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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> | |
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> |
1da177e4 LT |
35 | |
36 | #include <asm/unistd.h> | |
37 | ||
38 | #include "util.h" | |
39 | ||
ae781774 MW |
40 | struct ipc_proc_iface { |
41 | const char *path; | |
42 | const char *header; | |
73ea4130 | 43 | int ids; |
ae781774 MW |
44 | int (*show)(struct seq_file *, void *); |
45 | }; | |
46 | ||
73ea4130 KK |
47 | struct ipc_namespace init_ipc_ns = { |
48 | .kref = { | |
49 | .refcount = ATOMIC_INIT(2), | |
50 | }, | |
51 | }; | |
52 | ||
73ea4130 KK |
53 | static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns) |
54 | { | |
55 | int err; | |
56 | struct ipc_namespace *ns; | |
57 | ||
58 | err = -ENOMEM; | |
59 | ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL); | |
60 | if (ns == NULL) | |
61 | goto err_mem; | |
62 | ||
63 | err = sem_init_ns(ns); | |
64 | if (err) | |
65 | goto err_sem; | |
66 | err = msg_init_ns(ns); | |
67 | if (err) | |
68 | goto err_msg; | |
69 | err = shm_init_ns(ns); | |
70 | if (err) | |
71 | goto err_shm; | |
72 | ||
73 | kref_init(&ns->kref); | |
74 | return ns; | |
75 | ||
76 | err_shm: | |
77 | msg_exit_ns(ns); | |
78 | err_msg: | |
79 | sem_exit_ns(ns); | |
80 | err_sem: | |
81 | kfree(ns); | |
82 | err_mem: | |
83 | return ERR_PTR(err); | |
84 | } | |
85 | ||
e3222c4e | 86 | struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns) |
73ea4130 | 87 | { |
73ea4130 | 88 | struct ipc_namespace *new_ns; |
73ea4130 | 89 | |
e3222c4e BP |
90 | BUG_ON(!ns); |
91 | get_ipc_ns(ns); | |
73ea4130 KK |
92 | |
93 | if (!(flags & CLONE_NEWIPC)) | |
e3222c4e BP |
94 | return ns; |
95 | ||
96 | new_ns = clone_ipc_ns(ns); | |
97 | ||
98 | put_ipc_ns(ns); | |
99 | return new_ns; | |
73ea4130 KK |
100 | } |
101 | ||
102 | void free_ipc_ns(struct kref *kref) | |
103 | { | |
104 | struct ipc_namespace *ns; | |
105 | ||
106 | ns = container_of(kref, struct ipc_namespace, kref); | |
107 | sem_exit_ns(ns); | |
108 | msg_exit_ns(ns); | |
109 | shm_exit_ns(ns); | |
110 | kfree(ns); | |
111 | } | |
73ea4130 | 112 | |
1da177e4 LT |
113 | /** |
114 | * ipc_init - initialise IPC subsystem | |
115 | * | |
116 | * The various system5 IPC resources (semaphores, messages and shared | |
72fd4a35 | 117 | * memory) are initialised |
1da177e4 LT |
118 | */ |
119 | ||
120 | static int __init ipc_init(void) | |
121 | { | |
122 | sem_init(); | |
123 | msg_init(); | |
124 | shm_init(); | |
125 | return 0; | |
126 | } | |
127 | __initcall(ipc_init); | |
128 | ||
129 | /** | |
130 | * ipc_init_ids - initialise IPC identifiers | |
131 | * @ids: Identifier set | |
1da177e4 | 132 | * |
7ca7e564 ND |
133 | * Set up the sequence range to use for the ipc identifier range (limited |
134 | * below IPCMNI) then initialise the ids idr. | |
1da177e4 LT |
135 | */ |
136 | ||
7ca7e564 | 137 | void ipc_init_ids(struct ipc_ids *ids) |
1da177e4 | 138 | { |
5f921ae9 | 139 | mutex_init(&ids->mutex); |
1da177e4 | 140 | |
1da177e4 | 141 | ids->in_use = 0; |
1da177e4 LT |
142 | ids->seq = 0; |
143 | { | |
144 | int seq_limit = INT_MAX/SEQ_MULTIPLIER; | |
145 | if(seq_limit > USHRT_MAX) | |
146 | ids->seq_max = USHRT_MAX; | |
147 | else | |
148 | ids->seq_max = seq_limit; | |
149 | } | |
150 | ||
7ca7e564 | 151 | idr_init(&ids->ipcs_idr); |
1da177e4 LT |
152 | } |
153 | ||
ae781774 | 154 | #ifdef CONFIG_PROC_FS |
9a32144e | 155 | static const struct file_operations sysvipc_proc_fops; |
ae781774 | 156 | /** |
72fd4a35 | 157 | * ipc_init_proc_interface - Create a proc interface for sysipc types using a seq_file interface. |
ae781774 MW |
158 | * @path: Path in procfs |
159 | * @header: Banner to be printed at the beginning of the file. | |
160 | * @ids: ipc id table to iterate. | |
161 | * @show: show routine. | |
162 | */ | |
163 | void __init ipc_init_proc_interface(const char *path, const char *header, | |
73ea4130 | 164 | int ids, int (*show)(struct seq_file *, void *)) |
ae781774 MW |
165 | { |
166 | struct proc_dir_entry *pde; | |
167 | struct ipc_proc_iface *iface; | |
168 | ||
169 | iface = kmalloc(sizeof(*iface), GFP_KERNEL); | |
170 | if (!iface) | |
171 | return; | |
172 | iface->path = path; | |
173 | iface->header = header; | |
174 | iface->ids = ids; | |
175 | iface->show = show; | |
176 | ||
177 | pde = create_proc_entry(path, | |
178 | S_IRUGO, /* world readable */ | |
179 | NULL /* parent dir */); | |
180 | if (pde) { | |
181 | pde->data = iface; | |
182 | pde->proc_fops = &sysvipc_proc_fops; | |
183 | } else { | |
184 | kfree(iface); | |
185 | } | |
186 | } | |
187 | #endif | |
188 | ||
1da177e4 LT |
189 | /** |
190 | * ipc_findkey - find a key in an ipc identifier set | |
191 | * @ids: Identifier set | |
192 | * @key: The key to find | |
193 | * | |
5f921ae9 | 194 | * Requires ipc_ids.mutex locked. |
7ca7e564 ND |
195 | * Returns the LOCKED pointer to the ipc structure if found or NULL |
196 | * if not. | |
f4566f04 | 197 | * If key is found ipc points to the owning ipc structure |
1da177e4 LT |
198 | */ |
199 | ||
7748dbfa | 200 | static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key) |
1da177e4 | 201 | { |
7ca7e564 ND |
202 | struct kern_ipc_perm *ipc; |
203 | int next_id; | |
204 | int total; | |
1da177e4 | 205 | |
7ca7e564 ND |
206 | for (total = 0, next_id = 0; total < ids->in_use; next_id++) { |
207 | ipc = idr_find(&ids->ipcs_idr, next_id); | |
208 | ||
209 | if (ipc == NULL) | |
1da177e4 | 210 | continue; |
7ca7e564 ND |
211 | |
212 | if (ipc->key != key) { | |
213 | total++; | |
214 | continue; | |
215 | } | |
216 | ||
217 | ipc_lock_by_ptr(ipc); | |
218 | return ipc; | |
1da177e4 | 219 | } |
7ca7e564 ND |
220 | |
221 | return NULL; | |
1da177e4 LT |
222 | } |
223 | ||
7ca7e564 ND |
224 | /** |
225 | * ipc_get_maxid - get the last assigned id | |
226 | * @ids: IPC identifier set | |
227 | * | |
228 | * Called with ipc_ids.mutex held. | |
1da177e4 | 229 | */ |
1da177e4 | 230 | |
7ca7e564 ND |
231 | int ipc_get_maxid(struct ipc_ids *ids) |
232 | { | |
233 | struct kern_ipc_perm *ipc; | |
234 | int max_id = -1; | |
235 | int total, id; | |
236 | ||
237 | if (ids->in_use == 0) | |
238 | return -1; | |
1da177e4 | 239 | |
7ca7e564 ND |
240 | if (ids->in_use == IPCMNI) |
241 | return IPCMNI - 1; | |
242 | ||
243 | /* Look for the last assigned id */ | |
244 | total = 0; | |
245 | for (id = 0; id < IPCMNI && total < ids->in_use; id++) { | |
246 | ipc = idr_find(&ids->ipcs_idr, id); | |
247 | if (ipc != NULL) { | |
248 | max_id = id; | |
249 | total++; | |
250 | } | |
251 | } | |
252 | return max_id; | |
1da177e4 LT |
253 | } |
254 | ||
255 | /** | |
256 | * ipc_addid - add an IPC identifier | |
257 | * @ids: IPC identifier set | |
258 | * @new: new IPC permission set | |
7ca7e564 | 259 | * @size: limit for the number of used ids |
1da177e4 | 260 | * |
f4566f04 | 261 | * Add an entry 'new' to the IPC ids idr. The permissions object is |
1da177e4 | 262 | * initialised and the first free entry is set up and the id assigned |
f4566f04 ND |
263 | * is returned. The 'new' entry is returned in a locked state on success. |
264 | * On failure the entry is not locked and -1 is returned. | |
1da177e4 | 265 | * |
5f921ae9 | 266 | * Called with ipc_ids.mutex held. |
1da177e4 LT |
267 | */ |
268 | ||
269 | int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size) | |
270 | { | |
7ca7e564 | 271 | int id, err; |
1da177e4 | 272 | |
7ca7e564 ND |
273 | if (size > IPCMNI) |
274 | size = IPCMNI; | |
275 | ||
276 | if (ids->in_use >= size) | |
277 | return -1; | |
278 | ||
279 | err = idr_get_new(&ids->ipcs_idr, new, &id); | |
280 | if (err) | |
281 | return -1; | |
282 | ||
1da177e4 | 283 | ids->in_use++; |
1da177e4 LT |
284 | |
285 | new->cuid = new->uid = current->euid; | |
286 | new->gid = new->cgid = current->egid; | |
287 | ||
288 | new->seq = ids->seq++; | |
289 | if(ids->seq > ids->seq_max) | |
290 | ids->seq = 0; | |
291 | ||
292 | spin_lock_init(&new->lock); | |
293 | new->deleted = 0; | |
294 | rcu_read_lock(); | |
295 | spin_lock(&new->lock); | |
1da177e4 LT |
296 | return id; |
297 | } | |
298 | ||
7748dbfa ND |
299 | /** |
300 | * ipcget_new - create a new ipc object | |
301 | * @ns: namespace | |
f4566f04 | 302 | * @ids: IPC identifer set |
7748dbfa ND |
303 | * @ops: the actual creation routine to call |
304 | * @params: its parameters | |
305 | * | |
f4566f04 ND |
306 | * This routine is called by sys_msgget, sys_semget() and sys_shmget() |
307 | * when the key is IPC_PRIVATE. | |
7748dbfa ND |
308 | */ |
309 | int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids, | |
310 | struct ipc_ops *ops, struct ipc_params *params) | |
311 | { | |
312 | int err; | |
313 | ||
314 | err = idr_pre_get(&ids->ipcs_idr, GFP_KERNEL); | |
315 | ||
316 | if (!err) | |
317 | return -ENOMEM; | |
318 | ||
319 | mutex_lock(&ids->mutex); | |
320 | err = ops->getnew(ns, params); | |
321 | mutex_unlock(&ids->mutex); | |
322 | ||
323 | return err; | |
324 | } | |
325 | ||
326 | /** | |
327 | * ipc_check_perms - check security and permissions for an IPC | |
328 | * @ipcp: ipc permission set | |
7748dbfa ND |
329 | * @ops: the actual security routine to call |
330 | * @params: its parameters | |
f4566f04 ND |
331 | * |
332 | * This routine is called by sys_msgget(), sys_semget() and sys_shmget() | |
333 | * when the key is not IPC_PRIVATE and that key already exists in the | |
334 | * ids IDR. | |
335 | * | |
336 | * On success, the IPC id is returned. | |
337 | * | |
338 | * It is called with ipc_ids.mutex and ipcp->lock held. | |
7748dbfa ND |
339 | */ |
340 | static int ipc_check_perms(struct kern_ipc_perm *ipcp, struct ipc_ops *ops, | |
341 | struct ipc_params *params) | |
342 | { | |
343 | int err; | |
344 | ||
345 | if (ipcperms(ipcp, params->flg)) | |
346 | err = -EACCES; | |
347 | else { | |
348 | err = ops->associate(ipcp, params->flg); | |
349 | if (!err) | |
350 | err = ipcp->id; | |
351 | } | |
352 | ||
353 | return err; | |
354 | } | |
355 | ||
356 | /** | |
357 | * ipcget_public - get an ipc object or create a new one | |
358 | * @ns: namespace | |
f4566f04 | 359 | * @ids: IPC identifer set |
7748dbfa ND |
360 | * @ops: the actual creation routine to call |
361 | * @params: its parameters | |
362 | * | |
f4566f04 ND |
363 | * This routine is called by sys_msgget, sys_semget() and sys_shmget() |
364 | * when the key is not IPC_PRIVATE. | |
365 | * It adds a new entry if the key is not found and does some permission | |
366 | * / security checkings if the key is found. | |
367 | * | |
368 | * On success, the ipc id is returned. | |
7748dbfa ND |
369 | */ |
370 | int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids, | |
371 | struct ipc_ops *ops, struct ipc_params *params) | |
372 | { | |
373 | struct kern_ipc_perm *ipcp; | |
374 | int flg = params->flg; | |
375 | int err; | |
376 | ||
377 | err = idr_pre_get(&ids->ipcs_idr, GFP_KERNEL); | |
378 | ||
379 | mutex_lock(&ids->mutex); | |
380 | ipcp = ipc_findkey(ids, params->key); | |
381 | if (ipcp == NULL) { | |
382 | /* key not used */ | |
383 | if (!(flg & IPC_CREAT)) | |
384 | err = -ENOENT; | |
385 | else if (!err) | |
386 | err = -ENOMEM; | |
387 | else | |
388 | err = ops->getnew(ns, params); | |
389 | } else { | |
390 | /* ipc object has been locked by ipc_findkey() */ | |
391 | ||
392 | if (flg & IPC_CREAT && flg & IPC_EXCL) | |
393 | err = -EEXIST; | |
394 | else { | |
395 | err = 0; | |
396 | if (ops->more_checks) | |
397 | err = ops->more_checks(ipcp, params); | |
398 | if (!err) | |
f4566f04 ND |
399 | /* |
400 | * ipc_check_perms returns the IPC id on | |
401 | * success | |
402 | */ | |
7748dbfa ND |
403 | err = ipc_check_perms(ipcp, ops, params); |
404 | } | |
405 | ipc_unlock(ipcp); | |
406 | } | |
407 | mutex_unlock(&ids->mutex); | |
408 | ||
409 | return err; | |
410 | } | |
411 | ||
412 | ||
1da177e4 LT |
413 | /** |
414 | * ipc_rmid - remove an IPC identifier | |
f4566f04 ND |
415 | * @ids: IPC identifier set |
416 | * @ipcp: ipc perm structure containing the identifier to remove | |
1da177e4 | 417 | * |
7ca7e564 ND |
418 | * ipc_ids.mutex and the spinlock for this ID are held before this |
419 | * function is called, and remain locked on the exit. | |
1da177e4 LT |
420 | */ |
421 | ||
7ca7e564 | 422 | void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp) |
1da177e4 | 423 | { |
ce621f5b | 424 | int lid = ipcid_to_idx(ipcp->id); |
7ca7e564 ND |
425 | |
426 | idr_remove(&ids->ipcs_idr, lid); | |
1da177e4 | 427 | |
1da177e4 LT |
428 | ids->in_use--; |
429 | ||
7ca7e564 ND |
430 | ipcp->deleted = 1; |
431 | ||
432 | return; | |
1da177e4 LT |
433 | } |
434 | ||
435 | /** | |
436 | * ipc_alloc - allocate ipc space | |
437 | * @size: size desired | |
438 | * | |
439 | * Allocate memory from the appropriate pools and return a pointer to it. | |
440 | * NULL is returned if the allocation fails | |
441 | */ | |
442 | ||
443 | void* ipc_alloc(int size) | |
444 | { | |
445 | void* out; | |
446 | if(size > PAGE_SIZE) | |
447 | out = vmalloc(size); | |
448 | else | |
449 | out = kmalloc(size, GFP_KERNEL); | |
450 | return out; | |
451 | } | |
452 | ||
453 | /** | |
454 | * ipc_free - free ipc space | |
455 | * @ptr: pointer returned by ipc_alloc | |
456 | * @size: size of block | |
457 | * | |
72fd4a35 | 458 | * Free a block created with ipc_alloc(). The caller must know the size |
1da177e4 LT |
459 | * used in the allocation call. |
460 | */ | |
461 | ||
462 | void ipc_free(void* ptr, int size) | |
463 | { | |
464 | if(size > PAGE_SIZE) | |
465 | vfree(ptr); | |
466 | else | |
467 | kfree(ptr); | |
468 | } | |
469 | ||
470 | /* | |
471 | * rcu allocations: | |
472 | * There are three headers that are prepended to the actual allocation: | |
473 | * - during use: ipc_rcu_hdr. | |
474 | * - during the rcu grace period: ipc_rcu_grace. | |
475 | * - [only if vmalloc]: ipc_rcu_sched. | |
476 | * Their lifetime doesn't overlap, thus the headers share the same memory. | |
477 | * Unlike a normal union, they are right-aligned, thus some container_of | |
478 | * forward/backward casting is necessary: | |
479 | */ | |
480 | struct ipc_rcu_hdr | |
481 | { | |
482 | int refcount; | |
483 | int is_vmalloc; | |
484 | void *data[0]; | |
485 | }; | |
486 | ||
487 | ||
488 | struct ipc_rcu_grace | |
489 | { | |
490 | struct rcu_head rcu; | |
491 | /* "void *" makes sure alignment of following data is sane. */ | |
492 | void *data[0]; | |
493 | }; | |
494 | ||
495 | struct ipc_rcu_sched | |
496 | { | |
497 | struct work_struct work; | |
498 | /* "void *" makes sure alignment of following data is sane. */ | |
499 | void *data[0]; | |
500 | }; | |
501 | ||
502 | #define HDRLEN_KMALLOC (sizeof(struct ipc_rcu_grace) > sizeof(struct ipc_rcu_hdr) ? \ | |
503 | sizeof(struct ipc_rcu_grace) : sizeof(struct ipc_rcu_hdr)) | |
504 | #define HDRLEN_VMALLOC (sizeof(struct ipc_rcu_sched) > HDRLEN_KMALLOC ? \ | |
505 | sizeof(struct ipc_rcu_sched) : HDRLEN_KMALLOC) | |
506 | ||
507 | static inline int rcu_use_vmalloc(int size) | |
508 | { | |
509 | /* Too big for a single page? */ | |
510 | if (HDRLEN_KMALLOC + size > PAGE_SIZE) | |
511 | return 1; | |
512 | return 0; | |
513 | } | |
514 | ||
515 | /** | |
516 | * ipc_rcu_alloc - allocate ipc and rcu space | |
517 | * @size: size desired | |
518 | * | |
519 | * Allocate memory for the rcu header structure + the object. | |
520 | * Returns the pointer to the object. | |
521 | * NULL is returned if the allocation fails. | |
522 | */ | |
523 | ||
524 | void* ipc_rcu_alloc(int size) | |
525 | { | |
526 | void* out; | |
527 | /* | |
528 | * We prepend the allocation with the rcu struct, and | |
529 | * workqueue if necessary (for vmalloc). | |
530 | */ | |
531 | if (rcu_use_vmalloc(size)) { | |
532 | out = vmalloc(HDRLEN_VMALLOC + size); | |
533 | if (out) { | |
534 | out += HDRLEN_VMALLOC; | |
535 | container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 1; | |
536 | container_of(out, struct ipc_rcu_hdr, data)->refcount = 1; | |
537 | } | |
538 | } else { | |
539 | out = kmalloc(HDRLEN_KMALLOC + size, GFP_KERNEL); | |
540 | if (out) { | |
541 | out += HDRLEN_KMALLOC; | |
542 | container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 0; | |
543 | container_of(out, struct ipc_rcu_hdr, data)->refcount = 1; | |
544 | } | |
545 | } | |
546 | ||
547 | return out; | |
548 | } | |
549 | ||
550 | void ipc_rcu_getref(void *ptr) | |
551 | { | |
552 | container_of(ptr, struct ipc_rcu_hdr, data)->refcount++; | |
553 | } | |
554 | ||
65f27f38 DH |
555 | static void ipc_do_vfree(struct work_struct *work) |
556 | { | |
557 | vfree(container_of(work, struct ipc_rcu_sched, work)); | |
558 | } | |
559 | ||
1da177e4 | 560 | /** |
1e5d5331 RD |
561 | * ipc_schedule_free - free ipc + rcu space |
562 | * @head: RCU callback structure for queued work | |
1da177e4 LT |
563 | * |
564 | * Since RCU callback function is called in bh, | |
72fd4a35 | 565 | * we need to defer the vfree to schedule_work(). |
1da177e4 LT |
566 | */ |
567 | static void ipc_schedule_free(struct rcu_head *head) | |
568 | { | |
f4566f04 ND |
569 | struct ipc_rcu_grace *grace; |
570 | struct ipc_rcu_sched *sched; | |
571 | ||
572 | grace = container_of(head, struct ipc_rcu_grace, rcu); | |
573 | sched = container_of(&(grace->data[0]), struct ipc_rcu_sched, | |
574 | data[0]); | |
1da177e4 | 575 | |
65f27f38 | 576 | INIT_WORK(&sched->work, ipc_do_vfree); |
1da177e4 LT |
577 | schedule_work(&sched->work); |
578 | } | |
579 | ||
580 | /** | |
1e5d5331 RD |
581 | * ipc_immediate_free - free ipc + rcu space |
582 | * @head: RCU callback structure that contains pointer to be freed | |
1da177e4 | 583 | * |
72fd4a35 | 584 | * Free from the RCU callback context. |
1da177e4 LT |
585 | */ |
586 | static void ipc_immediate_free(struct rcu_head *head) | |
587 | { | |
588 | struct ipc_rcu_grace *free = | |
589 | container_of(head, struct ipc_rcu_grace, rcu); | |
590 | kfree(free); | |
591 | } | |
592 | ||
593 | void ipc_rcu_putref(void *ptr) | |
594 | { | |
595 | if (--container_of(ptr, struct ipc_rcu_hdr, data)->refcount > 0) | |
596 | return; | |
597 | ||
598 | if (container_of(ptr, struct ipc_rcu_hdr, data)->is_vmalloc) { | |
599 | call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu, | |
600 | ipc_schedule_free); | |
601 | } else { | |
602 | call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu, | |
603 | ipc_immediate_free); | |
604 | } | |
605 | } | |
606 | ||
607 | /** | |
608 | * ipcperms - check IPC permissions | |
609 | * @ipcp: IPC permission set | |
610 | * @flag: desired permission set. | |
611 | * | |
612 | * Check user, group, other permissions for access | |
613 | * to ipc resources. return 0 if allowed | |
614 | */ | |
615 | ||
616 | int ipcperms (struct kern_ipc_perm *ipcp, short flag) | |
617 | { /* flag will most probably be 0 or S_...UGO from <linux/stat.h> */ | |
073115d6 | 618 | int requested_mode, granted_mode, err; |
1da177e4 | 619 | |
073115d6 SG |
620 | if (unlikely((err = audit_ipc_obj(ipcp)))) |
621 | return err; | |
1da177e4 LT |
622 | requested_mode = (flag >> 6) | (flag >> 3) | flag; |
623 | granted_mode = ipcp->mode; | |
624 | if (current->euid == ipcp->cuid || current->euid == ipcp->uid) | |
625 | granted_mode >>= 6; | |
626 | else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid)) | |
627 | granted_mode >>= 3; | |
628 | /* is there some bit set in requested_mode but not in granted_mode? */ | |
629 | if ((requested_mode & ~granted_mode & 0007) && | |
630 | !capable(CAP_IPC_OWNER)) | |
631 | return -1; | |
632 | ||
633 | return security_ipc_permission(ipcp, flag); | |
634 | } | |
635 | ||
636 | /* | |
637 | * Functions to convert between the kern_ipc_perm structure and the | |
638 | * old/new ipc_perm structures | |
639 | */ | |
640 | ||
641 | /** | |
642 | * kernel_to_ipc64_perm - convert kernel ipc permissions to user | |
643 | * @in: kernel permissions | |
644 | * @out: new style IPC permissions | |
645 | * | |
72fd4a35 RD |
646 | * Turn the kernel object @in into a set of permissions descriptions |
647 | * for returning to userspace (@out). | |
1da177e4 LT |
648 | */ |
649 | ||
650 | ||
651 | void kernel_to_ipc64_perm (struct kern_ipc_perm *in, struct ipc64_perm *out) | |
652 | { | |
653 | out->key = in->key; | |
654 | out->uid = in->uid; | |
655 | out->gid = in->gid; | |
656 | out->cuid = in->cuid; | |
657 | out->cgid = in->cgid; | |
658 | out->mode = in->mode; | |
659 | out->seq = in->seq; | |
660 | } | |
661 | ||
662 | /** | |
f4566f04 | 663 | * ipc64_perm_to_ipc_perm - convert new ipc permissions to old |
1da177e4 LT |
664 | * @in: new style IPC permissions |
665 | * @out: old style IPC permissions | |
666 | * | |
72fd4a35 RD |
667 | * Turn the new style permissions object @in into a compatibility |
668 | * object and store it into the @out pointer. | |
1da177e4 LT |
669 | */ |
670 | ||
671 | void ipc64_perm_to_ipc_perm (struct ipc64_perm *in, struct ipc_perm *out) | |
672 | { | |
673 | out->key = in->key; | |
674 | SET_UID(out->uid, in->uid); | |
675 | SET_GID(out->gid, in->gid); | |
676 | SET_UID(out->cuid, in->cuid); | |
677 | SET_GID(out->cgid, in->cgid); | |
678 | out->mode = in->mode; | |
679 | out->seq = in->seq; | |
680 | } | |
681 | ||
f4566f04 ND |
682 | /** |
683 | * ipc_lock - Lock an ipc structure | |
684 | * @ids: IPC identifier set | |
685 | * @id: ipc id to look for | |
686 | * | |
687 | * Look for an id in the ipc ids idr and lock the associated ipc object. | |
688 | * | |
689 | * ipc_ids.mutex is not necessarily held before this function is called, | |
690 | * that's why we enter a RCU read section. | |
691 | * The ipc object is locked on exit. | |
692 | */ | |
693 | ||
7ca7e564 | 694 | struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id) |
1da177e4 | 695 | { |
7ca7e564 | 696 | struct kern_ipc_perm *out; |
ce621f5b | 697 | int lid = ipcid_to_idx(id); |
1da177e4 LT |
698 | |
699 | rcu_read_lock(); | |
7ca7e564 ND |
700 | out = idr_find(&ids->ipcs_idr, lid); |
701 | if (out == NULL) { | |
1da177e4 | 702 | rcu_read_unlock(); |
023a5355 | 703 | return ERR_PTR(-EINVAL); |
1da177e4 | 704 | } |
7ca7e564 | 705 | |
1da177e4 LT |
706 | spin_lock(&out->lock); |
707 | ||
708 | /* ipc_rmid() may have already freed the ID while ipc_lock | |
709 | * was spinning: here verify that the structure is still valid | |
710 | */ | |
711 | if (out->deleted) { | |
712 | spin_unlock(&out->lock); | |
713 | rcu_read_unlock(); | |
023a5355 | 714 | return ERR_PTR(-EINVAL); |
1da177e4 | 715 | } |
7ca7e564 | 716 | |
1da177e4 LT |
717 | return out; |
718 | } | |
719 | ||
1da177e4 LT |
720 | #ifdef __ARCH_WANT_IPC_PARSE_VERSION |
721 | ||
722 | ||
723 | /** | |
724 | * ipc_parse_version - IPC call version | |
725 | * @cmd: pointer to command | |
726 | * | |
727 | * Return IPC_64 for new style IPC and IPC_OLD for old style IPC. | |
72fd4a35 | 728 | * The @cmd value is turned from an encoding command and version into |
1da177e4 LT |
729 | * just the command code. |
730 | */ | |
731 | ||
732 | int ipc_parse_version (int *cmd) | |
733 | { | |
734 | if (*cmd & IPC_64) { | |
735 | *cmd ^= IPC_64; | |
736 | return IPC_64; | |
737 | } else { | |
738 | return IPC_OLD; | |
739 | } | |
740 | } | |
741 | ||
742 | #endif /* __ARCH_WANT_IPC_PARSE_VERSION */ | |
ae781774 MW |
743 | |
744 | #ifdef CONFIG_PROC_FS | |
bc1fc6d8 EB |
745 | struct ipc_proc_iter { |
746 | struct ipc_namespace *ns; | |
747 | struct ipc_proc_iface *iface; | |
748 | }; | |
749 | ||
7ca7e564 ND |
750 | /* |
751 | * This routine locks the ipc structure found at least at position pos. | |
752 | */ | |
753 | struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos, | |
754 | loff_t *new_pos) | |
ae781774 | 755 | { |
7ca7e564 ND |
756 | struct kern_ipc_perm *ipc; |
757 | int total, id; | |
73ea4130 | 758 | |
7ca7e564 ND |
759 | total = 0; |
760 | for (id = 0; id < pos && total < ids->in_use; id++) { | |
761 | ipc = idr_find(&ids->ipcs_idr, id); | |
762 | if (ipc != NULL) | |
763 | total++; | |
764 | } | |
ae781774 | 765 | |
7ca7e564 ND |
766 | if (total >= ids->in_use) |
767 | return NULL; | |
ae781774 | 768 | |
7ca7e564 ND |
769 | for ( ; pos < IPCMNI; pos++) { |
770 | ipc = idr_find(&ids->ipcs_idr, pos); | |
771 | if (ipc != NULL) { | |
772 | *new_pos = pos + 1; | |
773 | ipc_lock_by_ptr(ipc); | |
ae781774 MW |
774 | return ipc; |
775 | } | |
776 | } | |
777 | ||
778 | /* Out of range - return NULL to terminate iteration */ | |
779 | return NULL; | |
780 | } | |
781 | ||
7ca7e564 ND |
782 | static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos) |
783 | { | |
784 | struct ipc_proc_iter *iter = s->private; | |
785 | struct ipc_proc_iface *iface = iter->iface; | |
786 | struct kern_ipc_perm *ipc = it; | |
787 | ||
788 | /* If we had an ipc id locked before, unlock it */ | |
789 | if (ipc && ipc != SEQ_START_TOKEN) | |
790 | ipc_unlock(ipc); | |
791 | ||
792 | return sysvipc_find_ipc(iter->ns->ids[iface->ids], *pos, pos); | |
793 | } | |
794 | ||
ae781774 | 795 | /* |
f4566f04 ND |
796 | * File positions: pos 0 -> header, pos n -> ipc id = n - 1. |
797 | * SeqFile iterator: iterator value locked ipc pointer or SEQ_TOKEN_START. | |
ae781774 MW |
798 | */ |
799 | static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos) | |
800 | { | |
bc1fc6d8 EB |
801 | struct ipc_proc_iter *iter = s->private; |
802 | struct ipc_proc_iface *iface = iter->iface; | |
73ea4130 KK |
803 | struct ipc_ids *ids; |
804 | ||
bc1fc6d8 | 805 | ids = iter->ns->ids[iface->ids]; |
ae781774 MW |
806 | |
807 | /* | |
808 | * Take the lock - this will be released by the corresponding | |
809 | * call to stop(). | |
810 | */ | |
73ea4130 | 811 | mutex_lock(&ids->mutex); |
ae781774 MW |
812 | |
813 | /* pos < 0 is invalid */ | |
814 | if (*pos < 0) | |
815 | return NULL; | |
816 | ||
817 | /* pos == 0 means header */ | |
818 | if (*pos == 0) | |
819 | return SEQ_START_TOKEN; | |
820 | ||
821 | /* Find the (pos-1)th ipc */ | |
7ca7e564 | 822 | return sysvipc_find_ipc(ids, *pos - 1, pos); |
ae781774 MW |
823 | } |
824 | ||
825 | static void sysvipc_proc_stop(struct seq_file *s, void *it) | |
826 | { | |
827 | struct kern_ipc_perm *ipc = it; | |
bc1fc6d8 EB |
828 | struct ipc_proc_iter *iter = s->private; |
829 | struct ipc_proc_iface *iface = iter->iface; | |
73ea4130 | 830 | struct ipc_ids *ids; |
ae781774 | 831 | |
f4566f04 | 832 | /* If we had a locked structure, release it */ |
ae781774 MW |
833 | if (ipc && ipc != SEQ_START_TOKEN) |
834 | ipc_unlock(ipc); | |
835 | ||
bc1fc6d8 | 836 | ids = iter->ns->ids[iface->ids]; |
ae781774 | 837 | /* Release the lock we took in start() */ |
73ea4130 | 838 | mutex_unlock(&ids->mutex); |
ae781774 MW |
839 | } |
840 | ||
841 | static int sysvipc_proc_show(struct seq_file *s, void *it) | |
842 | { | |
bc1fc6d8 EB |
843 | struct ipc_proc_iter *iter = s->private; |
844 | struct ipc_proc_iface *iface = iter->iface; | |
ae781774 MW |
845 | |
846 | if (it == SEQ_START_TOKEN) | |
847 | return seq_puts(s, iface->header); | |
848 | ||
849 | return iface->show(s, it); | |
850 | } | |
851 | ||
852 | static struct seq_operations sysvipc_proc_seqops = { | |
853 | .start = sysvipc_proc_start, | |
854 | .stop = sysvipc_proc_stop, | |
855 | .next = sysvipc_proc_next, | |
856 | .show = sysvipc_proc_show, | |
857 | }; | |
858 | ||
bc1fc6d8 EB |
859 | static int sysvipc_proc_open(struct inode *inode, struct file *file) |
860 | { | |
ae781774 MW |
861 | int ret; |
862 | struct seq_file *seq; | |
bc1fc6d8 EB |
863 | struct ipc_proc_iter *iter; |
864 | ||
865 | ret = -ENOMEM; | |
866 | iter = kmalloc(sizeof(*iter), GFP_KERNEL); | |
867 | if (!iter) | |
868 | goto out; | |
ae781774 MW |
869 | |
870 | ret = seq_open(file, &sysvipc_proc_seqops); | |
bc1fc6d8 EB |
871 | if (ret) |
872 | goto out_kfree; | |
873 | ||
874 | seq = file->private_data; | |
875 | seq->private = iter; | |
876 | ||
877 | iter->iface = PDE(inode)->data; | |
878 | iter->ns = get_ipc_ns(current->nsproxy->ipc_ns); | |
879 | out: | |
ae781774 | 880 | return ret; |
bc1fc6d8 EB |
881 | out_kfree: |
882 | kfree(iter); | |
883 | goto out; | |
884 | } | |
885 | ||
886 | static int sysvipc_proc_release(struct inode *inode, struct file *file) | |
887 | { | |
888 | struct seq_file *seq = file->private_data; | |
889 | struct ipc_proc_iter *iter = seq->private; | |
890 | put_ipc_ns(iter->ns); | |
891 | return seq_release_private(inode, file); | |
ae781774 MW |
892 | } |
893 | ||
9a32144e | 894 | static const struct file_operations sysvipc_proc_fops = { |
ae781774 MW |
895 | .open = sysvipc_proc_open, |
896 | .read = seq_read, | |
897 | .llseek = seq_lseek, | |
bc1fc6d8 | 898 | .release = sysvipc_proc_release, |
ae781774 MW |
899 | }; |
900 | #endif /* CONFIG_PROC_FS */ |