Commit | Line | Data |
---|---|---|
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> |
ae5e1b22 | 36 | #include <linux/ipc_namespace.h> |
1da177e4 LT |
37 | |
38 | #include <asm/unistd.h> | |
39 | ||
40 | #include "util.h" | |
41 | ||
ae781774 MW |
42 | struct ipc_proc_iface { |
43 | const char *path; | |
44 | const char *header; | |
73ea4130 | 45 | int ids; |
ae781774 MW |
46 | int (*show)(struct seq_file *, void *); |
47 | }; | |
48 | ||
73ea4130 KK |
49 | struct ipc_namespace init_ipc_ns = { |
50 | .kref = { | |
51 | .refcount = ATOMIC_INIT(2), | |
52 | }, | |
53 | }; | |
54 | ||
1da177e4 LT |
55 | /** |
56 | * ipc_init - initialise IPC subsystem | |
57 | * | |
58 | * The various system5 IPC resources (semaphores, messages and shared | |
72fd4a35 | 59 | * memory) are initialised |
1da177e4 LT |
60 | */ |
61 | ||
62 | static int __init ipc_init(void) | |
63 | { | |
64 | sem_init(); | |
65 | msg_init(); | |
66 | shm_init(); | |
67 | return 0; | |
68 | } | |
69 | __initcall(ipc_init); | |
70 | ||
71 | /** | |
72 | * ipc_init_ids - initialise IPC identifiers | |
73 | * @ids: Identifier set | |
1da177e4 | 74 | * |
7ca7e564 ND |
75 | * Set up the sequence range to use for the ipc identifier range (limited |
76 | * below IPCMNI) then initialise the ids idr. | |
1da177e4 LT |
77 | */ |
78 | ||
7ca7e564 | 79 | void ipc_init_ids(struct ipc_ids *ids) |
1da177e4 | 80 | { |
3e148c79 | 81 | init_rwsem(&ids->rw_mutex); |
1da177e4 | 82 | |
1da177e4 | 83 | ids->in_use = 0; |
1da177e4 LT |
84 | ids->seq = 0; |
85 | { | |
86 | int seq_limit = INT_MAX/SEQ_MULTIPLIER; | |
87 | if(seq_limit > USHRT_MAX) | |
88 | ids->seq_max = USHRT_MAX; | |
89 | else | |
90 | ids->seq_max = seq_limit; | |
91 | } | |
92 | ||
7ca7e564 | 93 | idr_init(&ids->ipcs_idr); |
1da177e4 LT |
94 | } |
95 | ||
ae781774 | 96 | #ifdef CONFIG_PROC_FS |
9a32144e | 97 | static const struct file_operations sysvipc_proc_fops; |
ae781774 | 98 | /** |
72fd4a35 | 99 | * ipc_init_proc_interface - Create a proc interface for sysipc types using a seq_file interface. |
ae781774 MW |
100 | * @path: Path in procfs |
101 | * @header: Banner to be printed at the beginning of the file. | |
102 | * @ids: ipc id table to iterate. | |
103 | * @show: show routine. | |
104 | */ | |
105 | void __init ipc_init_proc_interface(const char *path, const char *header, | |
73ea4130 | 106 | int ids, int (*show)(struct seq_file *, void *)) |
ae781774 MW |
107 | { |
108 | struct proc_dir_entry *pde; | |
109 | struct ipc_proc_iface *iface; | |
110 | ||
111 | iface = kmalloc(sizeof(*iface), GFP_KERNEL); | |
112 | if (!iface) | |
113 | return; | |
114 | iface->path = path; | |
115 | iface->header = header; | |
116 | iface->ids = ids; | |
117 | iface->show = show; | |
118 | ||
119 | pde = create_proc_entry(path, | |
120 | S_IRUGO, /* world readable */ | |
121 | NULL /* parent dir */); | |
122 | if (pde) { | |
123 | pde->data = iface; | |
124 | pde->proc_fops = &sysvipc_proc_fops; | |
125 | } else { | |
126 | kfree(iface); | |
127 | } | |
128 | } | |
129 | #endif | |
130 | ||
1da177e4 LT |
131 | /** |
132 | * ipc_findkey - find a key in an ipc identifier set | |
133 | * @ids: Identifier set | |
134 | * @key: The key to find | |
135 | * | |
3e148c79 | 136 | * Requires ipc_ids.rw_mutex locked. |
7ca7e564 ND |
137 | * Returns the LOCKED pointer to the ipc structure if found or NULL |
138 | * if not. | |
f4566f04 | 139 | * If key is found ipc points to the owning ipc structure |
1da177e4 LT |
140 | */ |
141 | ||
7748dbfa | 142 | static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key) |
1da177e4 | 143 | { |
7ca7e564 ND |
144 | struct kern_ipc_perm *ipc; |
145 | int next_id; | |
146 | int total; | |
1da177e4 | 147 | |
7ca7e564 ND |
148 | for (total = 0, next_id = 0; total < ids->in_use; next_id++) { |
149 | ipc = idr_find(&ids->ipcs_idr, next_id); | |
150 | ||
151 | if (ipc == NULL) | |
1da177e4 | 152 | continue; |
7ca7e564 ND |
153 | |
154 | if (ipc->key != key) { | |
155 | total++; | |
156 | continue; | |
157 | } | |
158 | ||
159 | ipc_lock_by_ptr(ipc); | |
160 | return ipc; | |
1da177e4 | 161 | } |
7ca7e564 ND |
162 | |
163 | return NULL; | |
1da177e4 LT |
164 | } |
165 | ||
7ca7e564 ND |
166 | /** |
167 | * ipc_get_maxid - get the last assigned id | |
168 | * @ids: IPC identifier set | |
169 | * | |
3e148c79 | 170 | * Called with ipc_ids.rw_mutex held. |
1da177e4 | 171 | */ |
1da177e4 | 172 | |
7ca7e564 ND |
173 | int ipc_get_maxid(struct ipc_ids *ids) |
174 | { | |
175 | struct kern_ipc_perm *ipc; | |
176 | int max_id = -1; | |
177 | int total, id; | |
178 | ||
179 | if (ids->in_use == 0) | |
180 | return -1; | |
1da177e4 | 181 | |
7ca7e564 ND |
182 | if (ids->in_use == IPCMNI) |
183 | return IPCMNI - 1; | |
184 | ||
185 | /* Look for the last assigned id */ | |
186 | total = 0; | |
187 | for (id = 0; id < IPCMNI && total < ids->in_use; id++) { | |
188 | ipc = idr_find(&ids->ipcs_idr, id); | |
189 | if (ipc != NULL) { | |
190 | max_id = id; | |
191 | total++; | |
192 | } | |
193 | } | |
194 | return max_id; | |
1da177e4 LT |
195 | } |
196 | ||
197 | /** | |
198 | * ipc_addid - add an IPC identifier | |
199 | * @ids: IPC identifier set | |
200 | * @new: new IPC permission set | |
7ca7e564 | 201 | * @size: limit for the number of used ids |
1da177e4 | 202 | * |
f4566f04 | 203 | * Add an entry 'new' to the IPC ids idr. The permissions object is |
1da177e4 | 204 | * initialised and the first free entry is set up and the id assigned |
f4566f04 | 205 | * is returned. The 'new' entry is returned in a locked state on success. |
283bb7fa | 206 | * On failure the entry is not locked and a negative err-code is returned. |
1da177e4 | 207 | * |
3e148c79 | 208 | * Called with ipc_ids.rw_mutex held as a writer. |
1da177e4 LT |
209 | */ |
210 | ||
211 | int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size) | |
212 | { | |
7ca7e564 | 213 | int id, err; |
1da177e4 | 214 | |
7ca7e564 ND |
215 | if (size > IPCMNI) |
216 | size = IPCMNI; | |
217 | ||
218 | if (ids->in_use >= size) | |
283bb7fa | 219 | return -ENOSPC; |
7ca7e564 ND |
220 | |
221 | err = idr_get_new(&ids->ipcs_idr, new, &id); | |
222 | if (err) | |
283bb7fa | 223 | return err; |
7ca7e564 | 224 | |
1da177e4 | 225 | ids->in_use++; |
1da177e4 LT |
226 | |
227 | new->cuid = new->uid = current->euid; | |
228 | new->gid = new->cgid = current->egid; | |
229 | ||
230 | new->seq = ids->seq++; | |
231 | if(ids->seq > ids->seq_max) | |
232 | ids->seq = 0; | |
233 | ||
234 | spin_lock_init(&new->lock); | |
235 | new->deleted = 0; | |
236 | rcu_read_lock(); | |
237 | spin_lock(&new->lock); | |
1da177e4 LT |
238 | return id; |
239 | } | |
240 | ||
7748dbfa ND |
241 | /** |
242 | * ipcget_new - create a new ipc object | |
243 | * @ns: namespace | |
f4566f04 | 244 | * @ids: IPC identifer set |
7748dbfa ND |
245 | * @ops: the actual creation routine to call |
246 | * @params: its parameters | |
247 | * | |
f4566f04 ND |
248 | * This routine is called by sys_msgget, sys_semget() and sys_shmget() |
249 | * when the key is IPC_PRIVATE. | |
7748dbfa | 250 | */ |
b2d75cdd | 251 | static int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids, |
7748dbfa ND |
252 | struct ipc_ops *ops, struct ipc_params *params) |
253 | { | |
254 | int err; | |
283bb7fa | 255 | retry: |
7748dbfa ND |
256 | err = idr_pre_get(&ids->ipcs_idr, GFP_KERNEL); |
257 | ||
258 | if (!err) | |
259 | return -ENOMEM; | |
260 | ||
3e148c79 | 261 | down_write(&ids->rw_mutex); |
7748dbfa | 262 | err = ops->getnew(ns, params); |
3e148c79 | 263 | up_write(&ids->rw_mutex); |
7748dbfa | 264 | |
283bb7fa PP |
265 | if (err == -EAGAIN) |
266 | goto retry; | |
267 | ||
7748dbfa ND |
268 | return err; |
269 | } | |
270 | ||
271 | /** | |
272 | * ipc_check_perms - check security and permissions for an IPC | |
273 | * @ipcp: ipc permission set | |
7748dbfa ND |
274 | * @ops: the actual security routine to call |
275 | * @params: its parameters | |
f4566f04 ND |
276 | * |
277 | * This routine is called by sys_msgget(), sys_semget() and sys_shmget() | |
278 | * when the key is not IPC_PRIVATE and that key already exists in the | |
279 | * ids IDR. | |
280 | * | |
281 | * On success, the IPC id is returned. | |
282 | * | |
3e148c79 | 283 | * It is called with ipc_ids.rw_mutex and ipcp->lock held. |
7748dbfa ND |
284 | */ |
285 | static int ipc_check_perms(struct kern_ipc_perm *ipcp, struct ipc_ops *ops, | |
286 | struct ipc_params *params) | |
287 | { | |
288 | int err; | |
289 | ||
290 | if (ipcperms(ipcp, params->flg)) | |
291 | err = -EACCES; | |
292 | else { | |
293 | err = ops->associate(ipcp, params->flg); | |
294 | if (!err) | |
295 | err = ipcp->id; | |
296 | } | |
297 | ||
298 | return err; | |
299 | } | |
300 | ||
301 | /** | |
302 | * ipcget_public - get an ipc object or create a new one | |
303 | * @ns: namespace | |
f4566f04 | 304 | * @ids: IPC identifer set |
7748dbfa ND |
305 | * @ops: the actual creation routine to call |
306 | * @params: its parameters | |
307 | * | |
f4566f04 ND |
308 | * This routine is called by sys_msgget, sys_semget() and sys_shmget() |
309 | * when the key is not IPC_PRIVATE. | |
310 | * It adds a new entry if the key is not found and does some permission | |
311 | * / security checkings if the key is found. | |
312 | * | |
313 | * On success, the ipc id is returned. | |
7748dbfa | 314 | */ |
b2d75cdd | 315 | static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids, |
7748dbfa ND |
316 | struct ipc_ops *ops, struct ipc_params *params) |
317 | { | |
318 | struct kern_ipc_perm *ipcp; | |
319 | int flg = params->flg; | |
320 | int err; | |
283bb7fa | 321 | retry: |
7748dbfa ND |
322 | err = idr_pre_get(&ids->ipcs_idr, GFP_KERNEL); |
323 | ||
3e148c79 ND |
324 | /* |
325 | * Take the lock as a writer since we are potentially going to add | |
326 | * a new entry + read locks are not "upgradable" | |
327 | */ | |
328 | down_write(&ids->rw_mutex); | |
7748dbfa ND |
329 | ipcp = ipc_findkey(ids, params->key); |
330 | if (ipcp == NULL) { | |
331 | /* key not used */ | |
332 | if (!(flg & IPC_CREAT)) | |
333 | err = -ENOENT; | |
334 | else if (!err) | |
335 | err = -ENOMEM; | |
336 | else | |
337 | err = ops->getnew(ns, params); | |
338 | } else { | |
339 | /* ipc object has been locked by ipc_findkey() */ | |
340 | ||
341 | if (flg & IPC_CREAT && flg & IPC_EXCL) | |
342 | err = -EEXIST; | |
343 | else { | |
344 | err = 0; | |
345 | if (ops->more_checks) | |
346 | err = ops->more_checks(ipcp, params); | |
347 | if (!err) | |
f4566f04 ND |
348 | /* |
349 | * ipc_check_perms returns the IPC id on | |
350 | * success | |
351 | */ | |
7748dbfa ND |
352 | err = ipc_check_perms(ipcp, ops, params); |
353 | } | |
354 | ipc_unlock(ipcp); | |
355 | } | |
3e148c79 | 356 | up_write(&ids->rw_mutex); |
7748dbfa | 357 | |
283bb7fa PP |
358 | if (err == -EAGAIN) |
359 | goto retry; | |
360 | ||
7748dbfa ND |
361 | return err; |
362 | } | |
363 | ||
364 | ||
1da177e4 LT |
365 | /** |
366 | * ipc_rmid - remove an IPC identifier | |
f4566f04 ND |
367 | * @ids: IPC identifier set |
368 | * @ipcp: ipc perm structure containing the identifier to remove | |
1da177e4 | 369 | * |
3e148c79 ND |
370 | * ipc_ids.rw_mutex (as a writer) and the spinlock for this ID are held |
371 | * before this function is called, and remain locked on the exit. | |
1da177e4 LT |
372 | */ |
373 | ||
7ca7e564 | 374 | void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp) |
1da177e4 | 375 | { |
ce621f5b | 376 | int lid = ipcid_to_idx(ipcp->id); |
7ca7e564 ND |
377 | |
378 | idr_remove(&ids->ipcs_idr, lid); | |
1da177e4 | 379 | |
1da177e4 LT |
380 | ids->in_use--; |
381 | ||
7ca7e564 ND |
382 | ipcp->deleted = 1; |
383 | ||
384 | return; | |
1da177e4 LT |
385 | } |
386 | ||
387 | /** | |
388 | * ipc_alloc - allocate ipc space | |
389 | * @size: size desired | |
390 | * | |
391 | * Allocate memory from the appropriate pools and return a pointer to it. | |
392 | * NULL is returned if the allocation fails | |
393 | */ | |
394 | ||
395 | void* ipc_alloc(int size) | |
396 | { | |
397 | void* out; | |
398 | if(size > PAGE_SIZE) | |
399 | out = vmalloc(size); | |
400 | else | |
401 | out = kmalloc(size, GFP_KERNEL); | |
402 | return out; | |
403 | } | |
404 | ||
405 | /** | |
406 | * ipc_free - free ipc space | |
407 | * @ptr: pointer returned by ipc_alloc | |
408 | * @size: size of block | |
409 | * | |
72fd4a35 | 410 | * Free a block created with ipc_alloc(). The caller must know the size |
1da177e4 LT |
411 | * used in the allocation call. |
412 | */ | |
413 | ||
414 | void ipc_free(void* ptr, int size) | |
415 | { | |
416 | if(size > PAGE_SIZE) | |
417 | vfree(ptr); | |
418 | else | |
419 | kfree(ptr); | |
420 | } | |
421 | ||
422 | /* | |
423 | * rcu allocations: | |
424 | * There are three headers that are prepended to the actual allocation: | |
425 | * - during use: ipc_rcu_hdr. | |
426 | * - during the rcu grace period: ipc_rcu_grace. | |
427 | * - [only if vmalloc]: ipc_rcu_sched. | |
428 | * Their lifetime doesn't overlap, thus the headers share the same memory. | |
429 | * Unlike a normal union, they are right-aligned, thus some container_of | |
430 | * forward/backward casting is necessary: | |
431 | */ | |
432 | struct ipc_rcu_hdr | |
433 | { | |
434 | int refcount; | |
435 | int is_vmalloc; | |
436 | void *data[0]; | |
437 | }; | |
438 | ||
439 | ||
440 | struct ipc_rcu_grace | |
441 | { | |
442 | struct rcu_head rcu; | |
443 | /* "void *" makes sure alignment of following data is sane. */ | |
444 | void *data[0]; | |
445 | }; | |
446 | ||
447 | struct ipc_rcu_sched | |
448 | { | |
449 | struct work_struct work; | |
450 | /* "void *" makes sure alignment of following data is sane. */ | |
451 | void *data[0]; | |
452 | }; | |
453 | ||
454 | #define HDRLEN_KMALLOC (sizeof(struct ipc_rcu_grace) > sizeof(struct ipc_rcu_hdr) ? \ | |
455 | sizeof(struct ipc_rcu_grace) : sizeof(struct ipc_rcu_hdr)) | |
456 | #define HDRLEN_VMALLOC (sizeof(struct ipc_rcu_sched) > HDRLEN_KMALLOC ? \ | |
457 | sizeof(struct ipc_rcu_sched) : HDRLEN_KMALLOC) | |
458 | ||
459 | static inline int rcu_use_vmalloc(int size) | |
460 | { | |
461 | /* Too big for a single page? */ | |
462 | if (HDRLEN_KMALLOC + size > PAGE_SIZE) | |
463 | return 1; | |
464 | return 0; | |
465 | } | |
466 | ||
467 | /** | |
468 | * ipc_rcu_alloc - allocate ipc and rcu space | |
469 | * @size: size desired | |
470 | * | |
471 | * Allocate memory for the rcu header structure + the object. | |
472 | * Returns the pointer to the object. | |
473 | * NULL is returned if the allocation fails. | |
474 | */ | |
475 | ||
476 | void* ipc_rcu_alloc(int size) | |
477 | { | |
478 | void* out; | |
479 | /* | |
480 | * We prepend the allocation with the rcu struct, and | |
481 | * workqueue if necessary (for vmalloc). | |
482 | */ | |
483 | if (rcu_use_vmalloc(size)) { | |
484 | out = vmalloc(HDRLEN_VMALLOC + size); | |
485 | if (out) { | |
486 | out += HDRLEN_VMALLOC; | |
487 | container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 1; | |
488 | container_of(out, struct ipc_rcu_hdr, data)->refcount = 1; | |
489 | } | |
490 | } else { | |
491 | out = kmalloc(HDRLEN_KMALLOC + size, GFP_KERNEL); | |
492 | if (out) { | |
493 | out += HDRLEN_KMALLOC; | |
494 | container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 0; | |
495 | container_of(out, struct ipc_rcu_hdr, data)->refcount = 1; | |
496 | } | |
497 | } | |
498 | ||
499 | return out; | |
500 | } | |
501 | ||
502 | void ipc_rcu_getref(void *ptr) | |
503 | { | |
504 | container_of(ptr, struct ipc_rcu_hdr, data)->refcount++; | |
505 | } | |
506 | ||
65f27f38 DH |
507 | static void ipc_do_vfree(struct work_struct *work) |
508 | { | |
509 | vfree(container_of(work, struct ipc_rcu_sched, work)); | |
510 | } | |
511 | ||
1da177e4 | 512 | /** |
1e5d5331 RD |
513 | * ipc_schedule_free - free ipc + rcu space |
514 | * @head: RCU callback structure for queued work | |
1da177e4 LT |
515 | * |
516 | * Since RCU callback function is called in bh, | |
72fd4a35 | 517 | * we need to defer the vfree to schedule_work(). |
1da177e4 LT |
518 | */ |
519 | static void ipc_schedule_free(struct rcu_head *head) | |
520 | { | |
f4566f04 ND |
521 | struct ipc_rcu_grace *grace; |
522 | struct ipc_rcu_sched *sched; | |
523 | ||
524 | grace = container_of(head, struct ipc_rcu_grace, rcu); | |
525 | sched = container_of(&(grace->data[0]), struct ipc_rcu_sched, | |
526 | data[0]); | |
1da177e4 | 527 | |
65f27f38 | 528 | INIT_WORK(&sched->work, ipc_do_vfree); |
1da177e4 LT |
529 | schedule_work(&sched->work); |
530 | } | |
531 | ||
532 | /** | |
1e5d5331 RD |
533 | * ipc_immediate_free - free ipc + rcu space |
534 | * @head: RCU callback structure that contains pointer to be freed | |
1da177e4 | 535 | * |
72fd4a35 | 536 | * Free from the RCU callback context. |
1da177e4 LT |
537 | */ |
538 | static void ipc_immediate_free(struct rcu_head *head) | |
539 | { | |
540 | struct ipc_rcu_grace *free = | |
541 | container_of(head, struct ipc_rcu_grace, rcu); | |
542 | kfree(free); | |
543 | } | |
544 | ||
545 | void ipc_rcu_putref(void *ptr) | |
546 | { | |
547 | if (--container_of(ptr, struct ipc_rcu_hdr, data)->refcount > 0) | |
548 | return; | |
549 | ||
550 | if (container_of(ptr, struct ipc_rcu_hdr, data)->is_vmalloc) { | |
551 | call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu, | |
552 | ipc_schedule_free); | |
553 | } else { | |
554 | call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu, | |
555 | ipc_immediate_free); | |
556 | } | |
557 | } | |
558 | ||
559 | /** | |
560 | * ipcperms - check IPC permissions | |
561 | * @ipcp: IPC permission set | |
562 | * @flag: desired permission set. | |
563 | * | |
564 | * Check user, group, other permissions for access | |
565 | * to ipc resources. return 0 if allowed | |
566 | */ | |
567 | ||
568 | int ipcperms (struct kern_ipc_perm *ipcp, short flag) | |
569 | { /* flag will most probably be 0 or S_...UGO from <linux/stat.h> */ | |
073115d6 | 570 | int requested_mode, granted_mode, err; |
1da177e4 | 571 | |
073115d6 SG |
572 | if (unlikely((err = audit_ipc_obj(ipcp)))) |
573 | return err; | |
1da177e4 LT |
574 | requested_mode = (flag >> 6) | (flag >> 3) | flag; |
575 | granted_mode = ipcp->mode; | |
576 | if (current->euid == ipcp->cuid || current->euid == ipcp->uid) | |
577 | granted_mode >>= 6; | |
578 | else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid)) | |
579 | granted_mode >>= 3; | |
580 | /* is there some bit set in requested_mode but not in granted_mode? */ | |
581 | if ((requested_mode & ~granted_mode & 0007) && | |
582 | !capable(CAP_IPC_OWNER)) | |
583 | return -1; | |
584 | ||
585 | return security_ipc_permission(ipcp, flag); | |
586 | } | |
587 | ||
588 | /* | |
589 | * Functions to convert between the kern_ipc_perm structure and the | |
590 | * old/new ipc_perm structures | |
591 | */ | |
592 | ||
593 | /** | |
594 | * kernel_to_ipc64_perm - convert kernel ipc permissions to user | |
595 | * @in: kernel permissions | |
596 | * @out: new style IPC permissions | |
597 | * | |
72fd4a35 RD |
598 | * Turn the kernel object @in into a set of permissions descriptions |
599 | * for returning to userspace (@out). | |
1da177e4 LT |
600 | */ |
601 | ||
602 | ||
603 | void kernel_to_ipc64_perm (struct kern_ipc_perm *in, struct ipc64_perm *out) | |
604 | { | |
605 | out->key = in->key; | |
606 | out->uid = in->uid; | |
607 | out->gid = in->gid; | |
608 | out->cuid = in->cuid; | |
609 | out->cgid = in->cgid; | |
610 | out->mode = in->mode; | |
611 | out->seq = in->seq; | |
612 | } | |
613 | ||
614 | /** | |
f4566f04 | 615 | * ipc64_perm_to_ipc_perm - convert new ipc permissions to old |
1da177e4 LT |
616 | * @in: new style IPC permissions |
617 | * @out: old style IPC permissions | |
618 | * | |
72fd4a35 RD |
619 | * Turn the new style permissions object @in into a compatibility |
620 | * object and store it into the @out pointer. | |
1da177e4 LT |
621 | */ |
622 | ||
623 | void ipc64_perm_to_ipc_perm (struct ipc64_perm *in, struct ipc_perm *out) | |
624 | { | |
625 | out->key = in->key; | |
626 | SET_UID(out->uid, in->uid); | |
627 | SET_GID(out->gid, in->gid); | |
628 | SET_UID(out->cuid, in->cuid); | |
629 | SET_GID(out->cgid, in->cgid); | |
630 | out->mode = in->mode; | |
631 | out->seq = in->seq; | |
632 | } | |
633 | ||
f4566f04 | 634 | /** |
3e148c79 | 635 | * ipc_lock - Lock an ipc structure without rw_mutex held |
f4566f04 ND |
636 | * @ids: IPC identifier set |
637 | * @id: ipc id to look for | |
638 | * | |
639 | * Look for an id in the ipc ids idr and lock the associated ipc object. | |
640 | * | |
f4566f04 | 641 | * The ipc object is locked on exit. |
3e148c79 ND |
642 | * |
643 | * This is the routine that should be called when the rw_mutex is not already | |
644 | * held, i.e. idr tree not protected: it protects the idr tree in read mode | |
645 | * during the idr_find(). | |
f4566f04 ND |
646 | */ |
647 | ||
7ca7e564 | 648 | struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id) |
1da177e4 | 649 | { |
7ca7e564 | 650 | struct kern_ipc_perm *out; |
ce621f5b | 651 | int lid = ipcid_to_idx(id); |
1da177e4 | 652 | |
3e148c79 ND |
653 | down_read(&ids->rw_mutex); |
654 | ||
1da177e4 | 655 | rcu_read_lock(); |
7ca7e564 ND |
656 | out = idr_find(&ids->ipcs_idr, lid); |
657 | if (out == NULL) { | |
1da177e4 | 658 | rcu_read_unlock(); |
3e148c79 | 659 | up_read(&ids->rw_mutex); |
023a5355 | 660 | return ERR_PTR(-EINVAL); |
1da177e4 | 661 | } |
7ca7e564 | 662 | |
3e148c79 ND |
663 | up_read(&ids->rw_mutex); |
664 | ||
1da177e4 LT |
665 | spin_lock(&out->lock); |
666 | ||
667 | /* ipc_rmid() may have already freed the ID while ipc_lock | |
668 | * was spinning: here verify that the structure is still valid | |
669 | */ | |
670 | if (out->deleted) { | |
671 | spin_unlock(&out->lock); | |
672 | rcu_read_unlock(); | |
023a5355 | 673 | return ERR_PTR(-EINVAL); |
1da177e4 | 674 | } |
7ca7e564 | 675 | |
1da177e4 LT |
676 | return out; |
677 | } | |
678 | ||
3e148c79 ND |
679 | /** |
680 | * ipc_lock_down - Lock an ipc structure with rw_sem held | |
681 | * @ids: IPC identifier set | |
682 | * @id: ipc id to look for | |
683 | * | |
684 | * Look for an id in the ipc ids idr and lock the associated ipc object. | |
685 | * | |
686 | * The ipc object is locked on exit. | |
687 | * | |
688 | * This is the routine that should be called when the rw_mutex is already | |
689 | * held, i.e. idr tree protected. | |
690 | */ | |
691 | ||
692 | struct kern_ipc_perm *ipc_lock_down(struct ipc_ids *ids, int id) | |
693 | { | |
694 | struct kern_ipc_perm *out; | |
695 | int lid = ipcid_to_idx(id); | |
696 | ||
697 | rcu_read_lock(); | |
698 | out = idr_find(&ids->ipcs_idr, lid); | |
699 | if (out == NULL) { | |
700 | rcu_read_unlock(); | |
701 | return ERR_PTR(-EINVAL); | |
702 | } | |
703 | ||
704 | spin_lock(&out->lock); | |
705 | ||
706 | /* | |
707 | * No need to verify that the structure is still valid since the | |
708 | * rw_mutex is held. | |
709 | */ | |
710 | return out; | |
711 | } | |
712 | ||
b2d75cdd PE |
713 | struct kern_ipc_perm *ipc_lock_check_down(struct ipc_ids *ids, int id) |
714 | { | |
715 | struct kern_ipc_perm *out; | |
716 | ||
717 | out = ipc_lock_down(ids, id); | |
718 | if (IS_ERR(out)) | |
719 | return out; | |
720 | ||
721 | if (ipc_checkid(out, id)) { | |
722 | ipc_unlock(out); | |
723 | return ERR_PTR(-EIDRM); | |
724 | } | |
725 | ||
726 | return out; | |
727 | } | |
728 | ||
729 | struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, int id) | |
730 | { | |
731 | struct kern_ipc_perm *out; | |
732 | ||
733 | out = ipc_lock(ids, id); | |
734 | if (IS_ERR(out)) | |
735 | return out; | |
736 | ||
737 | if (ipc_checkid(out, id)) { | |
738 | ipc_unlock(out); | |
739 | return ERR_PTR(-EIDRM); | |
740 | } | |
741 | ||
742 | return out; | |
743 | } | |
744 | ||
745 | /** | |
746 | * ipcget - Common sys_*get() code | |
747 | * @ns : namsepace | |
748 | * @ids : IPC identifier set | |
749 | * @ops : operations to be called on ipc object creation, permission checks | |
750 | * and further checks | |
751 | * @params : the parameters needed by the previous operations. | |
752 | * | |
753 | * Common routine called by sys_msgget(), sys_semget() and sys_shmget(). | |
754 | */ | |
755 | int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, | |
756 | struct ipc_ops *ops, struct ipc_params *params) | |
757 | { | |
758 | if (params->key == IPC_PRIVATE) | |
759 | return ipcget_new(ns, ids, ops, params); | |
760 | else | |
761 | return ipcget_public(ns, ids, ops, params); | |
762 | } | |
763 | ||
1da177e4 LT |
764 | #ifdef __ARCH_WANT_IPC_PARSE_VERSION |
765 | ||
766 | ||
767 | /** | |
768 | * ipc_parse_version - IPC call version | |
769 | * @cmd: pointer to command | |
770 | * | |
771 | * Return IPC_64 for new style IPC and IPC_OLD for old style IPC. | |
72fd4a35 | 772 | * The @cmd value is turned from an encoding command and version into |
1da177e4 LT |
773 | * just the command code. |
774 | */ | |
775 | ||
776 | int ipc_parse_version (int *cmd) | |
777 | { | |
778 | if (*cmd & IPC_64) { | |
779 | *cmd ^= IPC_64; | |
780 | return IPC_64; | |
781 | } else { | |
782 | return IPC_OLD; | |
783 | } | |
784 | } | |
785 | ||
786 | #endif /* __ARCH_WANT_IPC_PARSE_VERSION */ | |
ae781774 MW |
787 | |
788 | #ifdef CONFIG_PROC_FS | |
bc1fc6d8 EB |
789 | struct ipc_proc_iter { |
790 | struct ipc_namespace *ns; | |
791 | struct ipc_proc_iface *iface; | |
792 | }; | |
793 | ||
7ca7e564 ND |
794 | /* |
795 | * This routine locks the ipc structure found at least at position pos. | |
796 | */ | |
b524b9ad AB |
797 | static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos, |
798 | loff_t *new_pos) | |
ae781774 | 799 | { |
7ca7e564 ND |
800 | struct kern_ipc_perm *ipc; |
801 | int total, id; | |
73ea4130 | 802 | |
7ca7e564 ND |
803 | total = 0; |
804 | for (id = 0; id < pos && total < ids->in_use; id++) { | |
805 | ipc = idr_find(&ids->ipcs_idr, id); | |
806 | if (ipc != NULL) | |
807 | total++; | |
808 | } | |
ae781774 | 809 | |
7ca7e564 ND |
810 | if (total >= ids->in_use) |
811 | return NULL; | |
ae781774 | 812 | |
7ca7e564 ND |
813 | for ( ; pos < IPCMNI; pos++) { |
814 | ipc = idr_find(&ids->ipcs_idr, pos); | |
815 | if (ipc != NULL) { | |
816 | *new_pos = pos + 1; | |
817 | ipc_lock_by_ptr(ipc); | |
ae781774 MW |
818 | return ipc; |
819 | } | |
820 | } | |
821 | ||
822 | /* Out of range - return NULL to terminate iteration */ | |
823 | return NULL; | |
824 | } | |
825 | ||
7ca7e564 ND |
826 | static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos) |
827 | { | |
828 | struct ipc_proc_iter *iter = s->private; | |
829 | struct ipc_proc_iface *iface = iter->iface; | |
830 | struct kern_ipc_perm *ipc = it; | |
831 | ||
832 | /* If we had an ipc id locked before, unlock it */ | |
833 | if (ipc && ipc != SEQ_START_TOKEN) | |
834 | ipc_unlock(ipc); | |
835 | ||
ed2ddbf8 | 836 | return sysvipc_find_ipc(&iter->ns->ids[iface->ids], *pos, pos); |
7ca7e564 ND |
837 | } |
838 | ||
ae781774 | 839 | /* |
f4566f04 ND |
840 | * File positions: pos 0 -> header, pos n -> ipc id = n - 1. |
841 | * SeqFile iterator: iterator value locked ipc pointer or SEQ_TOKEN_START. | |
ae781774 MW |
842 | */ |
843 | static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos) | |
844 | { | |
bc1fc6d8 EB |
845 | struct ipc_proc_iter *iter = s->private; |
846 | struct ipc_proc_iface *iface = iter->iface; | |
73ea4130 KK |
847 | struct ipc_ids *ids; |
848 | ||
ed2ddbf8 | 849 | ids = &iter->ns->ids[iface->ids]; |
ae781774 MW |
850 | |
851 | /* | |
852 | * Take the lock - this will be released by the corresponding | |
853 | * call to stop(). | |
854 | */ | |
3e148c79 | 855 | down_read(&ids->rw_mutex); |
ae781774 MW |
856 | |
857 | /* pos < 0 is invalid */ | |
858 | if (*pos < 0) | |
859 | return NULL; | |
860 | ||
861 | /* pos == 0 means header */ | |
862 | if (*pos == 0) | |
863 | return SEQ_START_TOKEN; | |
864 | ||
865 | /* Find the (pos-1)th ipc */ | |
7ca7e564 | 866 | return sysvipc_find_ipc(ids, *pos - 1, pos); |
ae781774 MW |
867 | } |
868 | ||
869 | static void sysvipc_proc_stop(struct seq_file *s, void *it) | |
870 | { | |
871 | struct kern_ipc_perm *ipc = it; | |
bc1fc6d8 EB |
872 | struct ipc_proc_iter *iter = s->private; |
873 | struct ipc_proc_iface *iface = iter->iface; | |
73ea4130 | 874 | struct ipc_ids *ids; |
ae781774 | 875 | |
f4566f04 | 876 | /* If we had a locked structure, release it */ |
ae781774 MW |
877 | if (ipc && ipc != SEQ_START_TOKEN) |
878 | ipc_unlock(ipc); | |
879 | ||
ed2ddbf8 | 880 | ids = &iter->ns->ids[iface->ids]; |
ae781774 | 881 | /* Release the lock we took in start() */ |
3e148c79 | 882 | up_read(&ids->rw_mutex); |
ae781774 MW |
883 | } |
884 | ||
885 | static int sysvipc_proc_show(struct seq_file *s, void *it) | |
886 | { | |
bc1fc6d8 EB |
887 | struct ipc_proc_iter *iter = s->private; |
888 | struct ipc_proc_iface *iface = iter->iface; | |
ae781774 MW |
889 | |
890 | if (it == SEQ_START_TOKEN) | |
891 | return seq_puts(s, iface->header); | |
892 | ||
893 | return iface->show(s, it); | |
894 | } | |
895 | ||
896 | static struct seq_operations sysvipc_proc_seqops = { | |
897 | .start = sysvipc_proc_start, | |
898 | .stop = sysvipc_proc_stop, | |
899 | .next = sysvipc_proc_next, | |
900 | .show = sysvipc_proc_show, | |
901 | }; | |
902 | ||
bc1fc6d8 EB |
903 | static int sysvipc_proc_open(struct inode *inode, struct file *file) |
904 | { | |
ae781774 MW |
905 | int ret; |
906 | struct seq_file *seq; | |
bc1fc6d8 EB |
907 | struct ipc_proc_iter *iter; |
908 | ||
909 | ret = -ENOMEM; | |
910 | iter = kmalloc(sizeof(*iter), GFP_KERNEL); | |
911 | if (!iter) | |
912 | goto out; | |
ae781774 MW |
913 | |
914 | ret = seq_open(file, &sysvipc_proc_seqops); | |
bc1fc6d8 EB |
915 | if (ret) |
916 | goto out_kfree; | |
917 | ||
918 | seq = file->private_data; | |
919 | seq->private = iter; | |
920 | ||
921 | iter->iface = PDE(inode)->data; | |
922 | iter->ns = get_ipc_ns(current->nsproxy->ipc_ns); | |
923 | out: | |
ae781774 | 924 | return ret; |
bc1fc6d8 EB |
925 | out_kfree: |
926 | kfree(iter); | |
927 | goto out; | |
928 | } | |
929 | ||
930 | static int sysvipc_proc_release(struct inode *inode, struct file *file) | |
931 | { | |
932 | struct seq_file *seq = file->private_data; | |
933 | struct ipc_proc_iter *iter = seq->private; | |
934 | put_ipc_ns(iter->ns); | |
935 | return seq_release_private(inode, file); | |
ae781774 MW |
936 | } |
937 | ||
9a32144e | 938 | static const struct file_operations sysvipc_proc_fops = { |
ae781774 MW |
939 | .open = sysvipc_proc_open, |
940 | .read = seq_read, | |
941 | .llseek = seq_lseek, | |
bc1fc6d8 | 942 | .release = sysvipc_proc_release, |
ae781774 MW |
943 | }; |
944 | #endif /* CONFIG_PROC_FS */ |