ipc_sysctl.c revision b886d83c
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 __user *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 __user *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 __user *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 __user *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 __user *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
116static int zero;
117static int one = 1;
118static int int_max = INT_MAX;
119int ipc_mni = IPCMNI;
120int ipc_mni_shift = IPCMNI_SHIFT;
121int ipc_min_cycle = RADIX_TREE_MAP_SIZE;
122
123static struct ctl_table ipc_kern_table[] = {
124	{
125		.procname	= "shmmax",
126		.data		= &init_ipc_ns.shm_ctlmax,
127		.maxlen		= sizeof(init_ipc_ns.shm_ctlmax),
128		.mode		= 0644,
129		.proc_handler	= proc_ipc_doulongvec_minmax,
130	},
131	{
132		.procname	= "shmall",
133		.data		= &init_ipc_ns.shm_ctlall,
134		.maxlen		= sizeof(init_ipc_ns.shm_ctlall),
135		.mode		= 0644,
136		.proc_handler	= proc_ipc_doulongvec_minmax,
137	},
138	{
139		.procname	= "shmmni",
140		.data		= &init_ipc_ns.shm_ctlmni,
141		.maxlen		= sizeof(init_ipc_ns.shm_ctlmni),
142		.mode		= 0644,
143		.proc_handler	= proc_ipc_dointvec_minmax,
144		.extra1		= &zero,
145		.extra2		= &ipc_mni,
146	},
147	{
148		.procname	= "shm_rmid_forced",
149		.data		= &init_ipc_ns.shm_rmid_forced,
150		.maxlen		= sizeof(init_ipc_ns.shm_rmid_forced),
151		.mode		= 0644,
152		.proc_handler	= proc_ipc_dointvec_minmax_orphans,
153		.extra1		= &zero,
154		.extra2		= &one,
155	},
156	{
157		.procname	= "msgmax",
158		.data		= &init_ipc_ns.msg_ctlmax,
159		.maxlen		= sizeof(init_ipc_ns.msg_ctlmax),
160		.mode		= 0644,
161		.proc_handler	= proc_ipc_dointvec_minmax,
162		.extra1		= &zero,
163		.extra2		= &int_max,
164	},
165	{
166		.procname	= "msgmni",
167		.data		= &init_ipc_ns.msg_ctlmni,
168		.maxlen		= sizeof(init_ipc_ns.msg_ctlmni),
169		.mode		= 0644,
170		.proc_handler	= proc_ipc_dointvec_minmax,
171		.extra1		= &zero,
172		.extra2		= &ipc_mni,
173	},
174	{
175		.procname	= "auto_msgmni",
176		.data		= NULL,
177		.maxlen		= sizeof(int),
178		.mode		= 0644,
179		.proc_handler	= proc_ipc_auto_msgmni,
180		.extra1		= &zero,
181		.extra2		= &one,
182	},
183	{
184		.procname	=  "msgmnb",
185		.data		= &init_ipc_ns.msg_ctlmnb,
186		.maxlen		= sizeof(init_ipc_ns.msg_ctlmnb),
187		.mode		= 0644,
188		.proc_handler	= proc_ipc_dointvec_minmax,
189		.extra1		= &zero,
190		.extra2		= &int_max,
191	},
192	{
193		.procname	= "sem",
194		.data		= &init_ipc_ns.sem_ctls,
195		.maxlen		= 4*sizeof(int),
196		.mode		= 0644,
197		.proc_handler	= proc_ipc_sem_dointvec,
198	},
199#ifdef CONFIG_CHECKPOINT_RESTORE
200	{
201		.procname	= "sem_next_id",
202		.data		= &init_ipc_ns.ids[IPC_SEM_IDS].next_id,
203		.maxlen		= sizeof(init_ipc_ns.ids[IPC_SEM_IDS].next_id),
204		.mode		= 0644,
205		.proc_handler	= proc_ipc_dointvec_minmax,
206		.extra1		= &zero,
207		.extra2		= &int_max,
208	},
209	{
210		.procname	= "msg_next_id",
211		.data		= &init_ipc_ns.ids[IPC_MSG_IDS].next_id,
212		.maxlen		= sizeof(init_ipc_ns.ids[IPC_MSG_IDS].next_id),
213		.mode		= 0644,
214		.proc_handler	= proc_ipc_dointvec_minmax,
215		.extra1		= &zero,
216		.extra2		= &int_max,
217	},
218	{
219		.procname	= "shm_next_id",
220		.data		= &init_ipc_ns.ids[IPC_SHM_IDS].next_id,
221		.maxlen		= sizeof(init_ipc_ns.ids[IPC_SHM_IDS].next_id),
222		.mode		= 0644,
223		.proc_handler	= proc_ipc_dointvec_minmax,
224		.extra1		= &zero,
225		.extra2		= &int_max,
226	},
227#endif
228	{}
229};
230
231static struct ctl_table ipc_root_table[] = {
232	{
233		.procname	= "kernel",
234		.mode		= 0555,
235		.child		= ipc_kern_table,
236	},
237	{}
238};
239
240static int __init ipc_sysctl_init(void)
241{
242	register_sysctl_table(ipc_root_table);
243	return 0;
244}
245
246device_initcall(ipc_sysctl_init);
247
248static int __init ipc_mni_extend(char *str)
249{
250	ipc_mni = IPCMNI_EXTEND;
251	ipc_mni_shift = IPCMNI_EXTEND_SHIFT;
252	ipc_min_cycle = IPCMNI_EXTEND_MIN_CYCLE;
253	pr_info("IPCMNI extended to %d.\n", ipc_mni);
254	return 0;
255}
256early_param("ipcmni_extend", ipc_mni_extend);
257