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1da177e4 LT |
1 | /* |
2 | * linux/ipc/util.c | |
3 | * Copyright (C) 1992 Krishna Balasubramanian | |
4 | * | |
5 | * Sep 1997 - Call suser() last after "normal" permission checks so we | |
6 | * get BSD style process accounting right. | |
7 | * Occurs in several places in the IPC code. | |
8 | * Chris Evans, <chris@ferret.lmh.ox.ac.uk> | |
9 | * Nov 1999 - ipc helper functions, unified SMP locking | |
624dffcb | 10 | * Manfred Spraul <manfred@colorfullife.com> |
1da177e4 LT |
11 | * Oct 2002 - One lock per IPC id. RCU ipc_free for lock-free grow_ary(). |
12 | * Mingming Cao <cmm@us.ibm.com> | |
073115d6 SG |
13 | * Mar 2006 - support for audit of ipc object properties |
14 | * Dustin Kirkland <dustin.kirkland@us.ibm.com> | |
73ea4130 KK |
15 | * Jun 2006 - namespaces ssupport |
16 | * OpenVZ, SWsoft Inc. | |
17 | * Pavel Emelianov <xemul@openvz.org> | |
05603c44 DB |
18 | * |
19 | * General sysv ipc locking scheme: | |
18ccee26 DB |
20 | * rcu_read_lock() |
21 | * obtain the ipc object (kern_ipc_perm) by looking up the id in an idr | |
22 | * tree. | |
23 | * - perform initial checks (capabilities, auditing and permission, | |
24 | * etc). | |
25 | * - perform read-only operations, such as STAT, INFO commands. | |
26 | * acquire the ipc lock (kern_ipc_perm.lock) through | |
27 | * ipc_lock_object() | |
28 | * - perform data updates, such as SET, RMID commands and | |
29 | * mechanism-specific operations (semop/semtimedop, | |
30 | * msgsnd/msgrcv, shmat/shmdt). | |
31 | * drop the ipc lock, through ipc_unlock_object(). | |
32 | * rcu_read_unlock() | |
33 | * | |
34 | * The ids->rwsem must be taken when: | |
35 | * - creating, removing and iterating the existing entries in ipc | |
36 | * identifier sets. | |
37 | * - iterating through files under /proc/sysvipc/ | |
38 | * | |
39 | * Note that sems have a special fast path that avoids kern_ipc_perm.lock - | |
40 | * see sem_lock(). | |
1da177e4 LT |
41 | */ |
42 | ||
1da177e4 LT |
43 | #include <linux/mm.h> |
44 | #include <linux/shm.h> | |
45 | #include <linux/init.h> | |
46 | #include <linux/msg.h> | |
1da177e4 LT |
47 | #include <linux/vmalloc.h> |
48 | #include <linux/slab.h> | |
8f68fa2d | 49 | #include <linux/notifier.h> |
c59ede7b | 50 | #include <linux/capability.h> |
1da177e4 LT |
51 | #include <linux/highuid.h> |
52 | #include <linux/security.h> | |
53 | #include <linux/rcupdate.h> | |
54 | #include <linux/workqueue.h> | |
ae781774 MW |
55 | #include <linux/seq_file.h> |
56 | #include <linux/proc_fs.h> | |
073115d6 | 57 | #include <linux/audit.h> |
73ea4130 | 58 | #include <linux/nsproxy.h> |
3e148c79 | 59 | #include <linux/rwsem.h> |
b6b337ad | 60 | #include <linux/memory.h> |
ae5e1b22 | 61 | #include <linux/ipc_namespace.h> |
1da177e4 LT |
62 | |
63 | #include <asm/unistd.h> | |
64 | ||
65 | #include "util.h" | |
66 | ||
ae781774 MW |
67 | struct ipc_proc_iface { |
68 | const char *path; | |
69 | const char *header; | |
73ea4130 | 70 | int ids; |
ae781774 MW |
71 | int (*show)(struct seq_file *, void *); |
72 | }; | |
73 | ||
424450c1 ND |
74 | static void ipc_memory_notifier(struct work_struct *work) |
75 | { | |
76 | ipcns_notify(IPCNS_MEMCHANGED); | |
77 | } | |
78 | ||
b6b337ad ND |
79 | static int ipc_memory_callback(struct notifier_block *self, |
80 | unsigned long action, void *arg) | |
81 | { | |
8f68fa2d AM |
82 | static DECLARE_WORK(ipc_memory_wq, ipc_memory_notifier); |
83 | ||
b6b337ad ND |
84 | switch (action) { |
85 | case MEM_ONLINE: /* memory successfully brought online */ | |
86 | case MEM_OFFLINE: /* or offline: it's time to recompute msgmni */ | |
87 | /* | |
88 | * This is done by invoking the ipcns notifier chain with the | |
89 | * IPC_MEMCHANGED event. | |
424450c1 ND |
90 | * In order not to keep the lock on the hotplug memory chain |
91 | * for too long, queue a work item that will, when waken up, | |
92 | * activate the ipcns notification chain. | |
b6b337ad | 93 | */ |
206fa940 | 94 | schedule_work(&ipc_memory_wq); |
b6b337ad ND |
95 | break; |
96 | case MEM_GOING_ONLINE: | |
97 | case MEM_GOING_OFFLINE: | |
98 | case MEM_CANCEL_ONLINE: | |
99 | case MEM_CANCEL_OFFLINE: | |
100 | default: | |
101 | break; | |
102 | } | |
103 | ||
104 | return NOTIFY_OK; | |
105 | } | |
106 | ||
8f68fa2d AM |
107 | static struct notifier_block ipc_memory_nb = { |
108 | .notifier_call = ipc_memory_callback, | |
109 | .priority = IPC_CALLBACK_PRI, | |
110 | }; | |
b6b337ad | 111 | |
1da177e4 | 112 | /** |
8001c858 | 113 | * ipc_init - initialise ipc subsystem |
1da177e4 | 114 | * |
8001c858 DB |
115 | * The various sysv ipc resources (semaphores, messages and shared |
116 | * memory) are initialised. | |
117 | * | |
118 | * A callback routine is registered into the memory hotplug notifier | |
119 | * chain: since msgmni scales to lowmem this callback routine will be | |
120 | * called upon successful memory add / remove to recompute msmgni. | |
1da177e4 | 121 | */ |
1da177e4 LT |
122 | static int __init ipc_init(void) |
123 | { | |
124 | sem_init(); | |
125 | msg_init(); | |
126 | shm_init(); | |
8f68fa2d | 127 | register_hotmemory_notifier(&ipc_memory_nb); |
b6b337ad | 128 | register_ipcns_notifier(&init_ipc_ns); |
1da177e4 LT |
129 | return 0; |
130 | } | |
131 | __initcall(ipc_init); | |
132 | ||
133 | /** | |
8001c858 DB |
134 | * ipc_init_ids - initialise ipc identifiers |
135 | * @ids: ipc identifier set | |
1da177e4 | 136 | * |
8001c858 DB |
137 | * Set up the sequence range to use for the ipc identifier range (limited |
138 | * below IPCMNI) then initialise the ids idr. | |
1da177e4 | 139 | */ |
7ca7e564 | 140 | void ipc_init_ids(struct ipc_ids *ids) |
1da177e4 | 141 | { |
d9a605e4 | 142 | init_rwsem(&ids->rwsem); |
1da177e4 | 143 | |
1da177e4 | 144 | ids->in_use = 0; |
1da177e4 | 145 | ids->seq = 0; |
03f59566 | 146 | ids->next_id = -1; |
1da177e4 LT |
147 | { |
148 | int seq_limit = INT_MAX/SEQ_MULTIPLIER; | |
4be929be AD |
149 | if (seq_limit > USHRT_MAX) |
150 | ids->seq_max = USHRT_MAX; | |
1da177e4 | 151 | else |
239521f3 | 152 | ids->seq_max = seq_limit; |
1da177e4 LT |
153 | } |
154 | ||
7ca7e564 | 155 | idr_init(&ids->ipcs_idr); |
1da177e4 LT |
156 | } |
157 | ||
ae781774 | 158 | #ifdef CONFIG_PROC_FS |
9a32144e | 159 | static const struct file_operations sysvipc_proc_fops; |
ae781774 | 160 | /** |
8001c858 DB |
161 | * ipc_init_proc_interface - create a proc interface for sysipc types using a seq_file interface. |
162 | * @path: Path in procfs | |
163 | * @header: Banner to be printed at the beginning of the file. | |
164 | * @ids: ipc id table to iterate. | |
165 | * @show: show routine. | |
ae781774 MW |
166 | */ |
167 | void __init ipc_init_proc_interface(const char *path, const char *header, | |
73ea4130 | 168 | int ids, int (*show)(struct seq_file *, void *)) |
ae781774 MW |
169 | { |
170 | struct proc_dir_entry *pde; | |
171 | struct ipc_proc_iface *iface; | |
172 | ||
173 | iface = kmalloc(sizeof(*iface), GFP_KERNEL); | |
174 | if (!iface) | |
175 | return; | |
176 | iface->path = path; | |
177 | iface->header = header; | |
178 | iface->ids = ids; | |
179 | iface->show = show; | |
180 | ||
6a6375db DL |
181 | pde = proc_create_data(path, |
182 | S_IRUGO, /* world readable */ | |
183 | NULL, /* parent dir */ | |
184 | &sysvipc_proc_fops, | |
185 | iface); | |
3ab08fe2 | 186 | if (!pde) |
ae781774 | 187 | kfree(iface); |
ae781774 MW |
188 | } |
189 | #endif | |
190 | ||
1da177e4 | 191 | /** |
8001c858 DB |
192 | * ipc_findkey - find a key in an ipc identifier set |
193 | * @ids: ipc identifier set | |
194 | * @key: key to find | |
1da177e4 | 195 | * |
8001c858 DB |
196 | * Returns the locked pointer to the ipc structure if found or NULL |
197 | * otherwise. If key is found ipc points to the owning ipc structure | |
198 | * | |
199 | * Called with ipc_ids.rwsem held. | |
1da177e4 | 200 | */ |
7748dbfa | 201 | static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key) |
1da177e4 | 202 | { |
7ca7e564 ND |
203 | struct kern_ipc_perm *ipc; |
204 | int next_id; | |
205 | int total; | |
1da177e4 | 206 | |
7ca7e564 ND |
207 | for (total = 0, next_id = 0; total < ids->in_use; next_id++) { |
208 | ipc = idr_find(&ids->ipcs_idr, next_id); | |
209 | ||
210 | if (ipc == NULL) | |
1da177e4 | 211 | continue; |
7ca7e564 ND |
212 | |
213 | if (ipc->key != key) { | |
214 | total++; | |
215 | continue; | |
216 | } | |
217 | ||
32a27500 DB |
218 | rcu_read_lock(); |
219 | ipc_lock_object(ipc); | |
7ca7e564 | 220 | return ipc; |
1da177e4 | 221 | } |
7ca7e564 ND |
222 | |
223 | return NULL; | |
1da177e4 LT |
224 | } |
225 | ||
7ca7e564 | 226 | /** |
8001c858 DB |
227 | * ipc_get_maxid - get the last assigned id |
228 | * @ids: ipc identifier set | |
7ca7e564 | 229 | * |
8001c858 | 230 | * Called with ipc_ids.rwsem held. |
1da177e4 | 231 | */ |
7ca7e564 ND |
232 | int ipc_get_maxid(struct ipc_ids *ids) |
233 | { | |
234 | struct kern_ipc_perm *ipc; | |
235 | int max_id = -1; | |
236 | int total, id; | |
237 | ||
238 | if (ids->in_use == 0) | |
239 | return -1; | |
1da177e4 | 240 | |
7ca7e564 ND |
241 | if (ids->in_use == IPCMNI) |
242 | return IPCMNI - 1; | |
243 | ||
244 | /* Look for the last assigned id */ | |
245 | total = 0; | |
246 | for (id = 0; id < IPCMNI && total < ids->in_use; id++) { | |
247 | ipc = idr_find(&ids->ipcs_idr, id); | |
248 | if (ipc != NULL) { | |
249 | max_id = id; | |
250 | total++; | |
251 | } | |
252 | } | |
253 | return max_id; | |
1da177e4 LT |
254 | } |
255 | ||
256 | /** | |
8001c858 DB |
257 | * ipc_addid - add an ipc identifier |
258 | * @ids: ipc identifier set | |
259 | * @new: new ipc permission set | |
260 | * @size: limit for the number of used ids | |
1da177e4 | 261 | * |
8001c858 DB |
262 | * Add an entry 'new' to the ipc ids idr. The permissions object is |
263 | * initialised and the first free entry is set up and the id assigned | |
264 | * is returned. The 'new' entry is returned in a locked state on success. | |
265 | * On failure the entry is not locked and a negative err-code is returned. | |
1da177e4 | 266 | * |
8001c858 | 267 | * Called with writer ipc_ids.rwsem held. |
1da177e4 | 268 | */ |
239521f3 | 269 | int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int size) |
1da177e4 | 270 | { |
1efdb69b EB |
271 | kuid_t euid; |
272 | kgid_t egid; | |
54924ea3 | 273 | int id; |
03f59566 | 274 | int next_id = ids->next_id; |
1da177e4 | 275 | |
7ca7e564 ND |
276 | if (size > IPCMNI) |
277 | size = IPCMNI; | |
278 | ||
279 | if (ids->in_use >= size) | |
283bb7fa | 280 | return -ENOSPC; |
7ca7e564 | 281 | |
54924ea3 TH |
282 | idr_preload(GFP_KERNEL); |
283 | ||
e00b4ff7 | 284 | spin_lock_init(&new->lock); |
72a8ff2f | 285 | new->deleted = false; |
e00b4ff7 ND |
286 | rcu_read_lock(); |
287 | spin_lock(&new->lock); | |
288 | ||
54924ea3 TH |
289 | id = idr_alloc(&ids->ipcs_idr, new, |
290 | (next_id < 0) ? 0 : ipcid_to_idx(next_id), 0, | |
291 | GFP_NOWAIT); | |
292 | idr_preload_end(); | |
293 | if (id < 0) { | |
e00b4ff7 ND |
294 | spin_unlock(&new->lock); |
295 | rcu_read_unlock(); | |
54924ea3 | 296 | return id; |
e00b4ff7 | 297 | } |
7ca7e564 | 298 | |
1da177e4 | 299 | ids->in_use++; |
1da177e4 | 300 | |
414c0708 DH |
301 | current_euid_egid(&euid, &egid); |
302 | new->cuid = new->uid = euid; | |
303 | new->gid = new->cgid = egid; | |
1da177e4 | 304 | |
03f59566 SK |
305 | if (next_id < 0) { |
306 | new->seq = ids->seq++; | |
307 | if (ids->seq > ids->seq_max) | |
308 | ids->seq = 0; | |
309 | } else { | |
310 | new->seq = ipcid_to_seqx(next_id); | |
311 | ids->next_id = -1; | |
312 | } | |
1da177e4 | 313 | |
48dea404 | 314 | new->id = ipc_buildid(id, new->seq); |
1da177e4 LT |
315 | return id; |
316 | } | |
317 | ||
7748dbfa | 318 | /** |
8001c858 DB |
319 | * ipcget_new - create a new ipc object |
320 | * @ns: ipc namespace | |
321 | * @ids: ipc identifer set | |
322 | * @ops: the actual creation routine to call | |
323 | * @params: its parameters | |
324 | * | |
325 | * This routine is called by sys_msgget, sys_semget() and sys_shmget() | |
326 | * when the key is IPC_PRIVATE. | |
7748dbfa | 327 | */ |
b2d75cdd | 328 | static int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids, |
7748dbfa ND |
329 | struct ipc_ops *ops, struct ipc_params *params) |
330 | { | |
331 | int err; | |
7748dbfa | 332 | |
d9a605e4 | 333 | down_write(&ids->rwsem); |
7748dbfa | 334 | err = ops->getnew(ns, params); |
d9a605e4 | 335 | up_write(&ids->rwsem); |
7748dbfa ND |
336 | return err; |
337 | } | |
338 | ||
339 | /** | |
8001c858 DB |
340 | * ipc_check_perms - check security and permissions for an ipc object |
341 | * @ns: ipc namespace | |
342 | * @ipcp: ipc permission set | |
343 | * @ops: the actual security routine to call | |
344 | * @params: its parameters | |
f4566f04 | 345 | * |
8001c858 DB |
346 | * This routine is called by sys_msgget(), sys_semget() and sys_shmget() |
347 | * when the key is not IPC_PRIVATE and that key already exists in the | |
348 | * ds IDR. | |
f4566f04 | 349 | * |
8001c858 | 350 | * On success, the ipc id is returned. |
f4566f04 | 351 | * |
8001c858 | 352 | * It is called with ipc_ids.rwsem and ipcp->lock held. |
7748dbfa | 353 | */ |
b0e77598 SH |
354 | static int ipc_check_perms(struct ipc_namespace *ns, |
355 | struct kern_ipc_perm *ipcp, | |
356 | struct ipc_ops *ops, | |
357 | struct ipc_params *params) | |
7748dbfa ND |
358 | { |
359 | int err; | |
360 | ||
b0e77598 | 361 | if (ipcperms(ns, ipcp, params->flg)) |
7748dbfa ND |
362 | err = -EACCES; |
363 | else { | |
364 | err = ops->associate(ipcp, params->flg); | |
365 | if (!err) | |
366 | err = ipcp->id; | |
367 | } | |
368 | ||
369 | return err; | |
370 | } | |
371 | ||
372 | /** | |
8001c858 DB |
373 | * ipcget_public - get an ipc object or create a new one |
374 | * @ns: ipc namespace | |
375 | * @ids: ipc identifer set | |
376 | * @ops: the actual creation routine to call | |
377 | * @params: its parameters | |
378 | * | |
379 | * This routine is called by sys_msgget, sys_semget() and sys_shmget() | |
380 | * when the key is not IPC_PRIVATE. | |
381 | * It adds a new entry if the key is not found and does some permission | |
382 | * / security checkings if the key is found. | |
383 | * | |
384 | * On success, the ipc id is returned. | |
7748dbfa | 385 | */ |
b2d75cdd | 386 | static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids, |
7748dbfa ND |
387 | struct ipc_ops *ops, struct ipc_params *params) |
388 | { | |
389 | struct kern_ipc_perm *ipcp; | |
390 | int flg = params->flg; | |
391 | int err; | |
7748dbfa | 392 | |
3e148c79 ND |
393 | /* |
394 | * Take the lock as a writer since we are potentially going to add | |
395 | * a new entry + read locks are not "upgradable" | |
396 | */ | |
d9a605e4 | 397 | down_write(&ids->rwsem); |
7748dbfa ND |
398 | ipcp = ipc_findkey(ids, params->key); |
399 | if (ipcp == NULL) { | |
400 | /* key not used */ | |
401 | if (!(flg & IPC_CREAT)) | |
402 | err = -ENOENT; | |
7748dbfa ND |
403 | else |
404 | err = ops->getnew(ns, params); | |
405 | } else { | |
406 | /* ipc object has been locked by ipc_findkey() */ | |
407 | ||
408 | if (flg & IPC_CREAT && flg & IPC_EXCL) | |
409 | err = -EEXIST; | |
410 | else { | |
411 | err = 0; | |
412 | if (ops->more_checks) | |
413 | err = ops->more_checks(ipcp, params); | |
414 | if (!err) | |
f4566f04 ND |
415 | /* |
416 | * ipc_check_perms returns the IPC id on | |
417 | * success | |
418 | */ | |
b0e77598 | 419 | err = ipc_check_perms(ns, ipcp, ops, params); |
7748dbfa ND |
420 | } |
421 | ipc_unlock(ipcp); | |
422 | } | |
d9a605e4 | 423 | up_write(&ids->rwsem); |
7748dbfa ND |
424 | |
425 | return err; | |
426 | } | |
427 | ||
428 | ||
1da177e4 | 429 | /** |
8001c858 DB |
430 | * ipc_rmid - remove an ipc identifier |
431 | * @ids: ipc identifier set | |
432 | * @ipcp: ipc perm structure containing the identifier to remove | |
1da177e4 | 433 | * |
8001c858 DB |
434 | * ipc_ids.rwsem (as a writer) and the spinlock for this ID are held |
435 | * before this function is called, and remain locked on the exit. | |
1da177e4 | 436 | */ |
7ca7e564 | 437 | void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp) |
1da177e4 | 438 | { |
ce621f5b | 439 | int lid = ipcid_to_idx(ipcp->id); |
7ca7e564 ND |
440 | |
441 | idr_remove(&ids->ipcs_idr, lid); | |
1da177e4 | 442 | ids->in_use--; |
72a8ff2f | 443 | ipcp->deleted = true; |
1da177e4 LT |
444 | } |
445 | ||
446 | /** | |
8001c858 DB |
447 | * ipc_alloc - allocate ipc space |
448 | * @size: size desired | |
1da177e4 | 449 | * |
8001c858 DB |
450 | * Allocate memory from the appropriate pools and return a pointer to it. |
451 | * NULL is returned if the allocation fails | |
1da177e4 | 452 | */ |
6062a8dc | 453 | void *ipc_alloc(int size) |
1da177e4 | 454 | { |
6062a8dc | 455 | void *out; |
239521f3 | 456 | if (size > PAGE_SIZE) |
1da177e4 LT |
457 | out = vmalloc(size); |
458 | else | |
459 | out = kmalloc(size, GFP_KERNEL); | |
460 | return out; | |
461 | } | |
462 | ||
463 | /** | |
8001c858 DB |
464 | * ipc_free - free ipc space |
465 | * @ptr: pointer returned by ipc_alloc | |
466 | * @size: size of block | |
1da177e4 | 467 | * |
8001c858 DB |
468 | * Free a block created with ipc_alloc(). The caller must know the size |
469 | * used in the allocation call. | |
1da177e4 | 470 | */ |
239521f3 | 471 | void ipc_free(void *ptr, int size) |
1da177e4 | 472 | { |
239521f3 | 473 | if (size > PAGE_SIZE) |
1da177e4 LT |
474 | vfree(ptr); |
475 | else | |
476 | kfree(ptr); | |
477 | } | |
478 | ||
1da177e4 | 479 | /** |
8001c858 DB |
480 | * ipc_rcu_alloc - allocate ipc and rcu space |
481 | * @size: size desired | |
1da177e4 | 482 | * |
8001c858 DB |
483 | * Allocate memory for the rcu header structure + the object. |
484 | * Returns the pointer to the object or NULL upon failure. | |
1da177e4 | 485 | */ |
6062a8dc | 486 | void *ipc_rcu_alloc(int size) |
1da177e4 | 487 | { |
6062a8dc | 488 | /* |
600fe975 | 489 | * We prepend the allocation with the rcu struct |
1da177e4 | 490 | */ |
600fe975 AV |
491 | struct ipc_rcu *out = ipc_alloc(sizeof(struct ipc_rcu) + size); |
492 | if (unlikely(!out)) | |
493 | return NULL; | |
494 | atomic_set(&out->refcount, 1); | |
196aa013 | 495 | return out + 1; |
1da177e4 LT |
496 | } |
497 | ||
6062a8dc | 498 | int ipc_rcu_getref(void *ptr) |
1da177e4 | 499 | { |
196aa013 MS |
500 | struct ipc_rcu *p = ((struct ipc_rcu *)ptr) - 1; |
501 | ||
502 | return atomic_inc_not_zero(&p->refcount); | |
65f27f38 DH |
503 | } |
504 | ||
53dad6d3 | 505 | void ipc_rcu_putref(void *ptr, void (*func)(struct rcu_head *head)) |
1da177e4 | 506 | { |
196aa013 | 507 | struct ipc_rcu *p = ((struct ipc_rcu *)ptr) - 1; |
600fe975 AV |
508 | |
509 | if (!atomic_dec_and_test(&p->refcount)) | |
1da177e4 LT |
510 | return; |
511 | ||
53dad6d3 DB |
512 | call_rcu(&p->rcu, func); |
513 | } | |
514 | ||
515 | void ipc_rcu_free(struct rcu_head *head) | |
516 | { | |
517 | struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu); | |
518 | ||
519 | if (is_vmalloc_addr(p)) | |
520 | vfree(p); | |
521 | else | |
522 | kfree(p); | |
1da177e4 LT |
523 | } |
524 | ||
525 | /** | |
8001c858 DB |
526 | * ipcperms - check ipc permissions |
527 | * @ns: ipc namespace | |
528 | * @ipcp: ipc permission set | |
529 | * @flag: desired permission set | |
1da177e4 | 530 | * |
8001c858 DB |
531 | * Check user, group, other permissions for access |
532 | * to ipc resources. return 0 if allowed | |
b0e77598 | 533 | * |
8001c858 | 534 | * @flag will most probably be 0 or S_...UGO from <linux/stat.h> |
1da177e4 | 535 | */ |
b0e77598 SH |
536 | int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flag) |
537 | { | |
1efdb69b | 538 | kuid_t euid = current_euid(); |
a33e6751 | 539 | int requested_mode, granted_mode; |
1da177e4 | 540 | |
a33e6751 | 541 | audit_ipc_obj(ipcp); |
1da177e4 LT |
542 | requested_mode = (flag >> 6) | (flag >> 3) | flag; |
543 | granted_mode = ipcp->mode; | |
1efdb69b EB |
544 | if (uid_eq(euid, ipcp->cuid) || |
545 | uid_eq(euid, ipcp->uid)) | |
1da177e4 LT |
546 | granted_mode >>= 6; |
547 | else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid)) | |
548 | granted_mode >>= 3; | |
549 | /* is there some bit set in requested_mode but not in granted_mode? */ | |
550 | if ((requested_mode & ~granted_mode & 0007) && | |
b0e77598 | 551 | !ns_capable(ns->user_ns, CAP_IPC_OWNER)) |
1da177e4 LT |
552 | return -1; |
553 | ||
554 | return security_ipc_permission(ipcp, flag); | |
555 | } | |
556 | ||
557 | /* | |
558 | * Functions to convert between the kern_ipc_perm structure and the | |
559 | * old/new ipc_perm structures | |
560 | */ | |
561 | ||
562 | /** | |
8001c858 DB |
563 | * kernel_to_ipc64_perm - convert kernel ipc permissions to user |
564 | * @in: kernel permissions | |
565 | * @out: new style ipc permissions | |
1da177e4 | 566 | * |
8001c858 DB |
567 | * Turn the kernel object @in into a set of permissions descriptions |
568 | * for returning to userspace (@out). | |
1da177e4 | 569 | */ |
239521f3 | 570 | void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out) |
1da177e4 LT |
571 | { |
572 | out->key = in->key; | |
1efdb69b EB |
573 | out->uid = from_kuid_munged(current_user_ns(), in->uid); |
574 | out->gid = from_kgid_munged(current_user_ns(), in->gid); | |
575 | out->cuid = from_kuid_munged(current_user_ns(), in->cuid); | |
576 | out->cgid = from_kgid_munged(current_user_ns(), in->cgid); | |
1da177e4 LT |
577 | out->mode = in->mode; |
578 | out->seq = in->seq; | |
579 | } | |
580 | ||
581 | /** | |
8001c858 DB |
582 | * ipc64_perm_to_ipc_perm - convert new ipc permissions to old |
583 | * @in: new style ipc permissions | |
584 | * @out: old style ipc permissions | |
1da177e4 | 585 | * |
8001c858 DB |
586 | * Turn the new style permissions object @in into a compatibility |
587 | * object and store it into the @out pointer. | |
1da177e4 | 588 | */ |
239521f3 | 589 | void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out) |
1da177e4 LT |
590 | { |
591 | out->key = in->key; | |
592 | SET_UID(out->uid, in->uid); | |
593 | SET_GID(out->gid, in->gid); | |
594 | SET_UID(out->cuid, in->cuid); | |
595 | SET_GID(out->cgid, in->cgid); | |
596 | out->mode = in->mode; | |
597 | out->seq = in->seq; | |
598 | } | |
599 | ||
4d2bff5e DB |
600 | /** |
601 | * ipc_obtain_object | |
602 | * @ids: ipc identifier set | |
603 | * @id: ipc id to look for | |
604 | * | |
605 | * Look for an id in the ipc ids idr and return associated ipc object. | |
606 | * | |
607 | * Call inside the RCU critical section. | |
608 | * The ipc object is *not* locked on exit. | |
609 | */ | |
610 | struct kern_ipc_perm *ipc_obtain_object(struct ipc_ids *ids, int id) | |
611 | { | |
612 | struct kern_ipc_perm *out; | |
613 | int lid = ipcid_to_idx(id); | |
614 | ||
615 | out = idr_find(&ids->ipcs_idr, lid); | |
616 | if (!out) | |
617 | return ERR_PTR(-EINVAL); | |
618 | ||
619 | return out; | |
620 | } | |
621 | ||
f4566f04 | 622 | /** |
8001c858 DB |
623 | * ipc_lock - lock an ipc structure without rwsem held |
624 | * @ids: ipc identifier set | |
f4566f04 ND |
625 | * @id: ipc id to look for |
626 | * | |
627 | * Look for an id in the ipc ids idr and lock the associated ipc object. | |
628 | * | |
4d2bff5e | 629 | * The ipc object is locked on successful exit. |
f4566f04 | 630 | */ |
7ca7e564 | 631 | struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id) |
1da177e4 | 632 | { |
7ca7e564 | 633 | struct kern_ipc_perm *out; |
1da177e4 LT |
634 | |
635 | rcu_read_lock(); | |
4d2bff5e DB |
636 | out = ipc_obtain_object(ids, id); |
637 | if (IS_ERR(out)) | |
638 | goto err1; | |
7ca7e564 | 639 | |
1da177e4 | 640 | spin_lock(&out->lock); |
4d2bff5e | 641 | |
1da177e4 LT |
642 | /* ipc_rmid() may have already freed the ID while ipc_lock |
643 | * was spinning: here verify that the structure is still valid | |
644 | */ | |
72a8ff2f | 645 | if (ipc_valid_object(out)) |
4d2bff5e DB |
646 | return out; |
647 | ||
648 | spin_unlock(&out->lock); | |
649 | out = ERR_PTR(-EINVAL); | |
650 | err1: | |
651 | rcu_read_unlock(); | |
652 | return out; | |
653 | } | |
7ca7e564 | 654 | |
4d2bff5e DB |
655 | /** |
656 | * ipc_obtain_object_check | |
657 | * @ids: ipc identifier set | |
658 | * @id: ipc id to look for | |
659 | * | |
660 | * Similar to ipc_obtain_object() but also checks | |
661 | * the ipc object reference counter. | |
662 | * | |
663 | * Call inside the RCU critical section. | |
664 | * The ipc object is *not* locked on exit. | |
665 | */ | |
666 | struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id) | |
667 | { | |
668 | struct kern_ipc_perm *out = ipc_obtain_object(ids, id); | |
669 | ||
670 | if (IS_ERR(out)) | |
671 | goto out; | |
672 | ||
673 | if (ipc_checkid(out, id)) | |
674 | return ERR_PTR(-EIDRM); | |
675 | out: | |
1da177e4 LT |
676 | return out; |
677 | } | |
678 | ||
b2d75cdd PE |
679 | /** |
680 | * ipcget - Common sys_*get() code | |
8001c858 DB |
681 | * @ns: namsepace |
682 | * @ids: ipc identifier set | |
683 | * @ops: operations to be called on ipc object creation, permission checks | |
684 | * and further checks | |
685 | * @params: the parameters needed by the previous operations. | |
b2d75cdd PE |
686 | * |
687 | * Common routine called by sys_msgget(), sys_semget() and sys_shmget(). | |
688 | */ | |
689 | int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, | |
690 | struct ipc_ops *ops, struct ipc_params *params) | |
691 | { | |
692 | if (params->key == IPC_PRIVATE) | |
693 | return ipcget_new(ns, ids, ops, params); | |
694 | else | |
695 | return ipcget_public(ns, ids, ops, params); | |
696 | } | |
697 | ||
8f4a3809 | 698 | /** |
8001c858 | 699 | * ipc_update_perm - update the permissions of an ipc object |
8f4a3809 PP |
700 | * @in: the permission given as input. |
701 | * @out: the permission of the ipc to set. | |
702 | */ | |
1efdb69b | 703 | int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out) |
8f4a3809 | 704 | { |
1efdb69b EB |
705 | kuid_t uid = make_kuid(current_user_ns(), in->uid); |
706 | kgid_t gid = make_kgid(current_user_ns(), in->gid); | |
707 | if (!uid_valid(uid) || !gid_valid(gid)) | |
708 | return -EINVAL; | |
709 | ||
710 | out->uid = uid; | |
711 | out->gid = gid; | |
8f4a3809 PP |
712 | out->mode = (out->mode & ~S_IRWXUGO) |
713 | | (in->mode & S_IRWXUGO); | |
1efdb69b EB |
714 | |
715 | return 0; | |
8f4a3809 PP |
716 | } |
717 | ||
a5f75e7f | 718 | /** |
3b1c4ad3 | 719 | * ipcctl_pre_down_nolock - retrieve an ipc and check permissions for some IPC_XXX cmd |
8001c858 | 720 | * @ns: ipc namespace |
a5f75e7f PP |
721 | * @ids: the table of ids where to look for the ipc |
722 | * @id: the id of the ipc to retrieve | |
723 | * @cmd: the cmd to check | |
724 | * @perm: the permission to set | |
725 | * @extra_perm: one extra permission parameter used by msq | |
726 | * | |
727 | * This function does some common audit and permissions check for some IPC_XXX | |
728 | * cmd and is called from semctl_down, shmctl_down and msgctl_down. | |
729 | * It must be called without any lock held and | |
730 | * - retrieves the ipc with the given id in the given table. | |
731 | * - performs some audit and permission check, depending on the given cmd | |
3b1c4ad3 | 732 | * - returns a pointer to the ipc object or otherwise, the corresponding error. |
7b4cc5d8 | 733 | * |
d9a605e4 | 734 | * Call holding the both the rwsem and the rcu read lock. |
a5f75e7f | 735 | */ |
444d0f62 | 736 | struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns, |
3b1c4ad3 DB |
737 | struct ipc_ids *ids, int id, int cmd, |
738 | struct ipc64_perm *perm, int extra_perm) | |
444d0f62 | 739 | { |
1efdb69b | 740 | kuid_t euid; |
444d0f62 DB |
741 | int err = -EPERM; |
742 | struct kern_ipc_perm *ipcp; | |
a5f75e7f | 743 | |
444d0f62 | 744 | ipcp = ipc_obtain_object_check(ids, id); |
a5f75e7f PP |
745 | if (IS_ERR(ipcp)) { |
746 | err = PTR_ERR(ipcp); | |
7b4cc5d8 | 747 | goto err; |
a5f75e7f PP |
748 | } |
749 | ||
a33e6751 | 750 | audit_ipc_obj(ipcp); |
e816f370 AV |
751 | if (cmd == IPC_SET) |
752 | audit_ipc_set_perm(extra_perm, perm->uid, | |
444d0f62 | 753 | perm->gid, perm->mode); |
414c0708 DH |
754 | |
755 | euid = current_euid(); | |
1efdb69b | 756 | if (uid_eq(euid, ipcp->cuid) || uid_eq(euid, ipcp->uid) || |
b0e77598 | 757 | ns_capable(ns->user_ns, CAP_SYS_ADMIN)) |
7b4cc5d8 DB |
758 | return ipcp; /* successful lookup */ |
759 | err: | |
a5f75e7f PP |
760 | return ERR_PTR(err); |
761 | } | |
762 | ||
c1d7e01d | 763 | #ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION |
1da177e4 LT |
764 | |
765 | ||
766 | /** | |
8001c858 DB |
767 | * ipc_parse_version - ipc call version |
768 | * @cmd: pointer to command | |
1da177e4 | 769 | * |
8001c858 DB |
770 | * Return IPC_64 for new style IPC and IPC_OLD for old style IPC. |
771 | * The @cmd value is turned from an encoding command and version into | |
772 | * just the command code. | |
1da177e4 | 773 | */ |
239521f3 | 774 | int ipc_parse_version(int *cmd) |
1da177e4 LT |
775 | { |
776 | if (*cmd & IPC_64) { | |
777 | *cmd ^= IPC_64; | |
778 | return IPC_64; | |
779 | } else { | |
780 | return IPC_OLD; | |
781 | } | |
782 | } | |
783 | ||
c1d7e01d | 784 | #endif /* CONFIG_ARCH_WANT_IPC_PARSE_VERSION */ |
ae781774 MW |
785 | |
786 | #ifdef CONFIG_PROC_FS | |
bc1fc6d8 EB |
787 | struct ipc_proc_iter { |
788 | struct ipc_namespace *ns; | |
789 | struct ipc_proc_iface *iface; | |
790 | }; | |
791 | ||
7ca7e564 ND |
792 | /* |
793 | * This routine locks the ipc structure found at least at position pos. | |
794 | */ | |
b524b9ad AB |
795 | static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos, |
796 | loff_t *new_pos) | |
ae781774 | 797 | { |
7ca7e564 ND |
798 | struct kern_ipc_perm *ipc; |
799 | int total, id; | |
73ea4130 | 800 | |
7ca7e564 ND |
801 | total = 0; |
802 | for (id = 0; id < pos && total < ids->in_use; id++) { | |
803 | ipc = idr_find(&ids->ipcs_idr, id); | |
804 | if (ipc != NULL) | |
805 | total++; | |
806 | } | |
ae781774 | 807 | |
7ca7e564 ND |
808 | if (total >= ids->in_use) |
809 | return NULL; | |
ae781774 | 810 | |
239521f3 | 811 | for (; pos < IPCMNI; pos++) { |
7ca7e564 ND |
812 | ipc = idr_find(&ids->ipcs_idr, pos); |
813 | if (ipc != NULL) { | |
814 | *new_pos = pos + 1; | |
32a27500 DB |
815 | rcu_read_lock(); |
816 | ipc_lock_object(ipc); | |
ae781774 MW |
817 | return ipc; |
818 | } | |
819 | } | |
820 | ||
821 | /* Out of range - return NULL to terminate iteration */ | |
822 | return NULL; | |
823 | } | |
824 | ||
7ca7e564 ND |
825 | static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos) |
826 | { | |
827 | struct ipc_proc_iter *iter = s->private; | |
828 | struct ipc_proc_iface *iface = iter->iface; | |
829 | struct kern_ipc_perm *ipc = it; | |
830 | ||
831 | /* If we had an ipc id locked before, unlock it */ | |
832 | if (ipc && ipc != SEQ_START_TOKEN) | |
833 | ipc_unlock(ipc); | |
834 | ||
ed2ddbf8 | 835 | return sysvipc_find_ipc(&iter->ns->ids[iface->ids], *pos, pos); |
7ca7e564 ND |
836 | } |
837 | ||
ae781774 | 838 | /* |
f4566f04 ND |
839 | * File positions: pos 0 -> header, pos n -> ipc id = n - 1. |
840 | * SeqFile iterator: iterator value locked ipc pointer or SEQ_TOKEN_START. | |
ae781774 MW |
841 | */ |
842 | static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos) | |
843 | { | |
bc1fc6d8 EB |
844 | struct ipc_proc_iter *iter = s->private; |
845 | struct ipc_proc_iface *iface = iter->iface; | |
73ea4130 KK |
846 | struct ipc_ids *ids; |
847 | ||
ed2ddbf8 | 848 | ids = &iter->ns->ids[iface->ids]; |
ae781774 MW |
849 | |
850 | /* | |
851 | * Take the lock - this will be released by the corresponding | |
852 | * call to stop(). | |
853 | */ | |
d9a605e4 | 854 | down_read(&ids->rwsem); |
ae781774 MW |
855 | |
856 | /* pos < 0 is invalid */ | |
857 | if (*pos < 0) | |
858 | return NULL; | |
859 | ||
860 | /* pos == 0 means header */ | |
861 | if (*pos == 0) | |
862 | return SEQ_START_TOKEN; | |
863 | ||
864 | /* Find the (pos-1)th ipc */ | |
7ca7e564 | 865 | return sysvipc_find_ipc(ids, *pos - 1, pos); |
ae781774 MW |
866 | } |
867 | ||
868 | static void sysvipc_proc_stop(struct seq_file *s, void *it) | |
869 | { | |
870 | struct kern_ipc_perm *ipc = it; | |
bc1fc6d8 EB |
871 | struct ipc_proc_iter *iter = s->private; |
872 | struct ipc_proc_iface *iface = iter->iface; | |
73ea4130 | 873 | struct ipc_ids *ids; |
ae781774 | 874 | |
f4566f04 | 875 | /* If we had a locked structure, release it */ |
ae781774 MW |
876 | if (ipc && ipc != SEQ_START_TOKEN) |
877 | ipc_unlock(ipc); | |
878 | ||
ed2ddbf8 | 879 | ids = &iter->ns->ids[iface->ids]; |
ae781774 | 880 | /* Release the lock we took in start() */ |
d9a605e4 | 881 | up_read(&ids->rwsem); |
ae781774 MW |
882 | } |
883 | ||
884 | static int sysvipc_proc_show(struct seq_file *s, void *it) | |
885 | { | |
bc1fc6d8 EB |
886 | struct ipc_proc_iter *iter = s->private; |
887 | struct ipc_proc_iface *iface = iter->iface; | |
ae781774 MW |
888 | |
889 | if (it == SEQ_START_TOKEN) | |
890 | return seq_puts(s, iface->header); | |
891 | ||
892 | return iface->show(s, it); | |
893 | } | |
894 | ||
88e9d34c | 895 | static const struct seq_operations sysvipc_proc_seqops = { |
ae781774 MW |
896 | .start = sysvipc_proc_start, |
897 | .stop = sysvipc_proc_stop, | |
898 | .next = sysvipc_proc_next, | |
899 | .show = sysvipc_proc_show, | |
900 | }; | |
901 | ||
bc1fc6d8 EB |
902 | static int sysvipc_proc_open(struct inode *inode, struct file *file) |
903 | { | |
ae781774 MW |
904 | int ret; |
905 | struct seq_file *seq; | |
bc1fc6d8 EB |
906 | struct ipc_proc_iter *iter; |
907 | ||
908 | ret = -ENOMEM; | |
909 | iter = kmalloc(sizeof(*iter), GFP_KERNEL); | |
910 | if (!iter) | |
911 | goto out; | |
ae781774 MW |
912 | |
913 | ret = seq_open(file, &sysvipc_proc_seqops); | |
8dc5cd04 DB |
914 | if (ret) { |
915 | kfree(iter); | |
916 | goto out; | |
917 | } | |
bc1fc6d8 EB |
918 | |
919 | seq = file->private_data; | |
920 | seq->private = iter; | |
921 | ||
d9dda78b | 922 | iter->iface = PDE_DATA(inode); |
bc1fc6d8 EB |
923 | iter->ns = get_ipc_ns(current->nsproxy->ipc_ns); |
924 | out: | |
ae781774 | 925 | return ret; |
bc1fc6d8 EB |
926 | } |
927 | ||
928 | static int sysvipc_proc_release(struct inode *inode, struct file *file) | |
929 | { | |
930 | struct seq_file *seq = file->private_data; | |
931 | struct ipc_proc_iter *iter = seq->private; | |
932 | put_ipc_ns(iter->ns); | |
933 | return seq_release_private(inode, file); | |
ae781774 MW |
934 | } |
935 | ||
9a32144e | 936 | static const struct file_operations sysvipc_proc_fops = { |
ae781774 MW |
937 | .open = sysvipc_proc_open, |
938 | .read = seq_read, | |
939 | .llseek = seq_lseek, | |
bc1fc6d8 | 940 | .release = sysvipc_proc_release, |
ae781774 MW |
941 | }; |
942 | #endif /* CONFIG_PROC_FS */ |