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> | |
1da177e4 LT |
18 | */ |
19 | ||
1da177e4 LT |
20 | #include <linux/mm.h> |
21 | #include <linux/shm.h> | |
22 | #include <linux/init.h> | |
23 | #include <linux/msg.h> | |
1da177e4 LT |
24 | #include <linux/vmalloc.h> |
25 | #include <linux/slab.h> | |
c59ede7b | 26 | #include <linux/capability.h> |
1da177e4 LT |
27 | #include <linux/highuid.h> |
28 | #include <linux/security.h> | |
29 | #include <linux/rcupdate.h> | |
30 | #include <linux/workqueue.h> | |
ae781774 MW |
31 | #include <linux/seq_file.h> |
32 | #include <linux/proc_fs.h> | |
073115d6 | 33 | #include <linux/audit.h> |
73ea4130 | 34 | #include <linux/nsproxy.h> |
3e148c79 | 35 | #include <linux/rwsem.h> |
b6b337ad | 36 | #include <linux/memory.h> |
ae5e1b22 | 37 | #include <linux/ipc_namespace.h> |
1da177e4 LT |
38 | |
39 | #include <asm/unistd.h> | |
40 | ||
41 | #include "util.h" | |
42 | ||
ae781774 MW |
43 | struct ipc_proc_iface { |
44 | const char *path; | |
45 | const char *header; | |
73ea4130 | 46 | int ids; |
ae781774 MW |
47 | int (*show)(struct seq_file *, void *); |
48 | }; | |
49 | ||
b6b337ad ND |
50 | #ifdef CONFIG_MEMORY_HOTPLUG |
51 | ||
424450c1 ND |
52 | static void ipc_memory_notifier(struct work_struct *work) |
53 | { | |
54 | ipcns_notify(IPCNS_MEMCHANGED); | |
55 | } | |
56 | ||
57 | static DECLARE_WORK(ipc_memory_wq, ipc_memory_notifier); | |
58 | ||
59 | ||
b6b337ad ND |
60 | static int ipc_memory_callback(struct notifier_block *self, |
61 | unsigned long action, void *arg) | |
62 | { | |
63 | switch (action) { | |
64 | case MEM_ONLINE: /* memory successfully brought online */ | |
65 | case MEM_OFFLINE: /* or offline: it's time to recompute msgmni */ | |
66 | /* | |
67 | * This is done by invoking the ipcns notifier chain with the | |
68 | * IPC_MEMCHANGED event. | |
424450c1 ND |
69 | * In order not to keep the lock on the hotplug memory chain |
70 | * for too long, queue a work item that will, when waken up, | |
71 | * activate the ipcns notification chain. | |
72 | * No need to keep several ipc work items on the queue. | |
b6b337ad | 73 | */ |
424450c1 ND |
74 | if (!work_pending(&ipc_memory_wq)) |
75 | schedule_work(&ipc_memory_wq); | |
b6b337ad ND |
76 | break; |
77 | case MEM_GOING_ONLINE: | |
78 | case MEM_GOING_OFFLINE: | |
79 | case MEM_CANCEL_ONLINE: | |
80 | case MEM_CANCEL_OFFLINE: | |
81 | default: | |
82 | break; | |
83 | } | |
84 | ||
85 | return NOTIFY_OK; | |
86 | } | |
87 | ||
88 | #endif /* CONFIG_MEMORY_HOTPLUG */ | |
89 | ||
1da177e4 LT |
90 | /** |
91 | * ipc_init - initialise IPC subsystem | |
92 | * | |
93 | * The various system5 IPC resources (semaphores, messages and shared | |
72fd4a35 | 94 | * memory) are initialised |
b6b337ad ND |
95 | * A callback routine is registered into the memory hotplug notifier |
96 | * chain: since msgmni scales to lowmem this callback routine will be | |
97 | * called upon successful memory add / remove to recompute msmgni. | |
1da177e4 LT |
98 | */ |
99 | ||
100 | static int __init ipc_init(void) | |
101 | { | |
102 | sem_init(); | |
103 | msg_init(); | |
104 | shm_init(); | |
b6b337ad ND |
105 | hotplug_memory_notifier(ipc_memory_callback, IPC_CALLBACK_PRI); |
106 | register_ipcns_notifier(&init_ipc_ns); | |
1da177e4 LT |
107 | return 0; |
108 | } | |
109 | __initcall(ipc_init); | |
110 | ||
111 | /** | |
112 | * ipc_init_ids - initialise IPC identifiers | |
113 | * @ids: Identifier set | |
1da177e4 | 114 | * |
7ca7e564 ND |
115 | * Set up the sequence range to use for the ipc identifier range (limited |
116 | * below IPCMNI) then initialise the ids idr. | |
1da177e4 LT |
117 | */ |
118 | ||
7ca7e564 | 119 | void ipc_init_ids(struct ipc_ids *ids) |
1da177e4 | 120 | { |
3e148c79 | 121 | init_rwsem(&ids->rw_mutex); |
1da177e4 | 122 | |
1da177e4 | 123 | ids->in_use = 0; |
1da177e4 | 124 | ids->seq = 0; |
03f59566 | 125 | ids->next_id = -1; |
1da177e4 LT |
126 | { |
127 | int seq_limit = INT_MAX/SEQ_MULTIPLIER; | |
4be929be AD |
128 | if (seq_limit > USHRT_MAX) |
129 | ids->seq_max = USHRT_MAX; | |
1da177e4 LT |
130 | else |
131 | ids->seq_max = seq_limit; | |
132 | } | |
133 | ||
7ca7e564 | 134 | idr_init(&ids->ipcs_idr); |
1da177e4 LT |
135 | } |
136 | ||
ae781774 | 137 | #ifdef CONFIG_PROC_FS |
9a32144e | 138 | static const struct file_operations sysvipc_proc_fops; |
ae781774 | 139 | /** |
72fd4a35 | 140 | * ipc_init_proc_interface - Create a proc interface for sysipc types using a seq_file interface. |
ae781774 MW |
141 | * @path: Path in procfs |
142 | * @header: Banner to be printed at the beginning of the file. | |
143 | * @ids: ipc id table to iterate. | |
144 | * @show: show routine. | |
145 | */ | |
146 | void __init ipc_init_proc_interface(const char *path, const char *header, | |
73ea4130 | 147 | int ids, int (*show)(struct seq_file *, void *)) |
ae781774 MW |
148 | { |
149 | struct proc_dir_entry *pde; | |
150 | struct ipc_proc_iface *iface; | |
151 | ||
152 | iface = kmalloc(sizeof(*iface), GFP_KERNEL); | |
153 | if (!iface) | |
154 | return; | |
155 | iface->path = path; | |
156 | iface->header = header; | |
157 | iface->ids = ids; | |
158 | iface->show = show; | |
159 | ||
6a6375db DL |
160 | pde = proc_create_data(path, |
161 | S_IRUGO, /* world readable */ | |
162 | NULL, /* parent dir */ | |
163 | &sysvipc_proc_fops, | |
164 | iface); | |
165 | if (!pde) { | |
ae781774 MW |
166 | kfree(iface); |
167 | } | |
168 | } | |
169 | #endif | |
170 | ||
1da177e4 LT |
171 | /** |
172 | * ipc_findkey - find a key in an ipc identifier set | |
173 | * @ids: Identifier set | |
174 | * @key: The key to find | |
175 | * | |
3e148c79 | 176 | * Requires ipc_ids.rw_mutex locked. |
7ca7e564 ND |
177 | * Returns the LOCKED pointer to the ipc structure if found or NULL |
178 | * if not. | |
f4566f04 | 179 | * If key is found ipc points to the owning ipc structure |
1da177e4 LT |
180 | */ |
181 | ||
7748dbfa | 182 | static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key) |
1da177e4 | 183 | { |
7ca7e564 ND |
184 | struct kern_ipc_perm *ipc; |
185 | int next_id; | |
186 | int total; | |
1da177e4 | 187 | |
7ca7e564 ND |
188 | for (total = 0, next_id = 0; total < ids->in_use; next_id++) { |
189 | ipc = idr_find(&ids->ipcs_idr, next_id); | |
190 | ||
191 | if (ipc == NULL) | |
1da177e4 | 192 | continue; |
7ca7e564 ND |
193 | |
194 | if (ipc->key != key) { | |
195 | total++; | |
196 | continue; | |
197 | } | |
198 | ||
199 | ipc_lock_by_ptr(ipc); | |
200 | return ipc; | |
1da177e4 | 201 | } |
7ca7e564 ND |
202 | |
203 | return NULL; | |
1da177e4 LT |
204 | } |
205 | ||
7ca7e564 ND |
206 | /** |
207 | * ipc_get_maxid - get the last assigned id | |
208 | * @ids: IPC identifier set | |
209 | * | |
3e148c79 | 210 | * Called with ipc_ids.rw_mutex held. |
1da177e4 | 211 | */ |
1da177e4 | 212 | |
7ca7e564 ND |
213 | int ipc_get_maxid(struct ipc_ids *ids) |
214 | { | |
215 | struct kern_ipc_perm *ipc; | |
216 | int max_id = -1; | |
217 | int total, id; | |
218 | ||
219 | if (ids->in_use == 0) | |
220 | return -1; | |
1da177e4 | 221 | |
7ca7e564 ND |
222 | if (ids->in_use == IPCMNI) |
223 | return IPCMNI - 1; | |
224 | ||
225 | /* Look for the last assigned id */ | |
226 | total = 0; | |
227 | for (id = 0; id < IPCMNI && total < ids->in_use; id++) { | |
228 | ipc = idr_find(&ids->ipcs_idr, id); | |
229 | if (ipc != NULL) { | |
230 | max_id = id; | |
231 | total++; | |
232 | } | |
233 | } | |
234 | return max_id; | |
1da177e4 LT |
235 | } |
236 | ||
237 | /** | |
238 | * ipc_addid - add an IPC identifier | |
239 | * @ids: IPC identifier set | |
240 | * @new: new IPC permission set | |
7ca7e564 | 241 | * @size: limit for the number of used ids |
1da177e4 | 242 | * |
f4566f04 | 243 | * Add an entry 'new' to the IPC ids idr. The permissions object is |
1da177e4 | 244 | * initialised and the first free entry is set up and the id assigned |
f4566f04 | 245 | * is returned. The 'new' entry is returned in a locked state on success. |
283bb7fa | 246 | * On failure the entry is not locked and a negative err-code is returned. |
1da177e4 | 247 | * |
3e148c79 | 248 | * Called with ipc_ids.rw_mutex held as a writer. |
1da177e4 LT |
249 | */ |
250 | ||
251 | int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size) | |
252 | { | |
1efdb69b EB |
253 | kuid_t euid; |
254 | kgid_t egid; | |
54924ea3 | 255 | int id; |
03f59566 | 256 | int next_id = ids->next_id; |
1da177e4 | 257 | |
7ca7e564 ND |
258 | if (size > IPCMNI) |
259 | size = IPCMNI; | |
260 | ||
261 | if (ids->in_use >= size) | |
283bb7fa | 262 | return -ENOSPC; |
7ca7e564 | 263 | |
54924ea3 TH |
264 | idr_preload(GFP_KERNEL); |
265 | ||
e00b4ff7 ND |
266 | spin_lock_init(&new->lock); |
267 | new->deleted = 0; | |
268 | rcu_read_lock(); | |
269 | spin_lock(&new->lock); | |
270 | ||
54924ea3 TH |
271 | id = idr_alloc(&ids->ipcs_idr, new, |
272 | (next_id < 0) ? 0 : ipcid_to_idx(next_id), 0, | |
273 | GFP_NOWAIT); | |
274 | idr_preload_end(); | |
275 | if (id < 0) { | |
e00b4ff7 ND |
276 | spin_unlock(&new->lock); |
277 | rcu_read_unlock(); | |
54924ea3 | 278 | return id; |
e00b4ff7 | 279 | } |
7ca7e564 | 280 | |
1da177e4 | 281 | ids->in_use++; |
1da177e4 | 282 | |
414c0708 DH |
283 | current_euid_egid(&euid, &egid); |
284 | new->cuid = new->uid = euid; | |
285 | new->gid = new->cgid = egid; | |
1da177e4 | 286 | |
03f59566 SK |
287 | if (next_id < 0) { |
288 | new->seq = ids->seq++; | |
289 | if (ids->seq > ids->seq_max) | |
290 | ids->seq = 0; | |
291 | } else { | |
292 | new->seq = ipcid_to_seqx(next_id); | |
293 | ids->next_id = -1; | |
294 | } | |
1da177e4 | 295 | |
48dea404 | 296 | new->id = ipc_buildid(id, new->seq); |
1da177e4 LT |
297 | return id; |
298 | } | |
299 | ||
7748dbfa ND |
300 | /** |
301 | * ipcget_new - create a new ipc object | |
302 | * @ns: namespace | |
f4566f04 | 303 | * @ids: IPC identifer set |
7748dbfa ND |
304 | * @ops: the actual creation routine to call |
305 | * @params: its parameters | |
306 | * | |
f4566f04 ND |
307 | * This routine is called by sys_msgget, sys_semget() and sys_shmget() |
308 | * when the key is IPC_PRIVATE. | |
7748dbfa | 309 | */ |
b2d75cdd | 310 | static int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids, |
7748dbfa ND |
311 | struct ipc_ops *ops, struct ipc_params *params) |
312 | { | |
313 | int err; | |
7748dbfa | 314 | |
3e148c79 | 315 | down_write(&ids->rw_mutex); |
7748dbfa | 316 | err = ops->getnew(ns, params); |
3e148c79 | 317 | up_write(&ids->rw_mutex); |
7748dbfa ND |
318 | return err; |
319 | } | |
320 | ||
321 | /** | |
322 | * ipc_check_perms - check security and permissions for an IPC | |
6213cfe8 | 323 | * @ns: IPC namespace |
7748dbfa | 324 | * @ipcp: ipc permission set |
7748dbfa ND |
325 | * @ops: the actual security routine to call |
326 | * @params: its parameters | |
f4566f04 ND |
327 | * |
328 | * This routine is called by sys_msgget(), sys_semget() and sys_shmget() | |
329 | * when the key is not IPC_PRIVATE and that key already exists in the | |
330 | * ids IDR. | |
331 | * | |
332 | * On success, the IPC id is returned. | |
333 | * | |
3e148c79 | 334 | * It is called with ipc_ids.rw_mutex and ipcp->lock held. |
7748dbfa | 335 | */ |
b0e77598 SH |
336 | static int ipc_check_perms(struct ipc_namespace *ns, |
337 | struct kern_ipc_perm *ipcp, | |
338 | struct ipc_ops *ops, | |
339 | struct ipc_params *params) | |
7748dbfa ND |
340 | { |
341 | int err; | |
342 | ||
b0e77598 | 343 | if (ipcperms(ns, ipcp, params->flg)) |
7748dbfa ND |
344 | err = -EACCES; |
345 | else { | |
346 | err = ops->associate(ipcp, params->flg); | |
347 | if (!err) | |
348 | err = ipcp->id; | |
349 | } | |
350 | ||
351 | return err; | |
352 | } | |
353 | ||
354 | /** | |
355 | * ipcget_public - get an ipc object or create a new one | |
356 | * @ns: namespace | |
f4566f04 | 357 | * @ids: IPC identifer set |
7748dbfa ND |
358 | * @ops: the actual creation routine to call |
359 | * @params: its parameters | |
360 | * | |
f4566f04 ND |
361 | * This routine is called by sys_msgget, sys_semget() and sys_shmget() |
362 | * when the key is not IPC_PRIVATE. | |
363 | * It adds a new entry if the key is not found and does some permission | |
364 | * / security checkings if the key is found. | |
365 | * | |
366 | * On success, the ipc id is returned. | |
7748dbfa | 367 | */ |
b2d75cdd | 368 | static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids, |
7748dbfa ND |
369 | struct ipc_ops *ops, struct ipc_params *params) |
370 | { | |
371 | struct kern_ipc_perm *ipcp; | |
372 | int flg = params->flg; | |
373 | int err; | |
7748dbfa | 374 | |
3e148c79 ND |
375 | /* |
376 | * Take the lock as a writer since we are potentially going to add | |
377 | * a new entry + read locks are not "upgradable" | |
378 | */ | |
379 | down_write(&ids->rw_mutex); | |
7748dbfa ND |
380 | ipcp = ipc_findkey(ids, params->key); |
381 | if (ipcp == NULL) { | |
382 | /* key not used */ | |
383 | if (!(flg & IPC_CREAT)) | |
384 | err = -ENOENT; | |
7748dbfa ND |
385 | else |
386 | err = ops->getnew(ns, params); | |
387 | } else { | |
388 | /* ipc object has been locked by ipc_findkey() */ | |
389 | ||
390 | if (flg & IPC_CREAT && flg & IPC_EXCL) | |
391 | err = -EEXIST; | |
392 | else { | |
393 | err = 0; | |
394 | if (ops->more_checks) | |
395 | err = ops->more_checks(ipcp, params); | |
396 | if (!err) | |
f4566f04 ND |
397 | /* |
398 | * ipc_check_perms returns the IPC id on | |
399 | * success | |
400 | */ | |
b0e77598 | 401 | err = ipc_check_perms(ns, ipcp, ops, params); |
7748dbfa ND |
402 | } |
403 | ipc_unlock(ipcp); | |
404 | } | |
3e148c79 | 405 | up_write(&ids->rw_mutex); |
7748dbfa ND |
406 | |
407 | return err; | |
408 | } | |
409 | ||
410 | ||
1da177e4 LT |
411 | /** |
412 | * ipc_rmid - remove an IPC identifier | |
f4566f04 ND |
413 | * @ids: IPC identifier set |
414 | * @ipcp: ipc perm structure containing the identifier to remove | |
1da177e4 | 415 | * |
3e148c79 ND |
416 | * ipc_ids.rw_mutex (as a writer) and the spinlock for this ID are held |
417 | * before this function is called, and remain locked on the exit. | |
1da177e4 LT |
418 | */ |
419 | ||
7ca7e564 | 420 | void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp) |
1da177e4 | 421 | { |
ce621f5b | 422 | int lid = ipcid_to_idx(ipcp->id); |
7ca7e564 ND |
423 | |
424 | idr_remove(&ids->ipcs_idr, lid); | |
1da177e4 | 425 | |
1da177e4 LT |
426 | ids->in_use--; |
427 | ||
7ca7e564 ND |
428 | ipcp->deleted = 1; |
429 | ||
430 | return; | |
1da177e4 LT |
431 | } |
432 | ||
433 | /** | |
434 | * ipc_alloc - allocate ipc space | |
435 | * @size: size desired | |
436 | * | |
437 | * Allocate memory from the appropriate pools and return a pointer to it. | |
438 | * NULL is returned if the allocation fails | |
439 | */ | |
440 | ||
441 | void* ipc_alloc(int size) | |
442 | { | |
443 | void* out; | |
444 | if(size > PAGE_SIZE) | |
445 | out = vmalloc(size); | |
446 | else | |
447 | out = kmalloc(size, GFP_KERNEL); | |
448 | return out; | |
449 | } | |
450 | ||
451 | /** | |
452 | * ipc_free - free ipc space | |
453 | * @ptr: pointer returned by ipc_alloc | |
454 | * @size: size of block | |
455 | * | |
72fd4a35 | 456 | * Free a block created with ipc_alloc(). The caller must know the size |
1da177e4 LT |
457 | * used in the allocation call. |
458 | */ | |
459 | ||
460 | void ipc_free(void* ptr, int size) | |
461 | { | |
462 | if(size > PAGE_SIZE) | |
463 | vfree(ptr); | |
464 | else | |
465 | kfree(ptr); | |
466 | } | |
467 | ||
468 | /* | |
469 | * rcu allocations: | |
470 | * There are three headers that are prepended to the actual allocation: | |
471 | * - during use: ipc_rcu_hdr. | |
472 | * - during the rcu grace period: ipc_rcu_grace. | |
473 | * - [only if vmalloc]: ipc_rcu_sched. | |
474 | * Their lifetime doesn't overlap, thus the headers share the same memory. | |
475 | * Unlike a normal union, they are right-aligned, thus some container_of | |
476 | * forward/backward casting is necessary: | |
477 | */ | |
478 | struct ipc_rcu_hdr | |
479 | { | |
480 | int refcount; | |
481 | int is_vmalloc; | |
482 | void *data[0]; | |
483 | }; | |
484 | ||
485 | ||
486 | struct ipc_rcu_grace | |
487 | { | |
488 | struct rcu_head rcu; | |
489 | /* "void *" makes sure alignment of following data is sane. */ | |
490 | void *data[0]; | |
491 | }; | |
492 | ||
493 | struct ipc_rcu_sched | |
494 | { | |
495 | struct work_struct work; | |
496 | /* "void *" makes sure alignment of following data is sane. */ | |
497 | void *data[0]; | |
498 | }; | |
499 | ||
500 | #define HDRLEN_KMALLOC (sizeof(struct ipc_rcu_grace) > sizeof(struct ipc_rcu_hdr) ? \ | |
501 | sizeof(struct ipc_rcu_grace) : sizeof(struct ipc_rcu_hdr)) | |
502 | #define HDRLEN_VMALLOC (sizeof(struct ipc_rcu_sched) > HDRLEN_KMALLOC ? \ | |
503 | sizeof(struct ipc_rcu_sched) : HDRLEN_KMALLOC) | |
504 | ||
505 | static inline int rcu_use_vmalloc(int size) | |
506 | { | |
507 | /* Too big for a single page? */ | |
508 | if (HDRLEN_KMALLOC + size > PAGE_SIZE) | |
509 | return 1; | |
510 | return 0; | |
511 | } | |
512 | ||
513 | /** | |
514 | * ipc_rcu_alloc - allocate ipc and rcu space | |
515 | * @size: size desired | |
516 | * | |
517 | * Allocate memory for the rcu header structure + the object. | |
518 | * Returns the pointer to the object. | |
519 | * NULL is returned if the allocation fails. | |
520 | */ | |
521 | ||
522 | void* ipc_rcu_alloc(int size) | |
523 | { | |
524 | void* out; | |
525 | /* | |
526 | * We prepend the allocation with the rcu struct, and | |
527 | * workqueue if necessary (for vmalloc). | |
528 | */ | |
529 | if (rcu_use_vmalloc(size)) { | |
530 | out = vmalloc(HDRLEN_VMALLOC + size); | |
531 | if (out) { | |
532 | out += HDRLEN_VMALLOC; | |
533 | container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 1; | |
534 | container_of(out, struct ipc_rcu_hdr, data)->refcount = 1; | |
535 | } | |
536 | } else { | |
537 | out = kmalloc(HDRLEN_KMALLOC + size, GFP_KERNEL); | |
538 | if (out) { | |
539 | out += HDRLEN_KMALLOC; | |
540 | container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 0; | |
541 | container_of(out, struct ipc_rcu_hdr, data)->refcount = 1; | |
542 | } | |
543 | } | |
544 | ||
545 | return out; | |
546 | } | |
547 | ||
548 | void ipc_rcu_getref(void *ptr) | |
549 | { | |
550 | container_of(ptr, struct ipc_rcu_hdr, data)->refcount++; | |
551 | } | |
552 | ||
65f27f38 DH |
553 | static void ipc_do_vfree(struct work_struct *work) |
554 | { | |
555 | vfree(container_of(work, struct ipc_rcu_sched, work)); | |
556 | } | |
557 | ||
1da177e4 | 558 | /** |
1e5d5331 RD |
559 | * ipc_schedule_free - free ipc + rcu space |
560 | * @head: RCU callback structure for queued work | |
1da177e4 LT |
561 | * |
562 | * Since RCU callback function is called in bh, | |
72fd4a35 | 563 | * we need to defer the vfree to schedule_work(). |
1da177e4 LT |
564 | */ |
565 | static void ipc_schedule_free(struct rcu_head *head) | |
566 | { | |
f4566f04 ND |
567 | struct ipc_rcu_grace *grace; |
568 | struct ipc_rcu_sched *sched; | |
569 | ||
570 | grace = container_of(head, struct ipc_rcu_grace, rcu); | |
571 | sched = container_of(&(grace->data[0]), struct ipc_rcu_sched, | |
572 | data[0]); | |
1da177e4 | 573 | |
65f27f38 | 574 | INIT_WORK(&sched->work, ipc_do_vfree); |
1da177e4 LT |
575 | schedule_work(&sched->work); |
576 | } | |
577 | ||
1da177e4 LT |
578 | void ipc_rcu_putref(void *ptr) |
579 | { | |
580 | if (--container_of(ptr, struct ipc_rcu_hdr, data)->refcount > 0) | |
581 | return; | |
582 | ||
583 | if (container_of(ptr, struct ipc_rcu_hdr, data)->is_vmalloc) { | |
584 | call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu, | |
585 | ipc_schedule_free); | |
586 | } else { | |
d4ee9aa3 | 587 | kfree_rcu(container_of(ptr, struct ipc_rcu_grace, data), rcu); |
1da177e4 LT |
588 | } |
589 | } | |
590 | ||
591 | /** | |
592 | * ipcperms - check IPC permissions | |
6213cfe8 | 593 | * @ns: IPC namespace |
1da177e4 LT |
594 | * @ipcp: IPC permission set |
595 | * @flag: desired permission set. | |
596 | * | |
597 | * Check user, group, other permissions for access | |
598 | * to ipc resources. return 0 if allowed | |
b0e77598 SH |
599 | * |
600 | * @flag will most probably be 0 or S_...UGO from <linux/stat.h> | |
1da177e4 LT |
601 | */ |
602 | ||
b0e77598 SH |
603 | int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flag) |
604 | { | |
1efdb69b | 605 | kuid_t euid = current_euid(); |
a33e6751 | 606 | int requested_mode, granted_mode; |
1da177e4 | 607 | |
a33e6751 | 608 | audit_ipc_obj(ipcp); |
1da177e4 LT |
609 | requested_mode = (flag >> 6) | (flag >> 3) | flag; |
610 | granted_mode = ipcp->mode; | |
1efdb69b EB |
611 | if (uid_eq(euid, ipcp->cuid) || |
612 | uid_eq(euid, ipcp->uid)) | |
1da177e4 LT |
613 | granted_mode >>= 6; |
614 | else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid)) | |
615 | granted_mode >>= 3; | |
616 | /* is there some bit set in requested_mode but not in granted_mode? */ | |
617 | if ((requested_mode & ~granted_mode & 0007) && | |
b0e77598 | 618 | !ns_capable(ns->user_ns, CAP_IPC_OWNER)) |
1da177e4 LT |
619 | return -1; |
620 | ||
621 | return security_ipc_permission(ipcp, flag); | |
622 | } | |
623 | ||
624 | /* | |
625 | * Functions to convert between the kern_ipc_perm structure and the | |
626 | * old/new ipc_perm structures | |
627 | */ | |
628 | ||
629 | /** | |
630 | * kernel_to_ipc64_perm - convert kernel ipc permissions to user | |
631 | * @in: kernel permissions | |
632 | * @out: new style IPC permissions | |
633 | * | |
72fd4a35 RD |
634 | * Turn the kernel object @in into a set of permissions descriptions |
635 | * for returning to userspace (@out). | |
1da177e4 LT |
636 | */ |
637 | ||
638 | ||
639 | void kernel_to_ipc64_perm (struct kern_ipc_perm *in, struct ipc64_perm *out) | |
640 | { | |
641 | out->key = in->key; | |
1efdb69b EB |
642 | out->uid = from_kuid_munged(current_user_ns(), in->uid); |
643 | out->gid = from_kgid_munged(current_user_ns(), in->gid); | |
644 | out->cuid = from_kuid_munged(current_user_ns(), in->cuid); | |
645 | out->cgid = from_kgid_munged(current_user_ns(), in->cgid); | |
1da177e4 LT |
646 | out->mode = in->mode; |
647 | out->seq = in->seq; | |
648 | } | |
649 | ||
650 | /** | |
f4566f04 | 651 | * ipc64_perm_to_ipc_perm - convert new ipc permissions to old |
1da177e4 LT |
652 | * @in: new style IPC permissions |
653 | * @out: old style IPC permissions | |
654 | * | |
72fd4a35 RD |
655 | * Turn the new style permissions object @in into a compatibility |
656 | * object and store it into the @out pointer. | |
1da177e4 LT |
657 | */ |
658 | ||
659 | void ipc64_perm_to_ipc_perm (struct ipc64_perm *in, struct ipc_perm *out) | |
660 | { | |
661 | out->key = in->key; | |
662 | SET_UID(out->uid, in->uid); | |
663 | SET_GID(out->gid, in->gid); | |
664 | SET_UID(out->cuid, in->cuid); | |
665 | SET_GID(out->cgid, in->cgid); | |
666 | out->mode = in->mode; | |
667 | out->seq = in->seq; | |
668 | } | |
669 | ||
f4566f04 | 670 | /** |
3e148c79 | 671 | * ipc_lock - Lock an ipc structure without rw_mutex held |
f4566f04 ND |
672 | * @ids: IPC identifier set |
673 | * @id: ipc id to look for | |
674 | * | |
675 | * Look for an id in the ipc ids idr and lock the associated ipc object. | |
676 | * | |
f4566f04 ND |
677 | * The ipc object is locked on exit. |
678 | */ | |
679 | ||
7ca7e564 | 680 | struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id) |
1da177e4 | 681 | { |
7ca7e564 | 682 | struct kern_ipc_perm *out; |
ce621f5b | 683 | int lid = ipcid_to_idx(id); |
1da177e4 LT |
684 | |
685 | rcu_read_lock(); | |
7ca7e564 ND |
686 | out = idr_find(&ids->ipcs_idr, lid); |
687 | if (out == NULL) { | |
1da177e4 | 688 | rcu_read_unlock(); |
023a5355 | 689 | return ERR_PTR(-EINVAL); |
1da177e4 | 690 | } |
7ca7e564 | 691 | |
1da177e4 LT |
692 | spin_lock(&out->lock); |
693 | ||
694 | /* ipc_rmid() may have already freed the ID while ipc_lock | |
695 | * was spinning: here verify that the structure is still valid | |
696 | */ | |
697 | if (out->deleted) { | |
698 | spin_unlock(&out->lock); | |
699 | rcu_read_unlock(); | |
023a5355 | 700 | return ERR_PTR(-EINVAL); |
1da177e4 | 701 | } |
7ca7e564 | 702 | |
1da177e4 LT |
703 | return out; |
704 | } | |
705 | ||
b2d75cdd PE |
706 | struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, int id) |
707 | { | |
708 | struct kern_ipc_perm *out; | |
709 | ||
710 | out = ipc_lock(ids, id); | |
711 | if (IS_ERR(out)) | |
712 | return out; | |
713 | ||
714 | if (ipc_checkid(out, id)) { | |
715 | ipc_unlock(out); | |
716 | return ERR_PTR(-EIDRM); | |
717 | } | |
718 | ||
719 | return out; | |
720 | } | |
721 | ||
722 | /** | |
723 | * ipcget - Common sys_*get() code | |
724 | * @ns : namsepace | |
725 | * @ids : IPC identifier set | |
726 | * @ops : operations to be called on ipc object creation, permission checks | |
727 | * and further checks | |
728 | * @params : the parameters needed by the previous operations. | |
729 | * | |
730 | * Common routine called by sys_msgget(), sys_semget() and sys_shmget(). | |
731 | */ | |
732 | int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, | |
733 | struct ipc_ops *ops, struct ipc_params *params) | |
734 | { | |
735 | if (params->key == IPC_PRIVATE) | |
736 | return ipcget_new(ns, ids, ops, params); | |
737 | else | |
738 | return ipcget_public(ns, ids, ops, params); | |
739 | } | |
740 | ||
8f4a3809 PP |
741 | /** |
742 | * ipc_update_perm - update the permissions of an IPC. | |
743 | * @in: the permission given as input. | |
744 | * @out: the permission of the ipc to set. | |
745 | */ | |
1efdb69b | 746 | int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out) |
8f4a3809 | 747 | { |
1efdb69b EB |
748 | kuid_t uid = make_kuid(current_user_ns(), in->uid); |
749 | kgid_t gid = make_kgid(current_user_ns(), in->gid); | |
750 | if (!uid_valid(uid) || !gid_valid(gid)) | |
751 | return -EINVAL; | |
752 | ||
753 | out->uid = uid; | |
754 | out->gid = gid; | |
8f4a3809 PP |
755 | out->mode = (out->mode & ~S_IRWXUGO) |
756 | | (in->mode & S_IRWXUGO); | |
1efdb69b EB |
757 | |
758 | return 0; | |
8f4a3809 PP |
759 | } |
760 | ||
a5f75e7f PP |
761 | /** |
762 | * ipcctl_pre_down - retrieve an ipc and check permissions for some IPC_XXX cmd | |
6213cfe8 | 763 | * @ns: the ipc namespace |
a5f75e7f PP |
764 | * @ids: the table of ids where to look for the ipc |
765 | * @id: the id of the ipc to retrieve | |
766 | * @cmd: the cmd to check | |
767 | * @perm: the permission to set | |
768 | * @extra_perm: one extra permission parameter used by msq | |
769 | * | |
770 | * This function does some common audit and permissions check for some IPC_XXX | |
771 | * cmd and is called from semctl_down, shmctl_down and msgctl_down. | |
772 | * It must be called without any lock held and | |
773 | * - retrieves the ipc with the given id in the given table. | |
774 | * - performs some audit and permission check, depending on the given cmd | |
775 | * - returns the ipc with both ipc and rw_mutex locks held in case of success | |
776 | * or an err-code without any lock held otherwise. | |
777 | */ | |
b0e77598 SH |
778 | struct kern_ipc_perm *ipcctl_pre_down(struct ipc_namespace *ns, |
779 | struct ipc_ids *ids, int id, int cmd, | |
a5f75e7f PP |
780 | struct ipc64_perm *perm, int extra_perm) |
781 | { | |
782 | struct kern_ipc_perm *ipcp; | |
1efdb69b | 783 | kuid_t euid; |
a5f75e7f PP |
784 | int err; |
785 | ||
786 | down_write(&ids->rw_mutex); | |
00c2bf85 | 787 | ipcp = ipc_lock_check(ids, id); |
a5f75e7f PP |
788 | if (IS_ERR(ipcp)) { |
789 | err = PTR_ERR(ipcp); | |
790 | goto out_up; | |
791 | } | |
792 | ||
a33e6751 | 793 | audit_ipc_obj(ipcp); |
e816f370 AV |
794 | if (cmd == IPC_SET) |
795 | audit_ipc_set_perm(extra_perm, perm->uid, | |
a5f75e7f | 796 | perm->gid, perm->mode); |
414c0708 DH |
797 | |
798 | euid = current_euid(); | |
1efdb69b | 799 | if (uid_eq(euid, ipcp->cuid) || uid_eq(euid, ipcp->uid) || |
b0e77598 | 800 | ns_capable(ns->user_ns, CAP_SYS_ADMIN)) |
a5f75e7f PP |
801 | return ipcp; |
802 | ||
803 | err = -EPERM; | |
a5f75e7f PP |
804 | ipc_unlock(ipcp); |
805 | out_up: | |
806 | up_write(&ids->rw_mutex); | |
807 | return ERR_PTR(err); | |
808 | } | |
809 | ||
c1d7e01d | 810 | #ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION |
1da177e4 LT |
811 | |
812 | ||
813 | /** | |
814 | * ipc_parse_version - IPC call version | |
815 | * @cmd: pointer to command | |
816 | * | |
817 | * Return IPC_64 for new style IPC and IPC_OLD for old style IPC. | |
72fd4a35 | 818 | * The @cmd value is turned from an encoding command and version into |
1da177e4 LT |
819 | * just the command code. |
820 | */ | |
821 | ||
822 | int ipc_parse_version (int *cmd) | |
823 | { | |
824 | if (*cmd & IPC_64) { | |
825 | *cmd ^= IPC_64; | |
826 | return IPC_64; | |
827 | } else { | |
828 | return IPC_OLD; | |
829 | } | |
830 | } | |
831 | ||
c1d7e01d | 832 | #endif /* CONFIG_ARCH_WANT_IPC_PARSE_VERSION */ |
ae781774 MW |
833 | |
834 | #ifdef CONFIG_PROC_FS | |
bc1fc6d8 EB |
835 | struct ipc_proc_iter { |
836 | struct ipc_namespace *ns; | |
837 | struct ipc_proc_iface *iface; | |
838 | }; | |
839 | ||
7ca7e564 ND |
840 | /* |
841 | * This routine locks the ipc structure found at least at position pos. | |
842 | */ | |
b524b9ad AB |
843 | static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos, |
844 | loff_t *new_pos) | |
ae781774 | 845 | { |
7ca7e564 ND |
846 | struct kern_ipc_perm *ipc; |
847 | int total, id; | |
73ea4130 | 848 | |
7ca7e564 ND |
849 | total = 0; |
850 | for (id = 0; id < pos && total < ids->in_use; id++) { | |
851 | ipc = idr_find(&ids->ipcs_idr, id); | |
852 | if (ipc != NULL) | |
853 | total++; | |
854 | } | |
ae781774 | 855 | |
7ca7e564 ND |
856 | if (total >= ids->in_use) |
857 | return NULL; | |
ae781774 | 858 | |
7ca7e564 ND |
859 | for ( ; pos < IPCMNI; pos++) { |
860 | ipc = idr_find(&ids->ipcs_idr, pos); | |
861 | if (ipc != NULL) { | |
862 | *new_pos = pos + 1; | |
863 | ipc_lock_by_ptr(ipc); | |
ae781774 MW |
864 | return ipc; |
865 | } | |
866 | } | |
867 | ||
868 | /* Out of range - return NULL to terminate iteration */ | |
869 | return NULL; | |
870 | } | |
871 | ||
7ca7e564 ND |
872 | static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos) |
873 | { | |
874 | struct ipc_proc_iter *iter = s->private; | |
875 | struct ipc_proc_iface *iface = iter->iface; | |
876 | struct kern_ipc_perm *ipc = it; | |
877 | ||
878 | /* If we had an ipc id locked before, unlock it */ | |
879 | if (ipc && ipc != SEQ_START_TOKEN) | |
880 | ipc_unlock(ipc); | |
881 | ||
ed2ddbf8 | 882 | return sysvipc_find_ipc(&iter->ns->ids[iface->ids], *pos, pos); |
7ca7e564 ND |
883 | } |
884 | ||
ae781774 | 885 | /* |
f4566f04 ND |
886 | * File positions: pos 0 -> header, pos n -> ipc id = n - 1. |
887 | * SeqFile iterator: iterator value locked ipc pointer or SEQ_TOKEN_START. | |
ae781774 MW |
888 | */ |
889 | static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos) | |
890 | { | |
bc1fc6d8 EB |
891 | struct ipc_proc_iter *iter = s->private; |
892 | struct ipc_proc_iface *iface = iter->iface; | |
73ea4130 KK |
893 | struct ipc_ids *ids; |
894 | ||
ed2ddbf8 | 895 | ids = &iter->ns->ids[iface->ids]; |
ae781774 MW |
896 | |
897 | /* | |
898 | * Take the lock - this will be released by the corresponding | |
899 | * call to stop(). | |
900 | */ | |
3e148c79 | 901 | down_read(&ids->rw_mutex); |
ae781774 MW |
902 | |
903 | /* pos < 0 is invalid */ | |
904 | if (*pos < 0) | |
905 | return NULL; | |
906 | ||
907 | /* pos == 0 means header */ | |
908 | if (*pos == 0) | |
909 | return SEQ_START_TOKEN; | |
910 | ||
911 | /* Find the (pos-1)th ipc */ | |
7ca7e564 | 912 | return sysvipc_find_ipc(ids, *pos - 1, pos); |
ae781774 MW |
913 | } |
914 | ||
915 | static void sysvipc_proc_stop(struct seq_file *s, void *it) | |
916 | { | |
917 | struct kern_ipc_perm *ipc = it; | |
bc1fc6d8 EB |
918 | struct ipc_proc_iter *iter = s->private; |
919 | struct ipc_proc_iface *iface = iter->iface; | |
73ea4130 | 920 | struct ipc_ids *ids; |
ae781774 | 921 | |
f4566f04 | 922 | /* If we had a locked structure, release it */ |
ae781774 MW |
923 | if (ipc && ipc != SEQ_START_TOKEN) |
924 | ipc_unlock(ipc); | |
925 | ||
ed2ddbf8 | 926 | ids = &iter->ns->ids[iface->ids]; |
ae781774 | 927 | /* Release the lock we took in start() */ |
3e148c79 | 928 | up_read(&ids->rw_mutex); |
ae781774 MW |
929 | } |
930 | ||
931 | static int sysvipc_proc_show(struct seq_file *s, void *it) | |
932 | { | |
bc1fc6d8 EB |
933 | struct ipc_proc_iter *iter = s->private; |
934 | struct ipc_proc_iface *iface = iter->iface; | |
ae781774 MW |
935 | |
936 | if (it == SEQ_START_TOKEN) | |
937 | return seq_puts(s, iface->header); | |
938 | ||
939 | return iface->show(s, it); | |
940 | } | |
941 | ||
88e9d34c | 942 | static const struct seq_operations sysvipc_proc_seqops = { |
ae781774 MW |
943 | .start = sysvipc_proc_start, |
944 | .stop = sysvipc_proc_stop, | |
945 | .next = sysvipc_proc_next, | |
946 | .show = sysvipc_proc_show, | |
947 | }; | |
948 | ||
bc1fc6d8 EB |
949 | static int sysvipc_proc_open(struct inode *inode, struct file *file) |
950 | { | |
ae781774 MW |
951 | int ret; |
952 | struct seq_file *seq; | |
bc1fc6d8 EB |
953 | struct ipc_proc_iter *iter; |
954 | ||
955 | ret = -ENOMEM; | |
956 | iter = kmalloc(sizeof(*iter), GFP_KERNEL); | |
957 | if (!iter) | |
958 | goto out; | |
ae781774 MW |
959 | |
960 | ret = seq_open(file, &sysvipc_proc_seqops); | |
bc1fc6d8 EB |
961 | if (ret) |
962 | goto out_kfree; | |
963 | ||
964 | seq = file->private_data; | |
965 | seq->private = iter; | |
966 | ||
967 | iter->iface = PDE(inode)->data; | |
968 | iter->ns = get_ipc_ns(current->nsproxy->ipc_ns); | |
969 | out: | |
ae781774 | 970 | return ret; |
bc1fc6d8 EB |
971 | out_kfree: |
972 | kfree(iter); | |
973 | goto out; | |
974 | } | |
975 | ||
976 | static int sysvipc_proc_release(struct inode *inode, struct file *file) | |
977 | { | |
978 | struct seq_file *seq = file->private_data; | |
979 | struct ipc_proc_iter *iter = seq->private; | |
980 | put_ipc_ns(iter->ns); | |
981 | return seq_release_private(inode, file); | |
ae781774 MW |
982 | } |
983 | ||
9a32144e | 984 | static const struct file_operations sysvipc_proc_fops = { |
ae781774 MW |
985 | .open = sysvipc_proc_open, |
986 | .read = seq_read, | |
987 | .llseek = seq_lseek, | |
bc1fc6d8 | 988 | .release = sysvipc_proc_release, |
ae781774 MW |
989 | }; |
990 | #endif /* CONFIG_PROC_FS */ |