
202 | return 0; | |
203 | } | |
204 | ||
bcac25a5 AV |
205 | static struct user_namespace *ipcns_owner(struct ns_common *ns) |
206 | { | |
207 | return to_ipc_ns(ns)->user_ns; | |
208 | } | |
209 | ||
a00eaf11 EB |
210 | const struct proc_ns_operations ipcns_operations = { |
211 | .name = "ipc", | |
212 | .type = CLONE_NEWIPC, | |
213 | .get = ipcns_get, | |
214 | .put = ipcns_put, | |
215 | .install = ipcns_install, | |
bcac25a5 | 216 | .owner = ipcns_owner, |
a00eaf11 | 217 | }; |