xref: /linux/ipc/ipc_sysctl.c (revision fff1662c)
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 
get_ipc(struct ctl_table * table)17 static 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
proc_ipc_dointvec(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)26 static 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 
proc_ipc_dointvec_minmax(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)37 static 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 
proc_ipc_dointvec_minmax_orphans(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)48 static 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 
proc_ipc_doulongvec_minmax(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)61 static 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 
proc_ipc_auto_msgmni(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)72 static 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 
proc_ipc_sem_dointvec(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)87 static int proc_ipc_sem_dointvec(struct ctl_table *table, int write,
88 	void *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 
116 int ipc_mni = IPCMNI;
117 int ipc_mni_shift = IPCMNI_SHIFT;
118 int ipc_min_cycle = RADIX_TREE_MAP_SIZE;
119 
120 static 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 
228 static struct ctl_table ipc_root_table[] = {
229 	{
230 		.procname	= "kernel",
231 		.mode		= 0555,
232 		.child		= ipc_kern_table,
233 	},
234 	{}
235 };
236 
ipc_sysctl_init(void)237 static int __init ipc_sysctl_init(void)
238 {
239 	register_sysctl_table(ipc_root_table);
240 	return 0;
241 }
242 
243 device_initcall(ipc_sysctl_init);
244 
ipc_mni_extend(char * str)245 static 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 }
253 early_param("ipcmni_extend", ipc_mni_extend);
254