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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
Christian Kujau624dffc2006-01-15 02:43:54 +010010 * Manfred Spraul <manfred@colorfullife.com>
Linus Torvalds1da177e2005-04-16 15:20:36 -070011 * Oct 2002 - One lock per IPC id. RCU ipc_free for lock-free grow_ary().
12 * Mingming Cao <cmm@us.ibm.com>
Steve Grubb073115d2006-04-02 17:07:33 -040013 * Mar 2006 - support for audit of ipc object properties
14 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
Kirill Korotaev73ea4132006-10-02 02:18:20 -070015 * Jun 2006 - namespaces ssupport
16 * OpenVZ, SWsoft Inc.
17 * Pavel Emelianov <xemul@openvz.org>
Davidlohr Bueso05603c42013-09-11 14:26:26 -070018 *
19 * General sysv ipc locking scheme:
Davidlohr Bueso18ccee22013-10-16 13:46:45 -070020 * 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().
Linus Torvalds1da177e2005-04-16 15:20:36 -070041 */
42
Linus Torvalds1da177e2005-04-16 15:20:36 -070043#include <linux/mm.h>
44#include <linux/shm.h>
45#include <linux/init.h>
46#include <linux/msg.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070047#include <linux/vmalloc.h>
48#include <linux/slab.h>
Andrew Morton8f68fa22013-04-29 15:08:05 -070049#include <linux/notifier.h>
Randy.Dunlapc59ede72006-01-11 12:17:46 -080050#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070051#include <linux/highuid.h>
52#include <linux/security.h>
53#include <linux/rcupdate.h>
54#include <linux/workqueue.h>
Mike Waychisonae781772005-09-06 15:17:09 -070055#include <linux/seq_file.h>
56#include <linux/proc_fs.h>
Steve Grubb073115d2006-04-02 17:07:33 -040057#include <linux/audit.h>
Kirill Korotaev73ea4132006-10-02 02:18:20 -070058#include <linux/nsproxy.h>
Nadia Derbey3e148c72007-10-18 23:40:54 -070059#include <linux/rwsem.h>
Nadia Derbeyb6b337a2008-04-29 01:00:42 -070060#include <linux/memory.h>
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -080061#include <linux/ipc_namespace.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070062
63#include <asm/unistd.h>
64
65#include "util.h"
66
Mike Waychisonae781772005-09-06 15:17:09 -070067struct ipc_proc_iface {
68 const char *path;
69 const char *header;
Kirill Korotaev73ea4132006-10-02 02:18:20 -070070 int ids;
Mike Waychisonae781772005-09-06 15:17:09 -070071 int (*show)(struct seq_file *, void *);
72};
73
Linus Torvalds1da177e2005-04-16 15:20:36 -070074/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -080075 * ipc_init - initialise ipc subsystem
Linus Torvalds1da177e2005-04-16 15:20:36 -070076 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -080077 * The various sysv ipc resources (semaphores, messages and shared
78 * memory) are initialised.
79 *
80 * A callback routine is registered into the memory hotplug notifier
81 * chain: since msgmni scales to lowmem this callback routine will be
82 * called upon successful memory add / remove to recompute msmgni.
Linus Torvalds1da177e2005-04-16 15:20:36 -070083 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070084static int __init ipc_init(void)
85{
86 sem_init();
87 msg_init();
88 shm_init();
89 return 0;
90}
Davidlohr Bueso6d08a252014-04-07 15:39:18 -070091device_initcall(ipc_init);
Linus Torvalds1da177e2005-04-16 15:20:36 -070092
93/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -080094 * ipc_init_ids - initialise ipc identifiers
95 * @ids: ipc identifier set
Linus Torvalds1da177e2005-04-16 15:20:36 -070096 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -080097 * Set up the sequence range to use for the ipc identifier range (limited
98 * below IPCMNI) then initialise the ids idr.
Linus Torvalds1da177e2005-04-16 15:20:36 -070099 */
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700100void ipc_init_ids(struct ipc_ids *ids)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102 ids->in_use = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103 ids->seq = 0;
Stanislav Kinsbursky03f59562013-01-04 15:34:50 -0800104 ids->next_id = -1;
Davidlohr Buesodaf948c2014-01-27 17:07:09 -0800105 init_rwsem(&ids->rwsem);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700106 idr_init(&ids->ipcs_idr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107}
108
Mike Waychisonae781772005-09-06 15:17:09 -0700109#ifdef CONFIG_PROC_FS
Arjan van de Ven9a321442007-02-12 00:55:35 -0800110static const struct file_operations sysvipc_proc_fops;
Mike Waychisonae781772005-09-06 15:17:09 -0700111/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800112 * ipc_init_proc_interface - create a proc interface for sysipc types using a seq_file interface.
113 * @path: Path in procfs
114 * @header: Banner to be printed at the beginning of the file.
115 * @ids: ipc id table to iterate.
116 * @show: show routine.
Mike Waychisonae781772005-09-06 15:17:09 -0700117 */
118void __init ipc_init_proc_interface(const char *path, const char *header,
Kirill Korotaev73ea4132006-10-02 02:18:20 -0700119 int ids, int (*show)(struct seq_file *, void *))
Mike Waychisonae781772005-09-06 15:17:09 -0700120{
121 struct proc_dir_entry *pde;
122 struct ipc_proc_iface *iface;
123
124 iface = kmalloc(sizeof(*iface), GFP_KERNEL);
125 if (!iface)
126 return;
127 iface->path = path;
128 iface->header = header;
129 iface->ids = ids;
130 iface->show = show;
131
Denis V. Lunev6a6375d2008-04-29 01:02:12 -0700132 pde = proc_create_data(path,
133 S_IRUGO, /* world readable */
134 NULL, /* parent dir */
135 &sysvipc_proc_fops,
136 iface);
Davidlohr Bueso3ab08fe2014-01-27 17:07:06 -0800137 if (!pde)
Mike Waychisonae781772005-09-06 15:17:09 -0700138 kfree(iface);
Mike Waychisonae781772005-09-06 15:17:09 -0700139}
140#endif
141
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800143 * ipc_findkey - find a key in an ipc identifier set
144 * @ids: ipc identifier set
145 * @key: key to find
Paul McQuade46c0a8c2014-06-06 14:37:37 -0700146 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800147 * Returns the locked pointer to the ipc structure if found or NULL
148 * otherwise. If key is found ipc points to the owning ipc structure
149 *
150 * Called with ipc_ids.rwsem held.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151 */
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700152static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153{
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700154 struct kern_ipc_perm *ipc;
155 int next_id;
156 int total;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700158 for (total = 0, next_id = 0; total < ids->in_use; next_id++) {
159 ipc = idr_find(&ids->ipcs_idr, next_id);
160
161 if (ipc == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162 continue;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700163
164 if (ipc->key != key) {
165 total++;
166 continue;
167 }
168
Davidlohr Bueso32a27502013-09-11 14:26:29 -0700169 rcu_read_lock();
170 ipc_lock_object(ipc);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700171 return ipc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 }
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700173
174 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175}
176
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700177/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800178 * ipc_get_maxid - get the last assigned id
179 * @ids: ipc identifier set
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700180 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800181 * Called with ipc_ids.rwsem held.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 */
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700183int ipc_get_maxid(struct ipc_ids *ids)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184{
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700185 struct kern_ipc_perm *ipc;
186 int max_id = -1;
187 int total, id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700189 if (ids->in_use == 0)
190 return -1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700192 if (ids->in_use == IPCMNI)
193 return IPCMNI - 1;
194
195 /* Look for the last assigned id */
196 total = 0;
197 for (id = 0; id < IPCMNI && total < ids->in_use; id++) {
198 ipc = idr_find(&ids->ipcs_idr, id);
199 if (ipc != NULL) {
200 max_id = id;
201 total++;
202 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 }
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700204 return max_id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205}
206
207/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800208 * ipc_addid - add an ipc identifier
209 * @ids: ipc identifier set
210 * @new: new ipc permission set
211 * @size: limit for the number of used ids
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800213 * Add an entry 'new' to the ipc ids idr. The permissions object is
214 * initialised and the first free entry is set up and the id assigned
215 * is returned. The 'new' entry is returned in a locked state on success.
216 * On failure the entry is not locked and a negative err-code is returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800218 * Called with writer ipc_ids.rwsem held.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219 */
Manfred Spraul239521f2014-01-27 17:07:04 -0800220int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700221{
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800222 kuid_t euid;
223 kgid_t egid;
Tejun Heo54924ea2013-02-27 17:04:53 -0800224 int id;
Stanislav Kinsbursky03f59562013-01-04 15:34:50 -0800225 int next_id = ids->next_id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700227 if (size > IPCMNI)
228 size = IPCMNI;
229
230 if (ids->in_use >= size)
Pierre Peiffer283bb7f2007-10-18 23:40:57 -0700231 return -ENOSPC;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700232
Tejun Heo54924ea2013-02-27 17:04:53 -0800233 idr_preload(GFP_KERNEL);
234
Nadia Derbeye00b4ff7e2008-11-19 15:36:08 -0800235 spin_lock_init(&new->lock);
Rafael Aquini72a8ff22014-01-27 17:07:02 -0800236 new->deleted = false;
Nadia Derbeye00b4ff7e2008-11-19 15:36:08 -0800237 rcu_read_lock();
238 spin_lock(&new->lock);
239
Tejun Heo54924ea2013-02-27 17:04:53 -0800240 id = idr_alloc(&ids->ipcs_idr, new,
241 (next_id < 0) ? 0 : ipcid_to_idx(next_id), 0,
242 GFP_NOWAIT);
243 idr_preload_end();
244 if (id < 0) {
Nadia Derbeye00b4ff7e2008-11-19 15:36:08 -0800245 spin_unlock(&new->lock);
246 rcu_read_unlock();
Tejun Heo54924ea2013-02-27 17:04:53 -0800247 return id;
Nadia Derbeye00b4ff7e2008-11-19 15:36:08 -0800248 }
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700249
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250 ids->in_use++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251
David Howells414c0702008-11-14 10:39:06 +1100252 current_euid_egid(&euid, &egid);
253 new->cuid = new->uid = euid;
254 new->gid = new->cgid = egid;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255
Stanislav Kinsbursky03f59562013-01-04 15:34:50 -0800256 if (next_id < 0) {
257 new->seq = ids->seq++;
Davidlohr Buesodaf948c2014-01-27 17:07:09 -0800258 if (ids->seq > IPCID_SEQ_MAX)
Stanislav Kinsbursky03f59562013-01-04 15:34:50 -0800259 ids->seq = 0;
260 } else {
261 new->seq = ipcid_to_seqx(next_id);
262 ids->next_id = -1;
263 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264
Pierre Peiffer48dea402008-04-29 01:00:35 -0700265 new->id = ipc_buildid(id, new->seq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266 return id;
267}
268
269/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800270 * ipcget_new - create a new ipc object
271 * @ns: ipc namespace
Masanari Iidada3dae52014-09-09 01:27:23 +0900272 * @ids: ipc identifier set
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800273 * @ops: the actual creation routine to call
274 * @params: its parameters
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700275 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800276 * This routine is called by sys_msgget, sys_semget() and sys_shmget()
277 * when the key is IPC_PRIVATE.
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700278 */
Pavel Emelyanovb2d75cd2008-02-08 04:18:54 -0800279static int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids,
Mathias Krauseeb66ec42014-06-06 14:37:36 -0700280 const struct ipc_ops *ops, struct ipc_params *params)
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700281{
282 int err;
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700283
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700284 down_write(&ids->rwsem);
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700285 err = ops->getnew(ns, params);
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700286 up_write(&ids->rwsem);
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700287 return err;
288}
289
290/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800291 * ipc_check_perms - check security and permissions for an ipc object
292 * @ns: ipc namespace
293 * @ipcp: ipc permission set
294 * @ops: the actual security routine to call
295 * @params: its parameters
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700296 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800297 * This routine is called by sys_msgget(), sys_semget() and sys_shmget()
298 * when the key is not IPC_PRIVATE and that key already exists in the
299 * ds IDR.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700300 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800301 * On success, the ipc id is returned.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700302 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800303 * It is called with ipc_ids.rwsem and ipcp->lock held.
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700304 */
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700305static int ipc_check_perms(struct ipc_namespace *ns,
306 struct kern_ipc_perm *ipcp,
Mathias Krauseeb66ec42014-06-06 14:37:36 -0700307 const struct ipc_ops *ops,
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700308 struct ipc_params *params)
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700309{
310 int err;
311
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700312 if (ipcperms(ns, ipcp, params->flg))
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700313 err = -EACCES;
314 else {
315 err = ops->associate(ipcp, params->flg);
316 if (!err)
317 err = ipcp->id;
318 }
319
320 return err;
321}
322
323/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800324 * ipcget_public - get an ipc object or create a new one
325 * @ns: ipc namespace
Masanari Iidada3dae52014-09-09 01:27:23 +0900326 * @ids: ipc identifier set
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800327 * @ops: the actual creation routine to call
328 * @params: its parameters
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700329 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800330 * This routine is called by sys_msgget, sys_semget() and sys_shmget()
331 * when the key is not IPC_PRIVATE.
332 * It adds a new entry if the key is not found and does some permission
333 * / security checkings if the key is found.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700334 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800335 * On success, the ipc id is returned.
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700336 */
Pavel Emelyanovb2d75cd2008-02-08 04:18:54 -0800337static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids,
Mathias Krauseeb66ec42014-06-06 14:37:36 -0700338 const struct ipc_ops *ops, struct ipc_params *params)
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700339{
340 struct kern_ipc_perm *ipcp;
341 int flg = params->flg;
342 int err;
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700343
Nadia Derbey3e148c72007-10-18 23:40:54 -0700344 /*
345 * Take the lock as a writer since we are potentially going to add
346 * a new entry + read locks are not "upgradable"
347 */
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700348 down_write(&ids->rwsem);
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700349 ipcp = ipc_findkey(ids, params->key);
350 if (ipcp == NULL) {
351 /* key not used */
352 if (!(flg & IPC_CREAT))
353 err = -ENOENT;
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700354 else
355 err = ops->getnew(ns, params);
356 } else {
357 /* ipc object has been locked by ipc_findkey() */
358
359 if (flg & IPC_CREAT && flg & IPC_EXCL)
360 err = -EEXIST;
361 else {
362 err = 0;
363 if (ops->more_checks)
364 err = ops->more_checks(ipcp, params);
365 if (!err)
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700366 /*
367 * ipc_check_perms returns the IPC id on
368 * success
369 */
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700370 err = ipc_check_perms(ns, ipcp, ops, params);
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700371 }
372 ipc_unlock(ipcp);
373 }
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700374 up_write(&ids->rwsem);
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700375
376 return err;
377}
378
379
380/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800381 * ipc_rmid - remove an ipc identifier
382 * @ids: ipc identifier set
383 * @ipcp: ipc perm structure containing the identifier to remove
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800385 * ipc_ids.rwsem (as a writer) and the spinlock for this ID are held
386 * before this function is called, and remain locked on the exit.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387 */
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700388void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389{
Nadia Derbeyce621f52007-10-18 23:40:52 -0700390 int lid = ipcid_to_idx(ipcp->id);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700391
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700392 idr_remove(&ids->ipcs_idr, lid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700393 ids->in_use--;
Rafael Aquini72a8ff22014-01-27 17:07:02 -0800394 ipcp->deleted = true;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395}
396
397/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800398 * ipc_alloc - allocate ipc space
399 * @size: size desired
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800401 * Allocate memory from the appropriate pools and return a pointer to it.
402 * NULL is returned if the allocation fails
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403 */
Rik van Riel6062a8d2013-04-30 19:15:44 -0700404void *ipc_alloc(int size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405{
Rik van Riel6062a8d2013-04-30 19:15:44 -0700406 void *out;
Manfred Spraul239521f2014-01-27 17:07:04 -0800407 if (size > PAGE_SIZE)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408 out = vmalloc(size);
409 else
410 out = kmalloc(size, GFP_KERNEL);
411 return out;
412}
413
414/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800415 * ipc_free - free ipc space
416 * @ptr: pointer returned by ipc_alloc
417 * @size: size of block
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800419 * Free a block created with ipc_alloc(). The caller must know the size
420 * used in the allocation call.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421 */
Manfred Spraul239521f2014-01-27 17:07:04 -0800422void ipc_free(void *ptr, int size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423{
Manfred Spraul239521f2014-01-27 17:07:04 -0800424 if (size > PAGE_SIZE)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425 vfree(ptr);
426 else
427 kfree(ptr);
428}
429
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800431 * ipc_rcu_alloc - allocate ipc and rcu space
432 * @size: size desired
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800434 * Allocate memory for the rcu header structure + the object.
435 * Returns the pointer to the object or NULL upon failure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436 */
Rik van Riel6062a8d2013-04-30 19:15:44 -0700437void *ipc_rcu_alloc(int size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438{
Rik van Riel6062a8d2013-04-30 19:15:44 -0700439 /*
Al Viro600fe972013-04-29 12:42:09 -0400440 * We prepend the allocation with the rcu struct
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441 */
Al Viro600fe972013-04-29 12:42:09 -0400442 struct ipc_rcu *out = ipc_alloc(sizeof(struct ipc_rcu) + size);
443 if (unlikely(!out))
444 return NULL;
445 atomic_set(&out->refcount, 1);
Manfred Spraul196aa012013-07-08 16:01:20 -0700446 return out + 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447}
448
Rik van Riel6062a8d2013-04-30 19:15:44 -0700449int ipc_rcu_getref(void *ptr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450{
Manfred Spraul196aa012013-07-08 16:01:20 -0700451 struct ipc_rcu *p = ((struct ipc_rcu *)ptr) - 1;
452
453 return atomic_inc_not_zero(&p->refcount);
David Howells65f27f32006-11-22 14:55:48 +0000454}
455
Davidlohr Bueso53dad6d2013-09-23 17:04:45 -0700456void ipc_rcu_putref(void *ptr, void (*func)(struct rcu_head *head))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700457{
Manfred Spraul196aa012013-07-08 16:01:20 -0700458 struct ipc_rcu *p = ((struct ipc_rcu *)ptr) - 1;
Al Viro600fe972013-04-29 12:42:09 -0400459
460 if (!atomic_dec_and_test(&p->refcount))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461 return;
462
Davidlohr Bueso53dad6d2013-09-23 17:04:45 -0700463 call_rcu(&p->rcu, func);
464}
465
466void ipc_rcu_free(struct rcu_head *head)
467{
468 struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu);
469
Pekka Enbergc859aa82015-06-30 14:58:33 -0700470 kvfree(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471}
472
473/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800474 * ipcperms - check ipc permissions
475 * @ns: ipc namespace
476 * @ipcp: ipc permission set
477 * @flag: desired permission set
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800479 * Check user, group, other permissions for access
480 * to ipc resources. return 0 if allowed
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700481 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800482 * @flag will most probably be 0 or S_...UGO from <linux/stat.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483 */
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700484int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flag)
485{
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800486 kuid_t euid = current_euid();
Al Viroa33e6752008-12-10 03:40:06 -0500487 int requested_mode, granted_mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488
Al Viroa33e6752008-12-10 03:40:06 -0500489 audit_ipc_obj(ipcp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490 requested_mode = (flag >> 6) | (flag >> 3) | flag;
491 granted_mode = ipcp->mode;
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800492 if (uid_eq(euid, ipcp->cuid) ||
493 uid_eq(euid, ipcp->uid))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700494 granted_mode >>= 6;
495 else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid))
496 granted_mode >>= 3;
497 /* is there some bit set in requested_mode but not in granted_mode? */
Paul McQuade46c0a8c2014-06-06 14:37:37 -0700498 if ((requested_mode & ~granted_mode & 0007) &&
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700499 !ns_capable(ns->user_ns, CAP_IPC_OWNER))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500 return -1;
501
502 return security_ipc_permission(ipcp, flag);
503}
504
505/*
506 * Functions to convert between the kern_ipc_perm structure and the
507 * old/new ipc_perm structures
508 */
509
510/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800511 * kernel_to_ipc64_perm - convert kernel ipc permissions to user
512 * @in: kernel permissions
513 * @out: new style ipc permissions
Linus Torvalds1da177e2005-04-16 15:20:36 -0700514 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800515 * Turn the kernel object @in into a set of permissions descriptions
516 * for returning to userspace (@out).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517 */
Manfred Spraul239521f2014-01-27 17:07:04 -0800518void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519{
520 out->key = in->key;
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800521 out->uid = from_kuid_munged(current_user_ns(), in->uid);
522 out->gid = from_kgid_munged(current_user_ns(), in->gid);
523 out->cuid = from_kuid_munged(current_user_ns(), in->cuid);
524 out->cgid = from_kgid_munged(current_user_ns(), in->cgid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525 out->mode = in->mode;
526 out->seq = in->seq;
527}
528
529/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800530 * ipc64_perm_to_ipc_perm - convert new ipc permissions to old
531 * @in: new style ipc permissions
532 * @out: old style ipc permissions
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800534 * Turn the new style permissions object @in into a compatibility
535 * object and store it into the @out pointer.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536 */
Manfred Spraul239521f2014-01-27 17:07:04 -0800537void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700538{
539 out->key = in->key;
540 SET_UID(out->uid, in->uid);
541 SET_GID(out->gid, in->gid);
542 SET_UID(out->cuid, in->cuid);
543 SET_GID(out->cgid, in->cgid);
544 out->mode = in->mode;
545 out->seq = in->seq;
546}
547
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700548/**
Davidlohr Bueso4d2bff52013-04-30 19:15:19 -0700549 * ipc_obtain_object
550 * @ids: ipc identifier set
551 * @id: ipc id to look for
552 *
553 * Look for an id in the ipc ids idr and return associated ipc object.
554 *
555 * Call inside the RCU critical section.
556 * The ipc object is *not* locked on exit.
557 */
Davidlohr Bueso55b7ae52015-06-30 14:58:42 -0700558struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id)
Davidlohr Bueso4d2bff52013-04-30 19:15:19 -0700559{
560 struct kern_ipc_perm *out;
561 int lid = ipcid_to_idx(id);
562
563 out = idr_find(&ids->ipcs_idr, lid);
564 if (!out)
565 return ERR_PTR(-EINVAL);
566
567 return out;
568}
569
570/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800571 * ipc_lock - lock an ipc structure without rwsem held
572 * @ids: ipc identifier set
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700573 * @id: ipc id to look for
574 *
575 * Look for an id in the ipc ids idr and lock the associated ipc object.
576 *
Davidlohr Bueso4d2bff52013-04-30 19:15:19 -0700577 * The ipc object is locked on successful exit.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700578 */
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700579struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700580{
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700581 struct kern_ipc_perm *out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700582
583 rcu_read_lock();
Davidlohr Bueso55b7ae52015-06-30 14:58:42 -0700584 out = ipc_obtain_object_idr(ids, id);
Davidlohr Bueso4d2bff52013-04-30 19:15:19 -0700585 if (IS_ERR(out))
Davidlohr Buesof8b59182015-06-30 14:58:45 -0700586 goto err;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700587
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588 spin_lock(&out->lock);
Davidlohr Bueso4d2bff52013-04-30 19:15:19 -0700589
Davidlohr Buesof8b59182015-06-30 14:58:45 -0700590 /*
591 * ipc_rmid() may have already freed the ID while ipc_lock()
592 * was spinning: here verify that the structure is still valid.
593 * Upon races with RMID, return -EIDRM, thus indicating that
594 * the ID points to a removed identifier.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595 */
Rafael Aquini72a8ff22014-01-27 17:07:02 -0800596 if (ipc_valid_object(out))
Davidlohr Bueso4d2bff52013-04-30 19:15:19 -0700597 return out;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700598
Davidlohr Bueso4d2bff52013-04-30 19:15:19 -0700599 spin_unlock(&out->lock);
Davidlohr Buesof8b59182015-06-30 14:58:45 -0700600 out = ERR_PTR(-EIDRM);
601err:
Davidlohr Bueso4d2bff52013-04-30 19:15:19 -0700602 rcu_read_unlock();
603 return out;
604}
605
606/**
607 * ipc_obtain_object_check
608 * @ids: ipc identifier set
609 * @id: ipc id to look for
610 *
Davidlohr Bueso55b7ae52015-06-30 14:58:42 -0700611 * Similar to ipc_obtain_object_idr() but also checks
Davidlohr Bueso4d2bff52013-04-30 19:15:19 -0700612 * the ipc object reference counter.
613 *
614 * Call inside the RCU critical section.
615 * The ipc object is *not* locked on exit.
616 */
617struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id)
618{
Davidlohr Bueso55b7ae52015-06-30 14:58:42 -0700619 struct kern_ipc_perm *out = ipc_obtain_object_idr(ids, id);
Davidlohr Bueso4d2bff52013-04-30 19:15:19 -0700620
621 if (IS_ERR(out))
622 goto out;
623
624 if (ipc_checkid(out, id))
Davidlohr Bueso6157dbb2015-06-30 14:58:48 -0700625 return ERR_PTR(-EINVAL);
Davidlohr Bueso4d2bff52013-04-30 19:15:19 -0700626out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700627 return out;
628}
629
Pavel Emelyanovb2d75cd2008-02-08 04:18:54 -0800630/**
631 * ipcget - Common sys_*get() code
Masanari Iidada3dae52014-09-09 01:27:23 +0900632 * @ns: namespace
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800633 * @ids: ipc identifier set
634 * @ops: operations to be called on ipc object creation, permission checks
635 * and further checks
636 * @params: the parameters needed by the previous operations.
Pavel Emelyanovb2d75cd2008-02-08 04:18:54 -0800637 *
638 * Common routine called by sys_msgget(), sys_semget() and sys_shmget().
639 */
640int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
Mathias Krauseeb66ec42014-06-06 14:37:36 -0700641 const struct ipc_ops *ops, struct ipc_params *params)
Pavel Emelyanovb2d75cd2008-02-08 04:18:54 -0800642{
643 if (params->key == IPC_PRIVATE)
644 return ipcget_new(ns, ids, ops, params);
645 else
646 return ipcget_public(ns, ids, ops, params);
647}
648
Pierre Peiffer8f4a3802008-04-29 01:00:51 -0700649/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800650 * ipc_update_perm - update the permissions of an ipc object
Pierre Peiffer8f4a3802008-04-29 01:00:51 -0700651 * @in: the permission given as input.
652 * @out: the permission of the ipc to set.
653 */
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800654int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out)
Pierre Peiffer8f4a3802008-04-29 01:00:51 -0700655{
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800656 kuid_t uid = make_kuid(current_user_ns(), in->uid);
657 kgid_t gid = make_kgid(current_user_ns(), in->gid);
658 if (!uid_valid(uid) || !gid_valid(gid))
659 return -EINVAL;
660
661 out->uid = uid;
662 out->gid = gid;
Pierre Peiffer8f4a3802008-04-29 01:00:51 -0700663 out->mode = (out->mode & ~S_IRWXUGO)
664 | (in->mode & S_IRWXUGO);
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800665
666 return 0;
Pierre Peiffer8f4a3802008-04-29 01:00:51 -0700667}
668
Pierre Peiffera5f75e72008-04-29 01:00:54 -0700669/**
Davidlohr Bueso3b1c4ad2013-09-11 14:26:17 -0700670 * ipcctl_pre_down_nolock - retrieve an ipc and check permissions for some IPC_XXX cmd
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800671 * @ns: ipc namespace
Pierre Peiffera5f75e72008-04-29 01:00:54 -0700672 * @ids: the table of ids where to look for the ipc
673 * @id: the id of the ipc to retrieve
674 * @cmd: the cmd to check
675 * @perm: the permission to set
676 * @extra_perm: one extra permission parameter used by msq
677 *
678 * This function does some common audit and permissions check for some IPC_XXX
679 * cmd and is called from semctl_down, shmctl_down and msgctl_down.
680 * It must be called without any lock held and
681 * - retrieves the ipc with the given id in the given table.
682 * - performs some audit and permission check, depending on the given cmd
Davidlohr Bueso3b1c4ad2013-09-11 14:26:17 -0700683 * - returns a pointer to the ipc object or otherwise, the corresponding error.
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -0700684 *
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700685 * Call holding the both the rwsem and the rcu read lock.
Pierre Peiffera5f75e72008-04-29 01:00:54 -0700686 */
Davidlohr Bueso444d0f62013-04-30 19:15:24 -0700687struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns,
Davidlohr Bueso3b1c4ad2013-09-11 14:26:17 -0700688 struct ipc_ids *ids, int id, int cmd,
689 struct ipc64_perm *perm, int extra_perm)
Davidlohr Bueso444d0f62013-04-30 19:15:24 -0700690{
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800691 kuid_t euid;
Davidlohr Bueso444d0f62013-04-30 19:15:24 -0700692 int err = -EPERM;
693 struct kern_ipc_perm *ipcp;
Pierre Peiffera5f75e72008-04-29 01:00:54 -0700694
Davidlohr Bueso444d0f62013-04-30 19:15:24 -0700695 ipcp = ipc_obtain_object_check(ids, id);
Pierre Peiffera5f75e72008-04-29 01:00:54 -0700696 if (IS_ERR(ipcp)) {
697 err = PTR_ERR(ipcp);
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -0700698 goto err;
Pierre Peiffera5f75e72008-04-29 01:00:54 -0700699 }
700
Al Viroa33e6752008-12-10 03:40:06 -0500701 audit_ipc_obj(ipcp);
Al Viroe816f372008-12-10 03:47:15 -0500702 if (cmd == IPC_SET)
703 audit_ipc_set_perm(extra_perm, perm->uid,
Davidlohr Bueso444d0f62013-04-30 19:15:24 -0700704 perm->gid, perm->mode);
David Howells414c0702008-11-14 10:39:06 +1100705
706 euid = current_euid();
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800707 if (uid_eq(euid, ipcp->cuid) || uid_eq(euid, ipcp->uid) ||
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700708 ns_capable(ns->user_ns, CAP_SYS_ADMIN))
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -0700709 return ipcp; /* successful lookup */
710err:
Pierre Peiffera5f75e72008-04-29 01:00:54 -0700711 return ERR_PTR(err);
712}
713
Will Deaconc1d7e012012-07-30 14:42:46 -0700714#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
Linus Torvalds1da177e2005-04-16 15:20:36 -0700715
716
717/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800718 * ipc_parse_version - ipc call version
719 * @cmd: pointer to command
Linus Torvalds1da177e2005-04-16 15:20:36 -0700720 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800721 * Return IPC_64 for new style IPC and IPC_OLD for old style IPC.
722 * The @cmd value is turned from an encoding command and version into
723 * just the command code.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700724 */
Manfred Spraul239521f2014-01-27 17:07:04 -0800725int ipc_parse_version(int *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700726{
727 if (*cmd & IPC_64) {
728 *cmd ^= IPC_64;
729 return IPC_64;
730 } else {
731 return IPC_OLD;
732 }
733}
734
Will Deaconc1d7e012012-07-30 14:42:46 -0700735#endif /* CONFIG_ARCH_WANT_IPC_PARSE_VERSION */
Mike Waychisonae781772005-09-06 15:17:09 -0700736
737#ifdef CONFIG_PROC_FS
Eric W. Biedermanbc1fc6d2007-02-12 00:52:10 -0800738struct ipc_proc_iter {
739 struct ipc_namespace *ns;
740 struct ipc_proc_iface *iface;
741};
742
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700743/*
744 * This routine locks the ipc structure found at least at position pos.
745 */
Adrian Bunkb524b9a2008-02-06 01:36:28 -0800746static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos,
747 loff_t *new_pos)
Mike Waychisonae781772005-09-06 15:17:09 -0700748{
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700749 struct kern_ipc_perm *ipc;
750 int total, id;
Kirill Korotaev73ea4132006-10-02 02:18:20 -0700751
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700752 total = 0;
753 for (id = 0; id < pos && total < ids->in_use; id++) {
754 ipc = idr_find(&ids->ipcs_idr, id);
755 if (ipc != NULL)
756 total++;
757 }
Mike Waychisonae781772005-09-06 15:17:09 -0700758
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700759 if (total >= ids->in_use)
760 return NULL;
Mike Waychisonae781772005-09-06 15:17:09 -0700761
Manfred Spraul239521f2014-01-27 17:07:04 -0800762 for (; pos < IPCMNI; pos++) {
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700763 ipc = idr_find(&ids->ipcs_idr, pos);
764 if (ipc != NULL) {
765 *new_pos = pos + 1;
Davidlohr Bueso32a27502013-09-11 14:26:29 -0700766 rcu_read_lock();
767 ipc_lock_object(ipc);
Mike Waychisonae781772005-09-06 15:17:09 -0700768 return ipc;
769 }
770 }
771
772 /* Out of range - return NULL to terminate iteration */
773 return NULL;
774}
775
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700776static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos)
777{
778 struct ipc_proc_iter *iter = s->private;
779 struct ipc_proc_iface *iface = iter->iface;
780 struct kern_ipc_perm *ipc = it;
781
782 /* If we had an ipc id locked before, unlock it */
783 if (ipc && ipc != SEQ_START_TOKEN)
784 ipc_unlock(ipc);
785
Pierre Peiffered2ddbf2008-02-08 04:18:57 -0800786 return sysvipc_find_ipc(&iter->ns->ids[iface->ids], *pos, pos);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700787}
788
Mike Waychisonae781772005-09-06 15:17:09 -0700789/*
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700790 * File positions: pos 0 -> header, pos n -> ipc id = n - 1.
791 * SeqFile iterator: iterator value locked ipc pointer or SEQ_TOKEN_START.
Mike Waychisonae781772005-09-06 15:17:09 -0700792 */
793static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos)
794{
Eric W. Biedermanbc1fc6d2007-02-12 00:52:10 -0800795 struct ipc_proc_iter *iter = s->private;
796 struct ipc_proc_iface *iface = iter->iface;
Kirill Korotaev73ea4132006-10-02 02:18:20 -0700797 struct ipc_ids *ids;
798
Pierre Peiffered2ddbf2008-02-08 04:18:57 -0800799 ids = &iter->ns->ids[iface->ids];
Mike Waychisonae781772005-09-06 15:17:09 -0700800
801 /*
802 * Take the lock - this will be released by the corresponding
803 * call to stop().
804 */
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700805 down_read(&ids->rwsem);
Mike Waychisonae781772005-09-06 15:17:09 -0700806
807 /* pos < 0 is invalid */
808 if (*pos < 0)
809 return NULL;
810
811 /* pos == 0 means header */
812 if (*pos == 0)
813 return SEQ_START_TOKEN;
814
815 /* Find the (pos-1)th ipc */
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700816 return sysvipc_find_ipc(ids, *pos - 1, pos);
Mike Waychisonae781772005-09-06 15:17:09 -0700817}
818
819static void sysvipc_proc_stop(struct seq_file *s, void *it)
820{
821 struct kern_ipc_perm *ipc = it;
Eric W. Biedermanbc1fc6d2007-02-12 00:52:10 -0800822 struct ipc_proc_iter *iter = s->private;
823 struct ipc_proc_iface *iface = iter->iface;
Kirill Korotaev73ea4132006-10-02 02:18:20 -0700824 struct ipc_ids *ids;
Mike Waychisonae781772005-09-06 15:17:09 -0700825
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700826 /* If we had a locked structure, release it */
Mike Waychisonae781772005-09-06 15:17:09 -0700827 if (ipc && ipc != SEQ_START_TOKEN)
828 ipc_unlock(ipc);
829
Pierre Peiffered2ddbf2008-02-08 04:18:57 -0800830 ids = &iter->ns->ids[iface->ids];
Mike Waychisonae781772005-09-06 15:17:09 -0700831 /* Release the lock we took in start() */
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700832 up_read(&ids->rwsem);
Mike Waychisonae781772005-09-06 15:17:09 -0700833}
834
835static int sysvipc_proc_show(struct seq_file *s, void *it)
836{
Eric W. Biedermanbc1fc6d2007-02-12 00:52:10 -0800837 struct ipc_proc_iter *iter = s->private;
838 struct ipc_proc_iface *iface = iter->iface;
Mike Waychisonae781772005-09-06 15:17:09 -0700839
Joe Perches7f032d62015-04-15 16:17:54 -0700840 if (it == SEQ_START_TOKEN) {
841 seq_puts(s, iface->header);
842 return 0;
843 }
Mike Waychisonae781772005-09-06 15:17:09 -0700844
845 return iface->show(s, it);
846}
847
James Morris88e9d342009-09-22 16:43:43 -0700848static const struct seq_operations sysvipc_proc_seqops = {
Mike Waychisonae781772005-09-06 15:17:09 -0700849 .start = sysvipc_proc_start,
850 .stop = sysvipc_proc_stop,
851 .next = sysvipc_proc_next,
852 .show = sysvipc_proc_show,
853};
854
Eric W. Biedermanbc1fc6d2007-02-12 00:52:10 -0800855static int sysvipc_proc_open(struct inode *inode, struct file *file)
856{
Eric W. Biedermanbc1fc6d2007-02-12 00:52:10 -0800857 struct ipc_proc_iter *iter;
858
Rob Jonesd66a0522014-10-13 15:54:14 -0700859 iter = __seq_open_private(file, &sysvipc_proc_seqops, sizeof(*iter));
Eric W. Biedermanbc1fc6d2007-02-12 00:52:10 -0800860 if (!iter)
Rob Jonesd66a0522014-10-13 15:54:14 -0700861 return -ENOMEM;
Eric W. Biedermanbc1fc6d2007-02-12 00:52:10 -0800862
Al Virod9dda782013-03-31 18:16:14 -0400863 iter->iface = PDE_DATA(inode);
Eric W. Biedermanbc1fc6d2007-02-12 00:52:10 -0800864 iter->ns = get_ipc_ns(current->nsproxy->ipc_ns);
Rob Jonesd66a0522014-10-13 15:54:14 -0700865
866 return 0;
Eric W. Biedermanbc1fc6d2007-02-12 00:52:10 -0800867}
868
869static int sysvipc_proc_release(struct inode *inode, struct file *file)
870{
871 struct seq_file *seq = file->private_data;
872 struct ipc_proc_iter *iter = seq->private;
873 put_ipc_ns(iter->ns);
874 return seq_release_private(inode, file);
Mike Waychisonae781772005-09-06 15:17:09 -0700875}
876
Arjan van de Ven9a321442007-02-12 00:55:35 -0800877static const struct file_operations sysvipc_proc_fops = {
Mike Waychisonae781772005-09-06 15:17:09 -0700878 .open = sysvipc_proc_open,
879 .read = seq_read,
880 .llseek = seq_lseek,
Eric W. Biedermanbc1fc6d2007-02-12 00:52:10 -0800881 .release = sysvipc_proc_release,
Mike Waychisonae781772005-09-06 15:17:09 -0700882};
883#endif /* CONFIG_PROC_FS */