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 LT |
112 | /** |
113 | * ipc_init - initialise IPC subsystem | |
114 | * | |
115 | * The various system5 IPC resources (semaphores, messages and shared | |
72fd4a35 | 116 | * memory) are initialised |
b6b337ad ND |
117 | * A callback routine is registered into the memory hotplug notifier |
118 | * chain: since msgmni scales to lowmem this callback routine will be | |
119 | * called upon successful memory add / remove to recompute msmgni. | |
1da177e4 LT |
120 | */ |
121 | ||
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 | /** | |
134 | * ipc_init_ids - initialise IPC identifiers | |
135 | * @ids: Identifier set | |
1da177e4 | 136 | * |
7ca7e564 ND |
137 | * Set up the sequence range to use for the ipc identifier range (limited |
138 | * below IPCMNI) then initialise the ids idr. | |
1da177e4 LT |
139 | */ |
140 | ||
7ca7e564 | 141 | void ipc_init_ids(struct ipc_ids *ids) |
1da177e4 | 142 | { |
d9a605e4 | 143 | init_rwsem(&ids->rwsem); |
1da177e4 | 144 | |
1da177e4 | 145 | ids->in_use = 0; |
1da177e4 | 146 | ids->seq = 0; |
03f59566 | 147 | ids->next_id = -1; |
1da177e4 LT |
148 | { |
149 | int seq_limit = INT_MAX/SEQ_MULTIPLIER; | |
4be929be AD |
150 | if (seq_limit > USHRT_MAX) |
151 | ids->seq_max = USHRT_MAX; | |
1da177e4 LT |
152 | else |
153 | ids->seq_max = seq_limit; | |
154 | } | |
155 | ||
7ca7e564 | 156 | idr_init(&ids->ipcs_idr); |
1da177e4 LT |
157 | } |
158 | ||
ae781774 | 159 | #ifdef CONFIG_PROC_FS |
9a32144e | 160 | static const struct file_operations sysvipc_proc_fops; |
ae781774 | 161 | /** |
72fd4a35 | 162 | * ipc_init_proc_interface - Create a proc interface for sysipc types using a seq_file interface. |
ae781774 MW |
163 | * @path: Path in procfs |
164 | * @header: Banner to be printed at the beginning of the file. | |
165 | * @ids: ipc id table to iterate. | |
166 | * @show: show routine. | |
167 | */ | |
168 | void __init ipc_init_proc_interface(const char *path, const char *header, | |
73ea4130 | 169 | int ids, int (*show)(struct seq_file *, void *)) |
ae781774 MW |
170 | { |
171 | struct proc_dir_entry *pde; | |
172 | struct ipc_proc_iface *iface; | |
173 | ||
174 | iface = kmalloc(sizeof(*iface), GFP_KERNEL); | |
175 | if (!iface) | |
176 | return; | |
177 | iface->path = path; | |
178 | iface->header = header; | |
179 | iface->ids = ids; | |
180 | iface->show = show; | |
181 | ||
6a6375db DL |
182 | pde = proc_create_data(path, |
183 | S_IRUGO, /* world readable */ | |
184 | NULL, /* parent dir */ | |
185 | &sysvipc_proc_fops, | |
186 | iface); | |
187 | if (!pde) { | |
ae781774 MW |
188 | kfree(iface); |
189 | } | |
190 | } | |
191 | #endif | |
192 | ||
1da177e4 LT |
193 | /** |
194 | * ipc_findkey - find a key in an ipc identifier set | |
195 | * @ids: Identifier set | |
196 | * @key: The key to find | |
197 | * | |
d9a605e4 | 198 | * Requires ipc_ids.rwsem locked. |
7ca7e564 ND |
199 | * Returns the LOCKED pointer to the ipc structure if found or NULL |
200 | * if not. | |
f4566f04 | 201 | * If key is found ipc points to the owning ipc structure |
1da177e4 LT |
202 | */ |
203 | ||
7748dbfa | 204 | static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key) |
1da177e4 | 205 | { |
7ca7e564 ND |
206 | struct kern_ipc_perm *ipc; |
207 | int next_id; | |
208 | int total; | |
1da177e4 | 209 | |
7ca7e564 ND |
210 | for (total = 0, next_id = 0; total < ids->in_use; next_id++) { |
211 | ipc = idr_find(&ids->ipcs_idr, next_id); | |
212 | ||
213 | if (ipc == NULL) | |
1da177e4 | 214 | continue; |
7ca7e564 ND |
215 | |
216 | if (ipc->key != key) { | |
217 | total++; | |
218 | continue; | |
219 | } | |
220 | ||
32a27500 DB |
221 | rcu_read_lock(); |
222 | ipc_lock_object(ipc); | |
7ca7e564 | 223 | return ipc; |
1da177e4 | 224 | } |
7ca7e564 ND |
225 | |
226 | return NULL; | |
1da177e4 LT |
227 | } |
228 | ||
7ca7e564 ND |
229 | /** |
230 | * ipc_get_maxid - get the last assigned id | |
231 | * @ids: IPC identifier set | |
232 | * | |
d9a605e4 | 233 | * Called with ipc_ids.rwsem held. |
1da177e4 | 234 | */ |
1da177e4 | 235 | |
7ca7e564 ND |
236 | int ipc_get_maxid(struct ipc_ids *ids) |
237 | { | |
238 | struct kern_ipc_perm *ipc; | |
239 | int max_id = -1; | |
240 | int total, id; | |
241 | ||
242 | if (ids->in_use == 0) | |
243 | return -1; | |
1da177e4 | 244 | |
7ca7e564 ND |
245 | if (ids->in_use == IPCMNI) |
246 | return IPCMNI - 1; | |
247 | ||
248 | /* Look for the last assigned id */ | |
249 | total = 0; | |
250 | for (id = 0; id < IPCMNI && total < ids->in_use; id++) { | |
251 | ipc = idr_find(&ids->ipcs_idr, id); | |
252 | if (ipc != NULL) { | |
253 | max_id = id; | |
254 | total++; | |
255 | } | |
256 | } | |
257 | return max_id; | |
1da177e4 LT |
258 | } |
259 | ||
260 | /** | |
261 | * ipc_addid - add an IPC identifier | |
262 | * @ids: IPC identifier set | |
263 | * @new: new IPC permission set | |
7ca7e564 | 264 | * @size: limit for the number of used ids |
1da177e4 | 265 | * |
f4566f04 | 266 | * Add an entry 'new' to the IPC ids idr. The permissions object is |
1da177e4 | 267 | * initialised and the first free entry is set up and the id assigned |
f4566f04 | 268 | * is returned. The 'new' entry is returned in a locked state on success. |
283bb7fa | 269 | * On failure the entry is not locked and a negative err-code is returned. |
1da177e4 | 270 | * |
d9a605e4 | 271 | * Called with writer ipc_ids.rwsem held. |
1da177e4 | 272 | */ |
1da177e4 LT |
273 | int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size) |
274 | { | |
1efdb69b EB |
275 | kuid_t euid; |
276 | kgid_t egid; | |
54924ea3 | 277 | int id; |
03f59566 | 278 | int next_id = ids->next_id; |
1da177e4 | 279 | |
7ca7e564 ND |
280 | if (size > IPCMNI) |
281 | size = IPCMNI; | |
282 | ||
283 | if (ids->in_use >= size) | |
283bb7fa | 284 | return -ENOSPC; |
7ca7e564 | 285 | |
54924ea3 TH |
286 | idr_preload(GFP_KERNEL); |
287 | ||
e00b4ff7 ND |
288 | spin_lock_init(&new->lock); |
289 | new->deleted = 0; | |
290 | rcu_read_lock(); | |
291 | spin_lock(&new->lock); | |
292 | ||
54924ea3 TH |
293 | id = idr_alloc(&ids->ipcs_idr, new, |
294 | (next_id < 0) ? 0 : ipcid_to_idx(next_id), 0, | |
295 | GFP_NOWAIT); | |
296 | idr_preload_end(); | |
297 | if (id < 0) { | |
e00b4ff7 ND |
298 | spin_unlock(&new->lock); |
299 | rcu_read_unlock(); | |
54924ea3 | 300 | return id; |
e00b4ff7 | 301 | } |
7ca7e564 | 302 | |
1da177e4 | 303 | ids->in_use++; |
1da177e4 | 304 | |
414c0708 DH |
305 | current_euid_egid(&euid, &egid); |
306 | new->cuid = new->uid = euid; | |
307 | new->gid = new->cgid = egid; | |
1da177e4 | 308 | |
03f59566 SK |
309 | if (next_id < 0) { |
310 | new->seq = ids->seq++; | |
311 | if (ids->seq > ids->seq_max) | |
312 | ids->seq = 0; | |
313 | } else { | |
314 | new->seq = ipcid_to_seqx(next_id); | |
315 | ids->next_id = -1; | |
316 | } | |
1da177e4 | 317 | |
48dea404 | 318 | new->id = ipc_buildid(id, new->seq); |
1da177e4 LT |
319 | return id; |
320 | } | |
321 | ||
7748dbfa ND |
322 | /** |
323 | * ipcget_new - create a new ipc object | |
324 | * @ns: namespace | |
f4566f04 | 325 | * @ids: IPC identifer set |
7748dbfa ND |
326 | * @ops: the actual creation routine to call |
327 | * @params: its parameters | |
328 | * | |
f4566f04 ND |
329 | * This routine is called by sys_msgget, sys_semget() and sys_shmget() |
330 | * when the key is IPC_PRIVATE. | |
7748dbfa | 331 | */ |
b2d75cdd | 332 | static int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids, |
7748dbfa ND |
333 | struct ipc_ops *ops, struct ipc_params *params) |
334 | { | |
335 | int err; | |
7748dbfa | 336 | |
d9a605e4 | 337 | down_write(&ids->rwsem); |
7748dbfa | 338 | err = ops->getnew(ns, params); |
d9a605e4 | 339 | up_write(&ids->rwsem); |
7748dbfa ND |
340 | return err; |
341 | } | |
342 | ||
343 | /** | |
344 | * ipc_check_perms - check security and permissions for an IPC | |
6213cfe8 | 345 | * @ns: IPC namespace |
7748dbfa | 346 | * @ipcp: ipc permission set |
7748dbfa ND |
347 | * @ops: the actual security routine to call |
348 | * @params: its parameters | |
f4566f04 ND |
349 | * |
350 | * This routine is called by sys_msgget(), sys_semget() and sys_shmget() | |
351 | * when the key is not IPC_PRIVATE and that key already exists in the | |
352 | * ids IDR. | |
353 | * | |
354 | * On success, the IPC id is returned. | |
355 | * | |
d9a605e4 | 356 | * It is called with ipc_ids.rwsem and ipcp->lock held. |
7748dbfa | 357 | */ |
b0e77598 SH |
358 | static int ipc_check_perms(struct ipc_namespace *ns, |
359 | struct kern_ipc_perm *ipcp, | |
360 | struct ipc_ops *ops, | |
361 | struct ipc_params *params) | |
7748dbfa ND |
362 | { |
363 | int err; | |
364 | ||
b0e77598 | 365 | if (ipcperms(ns, ipcp, params->flg)) |
7748dbfa ND |
366 | err = -EACCES; |
367 | else { | |
368 | err = ops->associate(ipcp, params->flg); | |
369 | if (!err) | |
370 | err = ipcp->id; | |
371 | } | |
372 | ||
373 | return err; | |
374 | } | |
375 | ||
376 | /** | |
377 | * ipcget_public - get an ipc object or create a new one | |
378 | * @ns: namespace | |
f4566f04 | 379 | * @ids: IPC identifer set |
7748dbfa ND |
380 | * @ops: the actual creation routine to call |
381 | * @params: its parameters | |
382 | * | |
f4566f04 ND |
383 | * This routine is called by sys_msgget, sys_semget() and sys_shmget() |
384 | * when the key is not IPC_PRIVATE. | |
385 | * It adds a new entry if the key is not found and does some permission | |
386 | * / security checkings if the key is found. | |
387 | * | |
388 | * On success, the ipc id is returned. | |
7748dbfa | 389 | */ |
b2d75cdd | 390 | static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids, |
7748dbfa ND |
391 | struct ipc_ops *ops, struct ipc_params *params) |
392 | { | |
393 | struct kern_ipc_perm *ipcp; | |
394 | int flg = params->flg; | |
395 | int err; | |
7748dbfa | 396 | |
3e148c79 ND |
397 | /* |
398 | * Take the lock as a writer since we are potentially going to add | |
399 | * a new entry + read locks are not "upgradable" | |
400 | */ | |
d9a605e4 | 401 | down_write(&ids->rwsem); |
7748dbfa ND |
402 | ipcp = ipc_findkey(ids, params->key); |
403 | if (ipcp == NULL) { | |
404 | /* key not used */ | |
405 | if (!(flg & IPC_CREAT)) | |
406 | err = -ENOENT; | |
7748dbfa ND |
407 | else |
408 | err = ops->getnew(ns, params); | |
409 | } else { | |
410 | /* ipc object has been locked by ipc_findkey() */ | |
411 | ||
412 | if (flg & IPC_CREAT && flg & IPC_EXCL) | |
413 | err = -EEXIST; | |
414 | else { | |
415 | err = 0; | |
416 | if (ops->more_checks) | |
417 | err = ops->more_checks(ipcp, params); | |
418 | if (!err) | |
f4566f04 ND |
419 | /* |
420 | * ipc_check_perms returns the IPC id on | |
421 | * success | |
422 | */ | |
b0e77598 | 423 | err = ipc_check_perms(ns, ipcp, ops, params); |
7748dbfa ND |
424 | } |
425 | ipc_unlock(ipcp); | |
426 | } | |
d9a605e4 | 427 | up_write(&ids->rwsem); |
7748dbfa ND |
428 | |
429 | return err; | |
430 | } | |
431 | ||
432 | ||
1da177e4 LT |
433 | /** |
434 | * ipc_rmid - remove an IPC identifier | |
f4566f04 ND |
435 | * @ids: IPC identifier set |
436 | * @ipcp: ipc perm structure containing the identifier to remove | |
1da177e4 | 437 | * |
d9a605e4 | 438 | * ipc_ids.rwsem (as a writer) and the spinlock for this ID are held |
3e148c79 | 439 | * before this function is called, and remain locked on the exit. |
1da177e4 LT |
440 | */ |
441 | ||
7ca7e564 | 442 | void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp) |
1da177e4 | 443 | { |
ce621f5b | 444 | int lid = ipcid_to_idx(ipcp->id); |
7ca7e564 ND |
445 | |
446 | idr_remove(&ids->ipcs_idr, lid); | |
1da177e4 | 447 | |
1da177e4 LT |
448 | ids->in_use--; |
449 | ||
7ca7e564 ND |
450 | ipcp->deleted = 1; |
451 | ||
452 | return; | |
1da177e4 LT |
453 | } |
454 | ||
455 | /** | |
456 | * ipc_alloc - allocate ipc space | |
457 | * @size: size desired | |
458 | * | |
459 | * Allocate memory from the appropriate pools and return a pointer to it. | |
460 | * NULL is returned if the allocation fails | |
461 | */ | |
462 | ||
6062a8dc | 463 | void *ipc_alloc(int size) |
1da177e4 | 464 | { |
6062a8dc | 465 | void *out; |
1da177e4 LT |
466 | if(size > PAGE_SIZE) |
467 | out = vmalloc(size); | |
468 | else | |
469 | out = kmalloc(size, GFP_KERNEL); | |
470 | return out; | |
471 | } | |
472 | ||
473 | /** | |
474 | * ipc_free - free ipc space | |
475 | * @ptr: pointer returned by ipc_alloc | |
476 | * @size: size of block | |
477 | * | |
72fd4a35 | 478 | * Free a block created with ipc_alloc(). The caller must know the size |
1da177e4 LT |
479 | * used in the allocation call. |
480 | */ | |
481 | ||
482 | void ipc_free(void* ptr, int size) | |
483 | { | |
484 | if(size > PAGE_SIZE) | |
485 | vfree(ptr); | |
486 | else | |
487 | kfree(ptr); | |
488 | } | |
489 | ||
1da177e4 LT |
490 | /** |
491 | * ipc_rcu_alloc - allocate ipc and rcu space | |
492 | * @size: size desired | |
493 | * | |
494 | * Allocate memory for the rcu header structure + the object. | |
6062a8dc | 495 | * Returns the pointer to the object or NULL upon failure. |
1da177e4 | 496 | */ |
6062a8dc | 497 | void *ipc_rcu_alloc(int size) |
1da177e4 | 498 | { |
6062a8dc | 499 | /* |
600fe975 | 500 | * We prepend the allocation with the rcu struct |
1da177e4 | 501 | */ |
600fe975 AV |
502 | struct ipc_rcu *out = ipc_alloc(sizeof(struct ipc_rcu) + size); |
503 | if (unlikely(!out)) | |
504 | return NULL; | |
505 | atomic_set(&out->refcount, 1); | |
196aa013 | 506 | return out + 1; |
1da177e4 LT |
507 | } |
508 | ||
6062a8dc | 509 | int ipc_rcu_getref(void *ptr) |
1da177e4 | 510 | { |
196aa013 MS |
511 | struct ipc_rcu *p = ((struct ipc_rcu *)ptr) - 1; |
512 | ||
513 | return atomic_inc_not_zero(&p->refcount); | |
65f27f38 DH |
514 | } |
515 | ||
53dad6d3 | 516 | void ipc_rcu_putref(void *ptr, void (*func)(struct rcu_head *head)) |
1da177e4 | 517 | { |
196aa013 | 518 | struct ipc_rcu *p = ((struct ipc_rcu *)ptr) - 1; |
600fe975 AV |
519 | |
520 | if (!atomic_dec_and_test(&p->refcount)) | |
1da177e4 LT |
521 | return; |
522 | ||
53dad6d3 DB |
523 | call_rcu(&p->rcu, func); |
524 | } | |
525 | ||
526 | void ipc_rcu_free(struct rcu_head *head) | |
527 | { | |
528 | struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu); | |
529 | ||
530 | if (is_vmalloc_addr(p)) | |
531 | vfree(p); | |
532 | else | |
533 | kfree(p); | |
1da177e4 LT |
534 | } |
535 | ||
536 | /** | |
537 | * ipcperms - check IPC permissions | |
6213cfe8 | 538 | * @ns: IPC namespace |
1da177e4 LT |
539 | * @ipcp: IPC permission set |
540 | * @flag: desired permission set. | |
541 | * | |
542 | * Check user, group, other permissions for access | |
543 | * to ipc resources. return 0 if allowed | |
b0e77598 SH |
544 | * |
545 | * @flag will most probably be 0 or S_...UGO from <linux/stat.h> | |
1da177e4 LT |
546 | */ |
547 | ||
b0e77598 SH |
548 | int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flag) |
549 | { | |
1efdb69b | 550 | kuid_t euid = current_euid(); |
a33e6751 | 551 | int requested_mode, granted_mode; |
1da177e4 | 552 | |
a33e6751 | 553 | audit_ipc_obj(ipcp); |
1da177e4 LT |
554 | requested_mode = (flag >> 6) | (flag >> 3) | flag; |
555 | granted_mode = ipcp->mode; | |
1efdb69b EB |
556 | if (uid_eq(euid, ipcp->cuid) || |
557 | uid_eq(euid, ipcp->uid)) | |
1da177e4 LT |
558 | granted_mode >>= 6; |
559 | else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid)) | |
560 | granted_mode >>= 3; | |
561 | /* is there some bit set in requested_mode but not in granted_mode? */ | |
562 | if ((requested_mode & ~granted_mode & 0007) && | |
b0e77598 | 563 | !ns_capable(ns->user_ns, CAP_IPC_OWNER)) |
1da177e4 LT |
564 | return -1; |
565 | ||
566 | return security_ipc_permission(ipcp, flag); | |
567 | } | |
568 | ||
569 | /* | |
570 | * Functions to convert between the kern_ipc_perm structure and the | |
571 | * old/new ipc_perm structures | |
572 | */ | |
573 | ||
574 | /** | |
575 | * kernel_to_ipc64_perm - convert kernel ipc permissions to user | |
576 | * @in: kernel permissions | |
577 | * @out: new style IPC permissions | |
578 | * | |
72fd4a35 RD |
579 | * Turn the kernel object @in into a set of permissions descriptions |
580 | * for returning to userspace (@out). | |
1da177e4 LT |
581 | */ |
582 | ||
583 | ||
584 | void kernel_to_ipc64_perm (struct kern_ipc_perm *in, struct ipc64_perm *out) | |
585 | { | |
586 | out->key = in->key; | |
1efdb69b EB |
587 | out->uid = from_kuid_munged(current_user_ns(), in->uid); |
588 | out->gid = from_kgid_munged(current_user_ns(), in->gid); | |
589 | out->cuid = from_kuid_munged(current_user_ns(), in->cuid); | |
590 | out->cgid = from_kgid_munged(current_user_ns(), in->cgid); | |
1da177e4 LT |
591 | out->mode = in->mode; |
592 | out->seq = in->seq; | |
593 | } | |
594 | ||
595 | /** | |
f4566f04 | 596 | * ipc64_perm_to_ipc_perm - convert new ipc permissions to old |
1da177e4 LT |
597 | * @in: new style IPC permissions |
598 | * @out: old style IPC permissions | |
599 | * | |
72fd4a35 RD |
600 | * Turn the new style permissions object @in into a compatibility |
601 | * object and store it into the @out pointer. | |
1da177e4 LT |
602 | */ |
603 | ||
604 | void ipc64_perm_to_ipc_perm (struct ipc64_perm *in, struct ipc_perm *out) | |
605 | { | |
606 | out->key = in->key; | |
607 | SET_UID(out->uid, in->uid); | |
608 | SET_GID(out->gid, in->gid); | |
609 | SET_UID(out->cuid, in->cuid); | |
610 | SET_GID(out->cgid, in->cgid); | |
611 | out->mode = in->mode; | |
612 | out->seq = in->seq; | |
613 | } | |
614 | ||
4d2bff5e DB |
615 | /** |
616 | * ipc_obtain_object | |
617 | * @ids: ipc identifier set | |
618 | * @id: ipc id to look for | |
619 | * | |
620 | * Look for an id in the ipc ids idr and return associated ipc object. | |
621 | * | |
622 | * Call inside the RCU critical section. | |
623 | * The ipc object is *not* locked on exit. | |
624 | */ | |
625 | struct kern_ipc_perm *ipc_obtain_object(struct ipc_ids *ids, int id) | |
626 | { | |
627 | struct kern_ipc_perm *out; | |
628 | int lid = ipcid_to_idx(id); | |
629 | ||
630 | out = idr_find(&ids->ipcs_idr, lid); | |
631 | if (!out) | |
632 | return ERR_PTR(-EINVAL); | |
633 | ||
634 | return out; | |
635 | } | |
636 | ||
f4566f04 | 637 | /** |
d9a605e4 | 638 | * ipc_lock - Lock an ipc structure without rwsem held |
f4566f04 ND |
639 | * @ids: IPC identifier set |
640 | * @id: ipc id to look for | |
641 | * | |
642 | * Look for an id in the ipc ids idr and lock the associated ipc object. | |
643 | * | |
4d2bff5e | 644 | * The ipc object is locked on successful exit. |
f4566f04 | 645 | */ |
7ca7e564 | 646 | struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id) |
1da177e4 | 647 | { |
7ca7e564 | 648 | struct kern_ipc_perm *out; |
1da177e4 LT |
649 | |
650 | rcu_read_lock(); | |
4d2bff5e DB |
651 | out = ipc_obtain_object(ids, id); |
652 | if (IS_ERR(out)) | |
653 | goto err1; | |
7ca7e564 | 654 | |
1da177e4 | 655 | spin_lock(&out->lock); |
4d2bff5e | 656 | |
1da177e4 LT |
657 | /* ipc_rmid() may have already freed the ID while ipc_lock |
658 | * was spinning: here verify that the structure is still valid | |
659 | */ | |
4d2bff5e DB |
660 | if (!out->deleted) |
661 | return out; | |
662 | ||
663 | spin_unlock(&out->lock); | |
664 | out = ERR_PTR(-EINVAL); | |
665 | err1: | |
666 | rcu_read_unlock(); | |
667 | return out; | |
668 | } | |
7ca7e564 | 669 | |
4d2bff5e DB |
670 | /** |
671 | * ipc_obtain_object_check | |
672 | * @ids: ipc identifier set | |
673 | * @id: ipc id to look for | |
674 | * | |
675 | * Similar to ipc_obtain_object() but also checks | |
676 | * the ipc object reference counter. | |
677 | * | |
678 | * Call inside the RCU critical section. | |
679 | * The ipc object is *not* locked on exit. | |
680 | */ | |
681 | struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id) | |
682 | { | |
683 | struct kern_ipc_perm *out = ipc_obtain_object(ids, id); | |
684 | ||
685 | if (IS_ERR(out)) | |
686 | goto out; | |
687 | ||
688 | if (ipc_checkid(out, id)) | |
689 | return ERR_PTR(-EIDRM); | |
690 | out: | |
1da177e4 LT |
691 | return out; |
692 | } | |
693 | ||
b2d75cdd PE |
694 | /** |
695 | * ipcget - Common sys_*get() code | |
696 | * @ns : namsepace | |
697 | * @ids : IPC identifier set | |
698 | * @ops : operations to be called on ipc object creation, permission checks | |
699 | * and further checks | |
700 | * @params : the parameters needed by the previous operations. | |
701 | * | |
702 | * Common routine called by sys_msgget(), sys_semget() and sys_shmget(). | |
703 | */ | |
704 | int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, | |
705 | struct ipc_ops *ops, struct ipc_params *params) | |
706 | { | |
707 | if (params->key == IPC_PRIVATE) | |
708 | return ipcget_new(ns, ids, ops, params); | |
709 | else | |
710 | return ipcget_public(ns, ids, ops, params); | |
711 | } | |
712 | ||
8f4a3809 PP |
713 | /** |
714 | * ipc_update_perm - update the permissions of an IPC. | |
715 | * @in: the permission given as input. | |
716 | * @out: the permission of the ipc to set. | |
717 | */ | |
1efdb69b | 718 | int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out) |
8f4a3809 | 719 | { |
1efdb69b EB |
720 | kuid_t uid = make_kuid(current_user_ns(), in->uid); |
721 | kgid_t gid = make_kgid(current_user_ns(), in->gid); | |
722 | if (!uid_valid(uid) || !gid_valid(gid)) | |
723 | return -EINVAL; | |
724 | ||
725 | out->uid = uid; | |
726 | out->gid = gid; | |
8f4a3809 PP |
727 | out->mode = (out->mode & ~S_IRWXUGO) |
728 | | (in->mode & S_IRWXUGO); | |
1efdb69b EB |
729 | |
730 | return 0; | |
8f4a3809 PP |
731 | } |
732 | ||
a5f75e7f | 733 | /** |
3b1c4ad3 | 734 | * ipcctl_pre_down_nolock - retrieve an ipc and check permissions for some IPC_XXX cmd |
6213cfe8 | 735 | * @ns: the ipc namespace |
a5f75e7f PP |
736 | * @ids: the table of ids where to look for the ipc |
737 | * @id: the id of the ipc to retrieve | |
738 | * @cmd: the cmd to check | |
739 | * @perm: the permission to set | |
740 | * @extra_perm: one extra permission parameter used by msq | |
741 | * | |
742 | * This function does some common audit and permissions check for some IPC_XXX | |
743 | * cmd and is called from semctl_down, shmctl_down and msgctl_down. | |
744 | * It must be called without any lock held and | |
745 | * - retrieves the ipc with the given id in the given table. | |
746 | * - performs some audit and permission check, depending on the given cmd | |
3b1c4ad3 | 747 | * - returns a pointer to the ipc object or otherwise, the corresponding error. |
7b4cc5d8 | 748 | * |
d9a605e4 | 749 | * Call holding the both the rwsem and the rcu read lock. |
a5f75e7f | 750 | */ |
444d0f62 | 751 | struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns, |
3b1c4ad3 DB |
752 | struct ipc_ids *ids, int id, int cmd, |
753 | struct ipc64_perm *perm, int extra_perm) | |
444d0f62 | 754 | { |
1efdb69b | 755 | kuid_t euid; |
444d0f62 DB |
756 | int err = -EPERM; |
757 | struct kern_ipc_perm *ipcp; | |
a5f75e7f | 758 | |
444d0f62 | 759 | ipcp = ipc_obtain_object_check(ids, id); |
a5f75e7f PP |
760 | if (IS_ERR(ipcp)) { |
761 | err = PTR_ERR(ipcp); | |
7b4cc5d8 | 762 | goto err; |
a5f75e7f PP |
763 | } |
764 | ||
a33e6751 | 765 | audit_ipc_obj(ipcp); |
e816f370 AV |
766 | if (cmd == IPC_SET) |
767 | audit_ipc_set_perm(extra_perm, perm->uid, | |
444d0f62 | 768 | perm->gid, perm->mode); |
414c0708 DH |
769 | |
770 | euid = current_euid(); | |
1efdb69b | 771 | if (uid_eq(euid, ipcp->cuid) || uid_eq(euid, ipcp->uid) || |
b0e77598 | 772 | ns_capable(ns->user_ns, CAP_SYS_ADMIN)) |
7b4cc5d8 DB |
773 | return ipcp; /* successful lookup */ |
774 | err: | |
a5f75e7f PP |
775 | return ERR_PTR(err); |
776 | } | |
777 | ||
c1d7e01d | 778 | #ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION |
1da177e4 LT |
779 | |
780 | ||
781 | /** | |
782 | * ipc_parse_version - IPC call version | |
783 | * @cmd: pointer to command | |
784 | * | |
785 | * Return IPC_64 for new style IPC and IPC_OLD for old style IPC. | |
72fd4a35 | 786 | * The @cmd value is turned from an encoding command and version into |
1da177e4 LT |
787 | * just the command code. |
788 | */ | |
789 | ||
790 | int ipc_parse_version (int *cmd) | |
791 | { | |
792 | if (*cmd & IPC_64) { | |
793 | *cmd ^= IPC_64; | |
794 | return IPC_64; | |
795 | } else { | |
796 | return IPC_OLD; | |
797 | } | |
798 | } | |
799 | ||
c1d7e01d | 800 | #endif /* CONFIG_ARCH_WANT_IPC_PARSE_VERSION */ |
ae781774 MW |
801 | |
802 | #ifdef CONFIG_PROC_FS | |
bc1fc6d8 EB |
803 | struct ipc_proc_iter { |
804 | struct ipc_namespace *ns; | |
805 | struct ipc_proc_iface *iface; | |
806 | }; | |
807 | ||
7ca7e564 ND |
808 | /* |
809 | * This routine locks the ipc structure found at least at position pos. | |
810 | */ | |
b524b9ad AB |
811 | static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos, |
812 | loff_t *new_pos) | |
ae781774 | 813 | { |
7ca7e564 ND |
814 | struct kern_ipc_perm *ipc; |
815 | int total, id; | |
73ea4130 | 816 | |
7ca7e564 ND |
817 | total = 0; |
818 | for (id = 0; id < pos && total < ids->in_use; id++) { | |
819 | ipc = idr_find(&ids->ipcs_idr, id); | |
820 | if (ipc != NULL) | |
821 | total++; | |
822 | } | |
ae781774 | 823 | |
7ca7e564 ND |
824 | if (total >= ids->in_use) |
825 | return NULL; | |
ae781774 | 826 | |
7ca7e564 ND |
827 | for ( ; pos < IPCMNI; pos++) { |
828 | ipc = idr_find(&ids->ipcs_idr, pos); | |
829 | if (ipc != NULL) { | |
830 | *new_pos = pos + 1; | |
32a27500 DB |
831 | rcu_read_lock(); |
832 | ipc_lock_object(ipc); | |
ae781774 MW |
833 | return ipc; |
834 | } | |
835 | } | |
836 | ||
837 | /* Out of range - return NULL to terminate iteration */ | |
838 | return NULL; | |
839 | } | |
840 | ||
7ca7e564 ND |
841 | static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos) |
842 | { | |
843 | struct ipc_proc_iter *iter = s->private; | |
844 | struct ipc_proc_iface *iface = iter->iface; | |
845 | struct kern_ipc_perm *ipc = it; | |
846 | ||
847 | /* If we had an ipc id locked before, unlock it */ | |
848 | if (ipc && ipc != SEQ_START_TOKEN) | |
849 | ipc_unlock(ipc); | |
850 | ||
ed2ddbf8 | 851 | return sysvipc_find_ipc(&iter->ns->ids[iface->ids], *pos, pos); |
7ca7e564 ND |
852 | } |
853 | ||
ae781774 | 854 | /* |
f4566f04 ND |
855 | * File positions: pos 0 -> header, pos n -> ipc id = n - 1. |
856 | * SeqFile iterator: iterator value locked ipc pointer or SEQ_TOKEN_START. | |
ae781774 MW |
857 | */ |
858 | static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos) | |
859 | { | |
bc1fc6d8 EB |
860 | struct ipc_proc_iter *iter = s->private; |
861 | struct ipc_proc_iface *iface = iter->iface; | |
73ea4130 KK |
862 | struct ipc_ids *ids; |
863 | ||
ed2ddbf8 | 864 | ids = &iter->ns->ids[iface->ids]; |
ae781774 MW |
865 | |
866 | /* | |
867 | * Take the lock - this will be released by the corresponding | |
868 | * call to stop(). | |
869 | */ | |
d9a605e4 | 870 | down_read(&ids->rwsem); |
ae781774 MW |
871 | |
872 | /* pos < 0 is invalid */ | |
873 | if (*pos < 0) | |
874 | return NULL; | |
875 | ||
876 | /* pos == 0 means header */ | |
877 | if (*pos == 0) | |
878 | return SEQ_START_TOKEN; | |
879 | ||
880 | /* Find the (pos-1)th ipc */ | |
7ca7e564 | 881 | return sysvipc_find_ipc(ids, *pos - 1, pos); |
ae781774 MW |
882 | } |
883 | ||
884 | static void sysvipc_proc_stop(struct seq_file *s, void *it) | |
885 | { | |
886 | struct kern_ipc_perm *ipc = it; | |
bc1fc6d8 EB |
887 | struct ipc_proc_iter *iter = s->private; |
888 | struct ipc_proc_iface *iface = iter->iface; | |
73ea4130 | 889 | struct ipc_ids *ids; |
ae781774 | 890 | |
f4566f04 | 891 | /* If we had a locked structure, release it */ |
ae781774 MW |
892 | if (ipc && ipc != SEQ_START_TOKEN) |
893 | ipc_unlock(ipc); | |
894 | ||
ed2ddbf8 | 895 | ids = &iter->ns->ids[iface->ids]; |
ae781774 | 896 | /* Release the lock we took in start() */ |
d9a605e4 | 897 | up_read(&ids->rwsem); |
ae781774 MW |
898 | } |
899 | ||
900 | static int sysvipc_proc_show(struct seq_file *s, void *it) | |
901 | { | |
bc1fc6d8 EB |
902 | struct ipc_proc_iter *iter = s->private; |
903 | struct ipc_proc_iface *iface = iter->iface; | |
ae781774 MW |
904 | |
905 | if (it == SEQ_START_TOKEN) | |
906 | return seq_puts(s, iface->header); | |
907 | ||
908 | return iface->show(s, it); | |
909 | } | |
910 | ||
88e9d34c | 911 | static const struct seq_operations sysvipc_proc_seqops = { |
ae781774 MW |
912 | .start = sysvipc_proc_start, |
913 | .stop = sysvipc_proc_stop, | |
914 | .next = sysvipc_proc_next, | |
915 | .show = sysvipc_proc_show, | |
916 | }; | |
917 | ||
bc1fc6d8 EB |
918 | static int sysvipc_proc_open(struct inode *inode, struct file *file) |
919 | { | |
ae781774 MW |
920 | int ret; |
921 | struct seq_file *seq; | |
bc1fc6d8 EB |
922 | struct ipc_proc_iter *iter; |
923 | ||
924 | ret = -ENOMEM; | |
925 | iter = kmalloc(sizeof(*iter), GFP_KERNEL); | |
926 | if (!iter) | |
927 | goto out; | |
ae781774 MW |
928 | |
929 | ret = seq_open(file, &sysvipc_proc_seqops); | |
bc1fc6d8 EB |
930 | if (ret) |
931 | goto out_kfree; | |
932 | ||
933 | seq = file->private_data; | |
934 | seq->private = iter; | |
935 | ||
d9dda78b | 936 | iter->iface = PDE_DATA(inode); |
bc1fc6d8 EB |
937 | iter->ns = get_ipc_ns(current->nsproxy->ipc_ns); |
938 | out: | |
ae781774 | 939 | return ret; |
bc1fc6d8 EB |
940 | out_kfree: |
941 | kfree(iter); | |
942 | goto out; | |
943 | } | |
944 | ||
945 | static int sysvipc_proc_release(struct inode *inode, struct file *file) | |
946 | { | |
947 | struct seq_file *seq = file->private_data; | |
948 | struct ipc_proc_iter *iter = seq->private; | |
949 | put_ipc_ns(iter->ns); | |
950 | return seq_release_private(inode, file); | |
ae781774 MW |
951 | } |
952 | ||
9a32144e | 953 | static const struct file_operations sysvipc_proc_fops = { |
ae781774 MW |
954 | .open = sysvipc_proc_open, |
955 | .read = seq_read, | |
956 | .llseek = seq_lseek, | |
bc1fc6d8 | 957 | .release = sysvipc_proc_release, |
ae781774 MW |
958 | }; |
959 | #endif /* CONFIG_PROC_FS */ |