Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/ipc/util.c | |
3 | * Copyright (C) 1992 Krishna Balasubramanian | |
4 | * | |
5 | * Sep 1997 - Call suser() last after "normal" permission checks so we | |
6 | * get BSD style process accounting right. | |
7 | * Occurs in several places in the IPC code. | |
8 | * Chris Evans, <chris@ferret.lmh.ox.ac.uk> | |
9 | * Nov 1999 - ipc helper functions, unified SMP locking | |
624dffcb | 10 | * Manfred Spraul <manfred@colorfullife.com> |
1da177e4 LT |
11 | * Oct 2002 - One lock per IPC id. RCU ipc_free for lock-free grow_ary(). |
12 | * Mingming Cao <cmm@us.ibm.com> | |
073115d6 SG |
13 | * Mar 2006 - support for audit of ipc object properties |
14 | * Dustin Kirkland <dustin.kirkland@us.ibm.com> | |
73ea4130 KK |
15 | * Jun 2006 - namespaces ssupport |
16 | * OpenVZ, SWsoft Inc. | |
17 | * Pavel Emelianov <xemul@openvz.org> | |
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); | |
186 | if (!pde) { | |
ae781774 MW |
187 | kfree(iface); |
188 | } | |
189 | } | |
190 | #endif | |
191 | ||
1da177e4 | 192 | /** |
8001c858 DB |
193 | * ipc_findkey - find a key in an ipc identifier set |
194 | * @ids: ipc identifier set | |
195 | * @key: key to find | |
1da177e4 | 196 | * |
8001c858 DB |
197 | * Returns the locked pointer to the ipc structure if found or NULL |
198 | * otherwise. If key is found ipc points to the owning ipc structure | |
199 | * | |
200 | * Called with ipc_ids.rwsem held. | |
1da177e4 | 201 | */ |
7748dbfa | 202 | static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key) |
1da177e4 | 203 | { |
7ca7e564 ND |
204 | struct kern_ipc_perm *ipc; |
205 | int next_id; | |
206 | int total; | |
1da177e4 | 207 | |
7ca7e564 ND |
208 | for (total = 0, next_id = 0; total < ids->in_use; next_id++) { |
209 | ipc = idr_find(&ids->ipcs_idr, next_id); | |
210 | ||
211 | if (ipc == NULL) | |
1da177e4 | 212 | continue; |
7ca7e564 ND |
213 | |
214 | if (ipc->key != key) { | |
215 | total++; | |
216 | continue; | |
217 | } | |
218 | ||
32a27500 DB |
219 | rcu_read_lock(); |
220 | ipc_lock_object(ipc); | |
7ca7e564 | 221 | return ipc; |
1da177e4 | 222 | } |
7ca7e564 ND |
223 | |
224 | return NULL; | |
1da177e4 LT |
225 | } |
226 | ||
7ca7e564 | 227 | /** |
8001c858 DB |
228 | * ipc_get_maxid - get the last assigned id |
229 | * @ids: ipc identifier set | |
7ca7e564 | 230 | * |
8001c858 | 231 | * Called with ipc_ids.rwsem held. |
1da177e4 | 232 | */ |
7ca7e564 ND |
233 | int ipc_get_maxid(struct ipc_ids *ids) |
234 | { | |
235 | struct kern_ipc_perm *ipc; | |
236 | int max_id = -1; | |
237 | int total, id; | |
238 | ||
239 | if (ids->in_use == 0) | |
240 | return -1; | |
1da177e4 | 241 | |
7ca7e564 ND |
242 | if (ids->in_use == IPCMNI) |
243 | return IPCMNI - 1; | |
244 | ||
245 | /* Look for the last assigned id */ | |
246 | total = 0; | |
247 | for (id = 0; id < IPCMNI && total < ids->in_use; id++) { | |
248 | ipc = idr_find(&ids->ipcs_idr, id); | |
249 | if (ipc != NULL) { | |
250 | max_id = id; | |
251 | total++; | |
252 | } | |
253 | } | |
254 | return max_id; | |
1da177e4 LT |
255 | } |
256 | ||
257 | /** | |
8001c858 DB |
258 | * ipc_addid - add an ipc identifier |
259 | * @ids: ipc identifier set | |
260 | * @new: new ipc permission set | |
261 | * @size: limit for the number of used ids | |
1da177e4 | 262 | * |
8001c858 DB |
263 | * Add an entry 'new' to the ipc ids idr. The permissions object is |
264 | * initialised and the first free entry is set up and the id assigned | |
265 | * is returned. The 'new' entry is returned in a locked state on success. | |
266 | * On failure the entry is not locked and a negative err-code is returned. | |
1da177e4 | 267 | * |
8001c858 | 268 | * Called with writer ipc_ids.rwsem held. |
1da177e4 | 269 | */ |
239521f3 | 270 | int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int size) |
1da177e4 | 271 | { |
1efdb69b EB |
272 | kuid_t euid; |
273 | kgid_t egid; | |
54924ea3 | 274 | int id; |
03f59566 | 275 | int next_id = ids->next_id; |
1da177e4 | 276 | |
7ca7e564 ND |
277 | if (size > IPCMNI) |
278 | size = IPCMNI; | |
279 | ||
280 | if (ids->in_use >= size) | |
283bb7fa | 281 | return -ENOSPC; |
7ca7e564 | 282 | |
54924ea3 TH |
283 | idr_preload(GFP_KERNEL); |
284 | ||
e00b4ff7 | 285 | spin_lock_init(&new->lock); |
72a8ff2f | 286 | new->deleted = false; |
e00b4ff7 ND |
287 | rcu_read_lock(); |
288 | spin_lock(&new->lock); | |
289 | ||
54924ea3 TH |
290 | id = idr_alloc(&ids->ipcs_idr, new, |
291 | (next_id < 0) ? 0 : ipcid_to_idx(next_id), 0, | |
292 | GFP_NOWAIT); | |
293 | idr_preload_end(); | |
294 | if (id < 0) { | |
e00b4ff7 ND |
295 | spin_unlock(&new->lock); |
296 | rcu_read_unlock(); | |
54924ea3 | 297 | return id; |
e00b4ff7 | 298 | } |
7ca7e564 | 299 | |
1da177e4 | 300 | ids->in_use++; |
1da177e4 | 301 | |
414c0708 DH |
302 | current_euid_egid(&euid, &egid); |
303 | new->cuid = new->uid = euid; | |
304 | new->gid = new->cgid = egid; | |
1da177e4 | 305 | |
03f59566 SK |
306 | if (next_id < 0) { |
307 | new->seq = ids->seq++; | |
308 | if (ids->seq > ids->seq_max) | |
309 | ids->seq = 0; | |
310 | } else { | |
311 | new->seq = ipcid_to_seqx(next_id); | |
312 | ids->next_id = -1; | |
313 | } | |
1da177e4 | 314 | |
48dea404 | 315 | new->id = ipc_buildid(id, new->seq); |
1da177e4 LT |
316 | return id; |
317 | } | |
318 | ||
7748dbfa | 319 | /** |
8001c858 DB |
320 | * ipcget_new - create a new ipc object |
321 | * @ns: ipc namespace | |
322 | * @ids: ipc identifer set | |
323 | * @ops: the actual creation routine to call | |
324 | * @params: its parameters | |
325 | * | |
326 | * This routine is called by sys_msgget, sys_semget() and sys_shmget() | |
327 | * when the key is IPC_PRIVATE. | |
7748dbfa | 328 | */ |
b2d75cdd | 329 | static int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids, |
7748dbfa ND |
330 | struct ipc_ops *ops, struct ipc_params *params) |
331 | { | |
332 | int err; | |
7748dbfa | 333 | |
d9a605e4 | 334 | down_write(&ids->rwsem); |
7748dbfa | 335 | err = ops->getnew(ns, params); |
d9a605e4 | 336 | up_write(&ids->rwsem); |
7748dbfa ND |
337 | return err; |
338 | } | |
339 | ||
340 | /** | |
8001c858 DB |
341 | * ipc_check_perms - check security and permissions for an ipc object |
342 | * @ns: ipc namespace | |
343 | * @ipcp: ipc permission set | |
344 | * @ops: the actual security routine to call | |
345 | * @params: its parameters | |
f4566f04 | 346 | * |
8001c858 DB |
347 | * This routine is called by sys_msgget(), sys_semget() and sys_shmget() |
348 | * when the key is not IPC_PRIVATE and that key already exists in the | |
349 | * ds IDR. | |
f4566f04 | 350 | * |
8001c858 | 351 | * On success, the ipc id is returned. |
f4566f04 | 352 | * |
8001c858 | 353 | * It is called with ipc_ids.rwsem and ipcp->lock held. |
7748dbfa | 354 | */ |
b0e77598 SH |
355 | static int ipc_check_perms(struct ipc_namespace *ns, |
356 | struct kern_ipc_perm *ipcp, | |
357 | struct ipc_ops *ops, | |
358 | struct ipc_params *params) | |
7748dbfa ND |
359 | { |
360 | int err; | |
361 | ||
b0e77598 | 362 | if (ipcperms(ns, ipcp, params->flg)) |
7748dbfa ND |
363 | err = -EACCES; |
364 | else { | |
365 | err = ops->associate(ipcp, params->flg); | |
366 | if (!err) | |
367 | err = ipcp->id; | |
368 | } | |
369 | ||
370 | return err; | |
371 | } | |
372 | ||
373 | /** | |
8001c858 DB |
374 | * ipcget_public - get an ipc object or create a new one |
375 | * @ns: ipc namespace | |
376 | * @ids: ipc identifer set | |
377 | * @ops: the actual creation routine to call | |
378 | * @params: its parameters | |
379 | * | |
380 | * This routine is called by sys_msgget, sys_semget() and sys_shmget() | |
381 | * when the key is not IPC_PRIVATE. | |
382 | * It adds a new entry if the key is not found and does some permission | |
383 | * / security checkings if the key is found. | |
384 | * | |
385 | * On success, the ipc id is returned. | |
7748dbfa | 386 | */ |
b2d75cdd | 387 | static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids, |
7748dbfa ND |
388 | struct ipc_ops *ops, struct ipc_params *params) |
389 | { | |
390 | struct kern_ipc_perm *ipcp; | |
391 | int flg = params->flg; | |
392 | int err; | |
7748dbfa | 393 | |
3e148c79 ND |
394 | /* |
395 | * Take the lock as a writer since we are potentially going to add | |
396 | * a new entry + read locks are not "upgradable" | |
397 | */ | |
d9a605e4 | 398 | down_write(&ids->rwsem); |
7748dbfa ND |
399 | ipcp = ipc_findkey(ids, params->key); |
400 | if (ipcp == NULL) { | |
401 | /* key not used */ | |
402 | if (!(flg & IPC_CREAT)) | |
403 | err = -ENOENT; | |
7748dbfa ND |
404 | else |
405 | err = ops->getnew(ns, params); | |
406 | } else { | |
407 | /* ipc object has been locked by ipc_findkey() */ | |
408 | ||
409 | if (flg & IPC_CREAT && flg & IPC_EXCL) | |
410 | err = -EEXIST; | |
411 | else { | |
412 | err = 0; | |
413 | if (ops->more_checks) | |
414 | err = ops->more_checks(ipcp, params); | |
415 | if (!err) | |
f4566f04 ND |
416 | /* |
417 | * ipc_check_perms returns the IPC id on | |
418 | * success | |
419 | */ | |
b0e77598 | 420 | err = ipc_check_perms(ns, ipcp, ops, params); |
7748dbfa ND |
421 | } |
422 | ipc_unlock(ipcp); | |
423 | } | |
d9a605e4 | 424 | up_write(&ids->rwsem); |
7748dbfa ND |
425 | |
426 | return err; | |
427 | } | |
428 | ||
429 | ||
1da177e4 | 430 | /** |
8001c858 DB |
431 | * ipc_rmid - remove an ipc identifier |
432 | * @ids: ipc identifier set | |
433 | * @ipcp: ipc perm structure containing the identifier to remove | |
1da177e4 | 434 | * |
8001c858 DB |
435 | * ipc_ids.rwsem (as a writer) and the spinlock for this ID are held |
436 | * before this function is called, and remain locked on the exit. | |
1da177e4 | 437 | */ |
7ca7e564 | 438 | void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp) |
1da177e4 | 439 | { |
ce621f5b | 440 | int lid = ipcid_to_idx(ipcp->id); |
7ca7e564 ND |
441 | |
442 | idr_remove(&ids->ipcs_idr, lid); | |
1da177e4 | 443 | |
1da177e4 LT |
444 | ids->in_use--; |
445 | ||
72a8ff2f | 446 | ipcp->deleted = true; |
7ca7e564 ND |
447 | |
448 | return; | |
1da177e4 LT |
449 | } |
450 | ||
451 | /** | |
8001c858 DB |
452 | * ipc_alloc - allocate ipc space |
453 | * @size: size desired | |
1da177e4 | 454 | * |
8001c858 DB |
455 | * Allocate memory from the appropriate pools and return a pointer to it. |
456 | * NULL is returned if the allocation fails | |
1da177e4 | 457 | */ |
6062a8dc | 458 | void *ipc_alloc(int size) |
1da177e4 | 459 | { |
6062a8dc | 460 | void *out; |
239521f3 | 461 | if (size > PAGE_SIZE) |
1da177e4 LT |
462 | out = vmalloc(size); |
463 | else | |
464 | out = kmalloc(size, GFP_KERNEL); | |
465 | return out; | |
466 | } | |
467 | ||
468 | /** | |
8001c858 DB |
469 | * ipc_free - free ipc space |
470 | * @ptr: pointer returned by ipc_alloc | |
471 | * @size: size of block | |
1da177e4 | 472 | * |
8001c858 DB |
473 | * Free a block created with ipc_alloc(). The caller must know the size |
474 | * used in the allocation call. | |
1da177e4 | 475 | */ |
239521f3 | 476 | void ipc_free(void *ptr, int size) |
1da177e4 | 477 | { |
239521f3 | 478 | if (size > PAGE_SIZE) |
1da177e4 LT |
479 | vfree(ptr); |
480 | else | |
481 | kfree(ptr); | |
482 | } | |
483 | ||
1da177e4 | 484 | /** |
8001c858 DB |
485 | * ipc_rcu_alloc - allocate ipc and rcu space |
486 | * @size: size desired | |
1da177e4 | 487 | * |
8001c858 DB |
488 | * Allocate memory for the rcu header structure + the object. |
489 | * Returns the pointer to the object or NULL upon failure. | |
1da177e4 | 490 | */ |
6062a8dc | 491 | void *ipc_rcu_alloc(int size) |
1da177e4 | 492 | { |
6062a8dc | 493 | /* |
600fe975 | 494 | * We prepend the allocation with the rcu struct |
1da177e4 | 495 | */ |
600fe975 AV |
496 | struct ipc_rcu *out = ipc_alloc(sizeof(struct ipc_rcu) + size); |
497 | if (unlikely(!out)) | |
498 | return NULL; | |
499 | atomic_set(&out->refcount, 1); | |
196aa013 | 500 | return out + 1; |
1da177e4 LT |
501 | } |
502 | ||
6062a8dc | 503 | int ipc_rcu_getref(void *ptr) |
1da177e4 | 504 | { |
196aa013 MS |
505 | struct ipc_rcu *p = ((struct ipc_rcu *)ptr) - 1; |
506 | ||
507 | return atomic_inc_not_zero(&p->refcount); | |
65f27f38 DH |
508 | } |
509 | ||
53dad6d3 | 510 | void ipc_rcu_putref(void *ptr, void (*func)(struct rcu_head *head)) |
1da177e4 | 511 | { |
196aa013 | 512 | struct ipc_rcu *p = ((struct ipc_rcu *)ptr) - 1; |
600fe975 AV |
513 | |
514 | if (!atomic_dec_and_test(&p->refcount)) | |
1da177e4 LT |
515 | return; |
516 | ||
53dad6d3 DB |
517 | call_rcu(&p->rcu, func); |
518 | } | |
519 | ||
520 | void ipc_rcu_free(struct rcu_head *head) | |
521 | { | |
522 | struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu); | |
523 | ||
524 | if (is_vmalloc_addr(p)) | |
525 | vfree(p); | |
526 | else | |
527 | kfree(p); | |
1da177e4 LT |
528 | } |
529 | ||
530 | /** | |
8001c858 DB |
531 | * ipcperms - check ipc permissions |
532 | * @ns: ipc namespace | |
533 | * @ipcp: ipc permission set | |
534 | * @flag: desired permission set | |
1da177e4 | 535 | * |
8001c858 DB |
536 | * Check user, group, other permissions for access |
537 | * to ipc resources. return 0 if allowed | |
b0e77598 | 538 | * |
8001c858 | 539 | * @flag will most probably be 0 or S_...UGO from <linux/stat.h> |
1da177e4 | 540 | */ |
b0e77598 SH |
541 | int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flag) |
542 | { | |
1efdb69b | 543 | kuid_t euid = current_euid(); |
a33e6751 | 544 | int requested_mode, granted_mode; |
1da177e4 | 545 | |
a33e6751 | 546 | audit_ipc_obj(ipcp); |
1da177e4 LT |
547 | requested_mode = (flag >> 6) | (flag >> 3) | flag; |
548 | granted_mode = ipcp->mode; | |
1efdb69b EB |
549 | if (uid_eq(euid, ipcp->cuid) || |
550 | uid_eq(euid, ipcp->uid)) | |
1da177e4 LT |
551 | granted_mode >>= 6; |
552 | else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid)) | |
553 | granted_mode >>= 3; | |
554 | /* is there some bit set in requested_mode but not in granted_mode? */ | |
555 | if ((requested_mode & ~granted_mode & 0007) && | |
b0e77598 | 556 | !ns_capable(ns->user_ns, CAP_IPC_OWNER)) |
1da177e4 LT |
557 | return -1; |
558 | ||
559 | return security_ipc_permission(ipcp, flag); | |
560 | } | |
561 | ||
562 | /* | |
563 | * Functions to convert between the kern_ipc_perm structure and the | |
564 | * old/new ipc_perm structures | |
565 | */ | |
566 | ||
567 | /** | |
8001c858 DB |
568 | * kernel_to_ipc64_perm - convert kernel ipc permissions to user |
569 | * @in: kernel permissions | |
570 | * @out: new style ipc permissions | |
1da177e4 | 571 | * |
8001c858 DB |
572 | * Turn the kernel object @in into a set of permissions descriptions |
573 | * for returning to userspace (@out). | |
1da177e4 | 574 | */ |
239521f3 | 575 | void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out) |
1da177e4 LT |
576 | { |
577 | out->key = in->key; | |
1efdb69b EB |
578 | out->uid = from_kuid_munged(current_user_ns(), in->uid); |
579 | out->gid = from_kgid_munged(current_user_ns(), in->gid); | |
580 | out->cuid = from_kuid_munged(current_user_ns(), in->cuid); | |
581 | out->cgid = from_kgid_munged(current_user_ns(), in->cgid); | |
1da177e4 LT |
582 | out->mode = in->mode; |
583 | out->seq = in->seq; | |
584 | } | |
585 | ||
586 | /** | |
8001c858 DB |
587 | * ipc64_perm_to_ipc_perm - convert new ipc permissions to old |
588 | * @in: new style ipc permissions | |
589 | * @out: old style ipc permissions | |
1da177e4 | 590 | * |
8001c858 DB |
591 | * Turn the new style permissions object @in into a compatibility |
592 | * object and store it into the @out pointer. | |
1da177e4 | 593 | */ |
239521f3 | 594 | void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out) |
1da177e4 LT |
595 | { |
596 | out->key = in->key; | |
597 | SET_UID(out->uid, in->uid); | |
598 | SET_GID(out->gid, in->gid); | |
599 | SET_UID(out->cuid, in->cuid); | |
600 | SET_GID(out->cgid, in->cgid); | |
601 | out->mode = in->mode; | |
602 | out->seq = in->seq; | |
603 | } | |
604 | ||
4d2bff5e DB |
605 | /** |
606 | * ipc_obtain_object | |
607 | * @ids: ipc identifier set | |
608 | * @id: ipc id to look for | |
609 | * | |
610 | * Look for an id in the ipc ids idr and return associated ipc object. | |
611 | * | |
612 | * Call inside the RCU critical section. | |
613 | * The ipc object is *not* locked on exit. | |
614 | */ | |
615 | struct kern_ipc_perm *ipc_obtain_object(struct ipc_ids *ids, int id) | |
616 | { | |
617 | struct kern_ipc_perm *out; | |
618 | int lid = ipcid_to_idx(id); | |
619 | ||
620 | out = idr_find(&ids->ipcs_idr, lid); | |
621 | if (!out) | |
622 | return ERR_PTR(-EINVAL); | |
623 | ||
624 | return out; | |
625 | } | |
626 | ||
f4566f04 | 627 | /** |
8001c858 DB |
628 | * ipc_lock - lock an ipc structure without rwsem held |
629 | * @ids: ipc identifier set | |
f4566f04 ND |
630 | * @id: ipc id to look for |
631 | * | |
632 | * Look for an id in the ipc ids idr and lock the associated ipc object. | |
633 | * | |
4d2bff5e | 634 | * The ipc object is locked on successful exit. |
f4566f04 | 635 | */ |
7ca7e564 | 636 | struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id) |
1da177e4 | 637 | { |
7ca7e564 | 638 | struct kern_ipc_perm *out; |
1da177e4 LT |
639 | |
640 | rcu_read_lock(); | |
4d2bff5e DB |
641 | out = ipc_obtain_object(ids, id); |
642 | if (IS_ERR(out)) | |
643 | goto err1; | |
7ca7e564 | 644 | |
1da177e4 | 645 | spin_lock(&out->lock); |
4d2bff5e | 646 | |
1da177e4 LT |
647 | /* ipc_rmid() may have already freed the ID while ipc_lock |
648 | * was spinning: here verify that the structure is still valid | |
649 | */ | |
72a8ff2f | 650 | if (ipc_valid_object(out)) |
4d2bff5e DB |
651 | return out; |
652 | ||
653 | spin_unlock(&out->lock); | |
654 | out = ERR_PTR(-EINVAL); | |
655 | err1: | |
656 | rcu_read_unlock(); | |
657 | return out; | |
658 | } | |
7ca7e564 | 659 | |
4d2bff5e DB |
660 | /** |
661 | * ipc_obtain_object_check | |
662 | * @ids: ipc identifier set | |
663 | * @id: ipc id to look for | |
664 | * | |
665 | * Similar to ipc_obtain_object() but also checks | |
666 | * the ipc object reference counter. | |
667 | * | |
668 | * Call inside the RCU critical section. | |
669 | * The ipc object is *not* locked on exit. | |
670 | */ | |
671 | struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id) | |
672 | { | |
673 | struct kern_ipc_perm *out = ipc_obtain_object(ids, id); | |
674 | ||
675 | if (IS_ERR(out)) | |
676 | goto out; | |
677 | ||
678 | if (ipc_checkid(out, id)) | |
679 | return ERR_PTR(-EIDRM); | |
680 | out: | |
1da177e4 LT |
681 | return out; |
682 | } | |
683 | ||
b2d75cdd PE |
684 | /** |
685 | * ipcget - Common sys_*get() code | |
8001c858 DB |
686 | * @ns: namsepace |
687 | * @ids: ipc identifier set | |
688 | * @ops: operations to be called on ipc object creation, permission checks | |
689 | * and further checks | |
690 | * @params: the parameters needed by the previous operations. | |
b2d75cdd PE |
691 | * |
692 | * Common routine called by sys_msgget(), sys_semget() and sys_shmget(). | |
693 | */ | |
694 | int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, | |
695 | struct ipc_ops *ops, struct ipc_params *params) | |
696 | { | |
697 | if (params->key == IPC_PRIVATE) | |
698 | return ipcget_new(ns, ids, ops, params); | |
699 | else | |
700 | return ipcget_public(ns, ids, ops, params); | |
701 | } | |
702 | ||
8f4a3809 | 703 | /** |
8001c858 | 704 | * ipc_update_perm - update the permissions of an ipc object |
8f4a3809 PP |
705 | * @in: the permission given as input. |
706 | * @out: the permission of the ipc to set. | |
707 | */ | |
1efdb69b | 708 | int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out) |
8f4a3809 | 709 | { |
1efdb69b EB |
710 | kuid_t uid = make_kuid(current_user_ns(), in->uid); |
711 | kgid_t gid = make_kgid(current_user_ns(), in->gid); | |
712 | if (!uid_valid(uid) || !gid_valid(gid)) | |
713 | return -EINVAL; | |
714 | ||
715 | out->uid = uid; | |
716 | out->gid = gid; | |
8f4a3809 PP |
717 | out->mode = (out->mode & ~S_IRWXUGO) |
718 | | (in->mode & S_IRWXUGO); | |
1efdb69b EB |
719 | |
720 | return 0; | |
8f4a3809 PP |
721 | } |
722 | ||
a5f75e7f | 723 | /** |
3b1c4ad3 | 724 | * ipcctl_pre_down_nolock - retrieve an ipc and check permissions for some IPC_XXX cmd |
8001c858 | 725 | * @ns: ipc namespace |
a5f75e7f PP |
726 | * @ids: the table of ids where to look for the ipc |
727 | * @id: the id of the ipc to retrieve | |
728 | * @cmd: the cmd to check | |
729 | * @perm: the permission to set | |
730 | * @extra_perm: one extra permission parameter used by msq | |
731 | * | |
732 | * This function does some common audit and permissions check for some IPC_XXX | |
733 | * cmd and is called from semctl_down, shmctl_down and msgctl_down. | |
734 | * It must be called without any lock held and | |
735 | * - retrieves the ipc with the given id in the given table. | |
736 | * - performs some audit and permission check, depending on the given cmd | |
3b1c4ad3 | 737 | * - returns a pointer to the ipc object or otherwise, the corresponding error. |
7b4cc5d8 | 738 | * |
d9a605e4 | 739 | * Call holding the both the rwsem and the rcu read lock. |
a5f75e7f | 740 | */ |
444d0f62 | 741 | struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns, |
3b1c4ad3 DB |
742 | struct ipc_ids *ids, int id, int cmd, |
743 | struct ipc64_perm *perm, int extra_perm) | |
444d0f62 | 744 | { |
1efdb69b | 745 | kuid_t euid; |
444d0f62 DB |
746 | int err = -EPERM; |
747 | struct kern_ipc_perm *ipcp; | |
a5f75e7f | 748 | |
444d0f62 | 749 | ipcp = ipc_obtain_object_check(ids, id); |
a5f75e7f PP |
750 | if (IS_ERR(ipcp)) { |
751 | err = PTR_ERR(ipcp); | |
7b4cc5d8 | 752 | goto err; |
a5f75e7f PP |
753 | } |
754 | ||
a33e6751 | 755 | audit_ipc_obj(ipcp); |
e816f370 AV |
756 | if (cmd == IPC_SET) |
757 | audit_ipc_set_perm(extra_perm, perm->uid, | |
444d0f62 | 758 | perm->gid, perm->mode); |
414c0708 DH |
759 | |
760 | euid = current_euid(); | |
1efdb69b | 761 | if (uid_eq(euid, ipcp->cuid) || uid_eq(euid, ipcp->uid) || |
b0e77598 | 762 | ns_capable(ns->user_ns, CAP_SYS_ADMIN)) |
7b4cc5d8 DB |
763 | return ipcp; /* successful lookup */ |
764 | err: | |
a5f75e7f PP |
765 | return ERR_PTR(err); |
766 | } | |
767 | ||
c1d7e01d | 768 | #ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION |
1da177e4 LT |
769 | |
770 | ||
771 | /** | |
8001c858 DB |
772 | * ipc_parse_version - ipc call version |
773 | * @cmd: pointer to command | |
1da177e4 | 774 | * |
8001c858 DB |
775 | * Return IPC_64 for new style IPC and IPC_OLD for old style IPC. |
776 | * The @cmd value is turned from an encoding command and version into | |
777 | * just the command code. | |
1da177e4 | 778 | */ |
239521f3 | 779 | int ipc_parse_version(int *cmd) |
1da177e4 LT |
780 | { |
781 | if (*cmd & IPC_64) { | |
782 | *cmd ^= IPC_64; | |
783 | return IPC_64; | |
784 | } else { | |
785 | return IPC_OLD; | |
786 | } | |
787 | } | |
788 | ||
c1d7e01d | 789 | #endif /* CONFIG_ARCH_WANT_IPC_PARSE_VERSION */ |
ae781774 MW |
790 | |
791 | #ifdef CONFIG_PROC_FS | |
bc1fc6d8 EB |
792 | struct ipc_proc_iter { |
793 | struct ipc_namespace *ns; | |
794 | struct ipc_proc_iface *iface; | |
795 | }; | |
796 | ||
7ca7e564 ND |
797 | /* |
798 | * This routine locks the ipc structure found at least at position pos. | |
799 | */ | |
b524b9ad AB |
800 | static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos, |
801 | loff_t *new_pos) | |
ae781774 | 802 | { |
7ca7e564 ND |
803 | struct kern_ipc_perm *ipc; |
804 | int total, id; | |
73ea4130 | 805 | |
7ca7e564 ND |
806 | total = 0; |
807 | for (id = 0; id < pos && total < ids->in_use; id++) { | |
808 | ipc = idr_find(&ids->ipcs_idr, id); | |
809 | if (ipc != NULL) | |
810 | total++; | |
811 | } | |
ae781774 | 812 | |
7ca7e564 ND |
813 | if (total >= ids->in_use) |
814 | return NULL; | |
ae781774 | 815 | |
239521f3 | 816 | for (; pos < IPCMNI; pos++) { |
7ca7e564 ND |
817 | ipc = idr_find(&ids->ipcs_idr, pos); |
818 | if (ipc != NULL) { | |
819 | *new_pos = pos + 1; | |
32a27500 DB |
820 | rcu_read_lock(); |
821 | ipc_lock_object(ipc); | |
ae781774 MW |
822 | return ipc; |
823 | } | |
824 | } | |
825 | ||
826 | /* Out of range - return NULL to terminate iteration */ | |
827 | return NULL; | |
828 | } | |
829 | ||
7ca7e564 ND |
830 | static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos) |
831 | { | |
832 | struct ipc_proc_iter *iter = s->private; | |
833 | struct ipc_proc_iface *iface = iter->iface; | |
834 | struct kern_ipc_perm *ipc = it; | |
835 | ||
836 | /* If we had an ipc id locked before, unlock it */ | |
837 | if (ipc && ipc != SEQ_START_TOKEN) | |
838 | ipc_unlock(ipc); | |
839 | ||
ed2ddbf8 | 840 | return sysvipc_find_ipc(&iter->ns->ids[iface->ids], *pos, pos); |
7ca7e564 ND |
841 | } |
842 | ||
ae781774 | 843 | /* |
f4566f04 ND |
844 | * File positions: pos 0 -> header, pos n -> ipc id = n - 1. |
845 | * SeqFile iterator: iterator value locked ipc pointer or SEQ_TOKEN_START. | |
ae781774 MW |
846 | */ |
847 | static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos) | |
848 | { | |
bc1fc6d8 EB |
849 | struct ipc_proc_iter *iter = s->private; |
850 | struct ipc_proc_iface *iface = iter->iface; | |
73ea4130 KK |
851 | struct ipc_ids *ids; |
852 | ||
ed2ddbf8 | 853 | ids = &iter->ns->ids[iface->ids]; |
ae781774 MW |
854 | |
855 | /* | |
856 | * Take the lock - this will be released by the corresponding | |
857 | * call to stop(). | |
858 | */ | |
d9a605e4 | 859 | down_read(&ids->rwsem); |
ae781774 MW |
860 | |
861 | /* pos < 0 is invalid */ | |
862 | if (*pos < 0) | |
863 | return NULL; | |
864 | ||
865 | /* pos == 0 means header */ | |
866 | if (*pos == 0) | |
867 | return SEQ_START_TOKEN; | |
868 | ||
869 | /* Find the (pos-1)th ipc */ | |
7ca7e564 | 870 | return sysvipc_find_ipc(ids, *pos - 1, pos); |
ae781774 MW |
871 | } |
872 | ||
873 | static void sysvipc_proc_stop(struct seq_file *s, void *it) | |
874 | { | |
875 | struct kern_ipc_perm *ipc = it; | |
bc1fc6d8 EB |
876 | struct ipc_proc_iter *iter = s->private; |
877 | struct ipc_proc_iface *iface = iter->iface; | |
73ea4130 | 878 | struct ipc_ids *ids; |
ae781774 | 879 | |
f4566f04 | 880 | /* If we had a locked structure, release it */ |
ae781774 MW |
881 | if (ipc && ipc != SEQ_START_TOKEN) |
882 | ipc_unlock(ipc); | |
883 | ||
ed2ddbf8 | 884 | ids = &iter->ns->ids[iface->ids]; |
ae781774 | 885 | /* Release the lock we took in start() */ |
d9a605e4 | 886 | up_read(&ids->rwsem); |
ae781774 MW |
887 | } |
888 | ||
889 | static int sysvipc_proc_show(struct seq_file *s, void *it) | |
890 | { | |
bc1fc6d8 EB |
891 | struct ipc_proc_iter *iter = s->private; |
892 | struct ipc_proc_iface *iface = iter->iface; | |
ae781774 MW |
893 | |
894 | if (it == SEQ_START_TOKEN) | |
895 | return seq_puts(s, iface->header); | |
896 | ||
897 | return iface->show(s, it); | |
898 | } | |
899 | ||
88e9d34c | 900 | static const struct seq_operations sysvipc_proc_seqops = { |
ae781774 MW |
901 | .start = sysvipc_proc_start, |
902 | .stop = sysvipc_proc_stop, | |
903 | .next = sysvipc_proc_next, | |
904 | .show = sysvipc_proc_show, | |
905 | }; | |
906 | ||
bc1fc6d8 EB |
907 | static int sysvipc_proc_open(struct inode *inode, struct file *file) |
908 | { | |
ae781774 MW |
909 | int ret; |
910 | struct seq_file *seq; | |
bc1fc6d8 EB |
911 | struct ipc_proc_iter *iter; |
912 | ||
913 | ret = -ENOMEM; | |
914 | iter = kmalloc(sizeof(*iter), GFP_KERNEL); | |
915 | if (!iter) | |
916 | goto out; | |
ae781774 MW |
917 | |
918 | ret = seq_open(file, &sysvipc_proc_seqops); | |
bc1fc6d8 EB |
919 | if (ret) |
920 | goto out_kfree; | |
921 | ||
922 | seq = file->private_data; | |
923 | seq->private = iter; | |
924 | ||
d9dda78b | 925 | iter->iface = PDE_DATA(inode); |
bc1fc6d8 EB |
926 | iter->ns = get_ipc_ns(current->nsproxy->ipc_ns); |
927 | out: | |
ae781774 | 928 | return ret; |
bc1fc6d8 EB |
929 | out_kfree: |
930 | kfree(iter); | |
931 | goto out; | |
932 | } | |
933 | ||
934 | static int sysvipc_proc_release(struct inode *inode, struct file *file) | |
935 | { | |
936 | struct seq_file *seq = file->private_data; | |
937 | struct ipc_proc_iter *iter = seq->private; | |
938 | put_ipc_ns(iter->ns); | |
939 | return seq_release_private(inode, file); | |
ae781774 MW |
940 | } |
941 | ||
9a32144e | 942 | static const struct file_operations sysvipc_proc_fops = { |
ae781774 MW |
943 | .open = sysvipc_proc_open, |
944 | .read = seq_read, | |
945 | .llseek = seq_lseek, | |
bc1fc6d8 | 946 | .release = sysvipc_proc_release, |
ae781774 MW |
947 | }; |
948 | #endif /* CONFIG_PROC_FS */ |