ipc_sysctl.c revision 99db46ea
1/*
2 *  Copyright (C) 2007
3 *
4 *  Author: Eric Biederman <ebiederm@xmision.com>
5 *
6 *  This program is free software; you can redistribute it and/or
7 *  modify it under the terms of the GNU General Public License as
8 *  published by the Free Software Foundation, version 2 of the
9 *  License.
10 */
11
12#include <linux/module.h>
13#include <linux/ipc.h>
14#include <linux/nsproxy.h>
15#include <linux/sysctl.h>
16#include <linux/uaccess.h>
17#include <linux/ipc_namespace.h>
18#include <linux/msg.h>
19#include "util.h"
20
21static void *get_ipc(struct ctl_table *table)
22{
23	char *which = table->data;
24	struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
25	which = (which - (char *)&init_ipc_ns) + (char *)ipc_ns;
26	return which;
27}
28
29#ifdef CONFIG_PROC_SYSCTL
30static int proc_ipc_dointvec(struct ctl_table *table, int write,
31	void __user *buffer, size_t *lenp, loff_t *ppos)
32{
33	struct ctl_table ipc_table;
34
35	memcpy(&ipc_table, table, sizeof(ipc_table));
36	ipc_table.data = get_ipc(table);
37
38	return proc_dointvec(&ipc_table, write, buffer, lenp, ppos);
39}
40
41static int proc_ipc_dointvec_minmax(struct ctl_table *table, int write,
42	void __user *buffer, size_t *lenp, loff_t *ppos)
43{
44	struct ctl_table ipc_table;
45
46	memcpy(&ipc_table, table, sizeof(ipc_table));
47	ipc_table.data = get_ipc(table);
48
49	return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
50}
51
52static int proc_ipc_dointvec_minmax_orphans(struct ctl_table *table, int write,
53	void __user *buffer, size_t *lenp, loff_t *ppos)
54{
55	struct ipc_namespace *ns = current->nsproxy->ipc_ns;
56	int err = proc_ipc_dointvec_minmax(table, write, buffer, lenp, ppos);
57
58	if (err < 0)
59		return err;
60	if (ns->shm_rmid_forced)
61		shm_destroy_orphaned(ns);
62	return err;
63}
64
65static int proc_ipc_doulongvec_minmax(struct ctl_table *table, int write,
66	void __user *buffer, size_t *lenp, loff_t *ppos)
67{
68	struct ctl_table ipc_table;
69	memcpy(&ipc_table, table, sizeof(ipc_table));
70	ipc_table.data = get_ipc(table);
71
72	return proc_doulongvec_minmax(&ipc_table, write, buffer,
73					lenp, ppos);
74}
75
76static int proc_ipc_auto_msgmni(struct ctl_table *table, int write,
77	void __user *buffer, size_t *lenp, loff_t *ppos)
78{
79	struct ctl_table ipc_table;
80	int dummy = 0;
81
82	memcpy(&ipc_table, table, sizeof(ipc_table));
83	ipc_table.data = &dummy;
84
85	if (write)
86		pr_info_once("writing to auto_msgmni has no effect");
87
88	return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
89}
90
91static int proc_ipc_sem_dointvec(struct ctl_table *table, int write,
92	void __user *buffer, size_t *lenp, loff_t *ppos)
93{
94	int ret, semmni;
95	struct ipc_namespace *ns = current->nsproxy->ipc_ns;
96
97	semmni = ns->sem_ctls[3];
98	ret = proc_ipc_dointvec(table, write, buffer, lenp, ppos);
99
100	if (!ret)
101		ret = sem_check_semmni(current->nsproxy->ipc_ns);
102
103	/*
104	 * Reset the semmni value if an error happens.
105	 */
106	if (ret)
107		ns->sem_ctls[3] = semmni;
108	return ret;
109}
110
111#else
112#define proc_ipc_doulongvec_minmax NULL
113#define proc_ipc_dointvec	   NULL
114#define proc_ipc_dointvec_minmax   NULL
115#define proc_ipc_dointvec_minmax_orphans   NULL
116#define proc_ipc_auto_msgmni	   NULL
117#define proc_ipc_sem_dointvec	   NULL
118#endif
119
120static int zero;
121static int one = 1;
122static int int_max = INT_MAX;
123int ipc_mni = IPCMNI;
124int ipc_mni_shift = IPCMNI_SHIFT;
125int ipc_min_cycle = RADIX_TREE_MAP_SIZE;
126
127static struct ctl_table ipc_kern_table[] = {
128	{
129		.procname	= "shmmax",
130		.data		= &init_ipc_ns.shm_ctlmax,
131		.maxlen		= sizeof(init_ipc_ns.shm_ctlmax),
132		.mode		= 0644,
133		.proc_handler	= proc_ipc_doulongvec_minmax,
134	},
135	{
136		.procname	= "shmall",
137		.data		= &init_ipc_ns.shm_ctlall,
138		.maxlen		= sizeof(init_ipc_ns.shm_ctlall),
139		.mode		= 0644,
140		.proc_handler	= proc_ipc_doulongvec_minmax,
141	},
142	{
143		.procname	= "shmmni",
144		.data		= &init_ipc_ns.shm_ctlmni,
145		.maxlen		= sizeof(init_ipc_ns.shm_ctlmni),
146		.mode		= 0644,
147		.proc_handler	= proc_ipc_dointvec_minmax,
148		.extra1		= &zero,
149		.extra2		= &ipc_mni,
150	},
151	{
152		.procname	= "shm_rmid_forced",
153		.data		= &init_ipc_ns.shm_rmid_forced,
154		.maxlen		= sizeof(init_ipc_ns.shm_rmid_forced),
155		.mode		= 0644,
156		.proc_handler	= proc_ipc_dointvec_minmax_orphans,
157		.extra1		= &zero,
158		.extra2		= &one,
159	},
160	{
161		.procname	= "msgmax",
162		.data		= &init_ipc_ns.msg_ctlmax,
163		.maxlen		= sizeof(init_ipc_ns.msg_ctlmax),
164		.mode		= 0644,
165		.proc_handler	= proc_ipc_dointvec_minmax,
166		.extra1		= &zero,
167		.extra2		= &int_max,
168	},
169	{
170		.procname	= "msgmni",
171		.data		= &init_ipc_ns.msg_ctlmni,
172		.maxlen		= sizeof(init_ipc_ns.msg_ctlmni),
173		.mode		= 0644,
174		.proc_handler	= proc_ipc_dointvec_minmax,
175		.extra1		= &zero,
176		.extra2		= &ipc_mni,
177	},
178	{
179		.procname	= "auto_msgmni",
180		.data		= NULL,
181		.maxlen		= sizeof(int),
182		.mode		= 0644,
183		.proc_handler	= proc_ipc_auto_msgmni,
184		.extra1		= &zero,
185		.extra2		= &one,
186	},
187	{
188		.procname	=  "msgmnb",
189		.data		= &init_ipc_ns.msg_ctlmnb,
190		.maxlen		= sizeof(init_ipc_ns.msg_ctlmnb),
191		.mode		= 0644,
192		.proc_handler	= proc_ipc_dointvec_minmax,
193		.extra1		= &zero,
194		.extra2		= &int_max,
195	},
196	{
197		.procname	= "sem",
198		.data		= &init_ipc_ns.sem_ctls,
199		.maxlen		= 4*sizeof(int),
200		.mode		= 0644,
201		.proc_handler	= proc_ipc_sem_dointvec,
202	},
203#ifdef CONFIG_CHECKPOINT_RESTORE
204	{
205		.procname	= "sem_next_id",
206		.data		= &init_ipc_ns.ids[IPC_SEM_IDS].next_id,
207		.maxlen		= sizeof(init_ipc_ns.ids[IPC_SEM_IDS].next_id),
208		.mode		= 0644,
209		.proc_handler	= proc_ipc_dointvec_minmax,
210		.extra1		= &zero,
211		.extra2		= &int_max,
212	},
213	{
214		.procname	= "msg_next_id",
215		.data		= &init_ipc_ns.ids[IPC_MSG_IDS].next_id,
216		.maxlen		= sizeof(init_ipc_ns.ids[IPC_MSG_IDS].next_id),
217		.mode		= 0644,
218		.proc_handler	= proc_ipc_dointvec_minmax,
219		.extra1		= &zero,
220		.extra2		= &int_max,
221	},
222	{
223		.procname	= "shm_next_id",
224		.data		= &init_ipc_ns.ids[IPC_SHM_IDS].next_id,
225		.maxlen		= sizeof(init_ipc_ns.ids[IPC_SHM_IDS].next_id),
226		.mode		= 0644,
227		.proc_handler	= proc_ipc_dointvec_minmax,
228		.extra1		= &zero,
229		.extra2		= &int_max,
230	},
231#endif
232	{}
233};
234
235static struct ctl_table ipc_root_table[] = {
236	{
237		.procname	= "kernel",
238		.mode		= 0555,
239		.child		= ipc_kern_table,
240	},
241	{}
242};
243
244static int __init ipc_sysctl_init(void)
245{
246	register_sysctl_table(ipc_root_table);
247	return 0;
248}
249
250device_initcall(ipc_sysctl_init);
251
252static int __init ipc_mni_extend(char *str)
253{
254	ipc_mni = IPCMNI_EXTEND;
255	ipc_mni_shift = IPCMNI_EXTEND_SHIFT;
256	ipc_min_cycle = IPCMNI_EXTEND_MIN_CYCLE;
257	pr_info("IPCMNI extended to %d.\n", ipc_mni);
258	return 0;
259}
260early_param("ipcmni_extend", ipc_mni_extend);
261