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> | |
1da177e4 LT |
18 | */ |
19 | ||
1da177e4 LT |
20 | #include <linux/mm.h> |
21 | #include <linux/shm.h> | |
22 | #include <linux/init.h> | |
23 | #include <linux/msg.h> | |
1da177e4 LT |
24 | #include <linux/vmalloc.h> |
25 | #include <linux/slab.h> | |
c59ede7b | 26 | #include <linux/capability.h> |
1da177e4 LT |
27 | #include <linux/highuid.h> |
28 | #include <linux/security.h> | |
29 | #include <linux/rcupdate.h> | |
30 | #include <linux/workqueue.h> | |
ae781774 MW |
31 | #include <linux/seq_file.h> |
32 | #include <linux/proc_fs.h> | |
073115d6 | 33 | #include <linux/audit.h> |
73ea4130 | 34 | #include <linux/nsproxy.h> |
3e148c79 | 35 | #include <linux/rwsem.h> |
1da177e4 LT |
36 | |
37 | #include <asm/unistd.h> | |
38 | ||
39 | #include "util.h" | |
40 | ||
ae781774 MW |
41 | struct ipc_proc_iface { |
42 | const char *path; | |
43 | const char *header; | |
73ea4130 | 44 | int ids; |
ae781774 MW |
45 | int (*show)(struct seq_file *, void *); |
46 | }; | |
47 | ||
73ea4130 KK |
48 | struct ipc_namespace init_ipc_ns = { |
49 | .kref = { | |
50 | .refcount = ATOMIC_INIT(2), | |
51 | }, | |
52 | }; | |
53 | ||
73ea4130 KK |
54 | static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns) |
55 | { | |
56 | int err; | |
57 | struct ipc_namespace *ns; | |
58 | ||
59 | err = -ENOMEM; | |
60 | ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL); | |
61 | if (ns == NULL) | |
62 | goto err_mem; | |
63 | ||
64 | err = sem_init_ns(ns); | |
65 | if (err) | |
66 | goto err_sem; | |
67 | err = msg_init_ns(ns); | |
68 | if (err) | |
69 | goto err_msg; | |
70 | err = shm_init_ns(ns); | |
71 | if (err) | |
72 | goto err_shm; | |
73 | ||
74 | kref_init(&ns->kref); | |
75 | return ns; | |
76 | ||
77 | err_shm: | |
78 | msg_exit_ns(ns); | |
79 | err_msg: | |
80 | sem_exit_ns(ns); | |
81 | err_sem: | |
82 | kfree(ns); | |
83 | err_mem: | |
84 | return ERR_PTR(err); | |
85 | } | |
86 | ||
e3222c4e | 87 | struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns) |
73ea4130 | 88 | { |
73ea4130 | 89 | struct ipc_namespace *new_ns; |
73ea4130 | 90 | |
e3222c4e BP |
91 | BUG_ON(!ns); |
92 | get_ipc_ns(ns); | |
73ea4130 KK |
93 | |
94 | if (!(flags & CLONE_NEWIPC)) | |
e3222c4e BP |
95 | return ns; |
96 | ||
97 | new_ns = clone_ipc_ns(ns); | |
98 | ||
99 | put_ipc_ns(ns); | |
100 | return new_ns; | |
73ea4130 KK |
101 | } |
102 | ||
103 | void free_ipc_ns(struct kref *kref) | |
104 | { | |
105 | struct ipc_namespace *ns; | |
106 | ||
107 | ns = container_of(kref, struct ipc_namespace, kref); | |
108 | sem_exit_ns(ns); | |
109 | msg_exit_ns(ns); | |
110 | shm_exit_ns(ns); | |
111 | kfree(ns); | |
112 | } | |
73ea4130 | 113 | |
1da177e4 LT |
114 | /** |
115 | * ipc_init - initialise IPC subsystem | |
116 | * | |
117 | * The various system5 IPC resources (semaphores, messages and shared | |
72fd4a35 | 118 | * memory) are initialised |
1da177e4 LT |
119 | */ |
120 | ||
121 | static int __init ipc_init(void) | |
122 | { | |
123 | sem_init(); | |
124 | msg_init(); | |
125 | shm_init(); | |
126 | return 0; | |
127 | } | |
128 | __initcall(ipc_init); | |
129 | ||
130 | /** | |
131 | * ipc_init_ids - initialise IPC identifiers | |
132 | * @ids: Identifier set | |
1da177e4 | 133 | * |
7ca7e564 ND |
134 | * Set up the sequence range to use for the ipc identifier range (limited |
135 | * below IPCMNI) then initialise the ids idr. | |
1da177e4 LT |
136 | */ |
137 | ||
7ca7e564 | 138 | void ipc_init_ids(struct ipc_ids *ids) |
1da177e4 | 139 | { |
3e148c79 | 140 | init_rwsem(&ids->rw_mutex); |
1da177e4 | 141 | |
1da177e4 | 142 | ids->in_use = 0; |
1da177e4 LT |
143 | ids->seq = 0; |
144 | { | |
145 | int seq_limit = INT_MAX/SEQ_MULTIPLIER; | |
146 | if(seq_limit > USHRT_MAX) | |
147 | ids->seq_max = USHRT_MAX; | |
148 | else | |
149 | ids->seq_max = seq_limit; | |
150 | } | |
151 | ||
7ca7e564 | 152 | idr_init(&ids->ipcs_idr); |
1da177e4 LT |
153 | } |
154 | ||
ae781774 | 155 | #ifdef CONFIG_PROC_FS |
9a32144e | 156 | static const struct file_operations sysvipc_proc_fops; |
ae781774 | 157 | /** |
72fd4a35 | 158 | * ipc_init_proc_interface - Create a proc interface for sysipc types using a seq_file interface. |
ae781774 MW |
159 | * @path: Path in procfs |
160 | * @header: Banner to be printed at the beginning of the file. | |
161 | * @ids: ipc id table to iterate. | |
162 | * @show: show routine. | |
163 | */ | |
164 | void __init ipc_init_proc_interface(const char *path, const char *header, | |
73ea4130 | 165 | int ids, int (*show)(struct seq_file *, void *)) |
ae781774 MW |
166 | { |
167 | struct proc_dir_entry *pde; | |
168 | struct ipc_proc_iface *iface; | |
169 | ||
170 | iface = kmalloc(sizeof(*iface), GFP_KERNEL); | |
171 | if (!iface) | |
172 | return; | |
173 | iface->path = path; | |
174 | iface->header = header; | |
175 | iface->ids = ids; | |
176 | iface->show = show; | |
177 | ||
178 | pde = create_proc_entry(path, | |
179 | S_IRUGO, /* world readable */ | |
180 | NULL /* parent dir */); | |
181 | if (pde) { | |
182 | pde->data = iface; | |
183 | pde->proc_fops = &sysvipc_proc_fops; | |
184 | } else { | |
185 | kfree(iface); | |
186 | } | |
187 | } | |
188 | #endif | |
189 | ||
1da177e4 LT |
190 | /** |
191 | * ipc_findkey - find a key in an ipc identifier set | |
192 | * @ids: Identifier set | |
193 | * @key: The key to find | |
194 | * | |
3e148c79 | 195 | * Requires ipc_ids.rw_mutex locked. |
7ca7e564 ND |
196 | * Returns the LOCKED pointer to the ipc structure if found or NULL |
197 | * if not. | |
f4566f04 | 198 | * If key is found ipc points to the owning ipc structure |
1da177e4 LT |
199 | */ |
200 | ||
7748dbfa | 201 | static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key) |
1da177e4 | 202 | { |
7ca7e564 ND |
203 | struct kern_ipc_perm *ipc; |
204 | int next_id; | |
205 | int total; | |
1da177e4 | 206 | |
7ca7e564 ND |
207 | for (total = 0, next_id = 0; total < ids->in_use; next_id++) { |
208 | ipc = idr_find(&ids->ipcs_idr, next_id); | |
209 | ||
210 | if (ipc == NULL) | |
1da177e4 | 211 | continue; |
7ca7e564 ND |
212 | |
213 | if (ipc->key != key) { | |
214 | total++; | |
215 | continue; | |
216 | } | |
217 | ||
218 | ipc_lock_by_ptr(ipc); | |
219 | return ipc; | |
1da177e4 | 220 | } |
7ca7e564 ND |
221 | |
222 | return NULL; | |
1da177e4 LT |
223 | } |
224 | ||
7ca7e564 ND |
225 | /** |
226 | * ipc_get_maxid - get the last assigned id | |
227 | * @ids: IPC identifier set | |
228 | * | |
3e148c79 | 229 | * Called with ipc_ids.rw_mutex held. |
1da177e4 | 230 | */ |
1da177e4 | 231 | |
7ca7e564 ND |
232 | int ipc_get_maxid(struct ipc_ids *ids) |
233 | { | |
234 | struct kern_ipc_perm *ipc; | |
235 | int max_id = -1; | |
236 | int total, id; | |
237 | ||
238 | if (ids->in_use == 0) | |
239 | return -1; | |
1da177e4 | 240 | |
7ca7e564 ND |
241 | if (ids->in_use == IPCMNI) |
242 | return IPCMNI - 1; | |
243 | ||
244 | /* Look for the last assigned id */ | |
245 | total = 0; | |
246 | for (id = 0; id < IPCMNI && total < ids->in_use; id++) { | |
247 | ipc = idr_find(&ids->ipcs_idr, id); | |
248 | if (ipc != NULL) { | |
249 | max_id = id; | |
250 | total++; | |
251 | } | |
252 | } | |
253 | return max_id; | |
1da177e4 LT |
254 | } |
255 | ||
256 | /** | |
257 | * ipc_addid - add an IPC identifier | |
258 | * @ids: IPC identifier set | |
259 | * @new: new IPC permission set | |
7ca7e564 | 260 | * @size: limit for the number of used ids |
1da177e4 | 261 | * |
f4566f04 | 262 | * Add an entry 'new' to the IPC ids idr. The permissions object is |
1da177e4 | 263 | * initialised and the first free entry is set up and the id assigned |
f4566f04 ND |
264 | * is returned. The 'new' entry is returned in a locked state on success. |
265 | * On failure the entry is not locked and -1 is returned. | |
1da177e4 | 266 | * |
3e148c79 | 267 | * Called with ipc_ids.rw_mutex held as a writer. |
1da177e4 LT |
268 | */ |
269 | ||
270 | int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size) | |
271 | { | |
7ca7e564 | 272 | int id, err; |
1da177e4 | 273 | |
7ca7e564 ND |
274 | if (size > IPCMNI) |
275 | size = IPCMNI; | |
276 | ||
277 | if (ids->in_use >= size) | |
278 | return -1; | |
279 | ||
280 | err = idr_get_new(&ids->ipcs_idr, new, &id); | |
281 | if (err) | |
282 | return -1; | |
283 | ||
1da177e4 | 284 | ids->in_use++; |
1da177e4 LT |
285 | |
286 | new->cuid = new->uid = current->euid; | |
287 | new->gid = new->cgid = current->egid; | |
288 | ||
289 | new->seq = ids->seq++; | |
290 | if(ids->seq > ids->seq_max) | |
291 | ids->seq = 0; | |
292 | ||
293 | spin_lock_init(&new->lock); | |
294 | new->deleted = 0; | |
295 | rcu_read_lock(); | |
296 | spin_lock(&new->lock); | |
1da177e4 LT |
297 | return id; |
298 | } | |
299 | ||
7748dbfa ND |
300 | /** |
301 | * ipcget_new - create a new ipc object | |
302 | * @ns: namespace | |
f4566f04 | 303 | * @ids: IPC identifer set |
7748dbfa ND |
304 | * @ops: the actual creation routine to call |
305 | * @params: its parameters | |
306 | * | |
f4566f04 ND |
307 | * This routine is called by sys_msgget, sys_semget() and sys_shmget() |
308 | * when the key is IPC_PRIVATE. | |
7748dbfa ND |
309 | */ |
310 | int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids, | |
311 | struct ipc_ops *ops, struct ipc_params *params) | |
312 | { | |
313 | int err; | |
314 | ||
315 | err = idr_pre_get(&ids->ipcs_idr, GFP_KERNEL); | |
316 | ||
317 | if (!err) | |
318 | return -ENOMEM; | |
319 | ||
3e148c79 | 320 | down_write(&ids->rw_mutex); |
7748dbfa | 321 | err = ops->getnew(ns, params); |
3e148c79 | 322 | up_write(&ids->rw_mutex); |
7748dbfa ND |
323 | |
324 | return err; | |
325 | } | |
326 | ||
327 | /** | |
328 | * ipc_check_perms - check security and permissions for an IPC | |
329 | * @ipcp: ipc permission set | |
7748dbfa ND |
330 | * @ops: the actual security routine to call |
331 | * @params: its parameters | |
f4566f04 ND |
332 | * |
333 | * This routine is called by sys_msgget(), sys_semget() and sys_shmget() | |
334 | * when the key is not IPC_PRIVATE and that key already exists in the | |
335 | * ids IDR. | |
336 | * | |
337 | * On success, the IPC id is returned. | |
338 | * | |
3e148c79 | 339 | * It is called with ipc_ids.rw_mutex and ipcp->lock held. |
7748dbfa ND |
340 | */ |
341 | static int ipc_check_perms(struct kern_ipc_perm *ipcp, struct ipc_ops *ops, | |
342 | struct ipc_params *params) | |
343 | { | |
344 | int err; | |
345 | ||
346 | if (ipcperms(ipcp, params->flg)) | |
347 | err = -EACCES; | |
348 | else { | |
349 | err = ops->associate(ipcp, params->flg); | |
350 | if (!err) | |
351 | err = ipcp->id; | |
352 | } | |
353 | ||
354 | return err; | |
355 | } | |
356 | ||
357 | /** | |
358 | * ipcget_public - get an ipc object or create a new one | |
359 | * @ns: namespace | |
f4566f04 | 360 | * @ids: IPC identifer set |
7748dbfa ND |
361 | * @ops: the actual creation routine to call |
362 | * @params: its parameters | |
363 | * | |
f4566f04 ND |
364 | * This routine is called by sys_msgget, sys_semget() and sys_shmget() |
365 | * when the key is not IPC_PRIVATE. | |
366 | * It adds a new entry if the key is not found and does some permission | |
367 | * / security checkings if the key is found. | |
368 | * | |
369 | * On success, the ipc id is returned. | |
7748dbfa ND |
370 | */ |
371 | int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids, | |
372 | struct ipc_ops *ops, struct ipc_params *params) | |
373 | { | |
374 | struct kern_ipc_perm *ipcp; | |
375 | int flg = params->flg; | |
376 | int err; | |
377 | ||
378 | err = idr_pre_get(&ids->ipcs_idr, GFP_KERNEL); | |
379 | ||
3e148c79 ND |
380 | /* |
381 | * Take the lock as a writer since we are potentially going to add | |
382 | * a new entry + read locks are not "upgradable" | |
383 | */ | |
384 | down_write(&ids->rw_mutex); | |
7748dbfa ND |
385 | ipcp = ipc_findkey(ids, params->key); |
386 | if (ipcp == NULL) { | |
387 | /* key not used */ | |
388 | if (!(flg & IPC_CREAT)) | |
389 | err = -ENOENT; | |
390 | else if (!err) | |
391 | err = -ENOMEM; | |
392 | else | |
393 | err = ops->getnew(ns, params); | |
394 | } else { | |
395 | /* ipc object has been locked by ipc_findkey() */ | |
396 | ||
397 | if (flg & IPC_CREAT && flg & IPC_EXCL) | |
398 | err = -EEXIST; | |
399 | else { | |
400 | err = 0; | |
401 | if (ops->more_checks) | |
402 | err = ops->more_checks(ipcp, params); | |
403 | if (!err) | |
f4566f04 ND |
404 | /* |
405 | * ipc_check_perms returns the IPC id on | |
406 | * success | |
407 | */ | |
7748dbfa ND |
408 | err = ipc_check_perms(ipcp, ops, params); |
409 | } | |
410 | ipc_unlock(ipcp); | |
411 | } | |
3e148c79 | 412 | up_write(&ids->rw_mutex); |
7748dbfa ND |
413 | |
414 | return err; | |
415 | } | |
416 | ||
417 | ||
1da177e4 LT |
418 | /** |
419 | * ipc_rmid - remove an IPC identifier | |
f4566f04 ND |
420 | * @ids: IPC identifier set |
421 | * @ipcp: ipc perm structure containing the identifier to remove | |
1da177e4 | 422 | * |
3e148c79 ND |
423 | * ipc_ids.rw_mutex (as a writer) and the spinlock for this ID are held |
424 | * before this function is called, and remain locked on the exit. | |
1da177e4 LT |
425 | */ |
426 | ||
7ca7e564 | 427 | void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp) |
1da177e4 | 428 | { |
ce621f5b | 429 | int lid = ipcid_to_idx(ipcp->id); |
7ca7e564 ND |
430 | |
431 | idr_remove(&ids->ipcs_idr, lid); | |
1da177e4 | 432 | |
1da177e4 LT |
433 | ids->in_use--; |
434 | ||
7ca7e564 ND |
435 | ipcp->deleted = 1; |
436 | ||
437 | return; | |
1da177e4 LT |
438 | } |
439 | ||
440 | /** | |
441 | * ipc_alloc - allocate ipc space | |
442 | * @size: size desired | |
443 | * | |
444 | * Allocate memory from the appropriate pools and return a pointer to it. | |
445 | * NULL is returned if the allocation fails | |
446 | */ | |
447 | ||
448 | void* ipc_alloc(int size) | |
449 | { | |
450 | void* out; | |
451 | if(size > PAGE_SIZE) | |
452 | out = vmalloc(size); | |
453 | else | |
454 | out = kmalloc(size, GFP_KERNEL); | |
455 | return out; | |
456 | } | |
457 | ||
458 | /** | |
459 | * ipc_free - free ipc space | |
460 | * @ptr: pointer returned by ipc_alloc | |
461 | * @size: size of block | |
462 | * | |
72fd4a35 | 463 | * Free a block created with ipc_alloc(). The caller must know the size |
1da177e4 LT |
464 | * used in the allocation call. |
465 | */ | |
466 | ||
467 | void ipc_free(void* ptr, int size) | |
468 | { | |
469 | if(size > PAGE_SIZE) | |
470 | vfree(ptr); | |
471 | else | |
472 | kfree(ptr); | |
473 | } | |
474 | ||
475 | /* | |
476 | * rcu allocations: | |
477 | * There are three headers that are prepended to the actual allocation: | |
478 | * - during use: ipc_rcu_hdr. | |
479 | * - during the rcu grace period: ipc_rcu_grace. | |
480 | * - [only if vmalloc]: ipc_rcu_sched. | |
481 | * Their lifetime doesn't overlap, thus the headers share the same memory. | |
482 | * Unlike a normal union, they are right-aligned, thus some container_of | |
483 | * forward/backward casting is necessary: | |
484 | */ | |
485 | struct ipc_rcu_hdr | |
486 | { | |
487 | int refcount; | |
488 | int is_vmalloc; | |
489 | void *data[0]; | |
490 | }; | |
491 | ||
492 | ||
493 | struct ipc_rcu_grace | |
494 | { | |
495 | struct rcu_head rcu; | |
496 | /* "void *" makes sure alignment of following data is sane. */ | |
497 | void *data[0]; | |
498 | }; | |
499 | ||
500 | struct ipc_rcu_sched | |
501 | { | |
502 | struct work_struct work; | |
503 | /* "void *" makes sure alignment of following data is sane. */ | |
504 | void *data[0]; | |
505 | }; | |
506 | ||
507 | #define HDRLEN_KMALLOC (sizeof(struct ipc_rcu_grace) > sizeof(struct ipc_rcu_hdr) ? \ | |
508 | sizeof(struct ipc_rcu_grace) : sizeof(struct ipc_rcu_hdr)) | |
509 | #define HDRLEN_VMALLOC (sizeof(struct ipc_rcu_sched) > HDRLEN_KMALLOC ? \ | |
510 | sizeof(struct ipc_rcu_sched) : HDRLEN_KMALLOC) | |
511 | ||
512 | static inline int rcu_use_vmalloc(int size) | |
513 | { | |
514 | /* Too big for a single page? */ | |
515 | if (HDRLEN_KMALLOC + size > PAGE_SIZE) | |
516 | return 1; | |
517 | return 0; | |
518 | } | |
519 | ||
520 | /** | |
521 | * ipc_rcu_alloc - allocate ipc and rcu space | |
522 | * @size: size desired | |
523 | * | |
524 | * Allocate memory for the rcu header structure + the object. | |
525 | * Returns the pointer to the object. | |
526 | * NULL is returned if the allocation fails. | |
527 | */ | |
528 | ||
529 | void* ipc_rcu_alloc(int size) | |
530 | { | |
531 | void* out; | |
532 | /* | |
533 | * We prepend the allocation with the rcu struct, and | |
534 | * workqueue if necessary (for vmalloc). | |
535 | */ | |
536 | if (rcu_use_vmalloc(size)) { | |
537 | out = vmalloc(HDRLEN_VMALLOC + size); | |
538 | if (out) { | |
539 | out += HDRLEN_VMALLOC; | |
540 | container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 1; | |
541 | container_of(out, struct ipc_rcu_hdr, data)->refcount = 1; | |
542 | } | |
543 | } else { | |
544 | out = kmalloc(HDRLEN_KMALLOC + size, GFP_KERNEL); | |
545 | if (out) { | |
546 | out += HDRLEN_KMALLOC; | |
547 | container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 0; | |
548 | container_of(out, struct ipc_rcu_hdr, data)->refcount = 1; | |
549 | } | |
550 | } | |
551 | ||
552 | return out; | |
553 | } | |
554 | ||
555 | void ipc_rcu_getref(void *ptr) | |
556 | { | |
557 | container_of(ptr, struct ipc_rcu_hdr, data)->refcount++; | |
558 | } | |
559 | ||
65f27f38 DH |
560 | static void ipc_do_vfree(struct work_struct *work) |
561 | { | |
562 | vfree(container_of(work, struct ipc_rcu_sched, work)); | |
563 | } | |
564 | ||
1da177e4 | 565 | /** |
1e5d5331 RD |
566 | * ipc_schedule_free - free ipc + rcu space |
567 | * @head: RCU callback structure for queued work | |
1da177e4 LT |
568 | * |
569 | * Since RCU callback function is called in bh, | |
72fd4a35 | 570 | * we need to defer the vfree to schedule_work(). |
1da177e4 LT |
571 | */ |
572 | static void ipc_schedule_free(struct rcu_head *head) | |
573 | { | |
f4566f04 ND |
574 | struct ipc_rcu_grace *grace; |
575 | struct ipc_rcu_sched *sched; | |
576 | ||
577 | grace = container_of(head, struct ipc_rcu_grace, rcu); | |
578 | sched = container_of(&(grace->data[0]), struct ipc_rcu_sched, | |
579 | data[0]); | |
1da177e4 | 580 | |
65f27f38 | 581 | INIT_WORK(&sched->work, ipc_do_vfree); |
1da177e4 LT |
582 | schedule_work(&sched->work); |
583 | } | |
584 | ||
585 | /** | |
1e5d5331 RD |
586 | * ipc_immediate_free - free ipc + rcu space |
587 | * @head: RCU callback structure that contains pointer to be freed | |
1da177e4 | 588 | * |
72fd4a35 | 589 | * Free from the RCU callback context. |
1da177e4 LT |
590 | */ |
591 | static void ipc_immediate_free(struct rcu_head *head) | |
592 | { | |
593 | struct ipc_rcu_grace *free = | |
594 | container_of(head, struct ipc_rcu_grace, rcu); | |
595 | kfree(free); | |
596 | } | |
597 | ||
598 | void ipc_rcu_putref(void *ptr) | |
599 | { | |
600 | if (--container_of(ptr, struct ipc_rcu_hdr, data)->refcount > 0) | |
601 | return; | |
602 | ||
603 | if (container_of(ptr, struct ipc_rcu_hdr, data)->is_vmalloc) { | |
604 | call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu, | |
605 | ipc_schedule_free); | |
606 | } else { | |
607 | call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu, | |
608 | ipc_immediate_free); | |
609 | } | |
610 | } | |
611 | ||
612 | /** | |
613 | * ipcperms - check IPC permissions | |
614 | * @ipcp: IPC permission set | |
615 | * @flag: desired permission set. | |
616 | * | |
617 | * Check user, group, other permissions for access | |
618 | * to ipc resources. return 0 if allowed | |
619 | */ | |
620 | ||
621 | int ipcperms (struct kern_ipc_perm *ipcp, short flag) | |
622 | { /* flag will most probably be 0 or S_...UGO from <linux/stat.h> */ | |
073115d6 | 623 | int requested_mode, granted_mode, err; |
1da177e4 | 624 | |
073115d6 SG |
625 | if (unlikely((err = audit_ipc_obj(ipcp)))) |
626 | return err; | |
1da177e4 LT |
627 | requested_mode = (flag >> 6) | (flag >> 3) | flag; |
628 | granted_mode = ipcp->mode; | |
629 | if (current->euid == ipcp->cuid || current->euid == ipcp->uid) | |
630 | granted_mode >>= 6; | |
631 | else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid)) | |
632 | granted_mode >>= 3; | |
633 | /* is there some bit set in requested_mode but not in granted_mode? */ | |
634 | if ((requested_mode & ~granted_mode & 0007) && | |
635 | !capable(CAP_IPC_OWNER)) | |
636 | return -1; | |
637 | ||
638 | return security_ipc_permission(ipcp, flag); | |
639 | } | |
640 | ||
641 | /* | |
642 | * Functions to convert between the kern_ipc_perm structure and the | |
643 | * old/new ipc_perm structures | |
644 | */ | |
645 | ||
646 | /** | |
647 | * kernel_to_ipc64_perm - convert kernel ipc permissions to user | |
648 | * @in: kernel permissions | |
649 | * @out: new style IPC permissions | |
650 | * | |
72fd4a35 RD |
651 | * Turn the kernel object @in into a set of permissions descriptions |
652 | * for returning to userspace (@out). | |
1da177e4 LT |
653 | */ |
654 | ||
655 | ||
656 | void kernel_to_ipc64_perm (struct kern_ipc_perm *in, struct ipc64_perm *out) | |
657 | { | |
658 | out->key = in->key; | |
659 | out->uid = in->uid; | |
660 | out->gid = in->gid; | |
661 | out->cuid = in->cuid; | |
662 | out->cgid = in->cgid; | |
663 | out->mode = in->mode; | |
664 | out->seq = in->seq; | |
665 | } | |
666 | ||
667 | /** | |
f4566f04 | 668 | * ipc64_perm_to_ipc_perm - convert new ipc permissions to old |
1da177e4 LT |
669 | * @in: new style IPC permissions |
670 | * @out: old style IPC permissions | |
671 | * | |
72fd4a35 RD |
672 | * Turn the new style permissions object @in into a compatibility |
673 | * object and store it into the @out pointer. | |
1da177e4 LT |
674 | */ |
675 | ||
676 | void ipc64_perm_to_ipc_perm (struct ipc64_perm *in, struct ipc_perm *out) | |
677 | { | |
678 | out->key = in->key; | |
679 | SET_UID(out->uid, in->uid); | |
680 | SET_GID(out->gid, in->gid); | |
681 | SET_UID(out->cuid, in->cuid); | |
682 | SET_GID(out->cgid, in->cgid); | |
683 | out->mode = in->mode; | |
684 | out->seq = in->seq; | |
685 | } | |
686 | ||
f4566f04 | 687 | /** |
3e148c79 | 688 | * ipc_lock - Lock an ipc structure without rw_mutex held |
f4566f04 ND |
689 | * @ids: IPC identifier set |
690 | * @id: ipc id to look for | |
691 | * | |
692 | * Look for an id in the ipc ids idr and lock the associated ipc object. | |
693 | * | |
f4566f04 | 694 | * The ipc object is locked on exit. |
3e148c79 ND |
695 | * |
696 | * This is the routine that should be called when the rw_mutex is not already | |
697 | * held, i.e. idr tree not protected: it protects the idr tree in read mode | |
698 | * during the idr_find(). | |
f4566f04 ND |
699 | */ |
700 | ||
7ca7e564 | 701 | struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id) |
1da177e4 | 702 | { |
7ca7e564 | 703 | struct kern_ipc_perm *out; |
ce621f5b | 704 | int lid = ipcid_to_idx(id); |
1da177e4 | 705 | |
3e148c79 ND |
706 | down_read(&ids->rw_mutex); |
707 | ||
1da177e4 | 708 | rcu_read_lock(); |
7ca7e564 ND |
709 | out = idr_find(&ids->ipcs_idr, lid); |
710 | if (out == NULL) { | |
1da177e4 | 711 | rcu_read_unlock(); |
3e148c79 | 712 | up_read(&ids->rw_mutex); |
023a5355 | 713 | return ERR_PTR(-EINVAL); |
1da177e4 | 714 | } |
7ca7e564 | 715 | |
3e148c79 ND |
716 | up_read(&ids->rw_mutex); |
717 | ||
1da177e4 LT |
718 | spin_lock(&out->lock); |
719 | ||
720 | /* ipc_rmid() may have already freed the ID while ipc_lock | |
721 | * was spinning: here verify that the structure is still valid | |
722 | */ | |
723 | if (out->deleted) { | |
724 | spin_unlock(&out->lock); | |
725 | rcu_read_unlock(); | |
023a5355 | 726 | return ERR_PTR(-EINVAL); |
1da177e4 | 727 | } |
7ca7e564 | 728 | |
1da177e4 LT |
729 | return out; |
730 | } | |
731 | ||
3e148c79 ND |
732 | /** |
733 | * ipc_lock_down - Lock an ipc structure with rw_sem held | |
734 | * @ids: IPC identifier set | |
735 | * @id: ipc id to look for | |
736 | * | |
737 | * Look for an id in the ipc ids idr and lock the associated ipc object. | |
738 | * | |
739 | * The ipc object is locked on exit. | |
740 | * | |
741 | * This is the routine that should be called when the rw_mutex is already | |
742 | * held, i.e. idr tree protected. | |
743 | */ | |
744 | ||
745 | struct kern_ipc_perm *ipc_lock_down(struct ipc_ids *ids, int id) | |
746 | { | |
747 | struct kern_ipc_perm *out; | |
748 | int lid = ipcid_to_idx(id); | |
749 | ||
750 | rcu_read_lock(); | |
751 | out = idr_find(&ids->ipcs_idr, lid); | |
752 | if (out == NULL) { | |
753 | rcu_read_unlock(); | |
754 | return ERR_PTR(-EINVAL); | |
755 | } | |
756 | ||
757 | spin_lock(&out->lock); | |
758 | ||
759 | /* | |
760 | * No need to verify that the structure is still valid since the | |
761 | * rw_mutex is held. | |
762 | */ | |
763 | return out; | |
764 | } | |
765 | ||
1da177e4 LT |
766 | #ifdef __ARCH_WANT_IPC_PARSE_VERSION |
767 | ||
768 | ||
769 | /** | |
770 | * ipc_parse_version - IPC call version | |
771 | * @cmd: pointer to command | |
772 | * | |
773 | * Return IPC_64 for new style IPC and IPC_OLD for old style IPC. | |
72fd4a35 | 774 | * The @cmd value is turned from an encoding command and version into |
1da177e4 LT |
775 | * just the command code. |
776 | */ | |
777 | ||
778 | int ipc_parse_version (int *cmd) | |
779 | { | |
780 | if (*cmd & IPC_64) { | |
781 | *cmd ^= IPC_64; | |
782 | return IPC_64; | |
783 | } else { | |
784 | return IPC_OLD; | |
785 | } | |
786 | } | |
787 | ||
788 | #endif /* __ARCH_WANT_IPC_PARSE_VERSION */ | |
ae781774 MW |
789 | |
790 | #ifdef CONFIG_PROC_FS | |
bc1fc6d8 EB |
791 | struct ipc_proc_iter { |
792 | struct ipc_namespace *ns; | |
793 | struct ipc_proc_iface *iface; | |
794 | }; | |
795 | ||
7ca7e564 ND |
796 | /* |
797 | * This routine locks the ipc structure found at least at position pos. | |
798 | */ | |
799 | struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos, | |
800 | loff_t *new_pos) | |
ae781774 | 801 | { |
7ca7e564 ND |
802 | struct kern_ipc_perm *ipc; |
803 | int total, id; | |
73ea4130 | 804 | |
7ca7e564 ND |
805 | total = 0; |
806 | for (id = 0; id < pos && total < ids->in_use; id++) { | |
807 | ipc = idr_find(&ids->ipcs_idr, id); | |
808 | if (ipc != NULL) | |
809 | total++; | |
810 | } | |
ae781774 | 811 | |
7ca7e564 ND |
812 | if (total >= ids->in_use) |
813 | return NULL; | |
ae781774 | 814 | |
7ca7e564 ND |
815 | for ( ; pos < IPCMNI; pos++) { |
816 | ipc = idr_find(&ids->ipcs_idr, pos); | |
817 | if (ipc != NULL) { | |
818 | *new_pos = pos + 1; | |
819 | ipc_lock_by_ptr(ipc); | |
ae781774 MW |
820 | return ipc; |
821 | } | |
822 | } | |
823 | ||
824 | /* Out of range - return NULL to terminate iteration */ | |
825 | return NULL; | |
826 | } | |
827 | ||
7ca7e564 ND |
828 | static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos) |
829 | { | |
830 | struct ipc_proc_iter *iter = s->private; | |
831 | struct ipc_proc_iface *iface = iter->iface; | |
832 | struct kern_ipc_perm *ipc = it; | |
833 | ||
834 | /* If we had an ipc id locked before, unlock it */ | |
835 | if (ipc && ipc != SEQ_START_TOKEN) | |
836 | ipc_unlock(ipc); | |
837 | ||
838 | return sysvipc_find_ipc(iter->ns->ids[iface->ids], *pos, pos); | |
839 | } | |
840 | ||
ae781774 | 841 | /* |
f4566f04 ND |
842 | * File positions: pos 0 -> header, pos n -> ipc id = n - 1. |
843 | * SeqFile iterator: iterator value locked ipc pointer or SEQ_TOKEN_START. | |
ae781774 MW |
844 | */ |
845 | static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos) | |
846 | { | |
bc1fc6d8 EB |
847 | struct ipc_proc_iter *iter = s->private; |
848 | struct ipc_proc_iface *iface = iter->iface; | |
73ea4130 KK |
849 | struct ipc_ids *ids; |
850 | ||
bc1fc6d8 | 851 | ids = iter->ns->ids[iface->ids]; |
ae781774 MW |
852 | |
853 | /* | |
854 | * Take the lock - this will be released by the corresponding | |
855 | * call to stop(). | |
856 | */ | |
3e148c79 | 857 | down_read(&ids->rw_mutex); |
ae781774 MW |
858 | |
859 | /* pos < 0 is invalid */ | |
860 | if (*pos < 0) | |
861 | return NULL; | |
862 | ||
863 | /* pos == 0 means header */ | |
864 | if (*pos == 0) | |
865 | return SEQ_START_TOKEN; | |
866 | ||
867 | /* Find the (pos-1)th ipc */ | |
7ca7e564 | 868 | return sysvipc_find_ipc(ids, *pos - 1, pos); |
ae781774 MW |
869 | } |
870 | ||
871 | static void sysvipc_proc_stop(struct seq_file *s, void *it) | |
872 | { | |
873 | struct kern_ipc_perm *ipc = it; | |
bc1fc6d8 EB |
874 | struct ipc_proc_iter *iter = s->private; |
875 | struct ipc_proc_iface *iface = iter->iface; | |
73ea4130 | 876 | struct ipc_ids *ids; |
ae781774 | 877 | |
f4566f04 | 878 | /* If we had a locked structure, release it */ |
ae781774 MW |
879 | if (ipc && ipc != SEQ_START_TOKEN) |
880 | ipc_unlock(ipc); | |
881 | ||
bc1fc6d8 | 882 | ids = iter->ns->ids[iface->ids]; |
ae781774 | 883 | /* Release the lock we took in start() */ |
3e148c79 | 884 | up_read(&ids->rw_mutex); |
ae781774 MW |
885 | } |
886 | ||
887 | static int sysvipc_proc_show(struct seq_file *s, void *it) | |
888 | { | |
bc1fc6d8 EB |
889 | struct ipc_proc_iter *iter = s->private; |
890 | struct ipc_proc_iface *iface = iter->iface; | |
ae781774 MW |
891 | |
892 | if (it == SEQ_START_TOKEN) | |
893 | return seq_puts(s, iface->header); | |
894 | ||
895 | return iface->show(s, it); | |
896 | } | |
897 | ||
898 | static struct seq_operations sysvipc_proc_seqops = { | |
899 | .start = sysvipc_proc_start, | |
900 | .stop = sysvipc_proc_stop, | |
901 | .next = sysvipc_proc_next, | |
902 | .show = sysvipc_proc_show, | |
903 | }; | |
904 | ||
bc1fc6d8 EB |
905 | static int sysvipc_proc_open(struct inode *inode, struct file *file) |
906 | { | |
ae781774 MW |
907 | int ret; |
908 | struct seq_file *seq; | |
bc1fc6d8 EB |
909 | struct ipc_proc_iter *iter; |
910 | ||
911 | ret = -ENOMEM; | |
912 | iter = kmalloc(sizeof(*iter), GFP_KERNEL); | |
913 | if (!iter) | |
914 | goto out; | |
ae781774 MW |
915 | |
916 | ret = seq_open(file, &sysvipc_proc_seqops); | |
bc1fc6d8 EB |
917 | if (ret) |
918 | goto out_kfree; | |
919 | ||
920 | seq = file->private_data; | |
921 | seq->private = iter; | |
922 | ||
923 | iter->iface = PDE(inode)->data; | |
924 | iter->ns = get_ipc_ns(current->nsproxy->ipc_ns); | |
925 | out: | |
ae781774 | 926 | return ret; |
bc1fc6d8 EB |
927 | out_kfree: |
928 | kfree(iter); | |
929 | goto out; | |
930 | } | |
931 | ||
932 | static int sysvipc_proc_release(struct inode *inode, struct file *file) | |
933 | { | |
934 | struct seq_file *seq = file->private_data; | |
935 | struct ipc_proc_iter *iter = seq->private; | |
936 | put_ipc_ns(iter->ns); | |
937 | return seq_release_private(inode, file); | |
ae781774 MW |
938 | } |
939 | ||
9a32144e | 940 | static const struct file_operations sysvipc_proc_fops = { |
ae781774 MW |
941 | .open = sysvipc_proc_open, |
942 | .read = seq_read, | |
943 | .llseek = seq_lseek, | |
bc1fc6d8 | 944 | .release = sysvipc_proc_release, |
ae781774 MW |
945 | }; |
946 | #endif /* CONFIG_PROC_FS */ |