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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
ae5e1b22 PE |
2 | /* |
3 | * linux/ipc/namespace.c | |
4 | * Copyright (C) 2006 Pavel Emelyanov <xemul@openvz.org> OpenVZ, SWsoft Inc. | |
5 | */ | |
6 | ||
7 | #include <linux/ipc.h> | |
8 | #include <linux/msg.h> | |
9 | #include <linux/ipc_namespace.h> | |
10 | #include <linux/rcupdate.h> | |
11 | #include <linux/nsproxy.h> | |
12 | #include <linux/slab.h> | |
5b825c3a | 13 | #include <linux/cred.h> |
7eafd7c7 SH |
14 | #include <linux/fs.h> |
15 | #include <linux/mount.h> | |
b515498f | 16 | #include <linux/user_namespace.h> |
0bb80f24 | 17 | #include <linux/proc_ns.h> |
f719ff9b | 18 | #include <linux/sched/task.h> |
ae5e1b22 PE |
19 | |
20 | #include "util.h" | |
21 | ||
aba35661 EB |
22 | static struct ucounts *inc_ipc_namespaces(struct user_namespace *ns) |
23 | { | |
24 | return inc_ucount(ns, current_euid(), UCOUNT_IPC_NAMESPACES); | |
25 | } | |
26 | ||
27 | static void dec_ipc_namespaces(struct ucounts *ucounts) | |
28 | { | |
29 | dec_ucount(ucounts, UCOUNT_IPC_NAMESPACES); | |
30 | } | |
31 | ||
bcf58e72 | 32 | static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns, |
b0e77598 | 33 | struct ipc_namespace *old_ns) |
ae5e1b22 | 34 | { |
ae5e1b22 | 35 | struct ipc_namespace *ns; |
aba35661 | 36 | struct ucounts *ucounts; |
7eafd7c7 | 37 | int err; |
ae5e1b22 | 38 | |
df75e774 | 39 | err = -ENOSPC; |
aba35661 EB |
40 | ucounts = inc_ipc_namespaces(user_ns); |
41 | if (!ucounts) | |
42 | goto fail; | |
43 | ||
44 | err = -ENOMEM; | |
30acd0bd | 45 | ns = kzalloc(sizeof(struct ipc_namespace), GFP_KERNEL_ACCOUNT); |
ae5e1b22 | 46 | if (ns == NULL) |
aba35661 | 47 | goto fail_dec; |
ae5e1b22 | 48 | |
6344c433 | 49 | err = ns_alloc_inum(&ns->ns); |
aba35661 EB |
50 | if (err) |
51 | goto fail_free; | |
33c42940 | 52 | ns->ns.ops = &ipcns_operations; |
98f842e6 | 53 | |
137ec390 | 54 | refcount_set(&ns->ns.count, 1); |
b236017a | 55 | ns->user_ns = get_user_ns(user_ns); |
aba35661 | 56 | ns->ucounts = ucounts; |
b236017a | 57 | |
eae04d25 | 58 | err = mq_init_ns(ns); |
aba35661 EB |
59 | if (err) |
60 | goto fail_put; | |
4d89dc6a | 61 | |
dc55e35f AG |
62 | err = -ENOMEM; |
63 | if (!setup_mq_sysctls(ns)) | |
64 | goto fail_put; | |
65 | ||
1f5c135e AG |
66 | if (!setup_ipc_sysctls(ns)) |
67 | goto fail_put; | |
68 | ||
eae04d25 DB |
69 | sem_init_ns(ns); |
70 | msg_init_ns(ns); | |
71 | shm_init_ns(ns); | |
ae5e1b22 | 72 | |
ae5e1b22 | 73 | return ns; |
aba35661 EB |
74 | |
75 | fail_put: | |
76 | put_user_ns(ns->user_ns); | |
77 | ns_free_inum(&ns->ns); | |
78 | fail_free: | |
79 | kfree(ns); | |
80 | fail_dec: | |
81 | dec_ipc_namespaces(ucounts); | |
82 | fail: | |
83 | return ERR_PTR(err); | |
ae5e1b22 PE |
84 | } |
85 | ||
b0e77598 | 86 | struct ipc_namespace *copy_ipcs(unsigned long flags, |
bcf58e72 | 87 | struct user_namespace *user_ns, struct ipc_namespace *ns) |
ae5e1b22 | 88 | { |
ae5e1b22 | 89 | if (!(flags & CLONE_NEWIPC)) |
64424289 | 90 | return get_ipc_ns(ns); |
bcf58e72 | 91 | return create_ipc_ns(user_ns, ns); |
ae5e1b22 PE |
92 | } |
93 | ||
01b8b07a PP |
94 | /* |
95 | * free_ipcs - free all ipcs of one type | |
96 | * @ns: the namespace to remove the ipcs from | |
97 | * @ids: the table of ipcs to free | |
98 | * @free: the function called to free each individual ipc | |
99 | * | |
100 | * Called for each kind of ipc when an ipc_namespace exits. | |
101 | */ | |
102 | void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids, | |
103 | void (*free)(struct ipc_namespace *, struct kern_ipc_perm *)) | |
104 | { | |
105 | struct kern_ipc_perm *perm; | |
106 | int next_id; | |
107 | int total, in_use; | |
108 | ||
d9a605e4 | 109 | down_write(&ids->rwsem); |
01b8b07a PP |
110 | |
111 | in_use = ids->in_use; | |
112 | ||
113 | for (total = 0, next_id = 0; total < in_use; next_id++) { | |
114 | perm = idr_find(&ids->ipcs_idr, next_id); | |
115 | if (perm == NULL) | |
116 | continue; | |
32a27500 DB |
117 | rcu_read_lock(); |
118 | ipc_lock_object(perm); | |
01b8b07a PP |
119 | free(ns, perm); |
120 | total++; | |
121 | } | |
d9a605e4 | 122 | up_write(&ids->rwsem); |
01b8b07a PP |
123 | } |
124 | ||
b4188def AD |
125 | static void free_ipc_ns(struct ipc_namespace *ns) |
126 | { | |
e1eb26fa GS |
127 | /* mq_put_mnt() waits for a grace period as kern_unmount() |
128 | * uses synchronize_rcu(). | |
129 | */ | |
130 | mq_put_mnt(ns); | |
b4188def AD |
131 | sem_exit_ns(ns); |
132 | msg_exit_ns(ns); | |
133 | shm_exit_ns(ns); | |
b4188def | 134 | |
dc55e35f | 135 | retire_mq_sysctls(ns); |
1f5c135e | 136 | retire_ipc_sysctls(ns); |
dc55e35f | 137 | |
aba35661 | 138 | dec_ipc_namespaces(ns->ucounts); |
b515498f | 139 | put_user_ns(ns->user_ns); |
6344c433 | 140 | ns_free_inum(&ns->ns); |
be4d250a | 141 | kfree(ns); |
b4188def AD |
142 | } |
143 | ||
e1eb26fa GS |
144 | static LLIST_HEAD(free_ipc_list); |
145 | static void free_ipc(struct work_struct *unused) | |
146 | { | |
147 | struct llist_node *node = llist_del_all(&free_ipc_list); | |
148 | struct ipc_namespace *n, *t; | |
149 | ||
150 | llist_for_each_entry_safe(n, t, node, mnt_llist) | |
151 | free_ipc_ns(n); | |
152 | } | |
153 | ||
154 | /* | |
155 | * The work queue is used to avoid the cost of synchronize_rcu in kern_unmount. | |
156 | */ | |
157 | static DECLARE_WORK(free_ipc_work, free_ipc); | |
158 | ||
7eafd7c7 SH |
159 | /* |
160 | * put_ipc_ns - drop a reference to an ipc namespace. | |
161 | * @ns: the namespace to put | |
162 | * | |
163 | * If this is the last task in the namespace exiting, and | |
164 | * it is dropping the refcount to 0, then it can race with | |
165 | * a task in another ipc namespace but in a mounts namespace | |
166 | * which has this ipcns's mqueuefs mounted, doing some action | |
167 | * with one of the mqueuefs files. That can raise the refcount. | |
168 | * So dropping the refcount, and raising the refcount when | |
169 | * accessing it through the VFS, are protected with mq_lock. | |
170 | * | |
171 | * (Clearly, a task raising the refcount on its own ipc_ns | |
172 | * needn't take mq_lock since it can't race with the last task | |
173 | * in the ipcns exiting). | |
174 | */ | |
175 | void put_ipc_ns(struct ipc_namespace *ns) | |
ae5e1b22 | 176 | { |
137ec390 | 177 | if (refcount_dec_and_lock(&ns->ns.count, &mq_lock)) { |
7eafd7c7 SH |
178 | mq_clear_sbinfo(ns); |
179 | spin_unlock(&mq_lock); | |
e1eb26fa GS |
180 | |
181 | if (llist_add(&ns->mnt_llist, &free_ipc_list)) | |
182 | schedule_work(&free_ipc_work); | |
7eafd7c7 SH |
183 | } |
184 | } | |
a00eaf11 | 185 | |
3c041184 AV |
186 | static inline struct ipc_namespace *to_ipc_ns(struct ns_common *ns) |
187 | { | |
188 | return container_of(ns, struct ipc_namespace, ns); | |
189 | } | |
190 | ||
64964528 | 191 | static struct ns_common *ipcns_get(struct task_struct *task) |
a00eaf11 EB |
192 | { |
193 | struct ipc_namespace *ns = NULL; | |
194 | struct nsproxy *nsproxy; | |
195 | ||
728dba3a EB |
196 | task_lock(task); |
197 | nsproxy = task->nsproxy; | |
a00eaf11 EB |
198 | if (nsproxy) |
199 | ns = get_ipc_ns(nsproxy->ipc_ns); | |
728dba3a | 200 | task_unlock(task); |
a00eaf11 | 201 | |
3c041184 | 202 | return ns ? &ns->ns : NULL; |
a00eaf11 EB |
203 | } |
204 | ||
64964528 | 205 | static void ipcns_put(struct ns_common *ns) |
a00eaf11 | 206 | { |
3c041184 | 207 | return put_ipc_ns(to_ipc_ns(ns)); |
a00eaf11 EB |
208 | } |
209 | ||
f2a8d52e | 210 | static int ipcns_install(struct nsset *nsset, struct ns_common *new) |
a00eaf11 | 211 | { |
f2a8d52e | 212 | struct nsproxy *nsproxy = nsset->nsproxy; |
3c041184 | 213 | struct ipc_namespace *ns = to_ipc_ns(new); |
5e4a0847 | 214 | if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) || |
f2a8d52e | 215 | !ns_capable(nsset->cred->user_ns, CAP_SYS_ADMIN)) |
142e1d1d EB |
216 | return -EPERM; |
217 | ||
a00eaf11 EB |
218 | put_ipc_ns(nsproxy->ipc_ns); |
219 | nsproxy->ipc_ns = get_ipc_ns(ns); | |
220 | return 0; | |
221 | } | |
222 | ||
bcac25a5 AV |
223 | static struct user_namespace *ipcns_owner(struct ns_common *ns) |
224 | { | |
225 | return to_ipc_ns(ns)->user_ns; | |
226 | } | |
227 | ||
a00eaf11 EB |
228 | const struct proc_ns_operations ipcns_operations = { |
229 | .name = "ipc", | |
230 | .type = CLONE_NEWIPC, | |
231 | .get = ipcns_get, | |
232 | .put = ipcns_put, | |
233 | .install = ipcns_install, | |
bcac25a5 | 234 | .owner = ipcns_owner, |
a00eaf11 | 235 | }; |