Commit | Line | Data |
---|---|---|
b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 LT |
2 | /* |
3 | * linux/ipc/util.c | |
4 | * Copyright (C) 1992 Krishna Balasubramanian | |
5 | * | |
6 | * Sep 1997 - Call suser() last after "normal" permission checks so we | |
7 | * get BSD style process accounting right. | |
8 | * Occurs in several places in the IPC code. | |
9 | * Chris Evans, <chris@ferret.lmh.ox.ac.uk> | |
10 | * Nov 1999 - ipc helper functions, unified SMP locking | |
624dffcb | 11 | * Manfred Spraul <manfred@colorfullife.com> |
1da177e4 LT |
12 | * Oct 2002 - One lock per IPC id. RCU ipc_free for lock-free grow_ary(). |
13 | * Mingming Cao <cmm@us.ibm.com> | |
073115d6 SG |
14 | * Mar 2006 - support for audit of ipc object properties |
15 | * Dustin Kirkland <dustin.kirkland@us.ibm.com> | |
73ea4130 KK |
16 | * Jun 2006 - namespaces ssupport |
17 | * OpenVZ, SWsoft Inc. | |
18 | * Pavel Emelianov <xemul@openvz.org> | |
05603c44 DB |
19 | * |
20 | * General sysv ipc locking scheme: | |
18ccee26 DB |
21 | * rcu_read_lock() |
22 | * obtain the ipc object (kern_ipc_perm) by looking up the id in an idr | |
23 | * tree. | |
24 | * - perform initial checks (capabilities, auditing and permission, | |
25 | * etc). | |
26 | * - perform read-only operations, such as STAT, INFO commands. | |
27 | * acquire the ipc lock (kern_ipc_perm.lock) through | |
28 | * ipc_lock_object() | |
29 | * - perform data updates, such as SET, RMID commands and | |
30 | * mechanism-specific operations (semop/semtimedop, | |
31 | * msgsnd/msgrcv, shmat/shmdt). | |
32 | * drop the ipc lock, through ipc_unlock_object(). | |
33 | * rcu_read_unlock() | |
34 | * | |
35 | * The ids->rwsem must be taken when: | |
36 | * - creating, removing and iterating the existing entries in ipc | |
37 | * identifier sets. | |
38 | * - iterating through files under /proc/sysvipc/ | |
39 | * | |
40 | * Note that sems have a special fast path that avoids kern_ipc_perm.lock - | |
41 | * see sem_lock(). | |
1da177e4 LT |
42 | */ |
43 | ||
1da177e4 LT |
44 | #include <linux/mm.h> |
45 | #include <linux/shm.h> | |
46 | #include <linux/init.h> | |
47 | #include <linux/msg.h> | |
1da177e4 LT |
48 | #include <linux/vmalloc.h> |
49 | #include <linux/slab.h> | |
8f68fa2d | 50 | #include <linux/notifier.h> |
c59ede7b | 51 | #include <linux/capability.h> |
1da177e4 LT |
52 | #include <linux/highuid.h> |
53 | #include <linux/security.h> | |
54 | #include <linux/rcupdate.h> | |
55 | #include <linux/workqueue.h> | |
ae781774 MW |
56 | #include <linux/seq_file.h> |
57 | #include <linux/proc_fs.h> | |
073115d6 | 58 | #include <linux/audit.h> |
73ea4130 | 59 | #include <linux/nsproxy.h> |
3e148c79 | 60 | #include <linux/rwsem.h> |
b6b337ad | 61 | #include <linux/memory.h> |
ae5e1b22 | 62 | #include <linux/ipc_namespace.h> |
1da177e4 LT |
63 | |
64 | #include <asm/unistd.h> | |
65 | ||
66 | #include "util.h" | |
67 | ||
ae781774 MW |
68 | struct ipc_proc_iface { |
69 | const char *path; | |
70 | const char *header; | |
73ea4130 | 71 | int ids; |
ae781774 MW |
72 | int (*show)(struct seq_file *, void *); |
73 | }; | |
74 | ||
1da177e4 | 75 | /** |
8001c858 | 76 | * ipc_init - initialise ipc subsystem |
1da177e4 | 77 | * |
8001c858 DB |
78 | * The various sysv ipc resources (semaphores, messages and shared |
79 | * memory) are initialised. | |
80 | * | |
81 | * A callback routine is registered into the memory hotplug notifier | |
82 | * chain: since msgmni scales to lowmem this callback routine will be | |
83 | * called upon successful memory add / remove to recompute msmgni. | |
1da177e4 | 84 | */ |
1da177e4 LT |
85 | static int __init ipc_init(void) |
86 | { | |
0cfb6aee GK |
87 | int err_sem, err_msg; |
88 | ||
89 | err_sem = sem_init(); | |
90 | WARN(err_sem, "ipc: sysv sem_init failed: %d\n", err_sem); | |
91 | err_msg = msg_init(); | |
92 | WARN(err_msg, "ipc: sysv msg_init failed: %d\n", err_msg); | |
1da177e4 | 93 | shm_init(); |
0cfb6aee GK |
94 | |
95 | return err_msg ? err_msg : err_sem; | |
1da177e4 | 96 | } |
6d08a256 | 97 | device_initcall(ipc_init); |
1da177e4 | 98 | |
0cfb6aee GK |
99 | static const struct rhashtable_params ipc_kht_params = { |
100 | .head_offset = offsetof(struct kern_ipc_perm, khtnode), | |
101 | .key_offset = offsetof(struct kern_ipc_perm, key), | |
102 | .key_len = FIELD_SIZEOF(struct kern_ipc_perm, key), | |
103 | .locks_mul = 1, | |
104 | .automatic_shrinking = true, | |
105 | }; | |
106 | ||
1da177e4 | 107 | /** |
8001c858 DB |
108 | * ipc_init_ids - initialise ipc identifiers |
109 | * @ids: ipc identifier set | |
1da177e4 | 110 | * |
8001c858 | 111 | * Set up the sequence range to use for the ipc identifier range (limited |
0cfb6aee | 112 | * below IPCMNI) then initialise the keys hashtable and ids idr. |
1da177e4 | 113 | */ |
0cfb6aee | 114 | int ipc_init_ids(struct ipc_ids *ids) |
1da177e4 | 115 | { |
0cfb6aee | 116 | int err; |
1da177e4 | 117 | ids->in_use = 0; |
1da177e4 | 118 | ids->seq = 0; |
daf948c7 | 119 | init_rwsem(&ids->rwsem); |
0cfb6aee GK |
120 | err = rhashtable_init(&ids->key_ht, &ipc_kht_params); |
121 | if (err) | |
122 | return err; | |
7ca7e564 | 123 | idr_init(&ids->ipcs_idr); |
0cfb6aee | 124 | ids->tables_initialized = true; |
b8fd9983 DB |
125 | #ifdef CONFIG_CHECKPOINT_RESTORE |
126 | ids->next_id = -1; | |
127 | #endif | |
0cfb6aee | 128 | return 0; |
1da177e4 LT |
129 | } |
130 | ||
ae781774 | 131 | #ifdef CONFIG_PROC_FS |
9a32144e | 132 | static const struct file_operations sysvipc_proc_fops; |
ae781774 | 133 | /** |
8001c858 DB |
134 | * ipc_init_proc_interface - create a proc interface for sysipc types using a seq_file interface. |
135 | * @path: Path in procfs | |
136 | * @header: Banner to be printed at the beginning of the file. | |
137 | * @ids: ipc id table to iterate. | |
138 | * @show: show routine. | |
ae781774 MW |
139 | */ |
140 | void __init ipc_init_proc_interface(const char *path, const char *header, | |
73ea4130 | 141 | int ids, int (*show)(struct seq_file *, void *)) |
ae781774 MW |
142 | { |
143 | struct proc_dir_entry *pde; | |
144 | struct ipc_proc_iface *iface; | |
145 | ||
146 | iface = kmalloc(sizeof(*iface), GFP_KERNEL); | |
147 | if (!iface) | |
148 | return; | |
149 | iface->path = path; | |
150 | iface->header = header; | |
151 | iface->ids = ids; | |
152 | iface->show = show; | |
153 | ||
6a6375db DL |
154 | pde = proc_create_data(path, |
155 | S_IRUGO, /* world readable */ | |
156 | NULL, /* parent dir */ | |
157 | &sysvipc_proc_fops, | |
158 | iface); | |
3ab08fe2 | 159 | if (!pde) |
ae781774 | 160 | kfree(iface); |
ae781774 MW |
161 | } |
162 | #endif | |
163 | ||
1da177e4 | 164 | /** |
8001c858 DB |
165 | * ipc_findkey - find a key in an ipc identifier set |
166 | * @ids: ipc identifier set | |
167 | * @key: key to find | |
46c0a8ca | 168 | * |
8001c858 DB |
169 | * Returns the locked pointer to the ipc structure if found or NULL |
170 | * otherwise. If key is found ipc points to the owning ipc structure | |
171 | * | |
0cfb6aee | 172 | * Called with writer ipc_ids.rwsem held. |
1da177e4 | 173 | */ |
7748dbfa | 174 | static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key) |
1da177e4 | 175 | { |
0cfb6aee | 176 | struct kern_ipc_perm *ipcp = NULL; |
7ca7e564 | 177 | |
0cfb6aee GK |
178 | if (likely(ids->tables_initialized)) |
179 | ipcp = rhashtable_lookup_fast(&ids->key_ht, &key, | |
180 | ipc_kht_params); | |
7ca7e564 | 181 | |
0cfb6aee | 182 | if (ipcp) { |
32a27500 | 183 | rcu_read_lock(); |
0cfb6aee GK |
184 | ipc_lock_object(ipcp); |
185 | return ipcp; | |
1da177e4 | 186 | } |
7ca7e564 ND |
187 | |
188 | return NULL; | |
1da177e4 LT |
189 | } |
190 | ||
7ca7e564 | 191 | /** |
8001c858 DB |
192 | * ipc_get_maxid - get the last assigned id |
193 | * @ids: ipc identifier set | |
7ca7e564 | 194 | * |
8001c858 | 195 | * Called with ipc_ids.rwsem held. |
1da177e4 | 196 | */ |
7ca7e564 ND |
197 | int ipc_get_maxid(struct ipc_ids *ids) |
198 | { | |
199 | struct kern_ipc_perm *ipc; | |
200 | int max_id = -1; | |
201 | int total, id; | |
202 | ||
203 | if (ids->in_use == 0) | |
204 | return -1; | |
1da177e4 | 205 | |
7ca7e564 ND |
206 | if (ids->in_use == IPCMNI) |
207 | return IPCMNI - 1; | |
208 | ||
209 | /* Look for the last assigned id */ | |
210 | total = 0; | |
211 | for (id = 0; id < IPCMNI && total < ids->in_use; id++) { | |
212 | ipc = idr_find(&ids->ipcs_idr, id); | |
213 | if (ipc != NULL) { | |
214 | max_id = id; | |
215 | total++; | |
216 | } | |
217 | } | |
218 | return max_id; | |
1da177e4 LT |
219 | } |
220 | ||
b8fd9983 DB |
221 | #ifdef CONFIG_CHECKPOINT_RESTORE |
222 | /* | |
223 | * Specify desired id for next allocated IPC object. | |
224 | */ | |
225 | #define ipc_idr_alloc(ids, new) \ | |
226 | idr_alloc(&(ids)->ipcs_idr, (new), \ | |
227 | (ids)->next_id < 0 ? 0 : ipcid_to_idx((ids)->next_id),\ | |
228 | 0, GFP_NOWAIT) | |
229 | ||
230 | static inline int ipc_buildid(int id, struct ipc_ids *ids, | |
231 | struct kern_ipc_perm *new) | |
232 | { | |
233 | if (ids->next_id < 0) { /* default, behave as !CHECKPOINT_RESTORE */ | |
234 | new->seq = ids->seq++; | |
235 | if (ids->seq > IPCID_SEQ_MAX) | |
236 | ids->seq = 0; | |
237 | } else { | |
238 | new->seq = ipcid_to_seqx(ids->next_id); | |
239 | ids->next_id = -1; | |
240 | } | |
241 | ||
242 | return SEQ_MULTIPLIER * new->seq + id; | |
243 | } | |
244 | ||
245 | #else | |
246 | #define ipc_idr_alloc(ids, new) \ | |
247 | idr_alloc(&(ids)->ipcs_idr, (new), 0, 0, GFP_NOWAIT) | |
248 | ||
249 | static inline int ipc_buildid(int id, struct ipc_ids *ids, | |
250 | struct kern_ipc_perm *new) | |
251 | { | |
252 | new->seq = ids->seq++; | |
253 | if (ids->seq > IPCID_SEQ_MAX) | |
254 | ids->seq = 0; | |
255 | ||
256 | return SEQ_MULTIPLIER * new->seq + id; | |
257 | } | |
258 | ||
259 | #endif /* CONFIG_CHECKPOINT_RESTORE */ | |
260 | ||
1da177e4 | 261 | /** |
8001c858 DB |
262 | * ipc_addid - add an ipc identifier |
263 | * @ids: ipc identifier set | |
264 | * @new: new ipc permission set | |
ebf66799 | 265 | * @limit: limit for the number of used ids |
1da177e4 | 266 | * |
8001c858 DB |
267 | * Add an entry 'new' to the ipc ids idr. The permissions object is |
268 | * initialised and the first free entry is set up and the id assigned | |
269 | * is returned. The 'new' entry is returned in a locked state on success. | |
270 | * On failure the entry is not locked and a negative err-code is returned. | |
1da177e4 | 271 | * |
8001c858 | 272 | * Called with writer ipc_ids.rwsem held. |
1da177e4 | 273 | */ |
ebf66799 | 274 | int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int limit) |
1da177e4 | 275 | { |
1efdb69b EB |
276 | kuid_t euid; |
277 | kgid_t egid; | |
0cfb6aee | 278 | int id, err; |
1da177e4 | 279 | |
ebf66799 DB |
280 | if (limit > IPCMNI) |
281 | limit = IPCMNI; | |
7ca7e564 | 282 | |
ebf66799 | 283 | if (!ids->tables_initialized || ids->in_use >= limit) |
283bb7fa | 284 | return -ENOSPC; |
7ca7e564 | 285 | |
54924ea3 TH |
286 | idr_preload(GFP_KERNEL); |
287 | ||
9405c03e | 288 | refcount_set(&new->refcount, 1); |
e00b4ff7 | 289 | spin_lock_init(&new->lock); |
72a8ff2f | 290 | new->deleted = false; |
e00b4ff7 ND |
291 | rcu_read_lock(); |
292 | spin_lock(&new->lock); | |
293 | ||
b9a53227 LT |
294 | current_euid_egid(&euid, &egid); |
295 | new->cuid = new->uid = euid; | |
296 | new->gid = new->cgid = egid; | |
297 | ||
b8fd9983 | 298 | id = ipc_idr_alloc(ids, new); |
54924ea3 | 299 | idr_preload_end(); |
0cfb6aee GK |
300 | |
301 | if (id >= 0 && new->key != IPC_PRIVATE) { | |
302 | err = rhashtable_insert_fast(&ids->key_ht, &new->khtnode, | |
303 | ipc_kht_params); | |
304 | if (err < 0) { | |
305 | idr_remove(&ids->ipcs_idr, id); | |
306 | id = err; | |
307 | } | |
308 | } | |
54924ea3 | 309 | if (id < 0) { |
e00b4ff7 ND |
310 | spin_unlock(&new->lock); |
311 | rcu_read_unlock(); | |
54924ea3 | 312 | return id; |
e00b4ff7 | 313 | } |
7ca7e564 | 314 | |
1da177e4 | 315 | ids->in_use++; |
b8fd9983 | 316 | new->id = ipc_buildid(id, ids, new); |
1da177e4 | 317 | |
1da177e4 LT |
318 | return id; |
319 | } | |
320 | ||
7748dbfa | 321 | /** |
8001c858 DB |
322 | * ipcget_new - create a new ipc object |
323 | * @ns: ipc namespace | |
da3dae54 | 324 | * @ids: ipc identifier set |
8001c858 DB |
325 | * @ops: the actual creation routine to call |
326 | * @params: its parameters | |
327 | * | |
328 | * This routine is called by sys_msgget, sys_semget() and sys_shmget() | |
329 | * when the key is IPC_PRIVATE. | |
7748dbfa | 330 | */ |
b2d75cdd | 331 | static int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids, |
eb66ec44 | 332 | const struct ipc_ops *ops, struct ipc_params *params) |
7748dbfa ND |
333 | { |
334 | int err; | |
7748dbfa | 335 | |
d9a605e4 | 336 | down_write(&ids->rwsem); |
7748dbfa | 337 | err = ops->getnew(ns, params); |
d9a605e4 | 338 | up_write(&ids->rwsem); |
7748dbfa ND |
339 | return err; |
340 | } | |
341 | ||
342 | /** | |
8001c858 DB |
343 | * ipc_check_perms - check security and permissions for an ipc object |
344 | * @ns: ipc namespace | |
345 | * @ipcp: ipc permission set | |
346 | * @ops: the actual security routine to call | |
347 | * @params: its parameters | |
f4566f04 | 348 | * |
8001c858 DB |
349 | * This routine is called by sys_msgget(), sys_semget() and sys_shmget() |
350 | * when the key is not IPC_PRIVATE and that key already exists in the | |
351 | * ds IDR. | |
f4566f04 | 352 | * |
8001c858 | 353 | * On success, the ipc id is returned. |
f4566f04 | 354 | * |
8001c858 | 355 | * It is called with ipc_ids.rwsem and ipcp->lock held. |
7748dbfa | 356 | */ |
b0e77598 SH |
357 | static int ipc_check_perms(struct ipc_namespace *ns, |
358 | struct kern_ipc_perm *ipcp, | |
eb66ec44 | 359 | const struct ipc_ops *ops, |
b0e77598 | 360 | struct ipc_params *params) |
7748dbfa ND |
361 | { |
362 | int err; | |
363 | ||
b0e77598 | 364 | if (ipcperms(ns, ipcp, params->flg)) |
7748dbfa ND |
365 | err = -EACCES; |
366 | else { | |
367 | err = ops->associate(ipcp, params->flg); | |
368 | if (!err) | |
369 | err = ipcp->id; | |
370 | } | |
371 | ||
372 | return err; | |
373 | } | |
374 | ||
375 | /** | |
8001c858 DB |
376 | * ipcget_public - get an ipc object or create a new one |
377 | * @ns: ipc namespace | |
da3dae54 | 378 | * @ids: ipc identifier set |
8001c858 DB |
379 | * @ops: the actual creation routine to call |
380 | * @params: its parameters | |
381 | * | |
382 | * This routine is called by sys_msgget, sys_semget() and sys_shmget() | |
383 | * when the key is not IPC_PRIVATE. | |
384 | * It adds a new entry if the key is not found and does some permission | |
385 | * / security checkings if the key is found. | |
386 | * | |
387 | * On success, the ipc id is returned. | |
7748dbfa | 388 | */ |
b2d75cdd | 389 | static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids, |
eb66ec44 | 390 | const struct ipc_ops *ops, struct ipc_params *params) |
7748dbfa ND |
391 | { |
392 | struct kern_ipc_perm *ipcp; | |
393 | int flg = params->flg; | |
394 | int err; | |
7748dbfa | 395 | |
3e148c79 ND |
396 | /* |
397 | * Take the lock as a writer since we are potentially going to add | |
398 | * a new entry + read locks are not "upgradable" | |
399 | */ | |
d9a605e4 | 400 | down_write(&ids->rwsem); |
7748dbfa ND |
401 | ipcp = ipc_findkey(ids, params->key); |
402 | if (ipcp == NULL) { | |
403 | /* key not used */ | |
404 | if (!(flg & IPC_CREAT)) | |
405 | err = -ENOENT; | |
7748dbfa ND |
406 | else |
407 | err = ops->getnew(ns, params); | |
408 | } else { | |
409 | /* ipc object has been locked by ipc_findkey() */ | |
410 | ||
411 | if (flg & IPC_CREAT && flg & IPC_EXCL) | |
412 | err = -EEXIST; | |
413 | else { | |
414 | err = 0; | |
415 | if (ops->more_checks) | |
416 | err = ops->more_checks(ipcp, params); | |
417 | if (!err) | |
f4566f04 ND |
418 | /* |
419 | * ipc_check_perms returns the IPC id on | |
420 | * success | |
421 | */ | |
b0e77598 | 422 | err = ipc_check_perms(ns, ipcp, ops, params); |
7748dbfa ND |
423 | } |
424 | ipc_unlock(ipcp); | |
425 | } | |
d9a605e4 | 426 | up_write(&ids->rwsem); |
7748dbfa ND |
427 | |
428 | return err; | |
429 | } | |
430 | ||
0cfb6aee GK |
431 | /** |
432 | * ipc_kht_remove - remove an ipc from the key hashtable | |
433 | * @ids: ipc identifier set | |
434 | * @ipcp: ipc perm structure containing the key to remove | |
435 | * | |
436 | * ipc_ids.rwsem (as a writer) and the spinlock for this ID are held | |
437 | * before this function is called, and remain locked on the exit. | |
438 | */ | |
439 | static void ipc_kht_remove(struct ipc_ids *ids, struct kern_ipc_perm *ipcp) | |
440 | { | |
441 | if (ipcp->key != IPC_PRIVATE) | |
442 | rhashtable_remove_fast(&ids->key_ht, &ipcp->khtnode, | |
443 | ipc_kht_params); | |
444 | } | |
7748dbfa | 445 | |
1da177e4 | 446 | /** |
8001c858 DB |
447 | * ipc_rmid - remove an ipc identifier |
448 | * @ids: ipc identifier set | |
449 | * @ipcp: ipc perm structure containing the identifier to remove | |
1da177e4 | 450 | * |
8001c858 DB |
451 | * ipc_ids.rwsem (as a writer) and the spinlock for this ID are held |
452 | * before this function is called, and remain locked on the exit. | |
1da177e4 | 453 | */ |
7ca7e564 | 454 | void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp) |
1da177e4 | 455 | { |
ce621f5b | 456 | int lid = ipcid_to_idx(ipcp->id); |
7ca7e564 ND |
457 | |
458 | idr_remove(&ids->ipcs_idr, lid); | |
0cfb6aee | 459 | ipc_kht_remove(ids, ipcp); |
1da177e4 | 460 | ids->in_use--; |
72a8ff2f | 461 | ipcp->deleted = true; |
1da177e4 LT |
462 | } |
463 | ||
0cfb6aee GK |
464 | /** |
465 | * ipc_set_key_private - switch the key of an existing ipc to IPC_PRIVATE | |
466 | * @ids: ipc identifier set | |
467 | * @ipcp: ipc perm structure containing the key to modify | |
468 | * | |
469 | * ipc_ids.rwsem (as a writer) and the spinlock for this ID are held | |
470 | * before this function is called, and remain locked on the exit. | |
471 | */ | |
472 | void ipc_set_key_private(struct ipc_ids *ids, struct kern_ipc_perm *ipcp) | |
473 | { | |
474 | ipc_kht_remove(ids, ipcp); | |
475 | ipcp->key = IPC_PRIVATE; | |
476 | } | |
477 | ||
dba4cdd3 | 478 | int ipc_rcu_getref(struct kern_ipc_perm *ptr) |
1da177e4 | 479 | { |
9405c03e | 480 | return refcount_inc_not_zero(&ptr->refcount); |
65f27f38 DH |
481 | } |
482 | ||
dba4cdd3 MS |
483 | void ipc_rcu_putref(struct kern_ipc_perm *ptr, |
484 | void (*func)(struct rcu_head *head)) | |
1da177e4 | 485 | { |
9405c03e | 486 | if (!refcount_dec_and_test(&ptr->refcount)) |
1da177e4 LT |
487 | return; |
488 | ||
dba4cdd3 | 489 | call_rcu(&ptr->rcu, func); |
53dad6d3 DB |
490 | } |
491 | ||
1da177e4 | 492 | /** |
8001c858 DB |
493 | * ipcperms - check ipc permissions |
494 | * @ns: ipc namespace | |
495 | * @ipcp: ipc permission set | |
496 | * @flag: desired permission set | |
1da177e4 | 497 | * |
8001c858 DB |
498 | * Check user, group, other permissions for access |
499 | * to ipc resources. return 0 if allowed | |
b0e77598 | 500 | * |
0e056eb5 | 501 | * @flag will most probably be 0 or ``S_...UGO`` from <linux/stat.h> |
1da177e4 | 502 | */ |
b0e77598 SH |
503 | int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flag) |
504 | { | |
1efdb69b | 505 | kuid_t euid = current_euid(); |
a33e6751 | 506 | int requested_mode, granted_mode; |
1da177e4 | 507 | |
a33e6751 | 508 | audit_ipc_obj(ipcp); |
1da177e4 LT |
509 | requested_mode = (flag >> 6) | (flag >> 3) | flag; |
510 | granted_mode = ipcp->mode; | |
1efdb69b EB |
511 | if (uid_eq(euid, ipcp->cuid) || |
512 | uid_eq(euid, ipcp->uid)) | |
1da177e4 LT |
513 | granted_mode >>= 6; |
514 | else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid)) | |
515 | granted_mode >>= 3; | |
516 | /* is there some bit set in requested_mode but not in granted_mode? */ | |
46c0a8ca | 517 | if ((requested_mode & ~granted_mode & 0007) && |
b0e77598 | 518 | !ns_capable(ns->user_ns, CAP_IPC_OWNER)) |
1da177e4 LT |
519 | return -1; |
520 | ||
521 | return security_ipc_permission(ipcp, flag); | |
522 | } | |
523 | ||
524 | /* | |
525 | * Functions to convert between the kern_ipc_perm structure and the | |
526 | * old/new ipc_perm structures | |
527 | */ | |
528 | ||
529 | /** | |
8001c858 DB |
530 | * kernel_to_ipc64_perm - convert kernel ipc permissions to user |
531 | * @in: kernel permissions | |
532 | * @out: new style ipc permissions | |
1da177e4 | 533 | * |
8001c858 DB |
534 | * Turn the kernel object @in into a set of permissions descriptions |
535 | * for returning to userspace (@out). | |
1da177e4 | 536 | */ |
239521f3 | 537 | void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out) |
1da177e4 LT |
538 | { |
539 | out->key = in->key; | |
1efdb69b EB |
540 | out->uid = from_kuid_munged(current_user_ns(), in->uid); |
541 | out->gid = from_kgid_munged(current_user_ns(), in->gid); | |
542 | out->cuid = from_kuid_munged(current_user_ns(), in->cuid); | |
543 | out->cgid = from_kgid_munged(current_user_ns(), in->cgid); | |
1da177e4 LT |
544 | out->mode = in->mode; |
545 | out->seq = in->seq; | |
546 | } | |
547 | ||
548 | /** | |
8001c858 DB |
549 | * ipc64_perm_to_ipc_perm - convert new ipc permissions to old |
550 | * @in: new style ipc permissions | |
551 | * @out: old style ipc permissions | |
1da177e4 | 552 | * |
8001c858 DB |
553 | * Turn the new style permissions object @in into a compatibility |
554 | * object and store it into the @out pointer. | |
1da177e4 | 555 | */ |
239521f3 | 556 | void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out) |
1da177e4 LT |
557 | { |
558 | out->key = in->key; | |
559 | SET_UID(out->uid, in->uid); | |
560 | SET_GID(out->gid, in->gid); | |
561 | SET_UID(out->cuid, in->cuid); | |
562 | SET_GID(out->cgid, in->cgid); | |
563 | out->mode = in->mode; | |
564 | out->seq = in->seq; | |
565 | } | |
566 | ||
4d2bff5e | 567 | /** |
0cfb6aee | 568 | * ipc_obtain_object_idr |
4d2bff5e DB |
569 | * @ids: ipc identifier set |
570 | * @id: ipc id to look for | |
571 | * | |
572 | * Look for an id in the ipc ids idr and return associated ipc object. | |
573 | * | |
574 | * Call inside the RCU critical section. | |
575 | * The ipc object is *not* locked on exit. | |
576 | */ | |
55b7ae50 | 577 | struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id) |
4d2bff5e DB |
578 | { |
579 | struct kern_ipc_perm *out; | |
580 | int lid = ipcid_to_idx(id); | |
581 | ||
0cfb6aee GK |
582 | if (unlikely(!ids->tables_initialized)) |
583 | return ERR_PTR(-EINVAL); | |
584 | ||
4d2bff5e DB |
585 | out = idr_find(&ids->ipcs_idr, lid); |
586 | if (!out) | |
587 | return ERR_PTR(-EINVAL); | |
588 | ||
589 | return out; | |
590 | } | |
591 | ||
f4566f04 | 592 | /** |
8001c858 DB |
593 | * ipc_lock - lock an ipc structure without rwsem held |
594 | * @ids: ipc identifier set | |
f4566f04 ND |
595 | * @id: ipc id to look for |
596 | * | |
597 | * Look for an id in the ipc ids idr and lock the associated ipc object. | |
598 | * | |
4d2bff5e | 599 | * The ipc object is locked on successful exit. |
f4566f04 | 600 | */ |
7ca7e564 | 601 | struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id) |
1da177e4 | 602 | { |
7ca7e564 | 603 | struct kern_ipc_perm *out; |
1da177e4 LT |
604 | |
605 | rcu_read_lock(); | |
55b7ae50 | 606 | out = ipc_obtain_object_idr(ids, id); |
4d2bff5e | 607 | if (IS_ERR(out)) |
f8b59184 | 608 | goto err; |
7ca7e564 | 609 | |
1da177e4 | 610 | spin_lock(&out->lock); |
4d2bff5e | 611 | |
f8b59184 DB |
612 | /* |
613 | * ipc_rmid() may have already freed the ID while ipc_lock() | |
614 | * was spinning: here verify that the structure is still valid. | |
615 | * Upon races with RMID, return -EIDRM, thus indicating that | |
616 | * the ID points to a removed identifier. | |
1da177e4 | 617 | */ |
72a8ff2f | 618 | if (ipc_valid_object(out)) |
4d2bff5e DB |
619 | return out; |
620 | ||
621 | spin_unlock(&out->lock); | |
f8b59184 DB |
622 | out = ERR_PTR(-EIDRM); |
623 | err: | |
4d2bff5e DB |
624 | rcu_read_unlock(); |
625 | return out; | |
626 | } | |
7ca7e564 | 627 | |
4d2bff5e DB |
628 | /** |
629 | * ipc_obtain_object_check | |
630 | * @ids: ipc identifier set | |
631 | * @id: ipc id to look for | |
632 | * | |
55b7ae50 | 633 | * Similar to ipc_obtain_object_idr() but also checks |
4d2bff5e DB |
634 | * the ipc object reference counter. |
635 | * | |
636 | * Call inside the RCU critical section. | |
637 | * The ipc object is *not* locked on exit. | |
638 | */ | |
639 | struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id) | |
640 | { | |
55b7ae50 | 641 | struct kern_ipc_perm *out = ipc_obtain_object_idr(ids, id); |
4d2bff5e DB |
642 | |
643 | if (IS_ERR(out)) | |
644 | goto out; | |
645 | ||
646 | if (ipc_checkid(out, id)) | |
6157dbbf | 647 | return ERR_PTR(-EINVAL); |
4d2bff5e | 648 | out: |
1da177e4 LT |
649 | return out; |
650 | } | |
651 | ||
b2d75cdd PE |
652 | /** |
653 | * ipcget - Common sys_*get() code | |
da3dae54 | 654 | * @ns: namespace |
8001c858 DB |
655 | * @ids: ipc identifier set |
656 | * @ops: operations to be called on ipc object creation, permission checks | |
657 | * and further checks | |
658 | * @params: the parameters needed by the previous operations. | |
b2d75cdd PE |
659 | * |
660 | * Common routine called by sys_msgget(), sys_semget() and sys_shmget(). | |
661 | */ | |
662 | int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, | |
eb66ec44 | 663 | const struct ipc_ops *ops, struct ipc_params *params) |
b2d75cdd PE |
664 | { |
665 | if (params->key == IPC_PRIVATE) | |
666 | return ipcget_new(ns, ids, ops, params); | |
667 | else | |
668 | return ipcget_public(ns, ids, ops, params); | |
669 | } | |
670 | ||
8f4a3809 | 671 | /** |
8001c858 | 672 | * ipc_update_perm - update the permissions of an ipc object |
8f4a3809 PP |
673 | * @in: the permission given as input. |
674 | * @out: the permission of the ipc to set. | |
675 | */ | |
1efdb69b | 676 | int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out) |
8f4a3809 | 677 | { |
1efdb69b EB |
678 | kuid_t uid = make_kuid(current_user_ns(), in->uid); |
679 | kgid_t gid = make_kgid(current_user_ns(), in->gid); | |
680 | if (!uid_valid(uid) || !gid_valid(gid)) | |
681 | return -EINVAL; | |
682 | ||
683 | out->uid = uid; | |
684 | out->gid = gid; | |
8f4a3809 PP |
685 | out->mode = (out->mode & ~S_IRWXUGO) |
686 | | (in->mode & S_IRWXUGO); | |
1efdb69b EB |
687 | |
688 | return 0; | |
8f4a3809 PP |
689 | } |
690 | ||
a5f75e7f | 691 | /** |
3b1c4ad3 | 692 | * ipcctl_pre_down_nolock - retrieve an ipc and check permissions for some IPC_XXX cmd |
8001c858 | 693 | * @ns: ipc namespace |
a5f75e7f PP |
694 | * @ids: the table of ids where to look for the ipc |
695 | * @id: the id of the ipc to retrieve | |
696 | * @cmd: the cmd to check | |
697 | * @perm: the permission to set | |
698 | * @extra_perm: one extra permission parameter used by msq | |
699 | * | |
700 | * This function does some common audit and permissions check for some IPC_XXX | |
701 | * cmd and is called from semctl_down, shmctl_down and msgctl_down. | |
0e056eb5 | 702 | * It must be called without any lock held and: |
703 | * | |
704 | * - retrieves the ipc with the given id in the given table. | |
705 | * - performs some audit and permission check, depending on the given cmd | |
706 | * - returns a pointer to the ipc object or otherwise, the corresponding | |
707 | * error. | |
7b4cc5d8 | 708 | * |
d9a605e4 | 709 | * Call holding the both the rwsem and the rcu read lock. |
a5f75e7f | 710 | */ |
444d0f62 | 711 | struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns, |
3b1c4ad3 DB |
712 | struct ipc_ids *ids, int id, int cmd, |
713 | struct ipc64_perm *perm, int extra_perm) | |
444d0f62 | 714 | { |
1efdb69b | 715 | kuid_t euid; |
444d0f62 DB |
716 | int err = -EPERM; |
717 | struct kern_ipc_perm *ipcp; | |
a5f75e7f | 718 | |
444d0f62 | 719 | ipcp = ipc_obtain_object_check(ids, id); |
a5f75e7f PP |
720 | if (IS_ERR(ipcp)) { |
721 | err = PTR_ERR(ipcp); | |
7b4cc5d8 | 722 | goto err; |
a5f75e7f PP |
723 | } |
724 | ||
a33e6751 | 725 | audit_ipc_obj(ipcp); |
e816f370 AV |
726 | if (cmd == IPC_SET) |
727 | audit_ipc_set_perm(extra_perm, perm->uid, | |
444d0f62 | 728 | perm->gid, perm->mode); |
414c0708 DH |
729 | |
730 | euid = current_euid(); | |
1efdb69b | 731 | if (uid_eq(euid, ipcp->cuid) || uid_eq(euid, ipcp->uid) || |
b0e77598 | 732 | ns_capable(ns->user_ns, CAP_SYS_ADMIN)) |
7b4cc5d8 DB |
733 | return ipcp; /* successful lookup */ |
734 | err: | |
a5f75e7f PP |
735 | return ERR_PTR(err); |
736 | } | |
737 | ||
c1d7e01d | 738 | #ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION |
1da177e4 LT |
739 | |
740 | ||
741 | /** | |
8001c858 DB |
742 | * ipc_parse_version - ipc call version |
743 | * @cmd: pointer to command | |
1da177e4 | 744 | * |
8001c858 DB |
745 | * Return IPC_64 for new style IPC and IPC_OLD for old style IPC. |
746 | * The @cmd value is turned from an encoding command and version into | |
747 | * just the command code. | |
1da177e4 | 748 | */ |
239521f3 | 749 | int ipc_parse_version(int *cmd) |
1da177e4 LT |
750 | { |
751 | if (*cmd & IPC_64) { | |
752 | *cmd ^= IPC_64; | |
753 | return IPC_64; | |
754 | } else { | |
755 | return IPC_OLD; | |
756 | } | |
757 | } | |
758 | ||
c1d7e01d | 759 | #endif /* CONFIG_ARCH_WANT_IPC_PARSE_VERSION */ |
ae781774 MW |
760 | |
761 | #ifdef CONFIG_PROC_FS | |
bc1fc6d8 EB |
762 | struct ipc_proc_iter { |
763 | struct ipc_namespace *ns; | |
764 | struct ipc_proc_iface *iface; | |
765 | }; | |
766 | ||
7ca7e564 ND |
767 | /* |
768 | * This routine locks the ipc structure found at least at position pos. | |
769 | */ | |
b524b9ad AB |
770 | static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos, |
771 | loff_t *new_pos) | |
ae781774 | 772 | { |
7ca7e564 ND |
773 | struct kern_ipc_perm *ipc; |
774 | int total, id; | |
73ea4130 | 775 | |
7ca7e564 ND |
776 | total = 0; |
777 | for (id = 0; id < pos && total < ids->in_use; id++) { | |
778 | ipc = idr_find(&ids->ipcs_idr, id); | |
779 | if (ipc != NULL) | |
780 | total++; | |
781 | } | |
ae781774 | 782 | |
7ca7e564 ND |
783 | if (total >= ids->in_use) |
784 | return NULL; | |
ae781774 | 785 | |
239521f3 | 786 | for (; pos < IPCMNI; pos++) { |
7ca7e564 ND |
787 | ipc = idr_find(&ids->ipcs_idr, pos); |
788 | if (ipc != NULL) { | |
789 | *new_pos = pos + 1; | |
32a27500 DB |
790 | rcu_read_lock(); |
791 | ipc_lock_object(ipc); | |
ae781774 MW |
792 | return ipc; |
793 | } | |
794 | } | |
795 | ||
796 | /* Out of range - return NULL to terminate iteration */ | |
797 | return NULL; | |
798 | } | |
799 | ||
7ca7e564 ND |
800 | static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos) |
801 | { | |
802 | struct ipc_proc_iter *iter = s->private; | |
803 | struct ipc_proc_iface *iface = iter->iface; | |
804 | struct kern_ipc_perm *ipc = it; | |
805 | ||
806 | /* If we had an ipc id locked before, unlock it */ | |
807 | if (ipc && ipc != SEQ_START_TOKEN) | |
808 | ipc_unlock(ipc); | |
809 | ||
ed2ddbf8 | 810 | return sysvipc_find_ipc(&iter->ns->ids[iface->ids], *pos, pos); |
7ca7e564 ND |
811 | } |
812 | ||
ae781774 | 813 | /* |
f4566f04 ND |
814 | * File positions: pos 0 -> header, pos n -> ipc id = n - 1. |
815 | * SeqFile iterator: iterator value locked ipc pointer or SEQ_TOKEN_START. | |
ae781774 MW |
816 | */ |
817 | static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos) | |
818 | { | |
bc1fc6d8 EB |
819 | struct ipc_proc_iter *iter = s->private; |
820 | struct ipc_proc_iface *iface = iter->iface; | |
73ea4130 KK |
821 | struct ipc_ids *ids; |
822 | ||
ed2ddbf8 | 823 | ids = &iter->ns->ids[iface->ids]; |
ae781774 MW |
824 | |
825 | /* | |
826 | * Take the lock - this will be released by the corresponding | |
827 | * call to stop(). | |
828 | */ | |
d9a605e4 | 829 | down_read(&ids->rwsem); |
ae781774 MW |
830 | |
831 | /* pos < 0 is invalid */ | |
832 | if (*pos < 0) | |
833 | return NULL; | |
834 | ||
835 | /* pos == 0 means header */ | |
836 | if (*pos == 0) | |
837 | return SEQ_START_TOKEN; | |
838 | ||
839 | /* Find the (pos-1)th ipc */ | |
7ca7e564 | 840 | return sysvipc_find_ipc(ids, *pos - 1, pos); |
ae781774 MW |
841 | } |
842 | ||
843 | static void sysvipc_proc_stop(struct seq_file *s, void *it) | |
844 | { | |
845 | struct kern_ipc_perm *ipc = it; | |
bc1fc6d8 EB |
846 | struct ipc_proc_iter *iter = s->private; |
847 | struct ipc_proc_iface *iface = iter->iface; | |
73ea4130 | 848 | struct ipc_ids *ids; |
ae781774 | 849 | |
f4566f04 | 850 | /* If we had a locked structure, release it */ |
ae781774 MW |
851 | if (ipc && ipc != SEQ_START_TOKEN) |
852 | ipc_unlock(ipc); | |
853 | ||
ed2ddbf8 | 854 | ids = &iter->ns->ids[iface->ids]; |
ae781774 | 855 | /* Release the lock we took in start() */ |
d9a605e4 | 856 | up_read(&ids->rwsem); |
ae781774 MW |
857 | } |
858 | ||
859 | static int sysvipc_proc_show(struct seq_file *s, void *it) | |
860 | { | |
bc1fc6d8 EB |
861 | struct ipc_proc_iter *iter = s->private; |
862 | struct ipc_proc_iface *iface = iter->iface; | |
ae781774 | 863 | |
7f032d6e JP |
864 | if (it == SEQ_START_TOKEN) { |
865 | seq_puts(s, iface->header); | |
866 | return 0; | |
867 | } | |
ae781774 MW |
868 | |
869 | return iface->show(s, it); | |
870 | } | |
871 | ||
88e9d34c | 872 | static const struct seq_operations sysvipc_proc_seqops = { |
ae781774 MW |
873 | .start = sysvipc_proc_start, |
874 | .stop = sysvipc_proc_stop, | |
875 | .next = sysvipc_proc_next, | |
876 | .show = sysvipc_proc_show, | |
877 | }; | |
878 | ||
bc1fc6d8 EB |
879 | static int sysvipc_proc_open(struct inode *inode, struct file *file) |
880 | { | |
bc1fc6d8 EB |
881 | struct ipc_proc_iter *iter; |
882 | ||
d66a0520 | 883 | iter = __seq_open_private(file, &sysvipc_proc_seqops, sizeof(*iter)); |
bc1fc6d8 | 884 | if (!iter) |
d66a0520 | 885 | return -ENOMEM; |
bc1fc6d8 | 886 | |
d9dda78b | 887 | iter->iface = PDE_DATA(inode); |
bc1fc6d8 | 888 | iter->ns = get_ipc_ns(current->nsproxy->ipc_ns); |
d66a0520 RJ |
889 | |
890 | return 0; | |
bc1fc6d8 EB |
891 | } |
892 | ||
893 | static int sysvipc_proc_release(struct inode *inode, struct file *file) | |
894 | { | |
895 | struct seq_file *seq = file->private_data; | |
896 | struct ipc_proc_iter *iter = seq->private; | |
897 | put_ipc_ns(iter->ns); | |
898 | return seq_release_private(inode, file); | |
ae781774 MW |
899 | } |
900 | ||
9a32144e | 901 | static const struct file_operations sysvipc_proc_fops = { |
ae781774 MW |
902 | .open = sysvipc_proc_open, |
903 | .read = seq_read, | |
904 | .llseek = seq_lseek, | |
bc1fc6d8 | 905 | .release = sysvipc_proc_release, |
ae781774 MW |
906 | }; |
907 | #endif /* CONFIG_PROC_FS */ |