ipc_sysctl.c revision 32927393
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 *  Copyright (C) 2007
4 *
5 *  Author: Eric Biederman <ebiederm@xmision.com>
6 */
7
8#include <linux/module.h>
9#include <linux/ipc.h>
10#include <linux/nsproxy.h>
11#include <linux/sysctl.h>
12#include <linux/uaccess.h>
13#include <linux/ipc_namespace.h>
14#include <linux/msg.h>
15#include "util.h"
16
17static void *get_ipc(struct ctl_table *table)
18{
19	char *which = table->data;
20	struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
21	which = (which - (char *)&init_ipc_ns) + (char *)ipc_ns;
22	return which;
23}
24
25#ifdef CONFIG_PROC_SYSCTL
26static int proc_ipc_dointvec(struct ctl_table *table, int write,
27		void *buffer, size_t *lenp, loff_t *ppos)
28{
29	struct ctl_table ipc_table;
30
31	memcpy(&ipc_table, table, sizeof(ipc_table));
32	ipc_table.data = get_ipc(table);
33
34	return proc_dointvec(&ipc_table, write, buffer, lenp, ppos);
35}
36
37static int proc_ipc_dointvec_minmax(struct ctl_table *table, int write,
38		void *buffer, size_t *lenp, loff_t *ppos)
39{
40	struct ctl_table ipc_table;
41
42	memcpy(&ipc_table, table, sizeof(ipc_table));
43	ipc_table.data = get_ipc(table);
44
45	return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
46}
47
48static int proc_ipc_dointvec_minmax_orphans(struct ctl_table *table, int write,
49		void *buffer, size_t *lenp, loff_t *ppos)
50{
51	struct ipc_namespace *ns = current->nsproxy->ipc_ns;
52	int err = proc_ipc_dointvec_minmax(table, write, buffer, lenp, ppos);
53
54	if (err < 0)
55		return err;
56	if (ns->shm_rmid_forced)
57		shm_destroy_orphaned(ns);
58	return err;
59}
60
61static int proc_ipc_doulongvec_minmax(struct ctl_table *table, int write,
62		void *buffer, size_t *lenp, loff_t *ppos)
63{
64	struct ctl_table ipc_table;
65	memcpy(&ipc_table, table, sizeof(ipc_table));
66	ipc_table.data = get_ipc(table);
67
68	return proc_doulongvec_minmax(&ipc_table, write, buffer,
69					lenp, ppos);
70}
71
72static int proc_ipc_auto_msgmni(struct ctl_table *table, int write,
73		void *buffer, size_t *lenp, loff_t *ppos)
74{
75	struct ctl_table ipc_table;
76	int dummy = 0;
77
78	memcpy(&ipc_table, table, sizeof(ipc_table));
79	ipc_table.data = &dummy;
80
81	if (write)
82		pr_info_once("writing to auto_msgmni has no effect");
83
84	return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
85}
86
87static int proc_ipc_sem_dointvec(struct ctl_table *table, int write,
88	void __user *buffer, size_t *lenp, loff_t *ppos)
89{
90	int ret, semmni;
91	struct ipc_namespace *ns = current->nsproxy->ipc_ns;
92
93	semmni = ns->sem_ctls[3];
94	ret = proc_ipc_dointvec(table, write, buffer, lenp, ppos);
95
96	if (!ret)
97		ret = sem_check_semmni(current->nsproxy->ipc_ns);
98
99	/*
100	 * Reset the semmni value if an error happens.
101	 */
102	if (ret)
103		ns->sem_ctls[3] = semmni;
104	return ret;
105}
106
107#else
108#define proc_ipc_doulongvec_minmax NULL
109#define proc_ipc_dointvec	   NULL
110#define proc_ipc_dointvec_minmax   NULL
111#define proc_ipc_dointvec_minmax_orphans   NULL
112#define proc_ipc_auto_msgmni	   NULL
113#define proc_ipc_sem_dointvec	   NULL
114#endif
115
116int ipc_mni = IPCMNI;
117int ipc_mni_shift = IPCMNI_SHIFT;
118int ipc_min_cycle = RADIX_TREE_MAP_SIZE;
119
120static struct ctl_table ipc_kern_table[] = {
121	{
122		.procname	= "shmmax",
123		.data		= &init_ipc_ns.shm_ctlmax,
124		.maxlen		= sizeof(init_ipc_ns.shm_ctlmax),
125		.mode		= 0644,
126		.proc_handler	= proc_ipc_doulongvec_minmax,
127	},
128	{
129		.procname	= "shmall",
130		.data		= &init_ipc_ns.shm_ctlall,
131		.maxlen		= sizeof(init_ipc_ns.shm_ctlall),
132		.mode		= 0644,
133		.proc_handler	= proc_ipc_doulongvec_minmax,
134	},
135	{
136		.procname	= "shmmni",
137		.data		= &init_ipc_ns.shm_ctlmni,
138		.maxlen		= sizeof(init_ipc_ns.shm_ctlmni),
139		.mode		= 0644,
140		.proc_handler	= proc_ipc_dointvec_minmax,
141		.extra1		= SYSCTL_ZERO,
142		.extra2		= &ipc_mni,
143	},
144	{
145		.procname	= "shm_rmid_forced",
146		.data		= &init_ipc_ns.shm_rmid_forced,
147		.maxlen		= sizeof(init_ipc_ns.shm_rmid_forced),
148		.mode		= 0644,
149		.proc_handler	= proc_ipc_dointvec_minmax_orphans,
150		.extra1		= SYSCTL_ZERO,
151		.extra2		= SYSCTL_ONE,
152	},
153	{
154		.procname	= "msgmax",
155		.data		= &init_ipc_ns.msg_ctlmax,
156		.maxlen		= sizeof(init_ipc_ns.msg_ctlmax),
157		.mode		= 0644,
158		.proc_handler	= proc_ipc_dointvec_minmax,
159		.extra1		= SYSCTL_ZERO,
160		.extra2		= SYSCTL_INT_MAX,
161	},
162	{
163		.procname	= "msgmni",
164		.data		= &init_ipc_ns.msg_ctlmni,
165		.maxlen		= sizeof(init_ipc_ns.msg_ctlmni),
166		.mode		= 0644,
167		.proc_handler	= proc_ipc_dointvec_minmax,
168		.extra1		= SYSCTL_ZERO,
169		.extra2		= &ipc_mni,
170	},
171	{
172		.procname	= "auto_msgmni",
173		.data		= NULL,
174		.maxlen		= sizeof(int),
175		.mode		= 0644,
176		.proc_handler	= proc_ipc_auto_msgmni,
177		.extra1		= SYSCTL_ZERO,
178		.extra2		= SYSCTL_ONE,
179	},
180	{
181		.procname	=  "msgmnb",
182		.data		= &init_ipc_ns.msg_ctlmnb,
183		.maxlen		= sizeof(init_ipc_ns.msg_ctlmnb),
184		.mode		= 0644,
185		.proc_handler	= proc_ipc_dointvec_minmax,
186		.extra1		= SYSCTL_ZERO,
187		.extra2		= SYSCTL_INT_MAX,
188	},
189	{
190		.procname	= "sem",
191		.data		= &init_ipc_ns.sem_ctls,
192		.maxlen		= 4*sizeof(int),
193		.mode		= 0644,
194		.proc_handler	= proc_ipc_sem_dointvec,
195	},
196#ifdef CONFIG_CHECKPOINT_RESTORE
197	{
198		.procname	= "sem_next_id",
199		.data		= &init_ipc_ns.ids[IPC_SEM_IDS].next_id,
200		.maxlen		= sizeof(init_ipc_ns.ids[IPC_SEM_IDS].next_id),
201		.mode		= 0644,
202		.proc_handler	= proc_ipc_dointvec_minmax,
203		.extra1		= SYSCTL_ZERO,
204		.extra2		= SYSCTL_INT_MAX,
205	},
206	{
207		.procname	= "msg_next_id",
208		.data		= &init_ipc_ns.ids[IPC_MSG_IDS].next_id,
209		.maxlen		= sizeof(init_ipc_ns.ids[IPC_MSG_IDS].next_id),
210		.mode		= 0644,
211		.proc_handler	= proc_ipc_dointvec_minmax,
212		.extra1		= SYSCTL_ZERO,
213		.extra2		= SYSCTL_INT_MAX,
214	},
215	{
216		.procname	= "shm_next_id",
217		.data		= &init_ipc_ns.ids[IPC_SHM_IDS].next_id,
218		.maxlen		= sizeof(init_ipc_ns.ids[IPC_SHM_IDS].next_id),
219		.mode		= 0644,
220		.proc_handler	= proc_ipc_dointvec_minmax,
221		.extra1		= SYSCTL_ZERO,
222		.extra2		= SYSCTL_INT_MAX,
223	},
224#endif
225	{}
226};
227
228static struct ctl_table ipc_root_table[] = {
229	{
230		.procname	= "kernel",
231		.mode		= 0555,
232		.child		= ipc_kern_table,
233	},
234	{}
235};
236
237static int __init ipc_sysctl_init(void)
238{
239	register_sysctl_table(ipc_root_table);
240	return 0;
241}
242
243device_initcall(ipc_sysctl_init);
244
245static int __init ipc_mni_extend(char *str)
246{
247	ipc_mni = IPCMNI_EXTEND;
248	ipc_mni_shift = IPCMNI_EXTEND_SHIFT;
249	ipc_min_cycle = IPCMNI_EXTEND_MIN_CYCLE;
250	pr_info("IPCMNI extended to %d.\n", ipc_mni);
251	return 0;
252}
253early_param("ipcmni_extend", ipc_mni_extend);
254