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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>
12#include <linux/fs.h>
13#include <linux/mount.h>
14#include <linux/user_namespace.h>
15#include <linux/proc_ns.h>
16
17#include "util.h"
18
19static 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
29static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns,
30 struct ipc_namespace *old_ns)
31{
32 struct ipc_namespace *ns;
33 struct ucounts *ucounts;
34 int err;
35
36 err = -ENOSPC;
37 ucounts = inc_ipc_namespaces(user_ns);
38 if (!ucounts)
39 goto fail;
40
41 err = -ENOMEM;
42 ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL);
43 if (ns == NULL)
44 goto fail_dec;
45
46 err = ns_alloc_inum(&ns->ns);
47 if (err)
48 goto fail_free;
49 ns->ns.ops = &ipcns_operations;
50
51 atomic_set(&ns->count, 1);
52 ns->user_ns = get_user_ns(user_ns);
53 ns->ucounts = ucounts;
54
55 err = mq_init_ns(ns);
56 if (err)
57 goto fail_put;
58
59 sem_init_ns(ns);
60 msg_init_ns(ns);
61 shm_init_ns(ns);
62
63 return ns;
64
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);
74}
75
76struct ipc_namespace *copy_ipcs(unsigned long flags,
77 struct user_namespace *user_ns, struct ipc_namespace *ns)
78{
79 if (!(flags & CLONE_NEWIPC))
80 return get_ipc_ns(ns);
81 return create_ipc_ns(user_ns, ns);
82}
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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
99 down_write(&ids->rwsem);
100
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;
107 rcu_read_lock();
108 ipc_lock_object(perm);
109 free(ns, perm);
110 total++;
111 }
112 up_write(&ids->rwsem);
113}
114
115static void free_ipc_ns(struct ipc_namespace *ns)
116{
117 sem_exit_ns(ns);
118 msg_exit_ns(ns);
119 shm_exit_ns(ns);
120
121 dec_ipc_namespaces(ns->ucounts);
122 put_user_ns(ns->user_ns);
123 ns_free_inum(&ns->ns);
124 kfree(ns);
125}
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142
143void put_ipc_ns(struct ipc_namespace *ns)
144{
145 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}
152
153static inline struct ipc_namespace *to_ipc_ns(struct ns_common *ns)
154{
155 return container_of(ns, struct ipc_namespace, ns);
156}
157
158static struct ns_common *ipcns_get(struct task_struct *task)
159{
160 struct ipc_namespace *ns = NULL;
161 struct nsproxy *nsproxy;
162
163 task_lock(task);
164 nsproxy = task->nsproxy;
165 if (nsproxy)
166 ns = get_ipc_ns(nsproxy->ipc_ns);
167 task_unlock(task);
168
169 return ns ? &ns->ns : NULL;
170}
171
172static void ipcns_put(struct ns_common *ns)
173{
174 return put_ipc_ns(to_ipc_ns(ns));
175}
176
177static int ipcns_install(struct nsproxy *nsproxy, struct ns_common *new)
178{
179 struct ipc_namespace *ns = to_ipc_ns(new);
180 if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) ||
181 !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
182 return -EPERM;
183
184
185 exit_sem(current);
186 put_ipc_ns(nsproxy->ipc_ns);
187 nsproxy->ipc_ns = get_ipc_ns(ns);
188 return 0;
189}
190
191static struct user_namespace *ipcns_owner(struct ns_common *ns)
192{
193 return to_ipc_ns(ns)->user_ns;
194}
195
196const 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,
202 .owner = ipcns_owner,
203};
204