ipc: get rid of ids->tables_initialized hack
[linux-2.6-block.git] / ipc / util.c
CommitLineData
b2441318 1// SPDX-License-Identifier: GPL-2.0
1da177e4
LT
2/*
3 * linux/ipc/util.c
4 * Copyright (C) 1992 Krishna Balasubramanian
5 *
6 * Sep 1997 - Call suser() last after "normal" permission checks so we
7 * get BSD style process accounting right.
8 * Occurs in several places in the IPC code.
9 * Chris Evans, <chris@ferret.lmh.ox.ac.uk>
10 * Nov 1999 - ipc helper functions, unified SMP locking
624dffcb 11 * Manfred Spraul <manfred@colorfullife.com>
1da177e4
LT
12 * Oct 2002 - One lock per IPC id. RCU ipc_free for lock-free grow_ary().
13 * Mingming Cao <cmm@us.ibm.com>
073115d6
SG
14 * Mar 2006 - support for audit of ipc object properties
15 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
73ea4130
KK
16 * Jun 2006 - namespaces ssupport
17 * OpenVZ, SWsoft Inc.
18 * Pavel Emelianov <xemul@openvz.org>
05603c44
DB
19 *
20 * General sysv ipc locking scheme:
18ccee26
DB
21 * rcu_read_lock()
22 * obtain the ipc object (kern_ipc_perm) by looking up the id in an idr
23 * tree.
24 * - perform initial checks (capabilities, auditing and permission,
25 * etc).
87ad4b0d
PM
26 * - perform read-only operations, such as INFO command, that
27 * do not demand atomicity
18ccee26
DB
28 * acquire the ipc lock (kern_ipc_perm.lock) through
29 * ipc_lock_object()
87ad4b0d
PM
30 * - perform read-only operations that demand atomicity,
31 * such as STAT command.
18ccee26
DB
32 * - perform data updates, such as SET, RMID commands and
33 * mechanism-specific operations (semop/semtimedop,
34 * msgsnd/msgrcv, shmat/shmdt).
35 * drop the ipc lock, through ipc_unlock_object().
36 * rcu_read_unlock()
37 *
38 * The ids->rwsem must be taken when:
39 * - creating, removing and iterating the existing entries in ipc
40 * identifier sets.
41 * - iterating through files under /proc/sysvipc/
42 *
43 * Note that sems have a special fast path that avoids kern_ipc_perm.lock -
44 * see sem_lock().
1da177e4
LT
45 */
46
1da177e4
LT
47#include <linux/mm.h>
48#include <linux/shm.h>
49#include <linux/init.h>
50#include <linux/msg.h>
1da177e4
LT
51#include <linux/vmalloc.h>
52#include <linux/slab.h>
8f68fa2d 53#include <linux/notifier.h>
c59ede7b 54#include <linux/capability.h>
1da177e4
LT
55#include <linux/highuid.h>
56#include <linux/security.h>
57#include <linux/rcupdate.h>
58#include <linux/workqueue.h>
ae781774
MW
59#include <linux/seq_file.h>
60#include <linux/proc_fs.h>
073115d6 61#include <linux/audit.h>
73ea4130 62#include <linux/nsproxy.h>
3e148c79 63#include <linux/rwsem.h>
b6b337ad 64#include <linux/memory.h>
ae5e1b22 65#include <linux/ipc_namespace.h>
0eb71a9d 66#include <linux/rhashtable.h>
1da177e4
LT
67
68#include <asm/unistd.h>
69
70#include "util.h"
71
ae781774
MW
72struct ipc_proc_iface {
73 const char *path;
74 const char *header;
73ea4130 75 int ids;
ae781774
MW
76 int (*show)(struct seq_file *, void *);
77};
78
1da177e4 79/**
8001c858 80 * ipc_init - initialise ipc subsystem
1da177e4 81 *
8001c858
DB
82 * The various sysv ipc resources (semaphores, messages and shared
83 * memory) are initialised.
84 *
85 * A callback routine is registered into the memory hotplug notifier
86 * chain: since msgmni scales to lowmem this callback routine will be
87 * called upon successful memory add / remove to recompute msmgni.
1da177e4 88 */
1da177e4
LT
89static int __init ipc_init(void)
90{
0cfb6aee
GK
91 int err_sem, err_msg;
92
e74a0eff 93 proc_mkdir("sysvipc", NULL);
0cfb6aee
GK
94 err_sem = sem_init();
95 WARN(err_sem, "ipc: sysv sem_init failed: %d\n", err_sem);
96 err_msg = msg_init();
97 WARN(err_msg, "ipc: sysv msg_init failed: %d\n", err_msg);
1da177e4 98 shm_init();
0cfb6aee
GK
99
100 return err_msg ? err_msg : err_sem;
1da177e4 101}
6d08a256 102device_initcall(ipc_init);
1da177e4 103
0cfb6aee
GK
104static const struct rhashtable_params ipc_kht_params = {
105 .head_offset = offsetof(struct kern_ipc_perm, khtnode),
106 .key_offset = offsetof(struct kern_ipc_perm, key),
107 .key_len = FIELD_SIZEOF(struct kern_ipc_perm, key),
108 .locks_mul = 1,
109 .automatic_shrinking = true,
110};
111
1da177e4 112/**
8001c858
DB
113 * ipc_init_ids - initialise ipc identifiers
114 * @ids: ipc identifier set
1da177e4 115 *
8001c858 116 * Set up the sequence range to use for the ipc identifier range (limited
0cfb6aee 117 * below IPCMNI) then initialise the keys hashtable and ids idr.
1da177e4 118 */
0cfb6aee 119int ipc_init_ids(struct ipc_ids *ids)
1da177e4 120{
0cfb6aee 121 int err;
1da177e4 122 ids->in_use = 0;
1da177e4 123 ids->seq = 0;
daf948c7 124 init_rwsem(&ids->rwsem);
0cfb6aee
GK
125 err = rhashtable_init(&ids->key_ht, &ipc_kht_params);
126 if (err)
127 return err;
7ca7e564 128 idr_init(&ids->ipcs_idr);
15df03c8 129 ids->max_id = -1;
b8fd9983
DB
130#ifdef CONFIG_CHECKPOINT_RESTORE
131 ids->next_id = -1;
132#endif
0cfb6aee 133 return 0;
1da177e4
LT
134}
135
ae781774 136#ifdef CONFIG_PROC_FS
9a32144e 137static const struct file_operations sysvipc_proc_fops;
ae781774 138/**
8001c858
DB
139 * ipc_init_proc_interface - create a proc interface for sysipc types using a seq_file interface.
140 * @path: Path in procfs
141 * @header: Banner to be printed at the beginning of the file.
142 * @ids: ipc id table to iterate.
143 * @show: show routine.
ae781774
MW
144 */
145void __init ipc_init_proc_interface(const char *path, const char *header,
73ea4130 146 int ids, int (*show)(struct seq_file *, void *))
ae781774
MW
147{
148 struct proc_dir_entry *pde;
149 struct ipc_proc_iface *iface;
150
151 iface = kmalloc(sizeof(*iface), GFP_KERNEL);
152 if (!iface)
153 return;
154 iface->path = path;
155 iface->header = header;
156 iface->ids = ids;
157 iface->show = show;
158
6a6375db
DL
159 pde = proc_create_data(path,
160 S_IRUGO, /* world readable */
161 NULL, /* parent dir */
162 &sysvipc_proc_fops,
163 iface);
3ab08fe2 164 if (!pde)
ae781774 165 kfree(iface);
ae781774
MW
166}
167#endif
168
1da177e4 169/**
8001c858
DB
170 * ipc_findkey - find a key in an ipc identifier set
171 * @ids: ipc identifier set
172 * @key: key to find
46c0a8ca 173 *
8001c858
DB
174 * Returns the locked pointer to the ipc structure if found or NULL
175 * otherwise. If key is found ipc points to the owning ipc structure
176 *
0cfb6aee 177 * Called with writer ipc_ids.rwsem held.
1da177e4 178 */
7748dbfa 179static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key)
1da177e4 180{
dc2c8c84 181 struct kern_ipc_perm *ipcp;
7ca7e564 182
dc2c8c84 183 ipcp = rhashtable_lookup_fast(&ids->key_ht, &key,
0cfb6aee 184 ipc_kht_params);
dc2c8c84
DB
185 if (!ipcp)
186 return NULL;
7ca7e564 187
dc2c8c84
DB
188 rcu_read_lock();
189 ipc_lock_object(ipcp);
190 return ipcp;
1da177e4
LT
191}
192
b8fd9983 193/*
e2652ae6
MS
194 * Insert new IPC object into idr tree, and set sequence number and id
195 * in the correct order.
196 * Especially:
197 * - the sequence number must be set before inserting the object into the idr,
198 * because the sequence number is accessed without a lock.
199 * - the id can/must be set after inserting the object into the idr.
200 * All accesses must be done after getting kern_ipc_perm.lock.
201 *
202 * The caller must own kern_ipc_perm.lock.of the new object.
203 * On error, the function returns a (negative) error code.
b8fd9983 204 */
e2652ae6 205static inline int ipc_idr_alloc(struct ipc_ids *ids, struct kern_ipc_perm *new)
b8fd9983 206{
e2652ae6
MS
207 int idx, next_id = -1;
208
209#ifdef CONFIG_CHECKPOINT_RESTORE
210 next_id = ids->next_id;
211 ids->next_id = -1;
212#endif
213
214 /*
215 * As soon as a new object is inserted into the idr,
216 * ipc_obtain_object_idr() or ipc_obtain_object_check() can find it,
217 * and the lockless preparations for ipc operations can start.
218 * This means especially: permission checks, audit calls, allocation
219 * of undo structures, ...
220 *
221 * Thus the object must be fully initialized, and if something fails,
222 * then the full tear-down sequence must be followed.
223 * (i.e.: set new->deleted, reduce refcount, call_rcu())
224 */
225
226 if (next_id < 0) { /* !CHECKPOINT_RESTORE or next_id is unset */
b8fd9983
DB
227 new->seq = ids->seq++;
228 if (ids->seq > IPCID_SEQ_MAX)
229 ids->seq = 0;
e2652ae6 230 idx = idr_alloc(&ids->ipcs_idr, new, 0, 0, GFP_NOWAIT);
b8fd9983 231 } else {
e2652ae6
MS
232 new->seq = ipcid_to_seqx(next_id);
233 idx = idr_alloc(&ids->ipcs_idr, new, ipcid_to_idx(next_id),
234 0, GFP_NOWAIT);
b8fd9983 235 }
e2652ae6
MS
236 if (idx >= 0)
237 new->id = SEQ_MULTIPLIER * new->seq + idx;
238 return idx;
b8fd9983
DB
239}
240
1da177e4 241/**
8001c858
DB
242 * ipc_addid - add an ipc identifier
243 * @ids: ipc identifier set
244 * @new: new ipc permission set
ebf66799 245 * @limit: limit for the number of used ids
1da177e4 246 *
8001c858
DB
247 * Add an entry 'new' to the ipc ids idr. The permissions object is
248 * initialised and the first free entry is set up and the id assigned
249 * is returned. The 'new' entry is returned in a locked state on success.
39cfffd7 250 *
8001c858 251 * On failure the entry is not locked and a negative err-code is returned.
39cfffd7 252 * The caller must use ipc_rcu_putref() to free the identifier.
1da177e4 253 *
8001c858 254 * Called with writer ipc_ids.rwsem held.
1da177e4 255 */
ebf66799 256int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int limit)
1da177e4 257{
1efdb69b
EB
258 kuid_t euid;
259 kgid_t egid;
e2652ae6 260 int idx, err;
1da177e4 261
39cfffd7
MS
262 /* 1) Initialize the refcount so that ipc_rcu_putref works */
263 refcount_set(&new->refcount, 1);
264
ebf66799
DB
265 if (limit > IPCMNI)
266 limit = IPCMNI;
7ca7e564 267
dc2c8c84 268 if (ids->in_use >= limit)
283bb7fa 269 return -ENOSPC;
7ca7e564 270
54924ea3
TH
271 idr_preload(GFP_KERNEL);
272
e00b4ff7 273 spin_lock_init(&new->lock);
e00b4ff7
ND
274 rcu_read_lock();
275 spin_lock(&new->lock);
276
b9a53227
LT
277 current_euid_egid(&euid, &egid);
278 new->cuid = new->uid = euid;
279 new->gid = new->cgid = egid;
280
39cfffd7
MS
281 new->deleted = false;
282
e2652ae6 283 idx = ipc_idr_alloc(ids, new);
54924ea3 284 idr_preload_end();
0cfb6aee 285
e2652ae6 286 if (idx >= 0 && new->key != IPC_PRIVATE) {
0cfb6aee
GK
287 err = rhashtable_insert_fast(&ids->key_ht, &new->khtnode,
288 ipc_kht_params);
289 if (err < 0) {
e2652ae6
MS
290 idr_remove(&ids->ipcs_idr, idx);
291 idx = err;
0cfb6aee
GK
292 }
293 }
e2652ae6 294 if (idx < 0) {
39cfffd7 295 new->deleted = true;
e00b4ff7
ND
296 spin_unlock(&new->lock);
297 rcu_read_unlock();
e2652ae6 298 return idx;
e00b4ff7 299 }
7ca7e564 300
1da177e4 301 ids->in_use++;
e2652ae6
MS
302 if (idx > ids->max_id)
303 ids->max_id = idx;
304 return idx;
1da177e4
LT
305}
306
7748dbfa 307/**
8001c858
DB
308 * ipcget_new - create a new ipc object
309 * @ns: ipc namespace
da3dae54 310 * @ids: ipc identifier set
8001c858
DB
311 * @ops: the actual creation routine to call
312 * @params: its parameters
313 *
314 * This routine is called by sys_msgget, sys_semget() and sys_shmget()
315 * when the key is IPC_PRIVATE.
7748dbfa 316 */
b2d75cdd 317static int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids,
eb66ec44 318 const struct ipc_ops *ops, struct ipc_params *params)
7748dbfa
ND
319{
320 int err;
7748dbfa 321
d9a605e4 322 down_write(&ids->rwsem);
7748dbfa 323 err = ops->getnew(ns, params);
d9a605e4 324 up_write(&ids->rwsem);
7748dbfa
ND
325 return err;
326}
327
328/**
8001c858
DB
329 * ipc_check_perms - check security and permissions for an ipc object
330 * @ns: ipc namespace
331 * @ipcp: ipc permission set
332 * @ops: the actual security routine to call
333 * @params: its parameters
f4566f04 334 *
8001c858
DB
335 * This routine is called by sys_msgget(), sys_semget() and sys_shmget()
336 * when the key is not IPC_PRIVATE and that key already exists in the
337 * ds IDR.
f4566f04 338 *
8001c858 339 * On success, the ipc id is returned.
f4566f04 340 *
8001c858 341 * It is called with ipc_ids.rwsem and ipcp->lock held.
7748dbfa 342 */
b0e77598
SH
343static int ipc_check_perms(struct ipc_namespace *ns,
344 struct kern_ipc_perm *ipcp,
eb66ec44 345 const struct ipc_ops *ops,
b0e77598 346 struct ipc_params *params)
7748dbfa
ND
347{
348 int err;
349
b0e77598 350 if (ipcperms(ns, ipcp, params->flg))
7748dbfa
ND
351 err = -EACCES;
352 else {
353 err = ops->associate(ipcp, params->flg);
354 if (!err)
355 err = ipcp->id;
356 }
357
358 return err;
359}
360
361/**
8001c858
DB
362 * ipcget_public - get an ipc object or create a new one
363 * @ns: ipc namespace
da3dae54 364 * @ids: ipc identifier set
8001c858
DB
365 * @ops: the actual creation routine to call
366 * @params: its parameters
367 *
368 * This routine is called by sys_msgget, sys_semget() and sys_shmget()
369 * when the key is not IPC_PRIVATE.
370 * It adds a new entry if the key is not found and does some permission
371 * / security checkings if the key is found.
372 *
373 * On success, the ipc id is returned.
7748dbfa 374 */
b2d75cdd 375static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids,
eb66ec44 376 const struct ipc_ops *ops, struct ipc_params *params)
7748dbfa
ND
377{
378 struct kern_ipc_perm *ipcp;
379 int flg = params->flg;
380 int err;
7748dbfa 381
3e148c79
ND
382 /*
383 * Take the lock as a writer since we are potentially going to add
384 * a new entry + read locks are not "upgradable"
385 */
d9a605e4 386 down_write(&ids->rwsem);
7748dbfa
ND
387 ipcp = ipc_findkey(ids, params->key);
388 if (ipcp == NULL) {
389 /* key not used */
390 if (!(flg & IPC_CREAT))
391 err = -ENOENT;
7748dbfa
ND
392 else
393 err = ops->getnew(ns, params);
394 } else {
395 /* ipc object has been locked by ipc_findkey() */
396
397 if (flg & IPC_CREAT && flg & IPC_EXCL)
398 err = -EEXIST;
399 else {
400 err = 0;
401 if (ops->more_checks)
402 err = ops->more_checks(ipcp, params);
403 if (!err)
f4566f04
ND
404 /*
405 * ipc_check_perms returns the IPC id on
406 * success
407 */
b0e77598 408 err = ipc_check_perms(ns, ipcp, ops, params);
7748dbfa
ND
409 }
410 ipc_unlock(ipcp);
411 }
d9a605e4 412 up_write(&ids->rwsem);
7748dbfa
ND
413
414 return err;
415}
416
0cfb6aee
GK
417/**
418 * ipc_kht_remove - remove an ipc from the key hashtable
419 * @ids: ipc identifier set
420 * @ipcp: ipc perm structure containing the key to remove
421 *
422 * ipc_ids.rwsem (as a writer) and the spinlock for this ID are held
423 * before this function is called, and remain locked on the exit.
424 */
425static void ipc_kht_remove(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
426{
427 if (ipcp->key != IPC_PRIVATE)
428 rhashtable_remove_fast(&ids->key_ht, &ipcp->khtnode,
429 ipc_kht_params);
430}
7748dbfa 431
1da177e4 432/**
8001c858
DB
433 * ipc_rmid - remove an ipc identifier
434 * @ids: ipc identifier set
435 * @ipcp: ipc perm structure containing the identifier to remove
1da177e4 436 *
8001c858
DB
437 * ipc_ids.rwsem (as a writer) and the spinlock for this ID are held
438 * before this function is called, and remain locked on the exit.
1da177e4 439 */
7ca7e564 440void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
1da177e4 441{
ce621f5b 442 int lid = ipcid_to_idx(ipcp->id);
7ca7e564
ND
443
444 idr_remove(&ids->ipcs_idr, lid);
0cfb6aee 445 ipc_kht_remove(ids, ipcp);
1da177e4 446 ids->in_use--;
72a8ff2f 447 ipcp->deleted = true;
15df03c8
DB
448
449 if (unlikely(lid == ids->max_id)) {
450 do {
451 lid--;
452 if (lid == -1)
453 break;
454 } while (!idr_find(&ids->ipcs_idr, lid));
455 ids->max_id = lid;
456 }
1da177e4
LT
457}
458
0cfb6aee
GK
459/**
460 * ipc_set_key_private - switch the key of an existing ipc to IPC_PRIVATE
461 * @ids: ipc identifier set
462 * @ipcp: ipc perm structure containing the key to modify
463 *
464 * ipc_ids.rwsem (as a writer) and the spinlock for this ID are held
465 * before this function is called, and remain locked on the exit.
466 */
467void ipc_set_key_private(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
468{
469 ipc_kht_remove(ids, ipcp);
470 ipcp->key = IPC_PRIVATE;
471}
472
dba4cdd3 473int ipc_rcu_getref(struct kern_ipc_perm *ptr)
1da177e4 474{
9405c03e 475 return refcount_inc_not_zero(&ptr->refcount);
65f27f38
DH
476}
477
dba4cdd3
MS
478void ipc_rcu_putref(struct kern_ipc_perm *ptr,
479 void (*func)(struct rcu_head *head))
1da177e4 480{
9405c03e 481 if (!refcount_dec_and_test(&ptr->refcount))
1da177e4
LT
482 return;
483
dba4cdd3 484 call_rcu(&ptr->rcu, func);
53dad6d3
DB
485}
486
1da177e4 487/**
8001c858
DB
488 * ipcperms - check ipc permissions
489 * @ns: ipc namespace
490 * @ipcp: ipc permission set
491 * @flag: desired permission set
1da177e4 492 *
8001c858
DB
493 * Check user, group, other permissions for access
494 * to ipc resources. return 0 if allowed
b0e77598 495 *
0e056eb5 496 * @flag will most probably be 0 or ``S_...UGO`` from <linux/stat.h>
1da177e4 497 */
b0e77598
SH
498int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flag)
499{
1efdb69b 500 kuid_t euid = current_euid();
a33e6751 501 int requested_mode, granted_mode;
1da177e4 502
a33e6751 503 audit_ipc_obj(ipcp);
1da177e4
LT
504 requested_mode = (flag >> 6) | (flag >> 3) | flag;
505 granted_mode = ipcp->mode;
1efdb69b
EB
506 if (uid_eq(euid, ipcp->cuid) ||
507 uid_eq(euid, ipcp->uid))
1da177e4
LT
508 granted_mode >>= 6;
509 else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid))
510 granted_mode >>= 3;
511 /* is there some bit set in requested_mode but not in granted_mode? */
46c0a8ca 512 if ((requested_mode & ~granted_mode & 0007) &&
b0e77598 513 !ns_capable(ns->user_ns, CAP_IPC_OWNER))
1da177e4
LT
514 return -1;
515
516 return security_ipc_permission(ipcp, flag);
517}
518
519/*
520 * Functions to convert between the kern_ipc_perm structure and the
521 * old/new ipc_perm structures
522 */
523
524/**
8001c858
DB
525 * kernel_to_ipc64_perm - convert kernel ipc permissions to user
526 * @in: kernel permissions
527 * @out: new style ipc permissions
1da177e4 528 *
8001c858
DB
529 * Turn the kernel object @in into a set of permissions descriptions
530 * for returning to userspace (@out).
1da177e4 531 */
239521f3 532void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out)
1da177e4
LT
533{
534 out->key = in->key;
1efdb69b
EB
535 out->uid = from_kuid_munged(current_user_ns(), in->uid);
536 out->gid = from_kgid_munged(current_user_ns(), in->gid);
537 out->cuid = from_kuid_munged(current_user_ns(), in->cuid);
538 out->cgid = from_kgid_munged(current_user_ns(), in->cgid);
1da177e4
LT
539 out->mode = in->mode;
540 out->seq = in->seq;
541}
542
543/**
8001c858
DB
544 * ipc64_perm_to_ipc_perm - convert new ipc permissions to old
545 * @in: new style ipc permissions
546 * @out: old style ipc permissions
1da177e4 547 *
8001c858
DB
548 * Turn the new style permissions object @in into a compatibility
549 * object and store it into the @out pointer.
1da177e4 550 */
239521f3 551void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out)
1da177e4
LT
552{
553 out->key = in->key;
554 SET_UID(out->uid, in->uid);
555 SET_GID(out->gid, in->gid);
556 SET_UID(out->cuid, in->cuid);
557 SET_GID(out->cgid, in->cgid);
558 out->mode = in->mode;
559 out->seq = in->seq;
560}
561
4d2bff5e 562/**
0cfb6aee 563 * ipc_obtain_object_idr
4d2bff5e
DB
564 * @ids: ipc identifier set
565 * @id: ipc id to look for
566 *
567 * Look for an id in the ipc ids idr and return associated ipc object.
568 *
569 * Call inside the RCU critical section.
570 * The ipc object is *not* locked on exit.
571 */
55b7ae50 572struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id)
4d2bff5e
DB
573{
574 struct kern_ipc_perm *out;
575 int lid = ipcid_to_idx(id);
576
577 out = idr_find(&ids->ipcs_idr, lid);
578 if (!out)
579 return ERR_PTR(-EINVAL);
580
581 return out;
582}
583
4d2bff5e
DB
584/**
585 * ipc_obtain_object_check
586 * @ids: ipc identifier set
587 * @id: ipc id to look for
588 *
2e5ceb45
MS
589 * Similar to ipc_obtain_object_idr() but also checks the ipc object
590 * sequence number.
4d2bff5e
DB
591 *
592 * Call inside the RCU critical section.
593 * The ipc object is *not* locked on exit.
594 */
595struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id)
596{
55b7ae50 597 struct kern_ipc_perm *out = ipc_obtain_object_idr(ids, id);
4d2bff5e
DB
598
599 if (IS_ERR(out))
600 goto out;
601
602 if (ipc_checkid(out, id))
6157dbbf 603 return ERR_PTR(-EINVAL);
4d2bff5e 604out:
1da177e4
LT
605 return out;
606}
607
b2d75cdd
PE
608/**
609 * ipcget - Common sys_*get() code
da3dae54 610 * @ns: namespace
8001c858
DB
611 * @ids: ipc identifier set
612 * @ops: operations to be called on ipc object creation, permission checks
613 * and further checks
614 * @params: the parameters needed by the previous operations.
b2d75cdd
PE
615 *
616 * Common routine called by sys_msgget(), sys_semget() and sys_shmget().
617 */
618int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
eb66ec44 619 const struct ipc_ops *ops, struct ipc_params *params)
b2d75cdd
PE
620{
621 if (params->key == IPC_PRIVATE)
622 return ipcget_new(ns, ids, ops, params);
623 else
624 return ipcget_public(ns, ids, ops, params);
625}
626
8f4a3809 627/**
8001c858 628 * ipc_update_perm - update the permissions of an ipc object
8f4a3809
PP
629 * @in: the permission given as input.
630 * @out: the permission of the ipc to set.
631 */
1efdb69b 632int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out)
8f4a3809 633{
1efdb69b
EB
634 kuid_t uid = make_kuid(current_user_ns(), in->uid);
635 kgid_t gid = make_kgid(current_user_ns(), in->gid);
636 if (!uid_valid(uid) || !gid_valid(gid))
637 return -EINVAL;
638
639 out->uid = uid;
640 out->gid = gid;
8f4a3809
PP
641 out->mode = (out->mode & ~S_IRWXUGO)
642 | (in->mode & S_IRWXUGO);
1efdb69b
EB
643
644 return 0;
8f4a3809
PP
645}
646
a5f75e7f 647/**
4241c1a3 648 * ipcctl_obtain_check - retrieve an ipc object and check permissions
8001c858 649 * @ns: ipc namespace
a5f75e7f
PP
650 * @ids: the table of ids where to look for the ipc
651 * @id: the id of the ipc to retrieve
652 * @cmd: the cmd to check
653 * @perm: the permission to set
654 * @extra_perm: one extra permission parameter used by msq
655 *
656 * This function does some common audit and permissions check for some IPC_XXX
657 * cmd and is called from semctl_down, shmctl_down and msgctl_down.
0e056eb5 658 *
4241c1a3
MS
659 * It:
660 * - retrieves the ipc object with the given id in the given table.
0e056eb5 661 * - performs some audit and permission check, depending on the given cmd
662 * - returns a pointer to the ipc object or otherwise, the corresponding
663 * error.
7b4cc5d8 664 *
d9a605e4 665 * Call holding the both the rwsem and the rcu read lock.
a5f75e7f 666 */
4241c1a3 667struct kern_ipc_perm *ipcctl_obtain_check(struct ipc_namespace *ns,
3b1c4ad3
DB
668 struct ipc_ids *ids, int id, int cmd,
669 struct ipc64_perm *perm, int extra_perm)
444d0f62 670{
1efdb69b 671 kuid_t euid;
444d0f62
DB
672 int err = -EPERM;
673 struct kern_ipc_perm *ipcp;
a5f75e7f 674
444d0f62 675 ipcp = ipc_obtain_object_check(ids, id);
a5f75e7f
PP
676 if (IS_ERR(ipcp)) {
677 err = PTR_ERR(ipcp);
7b4cc5d8 678 goto err;
a5f75e7f
PP
679 }
680
a33e6751 681 audit_ipc_obj(ipcp);
e816f370
AV
682 if (cmd == IPC_SET)
683 audit_ipc_set_perm(extra_perm, perm->uid,
444d0f62 684 perm->gid, perm->mode);
414c0708
DH
685
686 euid = current_euid();
1efdb69b 687 if (uid_eq(euid, ipcp->cuid) || uid_eq(euid, ipcp->uid) ||
b0e77598 688 ns_capable(ns->user_ns, CAP_SYS_ADMIN))
7b4cc5d8
DB
689 return ipcp; /* successful lookup */
690err:
a5f75e7f
PP
691 return ERR_PTR(err);
692}
693
c1d7e01d 694#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
1da177e4
LT
695
696
697/**
8001c858
DB
698 * ipc_parse_version - ipc call version
699 * @cmd: pointer to command
1da177e4 700 *
8001c858
DB
701 * Return IPC_64 for new style IPC and IPC_OLD for old style IPC.
702 * The @cmd value is turned from an encoding command and version into
703 * just the command code.
1da177e4 704 */
239521f3 705int ipc_parse_version(int *cmd)
1da177e4
LT
706{
707 if (*cmd & IPC_64) {
708 *cmd ^= IPC_64;
709 return IPC_64;
710 } else {
711 return IPC_OLD;
712 }
713}
714
c1d7e01d 715#endif /* CONFIG_ARCH_WANT_IPC_PARSE_VERSION */
ae781774
MW
716
717#ifdef CONFIG_PROC_FS
bc1fc6d8
EB
718struct ipc_proc_iter {
719 struct ipc_namespace *ns;
03f1fc09 720 struct pid_namespace *pid_ns;
bc1fc6d8
EB
721 struct ipc_proc_iface *iface;
722};
723
03f1fc09
EB
724struct pid_namespace *ipc_seq_pid_ns(struct seq_file *s)
725{
726 struct ipc_proc_iter *iter = s->private;
727 return iter->pid_ns;
728}
729
7ca7e564
ND
730/*
731 * This routine locks the ipc structure found at least at position pos.
732 */
b524b9ad
AB
733static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos,
734 loff_t *new_pos)
ae781774 735{
7ca7e564
ND
736 struct kern_ipc_perm *ipc;
737 int total, id;
73ea4130 738
7ca7e564
ND
739 total = 0;
740 for (id = 0; id < pos && total < ids->in_use; id++) {
741 ipc = idr_find(&ids->ipcs_idr, id);
742 if (ipc != NULL)
743 total++;
744 }
ae781774 745
7ca7e564
ND
746 if (total >= ids->in_use)
747 return NULL;
ae781774 748
239521f3 749 for (; pos < IPCMNI; pos++) {
7ca7e564
ND
750 ipc = idr_find(&ids->ipcs_idr, pos);
751 if (ipc != NULL) {
752 *new_pos = pos + 1;
32a27500
DB
753 rcu_read_lock();
754 ipc_lock_object(ipc);
ae781774
MW
755 return ipc;
756 }
757 }
758
759 /* Out of range - return NULL to terminate iteration */
760 return NULL;
761}
762
7ca7e564
ND
763static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos)
764{
765 struct ipc_proc_iter *iter = s->private;
766 struct ipc_proc_iface *iface = iter->iface;
767 struct kern_ipc_perm *ipc = it;
768
769 /* If we had an ipc id locked before, unlock it */
770 if (ipc && ipc != SEQ_START_TOKEN)
771 ipc_unlock(ipc);
772
ed2ddbf8 773 return sysvipc_find_ipc(&iter->ns->ids[iface->ids], *pos, pos);
7ca7e564
ND
774}
775
ae781774 776/*
f4566f04
ND
777 * File positions: pos 0 -> header, pos n -> ipc id = n - 1.
778 * SeqFile iterator: iterator value locked ipc pointer or SEQ_TOKEN_START.
ae781774
MW
779 */
780static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos)
781{
bc1fc6d8
EB
782 struct ipc_proc_iter *iter = s->private;
783 struct ipc_proc_iface *iface = iter->iface;
73ea4130
KK
784 struct ipc_ids *ids;
785
ed2ddbf8 786 ids = &iter->ns->ids[iface->ids];
ae781774
MW
787
788 /*
789 * Take the lock - this will be released by the corresponding
790 * call to stop().
791 */
d9a605e4 792 down_read(&ids->rwsem);
ae781774
MW
793
794 /* pos < 0 is invalid */
795 if (*pos < 0)
796 return NULL;
797
798 /* pos == 0 means header */
799 if (*pos == 0)
800 return SEQ_START_TOKEN;
801
802 /* Find the (pos-1)th ipc */
7ca7e564 803 return sysvipc_find_ipc(ids, *pos - 1, pos);
ae781774
MW
804}
805
806static void sysvipc_proc_stop(struct seq_file *s, void *it)
807{
808 struct kern_ipc_perm *ipc = it;
bc1fc6d8
EB
809 struct ipc_proc_iter *iter = s->private;
810 struct ipc_proc_iface *iface = iter->iface;
73ea4130 811 struct ipc_ids *ids;
ae781774 812
f4566f04 813 /* If we had a locked structure, release it */
ae781774
MW
814 if (ipc && ipc != SEQ_START_TOKEN)
815 ipc_unlock(ipc);
816
ed2ddbf8 817 ids = &iter->ns->ids[iface->ids];
ae781774 818 /* Release the lock we took in start() */
d9a605e4 819 up_read(&ids->rwsem);
ae781774
MW
820}
821
822static int sysvipc_proc_show(struct seq_file *s, void *it)
823{
bc1fc6d8
EB
824 struct ipc_proc_iter *iter = s->private;
825 struct ipc_proc_iface *iface = iter->iface;
ae781774 826
7f032d6e
JP
827 if (it == SEQ_START_TOKEN) {
828 seq_puts(s, iface->header);
829 return 0;
830 }
ae781774
MW
831
832 return iface->show(s, it);
833}
834
88e9d34c 835static const struct seq_operations sysvipc_proc_seqops = {
ae781774
MW
836 .start = sysvipc_proc_start,
837 .stop = sysvipc_proc_stop,
838 .next = sysvipc_proc_next,
839 .show = sysvipc_proc_show,
840};
841
bc1fc6d8
EB
842static int sysvipc_proc_open(struct inode *inode, struct file *file)
843{
bc1fc6d8
EB
844 struct ipc_proc_iter *iter;
845
d66a0520 846 iter = __seq_open_private(file, &sysvipc_proc_seqops, sizeof(*iter));
bc1fc6d8 847 if (!iter)
d66a0520 848 return -ENOMEM;
bc1fc6d8 849
d9dda78b 850 iter->iface = PDE_DATA(inode);
bc1fc6d8 851 iter->ns = get_ipc_ns(current->nsproxy->ipc_ns);
03f1fc09 852 iter->pid_ns = get_pid_ns(task_active_pid_ns(current));
d66a0520
RJ
853
854 return 0;
bc1fc6d8
EB
855}
856
857static int sysvipc_proc_release(struct inode *inode, struct file *file)
858{
859 struct seq_file *seq = file->private_data;
860 struct ipc_proc_iter *iter = seq->private;
861 put_ipc_ns(iter->ns);
03f1fc09 862 put_pid_ns(iter->pid_ns);
bc1fc6d8 863 return seq_release_private(inode, file);
ae781774
MW
864}
865
9a32144e 866static const struct file_operations sysvipc_proc_fops = {
ae781774
MW
867 .open = sysvipc_proc_open,
868 .read = seq_read,
869 .llseek = seq_lseek,
bc1fc6d8 870 .release = sysvipc_proc_release,
ae781774
MW
871};
872#endif /* CONFIG_PROC_FS */