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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
Nadia Derbey424450c2008-04-29 01:00:43 -070074static void ipc_memory_notifier(struct work_struct *work)
75{
76 ipcns_notify(IPCNS_MEMCHANGED);
77}
78
Nadia Derbeyb6b337a2008-04-29 01:00:42 -070079static int ipc_memory_callback(struct notifier_block *self,
80 unsigned long action, void *arg)
81{
Andrew Morton8f68fa22013-04-29 15:08:05 -070082 static DECLARE_WORK(ipc_memory_wq, ipc_memory_notifier);
83
Nadia Derbeyb6b337a2008-04-29 01:00:42 -070084 switch (action) {
85 case MEM_ONLINE: /* memory successfully brought online */
86 case MEM_OFFLINE: /* or offline: it's time to recompute msgmni */
87 /*
88 * This is done by invoking the ipcns notifier chain with the
89 * IPC_MEMCHANGED event.
Nadia Derbey424450c2008-04-29 01:00:43 -070090 * In order not to keep the lock on the hotplug memory chain
91 * for too long, queue a work item that will, when waken up,
92 * activate the ipcns notification chain.
Nadia Derbeyb6b337a2008-04-29 01:00:42 -070093 */
Xie XiuQi206fa942013-11-12 15:11:46 -080094 schedule_work(&ipc_memory_wq);
Nadia Derbeyb6b337a2008-04-29 01:00:42 -070095 break;
96 case MEM_GOING_ONLINE:
97 case MEM_GOING_OFFLINE:
98 case MEM_CANCEL_ONLINE:
99 case MEM_CANCEL_OFFLINE:
100 default:
101 break;
102 }
103
104 return NOTIFY_OK;
105}
106
Andrew Morton8f68fa22013-04-29 15:08:05 -0700107static struct notifier_block ipc_memory_nb = {
108 .notifier_call = ipc_memory_callback,
109 .priority = IPC_CALLBACK_PRI,
110};
Nadia Derbeyb6b337a2008-04-29 01:00:42 -0700111
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800113 * ipc_init - initialise ipc subsystem
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800115 * The various sysv ipc resources (semaphores, messages and shared
116 * memory) are initialised.
117 *
118 * A callback routine is registered into the memory hotplug notifier
119 * chain: since msgmni scales to lowmem this callback routine will be
120 * called upon successful memory add / remove to recompute msmgni.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122static int __init ipc_init(void)
123{
124 sem_init();
125 msg_init();
126 shm_init();
Andrew Morton8f68fa22013-04-29 15:08:05 -0700127 register_hotmemory_notifier(&ipc_memory_nb);
Nadia Derbeyb6b337a2008-04-29 01:00:42 -0700128 register_ipcns_notifier(&init_ipc_ns);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 return 0;
130}
131__initcall(ipc_init);
132
133/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800134 * ipc_init_ids - initialise ipc identifiers
135 * @ids: ipc identifier set
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800137 * Set up the sequence range to use for the ipc identifier range (limited
138 * below IPCMNI) then initialise the ids idr.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 */
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700140void ipc_init_ids(struct ipc_ids *ids)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 ids->in_use = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143 ids->seq = 0;
Stanislav Kinsbursky03f59562013-01-04 15:34:50 -0800144 ids->next_id = -1;
Davidlohr Buesodaf948c2014-01-27 17:07:09 -0800145 init_rwsem(&ids->rwsem);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700146 idr_init(&ids->ipcs_idr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147}
148
Mike Waychisonae781772005-09-06 15:17:09 -0700149#ifdef CONFIG_PROC_FS
Arjan van de Ven9a321442007-02-12 00:55:35 -0800150static const struct file_operations sysvipc_proc_fops;
Mike Waychisonae781772005-09-06 15:17:09 -0700151/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800152 * ipc_init_proc_interface - create a proc interface for sysipc types using a seq_file interface.
153 * @path: Path in procfs
154 * @header: Banner to be printed at the beginning of the file.
155 * @ids: ipc id table to iterate.
156 * @show: show routine.
Mike Waychisonae781772005-09-06 15:17:09 -0700157 */
158void __init ipc_init_proc_interface(const char *path, const char *header,
Kirill Korotaev73ea4132006-10-02 02:18:20 -0700159 int ids, int (*show)(struct seq_file *, void *))
Mike Waychisonae781772005-09-06 15:17:09 -0700160{
161 struct proc_dir_entry *pde;
162 struct ipc_proc_iface *iface;
163
164 iface = kmalloc(sizeof(*iface), GFP_KERNEL);
165 if (!iface)
166 return;
167 iface->path = path;
168 iface->header = header;
169 iface->ids = ids;
170 iface->show = show;
171
Denis V. Lunev6a6375d2008-04-29 01:02:12 -0700172 pde = proc_create_data(path,
173 S_IRUGO, /* world readable */
174 NULL, /* parent dir */
175 &sysvipc_proc_fops,
176 iface);
Davidlohr Bueso3ab08fe2014-01-27 17:07:06 -0800177 if (!pde)
Mike Waychisonae781772005-09-06 15:17:09 -0700178 kfree(iface);
Mike Waychisonae781772005-09-06 15:17:09 -0700179}
180#endif
181
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800183 * ipc_findkey - find a key in an ipc identifier set
184 * @ids: ipc identifier set
185 * @key: key to find
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800187 * Returns the locked pointer to the ipc structure if found or NULL
188 * otherwise. If key is found ipc points to the owning ipc structure
189 *
190 * Called with ipc_ids.rwsem held.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 */
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700192static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193{
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700194 struct kern_ipc_perm *ipc;
195 int next_id;
196 int total;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700198 for (total = 0, next_id = 0; total < ids->in_use; next_id++) {
199 ipc = idr_find(&ids->ipcs_idr, next_id);
200
201 if (ipc == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202 continue;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700203
204 if (ipc->key != key) {
205 total++;
206 continue;
207 }
208
Davidlohr Bueso32a27502013-09-11 14:26:29 -0700209 rcu_read_lock();
210 ipc_lock_object(ipc);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700211 return ipc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212 }
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700213
214 return NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215}
216
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700217/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800218 * ipc_get_maxid - get the last assigned id
219 * @ids: ipc identifier set
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700220 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800221 * Called with ipc_ids.rwsem held.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222 */
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700223int ipc_get_maxid(struct ipc_ids *ids)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224{
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700225 struct kern_ipc_perm *ipc;
226 int max_id = -1;
227 int total, id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700229 if (ids->in_use == 0)
230 return -1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700232 if (ids->in_use == IPCMNI)
233 return IPCMNI - 1;
234
235 /* Look for the last assigned id */
236 total = 0;
237 for (id = 0; id < IPCMNI && total < ids->in_use; id++) {
238 ipc = idr_find(&ids->ipcs_idr, id);
239 if (ipc != NULL) {
240 max_id = id;
241 total++;
242 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243 }
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700244 return max_id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245}
246
247/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800248 * ipc_addid - add an ipc identifier
249 * @ids: ipc identifier set
250 * @new: new ipc permission set
251 * @size: limit for the number of used ids
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800253 * Add an entry 'new' to the ipc ids idr. The permissions object is
254 * initialised and the first free entry is set up and the id assigned
255 * is returned. The 'new' entry is returned in a locked state on success.
256 * On failure the entry is not locked and a negative err-code is returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800258 * Called with writer ipc_ids.rwsem held.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 */
Manfred Spraul239521f2014-01-27 17:07:04 -0800260int ipc_addid(struct ipc_ids *ids, struct kern_ipc_perm *new, int size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261{
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800262 kuid_t euid;
263 kgid_t egid;
Tejun Heo54924ea2013-02-27 17:04:53 -0800264 int id;
Stanislav Kinsbursky03f59562013-01-04 15:34:50 -0800265 int next_id = ids->next_id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700267 if (size > IPCMNI)
268 size = IPCMNI;
269
270 if (ids->in_use >= size)
Pierre Peiffer283bb7f2007-10-18 23:40:57 -0700271 return -ENOSPC;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700272
Tejun Heo54924ea2013-02-27 17:04:53 -0800273 idr_preload(GFP_KERNEL);
274
Nadia Derbeye00b4ff7e2008-11-19 15:36:08 -0800275 spin_lock_init(&new->lock);
Rafael Aquini72a8ff22014-01-27 17:07:02 -0800276 new->deleted = false;
Nadia Derbeye00b4ff7e2008-11-19 15:36:08 -0800277 rcu_read_lock();
278 spin_lock(&new->lock);
279
Tejun Heo54924ea2013-02-27 17:04:53 -0800280 id = idr_alloc(&ids->ipcs_idr, new,
281 (next_id < 0) ? 0 : ipcid_to_idx(next_id), 0,
282 GFP_NOWAIT);
283 idr_preload_end();
284 if (id < 0) {
Nadia Derbeye00b4ff7e2008-11-19 15:36:08 -0800285 spin_unlock(&new->lock);
286 rcu_read_unlock();
Tejun Heo54924ea2013-02-27 17:04:53 -0800287 return id;
Nadia Derbeye00b4ff7e2008-11-19 15:36:08 -0800288 }
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700289
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290 ids->in_use++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291
David Howells414c0702008-11-14 10:39:06 +1100292 current_euid_egid(&euid, &egid);
293 new->cuid = new->uid = euid;
294 new->gid = new->cgid = egid;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295
Stanislav Kinsbursky03f59562013-01-04 15:34:50 -0800296 if (next_id < 0) {
297 new->seq = ids->seq++;
Davidlohr Buesodaf948c2014-01-27 17:07:09 -0800298 if (ids->seq > IPCID_SEQ_MAX)
Stanislav Kinsbursky03f59562013-01-04 15:34:50 -0800299 ids->seq = 0;
300 } else {
301 new->seq = ipcid_to_seqx(next_id);
302 ids->next_id = -1;
303 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304
Pierre Peiffer48dea402008-04-29 01:00:35 -0700305 new->id = ipc_buildid(id, new->seq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306 return id;
307}
308
309/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800310 * ipcget_new - create a new ipc object
311 * @ns: ipc namespace
312 * @ids: ipc identifer set
313 * @ops: the actual creation routine to call
314 * @params: its parameters
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700315 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800316 * This routine is called by sys_msgget, sys_semget() and sys_shmget()
317 * when the key is IPC_PRIVATE.
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700318 */
Pavel Emelyanovb2d75cd2008-02-08 04:18:54 -0800319static int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids,
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700320 struct ipc_ops *ops, struct ipc_params *params)
321{
322 int err;
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700323
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700324 down_write(&ids->rwsem);
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700325 err = ops->getnew(ns, params);
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700326 up_write(&ids->rwsem);
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700327 return err;
328}
329
330/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800331 * ipc_check_perms - check security and permissions for an ipc object
332 * @ns: ipc namespace
333 * @ipcp: ipc permission set
334 * @ops: the actual security routine to call
335 * @params: its parameters
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700336 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800337 * This routine is called by sys_msgget(), sys_semget() and sys_shmget()
338 * when the key is not IPC_PRIVATE and that key already exists in the
339 * ds IDR.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700340 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800341 * On success, the ipc id is returned.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700342 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800343 * It is called with ipc_ids.rwsem and ipcp->lock held.
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700344 */
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700345static int ipc_check_perms(struct ipc_namespace *ns,
346 struct kern_ipc_perm *ipcp,
347 struct ipc_ops *ops,
348 struct ipc_params *params)
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700349{
350 int err;
351
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700352 if (ipcperms(ns, ipcp, params->flg))
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700353 err = -EACCES;
354 else {
355 err = ops->associate(ipcp, params->flg);
356 if (!err)
357 err = ipcp->id;
358 }
359
360 return err;
361}
362
363/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800364 * ipcget_public - get an ipc object or create a new one
365 * @ns: ipc namespace
366 * @ids: ipc identifer set
367 * @ops: the actual creation routine to call
368 * @params: its parameters
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700369 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800370 * This routine is called by sys_msgget, sys_semget() and sys_shmget()
371 * when the key is not IPC_PRIVATE.
372 * It adds a new entry if the key is not found and does some permission
373 * / security checkings if the key is found.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700374 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800375 * On success, the ipc id is returned.
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700376 */
Pavel Emelyanovb2d75cd2008-02-08 04:18:54 -0800377static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids,
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700378 struct ipc_ops *ops, struct ipc_params *params)
379{
380 struct kern_ipc_perm *ipcp;
381 int flg = params->flg;
382 int err;
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700383
Nadia Derbey3e148c72007-10-18 23:40:54 -0700384 /*
385 * Take the lock as a writer since we are potentially going to add
386 * a new entry + read locks are not "upgradable"
387 */
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700388 down_write(&ids->rwsem);
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700389 ipcp = ipc_findkey(ids, params->key);
390 if (ipcp == NULL) {
391 /* key not used */
392 if (!(flg & IPC_CREAT))
393 err = -ENOENT;
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700394 else
395 err = ops->getnew(ns, params);
396 } else {
397 /* ipc object has been locked by ipc_findkey() */
398
399 if (flg & IPC_CREAT && flg & IPC_EXCL)
400 err = -EEXIST;
401 else {
402 err = 0;
403 if (ops->more_checks)
404 err = ops->more_checks(ipcp, params);
405 if (!err)
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700406 /*
407 * ipc_check_perms returns the IPC id on
408 * success
409 */
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700410 err = ipc_check_perms(ns, ipcp, ops, params);
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700411 }
412 ipc_unlock(ipcp);
413 }
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700414 up_write(&ids->rwsem);
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700415
416 return err;
417}
418
419
420/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800421 * ipc_rmid - remove an ipc identifier
422 * @ids: ipc identifier set
423 * @ipcp: ipc perm structure containing the identifier to remove
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800425 * ipc_ids.rwsem (as a writer) and the spinlock for this ID are held
426 * before this function is called, and remain locked on the exit.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427 */
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700428void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700429{
Nadia Derbeyce621f52007-10-18 23:40:52 -0700430 int lid = ipcid_to_idx(ipcp->id);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700432 idr_remove(&ids->ipcs_idr, lid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433 ids->in_use--;
Rafael Aquini72a8ff22014-01-27 17:07:02 -0800434 ipcp->deleted = true;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435}
436
437/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800438 * ipc_alloc - allocate ipc space
439 * @size: size desired
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800441 * Allocate memory from the appropriate pools and return a pointer to it.
442 * NULL is returned if the allocation fails
Linus Torvalds1da177e2005-04-16 15:20:36 -0700443 */
Rik van Riel6062a8d2013-04-30 19:15:44 -0700444void *ipc_alloc(int size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700445{
Rik van Riel6062a8d2013-04-30 19:15:44 -0700446 void *out;
Manfred Spraul239521f2014-01-27 17:07:04 -0800447 if (size > PAGE_SIZE)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448 out = vmalloc(size);
449 else
450 out = kmalloc(size, GFP_KERNEL);
451 return out;
452}
453
454/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800455 * ipc_free - free ipc space
456 * @ptr: pointer returned by ipc_alloc
457 * @size: size of block
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800459 * Free a block created with ipc_alloc(). The caller must know the size
460 * used in the allocation call.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461 */
Manfred Spraul239521f2014-01-27 17:07:04 -0800462void ipc_free(void *ptr, int size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463{
Manfred Spraul239521f2014-01-27 17:07:04 -0800464 if (size > PAGE_SIZE)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465 vfree(ptr);
466 else
467 kfree(ptr);
468}
469
Linus Torvalds1da177e2005-04-16 15:20:36 -0700470/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800471 * ipc_rcu_alloc - allocate ipc and rcu space
472 * @size: size desired
Linus Torvalds1da177e2005-04-16 15:20:36 -0700473 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800474 * Allocate memory for the rcu header structure + the object.
475 * Returns the pointer to the object or NULL upon failure.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476 */
Rik van Riel6062a8d2013-04-30 19:15:44 -0700477void *ipc_rcu_alloc(int size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478{
Rik van Riel6062a8d2013-04-30 19:15:44 -0700479 /*
Al Viro600fe972013-04-29 12:42:09 -0400480 * We prepend the allocation with the rcu struct
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481 */
Al Viro600fe972013-04-29 12:42:09 -0400482 struct ipc_rcu *out = ipc_alloc(sizeof(struct ipc_rcu) + size);
483 if (unlikely(!out))
484 return NULL;
485 atomic_set(&out->refcount, 1);
Manfred Spraul196aa012013-07-08 16:01:20 -0700486 return out + 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700487}
488
Rik van Riel6062a8d2013-04-30 19:15:44 -0700489int ipc_rcu_getref(void *ptr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490{
Manfred Spraul196aa012013-07-08 16:01:20 -0700491 struct ipc_rcu *p = ((struct ipc_rcu *)ptr) - 1;
492
493 return atomic_inc_not_zero(&p->refcount);
David Howells65f27f32006-11-22 14:55:48 +0000494}
495
Davidlohr Bueso53dad6d2013-09-23 17:04:45 -0700496void ipc_rcu_putref(void *ptr, void (*func)(struct rcu_head *head))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497{
Manfred Spraul196aa012013-07-08 16:01:20 -0700498 struct ipc_rcu *p = ((struct ipc_rcu *)ptr) - 1;
Al Viro600fe972013-04-29 12:42:09 -0400499
500 if (!atomic_dec_and_test(&p->refcount))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501 return;
502
Davidlohr Bueso53dad6d2013-09-23 17:04:45 -0700503 call_rcu(&p->rcu, func);
504}
505
506void ipc_rcu_free(struct rcu_head *head)
507{
508 struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu);
509
510 if (is_vmalloc_addr(p))
511 vfree(p);
512 else
513 kfree(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700514}
515
516/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800517 * ipcperms - check ipc permissions
518 * @ns: ipc namespace
519 * @ipcp: ipc permission set
520 * @flag: desired permission set
Linus Torvalds1da177e2005-04-16 15:20:36 -0700521 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800522 * Check user, group, other permissions for access
523 * to ipc resources. return 0 if allowed
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700524 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800525 * @flag will most probably be 0 or S_...UGO from <linux/stat.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 */
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700527int ipcperms(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp, short flag)
528{
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800529 kuid_t euid = current_euid();
Al Viroa33e6752008-12-10 03:40:06 -0500530 int requested_mode, granted_mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531
Al Viroa33e6752008-12-10 03:40:06 -0500532 audit_ipc_obj(ipcp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533 requested_mode = (flag >> 6) | (flag >> 3) | flag;
534 granted_mode = ipcp->mode;
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800535 if (uid_eq(euid, ipcp->cuid) ||
536 uid_eq(euid, ipcp->uid))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537 granted_mode >>= 6;
538 else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid))
539 granted_mode >>= 3;
540 /* is there some bit set in requested_mode but not in granted_mode? */
541 if ((requested_mode & ~granted_mode & 0007) &&
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700542 !ns_capable(ns->user_ns, CAP_IPC_OWNER))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543 return -1;
544
545 return security_ipc_permission(ipcp, flag);
546}
547
548/*
549 * Functions to convert between the kern_ipc_perm structure and the
550 * old/new ipc_perm structures
551 */
552
553/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800554 * kernel_to_ipc64_perm - convert kernel ipc permissions to user
555 * @in: kernel permissions
556 * @out: new style ipc permissions
Linus Torvalds1da177e2005-04-16 15:20:36 -0700557 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800558 * Turn the kernel object @in into a set of permissions descriptions
559 * for returning to userspace (@out).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 */
Manfred Spraul239521f2014-01-27 17:07:04 -0800561void kernel_to_ipc64_perm(struct kern_ipc_perm *in, struct ipc64_perm *out)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562{
563 out->key = in->key;
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800564 out->uid = from_kuid_munged(current_user_ns(), in->uid);
565 out->gid = from_kgid_munged(current_user_ns(), in->gid);
566 out->cuid = from_kuid_munged(current_user_ns(), in->cuid);
567 out->cgid = from_kgid_munged(current_user_ns(), in->cgid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568 out->mode = in->mode;
569 out->seq = in->seq;
570}
571
572/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800573 * ipc64_perm_to_ipc_perm - convert new ipc permissions to old
574 * @in: new style ipc permissions
575 * @out: old style ipc permissions
Linus Torvalds1da177e2005-04-16 15:20:36 -0700576 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800577 * Turn the new style permissions object @in into a compatibility
578 * object and store it into the @out pointer.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700579 */
Manfred Spraul239521f2014-01-27 17:07:04 -0800580void ipc64_perm_to_ipc_perm(struct ipc64_perm *in, struct ipc_perm *out)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581{
582 out->key = in->key;
583 SET_UID(out->uid, in->uid);
584 SET_GID(out->gid, in->gid);
585 SET_UID(out->cuid, in->cuid);
586 SET_GID(out->cgid, in->cgid);
587 out->mode = in->mode;
588 out->seq = in->seq;
589}
590
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700591/**
Davidlohr Bueso4d2bff52013-04-30 19:15:19 -0700592 * ipc_obtain_object
593 * @ids: ipc identifier set
594 * @id: ipc id to look for
595 *
596 * Look for an id in the ipc ids idr and return associated ipc object.
597 *
598 * Call inside the RCU critical section.
599 * The ipc object is *not* locked on exit.
600 */
601struct kern_ipc_perm *ipc_obtain_object(struct ipc_ids *ids, int id)
602{
603 struct kern_ipc_perm *out;
604 int lid = ipcid_to_idx(id);
605
606 out = idr_find(&ids->ipcs_idr, lid);
607 if (!out)
608 return ERR_PTR(-EINVAL);
609
610 return out;
611}
612
613/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800614 * ipc_lock - lock an ipc structure without rwsem held
615 * @ids: ipc identifier set
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700616 * @id: ipc id to look for
617 *
618 * Look for an id in the ipc ids idr and lock the associated ipc object.
619 *
Davidlohr Bueso4d2bff52013-04-30 19:15:19 -0700620 * The ipc object is locked on successful exit.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700621 */
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700622struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700623{
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700624 struct kern_ipc_perm *out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700625
626 rcu_read_lock();
Davidlohr Bueso4d2bff52013-04-30 19:15:19 -0700627 out = ipc_obtain_object(ids, id);
628 if (IS_ERR(out))
629 goto err1;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700630
Linus Torvalds1da177e2005-04-16 15:20:36 -0700631 spin_lock(&out->lock);
Davidlohr Bueso4d2bff52013-04-30 19:15:19 -0700632
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633 /* ipc_rmid() may have already freed the ID while ipc_lock
634 * was spinning: here verify that the structure is still valid
635 */
Rafael Aquini72a8ff22014-01-27 17:07:02 -0800636 if (ipc_valid_object(out))
Davidlohr Bueso4d2bff52013-04-30 19:15:19 -0700637 return out;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700638
Davidlohr Bueso4d2bff52013-04-30 19:15:19 -0700639 spin_unlock(&out->lock);
640 out = ERR_PTR(-EINVAL);
641err1:
642 rcu_read_unlock();
643 return out;
644}
645
646/**
647 * ipc_obtain_object_check
648 * @ids: ipc identifier set
649 * @id: ipc id to look for
650 *
651 * Similar to ipc_obtain_object() but also checks
652 * the ipc object reference counter.
653 *
654 * Call inside the RCU critical section.
655 * The ipc object is *not* locked on exit.
656 */
657struct kern_ipc_perm *ipc_obtain_object_check(struct ipc_ids *ids, int id)
658{
659 struct kern_ipc_perm *out = ipc_obtain_object(ids, id);
660
661 if (IS_ERR(out))
662 goto out;
663
664 if (ipc_checkid(out, id))
665 return ERR_PTR(-EIDRM);
666out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667 return out;
668}
669
Pavel Emelyanovb2d75cd2008-02-08 04:18:54 -0800670/**
671 * ipcget - Common sys_*get() code
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800672 * @ns: namsepace
673 * @ids: ipc identifier set
674 * @ops: operations to be called on ipc object creation, permission checks
675 * and further checks
676 * @params: the parameters needed by the previous operations.
Pavel Emelyanovb2d75cd2008-02-08 04:18:54 -0800677 *
678 * Common routine called by sys_msgget(), sys_semget() and sys_shmget().
679 */
680int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids,
681 struct ipc_ops *ops, struct ipc_params *params)
682{
683 if (params->key == IPC_PRIVATE)
684 return ipcget_new(ns, ids, ops, params);
685 else
686 return ipcget_public(ns, ids, ops, params);
687}
688
Pierre Peiffer8f4a3802008-04-29 01:00:51 -0700689/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800690 * ipc_update_perm - update the permissions of an ipc object
Pierre Peiffer8f4a3802008-04-29 01:00:51 -0700691 * @in: the permission given as input.
692 * @out: the permission of the ipc to set.
693 */
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800694int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out)
Pierre Peiffer8f4a3802008-04-29 01:00:51 -0700695{
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800696 kuid_t uid = make_kuid(current_user_ns(), in->uid);
697 kgid_t gid = make_kgid(current_user_ns(), in->gid);
698 if (!uid_valid(uid) || !gid_valid(gid))
699 return -EINVAL;
700
701 out->uid = uid;
702 out->gid = gid;
Pierre Peiffer8f4a3802008-04-29 01:00:51 -0700703 out->mode = (out->mode & ~S_IRWXUGO)
704 | (in->mode & S_IRWXUGO);
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800705
706 return 0;
Pierre Peiffer8f4a3802008-04-29 01:00:51 -0700707}
708
Pierre Peiffera5f75e72008-04-29 01:00:54 -0700709/**
Davidlohr Bueso3b1c4ad2013-09-11 14:26:17 -0700710 * ipcctl_pre_down_nolock - retrieve an ipc and check permissions for some IPC_XXX cmd
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800711 * @ns: ipc namespace
Pierre Peiffera5f75e72008-04-29 01:00:54 -0700712 * @ids: the table of ids where to look for the ipc
713 * @id: the id of the ipc to retrieve
714 * @cmd: the cmd to check
715 * @perm: the permission to set
716 * @extra_perm: one extra permission parameter used by msq
717 *
718 * This function does some common audit and permissions check for some IPC_XXX
719 * cmd and is called from semctl_down, shmctl_down and msgctl_down.
720 * It must be called without any lock held and
721 * - retrieves the ipc with the given id in the given table.
722 * - performs some audit and permission check, depending on the given cmd
Davidlohr Bueso3b1c4ad2013-09-11 14:26:17 -0700723 * - returns a pointer to the ipc object or otherwise, the corresponding error.
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -0700724 *
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700725 * Call holding the both the rwsem and the rcu read lock.
Pierre Peiffera5f75e72008-04-29 01:00:54 -0700726 */
Davidlohr Bueso444d0f62013-04-30 19:15:24 -0700727struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns,
Davidlohr Bueso3b1c4ad2013-09-11 14:26:17 -0700728 struct ipc_ids *ids, int id, int cmd,
729 struct ipc64_perm *perm, int extra_perm)
Davidlohr Bueso444d0f62013-04-30 19:15:24 -0700730{
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800731 kuid_t euid;
Davidlohr Bueso444d0f62013-04-30 19:15:24 -0700732 int err = -EPERM;
733 struct kern_ipc_perm *ipcp;
Pierre Peiffera5f75e72008-04-29 01:00:54 -0700734
Davidlohr Bueso444d0f62013-04-30 19:15:24 -0700735 ipcp = ipc_obtain_object_check(ids, id);
Pierre Peiffera5f75e72008-04-29 01:00:54 -0700736 if (IS_ERR(ipcp)) {
737 err = PTR_ERR(ipcp);
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -0700738 goto err;
Pierre Peiffera5f75e72008-04-29 01:00:54 -0700739 }
740
Al Viroa33e6752008-12-10 03:40:06 -0500741 audit_ipc_obj(ipcp);
Al Viroe816f372008-12-10 03:47:15 -0500742 if (cmd == IPC_SET)
743 audit_ipc_set_perm(extra_perm, perm->uid,
Davidlohr Bueso444d0f62013-04-30 19:15:24 -0700744 perm->gid, perm->mode);
David Howells414c0702008-11-14 10:39:06 +1100745
746 euid = current_euid();
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800747 if (uid_eq(euid, ipcp->cuid) || uid_eq(euid, ipcp->uid) ||
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700748 ns_capable(ns->user_ns, CAP_SYS_ADMIN))
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -0700749 return ipcp; /* successful lookup */
750err:
Pierre Peiffera5f75e72008-04-29 01:00:54 -0700751 return ERR_PTR(err);
752}
753
Will Deaconc1d7e012012-07-30 14:42:46 -0700754#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
Linus Torvalds1da177e2005-04-16 15:20:36 -0700755
756
757/**
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800758 * ipc_parse_version - ipc call version
759 * @cmd: pointer to command
Linus Torvalds1da177e2005-04-16 15:20:36 -0700760 *
Davidlohr Bueso8001c852014-01-27 17:07:05 -0800761 * Return IPC_64 for new style IPC and IPC_OLD for old style IPC.
762 * The @cmd value is turned from an encoding command and version into
763 * just the command code.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700764 */
Manfred Spraul239521f2014-01-27 17:07:04 -0800765int ipc_parse_version(int *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700766{
767 if (*cmd & IPC_64) {
768 *cmd ^= IPC_64;
769 return IPC_64;
770 } else {
771 return IPC_OLD;
772 }
773}
774
Will Deaconc1d7e012012-07-30 14:42:46 -0700775#endif /* CONFIG_ARCH_WANT_IPC_PARSE_VERSION */
Mike Waychisonae781772005-09-06 15:17:09 -0700776
777#ifdef CONFIG_PROC_FS
Eric W. Biedermanbc1fc6d2007-02-12 00:52:10 -0800778struct ipc_proc_iter {
779 struct ipc_namespace *ns;
780 struct ipc_proc_iface *iface;
781};
782
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700783/*
784 * This routine locks the ipc structure found at least at position pos.
785 */
Adrian Bunkb524b9a2008-02-06 01:36:28 -0800786static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos,
787 loff_t *new_pos)
Mike Waychisonae781772005-09-06 15:17:09 -0700788{
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700789 struct kern_ipc_perm *ipc;
790 int total, id;
Kirill Korotaev73ea4132006-10-02 02:18:20 -0700791
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700792 total = 0;
793 for (id = 0; id < pos && total < ids->in_use; id++) {
794 ipc = idr_find(&ids->ipcs_idr, id);
795 if (ipc != NULL)
796 total++;
797 }
Mike Waychisonae781772005-09-06 15:17:09 -0700798
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700799 if (total >= ids->in_use)
800 return NULL;
Mike Waychisonae781772005-09-06 15:17:09 -0700801
Manfred Spraul239521f2014-01-27 17:07:04 -0800802 for (; pos < IPCMNI; pos++) {
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700803 ipc = idr_find(&ids->ipcs_idr, pos);
804 if (ipc != NULL) {
805 *new_pos = pos + 1;
Davidlohr Bueso32a27502013-09-11 14:26:29 -0700806 rcu_read_lock();
807 ipc_lock_object(ipc);
Mike Waychisonae781772005-09-06 15:17:09 -0700808 return ipc;
809 }
810 }
811
812 /* Out of range - return NULL to terminate iteration */
813 return NULL;
814}
815
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700816static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos)
817{
818 struct ipc_proc_iter *iter = s->private;
819 struct ipc_proc_iface *iface = iter->iface;
820 struct kern_ipc_perm *ipc = it;
821
822 /* If we had an ipc id locked before, unlock it */
823 if (ipc && ipc != SEQ_START_TOKEN)
824 ipc_unlock(ipc);
825
Pierre Peiffered2ddbf2008-02-08 04:18:57 -0800826 return sysvipc_find_ipc(&iter->ns->ids[iface->ids], *pos, pos);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700827}
828
Mike Waychisonae781772005-09-06 15:17:09 -0700829/*
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700830 * File positions: pos 0 -> header, pos n -> ipc id = n - 1.
831 * SeqFile iterator: iterator value locked ipc pointer or SEQ_TOKEN_START.
Mike Waychisonae781772005-09-06 15:17:09 -0700832 */
833static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos)
834{
Eric W. Biedermanbc1fc6d2007-02-12 00:52:10 -0800835 struct ipc_proc_iter *iter = s->private;
836 struct ipc_proc_iface *iface = iter->iface;
Kirill Korotaev73ea4132006-10-02 02:18:20 -0700837 struct ipc_ids *ids;
838
Pierre Peiffered2ddbf2008-02-08 04:18:57 -0800839 ids = &iter->ns->ids[iface->ids];
Mike Waychisonae781772005-09-06 15:17:09 -0700840
841 /*
842 * Take the lock - this will be released by the corresponding
843 * call to stop().
844 */
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700845 down_read(&ids->rwsem);
Mike Waychisonae781772005-09-06 15:17:09 -0700846
847 /* pos < 0 is invalid */
848 if (*pos < 0)
849 return NULL;
850
851 /* pos == 0 means header */
852 if (*pos == 0)
853 return SEQ_START_TOKEN;
854
855 /* Find the (pos-1)th ipc */
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700856 return sysvipc_find_ipc(ids, *pos - 1, pos);
Mike Waychisonae781772005-09-06 15:17:09 -0700857}
858
859static void sysvipc_proc_stop(struct seq_file *s, void *it)
860{
861 struct kern_ipc_perm *ipc = it;
Eric W. Biedermanbc1fc6d2007-02-12 00:52:10 -0800862 struct ipc_proc_iter *iter = s->private;
863 struct ipc_proc_iface *iface = iter->iface;
Kirill Korotaev73ea4132006-10-02 02:18:20 -0700864 struct ipc_ids *ids;
Mike Waychisonae781772005-09-06 15:17:09 -0700865
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700866 /* If we had a locked structure, release it */
Mike Waychisonae781772005-09-06 15:17:09 -0700867 if (ipc && ipc != SEQ_START_TOKEN)
868 ipc_unlock(ipc);
869
Pierre Peiffered2ddbf2008-02-08 04:18:57 -0800870 ids = &iter->ns->ids[iface->ids];
Mike Waychisonae781772005-09-06 15:17:09 -0700871 /* Release the lock we took in start() */
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700872 up_read(&ids->rwsem);
Mike Waychisonae781772005-09-06 15:17:09 -0700873}
874
875static int sysvipc_proc_show(struct seq_file *s, void *it)
876{
Eric W. Biedermanbc1fc6d2007-02-12 00:52:10 -0800877 struct ipc_proc_iter *iter = s->private;
878 struct ipc_proc_iface *iface = iter->iface;
Mike Waychisonae781772005-09-06 15:17:09 -0700879
880 if (it == SEQ_START_TOKEN)
881 return seq_puts(s, iface->header);
882
883 return iface->show(s, it);
884}
885
James Morris88e9d342009-09-22 16:43:43 -0700886static const struct seq_operations sysvipc_proc_seqops = {
Mike Waychisonae781772005-09-06 15:17:09 -0700887 .start = sysvipc_proc_start,
888 .stop = sysvipc_proc_stop,
889 .next = sysvipc_proc_next,
890 .show = sysvipc_proc_show,
891};
892
Eric W. Biedermanbc1fc6d2007-02-12 00:52:10 -0800893static int sysvipc_proc_open(struct inode *inode, struct file *file)
894{
Mike Waychisonae781772005-09-06 15:17:09 -0700895 int ret;
896 struct seq_file *seq;
Eric W. Biedermanbc1fc6d2007-02-12 00:52:10 -0800897 struct ipc_proc_iter *iter;
898
899 ret = -ENOMEM;
900 iter = kmalloc(sizeof(*iter), GFP_KERNEL);
901 if (!iter)
902 goto out;
Mike Waychisonae781772005-09-06 15:17:09 -0700903
904 ret = seq_open(file, &sysvipc_proc_seqops);
Davidlohr Bueso8dc5cd02014-01-27 17:07:08 -0800905 if (ret) {
906 kfree(iter);
907 goto out;
908 }
Eric W. Biedermanbc1fc6d2007-02-12 00:52:10 -0800909
910 seq = file->private_data;
911 seq->private = iter;
912
Al Virod9dda782013-03-31 18:16:14 -0400913 iter->iface = PDE_DATA(inode);
Eric W. Biedermanbc1fc6d2007-02-12 00:52:10 -0800914 iter->ns = get_ipc_ns(current->nsproxy->ipc_ns);
915out:
Mike Waychisonae781772005-09-06 15:17:09 -0700916 return ret;
Eric W. Biedermanbc1fc6d2007-02-12 00:52:10 -0800917}
918
919static int sysvipc_proc_release(struct inode *inode, struct file *file)
920{
921 struct seq_file *seq = file->private_data;
922 struct ipc_proc_iter *iter = seq->private;
923 put_ipc_ns(iter->ns);
924 return seq_release_private(inode, file);
Mike Waychisonae781772005-09-06 15:17:09 -0700925}
926
Arjan van de Ven9a321442007-02-12 00:55:35 -0800927static const struct file_operations sysvipc_proc_fops = {
Mike Waychisonae781772005-09-06 15:17:09 -0700928 .open = sysvipc_proc_open,
929 .read = seq_read,
930 .llseek = seq_lseek,
Eric W. Biedermanbc1fc6d2007-02-12 00:52:10 -0800931 .release = sysvipc_proc_release,
Mike Waychisonae781772005-09-06 15:17:09 -0700932};
933#endif /* CONFIG_PROC_FS */