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ae5e1b2 Pavel Emelyanov namespaces: move the IPC namespace under IPC_NS option
xemul authored
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>
7eafd7c namespaces: ipc namespaces: implement support for posix msqueues
Serge E. Hallyn authored
12 #include <linux/fs.h>
13 #include <linux/mount.h>
b515498 Serge Hallyn userns: add a user namespace owner of ipc ns
hallyn authored
14 #include <linux/user_namespace.h>
a00eaf1 ebiederm ns proc: Add support for the ipc namespace
ebiederm authored
15 #include <linux/proc_fs.h>
ae5e1b2 Pavel Emelyanov namespaces: move the IPC namespace under IPC_NS option
xemul authored
16
17 #include "util.h"
18
b0e7759 Serge Hallyn userns: user namespaces: convert several capable() calls
hallyn authored
19 static struct ipc_namespace *create_ipc_ns(struct task_struct *tsk,
20 struct ipc_namespace *old_ns)
ae5e1b2 Pavel Emelyanov namespaces: move the IPC namespace under IPC_NS option
xemul authored
21 {
22 struct ipc_namespace *ns;
7eafd7c namespaces: ipc namespaces: implement support for posix msqueues
Serge E. Hallyn authored
23 int err;
ae5e1b2 Pavel Emelyanov namespaces: move the IPC namespace under IPC_NS option
xemul authored
24
25 ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL);
26 if (ns == NULL)
ed2ddbf IPC: make struct ipc_ids static in ipc_namespace
Pierre Peiffer authored
27 return ERR_PTR(-ENOMEM);
ae5e1b2 Pavel Emelyanov namespaces: move the IPC namespace under IPC_NS option
xemul authored
28
7eafd7c namespaces: ipc namespaces: implement support for posix msqueues
Serge E. Hallyn authored
29 atomic_set(&ns->count, 1);
30 err = mq_init_ns(ns);
31 if (err) {
32 kfree(ns);
33 return ERR_PTR(err);
34 }
4d89dc6 ipc: scale msgmni to the number of ipc namespaces
Nadia Derbey authored
35 atomic_inc(&nr_ipc_ns);
36
ed2ddbf IPC: make struct ipc_ids static in ipc_namespace
Pierre Peiffer authored
37 sem_init_ns(ns);
38 msg_init_ns(ns);
39 shm_init_ns(ns);
ae5e1b2 Pavel Emelyanov namespaces: move the IPC namespace under IPC_NS option
xemul authored
40
e2c284d ipc: recompute msgmni on ipc namespace creation/removal
Nadia Derbey authored
41 /*
42 * msgmni has already been computed for the new ipc ns.
43 * Thus, do the ipcns creation notification before registering that
44 * new ipcns in the chain.
45 */
46 ipcns_notify(IPCNS_CREATED);
b6b337a ipc: recompute msgmni on memory add / remove
Nadia Derbey authored
47 register_ipcns_notifier(ns);
48
b0e7759 Serge Hallyn userns: user namespaces: convert several capable() calls
hallyn authored
49 ns->user_ns = get_user_ns(task_cred_xxx(tsk, user)->user_ns);
b515498 Serge Hallyn userns: add a user namespace owner of ipc ns
hallyn authored
50
ae5e1b2 Pavel Emelyanov namespaces: move the IPC namespace under IPC_NS option
xemul authored
51 return ns;
52 }
53
b0e7759 Serge Hallyn userns: user namespaces: convert several capable() calls
hallyn authored
54 struct ipc_namespace *copy_ipcs(unsigned long flags,
55 struct task_struct *tsk)
ae5e1b2 Pavel Emelyanov namespaces: move the IPC namespace under IPC_NS option
xemul authored
56 {
b0e7759 Serge Hallyn userns: user namespaces: convert several capable() calls
hallyn authored
57 struct ipc_namespace *ns = tsk->nsproxy->ipc_ns;
58
ae5e1b2 Pavel Emelyanov namespaces: move the IPC namespace under IPC_NS option
xemul authored
59 if (!(flags & CLONE_NEWIPC))
6442428 ipcns: remove useless get/put while CLONE_NEWIPC
Alexey Dobriyan authored
60 return get_ipc_ns(ns);
b0e7759 Serge Hallyn userns: user namespaces: convert several capable() calls
hallyn authored
61 return create_ipc_ns(tsk, ns);
ae5e1b2 Pavel Emelyanov namespaces: move the IPC namespace under IPC_NS option
xemul authored
62 }
63
01b8b07 IPC: consolidate sem_exit_ns(), msg_exit_ns() and shm_exit_ns()
Pierre Peiffer authored
64 /*
65 * free_ipcs - free all ipcs of one type
66 * @ns: the namespace to remove the ipcs from
67 * @ids: the table of ipcs to free
68 * @free: the function called to free each individual ipc
69 *
70 * Called for each kind of ipc when an ipc_namespace exits.
71 */
72 void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
73 void (*free)(struct ipc_namespace *, struct kern_ipc_perm *))
74 {
75 struct kern_ipc_perm *perm;
76 int next_id;
77 int total, in_use;
78
79 down_write(&ids->rw_mutex);
80
81 in_use = ids->in_use;
82
83 for (total = 0, next_id = 0; total < in_use; next_id++) {
84 perm = idr_find(&ids->ipcs_idr, next_id);
85 if (perm == NULL)
86 continue;
87 ipc_lock_by_ptr(perm);
88 free(ns, perm);
89 total++;
90 }
91 up_write(&ids->rw_mutex);
92 }
93
b4188de ipcns: make free_ipc_ns() static
Alexey Dobriyan authored
94 static void free_ipc_ns(struct ipc_namespace *ns)
95 {
96 /*
97 * Unregistering the hotplug notifier at the beginning guarantees
98 * that the ipc namespace won't be freed while we are inside the
99 * callback routine. Since the blocking_notifier_chain_XXX routines
100 * hold a rw lock on the notifier list, unregister_ipcns_notifier()
101 * won't take the rw lock before blocking_notifier_call_chain() has
102 * released the rd lock.
103 */
104 unregister_ipcns_notifier(ns);
105 sem_exit_ns(ns);
106 msg_exit_ns(ns);
107 shm_exit_ns(ns);
108 atomic_dec(&nr_ipc_ns);
109
110 /*
111 * Do the ipcns removal notification after decrementing nr_ipc_ns in
112 * order to have a correct value when recomputing msgmni.
113 */
114 ipcns_notify(IPCNS_REMOVED);
b515498 Serge Hallyn userns: add a user namespace owner of ipc ns
hallyn authored
115 put_user_ns(ns->user_ns);
be4d250 ipcns: fix use after free in free_ipc_ns()
Xiaotian Feng authored
116 kfree(ns);
b4188de ipcns: make free_ipc_ns() static
Alexey Dobriyan authored
117 }
118
7eafd7c namespaces: ipc namespaces: implement support for posix msqueues
Serge E. Hallyn authored
119 /*
120 * put_ipc_ns - drop a reference to an ipc namespace.
121 * @ns: the namespace to put
122 *
123 * If this is the last task in the namespace exiting, and
124 * it is dropping the refcount to 0, then it can race with
125 * a task in another ipc namespace but in a mounts namespace
126 * which has this ipcns's mqueuefs mounted, doing some action
127 * with one of the mqueuefs files. That can raise the refcount.
128 * So dropping the refcount, and raising the refcount when
129 * accessing it through the VFS, are protected with mq_lock.
130 *
131 * (Clearly, a task raising the refcount on its own ipc_ns
132 * needn't take mq_lock since it can't race with the last task
133 * in the ipcns exiting).
134 */
135 void put_ipc_ns(struct ipc_namespace *ns)
ae5e1b2 Pavel Emelyanov namespaces: move the IPC namespace under IPC_NS option
xemul authored
136 {
7eafd7c namespaces: ipc namespaces: implement support for posix msqueues
Serge E. Hallyn authored
137 if (atomic_dec_and_lock(&ns->count, &mq_lock)) {
138 mq_clear_sbinfo(ns);
139 spin_unlock(&mq_lock);
140 mq_put_mnt(ns);
141 free_ipc_ns(ns);
142 }
143 }
a00eaf1 ebiederm ns proc: Add support for the ipc namespace
ebiederm authored
144
145 static void *ipcns_get(struct task_struct *task)
146 {
147 struct ipc_namespace *ns = NULL;
148 struct nsproxy *nsproxy;
149
150 rcu_read_lock();
151 nsproxy = task_nsproxy(task);
152 if (nsproxy)
153 ns = get_ipc_ns(nsproxy->ipc_ns);
154 rcu_read_unlock();
155
156 return ns;
157 }
158
159 static void ipcns_put(void *ns)
160 {
161 return put_ipc_ns(ns);
162 }
163
164 static int ipcns_install(struct nsproxy *nsproxy, void *ns)
165 {
166 /* Ditch state from the old ipc namespace */
167 exit_sem(current);
168 put_ipc_ns(nsproxy->ipc_ns);
169 nsproxy->ipc_ns = get_ipc_ns(ns);
170 return 0;
171 }
172
173 const struct proc_ns_operations ipcns_operations = {
174 .name = "ipc",
175 .type = CLONE_NEWIPC,
176 .get = ipcns_get,
177 .put = ipcns_put,
178 .install = ipcns_install,
179 };
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