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 <linux/cred.h>
18 #include "util.h"
19
proc_ipc_dointvec_minmax_orphans(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)20 static int proc_ipc_dointvec_minmax_orphans(struct ctl_table *table, int write,
21 void *buffer, size_t *lenp, loff_t *ppos)
22 {
23 struct ipc_namespace *ns =
24 container_of(table->data, struct ipc_namespace, shm_rmid_forced);
25 int err;
26
27 err = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
28
29 if (err < 0)
30 return err;
31 if (ns->shm_rmid_forced)
32 shm_destroy_orphaned(ns);
33 return err;
34 }
35
proc_ipc_auto_msgmni(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)36 static int proc_ipc_auto_msgmni(struct ctl_table *table, int write,
37 void *buffer, size_t *lenp, loff_t *ppos)
38 {
39 struct ctl_table ipc_table;
40 int dummy = 0;
41
42 memcpy(&ipc_table, table, sizeof(ipc_table));
43 ipc_table.data = &dummy;
44
45 if (write)
46 pr_info_once("writing to auto_msgmni has no effect");
47
48 return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
49 }
50
proc_ipc_sem_dointvec(struct ctl_table * table,int write,void * buffer,size_t * lenp,loff_t * ppos)51 static int proc_ipc_sem_dointvec(struct ctl_table *table, int write,
52 void *buffer, size_t *lenp, loff_t *ppos)
53 {
54 struct ipc_namespace *ns =
55 container_of(table->data, struct ipc_namespace, sem_ctls);
56 int ret, semmni;
57
58 semmni = ns->sem_ctls[3];
59 ret = proc_dointvec(table, write, buffer, lenp, ppos);
60
61 if (!ret)
62 ret = sem_check_semmni(ns);
63
64 /*
65 * Reset the semmni value if an error happens.
66 */
67 if (ret)
68 ns->sem_ctls[3] = semmni;
69 return ret;
70 }
71
72 int ipc_mni = IPCMNI;
73 int ipc_mni_shift = IPCMNI_SHIFT;
74 int ipc_min_cycle = RADIX_TREE_MAP_SIZE;
75
76 static struct ctl_table ipc_sysctls[] = {
77 {
78 .procname = "shmmax",
79 .data = &init_ipc_ns.shm_ctlmax,
80 .maxlen = sizeof(init_ipc_ns.shm_ctlmax),
81 .mode = 0644,
82 .proc_handler = proc_doulongvec_minmax,
83 },
84 {
85 .procname = "shmall",
86 .data = &init_ipc_ns.shm_ctlall,
87 .maxlen = sizeof(init_ipc_ns.shm_ctlall),
88 .mode = 0644,
89 .proc_handler = proc_doulongvec_minmax,
90 },
91 {
92 .procname = "shmmni",
93 .data = &init_ipc_ns.shm_ctlmni,
94 .maxlen = sizeof(init_ipc_ns.shm_ctlmni),
95 .mode = 0644,
96 .proc_handler = proc_dointvec_minmax,
97 .extra1 = SYSCTL_ZERO,
98 .extra2 = &ipc_mni,
99 },
100 {
101 .procname = "shm_rmid_forced",
102 .data = &init_ipc_ns.shm_rmid_forced,
103 .maxlen = sizeof(init_ipc_ns.shm_rmid_forced),
104 .mode = 0644,
105 .proc_handler = proc_ipc_dointvec_minmax_orphans,
106 .extra1 = SYSCTL_ZERO,
107 .extra2 = SYSCTL_ONE,
108 },
109 {
110 .procname = "msgmax",
111 .data = &init_ipc_ns.msg_ctlmax,
112 .maxlen = sizeof(init_ipc_ns.msg_ctlmax),
113 .mode = 0644,
114 .proc_handler = proc_dointvec_minmax,
115 .extra1 = SYSCTL_ZERO,
116 .extra2 = SYSCTL_INT_MAX,
117 },
118 {
119 .procname = "msgmni",
120 .data = &init_ipc_ns.msg_ctlmni,
121 .maxlen = sizeof(init_ipc_ns.msg_ctlmni),
122 .mode = 0644,
123 .proc_handler = proc_dointvec_minmax,
124 .extra1 = SYSCTL_ZERO,
125 .extra2 = &ipc_mni,
126 },
127 {
128 .procname = "auto_msgmni",
129 .data = NULL,
130 .maxlen = sizeof(int),
131 .mode = 0644,
132 .proc_handler = proc_ipc_auto_msgmni,
133 .extra1 = SYSCTL_ZERO,
134 .extra2 = SYSCTL_ONE,
135 },
136 {
137 .procname = "msgmnb",
138 .data = &init_ipc_ns.msg_ctlmnb,
139 .maxlen = sizeof(init_ipc_ns.msg_ctlmnb),
140 .mode = 0644,
141 .proc_handler = proc_dointvec_minmax,
142 .extra1 = SYSCTL_ZERO,
143 .extra2 = SYSCTL_INT_MAX,
144 },
145 {
146 .procname = "sem",
147 .data = &init_ipc_ns.sem_ctls,
148 .maxlen = 4*sizeof(int),
149 .mode = 0644,
150 .proc_handler = proc_ipc_sem_dointvec,
151 },
152 #ifdef CONFIG_CHECKPOINT_RESTORE
153 {
154 .procname = "sem_next_id",
155 .data = &init_ipc_ns.ids[IPC_SEM_IDS].next_id,
156 .maxlen = sizeof(init_ipc_ns.ids[IPC_SEM_IDS].next_id),
157 .mode = 0444,
158 .proc_handler = proc_dointvec_minmax,
159 .extra1 = SYSCTL_ZERO,
160 .extra2 = SYSCTL_INT_MAX,
161 },
162 {
163 .procname = "msg_next_id",
164 .data = &init_ipc_ns.ids[IPC_MSG_IDS].next_id,
165 .maxlen = sizeof(init_ipc_ns.ids[IPC_MSG_IDS].next_id),
166 .mode = 0444,
167 .proc_handler = proc_dointvec_minmax,
168 .extra1 = SYSCTL_ZERO,
169 .extra2 = SYSCTL_INT_MAX,
170 },
171 {
172 .procname = "shm_next_id",
173 .data = &init_ipc_ns.ids[IPC_SHM_IDS].next_id,
174 .maxlen = sizeof(init_ipc_ns.ids[IPC_SHM_IDS].next_id),
175 .mode = 0444,
176 .proc_handler = proc_dointvec_minmax,
177 .extra1 = SYSCTL_ZERO,
178 .extra2 = SYSCTL_INT_MAX,
179 },
180 #endif
181 {}
182 };
183
set_lookup(struct ctl_table_root * root)184 static struct ctl_table_set *set_lookup(struct ctl_table_root *root)
185 {
186 return ¤t->nsproxy->ipc_ns->ipc_set;
187 }
188
set_is_seen(struct ctl_table_set * set)189 static int set_is_seen(struct ctl_table_set *set)
190 {
191 return ¤t->nsproxy->ipc_ns->ipc_set == set;
192 }
193
ipc_set_ownership(struct ctl_table_header * head,kuid_t * uid,kgid_t * gid)194 static void ipc_set_ownership(struct ctl_table_header *head,
195 kuid_t *uid, kgid_t *gid)
196 {
197 struct ipc_namespace *ns =
198 container_of(head->set, struct ipc_namespace, ipc_set);
199
200 kuid_t ns_root_uid = make_kuid(ns->user_ns, 0);
201 kgid_t ns_root_gid = make_kgid(ns->user_ns, 0);
202
203 *uid = uid_valid(ns_root_uid) ? ns_root_uid : GLOBAL_ROOT_UID;
204 *gid = gid_valid(ns_root_gid) ? ns_root_gid : GLOBAL_ROOT_GID;
205 }
206
ipc_permissions(struct ctl_table_header * head,struct ctl_table * table)207 static int ipc_permissions(struct ctl_table_header *head, struct ctl_table *table)
208 {
209 int mode = table->mode;
210
211 #ifdef CONFIG_CHECKPOINT_RESTORE
212 struct ipc_namespace *ns =
213 container_of(head->set, struct ipc_namespace, ipc_set);
214
215 if (((table->data == &ns->ids[IPC_SEM_IDS].next_id) ||
216 (table->data == &ns->ids[IPC_MSG_IDS].next_id) ||
217 (table->data == &ns->ids[IPC_SHM_IDS].next_id)) &&
218 checkpoint_restore_ns_capable(ns->user_ns))
219 mode = 0666;
220 else
221 #endif
222 {
223 kuid_t ns_root_uid;
224 kgid_t ns_root_gid;
225
226 ipc_set_ownership(head, &ns_root_uid, &ns_root_gid);
227
228 if (uid_eq(current_euid(), ns_root_uid))
229 mode >>= 6;
230
231 else if (in_egroup_p(ns_root_gid))
232 mode >>= 3;
233 }
234
235 mode &= 7;
236
237 return (mode << 6) | (mode << 3) | mode;
238 }
239
240 static struct ctl_table_root set_root = {
241 .lookup = set_lookup,
242 .permissions = ipc_permissions,
243 .set_ownership = ipc_set_ownership,
244 };
245
setup_ipc_sysctls(struct ipc_namespace * ns)246 bool setup_ipc_sysctls(struct ipc_namespace *ns)
247 {
248 struct ctl_table *tbl;
249
250 setup_sysctl_set(&ns->ipc_set, &set_root, set_is_seen);
251
252 tbl = kmemdup(ipc_sysctls, sizeof(ipc_sysctls), GFP_KERNEL);
253 if (tbl) {
254 int i;
255
256 for (i = 0; i < ARRAY_SIZE(ipc_sysctls); i++) {
257 if (tbl[i].data == &init_ipc_ns.shm_ctlmax)
258 tbl[i].data = &ns->shm_ctlmax;
259
260 else if (tbl[i].data == &init_ipc_ns.shm_ctlall)
261 tbl[i].data = &ns->shm_ctlall;
262
263 else if (tbl[i].data == &init_ipc_ns.shm_ctlmni)
264 tbl[i].data = &ns->shm_ctlmni;
265
266 else if (tbl[i].data == &init_ipc_ns.shm_rmid_forced)
267 tbl[i].data = &ns->shm_rmid_forced;
268
269 else if (tbl[i].data == &init_ipc_ns.msg_ctlmax)
270 tbl[i].data = &ns->msg_ctlmax;
271
272 else if (tbl[i].data == &init_ipc_ns.msg_ctlmni)
273 tbl[i].data = &ns->msg_ctlmni;
274
275 else if (tbl[i].data == &init_ipc_ns.msg_ctlmnb)
276 tbl[i].data = &ns->msg_ctlmnb;
277
278 else if (tbl[i].data == &init_ipc_ns.sem_ctls)
279 tbl[i].data = &ns->sem_ctls;
280 #ifdef CONFIG_CHECKPOINT_RESTORE
281 else if (tbl[i].data == &init_ipc_ns.ids[IPC_SEM_IDS].next_id)
282 tbl[i].data = &ns->ids[IPC_SEM_IDS].next_id;
283
284 else if (tbl[i].data == &init_ipc_ns.ids[IPC_MSG_IDS].next_id)
285 tbl[i].data = &ns->ids[IPC_MSG_IDS].next_id;
286
287 else if (tbl[i].data == &init_ipc_ns.ids[IPC_SHM_IDS].next_id)
288 tbl[i].data = &ns->ids[IPC_SHM_IDS].next_id;
289 #endif
290 else
291 tbl[i].data = NULL;
292 }
293
294 ns->ipc_sysctls = __register_sysctl_table(&ns->ipc_set,
295 "kernel", tbl,
296 ARRAY_SIZE(ipc_sysctls));
297 }
298 if (!ns->ipc_sysctls) {
299 kfree(tbl);
300 retire_sysctl_set(&ns->ipc_set);
301 return false;
302 }
303
304 return true;
305 }
306
retire_ipc_sysctls(struct ipc_namespace * ns)307 void retire_ipc_sysctls(struct ipc_namespace *ns)
308 {
309 struct ctl_table *tbl;
310
311 tbl = ns->ipc_sysctls->ctl_table_arg;
312 unregister_sysctl_table(ns->ipc_sysctls);
313 retire_sysctl_set(&ns->ipc_set);
314 kfree(tbl);
315 }
316
ipc_sysctl_init(void)317 static int __init ipc_sysctl_init(void)
318 {
319 if (!setup_ipc_sysctls(&init_ipc_ns)) {
320 pr_warn("ipc sysctl registration failed\n");
321 return -ENOMEM;
322 }
323 return 0;
324 }
325
326 device_initcall(ipc_sysctl_init);
327
ipc_mni_extend(char * str)328 static int __init ipc_mni_extend(char *str)
329 {
330 ipc_mni = IPCMNI_EXTEND;
331 ipc_mni_shift = IPCMNI_EXTEND_SHIFT;
332 ipc_min_cycle = IPCMNI_EXTEND_MIN_CYCLE;
333 pr_info("IPCMNI extended to %d.\n", ipc_mni);
334 return 0;
335 }
336 early_param("ipcmni_extend", ipc_mni_extend);
337