aboutsummaryrefslogtreecommitdiffstats
path: root/ipc/ipc_sysctl.c
blob: ef313ecfb53a12e4f63be71d5b3f6a05afcb79de (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
// SPDX-License-Identifier: GPL-2.0-only
/*
 *  Copyright (C) 2007
 *
 *  Author: Eric Biederman <ebiederm@xmision.com>
 */

#include <linux/module.h>
#include <linux/ipc.h>
#include <linux/nsproxy.h>
#include <linux/sysctl.h>
#include <linux/uaccess.h>
#include <linux/capability.h>
#include <linux/ipc_namespace.h>
#include <linux/msg.h>
#include <linux/slab.h>
#include "util.h"

static int proc_ipc_dointvec_minmax_orphans(struct ctl_table *table, int write,
		void *buffer, size_t *lenp, loff_t *ppos)
{
	struct ipc_namespace *ns =
		container_of(table->data, struct ipc_namespace, shm_rmid_forced);
	int err;

	err = proc_dointvec_minmax(table, write, buffer, lenp, ppos);

	if (err < 0)
		return err;
	if (ns->shm_rmid_forced)
		shm_destroy_orphaned(ns);
	return err;
}

static int proc_ipc_auto_msgmni(struct ctl_table *table, int write,
		void *buffer, size_t *lenp, loff_t *ppos)
{
	struct ctl_table ipc_table;
	int dummy = 0;

	memcpy(&ipc_table, table, sizeof(ipc_table));
	ipc_table.data = &dummy;

	if (write)
		pr_info_once("writing to auto_msgmni has no effect");

	return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
}

static int proc_ipc_sem_dointvec(struct ctl_table *table, int write,
	void *buffer, size_t *lenp, loff_t *ppos)
{
	struct ipc_namespace *ns =
		container_of(table->data, struct ipc_namespace, sem_ctls);
	int ret, semmni;

	semmni = ns->sem_ctls[3];
	ret = proc_dointvec(table, write, buffer, lenp, ppos);

	if (!ret)
		ret = sem_check_semmni(ns);

	/*
	 * Reset the semmni value if an error happens.
	 */
	if (ret)
		ns->sem_ctls[3] = semmni;
	return ret;
}

int ipc_mni = IPCMNI;
int ipc_mni_shift = IPCMNI_SHIFT;
int ipc_min_cycle = RADIX_TREE_MAP_SIZE;

static struct ctl_table ipc_sysctls[] = {
	{
		.procname	= "shmmax",
		.data		= &init_ipc_ns.shm_ctlmax,
		.maxlen		= sizeof(init_ipc_ns.shm_ctlmax),
		.mode		= 0644,
		.proc_handler	= proc_doulongvec_minmax,
	},
	{
		.procname	= "shmall",
		.data		= &init_ipc_ns.shm_ctlall,
		.maxlen		= sizeof(init_ipc_ns.shm_ctlall),
		.mode		= 0644,
		.proc_handler	= proc_doulongvec_minmax,
	},
	{
		.procname	= "shmmni",
		.data		= &init_ipc_ns.shm_ctlmni,
		.maxlen		= sizeof(init_ipc_ns.shm_ctlmni),
		.mode		= 0644,
		.proc_handler	= proc_dointvec_minmax,
		.extra1		= SYSCTL_ZERO,
		.extra2		= &ipc_mni,
	},
	{
		.procname	= "shm_rmid_forced",
		.data		= &init_ipc_ns.shm_rmid_forced,
		.maxlen		= sizeof(init_ipc_ns.shm_rmid_forced),
		.mode		= 0644,
		.proc_handler	= proc_ipc_dointvec_minmax_orphans,
		.extra1		= SYSCTL_ZERO,
		.extra2		= SYSCTL_ONE,
	},
	{
		.procname	= "msgmax",
		.data		= &init_ipc_ns.msg_ctlmax,
		.maxlen		= sizeof(init_ipc_ns.msg_ctlmax),
		.mode		= 0644,
		.proc_handler	= proc_dointvec_minmax,
		.extra1		= SYSCTL_ZERO,
		.extra2		= SYSCTL_INT_MAX,
	},
	{
		.procname	= "msgmni",
		.data		= &init_ipc_ns.msg_ctlmni,
		.maxlen		= sizeof(init_ipc_ns.msg_ctlmni),
		.mode		= 0644,
		.proc_handler	= proc_dointvec_minmax,
		.extra1		= SYSCTL_ZERO,
		.extra2		= &ipc_mni,
	},
	{
		.procname	= "auto_msgmni",
		.data		= NULL,
		.maxlen		= sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_ipc_auto_msgmni,
		.extra1		= SYSCTL_ZERO,
		.extra2		= SYSCTL_ONE,
	},
	{
		.procname	=  "msgmnb",
		.data		= &init_ipc_ns.msg_ctlmnb,
		.maxlen		= sizeof(init_ipc_ns.msg_ctlmnb),
		.mode		= 0644,
		.proc_handler	= proc_dointvec_minmax,
		.extra1		= SYSCTL_ZERO,
		.extra2		= SYSCTL_INT_MAX,
	},
	{
		.procname	= "sem",
		.data		= &init_ipc_ns.sem_ctls,
		.maxlen		= 4*sizeof(int),
		.mode		= 0644,
		.proc_handler	= proc_ipc_sem_dointvec,
	},
#ifdef CONFIG_CHECKPOINT_RESTORE
	{
		.procname	= "sem_next_id",
		.data		= &init_ipc_ns.ids[IPC_SEM_IDS].next_id,
		.maxlen		= sizeof(init_ipc_ns.ids[IPC_SEM_IDS].next_id),
		.mode		= 0444,
		.proc_handler	= proc_dointvec_minmax,
		.extra1		= SYSCTL_ZERO,
		.extra2		= SYSCTL_INT_MAX,
	},
	{
		.procname	= "msg_next_id",
		.data		= &init_ipc_ns.ids[IPC_MSG_IDS].next_id,
		.maxlen		= sizeof(init_ipc_ns.ids[IPC_MSG_IDS].next_id),
		.mode		= 0444,
		.proc_handler	= proc_dointvec_minmax,
		.extra1		= SYSCTL_ZERO,
		.extra2		= SYSCTL_INT_MAX,
	},
	{
		.procname	= "shm_next_id",
		.data		= &init_ipc_ns.ids[IPC_SHM_IDS].next_id,
		.maxlen		= sizeof(init_ipc_ns.ids[IPC_SHM_IDS].next_id),
		.mode		= 0444,
		.proc_handler	= proc_dointvec_minmax,
		.extra1		= SYSCTL_ZERO,
		.extra2		= SYSCTL_INT_MAX,
	},
#endif
	{}
};

static struct ctl_table_set *set_lookup(struct ctl_table_root *root)
{
	return &current->nsproxy->ipc_ns->ipc_set;
}

static int set_is_seen(struct ctl_table_set *set)
{
	return &current->nsproxy->ipc_ns->ipc_set == set;
}

static int ipc_permissions(struct ctl_table_header *head, struct ctl_table *table)
{
	int mode = table->mode;

#ifdef CONFIG_CHECKPOINT_RESTORE
	struct ipc_namespace *ns = current->nsproxy->ipc_ns;

	if (((table->data == &ns->ids[IPC_SEM_IDS].next_id) ||
	     (table->data == &ns->ids[IPC_MSG_IDS].next_id) ||
	     (table->data == &ns->ids[IPC_SHM_IDS].next_id)) &&
	    checkpoint_restore_ns_capable(ns->user_ns))
		mode = 0666;
#endif
	return mode;
}

static struct ctl_table_root set_root = {
	.lookup = set_lookup,
	.permissions = ipc_permissions,
};

bool setup_ipc_sysctls(struct ipc_namespace *ns)
{
	struct ctl_table *tbl;

	setup_sysctl_set(&ns->ipc_set, &set_root, set_is_seen);

	tbl = kmemdup(ipc_sysctls, sizeof(ipc_sysctls), GFP_KERNEL);
	if (tbl) {
		int i;

		for (i = 0; i < ARRAY_SIZE(ipc_sysctls); i++) {
			if (tbl[i].data == &init_ipc_ns.shm_ctlmax)
				tbl[i].data = &ns->shm_ctlmax;

			else if (tbl[i].data == &init_ipc_ns.shm_ctlall)
				tbl[i].data = &ns->shm_ctlall;

			else if (tbl[i].data == &init_ipc_ns.shm_ctlmni)
				tbl[i].data = &ns->shm_ctlmni;

			else if (tbl[i].data == &init_ipc_ns.shm_rmid_forced)
				tbl[i].data = &ns->shm_rmid_forced;

			else if (tbl[i].data == &init_ipc_ns.msg_ctlmax)
				tbl[i].data = &ns->msg_ctlmax;

			else if (tbl[i].data == &init_ipc_ns.msg_ctlmni)
				tbl[i].data = &ns->msg_ctlmni;

			else if (tbl[i].data == &init_ipc_ns.msg_ctlmnb)
				tbl[i].data = &ns->msg_ctlmnb;

			else if (tbl[i].data == &init_ipc_ns.sem_ctls)
				tbl[i].data = &ns->sem_ctls;
#ifdef CONFIG_CHECKPOINT_RESTORE
			else if (tbl[i].data == &init_ipc_ns.ids[IPC_SEM_IDS].next_id)
				tbl[i].data = &ns->ids[IPC_SEM_IDS].next_id;

			else if (tbl[i].data == &init_ipc_ns.ids[IPC_MSG_IDS].next_id)
				tbl[i].data = &ns->ids[IPC_MSG_IDS].next_id;

			else if (tbl[i].data == &init_ipc_ns.ids[IPC_SHM_IDS].next_id)
				tbl[i].data = &ns->ids[IPC_SHM_IDS].next_id;
#endif
			else
				tbl[i].data = NULL;
		}

		ns->ipc_sysctls = __register_sysctl_table(&ns->ipc_set, "kernel", tbl);
	}
	if (!ns->ipc_sysctls) {
		kfree(tbl);
		retire_sysctl_set(&ns->ipc_set);
		return false;
	}

	return true;
}

void retire_ipc_sysctls(struct ipc_namespace *ns)
{
	struct ctl_table *tbl;

	tbl = ns->ipc_sysctls->ctl_table_arg;
	unregister_sysctl_table(ns->ipc_sysctls);
	retire_sysctl_set(&ns->ipc_set);
	kfree(tbl);
}

static int __init ipc_sysctl_init(void)
{
	if (!setup_ipc_sysctls(&init_ipc_ns)) {
		pr_warn("ipc sysctl registration failed\n");
		return -ENOMEM;
	}
	return 0;
}

device_initcall(ipc_sysctl_init);

static int __init ipc_mni_extend(char *str)
{
	ipc_mni = IPCMNI_EXTEND;
	ipc_mni_shift = IPCMNI_EXTEND_SHIFT;
	ipc_min_cycle = IPCMNI_EXTEND_MIN_CYCLE;
	pr_info("IPCMNI extended to %d.\n", ipc_mni);
	return 0;
}
early_param("ipcmni_extend", ipc_mni_extend);