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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>
13#include <linux/cred.h>
14#include <linux/fs.h>
15#include <linux/mount.h>
16#include <linux/user_namespace.h>
17#include <linux/proc_ns.h>
18#include <linux/sched/task.h>
19
20#include "util.h"
21
22static struct ucounts *inc_ipc_namespaces(struct user_namespace *ns)
23{
24 return inc_ucount(ns, current_euid(), UCOUNT_IPC_NAMESPACES);
25}
26
27static void dec_ipc_namespaces(struct ucounts *ucounts)
28{
29 dec_ucount(ucounts, UCOUNT_IPC_NAMESPACES);
30}
31
32static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns,
33 struct ipc_namespace *old_ns)
34{
35 struct ipc_namespace *ns;
36 struct ucounts *ucounts;
37 int err;
38
39 err = -ENOSPC;
40 ucounts = inc_ipc_namespaces(user_ns);
41 if (!ucounts)
42 goto fail;
43
44 err = -ENOMEM;
45 ns = kzalloc(sizeof(struct ipc_namespace), GFP_KERNEL_ACCOUNT);
46 if (ns == NULL)
47 goto fail_dec;
48
49 err = ns_alloc_inum(&ns->ns);
50 if (err)
51 goto fail_free;
52 ns->ns.ops = &ipcns_operations;
53
54 refcount_set(&ns->ns.count, 1);
55 ns->user_ns = get_user_ns(user_ns);
56 ns->ucounts = ucounts;
57
58 err = mq_init_ns(ns);
59 if (err)
60 goto fail_put;
61
62 sem_init_ns(ns);
63 msg_init_ns(ns);
64 shm_init_ns(ns);
65
66 return ns;
67
68fail_put:
69 put_user_ns(ns->user_ns);
70 ns_free_inum(&ns->ns);
71fail_free:
72 kfree(ns);
73fail_dec:
74 dec_ipc_namespaces(ucounts);
75fail:
76 return ERR_PTR(err);
77}
78
79struct ipc_namespace *copy_ipcs(unsigned long flags,
80 struct user_namespace *user_ns, struct ipc_namespace *ns)
81{
82 if (!(flags & CLONE_NEWIPC))
83 return get_ipc_ns(ns);
84 return create_ipc_ns(user_ns, ns);
85}
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94
95void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
96 void (*free)(struct ipc_namespace *, struct kern_ipc_perm *))
97{
98 struct kern_ipc_perm *perm;
99 int next_id;
100 int total, in_use;
101
102 down_write(&ids->rwsem);
103
104 in_use = ids->in_use;
105
106 for (total = 0, next_id = 0; total < in_use; next_id++) {
107 perm = idr_find(&ids->ipcs_idr, next_id);
108 if (perm == NULL)
109 continue;
110 rcu_read_lock();
111 ipc_lock_object(perm);
112 free(ns, perm);
113 total++;
114 }
115 up_write(&ids->rwsem);
116}
117
118static void free_ipc_ns(struct ipc_namespace *ns)
119{
120
121
122
123 mq_put_mnt(ns);
124 sem_exit_ns(ns);
125 msg_exit_ns(ns);
126 shm_exit_ns(ns);
127
128 dec_ipc_namespaces(ns->ucounts);
129 put_user_ns(ns->user_ns);
130 ns_free_inum(&ns->ns);
131 kfree(ns);
132}
133
134static LLIST_HEAD(free_ipc_list);
135static void free_ipc(struct work_struct *unused)
136{
137 struct llist_node *node = llist_del_all(&free_ipc_list);
138 struct ipc_namespace *n, *t;
139
140 llist_for_each_entry_safe(n, t, node, mnt_llist)
141 free_ipc_ns(n);
142}
143
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146
147static DECLARE_WORK(free_ipc_work, free_ipc);
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164
165void put_ipc_ns(struct ipc_namespace *ns)
166{
167 if (refcount_dec_and_lock(&ns->ns.count, &mq_lock)) {
168 mq_clear_sbinfo(ns);
169 spin_unlock(&mq_lock);
170
171 if (llist_add(&ns->mnt_llist, &free_ipc_list))
172 schedule_work(&free_ipc_work);
173 }
174}
175
176static inline struct ipc_namespace *to_ipc_ns(struct ns_common *ns)
177{
178 return container_of(ns, struct ipc_namespace, ns);
179}
180
181static struct ns_common *ipcns_get(struct task_struct *task)
182{
183 struct ipc_namespace *ns = NULL;
184 struct nsproxy *nsproxy;
185
186 task_lock(task);
187 nsproxy = task->nsproxy;
188 if (nsproxy)
189 ns = get_ipc_ns(nsproxy->ipc_ns);
190 task_unlock(task);
191
192 return ns ? &ns->ns : NULL;
193}
194
195static void ipcns_put(struct ns_common *ns)
196{
197 return put_ipc_ns(to_ipc_ns(ns));
198}
199
200static int ipcns_install(struct nsset *nsset, struct ns_common *new)
201{
202 struct nsproxy *nsproxy = nsset->nsproxy;
203 struct ipc_namespace *ns = to_ipc_ns(new);
204 if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) ||
205 !ns_capable(nsset->cred->user_ns, CAP_SYS_ADMIN))
206 return -EPERM;
207
208 put_ipc_ns(nsproxy->ipc_ns);
209 nsproxy->ipc_ns = get_ipc_ns(ns);
210 return 0;
211}
212
213static struct user_namespace *ipcns_owner(struct ns_common *ns)
214{
215 return to_ipc_ns(ns)->user_ns;
216}
217
218const struct proc_ns_operations ipcns_operations = {
219 .name = "ipc",
220 .type = CLONE_NEWIPC,
221 .get = ipcns_get,
222 .put = ipcns_put,
223 .install = ipcns_install,
224 .owner = ipcns_owner,
225};
226