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/capability.h>
14 #include <linux/ipc_namespace.h>
15 #include <linux/msg.h>
16 #include <linux/slab.h>
17 #include "util.h"
18
proc_ipc_dointvec_minmax_orphans(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)19 static int proc_ipc_dointvec_minmax_orphans(struct ctl_table *table, int write,
20 void *buffer, size_t *lenp, loff_t *ppos)
21 {
22 struct ipc_namespace *ns =
23 container_of(table->data, struct ipc_namespace, shm_rmid_forced);
24 int err;
25
26 err = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
27
28 if (err < 0)
29 return err;
30 if (ns->shm_rmid_forced)
31 shm_destroy_orphaned(ns);
32 return err;
33 }
34
proc_ipc_auto_msgmni(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)35 static int proc_ipc_auto_msgmni(struct ctl_table *table, int write,
36 void *buffer, size_t *lenp, loff_t *ppos)
37 {
38 struct ctl_table ipc_table;
39 int dummy = 0;
40
41 memcpy(&ipc_table, table, sizeof(ipc_table));
42 ipc_table.data = &dummy;
43
44 if (write)
45 pr_info_once("writing to auto_msgmni has no effect");
46
47 return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
48 }
49
proc_ipc_sem_dointvec(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)50 static int proc_ipc_sem_dointvec(struct ctl_table *table, int write,
51 void *buffer, size_t *lenp, loff_t *ppos)
52 {
53 struct ipc_namespace *ns =
54 container_of(table->data, struct ipc_namespace, sem_ctls);
55 int ret, semmni;
56
57 semmni = ns->sem_ctls[3];
58 ret = proc_dointvec(table, write, buffer, lenp, ppos);
59
60 if (!ret)
61 ret = sem_check_semmni(ns);
62
63 /*
64 * Reset the semmni value if an error happens.
65 */
66 if (ret)
67 ns->sem_ctls[3] = semmni;
68 return ret;
69 }
70
71 int ipc_mni = IPCMNI;
72 int ipc_mni_shift = IPCMNI_SHIFT;
73 int ipc_min_cycle = RADIX_TREE_MAP_SIZE;
74
75 static struct ctl_table ipc_sysctls[] = {
76 {
77 .procname = "shmmax",
78 .data = &init_ipc_ns.shm_ctlmax,
79 .maxlen = sizeof(init_ipc_ns.shm_ctlmax),
80 .mode = 0644,
81 .proc_handler = proc_doulongvec_minmax,
82 },
83 {
84 .procname = "shmall",
85 .data = &init_ipc_ns.shm_ctlall,
86 .maxlen = sizeof(init_ipc_ns.shm_ctlall),
87 .mode = 0644,
88 .proc_handler = proc_doulongvec_minmax,
89 },
90 {
91 .procname = "shmmni",
92 .data = &init_ipc_ns.shm_ctlmni,
93 .maxlen = sizeof(init_ipc_ns.shm_ctlmni),
94 .mode = 0644,
95 .proc_handler = proc_dointvec_minmax,
96 .extra1 = SYSCTL_ZERO,
97 .extra2 = &ipc_mni,
98 },
99 {
100 .procname = "shm_rmid_forced",
101 .data = &init_ipc_ns.shm_rmid_forced,
102 .maxlen = sizeof(init_ipc_ns.shm_rmid_forced),
103 .mode = 0644,
104 .proc_handler = proc_ipc_dointvec_minmax_orphans,
105 .extra1 = SYSCTL_ZERO,
106 .extra2 = SYSCTL_ONE,
107 },
108 {
109 .procname = "msgmax",
110 .data = &init_ipc_ns.msg_ctlmax,
111 .maxlen = sizeof(init_ipc_ns.msg_ctlmax),
112 .mode = 0644,
113 .proc_handler = proc_dointvec_minmax,
114 .extra1 = SYSCTL_ZERO,
115 .extra2 = SYSCTL_INT_MAX,
116 },
117 {
118 .procname = "msgmni",
119 .data = &init_ipc_ns.msg_ctlmni,
120 .maxlen = sizeof(init_ipc_ns.msg_ctlmni),
121 .mode = 0644,
122 .proc_handler = proc_dointvec_minmax,
123 .extra1 = SYSCTL_ZERO,
124 .extra2 = &ipc_mni,
125 },
126 {
127 .procname = "auto_msgmni",
128 .data = NULL,
129 .maxlen = sizeof(int),
130 .mode = 0644,
131 .proc_handler = proc_ipc_auto_msgmni,
132 .extra1 = SYSCTL_ZERO,
133 .extra2 = SYSCTL_ONE,
134 },
135 {
136 .procname = "msgmnb",
137 .data = &init_ipc_ns.msg_ctlmnb,
138 .maxlen = sizeof(init_ipc_ns.msg_ctlmnb),
139 .mode = 0644,
140 .proc_handler = proc_dointvec_minmax,
141 .extra1 = SYSCTL_ZERO,
142 .extra2 = SYSCTL_INT_MAX,
143 },
144 {
145 .procname = "sem",
146 .data = &init_ipc_ns.sem_ctls,
147 .maxlen = 4*sizeof(int),
148 .mode = 0644,
149 .proc_handler = proc_ipc_sem_dointvec,
150 },
151 #ifdef CONFIG_CHECKPOINT_RESTORE
152 {
153 .procname = "sem_next_id",
154 .data = &init_ipc_ns.ids[IPC_SEM_IDS].next_id,
155 .maxlen = sizeof(init_ipc_ns.ids[IPC_SEM_IDS].next_id),
156 .mode = 0444,
157 .proc_handler = proc_dointvec_minmax,
158 .extra1 = SYSCTL_ZERO,
159 .extra2 = SYSCTL_INT_MAX,
160 },
161 {
162 .procname = "msg_next_id",
163 .data = &init_ipc_ns.ids[IPC_MSG_IDS].next_id,
164 .maxlen = sizeof(init_ipc_ns.ids[IPC_MSG_IDS].next_id),
165 .mode = 0444,
166 .proc_handler = proc_dointvec_minmax,
167 .extra1 = SYSCTL_ZERO,
168 .extra2 = SYSCTL_INT_MAX,
169 },
170 {
171 .procname = "shm_next_id",
172 .data = &init_ipc_ns.ids[IPC_SHM_IDS].next_id,
173 .maxlen = sizeof(init_ipc_ns.ids[IPC_SHM_IDS].next_id),
174 .mode = 0444,
175 .proc_handler = proc_dointvec_minmax,
176 .extra1 = SYSCTL_ZERO,
177 .extra2 = SYSCTL_INT_MAX,
178 },
179 #endif
180 {}
181 };
182
set_lookup(struct ctl_table_root * root)183 static struct ctl_table_set *set_lookup(struct ctl_table_root *root)
184 {
185 return ¤t->nsproxy->ipc_ns->ipc_set;
186 }
187
set_is_seen(struct ctl_table_set * set)188 static int set_is_seen(struct ctl_table_set *set)
189 {
190 return ¤t->nsproxy->ipc_ns->ipc_set == set;
191 }
192
ipc_permissions(struct ctl_table_header * head,struct ctl_table * table)193 static int ipc_permissions(struct ctl_table_header *head, struct ctl_table *table)
194 {
195 int mode = table->mode;
196
197 #ifdef CONFIG_CHECKPOINT_RESTORE
198 struct ipc_namespace *ns = current->nsproxy->ipc_ns;
199
200 if (((table->data == &ns->ids[IPC_SEM_IDS].next_id) ||
201 (table->data == &ns->ids[IPC_MSG_IDS].next_id) ||
202 (table->data == &ns->ids[IPC_SHM_IDS].next_id)) &&
203 checkpoint_restore_ns_capable(ns->user_ns))
204 mode = 0666;
205 #endif
206 return mode;
207 }
208
209 static struct ctl_table_root set_root = {
210 .lookup = set_lookup,
211 .permissions = ipc_permissions,
212 };
213
setup_ipc_sysctls(struct ipc_namespace * ns)214 bool setup_ipc_sysctls(struct ipc_namespace *ns)
215 {
216 struct ctl_table *tbl;
217
218 setup_sysctl_set(&ns->ipc_set, &set_root, set_is_seen);
219
220 tbl = kmemdup(ipc_sysctls, sizeof(ipc_sysctls), GFP_KERNEL);
221 if (tbl) {
222 int i;
223
224 for (i = 0; i < ARRAY_SIZE(ipc_sysctls); i++) {
225 if (tbl[i].data == &init_ipc_ns.shm_ctlmax)
226 tbl[i].data = &ns->shm_ctlmax;
227
228 else if (tbl[i].data == &init_ipc_ns.shm_ctlall)
229 tbl[i].data = &ns->shm_ctlall;
230
231 else if (tbl[i].data == &init_ipc_ns.shm_ctlmni)
232 tbl[i].data = &ns->shm_ctlmni;
233
234 else if (tbl[i].data == &init_ipc_ns.shm_rmid_forced)
235 tbl[i].data = &ns->shm_rmid_forced;
236
237 else if (tbl[i].data == &init_ipc_ns.msg_ctlmax)
238 tbl[i].data = &ns->msg_ctlmax;
239
240 else if (tbl[i].data == &init_ipc_ns.msg_ctlmni)
241 tbl[i].data = &ns->msg_ctlmni;
242
243 else if (tbl[i].data == &init_ipc_ns.msg_ctlmnb)
244 tbl[i].data = &ns->msg_ctlmnb;
245
246 else if (tbl[i].data == &init_ipc_ns.sem_ctls)
247 tbl[i].data = &ns->sem_ctls;
248 #ifdef CONFIG_CHECKPOINT_RESTORE
249 else if (tbl[i].data == &init_ipc_ns.ids[IPC_SEM_IDS].next_id)
250 tbl[i].data = &ns->ids[IPC_SEM_IDS].next_id;
251
252 else if (tbl[i].data == &init_ipc_ns.ids[IPC_MSG_IDS].next_id)
253 tbl[i].data = &ns->ids[IPC_MSG_IDS].next_id;
254
255 else if (tbl[i].data == &init_ipc_ns.ids[IPC_SHM_IDS].next_id)
256 tbl[i].data = &ns->ids[IPC_SHM_IDS].next_id;
257 #endif
258 else
259 tbl[i].data = NULL;
260 }
261
262 ns->ipc_sysctls = __register_sysctl_table(&ns->ipc_set,
263 "kernel", tbl,
264 ARRAY_SIZE(ipc_sysctls));
265 }
266 if (!ns->ipc_sysctls) {
267 kfree(tbl);
268 retire_sysctl_set(&ns->ipc_set);
269 return false;
270 }
271
272 return true;
273 }
274
retire_ipc_sysctls(struct ipc_namespace * ns)275 void retire_ipc_sysctls(struct ipc_namespace *ns)
276 {
277 struct ctl_table *tbl;
278
279 tbl = ns->ipc_sysctls->ctl_table_arg;
280 unregister_sysctl_table(ns->ipc_sysctls);
281 retire_sysctl_set(&ns->ipc_set);
282 kfree(tbl);
283 }
284
ipc_sysctl_init(void)285 static int __init ipc_sysctl_init(void)
286 {
287 if (!setup_ipc_sysctls(&init_ipc_ns)) {
288 pr_warn("ipc sysctl registration failed\n");
289 return -ENOMEM;
290 }
291 return 0;
292 }
293
294 device_initcall(ipc_sysctl_init);
295
ipc_mni_extend(char * str)296 static int __init ipc_mni_extend(char *str)
297 {
298 ipc_mni = IPCMNI_EXTEND;
299 ipc_mni_shift = IPCMNI_EXTEND_SHIFT;
300 ipc_min_cycle = IPCMNI_EXTEND_MIN_CYCLE;
301 pr_info("IPCMNI extended to %d.\n", ipc_mni);
302 return 0;
303 }
304 early_param("ipcmni_extend", ipc_mni_extend);
305
