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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/ipc/util.c | |
3 | * Copyright (C) 1992 Krishna Balasubramanian | |
4 | * | |
5 | * Sep 1997 - Call suser() last after "normal" permission checks so we | |
6 | * get BSD style process accounting right. | |
7 | * Occurs in several places in the IPC code. | |
8 | * Chris Evans, <chris@ferret.lmh.ox.ac.uk> | |
9 | * Nov 1999 - ipc helper functions, unified SMP locking | |
624dffcb | 10 | * Manfred Spraul <manfred@colorfullife.com> |
1da177e4 LT |
11 | * Oct 2002 - One lock per IPC id. RCU ipc_free for lock-free grow_ary(). |
12 | * Mingming Cao <cmm@us.ibm.com> | |
073115d6 SG |
13 | * Mar 2006 - support for audit of ipc object properties |
14 | * Dustin Kirkland <dustin.kirkland@us.ibm.com> | |
73ea4130 KK |
15 | * Jun 2006 - namespaces ssupport |
16 | * OpenVZ, SWsoft Inc. | |
17 | * Pavel Emelianov <xemul@openvz.org> | |
05603c44 DB |
18 | * |
19 | * General sysv ipc locking scheme: | |
18ccee26 DB |
20 | * rcu_read_lock() |
21 | * obtain the ipc object (kern_ipc_perm) by looking up the id in an idr | |
22 | * tree. | |
23 | * - perform initial checks (capabilities, auditing and permission, | |
24 | * etc). | |
25 | * - perform read-only operations, such as STAT, INFO commands. | |
26 | * acquire the ipc lock (kern_ipc_perm.lock) through | |
27 | * ipc_lock_object() | |
28 | * - perform data updates, such as SET, RMID commands and | |
29 | * mechanism-specific operations (semop/semtimedop, | |
30 | * msgsnd/msgrcv, shmat/shmdt). | |
31 | * drop the ipc lock, through ipc_unlock_object(). | |
32 | * rcu_read_unlock() | |
33 | * | |
34 | * The ids->rwsem must be taken when: | |
35 | * - creating, removing and iterating the existing entries in ipc | |
36 | * identifier sets. | |
37 | * - iterating through files under /proc/sysvipc/ | |
38 | * | |
39 | * Note that sems have a special fast path that avoids kern_ipc_perm.lock - | |
40 | * see sem_lock(). | |
1da177e4 LT |
41 | */ |
42 | ||
1da177e4 LT |
43 | #include <linux/mm.h> |
44 | #include <linux/shm.h> | |
45 | #include <linux/init.h> | |
46 | #include <linux/msg.h> | |
1da177e4 LT |
47 | #include <linux/vmalloc.h> |
48 | #include <linux/slab.h> | |
8f68fa2d | 49 | #include <linux/notifier.h> |
c59ede7b | 50 | #include <linux/capability.h> |
1da177e4 LT |
51 | #include <linux/highuid.h> |
52 | #include <linux/security.h> | |
53 | #include <linux/rcupdate.h> | |
54 | #include <linux/workqueue.h> | |
ae781774 MW |
55 | #include <linux/seq_file.h> |
56 | #include <linux/proc_fs.h> | |
073115d6 | 57 | #include <linux/audit.h> |
73ea4130 | 58 | #include <linux/nsproxy.h> |
3e148c79 | 59 | #include <linux/rwsem.h> |
b6b337ad | 60 | #include <linux/memory.h> |
ae5e1b22 | 61 | #include <linux/ipc_namespace.h> |
1da177e4 LT |
62 | |
63 | #include <asm/unistd.h> | |
64 | ||
65 | #include "util.h" | |
66 | ||
ae781774 MW |
67 | struct ipc_proc_iface { |
68 | const char *path; | |
69 | const char *header; | |
73ea4130 | 70 | int ids; |
ae781774 MW |
71 | int (*show)(struct seq_file *, void *); |
72 | }; | |
73 | ||
1da177e4 | 74 | /** |
8001c858 | 75 | * ipc_init - initialise ipc subsystem |
1da177e4 | 76 | * |
8001c858 DB |
77 | * The various sysv ipc resources (semaphores, messages and shared |
78 | * memory) are initialised. | |
79 | * | |
80 | * A callback routine is registered into the memory hotplug notifier | |
81 | * chain: since msgmni scales to lowmem this callback routine will be | |
82 | * called upon successful memory add / remove to recompute msmgni. | |
1da177e4 | 83 | */ |
1da177e4 LT |
84 | static int __init ipc_init(void) |
85 | { | |
0cfb6aee GK |
86 | int err_sem, err_msg; |
87 | ||
88 | err_sem = sem_init(); | |
89 | WARN(err_sem, "ipc: sysv sem_init failed: %d\n", err_sem); | |
90 | err_msg = msg_init(); | |
91 | WARN(err_msg, "ipc: sysv msg_init failed: %d\n", err_msg); | |
1da177e4 | 92 | shm_init(); |
0cfb6aee GK |
93 | |
94 | return err_msg ? err_msg : err_sem; | |
1da177e4 | 95 | } |
6d08a256 | 96 | device_initcall(ipc_init); |
1da177e4 | 97 | |
0cfb6aee GK |
98 | static const struct rhashtable_params ipc_kht_params = { |
99 | .head_offset = offsetof(struct kern_ipc_perm, khtnode), | |
100 | .key_offset = offsetof(struct kern_ipc_perm, key), | |
101 | .key_len = FIELD_SIZEOF(struct kern_ipc_perm, key), | |
102 | .locks_mul = 1, | |
103 | .automatic_shrinking = true, | |
104 | }; | |
105 | ||
1da177e4 | 106 | /** |
8001c858 DB |
107 | * ipc_init_ids - initialise ipc identifiers |
108 | * @ids: ipc identifier set | |
1da177e4 | 109 | * |
8001c858 | 110 | * Set up the sequence range to use for the ipc identifier range (limited |
0cfb6aee | 111 | * below IPCMNI) then initialise the keys hashtable and ids idr. |
1da177e4 | 112 | */ |
0cfb6aee | 113 | int ipc_init_ids(struct ipc_ids *ids) |
1da177e4 | 114 | { |
0cfb6aee | 115 | int err; |
1da177e4 | 116 | ids->in_use = 0; |
1da177e4 | 117 | ids->seq = 0; |
03f59566 | 118 | ids->next_id = -1; |
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 GK |
124 | ids->tables_initialized = true; |
125 | return 0; | |
1da177e4 LT |
126 | } |
127 | ||
ae781774 | 128 | #ifdef CONFIG_PROC_FS |
9a32144e | 129 | static const struct file_operations sysvipc_proc_fops; |
ae781774 | 130 | /** |
8001c858 DB |
131 | * ipc_init_proc_interface - create a proc interface for sysipc types using a seq_file interface. |
132 | * @path: Path in procfs | |
133 | * @header: Banner to be printed at the beginning of the file. | |
134 | * @ids: ipc id table to iterate. | |
135 | * @show: show routine. | |
ae781774 MW |
136 | */ |
137 | void __init ipc_init_proc_interface(const char *path, const char *header, | |
73ea4130 | 138 | int ids, int (*show)(struct seq_file *, void *)) |
ae781774 MW |
139 | { |
140 | struct proc_dir_entry *pde; | |
141 | struct ipc_proc_iface *iface; | |
142 | ||
143 | iface = kmalloc(sizeof(*iface), GFP_KERNEL); | |
144 | if (!iface) | |
145 | return; | |
146 | iface->path = path; | |
147 | iface->header = header; | |
148 | iface->ids = ids; | |
149 | iface->show = show; | |
150 | ||
6a6375db DL |
151 | pde = proc_create_data(path, |
152 | S_IRUGO, /* world readable */ | |
153 | NULL, /* parent dir */ | |
154 | &sysvipc_proc_fops, | |
155 | iface); | |
3ab08fe2 | 156 | if (!pde) |
ae781774 | 157 | kfree(iface); |
ae781774 MW |
158 | } |
159 | #endif | |
160 | ||
1da177e4 | 161 | /** |
8001c858 DB |
162 | * ipc_findkey - find a key in an ipc identifier set |
163 | * @ids: ipc identifier set | |
164 | * @key: key to find | |
46c0a8ca | 165 | * |
8001c858 DB |
166 | * Returns the locked pointer to the ipc structure if found or NULL |
167 | * otherwise. If key is found ipc points to the owning ipc structure | |
168 | * | |
0cfb6aee | 169 | * Called with writer ipc_ids.rwsem held. |
1da177e4 | 170 | */ |
7748dbfa | 171 | static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key) |
1da177e4 | 172 | { |
0cfb6aee | 173 | struct kern_ipc_perm *ipcp = NULL; |
7ca7e564 | 174 | |
0cfb6aee GK |
175 | if (likely(ids->tables_initialized)) |
176 | ipcp = rhashtable_lookup_fast(&ids->key_ht, &key, | |
177 | ipc_kht_params); | |
7ca7e564 | 178 | |
0cfb6aee | 179 | if (ipcp) { |
32a27500 | 180 | rcu_read_lock(); |
0cfb6aee GK |
181 | ipc_lock_object(ipcp); |
182 | return ipcp; | |
1da177e4 | 183 | } |
7ca7e564 ND |
184 | |
185 | return NULL; | |
1da177e4 LT |
186 | } |
187 | ||
7ca7e564 | 188 | /** |
8001c858 DB |
189 | * ipc_get_maxid - get the last assigned id |
190 | * @ids: ipc identifier set | |
7ca7e564 | 191 | * |
8001c858 | 192 | * Called with ipc_ids.rwsem held. |
1da177e4 | 193 | */ |
7ca7e564 ND |
194 | int ipc_get_maxid(struct ipc_ids *ids) |
195 | { | |
196 | struct kern_ipc_perm *ipc; | |
197 | int max_id = -1; | |
198 | int total, id; | |
199 | ||
200 | if (ids->in_use == 0) | |
201 | return -1; | |
1da177e4 | 202 | |
7ca7e564 ND |
203 | if (ids->in_use == IPCMNI) |
204 | return IPCMNI - 1; | |
205 | ||
206 | /* Look for the last assigned id */ | |
207 | total = 0; | |
208 | for (id = 0; id < IPCMNI && total < ids->in_use; id++) { | |
209 | ipc = idr_find(&ids->ipcs_idr, id); | |
210 | if (ipc != NULL) { | |
211 | max_id = id; | |
212 | total++; | |
213 | } | |
214 | } | |
215 | return max_id; | |
1da177e4 LT |
216 | } |
217 | ||
218 | /** | |
8001c858 DB |
219 | * ipc_addid - add an ipc identifier |
220 | * @ids: ipc identifier set | |
221 | * @new: new ipc permission set | |
222 | * @size: limit for the number of used ids | |
1da177e4 | 223 | * |
8001c858 DB |
224 | * Add an entry 'new' to the ipc ids idr. The permissions object is |
225 | * initialised and the first free entry is set up and the id assigned | |
226 | * is returned. The 'new' entry is returned in a locked state on success. | |
227 | * On failure the entry is not locked and a negative err-code is returned. | |
1da177e4 | 228 | * |
8001c858 | 229 | * Called with writer ipc_ids.rwsem held. |
1da177e4 | 230 | */ |
239521f3 | 231 | int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int size) |
1da177e4 | 232 | { |
1efdb69b EB |
233 | kuid_t euid; |
234 | kgid_t egid; | |
0cfb6aee | 235 | int id, err; |
03f59566 | 236 | int next_id = ids->next_id; |
1da177e4 | 237 | |
7ca7e564 ND |
238 | if (size > IPCMNI) |
239 | size = IPCMNI; | |
240 | ||
0cfb6aee | 241 | if (!ids->tables_initialized || ids->in_use >= size) |
283bb7fa | 242 | return -ENOSPC; |
7ca7e564 | 243 | |
54924ea3 TH |
244 | idr_preload(GFP_KERNEL); |
245 | ||
9405c03e | 246 | refcount_set(&new->refcount, 1); |
e00b4ff7 | 247 | spin_lock_init(&new->lock); |
72a8ff2f | 248 | new->deleted = false; |
e00b4ff7 ND |
249 | rcu_read_lock(); |
250 | spin_lock(&new->lock); | |
251 | ||
b9a53227 LT |
252 | current_euid_egid(&euid, &egid); |
253 | new->cuid = new->uid = euid; | |
254 | new->gid = new->cgid = egid; | |
255 | ||
54924ea3 TH |
256 | id = idr_alloc(&ids->ipcs_idr, new, |
257 | (next_id < 0) ? 0 : ipcid_to_idx(next_id), 0, | |
258 | GFP_NOWAIT); | |
259 | idr_preload_end(); | |
0cfb6aee GK |
260 | |
261 | if (id >= 0 && new->key != IPC_PRIVATE) { | |
262 | err = rhashtable_insert_fast(&ids->key_ht, &new->khtnode, | |
263 | ipc_kht_params); | |
264 | if (err < 0) { | |
265 | idr_remove(&ids->ipcs_idr, id); | |
266 | id = err; | |
267 | } | |
268 | } | |
54924ea3 | 269 | if (id < 0) { |
e00b4ff7 ND |
270 | spin_unlock(&new->lock); |
271 | rcu_read_unlock(); | |
54924ea3 | 272 | return id; |
e00b4ff7 | 273 | } |
7ca7e564 | 274 | |
1da177e4 | 275 | ids->in_use++; |
1da177e4 | 276 | |
03f59566 SK |
277 | if (next_id < 0) { |
278 | new->seq = ids->seq++; | |
daf948c7 | 279 | if (ids->seq > IPCID_SEQ_MAX) |
03f59566 SK |
280 | ids->seq = 0; |
281 | } else { | |
282 | new->seq = ipcid_to_seqx(next_id); | |
283 | ids->next_id = -1; | |
284 | } | |
1da177e4 | 285 | |
48dea404 | 286 | new->id = ipc_buildid(id, new->seq); |
1da177e4 LT |
287 | return id; |
288 | } | |
289 | ||
7748dbfa | 290 | /** |
8001c858 DB |
291 | * ipcget_new - create a new ipc object |
292 | * @ns: ipc namespace | |
da3dae54 | 293 | * @ids: ipc identifier set |
8001c858 DB |
294 | * @ops: the actual creation routine to call |
295 | * @params: its parameters | |
296 | * | |
297 | * This routine is called by sys_msgget, sys_semget() and sys_shmget() | |
298 | * when the key is IPC_PRIVATE. | |
7748dbfa | 299 | */ |
b2d75cdd | 300 | static int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids, |
eb66ec44 | 301 | const struct ipc_ops *ops, struct ipc_params *params) |
7748dbfa ND |
302 | { |
303 | int err; | |
7748dbfa | 304 | |
d9a605e4 | 305 | down_write(&ids->rwsem); |
7748dbfa | 306 | err = ops->getnew(ns, params); |
d9a605e4 | 307 | up_write(&ids->rwsem); |
7748dbfa ND |
308 | return err; |
309 | } | |
310 | ||
311 | /** | |
8001c858 DB |
312 | * ipc_check_perms - check security and permissions for an ipc object |
313 | * @ns: ipc namespace | |
314 | * @ipcp: ipc permission set | |
315 | * @ops: the actual security routine to call | |
316 | * @params: its parameters | |
f4566f04 | 317 | * |
8001c858 DB |
318 | * This routine is called by sys_msgget(), sys_semget() and sys_shmget() |
319 | * when the key is not IPC_PRIVATE and that key already exists in the | |
320 | * ds IDR. | |
f4566f04 | 321 | * |
8001c858 | 322 | * On success, the ipc id is returned. |
f4566f04 | 323 | * |
8001c858 | 324 | * It is called with ipc_ids.rwsem and ipcp->lock held. |
7748dbfa | 325 | */ |
b0e77598 SH |
326 | static int ipc_check_perms(struct ipc_namespace *ns, |
327 | struct kern_ipc_perm *ipcp, | |
eb66ec44 | 328 | const struct ipc_ops *ops, |
b0e77598 | 329 | struct ipc_params *params) |
7748dbfa ND |
330 | { |
331 | int err; | |
332 | ||
b0e77598 | 333 | if (ipcperms(ns, ipcp, params->flg)) |
7748dbfa ND |
334 | err = -EACCES; |
335 | else { | |
336 | err = ops->associate(ipcp, params->flg); | |
337 | if (!err) | |
338 | err = ipcp->id; | |
339 | } | |
340 | ||
341 | return err; | |
342 | } | |
343 | ||
344 | /** | |
8001c858 DB |
345 | * ipcget_public - get an ipc object or create a new one |
346 | * @ns: ipc namespace | |
da3dae54 | 347 | * @ids: ipc identifier set |
8001c858 DB |
348 | * @ops: the actual creation routine to call |
349 | * @params: its parameters | |
350 | * | |
351 | * This routine is called by sys_msgget, sys_semget() and sys_shmget() | |
352 | * when the key is not IPC_PRIVATE. | |
353 | * It adds a new entry if the key is not found and does some permission | |
354 | * / security checkings if the key is found. | |
355 | * | |
356 | * On success, the ipc id is returned. | |
7748dbfa | 357 | */ |
b2d75cdd | 358 | static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids, |
eb66ec44 | 359 | const struct ipc_ops *ops, struct ipc_params *params) |
7748dbfa ND |
360 | { |
361 | struct kern_ipc_perm *ipcp; | |
362 | int flg = params->flg; | |
363 | int err; | |
7748dbfa | 364 | |
3e148c79 ND |
365 | /* |
366 | * Take the lock as a writer since we are potentially going to add | |
367 | * a new entry + read locks are not "upgradable" | |
368 | */ | |
d9a605e4 | 369 | down_write(&ids->rwsem); |
7748dbfa ND |
370 | ipcp = ipc_findkey(ids, params->key); |
371 | if (ipcp == NULL) { | |
372 | /* key not used */ | |
373 | if (!(flg & IPC_CREAT)) | |
374 | err = -ENOENT; | |
7748dbfa ND |
375 | else |
376 | err = ops->getnew(ns, params); | |
377 | } else { | |
378 | /* ipc object has been locked by ipc_findkey() */ | |
379 | ||
380 | if (flg & IPC_CREAT && flg & IPC_EXCL) | |
381 | err = -EEXIST; | |
382 | else { | |
383 | err = 0; | |
384 | if (ops->more_checks) | |
385 | err = ops->more_checks(ipcp, params); | |
386 | if (!err) | |
f4566f04 ND |
387 | /* |
388 | * ipc_check_perms returns the IPC id on | |
389 | * success | |
390 | */ | |
b0e77598 | 391 | err = ipc_check_perms(ns, ipcp, ops, params); |
7748dbfa ND |
392 | } |
393 | ipc_unlock(ipcp); | |
394 | } | |
d9a605e4 | 395 | up_write(&ids->rwsem); |
7748dbfa ND |
396 | |
397 | return err; | |
398 | } | |
399 | ||
0cfb6aee GK |
400 | /** |
401 | * ipc_kht_remove - remove an ipc from the key hashtable | |
402 | * @ids: ipc identifier set | |
403 | * @ipcp: ipc perm structure containing the key to remove | |
404 | * | |
405 | * ipc_ids.rwsem (as a writer) and the spinlock for this ID are held | |
406 | * before this function is called, and remain locked on the exit. | |
407 | */ | |
408 | static void ipc_kht_remove(struct ipc_ids *ids, struct kern_ipc_perm *ipcp) | |
409 | { | |
410 | if (ipcp->key != IPC_PRIVATE) | |
411 | rhashtable_remove_fast(&ids->key_ht, &ipcp->khtnode, | |
412 | ipc_kht_params); | |
413 | } | |
7748dbfa | 414 | |
1da177e4 | 415 | /** |
8001c858 DB |
416 | * ipc_rmid - remove an ipc identifier |
417 | * @ids: ipc identifier set | |
418 | * @ipcp: ipc perm structure containing the identifier to remove | |
1da177e4 | 419 | * |
8001c858 DB |
420 | * ipc_ids.rwsem (as a writer) and the spinlock for this ID are held |
421 | * before this function is called, and remain locked on the exit. | |
1da177e4 | 422 | */ |
7ca7e564 | 423 | void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp) |
1da177e4 | 424 | { |
ce621f5b | 425 | int lid = ipcid_to_idx(ipcp->id); |
7ca7e564 ND |
426 | |
427 | idr_remove(&ids->ipcs_idr, lid); | |
0cfb6aee | 428 | ipc_kht_remove(ids, ipcp); |
1da177e4 | 429 | ids->in_use--; |
72a8ff2f | 430 | ipcp->deleted = true; |
1da177e4 LT |
431 | } |
432 | ||
0cfb6aee GK |
433 | /** |
434 | * ipc_set_key_private - switch the key of an existing ipc to IPC_PRIVATE | |
435 | * @ids: ipc identifier set | |
436 | * @ipcp: ipc perm structure containing the key to modify | |
437 | * | |
438 | * ipc_ids.rwsem (as a writer) and the spinlock for this ID are held | |
439 | * before this function is called, and remain locked on the exit. | |
440 | */ | |
441 | void ipc_set_key_private(struct ipc_ids *ids, struct kern_ipc_perm *ipcp) | |
442 | { | |
443 | ipc_kht_remove(ids, ipcp); | |
444 | ipcp->key = IPC_PRIVATE; | |
445 | } | |
446 | ||
dba4cdd3 | 447 | int ipc_rcu_getref(struct kern_ipc_perm *ptr) |
1da177e4 | 448 | { |
9405c03e | 449 | return refcount_inc_not_zero(&ptr->refcount); |
65f27f38 DH |
450 | } |
451 | ||
dba4cdd3 MS |
452 | void ipc_rcu_putref(struct kern_ipc_perm *ptr, |
453 | void (*func)(struct rcu_head *head)) | |
1da177e4 | 454 | { |
9405c03e | 455 | if (!refcount_dec_and_test(&ptr->refcount)) |
1da177e4 LT |
456 | return; |
457 | ||
dba4cdd3 | 458 | call_rcu(&ptr->rcu, func); |
53dad6d3 DB |
459 | } |
460 | ||
1da177e4 | 461 | /** |
8001c858 DB |
462 | * ipcperms - check ipc permissions |
463 | * @ns: ipc namespace | |
464 | * @ipcp: ipc permission set | |
465 | * @flag: desired permission set | |
1da177e4 | 466 | * |
8001c858 DB |
467 | * Check user, group, other permissions for access |
468 | * to ipc resources. return 0 if allowed | |
b0e77598 | 469 | * |
0e056eb5 | 470 | * @flag will most probably be 0 or ``S_...UGO`` from <linux/stat.h> |
1da177e4 | 471 | */ |
b0e77598 SH |
472 | int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flag) |
473 | { | |
1efdb69b | 474 | kuid_t euid = current_euid(); |
a33e6751 | 475 | int requested_mode, granted_mode; |
1da177e4 | 476 | |
a33e6751 | 477 | audit_ipc_obj(ipcp); |
1da177e4 LT |
478 | requested_mode = (flag >> 6) | (flag >> 3) | flag; |
479 | granted_mode = ipcp->mode; | |
1efdb69b EB |
480 | if (uid_eq(euid, ipcp->cuid) || |
481 | uid_eq(euid, ipcp->uid)) | |
1da177e4 LT |
482 | granted_mode >>= 6; |
483 | else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid)) | |
484 | granted_mode >>= 3; | |
485 | /* is there some bit set in requested_mode but not in granted_mode? */ | |
46c0a8ca | 486 | if ((requested_mode & ~granted_mode & 0007) && |
b0e77598 | 487 | !ns_capable(ns->user_ns, CAP_IPC_OWNER)) |
1da177e4 LT |
488 | return -1; |
489 | ||
490 | return security_ipc_permission(ipcp, flag); | |
491 | } | |
492 | ||
493 | /* | |
494 | * Functions to convert between the kern_ipc_perm structure and the | |
495 | * old/new ipc_perm structures | |
496 | */ | |
497 | ||
498 | /** | |
8001c858 DB |
499 | * kernel_to_ipc64_perm - convert kernel ipc permissions to user |
500 | * @in: kernel permissions | |
501 | * @out: new style ipc permissions | |
1da177e4 | 502 | * |
8001c858 DB |
503 | * Turn the kernel object @in into a set of permissions descriptions |
504 | * for returning to userspace (@out). | |
1da177e4 | 505 | */ |
239521f3 | 506 | void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out) |
1da177e4 LT |
507 | { |
508 | out->key = in->key; | |
1efdb69b EB |
509 | out->uid = from_kuid_munged(current_user_ns(), in->uid); |
510 | out->gid = from_kgid_munged(current_user_ns(), in->gid); | |
511 | out->cuid = from_kuid_munged(current_user_ns(), in->cuid); | |
512 | out->cgid = from_kgid_munged(current_user_ns(), in->cgid); | |
1da177e4 LT |
513 | out->mode = in->mode; |
514 | out->seq = in->seq; | |
515 | } | |
516 | ||
517 | /** | |
8001c858 DB |
518 | * ipc64_perm_to_ipc_perm - convert new ipc permissions to old |
519 | * @in: new style ipc permissions | |
520 | * @out: old style ipc permissions | |
1da177e4 | 521 | * |
8001c858 DB |
522 | * Turn the new style permissions object @in into a compatibility |
523 | * object and store it into the @out pointer. | |
1da177e4 | 524 | */ |
239521f3 | 525 | void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out) |
1da177e4 LT |
526 | { |
527 | out->key = in->key; | |
528 | SET_UID(out->uid, in->uid); | |
529 | SET_GID(out->gid, in->gid); | |
530 | SET_UID(out->cuid, in->cuid); | |
531 | SET_GID(out->cgid, in->cgid); | |
532 | out->mode = in->mode; | |
533 | out->seq = in->seq; | |
534 | } | |
535 | ||
4d2bff5e | 536 | /** |
0cfb6aee | 537 | * ipc_obtain_object_idr |
4d2bff5e DB |
538 | * @ids: ipc identifier set |
539 | * @id: ipc id to look for | |
540 | * | |
541 | * Look for an id in the ipc ids idr and return associated ipc object. | |
542 | * | |
543 | * Call inside the RCU critical section. | |
544 | * The ipc object is *not* locked on exit. | |
545 | */ | |
55b7ae50 | 546 | struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id) |
4d2bff5e DB |
547 | { |
548 | struct kern_ipc_perm *out; | |
549 | int lid = ipcid_to_idx(id); | |
550 | ||
0cfb6aee GK |
551 | if (unlikely(!ids->tables_initialized)) |
552 | return ERR_PTR(-EINVAL); | |
553 | ||
4d2bff5e DB |
554 | out = idr_find(&ids->ipcs_idr, lid); |
555 | if (!out) | |
556 | return ERR_PTR(-EINVAL); | |
557 | ||
558 | return out; | |
559 | } | |
560 | ||
f4566f04 | 561 | /** |
8001c858 DB |
562 | * ipc_lock - lock an ipc structure without rwsem held |
563 | * @ids: ipc identifier set | |
f4566f04 ND |
564 | * @id: ipc id to look for |
565 | * | |
566 | * Look for an id in the ipc ids idr and lock the associated ipc object. | |
567 | * | |
4d2bff5e | 568 | * The ipc object is locked on successful exit. |
f4566f04 | 569 | */ |
7ca7e564 | 570 | struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id) |
1da177e4 | 571 | { |
7ca7e564 | 572 | struct kern_ipc_perm *out; |
1da177e4 LT |
573 | |
574 | rcu_read_lock(); | |
55b7ae50 | 575 | out = ipc_obtain_object_idr(ids, id); |
4d2bff5e | 576 | if (IS_ERR(out)) |
f8b59184 | 577 | goto err; |
7ca7e564 | 578 | |
1da177e4 | 579 | spin_lock(&out->lock); |
4d2bff5e | 580 | |
f8b59184 DB |
581 | /* |
582 | * ipc_rmid() may have already freed the ID while ipc_lock() | |
583 | * was spinning: here verify that the structure is still valid. | |
584 | * Upon races with RMID, return -EIDRM, thus indicating that | |
585 | * the ID points to a removed identifier. | |
1da177e4 | 586 | */ |
72a8ff2f | 587 | if (ipc_valid_object(out)) |
4d2bff5e DB |
588 | return out; |
589 | ||
590 | spin_unlock(&out->lock); | |
f8b59184 DB |
591 | out = ERR_PTR(-EIDRM); |
592 | err: | |
4d2bff5e DB |
593 | rcu_read_unlock(); |
594 | return out; | |
595 | } | |
7ca7e564 | 596 | |
4d2bff5e DB |
597 | /** |
598 | * ipc_obtain_object_check | |
599 | * @ids: ipc identifier set | |
600 | * @id: ipc id to look for | |
601 | * | |
55b7ae50 | 602 | * Similar to ipc_obtain_object_idr() but also checks |
4d2bff5e DB |
603 | * the ipc object reference counter. |
604 | * | |
605 | * Call inside the RCU critical section. | |
606 | * The ipc object is *not* locked on exit. | |
607 | */ | |
608 | struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id) | |
609 | { | |
55b7ae50 | 610 | struct kern_ipc_perm *out = ipc_obtain_object_idr(ids, id); |
4d2bff5e DB |
611 | |
612 | if (IS_ERR(out)) | |
613 | goto out; | |
614 | ||
615 | if (ipc_checkid(out, id)) | |
6157dbbf | 616 | return ERR_PTR(-EINVAL); |
4d2bff5e | 617 | out: |
1da177e4 LT |
618 | return out; |
619 | } | |
620 | ||
b2d75cdd PE |
621 | /** |
622 | * ipcget - Common sys_*get() code | |
da3dae54 | 623 | * @ns: namespace |
8001c858 DB |
624 | * @ids: ipc identifier set |
625 | * @ops: operations to be called on ipc object creation, permission checks | |
626 | * and further checks | |
627 | * @params: the parameters needed by the previous operations. | |
b2d75cdd PE |
628 | * |
629 | * Common routine called by sys_msgget(), sys_semget() and sys_shmget(). | |
630 | */ | |
631 | int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, | |
eb66ec44 | 632 | const struct ipc_ops *ops, struct ipc_params *params) |
b2d75cdd PE |
633 | { |
634 | if (params->key == IPC_PRIVATE) | |
635 | return ipcget_new(ns, ids, ops, params); | |
636 | else | |
637 | return ipcget_public(ns, ids, ops, params); | |
638 | } | |
639 | ||
8f4a3809 | 640 | /** |
8001c858 | 641 | * ipc_update_perm - update the permissions of an ipc object |
8f4a3809 PP |
642 | * @in: the permission given as input. |
643 | * @out: the permission of the ipc to set. | |
644 | */ | |
1efdb69b | 645 | int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out) |
8f4a3809 | 646 | { |
1efdb69b EB |
647 | kuid_t uid = make_kuid(current_user_ns(), in->uid); |
648 | kgid_t gid = make_kgid(current_user_ns(), in->gid); | |
649 | if (!uid_valid(uid) || !gid_valid(gid)) | |
650 | return -EINVAL; | |
651 | ||
652 | out->uid = uid; | |
653 | out->gid = gid; | |
8f4a3809 PP |
654 | out->mode = (out->mode & ~S_IRWXUGO) |
655 | | (in->mode & S_IRWXUGO); | |
1efdb69b EB |
656 | |
657 | return 0; | |
8f4a3809 PP |
658 | } |
659 | ||
a5f75e7f | 660 | /** |
3b1c4ad3 | 661 | * ipcctl_pre_down_nolock - retrieve an ipc and check permissions for some IPC_XXX cmd |
8001c858 | 662 | * @ns: ipc namespace |
a5f75e7f PP |
663 | * @ids: the table of ids where to look for the ipc |
664 | * @id: the id of the ipc to retrieve | |
665 | * @cmd: the cmd to check | |
666 | * @perm: the permission to set | |
667 | * @extra_perm: one extra permission parameter used by msq | |
668 | * | |
669 | * This function does some common audit and permissions check for some IPC_XXX | |
670 | * cmd and is called from semctl_down, shmctl_down and msgctl_down. | |
0e056eb5 MCC |
671 | * It must be called without any lock held and: |
672 | * | |
673 | * - retrieves the ipc with the given id in the given table. | |
674 | * - performs some audit and permission check, depending on the given cmd | |
675 | * - returns a pointer to the ipc object or otherwise, the corresponding | |
676 | * error. | |
7b4cc5d8 | 677 | * |
d9a605e4 | 678 | * Call holding the both the rwsem and the rcu read lock. |
a5f75e7f | 679 | */ |
444d0f62 | 680 | struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns, |
3b1c4ad3 DB |
681 | struct ipc_ids *ids, int id, int cmd, |
682 | struct ipc64_perm *perm, int extra_perm) | |
444d0f62 | 683 | { |
1efdb69b | 684 | kuid_t euid; |
444d0f62 DB |
685 | int err = -EPERM; |
686 | struct kern_ipc_perm *ipcp; | |
a5f75e7f | 687 | |
444d0f62 | 688 | ipcp = ipc_obtain_object_check(ids, id); |
a5f75e7f PP |
689 | if (IS_ERR(ipcp)) { |
690 | err = PTR_ERR(ipcp); | |
7b4cc5d8 | 691 | goto err; |
a5f75e7f PP |
692 | } |
693 | ||
a33e6751 | 694 | audit_ipc_obj(ipcp); |
e816f370 AV |
695 | if (cmd == IPC_SET) |
696 | audit_ipc_set_perm(extra_perm, perm->uid, | |
444d0f62 | 697 | perm->gid, perm->mode); |
414c0708 DH |
698 | |
699 | euid = current_euid(); | |
1efdb69b | 700 | if (uid_eq(euid, ipcp->cuid) || uid_eq(euid, ipcp->uid) || |
b0e77598 | 701 | ns_capable(ns->user_ns, CAP_SYS_ADMIN)) |
7b4cc5d8 DB |
702 | return ipcp; /* successful lookup */ |
703 | err: | |
a5f75e7f PP |
704 | return ERR_PTR(err); |
705 | } | |
706 | ||
c1d7e01d | 707 | #ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION |
1da177e4 LT |
708 | |
709 | ||
710 | /** | |
8001c858 DB |
711 | * ipc_parse_version - ipc call version |
712 | * @cmd: pointer to command | |
1da177e4 | 713 | * |
8001c858 DB |
714 | * Return IPC_64 for new style IPC and IPC_OLD for old style IPC. |
715 | * The @cmd value is turned from an encoding command and version into | |
716 | * just the command code. | |
1da177e4 | 717 | */ |
239521f3 | 718 | int ipc_parse_version(int *cmd) |
1da177e4 LT |
719 | { |
720 | if (*cmd & IPC_64) { | |
721 | *cmd ^= IPC_64; | |
722 | return IPC_64; | |
723 | } else { | |
724 | return IPC_OLD; | |
725 | } | |
726 | } | |
727 | ||
c1d7e01d | 728 | #endif /* CONFIG_ARCH_WANT_IPC_PARSE_VERSION */ |
ae781774 MW |
729 | |
730 | #ifdef CONFIG_PROC_FS | |
bc1fc6d8 EB |
731 | struct ipc_proc_iter { |
732 | struct ipc_namespace *ns; | |
733 | struct ipc_proc_iface *iface; | |
734 | }; | |
735 | ||
7ca7e564 ND |
736 | /* |
737 | * This routine locks the ipc structure found at least at position pos. | |
738 | */ | |
b524b9ad AB |
739 | static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos, |
740 | loff_t *new_pos) | |
ae781774 | 741 | { |
7ca7e564 ND |
742 | struct kern_ipc_perm *ipc; |
743 | int total, id; | |
73ea4130 | 744 | |
7ca7e564 ND |
745 | total = 0; |
746 | for (id = 0; id < pos && total < ids->in_use; id++) { | |
747 | ipc = idr_find(&ids->ipcs_idr, id); | |
748 | if (ipc != NULL) | |
749 | total++; | |
750 | } | |
ae781774 | 751 | |
7ca7e564 ND |
752 | if (total >= ids->in_use) |
753 | return NULL; | |
ae781774 | 754 | |
239521f3 | 755 | for (; pos < IPCMNI; pos++) { |
7ca7e564 ND |
756 | ipc = idr_find(&ids->ipcs_idr, pos); |
757 | if (ipc != NULL) { | |
758 | *new_pos = pos + 1; | |
32a27500 DB |
759 | rcu_read_lock(); |
760 | ipc_lock_object(ipc); | |
ae781774 MW |
761 | return ipc; |
762 | } | |
763 | } | |
764 | ||
765 | /* Out of range - return NULL to terminate iteration */ | |
766 | return NULL; | |
767 | } | |
768 | ||
7ca7e564 ND |
769 | static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos) |
770 | { | |
771 | struct ipc_proc_iter *iter = s->private; | |
772 | struct ipc_proc_iface *iface = iter->iface; | |
773 | struct kern_ipc_perm *ipc = it; | |
774 | ||
775 | /* If we had an ipc id locked before, unlock it */ | |
776 | if (ipc && ipc != SEQ_START_TOKEN) | |
777 | ipc_unlock(ipc); | |
778 | ||
ed2ddbf8 | 779 | return sysvipc_find_ipc(&iter->ns->ids[iface->ids], *pos, pos); |
7ca7e564 ND |
780 | } |
781 | ||
ae781774 | 782 | /* |
f4566f04 ND |
783 | * File positions: pos 0 -> header, pos n -> ipc id = n - 1. |
784 | * SeqFile iterator: iterator value locked ipc pointer or SEQ_TOKEN_START. | |
ae781774 MW |
785 | */ |
786 | static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos) | |
787 | { | |
bc1fc6d8 EB |
788 | struct ipc_proc_iter *iter = s->private; |
789 | struct ipc_proc_iface *iface = iter->iface; | |
73ea4130 KK |
790 | struct ipc_ids *ids; |
791 | ||
ed2ddbf8 | 792 | ids = &iter->ns->ids[iface->ids]; |
ae781774 MW |
793 | |
794 | /* | |
795 | * Take the lock - this will be released by the corresponding | |
796 | * call to stop(). | |
797 | */ | |
d9a605e4 | 798 | down_read(&ids->rwsem); |
ae781774 MW |
799 | |
800 | /* pos < 0 is invalid */ | |
801 | if (*pos < 0) | |
802 | return NULL; | |
803 | ||
804 | /* pos == 0 means header */ | |
805 | if (*pos == 0) | |
806 | return SEQ_START_TOKEN; | |
807 | ||
808 | /* Find the (pos-1)th ipc */ | |
7ca7e564 | 809 | return sysvipc_find_ipc(ids, *pos - 1, pos); |
ae781774 MW |
810 | } |
811 | ||
812 | static void sysvipc_proc_stop(struct seq_file *s, void *it) | |
813 | { | |
814 | struct kern_ipc_perm *ipc = it; | |
bc1fc6d8 EB |
815 | struct ipc_proc_iter *iter = s->private; |
816 | struct ipc_proc_iface *iface = iter->iface; | |
73ea4130 | 817 | struct ipc_ids *ids; |
ae781774 | 818 | |
f4566f04 | 819 | /* If we had a locked structure, release it */ |
ae781774 MW |
820 | if (ipc && ipc != SEQ_START_TOKEN) |
821 | ipc_unlock(ipc); | |
822 | ||
ed2ddbf8 | 823 | ids = &iter->ns->ids[iface->ids]; |
ae781774 | 824 | /* Release the lock we took in start() */ |
d9a605e4 | 825 | up_read(&ids->rwsem); |
ae781774 MW |
826 | } |
827 | ||
828 | static int sysvipc_proc_show(struct seq_file *s, void *it) | |
829 | { | |
bc1fc6d8 EB |
830 | struct ipc_proc_iter *iter = s->private; |
831 | struct ipc_proc_iface *iface = iter->iface; | |
ae781774 | 832 | |
7f032d6e JP |
833 | if (it == SEQ_START_TOKEN) { |
834 | seq_puts(s, iface->header); | |
835 | return 0; | |
836 | } | |
ae781774 MW |
837 | |
838 | return iface->show(s, it); | |
839 | } | |
840 | ||
88e9d34c | 841 | static const struct seq_operations sysvipc_proc_seqops = { |
ae781774 MW |
842 | .start = sysvipc_proc_start, |
843 | .stop = sysvipc_proc_stop, | |
844 | .next = sysvipc_proc_next, | |
845 | .show = sysvipc_proc_show, | |
846 | }; | |
847 | ||
bc1fc6d8 EB |
848 | static int sysvipc_proc_open(struct inode *inode, struct file *file) |
849 | { | |
bc1fc6d8 EB |
850 | struct ipc_proc_iter *iter; |
851 | ||
d66a0520 | 852 | iter = __seq_open_private(file, &sysvipc_proc_seqops, sizeof(*iter)); |
bc1fc6d8 | 853 | if (!iter) |
d66a0520 | 854 | return -ENOMEM; |
bc1fc6d8 | 855 | |
d9dda78b | 856 | iter->iface = PDE_DATA(inode); |
bc1fc6d8 | 857 | iter->ns = get_ipc_ns(current->nsproxy->ipc_ns); |
d66a0520 RJ |
858 | |
859 | return 0; | |
bc1fc6d8 EB |
860 | } |
861 | ||
862 | static int sysvipc_proc_release(struct inode *inode, struct file *file) | |
863 | { | |
864 | struct seq_file *seq = file->private_data; | |
865 | struct ipc_proc_iter *iter = seq->private; | |
866 | put_ipc_ns(iter->ns); | |
867 | return seq_release_private(inode, file); | |
ae781774 MW |
868 | } |
869 | ||
9a32144e | 870 | static const struct file_operations sysvipc_proc_fops = { |
ae781774 MW |
871 | .open = sysvipc_proc_open, |
872 | .read = seq_read, | |
873 | .llseek = seq_lseek, | |
bc1fc6d8 | 874 | .release = sysvipc_proc_release, |
ae781774 MW |
875 | }; |
876 | #endif /* CONFIG_PROC_FS */ |