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Greg Kroah-Hartmanb2441312017-11-01 15:07:57 +01001// SPDX-License-Identifier: GPL-2.0
Linus Torvalds1da177e2005-04-16 15:20:36 -07002/*
3 * linux/ipc/shm.c
4 * Copyright (C) 1992, 1993 Krishna Balasubramanian
5 * Many improvements/fixes by Bruno Haible.
6 * Replaced `struct shm_desc' by `struct vm_area_struct', July 1994.
7 * Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli.
8 *
9 * /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
10 * BIGMEM support, Andrea Arcangeli <andrea@suse.de>
11 * SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr>
12 * HIGHMEM support, Ingo Molnar <mingo@redhat.com>
13 * Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <cr@sap.com>
14 * Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com>
15 * Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com>
16 *
Steve Grubb073115d2006-04-02 17:07:33 -040017 * support for audit of ipc object properties and permission changes
18 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
Kirill Korotaev4e982312006-10-02 02:18:22 -070019 *
20 * namespaces support
21 * OpenVZ, SWsoft Inc.
22 * Pavel Emelianov <xemul@openvz.org>
Davidlohr Buesoc2c737a2013-09-11 14:26:23 -070023 *
24 * Better ipc lock (kern_ipc_perm.lock) handling
25 * Davidlohr Bueso <davidlohr.bueso@hp.com>, June 2013.
Linus Torvalds1da177e2005-04-16 15:20:36 -070026 */
27
Linus Torvalds1da177e2005-04-16 15:20:36 -070028#include <linux/slab.h>
29#include <linux/mm.h>
30#include <linux/hugetlb.h>
31#include <linux/shm.h>
32#include <linux/init.h>
33#include <linux/file.h>
34#include <linux/mman.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070035#include <linux/shmem_fs.h>
36#include <linux/security.h>
37#include <linux/syscalls.h>
38#include <linux/audit.h>
Randy.Dunlapc59ede72006-01-11 12:17:46 -080039#include <linux/capability.h>
Stephen Rothwell7d87e14c2005-05-01 08:59:12 -070040#include <linux/ptrace.h>
Mike Waychison19b49462005-09-06 15:17:10 -070041#include <linux/seq_file.h>
Nadia Derbey3e148c72007-10-18 23:40:54 -070042#include <linux/rwsem.h>
Kirill Korotaev4e982312006-10-02 02:18:22 -070043#include <linux/nsproxy.h>
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -080044#include <linux/mount.h>
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -080045#include <linux/ipc_namespace.h>
NeilBrown0eb71a92018-06-18 12:52:50 +100046#include <linux/rhashtable.h>
Stephen Rothwell7d87e14c2005-05-01 08:59:12 -070047
Paul McQuade7153e402014-06-06 14:37:37 -070048#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070049
50#include "util.h"
51
Eric W. Biedermana2e102c2018-03-22 21:34:44 -050052struct shmid_kernel /* private to the kernel */
53{
54 struct kern_ipc_perm shm_perm;
55 struct file *shm_file;
56 unsigned long shm_nattch;
57 unsigned long shm_segsz;
58 time64_t shm_atim;
59 time64_t shm_dtim;
60 time64_t shm_ctim;
Eric W. Biederman98f929b12018-03-23 00:29:57 -050061 struct pid *shm_cprid;
62 struct pid *shm_lprid;
Alexey Gladkovd7c9e992021-04-22 14:27:14 +020063 struct ucounts *mlock_ucounts;
Eric W. Biedermana2e102c2018-03-22 21:34:44 -050064
Alexander Mikhalitsyn85b6d2462021-11-19 16:43:21 -080065 /*
66 * The task created the shm object, for
67 * task_lock(shp->shm_creator)
68 */
Eric W. Biedermana2e102c2018-03-22 21:34:44 -050069 struct task_struct *shm_creator;
Alexander Mikhalitsyn85b6d2462021-11-19 16:43:21 -080070
71 /*
72 * List by creator. task_lock(->shm_creator) required for read/write.
73 * If list_empty(), then the creator is dead already.
74 */
75 struct list_head shm_clist;
76 struct ipc_namespace *ns;
Eric W. Biedermana2e102c2018-03-22 21:34:44 -050077} __randomize_layout;
78
79/* shm_mode upper byte flags */
80#define SHM_DEST 01000 /* segment will be destroyed on last detach */
81#define SHM_LOCKED 02000 /* segment will not be swapped */
82
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -080083struct shm_file_data {
84 int id;
85 struct ipc_namespace *ns;
86 struct file *file;
87 const struct vm_operations_struct *vm_ops;
88};
89
90#define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
91
Arjan van de Ven9a321442007-02-12 00:55:35 -080092static const struct file_operations shm_file_operations;
Alexey Dobriyanf0f37e2f2009-09-27 22:29:37 +040093static const struct vm_operations_struct shm_vm_ops;
Linus Torvalds1da177e2005-04-16 15:20:36 -070094
Pierre Peiffered2ddbf2008-02-08 04:18:57 -080095#define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS])
Linus Torvalds1da177e2005-04-16 15:20:36 -070096
Kirill Korotaev4e982312006-10-02 02:18:22 -070097#define shm_unlock(shp) \
98 ipc_unlock(&(shp)->shm_perm)
Kirill Korotaev4e982312006-10-02 02:18:22 -070099
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700100static int newseg(struct ipc_namespace *, struct ipc_params *);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800101static void shm_open(struct vm_area_struct *vma);
102static void shm_close(struct vm_area_struct *vma);
Manfred Spraul239521f2014-01-27 17:07:04 -0800103static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104#ifdef CONFIG_PROC_FS
Mike Waychison19b49462005-09-06 15:17:10 -0700105static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106#endif
107
Davidlohr Buesoeae04d22018-08-21 22:01:56 -0700108void shm_init_ns(struct ipc_namespace *ns)
Kirill Korotaev4e982312006-10-02 02:18:22 -0700109{
Kirill Korotaev4e982312006-10-02 02:18:22 -0700110 ns->shm_ctlmax = SHMMAX;
111 ns->shm_ctlall = SHMALL;
112 ns->shm_ctlmni = SHMMNI;
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700113 ns->shm_rmid_forced = 0;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700114 ns->shm_tot = 0;
Davidlohr Buesoeae04d22018-08-21 22:01:56 -0700115 ipc_init_ids(&shm_ids(ns));
Kirill Korotaev4e982312006-10-02 02:18:22 -0700116}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700118/*
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700119 * Called with shm_ids.rwsem (writer) and the shp structure locked.
120 * Only shm_ids.rwsem remains locked on exit.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700121 */
Pierre Peiffer01b8b072008-02-08 04:18:57 -0800122static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
Kirill Korotaev4e982312006-10-02 02:18:22 -0700123{
Pierre Peiffer01b8b072008-02-08 04:18:57 -0800124 struct shmid_kernel *shp;
Shailesh Pandey63980c82016-12-14 15:06:10 -0800125
Pierre Peiffer01b8b072008-02-08 04:18:57 -0800126 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
Alexander Mikhalitsyn85b6d2462021-11-19 16:43:21 -0800127 WARN_ON(ns != shp->ns);
Pierre Peiffer01b8b072008-02-08 04:18:57 -0800128
Manfred Spraul239521f2014-01-27 17:07:04 -0800129 if (shp->shm_nattch) {
Kirill Korotaev4e982312006-10-02 02:18:22 -0700130 shp->shm_perm.mode |= SHM_DEST;
131 /* Do not find it any more */
Guillaume Knispel0cfb6ae2017-09-08 16:17:55 -0700132 ipc_set_key_private(&shm_ids(ns), &shp->shm_perm);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700133 shm_unlock(shp);
134 } else
135 shm_destroy(ns, shp);
136}
137
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800138#ifdef CONFIG_IPC_NS
Kirill Korotaev4e982312006-10-02 02:18:22 -0700139void shm_exit_ns(struct ipc_namespace *ns)
140{
Pierre Peiffer01b8b072008-02-08 04:18:57 -0800141 free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
Serge E. Hallyn7d6feeb2009-12-15 16:47:27 -0800142 idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
Guillaume Knispel0cfb6ae2017-09-08 16:17:55 -0700143 rhashtable_destroy(&ns->ids[IPC_SHM_IDS].key_ht);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700144}
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800145#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146
Linus Torvalds140d0b22011-08-04 19:35:59 -1000147static int __init ipc_ns_init(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148{
Davidlohr Buesoeae04d22018-08-21 22:01:56 -0700149 shm_init_ns(&init_ipc_ns);
150 return 0;
Linus Torvalds140d0b22011-08-04 19:35:59 -1000151}
152
153pure_initcall(ipc_ns_init);
154
Manfred Spraul239521f2014-01-27 17:07:04 -0800155void __init shm_init(void)
Linus Torvalds140d0b22011-08-04 19:35:59 -1000156{
Mike Waychison19b49462005-09-06 15:17:10 -0700157 ipc_init_proc_interface("sysvipc/shm",
Helge Dellerb7952182010-10-27 15:34:16 -0700158#if BITS_PER_LONG <= 32
159 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
160#else
161 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
162#endif
Kirill Korotaev4e982312006-10-02 02:18:22 -0700163 IPC_SHM_IDS, sysvipc_shm_proc_show);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164}
165
Davidlohr Bueso8b8d52a2013-09-11 14:26:15 -0700166static inline struct shmid_kernel *shm_obtain_object(struct ipc_namespace *ns, int id)
167{
Davidlohr Bueso55b7ae52015-06-30 14:58:42 -0700168 struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(&shm_ids(ns), id);
Davidlohr Bueso8b8d52a2013-09-11 14:26:15 -0700169
170 if (IS_ERR(ipcp))
171 return ERR_CAST(ipcp);
172
173 return container_of(ipcp, struct shmid_kernel, shm_perm);
174}
175
176static inline struct shmid_kernel *shm_obtain_object_check(struct ipc_namespace *ns, int id)
177{
178 struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&shm_ids(ns), id);
179
180 if (IS_ERR(ipcp))
181 return ERR_CAST(ipcp);
182
183 return container_of(ipcp, struct shmid_kernel, shm_perm);
184}
185
Nadia Derbey3e148c72007-10-18 23:40:54 -0700186/*
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700187 * shm_lock_(check_) routines are called in the paths where the rwsem
Nadia Derbey00c2bf82008-07-25 01:48:03 -0700188 * is not necessarily held.
Nadia Derbey3e148c72007-10-18 23:40:54 -0700189 */
Nadia Derbey023a5352007-10-18 23:40:51 -0700190static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191{
Davidlohr Bueso82061c52018-08-21 22:01:41 -0700192 struct kern_ipc_perm *ipcp;
Nadia Derbey03f02c72007-10-18 23:40:51 -0700193
Davidlohr Bueso82061c52018-08-21 22:01:41 -0700194 rcu_read_lock();
195 ipcp = ipc_obtain_object_idr(&shm_ids(ns), id);
196 if (IS_ERR(ipcp))
197 goto err;
198
199 ipc_lock_object(ipcp);
200 /*
201 * ipc_rmid() may have already freed the ID while ipc_lock_object()
202 * was spinning: here verify that the structure is still valid.
203 * Upon races with RMID, return -EIDRM, thus indicating that
204 * the ID points to a removed identifier.
205 */
206 if (ipc_valid_object(ipcp)) {
207 /* return a locked ipc object upon success */
208 return container_of(ipcp, struct shmid_kernel, shm_perm);
209 }
210
211 ipc_unlock_object(ipcp);
Davidlohr Bueso9c21dae2018-09-04 15:46:02 -0700212 ipcp = ERR_PTR(-EIDRM);
Davidlohr Bueso82061c52018-08-21 22:01:41 -0700213err:
214 rcu_read_unlock();
Davidlohr Buesoc5c89752015-06-30 14:58:36 -0700215 /*
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800216 * Callers of shm_lock() must validate the status of the returned ipc
Davidlohr Bueso82061c52018-08-21 22:01:41 -0700217 * object pointer and error out as appropriate.
Davidlohr Buesoc5c89752015-06-30 14:58:36 -0700218 */
Kees Cook59cf0a92018-10-05 15:51:48 -0700219 return ERR_CAST(ipcp);
Nadia Derbey023a5352007-10-18 23:40:51 -0700220}
221
Vasiliy Kulikov4c677e22011-07-29 03:56:40 +0400222static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
223{
224 rcu_read_lock();
Davidlohr Buesocf9d5d72013-07-08 16:01:11 -0700225 ipc_lock_object(&ipcp->shm_perm);
Vasiliy Kulikov4c677e22011-07-29 03:56:40 +0400226}
227
Davidlohr Bueso53dad6d2013-09-23 17:04:45 -0700228static void shm_rcu_free(struct rcu_head *head)
229{
Manfred Sprauldba4cdd2017-07-12 14:34:41 -0700230 struct kern_ipc_perm *ptr = container_of(head, struct kern_ipc_perm,
231 rcu);
232 struct shmid_kernel *shp = container_of(ptr, struct shmid_kernel,
233 shm_perm);
Eric W. Biederman7191adf2018-03-22 21:08:27 -0500234 security_shm_free(&shp->shm_perm);
Vasily Averinbc8136a2021-06-30 18:57:12 -0700235 kfree(shp);
Davidlohr Bueso53dad6d2013-09-23 17:04:45 -0700236}
237
Alexander Mikhalitsyn85b6d2462021-11-19 16:43:21 -0800238/*
239 * It has to be called with shp locked.
240 * It must be called before ipc_rmid()
241 */
242static inline void shm_clist_rm(struct shmid_kernel *shp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243{
Alexander Mikhalitsyn85b6d2462021-11-19 16:43:21 -0800244 struct task_struct *creator;
245
246 /* ensure that shm_creator does not disappear */
247 rcu_read_lock();
248
249 /*
250 * A concurrent exit_shm may do a list_del_init() as well.
251 * Just do nothing if exit_shm already did the work
252 */
253 if (!list_empty(&shp->shm_clist)) {
254 /*
255 * shp->shm_creator is guaranteed to be valid *only*
256 * if shp->shm_clist is not empty.
257 */
258 creator = shp->shm_creator;
259
260 task_lock(creator);
261 /*
262 * list_del_init() is a nop if the entry was already removed
263 * from the list.
264 */
265 list_del_init(&shp->shm_clist);
266 task_unlock(creator);
267 }
268 rcu_read_unlock();
269}
270
271static inline void shm_rmid(struct shmid_kernel *s)
272{
273 shm_clist_rm(s);
274 ipc_rmid(&shm_ids(s->ns), &s->shm_perm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275}
276
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277
Mike Kravetzb6305042022-11-14 13:00:18 -0800278static int __shm_open(struct shm_file_data *sfd)
Kirill Korotaev4e982312006-10-02 02:18:22 -0700279{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280 struct shmid_kernel *shp;
281
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800282 shp = shm_lock(sfd->ns, sfd->id);
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800283
284 if (IS_ERR(shp))
285 return PTR_ERR(shp);
286
Eric Biggers3f053172018-04-13 15:35:30 -0700287 if (shp->shm_file != sfd->file) {
288 /* ID was reused */
289 shm_unlock(shp);
290 return -EINVAL;
291 }
292
Deepa Dinamani7ff28192017-08-02 19:51:14 -0700293 shp->shm_atim = ktime_get_real_seconds();
Eric W. Biederman98f929b12018-03-23 00:29:57 -0500294 ipc_update_pid(&shp->shm_lprid, task_tgid(current));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295 shp->shm_nattch++;
296 shm_unlock(shp);
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800297 return 0;
298}
299
300/* This is called by fork, once for every shm attach. */
301static void shm_open(struct vm_area_struct *vma)
302{
Mike Kravetzb6305042022-11-14 13:00:18 -0800303 struct file *file = vma->vm_file;
304 struct shm_file_data *sfd = shm_file_data(file);
305 int err;
306
307 /* Always call underlying open if present */
308 if (sfd->vm_ops->open)
309 sfd->vm_ops->open(vma);
310
311 err = __shm_open(sfd);
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800312 /*
313 * We raced in the idr lookup or with shm_destroy().
314 * Either way, the ID is busted.
315 */
316 WARN_ON_ONCE(err);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317}
318
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319/*
320 * shm_destroy - free the struct shmid_kernel
321 *
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700322 * @ns: namespace
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323 * @shp: struct to free
324 *
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700325 * It has to be called with shp and shm_ids.rwsem (writer) locked,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 * but returns with shp unlocked and freed.
327 */
Kirill Korotaev4e982312006-10-02 02:18:22 -0700328static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329{
Greg Thelena399b292013-11-21 14:32:00 -0800330 struct file *shm_file;
331
332 shm_file = shp->shm_file;
333 shp->shm_file = NULL;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700334 ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
Alexander Mikhalitsyn85b6d2462021-11-19 16:43:21 -0800335 shm_rmid(shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336 shm_unlock(shp);
Greg Thelena399b292013-11-21 14:32:00 -0800337 if (!is_file_hugepages(shm_file))
Alexey Gladkovd7c9e992021-04-22 14:27:14 +0200338 shmem_lock(shm_file, 0, shp->mlock_ucounts);
Greg Thelena399b292013-11-21 14:32:00 -0800339 fput(shm_file);
Eric W. Biederman98f929b12018-03-23 00:29:57 -0500340 ipc_update_pid(&shp->shm_cprid, NULL);
341 ipc_update_pid(&shp->shm_lprid, NULL);
Manfred Sprauldba4cdd2017-07-12 14:34:41 -0700342 ipc_rcu_putref(&shp->shm_perm, shm_rcu_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343}
344
345/*
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700346 * shm_may_destroy - identifies whether shm segment should be destroyed now
347 *
348 * Returns true if and only if there are no active users of the segment and
349 * one of the following is true:
350 *
351 * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
352 *
353 * 2) sysctl kernel.shm_rmid_forced is set to 1.
354 */
Alexander Mikhalitsyn85b6d2462021-11-19 16:43:21 -0800355static bool shm_may_destroy(struct shmid_kernel *shp)
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700356{
357 return (shp->shm_nattch == 0) &&
Alexander Mikhalitsyn85b6d2462021-11-19 16:43:21 -0800358 (shp->ns->shm_rmid_forced ||
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700359 (shp->shm_perm.mode & SHM_DEST));
360}
361
362/*
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800363 * remove the attach descriptor vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364 * free memory for segment if it is marked destroyed.
365 * The descriptor has already been removed from the current->mm->mmap list
366 * and will later be kfree()d.
367 */
Mike Kravetzb6305042022-11-14 13:00:18 -0800368static void __shm_close(struct shm_file_data *sfd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370 struct shmid_kernel *shp;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800371 struct ipc_namespace *ns = sfd->ns;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700372
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700373 down_write(&shm_ids(ns).rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374 /* remove from the list of attaches of the shm segment */
Nadia Derbey00c2bf82008-07-25 01:48:03 -0700375 shp = shm_lock(ns, sfd->id);
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800376
377 /*
378 * We raced in the idr lookup or with shm_destroy().
379 * Either way, the ID is busted.
380 */
381 if (WARN_ON_ONCE(IS_ERR(shp)))
382 goto done; /* no-op */
383
Eric W. Biederman98f929b12018-03-23 00:29:57 -0500384 ipc_update_pid(&shp->shm_lprid, task_tgid(current));
Deepa Dinamani7ff28192017-08-02 19:51:14 -0700385 shp->shm_dtim = ktime_get_real_seconds();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386 shp->shm_nattch--;
Alexander Mikhalitsyn85b6d2462021-11-19 16:43:21 -0800387 if (shm_may_destroy(shp))
Kirill Korotaev4e982312006-10-02 02:18:22 -0700388 shm_destroy(ns, shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389 else
390 shm_unlock(shp);
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800391done:
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700392 up_write(&shm_ids(ns).rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700393}
394
Mike Kravetzb6305042022-11-14 13:00:18 -0800395static void shm_close(struct vm_area_struct *vma)
396{
397 struct file *file = vma->vm_file;
398 struct shm_file_data *sfd = shm_file_data(file);
399
400 /* Always call underlying close if present */
401 if (sfd->vm_ops->close)
402 sfd->vm_ops->close(vma);
403
404 __shm_close(sfd);
405}
406
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700407/* Called with ns->shm_ids(ns).rwsem locked */
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700408static int shm_try_destroy_orphaned(int id, void *p, void *data)
409{
410 struct ipc_namespace *ns = data;
Vasiliy Kulikov4c677e22011-07-29 03:56:40 +0400411 struct kern_ipc_perm *ipcp = p;
412 struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700413
414 /*
415 * We want to destroy segments without users and with already
416 * exit'ed originating process.
Vasiliy Kulikov4c677e22011-07-29 03:56:40 +0400417 *
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700418 * As shp->* are changed under rwsem, it's safe to skip shp locking.
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700419 */
Alexander Mikhalitsyn85b6d2462021-11-19 16:43:21 -0800420 if (!list_empty(&shp->shm_clist))
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700421 return 0;
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700422
Alexander Mikhalitsyn85b6d2462021-11-19 16:43:21 -0800423 if (shm_may_destroy(shp)) {
Vasiliy Kulikov4c677e22011-07-29 03:56:40 +0400424 shm_lock_by_ptr(shp);
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700425 shm_destroy(ns, shp);
Vasiliy Kulikov4c677e22011-07-29 03:56:40 +0400426 }
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700427 return 0;
428}
429
430void shm_destroy_orphaned(struct ipc_namespace *ns)
431{
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700432 down_write(&shm_ids(ns).rwsem);
Vasiliy Kulikov33a30ed2011-08-03 22:26:55 +0400433 if (shm_ids(ns).in_use)
Vasiliy Kulikov4c677e22011-07-29 03:56:40 +0400434 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700435 up_write(&shm_ids(ns).rwsem);
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700436}
437
Jack Miller83293c0f52014-08-08 14:23:21 -0700438/* Locking assumes this will only be called with task == current */
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700439void exit_shm(struct task_struct *task)
440{
Alexander Mikhalitsyn85b6d2462021-11-19 16:43:21 -0800441 for (;;) {
442 struct shmid_kernel *shp;
443 struct ipc_namespace *ns;
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700444
Alexander Mikhalitsyn85b6d2462021-11-19 16:43:21 -0800445 task_lock(task);
Vasiliy Kulikov298507d2011-08-03 22:28:26 +0400446
Alexander Mikhalitsyn85b6d2462021-11-19 16:43:21 -0800447 if (list_empty(&task->sysvshm.shm_clist)) {
448 task_unlock(task);
449 break;
Jack Miller83293c0f52014-08-08 14:23:21 -0700450 }
Jack Miller83293c0f52014-08-08 14:23:21 -0700451
Alexander Mikhalitsyn85b6d2462021-11-19 16:43:21 -0800452 shp = list_first_entry(&task->sysvshm.shm_clist, struct shmid_kernel,
453 shm_clist);
454
455 /*
456 * 1) Get pointer to the ipc namespace. It is worth to say
457 * that this pointer is guaranteed to be valid because
458 * shp lifetime is always shorter than namespace lifetime
459 * in which shp lives.
460 * We taken task_lock it means that shp won't be freed.
461 */
462 ns = shp->ns;
463
464 /*
465 * 2) If kernel.shm_rmid_forced is not set then only keep track of
466 * which shmids are orphaned, so that a later set of the sysctl
467 * can clean them up.
468 */
469 if (!ns->shm_rmid_forced)
470 goto unlink_continue;
471
472 /*
473 * 3) get a reference to the namespace.
474 * The refcount could be already 0. If it is 0, then
475 * the shm objects will be free by free_ipc_work().
476 */
477 ns = get_ipc_ns_not_zero(ns);
478 if (!ns) {
479unlink_continue:
480 list_del_init(&shp->shm_clist);
481 task_unlock(task);
482 continue;
483 }
484
485 /*
486 * 4) get a reference to shp.
487 * This cannot fail: shm_clist_rm() is called before
488 * ipc_rmid(), thus the refcount cannot be 0.
489 */
490 WARN_ON(!ipc_rcu_getref(&shp->shm_perm));
491
492 /*
493 * 5) unlink the shm segment from the list of segments
494 * created by current.
495 * This must be done last. After unlinking,
496 * only the refcounts obtained above prevent IPC_RMID
497 * from destroying the segment or the namespace.
498 */
499 list_del_init(&shp->shm_clist);
500
501 task_unlock(task);
502
503 /*
504 * 6) we have all references
505 * Thus lock & if needed destroy shp.
506 */
507 down_write(&shm_ids(ns).rwsem);
508 shm_lock_by_ptr(shp);
509 /*
510 * rcu_read_lock was implicitly taken in shm_lock_by_ptr, it's
511 * safe to call ipc_rcu_putref here
512 */
513 ipc_rcu_putref(&shp->shm_perm, shm_rcu_free);
514
515 if (ipc_valid_object(&shp->shm_perm)) {
516 if (shm_may_destroy(shp))
517 shm_destroy(ns, shp);
518 else
519 shm_unlock(shp);
520 } else {
521 /*
522 * Someone else deleted the shp from namespace
523 * idr/kht while we have waited.
524 * Just unlock and continue.
525 */
526 shm_unlock(shp);
527 }
528
529 up_write(&shm_ids(ns).rwsem);
530 put_ipc_ns(ns); /* paired with get_ipc_ns_not_zero */
531 }
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700532}
533
Souptick Joarder14f28f572018-06-14 15:27:55 -0700534static vm_fault_t shm_fault(struct vm_fault *vmf)
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800535{
Dave Jiang11bac802017-02-24 14:56:41 -0800536 struct file *file = vmf->vma->vm_file;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800537 struct shm_file_data *sfd = shm_file_data(file);
538
Dave Jiang11bac802017-02-24 14:56:41 -0800539 return sfd->vm_ops->fault(vmf);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800540}
541
Dmitry Safonovdd3b6142020-12-14 19:08:17 -0800542static int shm_may_split(struct vm_area_struct *vma, unsigned long addr)
Mike Kravetz3d942ee2018-03-28 16:01:01 -0700543{
544 struct file *file = vma->vm_file;
545 struct shm_file_data *sfd = shm_file_data(file);
546
Dmitry Safonovdd3b6142020-12-14 19:08:17 -0800547 if (sfd->vm_ops->may_split)
548 return sfd->vm_ops->may_split(vma, addr);
Mike Kravetz3d942ee2018-03-28 16:01:01 -0700549
550 return 0;
551}
552
Jane Chueec36362018-08-02 15:36:05 -0700553static unsigned long shm_pagesize(struct vm_area_struct *vma)
554{
555 struct file *file = vma->vm_file;
556 struct shm_file_data *sfd = shm_file_data(file);
557
558 if (sfd->vm_ops->pagesize)
559 return sfd->vm_ops->pagesize(vma);
560
561 return PAGE_SIZE;
562}
563
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800564#ifdef CONFIG_NUMA
Adrian Bunkd823e3e2007-10-16 23:26:42 -0700565static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800566{
567 struct file *file = vma->vm_file;
568 struct shm_file_data *sfd = shm_file_data(file);
569 int err = 0;
Shailesh Pandey63980c82016-12-14 15:06:10 -0800570
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800571 if (sfd->vm_ops->set_policy)
572 err = sfd->vm_ops->set_policy(vma, new);
573 return err;
574}
575
Adrian Bunkd823e3e2007-10-16 23:26:42 -0700576static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
577 unsigned long addr)
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800578{
579 struct file *file = vma->vm_file;
580 struct shm_file_data *sfd = shm_file_data(file);
581 struct mempolicy *pol = NULL;
582
583 if (sfd->vm_ops->get_policy)
584 pol = sfd->vm_ops->get_policy(vma, addr);
Lee Schermerhorn52cd3b02008-04-28 02:13:16 -0700585 else if (vma->vm_policy)
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800586 pol = vma->vm_policy;
Lee Schermerhorn52cd3b02008-04-28 02:13:16 -0700587
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800588 return pol;
589}
590#endif
591
Manfred Spraul239521f2014-01-27 17:07:04 -0800592static int shm_mmap(struct file *file, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593{
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800594 struct shm_file_data *sfd = shm_file_data(file);
David Howellsb0e15192006-01-06 00:11:42 -0800595 int ret;
596
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800597 /*
Eric Biggers3f053172018-04-13 15:35:30 -0700598 * In case of remap_file_pages() emulation, the file can represent an
599 * IPC ID that was removed, and possibly even reused by another shm
600 * segment already. Propagate this case as an error to caller.
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800601 */
Mike Kravetzb6305042022-11-14 13:00:18 -0800602 ret = __shm_open(sfd);
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800603 if (ret)
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800604 return ret;
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800605
Miklos Szeredif74ac012017-02-20 16:51:23 +0100606 ret = call_mmap(sfd->file, vma);
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800607 if (ret) {
Mike Kravetzb6305042022-11-14 13:00:18 -0800608 __shm_close(sfd);
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800609 return ret;
610 }
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800611 sfd->vm_ops = vma->vm_ops;
David Howells2e92a3b2007-07-31 00:37:24 -0700612#ifdef CONFIG_MMU
Davidlohr Buesod0edd852015-09-09 15:39:20 -0700613 WARN_ON(!sfd->vm_ops->fault);
David Howells2e92a3b2007-07-31 00:37:24 -0700614#endif
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800615 vma->vm_ops = &shm_vm_ops;
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800616 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700617}
618
Kirill Korotaev4e982312006-10-02 02:18:22 -0700619static int shm_release(struct inode *ino, struct file *file)
620{
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800621 struct shm_file_data *sfd = shm_file_data(file);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700622
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800623 put_ipc_ns(sfd->ns);
Eric Biggers3f053172018-04-13 15:35:30 -0700624 fput(sfd->file);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800625 shm_file_data(file) = NULL;
626 kfree(sfd);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700627 return 0;
628}
629
Josef Bacik02c24a82011-07-16 20:44:56 -0400630static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
Adam Litke516dffd2007-03-01 15:46:08 -0800631{
Adam Litke516dffd2007-03-01 15:46:08 -0800632 struct shm_file_data *sfd = shm_file_data(file);
Adam Litke516dffd2007-03-01 15:46:08 -0800633
Christoph Hellwig7ea80852010-05-26 17:53:25 +0200634 if (!sfd->file->f_op->fsync)
635 return -EINVAL;
Jeff Layton0f410742017-07-05 15:26:50 -0400636 return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
Adam Litke516dffd2007-03-01 15:46:08 -0800637}
638
Will Deacon7d8a4562012-06-07 14:21:13 -0700639static long shm_fallocate(struct file *file, int mode, loff_t offset,
640 loff_t len)
641{
642 struct shm_file_data *sfd = shm_file_data(file);
643
644 if (!sfd->file->f_op->fallocate)
645 return -EOPNOTSUPP;
646 return sfd->file->f_op->fallocate(file, mode, offset, len);
647}
648
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800649static unsigned long shm_get_unmapped_area(struct file *file,
650 unsigned long addr, unsigned long len, unsigned long pgoff,
651 unsigned long flags)
652{
653 struct shm_file_data *sfd = shm_file_data(file);
Shailesh Pandey63980c82016-12-14 15:06:10 -0800654
Al Viroc4caa772009-11-30 08:38:43 -0500655 return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
656 pgoff, flags);
Adam Litke516dffd2007-03-01 15:46:08 -0800657}
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800658
Arjan van de Ven9a321442007-02-12 00:55:35 -0800659static const struct file_operations shm_file_operations = {
Kirill Korotaev4e982312006-10-02 02:18:22 -0700660 .mmap = shm_mmap,
Adam Litke516dffd2007-03-01 15:46:08 -0800661 .fsync = shm_fsync,
Kirill Korotaev4e982312006-10-02 02:18:22 -0700662 .release = shm_release,
David Howellsed5e5892010-01-15 17:01:32 -0800663 .get_unmapped_area = shm_get_unmapped_area,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200664 .llseek = noop_llseek,
Will Deacon7d8a4562012-06-07 14:21:13 -0700665 .fallocate = shm_fallocate,
Al Viroc4caa772009-11-30 08:38:43 -0500666};
667
Hugh Dickinsc01d5b32016-07-26 15:26:15 -0700668/*
669 * shm_file_operations_huge is now identical to shm_file_operations,
670 * but we keep it distinct for the sake of is_file_shm_hugepages().
671 */
Al Viroc4caa772009-11-30 08:38:43 -0500672static const struct file_operations shm_file_operations_huge = {
673 .mmap = shm_mmap,
674 .fsync = shm_fsync,
675 .release = shm_release,
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800676 .get_unmapped_area = shm_get_unmapped_area,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200677 .llseek = noop_llseek,
Will Deacon7d8a4562012-06-07 14:21:13 -0700678 .fallocate = shm_fallocate,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679};
680
Yaowei Bai2954e4402016-01-20 15:01:11 -0800681bool is_file_shm_hugepages(struct file *file)
Al Viroc4caa772009-11-30 08:38:43 -0500682{
683 return file->f_op == &shm_file_operations_huge;
684}
685
Alexey Dobriyanf0f37e2f2009-09-27 22:29:37 +0400686static const struct vm_operations_struct shm_vm_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700687 .open = shm_open, /* callback for a new vm-area open */
688 .close = shm_close, /* callback for when the vm-area is released */
Nick Piggin54cb8822007-07-19 01:46:59 -0700689 .fault = shm_fault,
Dmitry Safonovdd3b6142020-12-14 19:08:17 -0800690 .may_split = shm_may_split,
Jane Chueec36362018-08-02 15:36:05 -0700691 .pagesize = shm_pagesize,
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800692#if defined(CONFIG_NUMA)
693 .set_policy = shm_set_policy,
694 .get_policy = shm_get_policy,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700695#endif
696};
697
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700698/**
699 * newseg - Create a new shared memory segment
700 * @ns: namespace
701 * @params: ptr to the structure that contains key, size and shmflg
702 *
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700703 * Called with shm_ids.rwsem held as a writer.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700704 */
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700705static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700706{
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700707 key_t key = params->key;
708 int shmflg = params->flg;
709 size_t size = params->u.size;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710 int error;
711 struct shmid_kernel *shp;
Robin Holtd69f3ba2013-04-30 19:15:54 -0700712 size_t numpages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
Manfred Spraul239521f2014-01-27 17:07:04 -0800713 struct file *file;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714 char name[13];
KOSAKI Motohiroca16d142011-05-26 19:16:19 +0900715 vm_flags_t acctflag = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700716
Kirill Korotaev4e982312006-10-02 02:18:22 -0700717 if (size < SHMMIN || size > ns->shm_ctlmax)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700718 return -EINVAL;
719
Manfred Spraul13763272014-06-06 14:37:41 -0700720 if (numpages << PAGE_SHIFT < size)
721 return -ENOSPC;
722
Manfred Spraul09c6eb12014-06-06 14:37:40 -0700723 if (ns->shm_tot + numpages < ns->shm_tot ||
724 ns->shm_tot + numpages > ns->shm_ctlall)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725 return -ENOSPC;
726
Vasily Averin18319492021-09-02 14:55:31 -0700727 shp = kmalloc(sizeof(*shp), GFP_KERNEL_ACCOUNT);
Kees Cook42e618f2017-07-12 14:35:25 -0700728 if (unlikely(!shp))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700729 return -ENOMEM;
730
731 shp->shm_perm.key = key;
Andrew Mortonb33291c2006-01-08 01:02:21 -0800732 shp->shm_perm.mode = (shmflg & S_IRWXUGO);
Alexey Gladkovd7c9e992021-04-22 14:27:14 +0200733 shp->mlock_ucounts = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700734
735 shp->shm_perm.security = NULL;
Eric W. Biederman7191adf2018-03-22 21:08:27 -0500736 error = security_shm_alloc(&shp->shm_perm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700737 if (error) {
Vasily Averinbc8136a2021-06-30 18:57:12 -0700738 kfree(shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700739 return error;
740 }
741
Manfred Spraul239521f2014-01-27 17:07:04 -0800742 sprintf(name, "SYSV%08x", key);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743 if (shmflg & SHM_HUGETLB) {
Andrew Mortonc103a4d2013-07-08 16:01:08 -0700744 struct hstate *hs;
Li Zefan091d0d52013-05-09 15:08:15 +0800745 size_t hugesize;
746
Andrew Mortonc103a4d2013-07-08 16:01:08 -0700747 hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
Li Zefan091d0d52013-05-09 15:08:15 +0800748 if (!hs) {
749 error = -EINVAL;
750 goto no_file;
751 }
752 hugesize = ALIGN(size, huge_page_size(hs));
Naoya Horiguchiaf73e4d2013-05-07 16:18:13 -0700753
Mel Gorman5a6fe122009-02-10 14:02:27 +0000754 /* hugetlb_file_setup applies strict accounting */
755 if (shmflg & SHM_NORESERVE)
756 acctflag = VM_NORESERVE;
Naoya Horiguchiaf73e4d2013-05-07 16:18:13 -0700757 file = hugetlb_file_setup(name, hugesize, acctflag,
zhangyiru83c1fd72021-11-08 18:31:27 -0800758 HUGETLB_SHMFS_INODE, (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700759 } else {
Badari Pulavartybf8f9722005-11-07 00:59:27 -0800760 /*
761 * Do not allow no accounting for OVERCOMMIT_NEVER, even
Manfred Spraul239521f2014-01-27 17:07:04 -0800762 * if it's asked for.
Badari Pulavartybf8f9722005-11-07 00:59:27 -0800763 */
764 if ((shmflg & SHM_NORESERVE) &&
765 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
Linus Torvaldsfc8744a2009-01-31 15:08:56 -0800766 acctflag = VM_NORESERVE;
Stephen Smalleye1832f22015-08-06 15:46:55 -0700767 file = shmem_kernel_file_setup(name, size, acctflag);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700768 }
769 error = PTR_ERR(file);
770 if (IS_ERR(file))
771 goto no_file;
772
Eric W. Biederman98f929b12018-03-23 00:29:57 -0500773 shp->shm_cprid = get_pid(task_tgid(current));
774 shp->shm_lprid = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775 shp->shm_atim = shp->shm_dtim = 0;
Deepa Dinamani7ff28192017-08-02 19:51:14 -0700776 shp->shm_ctim = ktime_get_real_seconds();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777 shp->shm_segsz = size;
778 shp->shm_nattch = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779 shp->shm_file = file;
Vasiliy Kulikov5774ed02011-07-29 03:55:31 +0400780 shp->shm_creator = current;
Linus Torvaldsb9a53222015-09-30 12:48:40 -0400781
Davidlohr Bueso39c96a12017-11-17 15:31:11 -0800782 /* ipc_addid() locks shp upon success. */
Manfred Spraula2642f82017-07-12 14:35:16 -0700783 error = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
784 if (error < 0)
Linus Torvaldsb9a53222015-09-30 12:48:40 -0400785 goto no_id;
Linus Torvaldsb9a53222015-09-30 12:48:40 -0400786
Alexander Mikhalitsyn85b6d2462021-11-19 16:43:21 -0800787 shp->ns = ns;
788
789 task_lock(current);
Jack Millerab602f72014-08-08 14:23:19 -0700790 list_add(&shp->shm_clist, &current->sysvshm.shm_clist);
Alexander Mikhalitsyn85b6d2462021-11-19 16:43:21 -0800791 task_unlock(current);
Davidlohr Buesodbfcd912013-07-08 16:01:09 -0700792
Badari Pulavarty30475cc2007-06-16 10:15:59 -0700793 /*
794 * shmid gets reported as "inode#" in /proc/pid/maps.
795 * proc-ps tools use this. Changing this will break them.
796 */
Al Viro496ad9a2013-01-23 17:07:38 -0500797 file_inode(file)->i_ino = shp->shm_perm.id;
Krishnakumar R551110a2005-10-29 18:16:45 -0700798
Kirill Korotaev4e982312006-10-02 02:18:22 -0700799 ns->shm_tot += numpages;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700800 error = shp->shm_perm.id;
Davidlohr Buesodbfcd912013-07-08 16:01:09 -0700801
Davidlohr Buesocf9d5d72013-07-08 16:01:11 -0700802 ipc_unlock_object(&shp->shm_perm);
Davidlohr Buesodbfcd912013-07-08 16:01:09 -0700803 rcu_read_unlock();
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700804 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700805
806no_id:
Eric W. Biederman2236d4d2018-03-28 13:38:55 -0500807 ipc_update_pid(&shp->shm_cprid, NULL);
808 ipc_update_pid(&shp->shm_lprid, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700809 fput(file);
Manfred Spraul39cfffd2018-08-21 22:01:29 -0700810 ipc_rcu_putref(&shp->shm_perm, shm_rcu_free);
811 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700812no_file:
Manfred Spraula2642f82017-07-12 14:35:16 -0700813 call_rcu(&shp->shm_perm.rcu, shm_rcu_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700814 return error;
815}
816
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700817/*
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700818 * Called with shm_ids.rwsem and ipcp locked.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700819 */
Alexey Dobriyan00898e82020-08-11 18:37:05 -0700820static int shm_more_checks(struct kern_ipc_perm *ipcp, struct ipc_params *params)
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700821{
Nadia Derbey03f02c72007-10-18 23:40:51 -0700822 struct shmid_kernel *shp;
823
824 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
825 if (shp->shm_segsz < params->u.size)
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700826 return -EINVAL;
827
828 return 0;
829}
830
Dominik Brodowski65749e02018-03-20 20:07:53 +0100831long ksys_shmget(key_t key, size_t size, int shmflg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700832{
Kirill Korotaev4e982312006-10-02 02:18:22 -0700833 struct ipc_namespace *ns;
Mathias Krauseeb66ec42014-06-06 14:37:36 -0700834 static const struct ipc_ops shm_ops = {
835 .getnew = newseg,
Eric W. Biederman50ab44b2018-03-23 23:41:55 -0500836 .associate = security_shm_associate,
Mathias Krauseeb66ec42014-06-06 14:37:36 -0700837 .more_checks = shm_more_checks,
838 };
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700839 struct ipc_params shm_params;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700840
Kirill Korotaev4e982312006-10-02 02:18:22 -0700841 ns = current->nsproxy->ipc_ns;
842
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700843 shm_params.key = key;
844 shm_params.flg = shmflg;
845 shm_params.u.size = size;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700846
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700847 return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848}
849
Dominik Brodowski65749e02018-03-20 20:07:53 +0100850SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
851{
852 return ksys_shmget(key, size, shmflg);
853}
854
Linus Torvalds1da177e2005-04-16 15:20:36 -0700855static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
856{
Manfred Spraul239521f2014-01-27 17:07:04 -0800857 switch (version) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700858 case IPC_64:
859 return copy_to_user(buf, in, sizeof(*in));
860 case IPC_OLD:
861 {
862 struct shmid_ds out;
863
Vasiliy Kulikov3af54c92010-10-30 18:22:49 +0400864 memset(&out, 0, sizeof(out));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700865 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
866 out.shm_segsz = in->shm_segsz;
867 out.shm_atime = in->shm_atime;
868 out.shm_dtime = in->shm_dtime;
869 out.shm_ctime = in->shm_ctime;
870 out.shm_cpid = in->shm_cpid;
871 out.shm_lpid = in->shm_lpid;
872 out.shm_nattch = in->shm_nattch;
873
874 return copy_to_user(buf, &out, sizeof(out));
875 }
876 default:
877 return -EINVAL;
878 }
879}
880
Pierre Peiffer016d7132008-04-29 01:00:50 -0700881static inline unsigned long
882copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700883{
Manfred Spraul239521f2014-01-27 17:07:04 -0800884 switch (version) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700885 case IPC_64:
Pierre Peiffer016d7132008-04-29 01:00:50 -0700886 if (copy_from_user(out, buf, sizeof(*out)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700887 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700888 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700889 case IPC_OLD:
890 {
891 struct shmid_ds tbuf_old;
892
893 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
894 return -EFAULT;
895
Pierre Peiffer016d7132008-04-29 01:00:50 -0700896 out->shm_perm.uid = tbuf_old.shm_perm.uid;
897 out->shm_perm.gid = tbuf_old.shm_perm.gid;
898 out->shm_perm.mode = tbuf_old.shm_perm.mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700899
900 return 0;
901 }
902 default:
903 return -EINVAL;
904 }
905}
906
907static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
908{
Manfred Spraul239521f2014-01-27 17:07:04 -0800909 switch (version) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910 case IPC_64:
911 return copy_to_user(buf, in, sizeof(*in));
912 case IPC_OLD:
913 {
914 struct shminfo out;
915
Manfred Spraul239521f2014-01-27 17:07:04 -0800916 if (in->shmmax > INT_MAX)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700917 out.shmmax = INT_MAX;
918 else
919 out.shmmax = (int)in->shmmax;
920
921 out.shmmin = in->shmmin;
922 out.shmmni = in->shmmni;
923 out.shmseg = in->shmseg;
Paul McQuade46c0a8c2014-06-06 14:37:37 -0700924 out.shmall = in->shmall;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700925
926 return copy_to_user(buf, &out, sizeof(out));
927 }
928 default:
929 return -EINVAL;
930 }
931}
932
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700933/*
Helge Dellerb7952182010-10-27 15:34:16 -0700934 * Calculate and add used RSS and swap pages of a shm.
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700935 * Called with shm_ids.rwsem held as a reader
Helge Dellerb7952182010-10-27 15:34:16 -0700936 */
937static void shm_add_rss_swap(struct shmid_kernel *shp,
938 unsigned long *rss_add, unsigned long *swp_add)
939{
940 struct inode *inode;
941
Al Viro496ad9a2013-01-23 17:07:38 -0500942 inode = file_inode(shp->shm_file);
Helge Dellerb7952182010-10-27 15:34:16 -0700943
944 if (is_file_hugepages(shp->shm_file)) {
945 struct address_space *mapping = inode->i_mapping;
946 struct hstate *h = hstate_file(shp->shm_file);
947 *rss_add += pages_per_huge_page(h) * mapping->nrpages;
948 } else {
949#ifdef CONFIG_SHMEM
950 struct shmem_inode_info *info = SHMEM_I(inode);
Shailesh Pandey63980c82016-12-14 15:06:10 -0800951
Kirill A. Shutemov4595ef82016-07-26 15:26:29 -0700952 spin_lock_irq(&info->lock);
Helge Dellerb7952182010-10-27 15:34:16 -0700953 *rss_add += inode->i_mapping->nrpages;
954 *swp_add += info->swapped;
Kirill A. Shutemov4595ef82016-07-26 15:26:29 -0700955 spin_unlock_irq(&info->lock);
Helge Dellerb7952182010-10-27 15:34:16 -0700956#else
957 *rss_add += inode->i_mapping->nrpages;
958#endif
959 }
960}
961
962/*
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700963 * Called with shm_ids.rwsem held as a reader
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700964 */
Kirill Korotaev4e982312006-10-02 02:18:22 -0700965static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
966 unsigned long *swp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700967{
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700968 int next_id;
969 int total, in_use;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700970
971 *rss = 0;
972 *swp = 0;
973
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700974 in_use = shm_ids(ns).in_use;
975
976 for (total = 0, next_id = 0; total < in_use; next_id++) {
Tony Battersbye562aeb2009-04-02 16:58:26 -0700977 struct kern_ipc_perm *ipc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700978 struct shmid_kernel *shp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700979
Tony Battersbye562aeb2009-04-02 16:58:26 -0700980 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
981 if (ipc == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700982 continue;
Tony Battersbye562aeb2009-04-02 16:58:26 -0700983 shp = container_of(ipc, struct shmid_kernel, shm_perm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700984
Helge Dellerb7952182010-10-27 15:34:16 -0700985 shm_add_rss_swap(shp, rss, swp);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700986
987 total++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700988 }
989}
990
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700991/*
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700992 * This function handles some shmctl commands which require the rwsem
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700993 * to be held in write mode.
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700994 * NOTE: no locks must be held, the rwsem is taken inside this function.
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700995 */
996static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
Al Viro9ba720c2017-07-08 20:58:06 -0400997 struct shmid64_ds *shmid64)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700998{
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700999 struct kern_ipc_perm *ipcp;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001000 struct shmid_kernel *shp;
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -07001001 int err;
1002
Davidlohr Buesod9a605e2013-09-11 14:26:24 -07001003 down_write(&shm_ids(ns).rwsem);
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -07001004 rcu_read_lock();
1005
Manfred Spraul4241c1a2018-08-21 22:01:34 -07001006 ipcp = ipcctl_obtain_check(ns, &shm_ids(ns), shmid, cmd,
Al Viro9ba720c2017-07-08 20:58:06 -04001007 &shmid64->shm_perm, 0);
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -07001008 if (IS_ERR(ipcp)) {
1009 err = PTR_ERR(ipcp);
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -07001010 goto out_unlock1;
1011 }
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -07001012
Pierre Peiffera5f75e72008-04-29 01:00:54 -07001013 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -07001014
Eric W. Biederman7191adf2018-03-22 21:08:27 -05001015 err = security_shm_shmctl(&shp->shm_perm, cmd);
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -07001016 if (err)
Davidlohr Bueso79ccf0f2013-09-11 14:26:16 -07001017 goto out_unlock1;
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -07001018
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -07001019 switch (cmd) {
1020 case IPC_RMID:
Davidlohr Bueso79ccf0f2013-09-11 14:26:16 -07001021 ipc_lock_object(&shp->shm_perm);
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -07001022 /* do_shm_rmid unlocks the ipc object and rcu */
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -07001023 do_shm_rmid(ns, ipcp);
1024 goto out_up;
1025 case IPC_SET:
Davidlohr Bueso79ccf0f2013-09-11 14:26:16 -07001026 ipc_lock_object(&shp->shm_perm);
Al Viro9ba720c2017-07-08 20:58:06 -04001027 err = ipc_update_perm(&shmid64->shm_perm, ipcp);
Eric W. Biederman1efdb692012-02-07 16:54:11 -08001028 if (err)
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -07001029 goto out_unlock0;
Deepa Dinamani7ff28192017-08-02 19:51:14 -07001030 shp->shm_ctim = ktime_get_real_seconds();
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -07001031 break;
1032 default:
1033 err = -EINVAL;
Davidlohr Bueso79ccf0f2013-09-11 14:26:16 -07001034 goto out_unlock1;
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -07001035 }
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -07001036
1037out_unlock0:
1038 ipc_unlock_object(&shp->shm_perm);
1039out_unlock1:
1040 rcu_read_unlock();
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -07001041out_up:
Davidlohr Buesod9a605e2013-09-11 14:26:24 -07001042 up_write(&shm_ids(ns).rwsem);
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -07001043 return err;
1044}
1045
Al Viro9ba720c2017-07-08 20:58:06 -04001046static int shmctl_ipc_info(struct ipc_namespace *ns,
1047 struct shminfo64 *shminfo)
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -07001048{
Al Viro9ba720c2017-07-08 20:58:06 -04001049 int err = security_shm_shmctl(NULL, IPC_INFO);
1050 if (!err) {
1051 memset(shminfo, 0, sizeof(*shminfo));
1052 shminfo->shmmni = shminfo->shmseg = ns->shm_ctlmni;
1053 shminfo->shmmax = ns->shm_ctlmax;
1054 shminfo->shmall = ns->shm_ctlall;
1055 shminfo->shmmin = SHMMIN;
Davidlohr Buesod9a605e2013-09-11 14:26:24 -07001056 down_read(&shm_ids(ns).rwsem);
Manfred Spraul27c331a2018-08-21 22:02:00 -07001057 err = ipc_get_maxidx(&shm_ids(ns));
Davidlohr Buesod9a605e2013-09-11 14:26:24 -07001058 up_read(&shm_ids(ns).rwsem);
Manfred Spraul239521f2014-01-27 17:07:04 -08001059 if (err < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001060 err = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001061 }
Al Viro9ba720c2017-07-08 20:58:06 -04001062 return err;
1063}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001064
Al Viro9ba720c2017-07-08 20:58:06 -04001065static int shmctl_shm_info(struct ipc_namespace *ns,
1066 struct shm_info *shm_info)
1067{
1068 int err = security_shm_shmctl(NULL, SHM_INFO);
1069 if (!err) {
1070 memset(shm_info, 0, sizeof(*shm_info));
Davidlohr Buesod9a605e2013-09-11 14:26:24 -07001071 down_read(&shm_ids(ns).rwsem);
Al Viro9ba720c2017-07-08 20:58:06 -04001072 shm_info->used_ids = shm_ids(ns).in_use;
1073 shm_get_stat(ns, &shm_info->shm_rss, &shm_info->shm_swp);
1074 shm_info->shm_tot = ns->shm_tot;
1075 shm_info->swap_attempts = 0;
1076 shm_info->swap_successes = 0;
Manfred Spraul27c331a2018-08-21 22:02:00 -07001077 err = ipc_get_maxidx(&shm_ids(ns));
Davidlohr Buesod9a605e2013-09-11 14:26:24 -07001078 up_read(&shm_ids(ns).rwsem);
Al Viro9ba720c2017-07-08 20:58:06 -04001079 if (err < 0)
1080 err = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001081 }
Al Viro9ba720c2017-07-08 20:58:06 -04001082 return err;
1083}
Nadia Derbey023a5352007-10-18 23:40:51 -07001084
Al Viro9ba720c2017-07-08 20:58:06 -04001085static int shmctl_stat(struct ipc_namespace *ns, int shmid,
1086 int cmd, struct shmid64_ds *tbuf)
1087{
1088 struct shmid_kernel *shp;
Al Viro9ba720c2017-07-08 20:58:06 -04001089 int err;
Davidlohr Buesoc97cb9c2013-09-11 14:26:20 -07001090
Philippe Mikoyan87ad4b02018-02-06 15:40:49 -08001091 memset(tbuf, 0, sizeof(*tbuf));
1092
Al Viro9ba720c2017-07-08 20:58:06 -04001093 rcu_read_lock();
Davidlohr Buesoc21a6972018-04-10 16:35:23 -07001094 if (cmd == SHM_STAT || cmd == SHM_STAT_ANY) {
Al Viro9ba720c2017-07-08 20:58:06 -04001095 shp = shm_obtain_object(ns, shmid);
1096 if (IS_ERR(shp)) {
1097 err = PTR_ERR(shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001098 goto out_unlock;
Al Viro9ba720c2017-07-08 20:58:06 -04001099 }
Davidlohr Buesoc21a6972018-04-10 16:35:23 -07001100 } else { /* IPC_STAT */
Al Viro9ba720c2017-07-08 20:58:06 -04001101 shp = shm_obtain_object_check(ns, shmid);
1102 if (IS_ERR(shp)) {
1103 err = PTR_ERR(shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001104 goto out_unlock;
Al Viro9ba720c2017-07-08 20:58:06 -04001105 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001106 }
Al Viro9ba720c2017-07-08 20:58:06 -04001107
Davidlohr Buesoc21a6972018-04-10 16:35:23 -07001108 /*
1109 * Semantically SHM_STAT_ANY ought to be identical to
1110 * that functionality provided by the /proc/sysvipc/
1111 * interface. As such, only audit these calls and
1112 * do not do traditional S_IRUGO permission checks on
1113 * the ipc object.
1114 */
1115 if (cmd == SHM_STAT_ANY)
1116 audit_ipc_obj(&shp->shm_perm);
1117 else {
1118 err = -EACCES;
1119 if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
1120 goto out_unlock;
1121 }
Al Viro9ba720c2017-07-08 20:58:06 -04001122
Eric W. Biederman7191adf2018-03-22 21:08:27 -05001123 err = security_shm_shmctl(&shp->shm_perm, cmd);
Al Viro9ba720c2017-07-08 20:58:06 -04001124 if (err)
1125 goto out_unlock;
1126
Philippe Mikoyan87ad4b02018-02-06 15:40:49 -08001127 ipc_lock_object(&shp->shm_perm);
1128
1129 if (!ipc_valid_object(&shp->shm_perm)) {
1130 ipc_unlock_object(&shp->shm_perm);
1131 err = -EIDRM;
1132 goto out_unlock;
1133 }
1134
Al Viro9ba720c2017-07-08 20:58:06 -04001135 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf->shm_perm);
1136 tbuf->shm_segsz = shp->shm_segsz;
1137 tbuf->shm_atime = shp->shm_atim;
1138 tbuf->shm_dtime = shp->shm_dtim;
1139 tbuf->shm_ctime = shp->shm_ctim;
Arnd Bergmannc2ab9752015-04-28 21:39:50 +02001140#ifndef CONFIG_64BIT
1141 tbuf->shm_atime_high = shp->shm_atim >> 32;
1142 tbuf->shm_dtime_high = shp->shm_dtim >> 32;
1143 tbuf->shm_ctime_high = shp->shm_ctim >> 32;
1144#endif
Eric W. Biederman98f929b12018-03-23 00:29:57 -05001145 tbuf->shm_cpid = pid_vnr(shp->shm_cprid);
1146 tbuf->shm_lpid = pid_vnr(shp->shm_lprid);
Al Viro9ba720c2017-07-08 20:58:06 -04001147 tbuf->shm_nattch = shp->shm_nattch;
Philippe Mikoyan87ad4b02018-02-06 15:40:49 -08001148
Manfred Spraul615c9992018-08-21 22:01:21 -07001149 if (cmd == IPC_STAT) {
1150 /*
1151 * As defined in SUS:
1152 * Return 0 on success
1153 */
1154 err = 0;
1155 } else {
1156 /*
1157 * SHM_STAT and SHM_STAT_ANY (both Linux specific)
1158 * Return the full id, including the sequence number
1159 */
1160 err = shp->shm_perm.id;
1161 }
Davidlohr Bueso68eccc12013-09-11 14:26:18 -07001162
Manfred Spraul615c9992018-08-21 22:01:21 -07001163 ipc_unlock_object(&shp->shm_perm);
Davidlohr Bueso68eccc12013-09-11 14:26:18 -07001164out_unlock:
Davidlohr Buesoc97cb9c2013-09-11 14:26:20 -07001165 rcu_read_unlock();
Al Viro9ba720c2017-07-08 20:58:06 -04001166 return err;
1167}
1168
1169static int shmctl_do_lock(struct ipc_namespace *ns, int shmid, int cmd)
1170{
1171 struct shmid_kernel *shp;
1172 struct file *shm_file;
1173 int err;
1174
1175 rcu_read_lock();
1176 shp = shm_obtain_object_check(ns, shmid);
1177 if (IS_ERR(shp)) {
1178 err = PTR_ERR(shp);
1179 goto out_unlock1;
1180 }
1181
1182 audit_ipc_obj(&(shp->shm_perm));
Eric W. Biederman7191adf2018-03-22 21:08:27 -05001183 err = security_shm_shmctl(&shp->shm_perm, cmd);
Al Viro9ba720c2017-07-08 20:58:06 -04001184 if (err)
1185 goto out_unlock1;
1186
1187 ipc_lock_object(&shp->shm_perm);
1188
1189 /* check if shm_destroy() is tearing down shp */
1190 if (!ipc_valid_object(&shp->shm_perm)) {
1191 err = -EIDRM;
1192 goto out_unlock0;
1193 }
1194
1195 if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
1196 kuid_t euid = current_euid();
1197
1198 if (!uid_eq(euid, shp->shm_perm.uid) &&
1199 !uid_eq(euid, shp->shm_perm.cuid)) {
1200 err = -EPERM;
1201 goto out_unlock0;
1202 }
1203 if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) {
1204 err = -EPERM;
1205 goto out_unlock0;
1206 }
1207 }
1208
1209 shm_file = shp->shm_file;
1210 if (is_file_hugepages(shm_file))
1211 goto out_unlock0;
1212
1213 if (cmd == SHM_LOCK) {
Alexey Gladkovd7c9e992021-04-22 14:27:14 +02001214 struct ucounts *ucounts = current_ucounts();
Al Viro9ba720c2017-07-08 20:58:06 -04001215
Alexey Gladkovd7c9e992021-04-22 14:27:14 +02001216 err = shmem_lock(shm_file, 1, ucounts);
Al Viro9ba720c2017-07-08 20:58:06 -04001217 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
1218 shp->shm_perm.mode |= SHM_LOCKED;
Alexey Gladkovd7c9e992021-04-22 14:27:14 +02001219 shp->mlock_ucounts = ucounts;
Al Viro9ba720c2017-07-08 20:58:06 -04001220 }
1221 goto out_unlock0;
1222 }
1223
1224 /* SHM_UNLOCK */
1225 if (!(shp->shm_perm.mode & SHM_LOCKED))
1226 goto out_unlock0;
Alexey Gladkovd7c9e992021-04-22 14:27:14 +02001227 shmem_lock(shm_file, 0, shp->mlock_ucounts);
Al Viro9ba720c2017-07-08 20:58:06 -04001228 shp->shm_perm.mode &= ~SHM_LOCKED;
Alexey Gladkovd7c9e992021-04-22 14:27:14 +02001229 shp->mlock_ucounts = NULL;
Al Viro9ba720c2017-07-08 20:58:06 -04001230 get_file(shm_file);
1231 ipc_unlock_object(&shp->shm_perm);
1232 rcu_read_unlock();
1233 shmem_unlock_mapping(shm_file->f_mapping);
1234
1235 fput(shm_file);
1236 return err;
1237
1238out_unlock0:
1239 ipc_unlock_object(&shp->shm_perm);
1240out_unlock1:
1241 rcu_read_unlock();
Davidlohr Bueso68eccc12013-09-11 14:26:18 -07001242 return err;
1243}
1244
Arnd Bergmann275f2212018-12-31 22:22:40 +01001245static long ksys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf, int version)
Davidlohr Bueso68eccc12013-09-11 14:26:18 -07001246{
Arnd Bergmann275f2212018-12-31 22:22:40 +01001247 int err;
Davidlohr Bueso68eccc12013-09-11 14:26:18 -07001248 struct ipc_namespace *ns;
Al Viro553f7702017-07-08 22:52:47 -04001249 struct shmid64_ds sem64;
Davidlohr Bueso68eccc12013-09-11 14:26:18 -07001250
Davidlohr Bueso2caacaa2013-09-11 14:26:21 -07001251 if (cmd < 0 || shmid < 0)
1252 return -EINVAL;
Davidlohr Bueso68eccc12013-09-11 14:26:18 -07001253
Davidlohr Bueso68eccc12013-09-11 14:26:18 -07001254 ns = current->nsproxy->ipc_ns;
1255
1256 switch (cmd) {
Al Viro9ba720c2017-07-08 20:58:06 -04001257 case IPC_INFO: {
1258 struct shminfo64 shminfo;
1259 err = shmctl_ipc_info(ns, &shminfo);
1260 if (err < 0)
1261 return err;
1262 if (copy_shminfo_to_user(buf, &shminfo, version))
1263 err = -EFAULT;
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -07001264 return err;
Davidlohr Bueso2caacaa2013-09-11 14:26:21 -07001265 }
Al Viro9ba720c2017-07-08 20:58:06 -04001266 case SHM_INFO: {
1267 struct shm_info shm_info;
1268 err = shmctl_shm_info(ns, &shm_info);
1269 if (err < 0)
1270 return err;
1271 if (copy_to_user(buf, &shm_info, sizeof(shm_info)))
1272 err = -EFAULT;
1273 return err;
1274 }
1275 case SHM_STAT:
Davidlohr Buesoc21a6972018-04-10 16:35:23 -07001276 case SHM_STAT_ANY:
Al Viro9ba720c2017-07-08 20:58:06 -04001277 case IPC_STAT: {
Al Viro553f7702017-07-08 22:52:47 -04001278 err = shmctl_stat(ns, shmid, cmd, &sem64);
Al Viro9ba720c2017-07-08 20:58:06 -04001279 if (err < 0)
1280 return err;
Al Viro553f7702017-07-08 22:52:47 -04001281 if (copy_shmid_to_user(buf, &sem64, version))
Al Viro9ba720c2017-07-08 20:58:06 -04001282 err = -EFAULT;
1283 return err;
1284 }
1285 case IPC_SET:
Al Viro553f7702017-07-08 22:52:47 -04001286 if (copy_shmid_from_user(&sem64, buf, version))
Al Viro9ba720c2017-07-08 20:58:06 -04001287 return -EFAULT;
Gustavo A. R. Silvadf561f662020-08-23 17:36:59 -05001288 fallthrough;
Al Viro9ba720c2017-07-08 20:58:06 -04001289 case IPC_RMID:
Al Viro553f7702017-07-08 22:52:47 -04001290 return shmctl_down(ns, shmid, cmd, &sem64);
Al Viro9ba720c2017-07-08 20:58:06 -04001291 case SHM_LOCK:
1292 case SHM_UNLOCK:
1293 return shmctl_do_lock(ns, shmid, cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001294 default:
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -07001295 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001296 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001297}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001298
Dominik Brodowskic84d0792018-03-20 20:12:33 +01001299SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
1300{
Arnd Bergmann275f2212018-12-31 22:22:40 +01001301 return ksys_shmctl(shmid, cmd, buf, IPC_64);
Dominik Brodowskic84d0792018-03-20 20:12:33 +01001302}
1303
Arnd Bergmann275f2212018-12-31 22:22:40 +01001304#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
1305long ksys_old_shmctl(int shmid, int cmd, struct shmid_ds __user *buf)
1306{
1307 int version = ipc_parse_version(&cmd);
1308
1309 return ksys_shmctl(shmid, cmd, buf, version);
1310}
1311
1312SYSCALL_DEFINE3(old_shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
1313{
1314 return ksys_old_shmctl(shmid, cmd, buf);
1315}
1316#endif
1317
Al Viro553f7702017-07-08 22:52:47 -04001318#ifdef CONFIG_COMPAT
1319
1320struct compat_shmid_ds {
1321 struct compat_ipc_perm shm_perm;
1322 int shm_segsz;
Arnd Bergmann9afc5ee2018-07-13 12:52:28 +02001323 old_time32_t shm_atime;
1324 old_time32_t shm_dtime;
1325 old_time32_t shm_ctime;
Al Viro553f7702017-07-08 22:52:47 -04001326 compat_ipc_pid_t shm_cpid;
1327 compat_ipc_pid_t shm_lpid;
1328 unsigned short shm_nattch;
1329 unsigned short shm_unused;
1330 compat_uptr_t shm_unused2;
1331 compat_uptr_t shm_unused3;
1332};
1333
1334struct compat_shminfo64 {
1335 compat_ulong_t shmmax;
1336 compat_ulong_t shmmin;
1337 compat_ulong_t shmmni;
1338 compat_ulong_t shmseg;
1339 compat_ulong_t shmall;
1340 compat_ulong_t __unused1;
1341 compat_ulong_t __unused2;
1342 compat_ulong_t __unused3;
1343 compat_ulong_t __unused4;
1344};
1345
1346struct compat_shm_info {
1347 compat_int_t used_ids;
1348 compat_ulong_t shm_tot, shm_rss, shm_swp;
1349 compat_ulong_t swap_attempts, swap_successes;
1350};
1351
1352static int copy_compat_shminfo_to_user(void __user *buf, struct shminfo64 *in,
1353 int version)
1354{
1355 if (in->shmmax > INT_MAX)
1356 in->shmmax = INT_MAX;
1357 if (version == IPC_64) {
1358 struct compat_shminfo64 info;
1359 memset(&info, 0, sizeof(info));
1360 info.shmmax = in->shmmax;
1361 info.shmmin = in->shmmin;
1362 info.shmmni = in->shmmni;
1363 info.shmseg = in->shmseg;
1364 info.shmall = in->shmall;
1365 return copy_to_user(buf, &info, sizeof(info));
1366 } else {
1367 struct shminfo info;
1368 memset(&info, 0, sizeof(info));
1369 info.shmmax = in->shmmax;
1370 info.shmmin = in->shmmin;
1371 info.shmmni = in->shmmni;
1372 info.shmseg = in->shmseg;
1373 info.shmall = in->shmall;
1374 return copy_to_user(buf, &info, sizeof(info));
1375 }
1376}
1377
1378static int put_compat_shm_info(struct shm_info *ip,
1379 struct compat_shm_info __user *uip)
1380{
1381 struct compat_shm_info info;
1382
1383 memset(&info, 0, sizeof(info));
1384 info.used_ids = ip->used_ids;
1385 info.shm_tot = ip->shm_tot;
1386 info.shm_rss = ip->shm_rss;
1387 info.shm_swp = ip->shm_swp;
1388 info.swap_attempts = ip->swap_attempts;
1389 info.swap_successes = ip->swap_successes;
Al Virob776e4b2017-09-25 20:38:45 -04001390 return copy_to_user(uip, &info, sizeof(info));
Al Viro553f7702017-07-08 22:52:47 -04001391}
1392
1393static int copy_compat_shmid_to_user(void __user *buf, struct shmid64_ds *in,
1394 int version)
1395{
1396 if (version == IPC_64) {
1397 struct compat_shmid64_ds v;
1398 memset(&v, 0, sizeof(v));
Al Viro28327fa2017-07-09 10:10:32 -04001399 to_compat_ipc64_perm(&v.shm_perm, &in->shm_perm);
Arnd Bergmannc2ab9752015-04-28 21:39:50 +02001400 v.shm_atime = lower_32_bits(in->shm_atime);
1401 v.shm_atime_high = upper_32_bits(in->shm_atime);
1402 v.shm_dtime = lower_32_bits(in->shm_dtime);
1403 v.shm_dtime_high = upper_32_bits(in->shm_dtime);
1404 v.shm_ctime = lower_32_bits(in->shm_ctime);
1405 v.shm_ctime_high = upper_32_bits(in->shm_ctime);
Al Viro553f7702017-07-08 22:52:47 -04001406 v.shm_segsz = in->shm_segsz;
1407 v.shm_nattch = in->shm_nattch;
1408 v.shm_cpid = in->shm_cpid;
1409 v.shm_lpid = in->shm_lpid;
1410 return copy_to_user(buf, &v, sizeof(v));
1411 } else {
1412 struct compat_shmid_ds v;
1413 memset(&v, 0, sizeof(v));
Al Viro28327fa2017-07-09 10:10:32 -04001414 to_compat_ipc_perm(&v.shm_perm, &in->shm_perm);
Al Viro553f7702017-07-08 22:52:47 -04001415 v.shm_perm.key = in->shm_perm.key;
Al Viro553f7702017-07-08 22:52:47 -04001416 v.shm_atime = in->shm_atime;
1417 v.shm_dtime = in->shm_dtime;
1418 v.shm_ctime = in->shm_ctime;
1419 v.shm_segsz = in->shm_segsz;
1420 v.shm_nattch = in->shm_nattch;
1421 v.shm_cpid = in->shm_cpid;
1422 v.shm_lpid = in->shm_lpid;
1423 return copy_to_user(buf, &v, sizeof(v));
1424 }
1425}
1426
1427static int copy_compat_shmid_from_user(struct shmid64_ds *out, void __user *buf,
1428 int version)
1429{
1430 memset(out, 0, sizeof(*out));
1431 if (version == IPC_64) {
Linus Torvalds6aa211e2017-09-25 18:37:28 -07001432 struct compat_shmid64_ds __user *p = buf;
Al Viro28327fa2017-07-09 10:10:32 -04001433 return get_compat_ipc64_perm(&out->shm_perm, &p->shm_perm);
Al Viro553f7702017-07-08 22:52:47 -04001434 } else {
Linus Torvalds6aa211e2017-09-25 18:37:28 -07001435 struct compat_shmid_ds __user *p = buf;
Al Viro28327fa2017-07-09 10:10:32 -04001436 return get_compat_ipc_perm(&out->shm_perm, &p->shm_perm);
Al Viro553f7702017-07-08 22:52:47 -04001437 }
Al Viro553f7702017-07-08 22:52:47 -04001438}
1439
Jason Yan1cd377b2020-04-06 20:12:56 -07001440static long compat_ksys_shmctl(int shmid, int cmd, void __user *uptr, int version)
Al Viro553f7702017-07-08 22:52:47 -04001441{
1442 struct ipc_namespace *ns;
1443 struct shmid64_ds sem64;
Al Viro553f7702017-07-08 22:52:47 -04001444 int err;
1445
1446 ns = current->nsproxy->ipc_ns;
1447
1448 if (cmd < 0 || shmid < 0)
1449 return -EINVAL;
1450
1451 switch (cmd) {
1452 case IPC_INFO: {
1453 struct shminfo64 shminfo;
1454 err = shmctl_ipc_info(ns, &shminfo);
1455 if (err < 0)
1456 return err;
1457 if (copy_compat_shminfo_to_user(uptr, &shminfo, version))
1458 err = -EFAULT;
1459 return err;
1460 }
1461 case SHM_INFO: {
1462 struct shm_info shm_info;
1463 err = shmctl_shm_info(ns, &shm_info);
1464 if (err < 0)
1465 return err;
1466 if (put_compat_shm_info(&shm_info, uptr))
1467 err = -EFAULT;
1468 return err;
1469 }
1470 case IPC_STAT:
Davidlohr Buesoc21a6972018-04-10 16:35:23 -07001471 case SHM_STAT_ANY:
Al Viro553f7702017-07-08 22:52:47 -04001472 case SHM_STAT:
1473 err = shmctl_stat(ns, shmid, cmd, &sem64);
1474 if (err < 0)
1475 return err;
Will Deacon58aff0a2017-09-18 17:47:38 +01001476 if (copy_compat_shmid_to_user(uptr, &sem64, version))
Al Viro553f7702017-07-08 22:52:47 -04001477 err = -EFAULT;
1478 return err;
1479
1480 case IPC_SET:
1481 if (copy_compat_shmid_from_user(&sem64, uptr, version))
1482 return -EFAULT;
Gustavo A. R. Silvadf561f662020-08-23 17:36:59 -05001483 fallthrough;
Al Viro553f7702017-07-08 22:52:47 -04001484 case IPC_RMID:
1485 return shmctl_down(ns, shmid, cmd, &sem64);
1486 case SHM_LOCK:
1487 case SHM_UNLOCK:
1488 return shmctl_do_lock(ns, shmid, cmd);
Al Viro553f7702017-07-08 22:52:47 -04001489 default:
1490 return -EINVAL;
1491 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001492 return err;
1493}
Dominik Brodowskic84d0792018-03-20 20:12:33 +01001494
1495COMPAT_SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, void __user *, uptr)
1496{
Arnd Bergmann275f2212018-12-31 22:22:40 +01001497 return compat_ksys_shmctl(shmid, cmd, uptr, IPC_64);
Dominik Brodowskic84d0792018-03-20 20:12:33 +01001498}
Arnd Bergmann275f2212018-12-31 22:22:40 +01001499
1500#ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION
1501long compat_ksys_old_shmctl(int shmid, int cmd, void __user *uptr)
1502{
1503 int version = compat_ipc_parse_version(&cmd);
1504
1505 return compat_ksys_shmctl(shmid, cmd, uptr, version);
1506}
1507
1508COMPAT_SYSCALL_DEFINE3(old_shmctl, int, shmid, int, cmd, void __user *, uptr)
1509{
1510 return compat_ksys_old_shmctl(shmid, cmd, uptr);
1511}
1512#endif
Al Viro553f7702017-07-08 22:52:47 -04001513#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07001514
1515/*
1516 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
1517 *
1518 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
1519 * "raddr" thing points to kernel space, and there has to be a wrapper around
1520 * this.
1521 */
Davidlohr Bueso95e91b82017-02-27 14:28:24 -08001522long do_shmat(int shmid, char __user *shmaddr, int shmflg,
1523 ulong *raddr, unsigned long shmlba)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001524{
1525 struct shmid_kernel *shp;
Davidlohr Buesof0cb8802017-05-08 15:57:03 -07001526 unsigned long addr = (unsigned long)shmaddr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001527 unsigned long size;
Al Viro4f089ac2018-06-17 12:24:00 -04001528 struct file *file, *base;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001529 int err;
Davidlohr Buesof0cb8802017-05-08 15:57:03 -07001530 unsigned long flags = MAP_SHARED;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001531 unsigned long prot;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001532 int acc_mode;
Kirill Korotaev4e982312006-10-02 02:18:22 -07001533 struct ipc_namespace *ns;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001534 struct shm_file_data *sfd;
Al Viroc9c554f2018-07-11 14:19:04 -04001535 int f_flags;
Michel Lespinasse41badc12013-02-22 16:32:47 -08001536 unsigned long populate = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001537
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001538 err = -EINVAL;
1539 if (shmid < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001540 goto out;
Davidlohr Buesof0cb8802017-05-08 15:57:03 -07001541
1542 if (addr) {
Will Deacon079a96a2012-07-30 14:42:38 -07001543 if (addr & (shmlba - 1)) {
Davidlohr Bueso8f89c002018-05-25 14:47:30 -07001544 if (shmflg & SHM_RND) {
Davidlohr Buesoa73ab242018-05-25 14:47:27 -07001545 addr &= ~(shmlba - 1); /* round down */
Davidlohr Bueso8f89c002018-05-25 14:47:30 -07001546
1547 /*
1548 * Ensure that the round-down is non-nil
1549 * when remapping. This can happen for
1550 * cases when addr < shmlba.
1551 */
1552 if (!addr && (shmflg & SHM_REMAP))
1553 goto out;
1554 } else
Linus Torvalds1da177e2005-04-16 15:20:36 -07001555#ifndef __ARCH_FORCE_SHMLBA
1556 if (addr & ~PAGE_MASK)
1557#endif
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001558 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001559 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001560
Davidlohr Buesof0cb8802017-05-08 15:57:03 -07001561 flags |= MAP_FIXED;
1562 } else if ((shmflg & SHM_REMAP))
1563 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001564
1565 if (shmflg & SHM_RDONLY) {
1566 prot = PROT_READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001567 acc_mode = S_IRUGO;
Al Viroc9c554f2018-07-11 14:19:04 -04001568 f_flags = O_RDONLY;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001569 } else {
1570 prot = PROT_READ | PROT_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001571 acc_mode = S_IRUGO | S_IWUGO;
Al Viroc9c554f2018-07-11 14:19:04 -04001572 f_flags = O_RDWR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001573 }
1574 if (shmflg & SHM_EXEC) {
1575 prot |= PROT_EXEC;
1576 acc_mode |= S_IXUGO;
1577 }
1578
1579 /*
1580 * We cannot rely on the fs check since SYSV IPC does have an
1581 * additional creator id...
1582 */
Kirill Korotaev4e982312006-10-02 02:18:22 -07001583 ns = current->nsproxy->ipc_ns;
Davidlohr Buesoc2c737a2013-09-11 14:26:23 -07001584 rcu_read_lock();
1585 shp = shm_obtain_object_check(ns, shmid);
Nadia Derbey023a5352007-10-18 23:40:51 -07001586 if (IS_ERR(shp)) {
1587 err = PTR_ERR(shp);
Davidlohr Buesoc2c737a2013-09-11 14:26:23 -07001588 goto out_unlock;
Nadia Derbey023a5352007-10-18 23:40:51 -07001589 }
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001590
1591 err = -EACCES;
Serge E. Hallynb0e77592011-03-23 16:43:24 -07001592 if (ipcperms(ns, &shp->shm_perm, acc_mode))
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001593 goto out_unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001594
Eric W. Biederman7191adf2018-03-22 21:08:27 -05001595 err = security_shm_shmat(&shp->shm_perm, shmaddr, shmflg);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001596 if (err)
1597 goto out_unlock;
1598
Davidlohr Buesoc2c737a2013-09-11 14:26:23 -07001599 ipc_lock_object(&shp->shm_perm);
Greg Thelena399b292013-11-21 14:32:00 -08001600
1601 /* check if shm_destroy() is tearing down shp */
Rafael Aquini0f3d2b02014-01-27 17:07:01 -08001602 if (!ipc_valid_object(&shp->shm_perm)) {
Greg Thelena399b292013-11-21 14:32:00 -08001603 ipc_unlock_object(&shp->shm_perm);
1604 err = -EIDRM;
1605 goto out_unlock;
1606 }
1607
Eric Biggers3f053172018-04-13 15:35:30 -07001608 /*
1609 * We need to take a reference to the real shm file to prevent the
1610 * pointer from becoming stale in cases where the lifetime of the outer
1611 * file extends beyond that of the shm segment. It's not usually
1612 * possible, but it can happen during remap_file_pages() emulation as
1613 * that unmaps the memory, then does ->mmap() via file reference only.
1614 * We'll deny the ->mmap() if the shm segment was since removed, but to
1615 * detect shm ID reuse we need to compare the file pointers.
1616 */
Al Viro4f089ac2018-06-17 12:24:00 -04001617 base = get_file(shp->shm_file);
1618 shp->shm_nattch++;
1619 size = i_size_read(file_inode(base));
1620 ipc_unlock_object(&shp->shm_perm);
1621 rcu_read_unlock();
1622
1623 err = -ENOMEM;
1624 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
1625 if (!sfd) {
1626 fput(base);
1627 goto out_nattch;
1628 }
1629
1630 file = alloc_file_clone(base, f_flags,
1631 is_file_hugepages(base) ?
1632 &shm_file_operations_huge :
1633 &shm_file_operations);
1634 err = PTR_ERR(file);
1635 if (IS_ERR(file)) {
1636 kfree(sfd);
1637 fput(base);
1638 goto out_nattch;
1639 }
1640
1641 sfd->id = shp->shm_perm.id;
1642 sfd->ns = get_ipc_ns(ns);
1643 sfd->file = base;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001644 sfd->vm_ops = NULL;
Al Viro4f089ac2018-06-17 12:24:00 -04001645 file->private_data = sfd;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001646
Al Viro8b3ec682012-05-30 17:11:23 -04001647 err = security_mmap_file(file, prot, flags);
1648 if (err)
1649 goto out_fput;
1650
Michel Lespinassed8ed45c2020-06-08 21:33:25 -07001651 if (mmap_write_lock_killable(current->mm)) {
Michal Hocko91f4f942016-05-23 16:25:51 -07001652 err = -EINTR;
1653 goto out_fput;
1654 }
1655
Linus Torvalds1da177e2005-04-16 15:20:36 -07001656 if (addr && !(shmflg & SHM_REMAP)) {
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001657 err = -EINVAL;
Manfred Spraul247a8ce2014-06-06 14:37:38 -07001658 if (addr + size < addr)
1659 goto invalid;
1660
Linus Torvalds1da177e2005-04-16 15:20:36 -07001661 if (find_vma_intersection(current->mm, addr, addr + size))
1662 goto invalid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001663 }
Davidlohr Buesof42569b2013-09-11 14:26:22 -07001664
Peter Collingbourne45e55302020-08-06 23:23:37 -07001665 addr = do_mmap(file, addr, size, prot, flags, 0, &populate, NULL);
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001666 *raddr = addr;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001667 err = 0;
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001668 if (IS_ERR_VALUE(addr))
1669 err = (long)addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001670invalid:
Michel Lespinassed8ed45c2020-06-08 21:33:25 -07001671 mmap_write_unlock(current->mm);
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001672 if (populate)
Michel Lespinasse41badc12013-02-22 16:32:47 -08001673 mm_populate(addr, populate);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001674
Al Viro8b3ec682012-05-30 17:11:23 -04001675out_fput:
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001676 fput(file);
1677
1678out_nattch:
Davidlohr Buesod9a605e2013-09-11 14:26:24 -07001679 down_write(&shm_ids(ns).rwsem);
Nadia Derbey00c2bf82008-07-25 01:48:03 -07001680 shp = shm_lock(ns, shmid);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001681 shp->shm_nattch--;
Alexander Mikhalitsyn85b6d2462021-11-19 16:43:21 -08001682
1683 if (shm_may_destroy(shp))
Kirill Korotaev4e982312006-10-02 02:18:22 -07001684 shm_destroy(ns, shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001685 else
1686 shm_unlock(shp);
Davidlohr Buesod9a605e2013-09-11 14:26:24 -07001687 up_write(&shm_ids(ns).rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001688 return err;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001689
1690out_unlock:
Davidlohr Buesoc2c737a2013-09-11 14:26:23 -07001691 rcu_read_unlock();
Davidlohr Buesof42569b2013-09-11 14:26:22 -07001692out:
1693 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001694}
1695
Heiko Carstensd5460c92009-01-14 14:14:27 +01001696SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
Stephen Rothwell7d87e14c2005-05-01 08:59:12 -07001697{
1698 unsigned long ret;
1699 long err;
1700
Will Deacon079a96a2012-07-30 14:42:38 -07001701 err = do_shmat(shmid, shmaddr, shmflg, &ret, SHMLBA);
Stephen Rothwell7d87e14c2005-05-01 08:59:12 -07001702 if (err)
1703 return err;
1704 force_successful_syscall_return();
1705 return (long)ret;
1706}
1707
Al Viroa78ee9e2017-07-09 10:38:28 -04001708#ifdef CONFIG_COMPAT
1709
1710#ifndef COMPAT_SHMLBA
1711#define COMPAT_SHMLBA SHMLBA
1712#endif
1713
1714COMPAT_SYSCALL_DEFINE3(shmat, int, shmid, compat_uptr_t, shmaddr, int, shmflg)
1715{
1716 unsigned long ret;
1717 long err;
1718
1719 err = do_shmat(shmid, compat_ptr(shmaddr), shmflg, &ret, COMPAT_SHMLBA);
1720 if (err)
1721 return err;
1722 force_successful_syscall_return();
1723 return (long)ret;
1724}
1725#endif
1726
Linus Torvalds1da177e2005-04-16 15:20:36 -07001727/*
1728 * detach and kill segment if marked destroyed.
1729 * The work is done in shm_close.
1730 */
Dominik Brodowskida1e27442018-03-20 20:09:48 +01001731long ksys_shmdt(char __user *shmaddr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001732{
1733 struct mm_struct *mm = current->mm;
Mike Frysinger586c7e62009-06-09 16:26:23 -07001734 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001735 unsigned long addr = (unsigned long)shmaddr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001736 int retval = -EINVAL;
Mike Frysinger586c7e62009-06-09 16:26:23 -07001737#ifdef CONFIG_MMU
1738 loff_t size = 0;
Dave Hansend3c97902014-12-12 16:58:19 -08001739 struct file *file;
Liam R. Howlett01293a62022-09-06 19:48:58 +00001740 VMA_ITERATOR(vmi, mm, addr);
Mike Frysinger586c7e62009-06-09 16:26:23 -07001741#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07001742
Hugh Dickinsdf1e2fb2006-03-24 03:18:06 -08001743 if (addr & ~PAGE_MASK)
1744 return retval;
1745
Michel Lespinassed8ed45c2020-06-08 21:33:25 -07001746 if (mmap_write_lock_killable(mm))
Michal Hocko91f4f942016-05-23 16:25:51 -07001747 return -EINTR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001748
1749 /*
1750 * This function tries to be smart and unmap shm segments that
1751 * were modified by partial mlock or munmap calls:
1752 * - It first determines the size of the shm segment that should be
1753 * unmapped: It searches for a vma that is backed by shm and that
1754 * started at address shmaddr. It records it's size and then unmaps
1755 * it.
1756 * - Then it unmaps all shm vmas that started at shmaddr and that
Dave Hansend3c97902014-12-12 16:58:19 -08001757 * are within the initially determined size and that are from the
1758 * same shm segment from which we determined the size.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001759 * Errors from do_munmap are ignored: the function only fails if
1760 * it's called with invalid parameters or if it's called to unmap
1761 * a part of a vma. Both calls in this function are for full vmas,
1762 * the parameters are directly copied from the vma itself and always
1763 * valid - therefore do_munmap cannot fail. (famous last words?)
1764 */
1765 /*
1766 * If it had been mremap()'d, the starting address would not
1767 * match the usual checks anyway. So assume all vma's are
1768 * above the starting address given.
1769 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001770
David Howells8feae132009-01-08 12:04:47 +00001771#ifdef CONFIG_MMU
Liam R. Howlett01293a62022-09-06 19:48:58 +00001772 for_each_vma(vmi, vma) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001773 /*
1774 * Check if the starting address would match, i.e. it's
1775 * a fragment created by mprotect() and/or munmap(), or it
1776 * otherwise it starts at this address with no hassles.
1777 */
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001778 if ((vma->vm_ops == &shm_vm_ops) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -07001779 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1780
Dave Hansend3c97902014-12-12 16:58:19 -08001781 /*
1782 * Record the file of the shm segment being
1783 * unmapped. With mremap(), someone could place
1784 * page from another segment but with equal offsets
1785 * in the range we are unmapping.
1786 */
1787 file = vma->vm_file;
Dave Hansen07a46ed2014-12-12 16:58:22 -08001788 size = i_size_read(file_inode(vma->vm_file));
Mike Rapoport897ab3e2017-02-24 14:58:22 -08001789 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start, NULL);
Liam R. Howlett01293a62022-09-06 19:48:58 +00001790 mas_pause(&vmi.mas);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001791 /*
1792 * We discovered the size of the shm segment, so
1793 * break out of here and fall through to the next
1794 * loop that uses the size information to stop
1795 * searching for matching vma's.
1796 */
1797 retval = 0;
Liam R. Howlett01293a62022-09-06 19:48:58 +00001798 vma = vma_next(&vmi);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001799 break;
1800 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001801 }
1802
1803 /*
1804 * We need look no further than the maximum address a fragment
1805 * could possibly have landed at. Also cast things to loff_t to
Lucas De Marchi25985ed2011-03-30 22:57:33 -03001806 * prevent overflows and make comparisons vs. equal-width types.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001807 */
KAMEZAWA Hiroyuki8e367092006-02-10 01:51:12 -08001808 size = PAGE_ALIGN(size);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001809 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001810 /* finding a matching vma now does not alter retval */
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001811 if ((vma->vm_ops == &shm_vm_ops) &&
Dave Hansend3c97902014-12-12 16:58:19 -08001812 ((vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) &&
Liam R. Howlett01293a62022-09-06 19:48:58 +00001813 (vma->vm_file == file)) {
Mike Rapoport897ab3e2017-02-24 14:58:22 -08001814 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start, NULL);
Liam R. Howlett01293a62022-09-06 19:48:58 +00001815 mas_pause(&vmi.mas);
1816 }
1817
1818 vma = vma_next(&vmi);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001819 }
1820
Shailesh Pandey63980c82016-12-14 15:06:10 -08001821#else /* CONFIG_MMU */
Liam R. Howlett01293a62022-09-06 19:48:58 +00001822 vma = vma_lookup(mm, addr);
David Howells8feae132009-01-08 12:04:47 +00001823 /* under NOMMU conditions, the exact address to be destroyed must be
Shailesh Pandey63980c82016-12-14 15:06:10 -08001824 * given
1825 */
Davidlohr Bueso530fcd162013-09-11 14:26:28 -07001826 if (vma && vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
Mike Rapoport897ab3e2017-02-24 14:58:22 -08001827 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start, NULL);
David Howells8feae132009-01-08 12:04:47 +00001828 retval = 0;
1829 }
1830
1831#endif
1832
Michel Lespinassed8ed45c2020-06-08 21:33:25 -07001833 mmap_write_unlock(mm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001834 return retval;
1835}
1836
Dominik Brodowskida1e27442018-03-20 20:09:48 +01001837SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
1838{
1839 return ksys_shmdt(shmaddr);
1840}
1841
Linus Torvalds1da177e2005-04-16 15:20:36 -07001842#ifdef CONFIG_PROC_FS
Mike Waychison19b49462005-09-06 15:17:10 -07001843static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001844{
Eric W. Biederman98f929b12018-03-23 00:29:57 -05001845 struct pid_namespace *pid_ns = ipc_seq_pid_ns(s);
Eric W. Biederman1efdb692012-02-07 16:54:11 -08001846 struct user_namespace *user_ns = seq_user_ns(s);
Kees Cookade9f912017-08-02 13:32:21 -07001847 struct kern_ipc_perm *ipcp = it;
1848 struct shmid_kernel *shp;
Helge Dellerb7952182010-10-27 15:34:16 -07001849 unsigned long rss = 0, swp = 0;
1850
Kees Cookade9f912017-08-02 13:32:21 -07001851 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
Helge Dellerb7952182010-10-27 15:34:16 -07001852 shm_add_rss_swap(shp, &rss, &swp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001853
Paul Menage6c826812008-06-12 15:21:49 -07001854#if BITS_PER_LONG <= 32
1855#define SIZE_SPEC "%10lu"
1856#else
1857#define SIZE_SPEC "%21lu"
1858#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07001859
Joe Perches7f032d62015-04-15 16:17:54 -07001860 seq_printf(s,
1861 "%10d %10d %4o " SIZE_SPEC " %5u %5u "
Deepa Dinamani7ff28192017-08-02 19:51:14 -07001862 "%5lu %5u %5u %5u %5u %10llu %10llu %10llu "
Joe Perches7f032d62015-04-15 16:17:54 -07001863 SIZE_SPEC " " SIZE_SPEC "\n",
1864 shp->shm_perm.key,
1865 shp->shm_perm.id,
1866 shp->shm_perm.mode,
1867 shp->shm_segsz,
Eric W. Biederman98f929b12018-03-23 00:29:57 -05001868 pid_nr_ns(shp->shm_cprid, pid_ns),
1869 pid_nr_ns(shp->shm_lprid, pid_ns),
Joe Perches7f032d62015-04-15 16:17:54 -07001870 shp->shm_nattch,
1871 from_kuid_munged(user_ns, shp->shm_perm.uid),
1872 from_kgid_munged(user_ns, shp->shm_perm.gid),
1873 from_kuid_munged(user_ns, shp->shm_perm.cuid),
1874 from_kgid_munged(user_ns, shp->shm_perm.cgid),
1875 shp->shm_atim,
1876 shp->shm_dtim,
1877 shp->shm_ctim,
1878 rss * PAGE_SIZE,
1879 swp * PAGE_SIZE);
1880
1881 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001882}
1883#endif