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 | ||
48dea404 | 234 | new->id = ipc_buildid(id, new->seq); |
1da177e4 LT |
235 | spin_lock_init(&new->lock); |
236 | new->deleted = 0; | |
237 | rcu_read_lock(); | |
238 | spin_lock(&new->lock); | |
1da177e4 LT |
239 | return id; |
240 | } | |
241 | ||
7748dbfa ND |
242 | /** |
243 | * ipcget_new - create a new ipc object | |
244 | * @ns: namespace | |
f4566f04 | 245 | * @ids: IPC identifer set |
7748dbfa ND |
246 | * @ops: the actual creation routine to call |
247 | * @params: its parameters | |
248 | * | |
f4566f04 ND |
249 | * This routine is called by sys_msgget, sys_semget() and sys_shmget() |
250 | * when the key is IPC_PRIVATE. | |
7748dbfa | 251 | */ |
b2d75cdd | 252 | static int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids, |
7748dbfa ND |
253 | struct ipc_ops *ops, struct ipc_params *params) |
254 | { | |
255 | int err; | |
283bb7fa | 256 | retry: |
7748dbfa ND |
257 | err = idr_pre_get(&ids->ipcs_idr, GFP_KERNEL); |
258 | ||
259 | if (!err) | |
260 | return -ENOMEM; | |
261 | ||
3e148c79 | 262 | down_write(&ids->rw_mutex); |
7748dbfa | 263 | err = ops->getnew(ns, params); |
3e148c79 | 264 | up_write(&ids->rw_mutex); |
7748dbfa | 265 | |
283bb7fa PP |
266 | if (err == -EAGAIN) |
267 | goto retry; | |
268 | ||
7748dbfa ND |
269 | return err; |
270 | } | |
271 | ||
272 | /** | |
273 | * ipc_check_perms - check security and permissions for an IPC | |
274 | * @ipcp: ipc permission set | |
7748dbfa ND |
275 | * @ops: the actual security routine to call |
276 | * @params: its parameters | |
f4566f04 ND |
277 | * |
278 | * This routine is called by sys_msgget(), sys_semget() and sys_shmget() | |
279 | * when the key is not IPC_PRIVATE and that key already exists in the | |
280 | * ids IDR. | |
281 | * | |
282 | * On success, the IPC id is returned. | |
283 | * | |
3e148c79 | 284 | * It is called with ipc_ids.rw_mutex and ipcp->lock held. |
7748dbfa ND |
285 | */ |
286 | static int ipc_check_perms(struct kern_ipc_perm *ipcp, struct ipc_ops *ops, | |
287 | struct ipc_params *params) | |
288 | { | |
289 | int err; | |
290 | ||
291 | if (ipcperms(ipcp, params->flg)) | |
292 | err = -EACCES; | |
293 | else { | |
294 | err = ops->associate(ipcp, params->flg); | |
295 | if (!err) | |
296 | err = ipcp->id; | |
297 | } | |
298 | ||
299 | return err; | |
300 | } | |
301 | ||
302 | /** | |
303 | * ipcget_public - get an ipc object or create a new one | |
304 | * @ns: namespace | |
f4566f04 | 305 | * @ids: IPC identifer set |
7748dbfa ND |
306 | * @ops: the actual creation routine to call |
307 | * @params: its parameters | |
308 | * | |
f4566f04 ND |
309 | * This routine is called by sys_msgget, sys_semget() and sys_shmget() |
310 | * when the key is not IPC_PRIVATE. | |
311 | * It adds a new entry if the key is not found and does some permission | |
312 | * / security checkings if the key is found. | |
313 | * | |
314 | * On success, the ipc id is returned. | |
7748dbfa | 315 | */ |
b2d75cdd | 316 | static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids, |
7748dbfa ND |
317 | struct ipc_ops *ops, struct ipc_params *params) |
318 | { | |
319 | struct kern_ipc_perm *ipcp; | |
320 | int flg = params->flg; | |
321 | int err; | |
283bb7fa | 322 | retry: |
7748dbfa ND |
323 | err = idr_pre_get(&ids->ipcs_idr, GFP_KERNEL); |
324 | ||
3e148c79 ND |
325 | /* |
326 | * Take the lock as a writer since we are potentially going to add | |
327 | * a new entry + read locks are not "upgradable" | |
328 | */ | |
329 | down_write(&ids->rw_mutex); | |
7748dbfa ND |
330 | ipcp = ipc_findkey(ids, params->key); |
331 | if (ipcp == NULL) { | |
332 | /* key not used */ | |
333 | if (!(flg & IPC_CREAT)) | |
334 | err = -ENOENT; | |
335 | else if (!err) | |
336 | err = -ENOMEM; | |
337 | else | |
338 | err = ops->getnew(ns, params); | |
339 | } else { | |
340 | /* ipc object has been locked by ipc_findkey() */ | |
341 | ||
342 | if (flg & IPC_CREAT && flg & IPC_EXCL) | |
343 | err = -EEXIST; | |
344 | else { | |
345 | err = 0; | |
346 | if (ops->more_checks) | |
347 | err = ops->more_checks(ipcp, params); | |
348 | if (!err) | |
f4566f04 ND |
349 | /* |
350 | * ipc_check_perms returns the IPC id on | |
351 | * success | |
352 | */ | |
7748dbfa ND |
353 | err = ipc_check_perms(ipcp, ops, params); |
354 | } | |
355 | ipc_unlock(ipcp); | |
356 | } | |
3e148c79 | 357 | up_write(&ids->rw_mutex); |
7748dbfa | 358 | |
283bb7fa PP |
359 | if (err == -EAGAIN) |
360 | goto retry; | |
361 | ||
7748dbfa ND |
362 | return err; |
363 | } | |
364 | ||
365 | ||
1da177e4 LT |
366 | /** |
367 | * ipc_rmid - remove an IPC identifier | |
f4566f04 ND |
368 | * @ids: IPC identifier set |
369 | * @ipcp: ipc perm structure containing the identifier to remove | |
1da177e4 | 370 | * |
3e148c79 ND |
371 | * ipc_ids.rw_mutex (as a writer) and the spinlock for this ID are held |
372 | * before this function is called, and remain locked on the exit. | |
1da177e4 LT |
373 | */ |
374 | ||
7ca7e564 | 375 | void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp) |
1da177e4 | 376 | { |
ce621f5b | 377 | int lid = ipcid_to_idx(ipcp->id); |
7ca7e564 ND |
378 | |
379 | idr_remove(&ids->ipcs_idr, lid); | |
1da177e4 | 380 | |
1da177e4 LT |
381 | ids->in_use--; |
382 | ||
7ca7e564 ND |
383 | ipcp->deleted = 1; |
384 | ||
385 | return; | |
1da177e4 LT |
386 | } |
387 | ||
388 | /** | |
389 | * ipc_alloc - allocate ipc space | |
390 | * @size: size desired | |
391 | * | |
392 | * Allocate memory from the appropriate pools and return a pointer to it. | |
393 | * NULL is returned if the allocation fails | |
394 | */ | |
395 | ||
396 | void* ipc_alloc(int size) | |
397 | { | |
398 | void* out; | |
399 | if(size > PAGE_SIZE) | |
400 | out = vmalloc(size); | |
401 | else | |
402 | out = kmalloc(size, GFP_KERNEL); | |
403 | return out; | |
404 | } | |
405 | ||
406 | /** | |
407 | * ipc_free - free ipc space | |
408 | * @ptr: pointer returned by ipc_alloc | |
409 | * @size: size of block | |
410 | * | |
72fd4a35 | 411 | * Free a block created with ipc_alloc(). The caller must know the size |
1da177e4 LT |
412 | * used in the allocation call. |
413 | */ | |
414 | ||
415 | void ipc_free(void* ptr, int size) | |
416 | { | |
417 | if(size > PAGE_SIZE) | |
418 | vfree(ptr); | |
419 | else | |
420 | kfree(ptr); | |
421 | } | |
422 | ||
423 | /* | |
424 | * rcu allocations: | |
425 | * There are three headers that are prepended to the actual allocation: | |
426 | * - during use: ipc_rcu_hdr. | |
427 | * - during the rcu grace period: ipc_rcu_grace. | |
428 | * - [only if vmalloc]: ipc_rcu_sched. | |
429 | * Their lifetime doesn't overlap, thus the headers share the same memory. | |
430 | * Unlike a normal union, they are right-aligned, thus some container_of | |
431 | * forward/backward casting is necessary: | |
432 | */ | |
433 | struct ipc_rcu_hdr | |
434 | { | |
435 | int refcount; | |
436 | int is_vmalloc; | |
437 | void *data[0]; | |
438 | }; | |
439 | ||
440 | ||
441 | struct ipc_rcu_grace | |
442 | { | |
443 | struct rcu_head rcu; | |
444 | /* "void *" makes sure alignment of following data is sane. */ | |
445 | void *data[0]; | |
446 | }; | |
447 | ||
448 | struct ipc_rcu_sched | |
449 | { | |
450 | struct work_struct work; | |
451 | /* "void *" makes sure alignment of following data is sane. */ | |
452 | void *data[0]; | |
453 | }; | |
454 | ||
455 | #define HDRLEN_KMALLOC (sizeof(struct ipc_rcu_grace) > sizeof(struct ipc_rcu_hdr) ? \ | |
456 | sizeof(struct ipc_rcu_grace) : sizeof(struct ipc_rcu_hdr)) | |
457 | #define HDRLEN_VMALLOC (sizeof(struct ipc_rcu_sched) > HDRLEN_KMALLOC ? \ | |
458 | sizeof(struct ipc_rcu_sched) : HDRLEN_KMALLOC) | |
459 | ||
460 | static inline int rcu_use_vmalloc(int size) | |
461 | { | |
462 | /* Too big for a single page? */ | |
463 | if (HDRLEN_KMALLOC + size > PAGE_SIZE) | |
464 | return 1; | |
465 | return 0; | |
466 | } | |
467 | ||
468 | /** | |
469 | * ipc_rcu_alloc - allocate ipc and rcu space | |
470 | * @size: size desired | |
471 | * | |
472 | * Allocate memory for the rcu header structure + the object. | |
473 | * Returns the pointer to the object. | |
474 | * NULL is returned if the allocation fails. | |
475 | */ | |
476 | ||
477 | void* ipc_rcu_alloc(int size) | |
478 | { | |
479 | void* out; | |
480 | /* | |
481 | * We prepend the allocation with the rcu struct, and | |
482 | * workqueue if necessary (for vmalloc). | |
483 | */ | |
484 | if (rcu_use_vmalloc(size)) { | |
485 | out = vmalloc(HDRLEN_VMALLOC + size); | |
486 | if (out) { | |
487 | out += HDRLEN_VMALLOC; | |
488 | container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 1; | |
489 | container_of(out, struct ipc_rcu_hdr, data)->refcount = 1; | |
490 | } | |
491 | } else { | |
492 | out = kmalloc(HDRLEN_KMALLOC + size, GFP_KERNEL); | |
493 | if (out) { | |
494 | out += HDRLEN_KMALLOC; | |
495 | container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 0; | |
496 | container_of(out, struct ipc_rcu_hdr, data)->refcount = 1; | |
497 | } | |
498 | } | |
499 | ||
500 | return out; | |
501 | } | |
502 | ||
503 | void ipc_rcu_getref(void *ptr) | |
504 | { | |
505 | container_of(ptr, struct ipc_rcu_hdr, data)->refcount++; | |
506 | } | |
507 | ||
65f27f38 DH |
508 | static void ipc_do_vfree(struct work_struct *work) |
509 | { | |
510 | vfree(container_of(work, struct ipc_rcu_sched, work)); | |
511 | } | |
512 | ||
1da177e4 | 513 | /** |
1e5d5331 RD |
514 | * ipc_schedule_free - free ipc + rcu space |
515 | * @head: RCU callback structure for queued work | |
1da177e4 LT |
516 | * |
517 | * Since RCU callback function is called in bh, | |
72fd4a35 | 518 | * we need to defer the vfree to schedule_work(). |
1da177e4 LT |
519 | */ |
520 | static void ipc_schedule_free(struct rcu_head *head) | |
521 | { | |
f4566f04 ND |
522 | struct ipc_rcu_grace *grace; |
523 | struct ipc_rcu_sched *sched; | |
524 | ||
525 | grace = container_of(head, struct ipc_rcu_grace, rcu); | |
526 | sched = container_of(&(grace->data[0]), struct ipc_rcu_sched, | |
527 | data[0]); | |
1da177e4 | 528 | |
65f27f38 | 529 | INIT_WORK(&sched->work, ipc_do_vfree); |
1da177e4 LT |
530 | schedule_work(&sched->work); |
531 | } | |
532 | ||
533 | /** | |
1e5d5331 RD |
534 | * ipc_immediate_free - free ipc + rcu space |
535 | * @head: RCU callback structure that contains pointer to be freed | |
1da177e4 | 536 | * |
72fd4a35 | 537 | * Free from the RCU callback context. |
1da177e4 LT |
538 | */ |
539 | static void ipc_immediate_free(struct rcu_head *head) | |
540 | { | |
541 | struct ipc_rcu_grace *free = | |
542 | container_of(head, struct ipc_rcu_grace, rcu); | |
543 | kfree(free); | |
544 | } | |
545 | ||
546 | void ipc_rcu_putref(void *ptr) | |
547 | { | |
548 | if (--container_of(ptr, struct ipc_rcu_hdr, data)->refcount > 0) | |
549 | return; | |
550 | ||
551 | if (container_of(ptr, struct ipc_rcu_hdr, data)->is_vmalloc) { | |
552 | call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu, | |
553 | ipc_schedule_free); | |
554 | } else { | |
555 | call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu, | |
556 | ipc_immediate_free); | |
557 | } | |
558 | } | |
559 | ||
560 | /** | |
561 | * ipcperms - check IPC permissions | |
562 | * @ipcp: IPC permission set | |
563 | * @flag: desired permission set. | |
564 | * | |
565 | * Check user, group, other permissions for access | |
566 | * to ipc resources. return 0 if allowed | |
567 | */ | |
568 | ||
569 | int ipcperms (struct kern_ipc_perm *ipcp, short flag) | |
570 | { /* flag will most probably be 0 or S_...UGO from <linux/stat.h> */ | |
073115d6 | 571 | int requested_mode, granted_mode, err; |
1da177e4 | 572 | |
073115d6 SG |
573 | if (unlikely((err = audit_ipc_obj(ipcp)))) |
574 | return err; | |
1da177e4 LT |
575 | requested_mode = (flag >> 6) | (flag >> 3) | flag; |
576 | granted_mode = ipcp->mode; | |
577 | if (current->euid == ipcp->cuid || current->euid == ipcp->uid) | |
578 | granted_mode >>= 6; | |
579 | else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid)) | |
580 | granted_mode >>= 3; | |
581 | /* is there some bit set in requested_mode but not in granted_mode? */ | |
582 | if ((requested_mode & ~granted_mode & 0007) && | |
583 | !capable(CAP_IPC_OWNER)) | |
584 | return -1; | |
585 | ||
586 | return security_ipc_permission(ipcp, flag); | |
587 | } | |
588 | ||
589 | /* | |
590 | * Functions to convert between the kern_ipc_perm structure and the | |
591 | * old/new ipc_perm structures | |
592 | */ | |
593 | ||
594 | /** | |
595 | * kernel_to_ipc64_perm - convert kernel ipc permissions to user | |
596 | * @in: kernel permissions | |
597 | * @out: new style IPC permissions | |
598 | * | |
72fd4a35 RD |
599 | * Turn the kernel object @in into a set of permissions descriptions |
600 | * for returning to userspace (@out). | |
1da177e4 LT |
601 | */ |
602 | ||
603 | ||
604 | void kernel_to_ipc64_perm (struct kern_ipc_perm *in, struct ipc64_perm *out) | |
605 | { | |
606 | out->key = in->key; | |
607 | out->uid = in->uid; | |
608 | out->gid = in->gid; | |
609 | out->cuid = in->cuid; | |
610 | out->cgid = in->cgid; | |
611 | out->mode = in->mode; | |
612 | out->seq = in->seq; | |
613 | } | |
614 | ||
615 | /** | |
f4566f04 | 616 | * ipc64_perm_to_ipc_perm - convert new ipc permissions to old |
1da177e4 LT |
617 | * @in: new style IPC permissions |
618 | * @out: old style IPC permissions | |
619 | * | |
72fd4a35 RD |
620 | * Turn the new style permissions object @in into a compatibility |
621 | * object and store it into the @out pointer. | |
1da177e4 LT |
622 | */ |
623 | ||
624 | void ipc64_perm_to_ipc_perm (struct ipc64_perm *in, struct ipc_perm *out) | |
625 | { | |
626 | out->key = in->key; | |
627 | SET_UID(out->uid, in->uid); | |
628 | SET_GID(out->gid, in->gid); | |
629 | SET_UID(out->cuid, in->cuid); | |
630 | SET_GID(out->cgid, in->cgid); | |
631 | out->mode = in->mode; | |
632 | out->seq = in->seq; | |
633 | } | |
634 | ||
f4566f04 | 635 | /** |
3e148c79 | 636 | * ipc_lock - Lock an ipc structure without rw_mutex held |
f4566f04 ND |
637 | * @ids: IPC identifier set |
638 | * @id: ipc id to look for | |
639 | * | |
640 | * Look for an id in the ipc ids idr and lock the associated ipc object. | |
641 | * | |
f4566f04 | 642 | * The ipc object is locked on exit. |
3e148c79 ND |
643 | * |
644 | * This is the routine that should be called when the rw_mutex is not already | |
645 | * held, i.e. idr tree not protected: it protects the idr tree in read mode | |
646 | * during the idr_find(). | |
f4566f04 ND |
647 | */ |
648 | ||
7ca7e564 | 649 | struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id) |
1da177e4 | 650 | { |
7ca7e564 | 651 | struct kern_ipc_perm *out; |
ce621f5b | 652 | int lid = ipcid_to_idx(id); |
1da177e4 | 653 | |
3e148c79 ND |
654 | down_read(&ids->rw_mutex); |
655 | ||
1da177e4 | 656 | rcu_read_lock(); |
7ca7e564 ND |
657 | out = idr_find(&ids->ipcs_idr, lid); |
658 | if (out == NULL) { | |
1da177e4 | 659 | rcu_read_unlock(); |
3e148c79 | 660 | up_read(&ids->rw_mutex); |
023a5355 | 661 | return ERR_PTR(-EINVAL); |
1da177e4 | 662 | } |
7ca7e564 | 663 | |
3e148c79 ND |
664 | up_read(&ids->rw_mutex); |
665 | ||
1da177e4 LT |
666 | spin_lock(&out->lock); |
667 | ||
668 | /* ipc_rmid() may have already freed the ID while ipc_lock | |
669 | * was spinning: here verify that the structure is still valid | |
670 | */ | |
671 | if (out->deleted) { | |
672 | spin_unlock(&out->lock); | |
673 | rcu_read_unlock(); | |
023a5355 | 674 | return ERR_PTR(-EINVAL); |
1da177e4 | 675 | } |
7ca7e564 | 676 | |
1da177e4 LT |
677 | return out; |
678 | } | |
679 | ||
3e148c79 ND |
680 | /** |
681 | * ipc_lock_down - Lock an ipc structure with rw_sem held | |
682 | * @ids: IPC identifier set | |
683 | * @id: ipc id to look for | |
684 | * | |
685 | * Look for an id in the ipc ids idr and lock the associated ipc object. | |
686 | * | |
687 | * The ipc object is locked on exit. | |
688 | * | |
689 | * This is the routine that should be called when the rw_mutex is already | |
690 | * held, i.e. idr tree protected. | |
691 | */ | |
692 | ||
693 | struct kern_ipc_perm *ipc_lock_down(struct ipc_ids *ids, int id) | |
694 | { | |
695 | struct kern_ipc_perm *out; | |
696 | int lid = ipcid_to_idx(id); | |
697 | ||
698 | rcu_read_lock(); | |
699 | out = idr_find(&ids->ipcs_idr, lid); | |
700 | if (out == NULL) { | |
701 | rcu_read_unlock(); | |
702 | return ERR_PTR(-EINVAL); | |
703 | } | |
704 | ||
705 | spin_lock(&out->lock); | |
706 | ||
707 | /* | |
708 | * No need to verify that the structure is still valid since the | |
709 | * rw_mutex is held. | |
710 | */ | |
711 | return out; | |
712 | } | |
713 | ||
b2d75cdd PE |
714 | struct kern_ipc_perm *ipc_lock_check_down(struct ipc_ids *ids, int id) |
715 | { | |
716 | struct kern_ipc_perm *out; | |
717 | ||
718 | out = ipc_lock_down(ids, id); | |
719 | if (IS_ERR(out)) | |
720 | return out; | |
721 | ||
722 | if (ipc_checkid(out, id)) { | |
723 | ipc_unlock(out); | |
724 | return ERR_PTR(-EIDRM); | |
725 | } | |
726 | ||
727 | return out; | |
728 | } | |
729 | ||
730 | struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, int id) | |
731 | { | |
732 | struct kern_ipc_perm *out; | |
733 | ||
734 | out = ipc_lock(ids, id); | |
735 | if (IS_ERR(out)) | |
736 | return out; | |
737 | ||
738 | if (ipc_checkid(out, id)) { | |
739 | ipc_unlock(out); | |
740 | return ERR_PTR(-EIDRM); | |
741 | } | |
742 | ||
743 | return out; | |
744 | } | |
745 | ||
746 | /** | |
747 | * ipcget - Common sys_*get() code | |
748 | * @ns : namsepace | |
749 | * @ids : IPC identifier set | |
750 | * @ops : operations to be called on ipc object creation, permission checks | |
751 | * and further checks | |
752 | * @params : the parameters needed by the previous operations. | |
753 | * | |
754 | * Common routine called by sys_msgget(), sys_semget() and sys_shmget(). | |
755 | */ | |
756 | int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, | |
757 | struct ipc_ops *ops, struct ipc_params *params) | |
758 | { | |
759 | if (params->key == IPC_PRIVATE) | |
760 | return ipcget_new(ns, ids, ops, params); | |
761 | else | |
762 | return ipcget_public(ns, ids, ops, params); | |
763 | } | |
764 | ||
1da177e4 LT |
765 | #ifdef __ARCH_WANT_IPC_PARSE_VERSION |
766 | ||
767 | ||
768 | /** | |
769 | * ipc_parse_version - IPC call version | |
770 | * @cmd: pointer to command | |
771 | * | |
772 | * Return IPC_64 for new style IPC and IPC_OLD for old style IPC. | |
72fd4a35 | 773 | * The @cmd value is turned from an encoding command and version into |
1da177e4 LT |
774 | * just the command code. |
775 | */ | |
776 | ||
777 | int ipc_parse_version (int *cmd) | |
778 | { | |
779 | if (*cmd & IPC_64) { | |
780 | *cmd ^= IPC_64; | |
781 | return IPC_64; | |
782 | } else { | |
783 | return IPC_OLD; | |
784 | } | |
785 | } | |
786 | ||
787 | #endif /* __ARCH_WANT_IPC_PARSE_VERSION */ | |
ae781774 MW |
788 | |
789 | #ifdef CONFIG_PROC_FS | |
bc1fc6d8 EB |
790 | struct ipc_proc_iter { |
791 | struct ipc_namespace *ns; | |
792 | struct ipc_proc_iface *iface; | |
793 | }; | |
794 | ||
7ca7e564 ND |
795 | /* |
796 | * This routine locks the ipc structure found at least at position pos. | |
797 | */ | |
b524b9ad AB |
798 | static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos, |
799 | loff_t *new_pos) | |
ae781774 | 800 | { |
7ca7e564 ND |
801 | struct kern_ipc_perm *ipc; |
802 | int total, id; | |
73ea4130 | 803 | |
7ca7e564 ND |
804 | total = 0; |
805 | for (id = 0; id < pos && total < ids->in_use; id++) { | |
806 | ipc = idr_find(&ids->ipcs_idr, id); | |
807 | if (ipc != NULL) | |
808 | total++; | |
809 | } | |
ae781774 | 810 | |
7ca7e564 ND |
811 | if (total >= ids->in_use) |
812 | return NULL; | |
ae781774 | 813 | |
7ca7e564 ND |
814 | for ( ; pos < IPCMNI; pos++) { |
815 | ipc = idr_find(&ids->ipcs_idr, pos); | |
816 | if (ipc != NULL) { | |
817 | *new_pos = pos + 1; | |
818 | ipc_lock_by_ptr(ipc); | |
ae781774 MW |
819 | return ipc; |
820 | } | |
821 | } | |
822 | ||
823 | /* Out of range - return NULL to terminate iteration */ | |
824 | return NULL; | |
825 | } | |
826 | ||
7ca7e564 ND |
827 | static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos) |
828 | { | |
829 | struct ipc_proc_iter *iter = s->private; | |
830 | struct ipc_proc_iface *iface = iter->iface; | |
831 | struct kern_ipc_perm *ipc = it; | |
832 | ||
833 | /* If we had an ipc id locked before, unlock it */ | |
834 | if (ipc && ipc != SEQ_START_TOKEN) | |
835 | ipc_unlock(ipc); | |
836 | ||
ed2ddbf8 | 837 | return sysvipc_find_ipc(&iter->ns->ids[iface->ids], *pos, pos); |
7ca7e564 ND |
838 | } |
839 | ||
ae781774 | 840 | /* |
f4566f04 ND |
841 | * File positions: pos 0 -> header, pos n -> ipc id = n - 1. |
842 | * SeqFile iterator: iterator value locked ipc pointer or SEQ_TOKEN_START. | |
ae781774 MW |
843 | */ |
844 | static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos) | |
845 | { | |
bc1fc6d8 EB |
846 | struct ipc_proc_iter *iter = s->private; |
847 | struct ipc_proc_iface *iface = iter->iface; | |
73ea4130 KK |
848 | struct ipc_ids *ids; |
849 | ||
ed2ddbf8 | 850 | ids = &iter->ns->ids[iface->ids]; |
ae781774 MW |
851 | |
852 | /* | |
853 | * Take the lock - this will be released by the corresponding | |
854 | * call to stop(). | |
855 | */ | |
3e148c79 | 856 | down_read(&ids->rw_mutex); |
ae781774 MW |
857 | |
858 | /* pos < 0 is invalid */ | |
859 | if (*pos < 0) | |
860 | return NULL; | |
861 | ||
862 | /* pos == 0 means header */ | |
863 | if (*pos == 0) | |
864 | return SEQ_START_TOKEN; | |
865 | ||
866 | /* Find the (pos-1)th ipc */ | |
7ca7e564 | 867 | return sysvipc_find_ipc(ids, *pos - 1, pos); |
ae781774 MW |
868 | } |
869 | ||
870 | static void sysvipc_proc_stop(struct seq_file *s, void *it) | |
871 | { | |
872 | struct kern_ipc_perm *ipc = it; | |
bc1fc6d8 EB |
873 | struct ipc_proc_iter *iter = s->private; |
874 | struct ipc_proc_iface *iface = iter->iface; | |
73ea4130 | 875 | struct ipc_ids *ids; |
ae781774 | 876 | |
f4566f04 | 877 | /* If we had a locked structure, release it */ |
ae781774 MW |
878 | if (ipc && ipc != SEQ_START_TOKEN) |
879 | ipc_unlock(ipc); | |
880 | ||
ed2ddbf8 | 881 | ids = &iter->ns->ids[iface->ids]; |
ae781774 | 882 | /* Release the lock we took in start() */ |
3e148c79 | 883 | up_read(&ids->rw_mutex); |
ae781774 MW |
884 | } |
885 | ||
886 | static int sysvipc_proc_show(struct seq_file *s, void *it) | |
887 | { | |
bc1fc6d8 EB |
888 | struct ipc_proc_iter *iter = s->private; |
889 | struct ipc_proc_iface *iface = iter->iface; | |
ae781774 MW |
890 | |
891 | if (it == SEQ_START_TOKEN) | |
892 | return seq_puts(s, iface->header); | |
893 | ||
894 | return iface->show(s, it); | |
895 | } | |
896 | ||
897 | static struct seq_operations sysvipc_proc_seqops = { | |
898 | .start = sysvipc_proc_start, | |
899 | .stop = sysvipc_proc_stop, | |
900 | .next = sysvipc_proc_next, | |
901 | .show = sysvipc_proc_show, | |
902 | }; | |
903 | ||
bc1fc6d8 EB |
904 | static int sysvipc_proc_open(struct inode *inode, struct file *file) |
905 | { | |
ae781774 MW |
906 | int ret; |
907 | struct seq_file *seq; | |
bc1fc6d8 EB |
908 | struct ipc_proc_iter *iter; |
909 | ||
910 | ret = -ENOMEM; | |
911 | iter = kmalloc(sizeof(*iter), GFP_KERNEL); | |
912 | if (!iter) | |
913 | goto out; | |
ae781774 MW |
914 | |
915 | ret = seq_open(file, &sysvipc_proc_seqops); | |
bc1fc6d8 EB |
916 | if (ret) |
917 | goto out_kfree; | |
918 | ||
919 | seq = file->private_data; | |
920 | seq->private = iter; | |
921 | ||
922 | iter->iface = PDE(inode)->data; | |
923 | iter->ns = get_ipc_ns(current->nsproxy->ipc_ns); | |
924 | out: | |
ae781774 | 925 | return ret; |
bc1fc6d8 EB |
926 | out_kfree: |
927 | kfree(iter); | |
928 | goto out; | |
929 | } | |
930 | ||
931 | static int sysvipc_proc_release(struct inode *inode, struct file *file) | |
932 | { | |
933 | struct seq_file *seq = file->private_data; | |
934 | struct ipc_proc_iter *iter = seq->private; | |
935 | put_ipc_ns(iter->ns); | |
936 | return seq_release_private(inode, file); | |
ae781774 MW |
937 | } |
938 | ||
9a32144e | 939 | static const struct file_operations sysvipc_proc_fops = { |
ae781774 MW |
940 | .open = sysvipc_proc_open, |
941 | .read = seq_read, | |
942 | .llseek = seq_lseek, | |
bc1fc6d8 | 943 | .release = sysvipc_proc_release, |
ae781774 MW |
944 | }; |
945 | #endif /* CONFIG_PROC_FS */ |