blob: 0abdea496493da66166db5a8b8a24780ade4fc2c [file] [log] [blame]
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -08001/*
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>
Serge E. Hallyn7eafd7c2009-04-06 19:01:10 -070012#include <linux/fs.h>
13#include <linux/mount.h>
Serge E. Hallynb5154982011-03-23 16:43:23 -070014#include <linux/user_namespace.h>
David Howells0bb80f22013-04-12 01:50:06 +010015#include <linux/proc_ns.h>
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -080016
17#include "util.h"
18
Eric W. Biedermanaba35662016-08-08 14:20:23 -050019static struct ucounts *inc_ipc_namespaces(struct user_namespace *ns)
20{
21 return inc_ucount(ns, current_euid(), UCOUNT_IPC_NAMESPACES);
22}
23
24static void dec_ipc_namespaces(struct ucounts *ucounts)
25{
26 dec_ucount(ucounts, UCOUNT_IPC_NAMESPACES);
27}
28
Eric W. Biedermanbcf58e72012-07-26 04:02:49 -070029static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns,
Serge E. Hallynb0e77592011-03-23 16:43:24 -070030 struct ipc_namespace *old_ns)
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -080031{
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -080032 struct ipc_namespace *ns;
Eric W. Biedermanaba35662016-08-08 14:20:23 -050033 struct ucounts *ucounts;
Serge E. Hallyn7eafd7c2009-04-06 19:01:10 -070034 int err;
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -080035
Eric W. Biedermandf75e772016-09-22 13:08:36 -050036 err = -ENOSPC;
Eric W. Biedermanaba35662016-08-08 14:20:23 -050037 ucounts = inc_ipc_namespaces(user_ns);
38 if (!ucounts)
39 goto fail;
40
41 err = -ENOMEM;
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -080042 ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL);
43 if (ns == NULL)
Eric W. Biedermanaba35662016-08-08 14:20:23 -050044 goto fail_dec;
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -080045
Al Viro6344c432014-11-01 00:45:45 -040046 err = ns_alloc_inum(&ns->ns);
Eric W. Biedermanaba35662016-08-08 14:20:23 -050047 if (err)
48 goto fail_free;
Al Viro33c42942014-11-01 02:32:53 -040049 ns->ns.ops = &ipcns_operations;
Eric W. Biederman98f842e2011-06-15 10:21:48 -070050
Serge E. Hallyn7eafd7c2009-04-06 19:01:10 -070051 atomic_set(&ns->count, 1);
Eric W. Biedermanb2360172016-05-31 12:26:41 -050052 ns->user_ns = get_user_ns(user_ns);
Eric W. Biedermanaba35662016-08-08 14:20:23 -050053 ns->ucounts = ucounts;
Eric W. Biedermanb2360172016-05-31 12:26:41 -050054
Serge E. Hallyn7eafd7c2009-04-06 19:01:10 -070055 err = mq_init_ns(ns);
Eric W. Biedermanaba35662016-08-08 14:20:23 -050056 if (err)
57 goto fail_put;
Nadia Derbey4d89dc62008-04-29 01:00:40 -070058
Pierre Peiffered2ddbf2008-02-08 04:18:57 -080059 sem_init_ns(ns);
60 msg_init_ns(ns);
61 shm_init_ns(ns);
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -080062
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -080063 return ns;
Eric W. Biedermanaba35662016-08-08 14:20:23 -050064
65fail_put:
66 put_user_ns(ns->user_ns);
67 ns_free_inum(&ns->ns);
68fail_free:
69 kfree(ns);
70fail_dec:
71 dec_ipc_namespaces(ucounts);
72fail:
73 return ERR_PTR(err);
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -080074}
75
Serge E. Hallynb0e77592011-03-23 16:43:24 -070076struct ipc_namespace *copy_ipcs(unsigned long flags,
Eric W. Biedermanbcf58e72012-07-26 04:02:49 -070077 struct user_namespace *user_ns, struct ipc_namespace *ns)
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -080078{
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -080079 if (!(flags & CLONE_NEWIPC))
Alexey Dobriyan64424282009-06-17 16:27:54 -070080 return get_ipc_ns(ns);
Eric W. Biedermanbcf58e72012-07-26 04:02:49 -070081 return create_ipc_ns(user_ns, ns);
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -080082}
83
Pierre Peiffer01b8b072008-02-08 04:18:57 -080084/*
85 * free_ipcs - free all ipcs of one type
86 * @ns: the namespace to remove the ipcs from
87 * @ids: the table of ipcs to free
88 * @free: the function called to free each individual ipc
89 *
90 * Called for each kind of ipc when an ipc_namespace exits.
91 */
92void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
93 void (*free)(struct ipc_namespace *, struct kern_ipc_perm *))
94{
95 struct kern_ipc_perm *perm;
96 int next_id;
97 int total, in_use;
98
Davidlohr Buesod9a605e2013-09-11 14:26:24 -070099 down_write(&ids->rwsem);
Pierre Peiffer01b8b072008-02-08 04:18:57 -0800100
101 in_use = ids->in_use;
102
103 for (total = 0, next_id = 0; total < in_use; next_id++) {
104 perm = idr_find(&ids->ipcs_idr, next_id);
105 if (perm == NULL)
106 continue;
Davidlohr Bueso32a27502013-09-11 14:26:29 -0700107 rcu_read_lock();
108 ipc_lock_object(perm);
Pierre Peiffer01b8b072008-02-08 04:18:57 -0800109 free(ns, perm);
110 total++;
111 }
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700112 up_write(&ids->rwsem);
Pierre Peiffer01b8b072008-02-08 04:18:57 -0800113}
114
Alexey Dobriyanb4188de2009-06-17 16:27:56 -0700115static void free_ipc_ns(struct ipc_namespace *ns)
116{
Alexey Dobriyanb4188de2009-06-17 16:27:56 -0700117 sem_exit_ns(ns);
118 msg_exit_ns(ns);
119 shm_exit_ns(ns);
Alexey Dobriyanb4188de2009-06-17 16:27:56 -0700120
Eric W. Biedermanaba35662016-08-08 14:20:23 -0500121 dec_ipc_namespaces(ns->ucounts);
Serge E. Hallynb5154982011-03-23 16:43:23 -0700122 put_user_ns(ns->user_ns);
Al Viro6344c432014-11-01 00:45:45 -0400123 ns_free_inum(&ns->ns);
Xiaotian Fengbe4d2502011-03-25 01:57:01 -0700124 kfree(ns);
Alexey Dobriyanb4188de2009-06-17 16:27:56 -0700125}
126
Serge E. Hallyn7eafd7c2009-04-06 19:01:10 -0700127/*
128 * put_ipc_ns - drop a reference to an ipc namespace.
129 * @ns: the namespace to put
130 *
131 * If this is the last task in the namespace exiting, and
132 * it is dropping the refcount to 0, then it can race with
133 * a task in another ipc namespace but in a mounts namespace
134 * which has this ipcns's mqueuefs mounted, doing some action
135 * with one of the mqueuefs files. That can raise the refcount.
136 * So dropping the refcount, and raising the refcount when
137 * accessing it through the VFS, are protected with mq_lock.
138 *
139 * (Clearly, a task raising the refcount on its own ipc_ns
140 * needn't take mq_lock since it can't race with the last task
141 * in the ipcns exiting).
142 */
143void put_ipc_ns(struct ipc_namespace *ns)
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800144{
Serge E. Hallyn7eafd7c2009-04-06 19:01:10 -0700145 if (atomic_dec_and_lock(&ns->count, &mq_lock)) {
146 mq_clear_sbinfo(ns);
147 spin_unlock(&mq_lock);
148 mq_put_mnt(ns);
149 free_ipc_ns(ns);
150 }
151}
Eric W. Biedermana00eaf12010-03-07 18:48:39 -0800152
Al Viro3c041182014-11-01 00:25:30 -0400153static inline struct ipc_namespace *to_ipc_ns(struct ns_common *ns)
154{
155 return container_of(ns, struct ipc_namespace, ns);
156}
157
Al Viro64964522014-11-01 00:37:32 -0400158static struct ns_common *ipcns_get(struct task_struct *task)
Eric W. Biedermana00eaf12010-03-07 18:48:39 -0800159{
160 struct ipc_namespace *ns = NULL;
161 struct nsproxy *nsproxy;
162
Eric W. Biederman728dba32014-02-03 19:13:49 -0800163 task_lock(task);
164 nsproxy = task->nsproxy;
Eric W. Biedermana00eaf12010-03-07 18:48:39 -0800165 if (nsproxy)
166 ns = get_ipc_ns(nsproxy->ipc_ns);
Eric W. Biederman728dba32014-02-03 19:13:49 -0800167 task_unlock(task);
Eric W. Biedermana00eaf12010-03-07 18:48:39 -0800168
Al Viro3c041182014-11-01 00:25:30 -0400169 return ns ? &ns->ns : NULL;
Eric W. Biedermana00eaf12010-03-07 18:48:39 -0800170}
171
Al Viro64964522014-11-01 00:37:32 -0400172static void ipcns_put(struct ns_common *ns)
Eric W. Biedermana00eaf12010-03-07 18:48:39 -0800173{
Al Viro3c041182014-11-01 00:25:30 -0400174 return put_ipc_ns(to_ipc_ns(ns));
Eric W. Biedermana00eaf12010-03-07 18:48:39 -0800175}
176
Al Viro64964522014-11-01 00:37:32 -0400177static int ipcns_install(struct nsproxy *nsproxy, struct ns_common *new)
Eric W. Biedermana00eaf12010-03-07 18:48:39 -0800178{
Al Viro3c041182014-11-01 00:25:30 -0400179 struct ipc_namespace *ns = to_ipc_ns(new);
Eric W. Biederman5e4a0842012-12-14 07:55:36 -0800180 if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) ||
Eric W. Biedermanc7b96ac2013-03-20 12:49:49 -0700181 !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
Eric W. Biederman142e1d12012-07-26 01:13:20 -0700182 return -EPERM;
183
Eric W. Biedermana00eaf12010-03-07 18:48:39 -0800184 /* Ditch state from the old ipc namespace */
185 exit_sem(current);
186 put_ipc_ns(nsproxy->ipc_ns);
187 nsproxy->ipc_ns = get_ipc_ns(ns);
188 return 0;
189}
190
Andrey Vaginbcac25a2016-09-06 00:47:13 -0700191static struct user_namespace *ipcns_owner(struct ns_common *ns)
192{
193 return to_ipc_ns(ns)->user_ns;
194}
195
Eric W. Biedermana00eaf12010-03-07 18:48:39 -0800196const struct proc_ns_operations ipcns_operations = {
197 .name = "ipc",
198 .type = CLONE_NEWIPC,
199 .get = ipcns_get,
200 .put = ipcns_put,
201 .install = ipcns_install,
Andrey Vaginbcac25a2016-09-06 00:47:13 -0700202 .owner = ipcns_owner,
Eric W. Biedermana00eaf12010-03-07 18:48:39 -0800203};