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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;
Eric W. Biedermana2e102c2018-03-22 21:34:44 -050063 struct user_struct *mlock_user;
64
65 /* The task created the shm object. NULL if the task is dead. */
66 struct task_struct *shm_creator;
67 struct list_head shm_clist; /* list by creator */
68} __randomize_layout;
69
70/* shm_mode upper byte flags */
71#define SHM_DEST 01000 /* segment will be destroyed on last detach */
72#define SHM_LOCKED 02000 /* segment will not be swapped */
73
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -080074struct shm_file_data {
75 int id;
76 struct ipc_namespace *ns;
77 struct file *file;
78 const struct vm_operations_struct *vm_ops;
79};
80
81#define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
82
Arjan van de Ven9a321442007-02-12 00:55:35 -080083static const struct file_operations shm_file_operations;
Alexey Dobriyanf0f37e2f2009-09-27 22:29:37 +040084static const struct vm_operations_struct shm_vm_ops;
Linus Torvalds1da177e2005-04-16 15:20:36 -070085
Pierre Peiffered2ddbf2008-02-08 04:18:57 -080086#define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS])
Linus Torvalds1da177e2005-04-16 15:20:36 -070087
Kirill Korotaev4e982312006-10-02 02:18:22 -070088#define shm_unlock(shp) \
89 ipc_unlock(&(shp)->shm_perm)
Kirill Korotaev4e982312006-10-02 02:18:22 -070090
Nadia Derbey7748dbf2007-10-18 23:40:49 -070091static int newseg(struct ipc_namespace *, struct ipc_params *);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -080092static void shm_open(struct vm_area_struct *vma);
93static void shm_close(struct vm_area_struct *vma);
Manfred Spraul239521f2014-01-27 17:07:04 -080094static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -070095#ifdef CONFIG_PROC_FS
Mike Waychison19b49462005-09-06 15:17:10 -070096static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
Linus Torvalds1da177e2005-04-16 15:20:36 -070097#endif
98
Davidlohr Buesoeae04d22018-08-21 22:01:56 -070099void shm_init_ns(struct ipc_namespace *ns)
Kirill Korotaev4e982312006-10-02 02:18:22 -0700100{
Kirill Korotaev4e982312006-10-02 02:18:22 -0700101 ns->shm_ctlmax = SHMMAX;
102 ns->shm_ctlall = SHMALL;
103 ns->shm_ctlmni = SHMMNI;
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700104 ns->shm_rmid_forced = 0;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700105 ns->shm_tot = 0;
Davidlohr Buesoeae04d22018-08-21 22:01:56 -0700106 ipc_init_ids(&shm_ids(ns));
Kirill Korotaev4e982312006-10-02 02:18:22 -0700107}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700109/*
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700110 * Called with shm_ids.rwsem (writer) and the shp structure locked.
111 * Only shm_ids.rwsem remains locked on exit.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700112 */
Pierre Peiffer01b8b072008-02-08 04:18:57 -0800113static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
Kirill Korotaev4e982312006-10-02 02:18:22 -0700114{
Pierre Peiffer01b8b072008-02-08 04:18:57 -0800115 struct shmid_kernel *shp;
Shailesh Pandey63980c82016-12-14 15:06:10 -0800116
Pierre Peiffer01b8b072008-02-08 04:18:57 -0800117 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
118
Manfred Spraul239521f2014-01-27 17:07:04 -0800119 if (shp->shm_nattch) {
Kirill Korotaev4e982312006-10-02 02:18:22 -0700120 shp->shm_perm.mode |= SHM_DEST;
121 /* Do not find it any more */
Guillaume Knispel0cfb6ae2017-09-08 16:17:55 -0700122 ipc_set_key_private(&shm_ids(ns), &shp->shm_perm);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700123 shm_unlock(shp);
124 } else
125 shm_destroy(ns, shp);
126}
127
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800128#ifdef CONFIG_IPC_NS
Kirill Korotaev4e982312006-10-02 02:18:22 -0700129void shm_exit_ns(struct ipc_namespace *ns)
130{
Pierre Peiffer01b8b072008-02-08 04:18:57 -0800131 free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
Serge E. Hallyn7d6feeb2009-12-15 16:47:27 -0800132 idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
Guillaume Knispel0cfb6ae2017-09-08 16:17:55 -0700133 rhashtable_destroy(&ns->ids[IPC_SHM_IDS].key_ht);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700134}
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800135#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136
Linus Torvalds140d0b22011-08-04 19:35:59 -1000137static int __init ipc_ns_init(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138{
Davidlohr Buesoeae04d22018-08-21 22:01:56 -0700139 shm_init_ns(&init_ipc_ns);
140 return 0;
Linus Torvalds140d0b22011-08-04 19:35:59 -1000141}
142
143pure_initcall(ipc_ns_init);
144
Manfred Spraul239521f2014-01-27 17:07:04 -0800145void __init shm_init(void)
Linus Torvalds140d0b22011-08-04 19:35:59 -1000146{
Mike Waychison19b49462005-09-06 15:17:10 -0700147 ipc_init_proc_interface("sysvipc/shm",
Helge Dellerb7952182010-10-27 15:34:16 -0700148#if BITS_PER_LONG <= 32
149 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
150#else
151 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
152#endif
Kirill Korotaev4e982312006-10-02 02:18:22 -0700153 IPC_SHM_IDS, sysvipc_shm_proc_show);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154}
155
Davidlohr Bueso8b8d52a2013-09-11 14:26:15 -0700156static inline struct shmid_kernel *shm_obtain_object(struct ipc_namespace *ns, int id)
157{
Davidlohr Bueso55b7ae52015-06-30 14:58:42 -0700158 struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(&shm_ids(ns), id);
Davidlohr Bueso8b8d52a2013-09-11 14:26:15 -0700159
160 if (IS_ERR(ipcp))
161 return ERR_CAST(ipcp);
162
163 return container_of(ipcp, struct shmid_kernel, shm_perm);
164}
165
166static inline struct shmid_kernel *shm_obtain_object_check(struct ipc_namespace *ns, int id)
167{
168 struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&shm_ids(ns), id);
169
170 if (IS_ERR(ipcp))
171 return ERR_CAST(ipcp);
172
173 return container_of(ipcp, struct shmid_kernel, shm_perm);
174}
175
Nadia Derbey3e148c72007-10-18 23:40:54 -0700176/*
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700177 * shm_lock_(check_) routines are called in the paths where the rwsem
Nadia Derbey00c2bf82008-07-25 01:48:03 -0700178 * is not necessarily held.
Nadia Derbey3e148c72007-10-18 23:40:54 -0700179 */
Nadia Derbey023a5352007-10-18 23:40:51 -0700180static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181{
Davidlohr Bueso82061c52018-08-21 22:01:41 -0700182 struct kern_ipc_perm *ipcp;
Nadia Derbey03f02c72007-10-18 23:40:51 -0700183
Davidlohr Bueso82061c52018-08-21 22:01:41 -0700184 rcu_read_lock();
185 ipcp = ipc_obtain_object_idr(&shm_ids(ns), id);
186 if (IS_ERR(ipcp))
187 goto err;
188
189 ipc_lock_object(ipcp);
190 /*
191 * ipc_rmid() may have already freed the ID while ipc_lock_object()
192 * was spinning: here verify that the structure is still valid.
193 * Upon races with RMID, return -EIDRM, thus indicating that
194 * the ID points to a removed identifier.
195 */
196 if (ipc_valid_object(ipcp)) {
197 /* return a locked ipc object upon success */
198 return container_of(ipcp, struct shmid_kernel, shm_perm);
199 }
200
201 ipc_unlock_object(ipcp);
Davidlohr Bueso9c21dae2018-09-04 15:46:02 -0700202 ipcp = ERR_PTR(-EIDRM);
Davidlohr Bueso82061c52018-08-21 22:01:41 -0700203err:
204 rcu_read_unlock();
Davidlohr Buesoc5c89752015-06-30 14:58:36 -0700205 /*
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800206 * Callers of shm_lock() must validate the status of the returned ipc
Davidlohr Bueso82061c52018-08-21 22:01:41 -0700207 * object pointer and error out as appropriate.
Davidlohr Buesoc5c89752015-06-30 14:58:36 -0700208 */
Kees Cook59cf0a92018-10-05 15:51:48 -0700209 return ERR_CAST(ipcp);
Nadia Derbey023a5352007-10-18 23:40:51 -0700210}
211
Vasiliy Kulikov4c677e22011-07-29 03:56:40 +0400212static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
213{
214 rcu_read_lock();
Davidlohr Buesocf9d5d72013-07-08 16:01:11 -0700215 ipc_lock_object(&ipcp->shm_perm);
Vasiliy Kulikov4c677e22011-07-29 03:56:40 +0400216}
217
Davidlohr Bueso53dad6d2013-09-23 17:04:45 -0700218static void shm_rcu_free(struct rcu_head *head)
219{
Manfred Sprauldba4cdd2017-07-12 14:34:41 -0700220 struct kern_ipc_perm *ptr = container_of(head, struct kern_ipc_perm,
221 rcu);
222 struct shmid_kernel *shp = container_of(ptr, struct shmid_kernel,
223 shm_perm);
Eric W. Biederman7191adf2018-03-22 21:08:27 -0500224 security_shm_free(&shp->shm_perm);
Kees Cook42e618f2017-07-12 14:35:25 -0700225 kvfree(shp);
Davidlohr Bueso53dad6d2013-09-23 17:04:45 -0700226}
227
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700228static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229{
Jack Millerab602f72014-08-08 14:23:19 -0700230 list_del(&s->shm_clist);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700231 ipc_rmid(&shm_ids(ns), &s->shm_perm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232}
233
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800235static int __shm_open(struct vm_area_struct *vma)
Kirill Korotaev4e982312006-10-02 02:18:22 -0700236{
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800237 struct file *file = vma->vm_file;
238 struct shm_file_data *sfd = shm_file_data(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239 struct shmid_kernel *shp;
240
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800241 shp = shm_lock(sfd->ns, sfd->id);
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800242
243 if (IS_ERR(shp))
244 return PTR_ERR(shp);
245
Eric Biggers3f053172018-04-13 15:35:30 -0700246 if (shp->shm_file != sfd->file) {
247 /* ID was reused */
248 shm_unlock(shp);
249 return -EINVAL;
250 }
251
Deepa Dinamani7ff28192017-08-02 19:51:14 -0700252 shp->shm_atim = ktime_get_real_seconds();
Eric W. Biederman98f929b12018-03-23 00:29:57 -0500253 ipc_update_pid(&shp->shm_lprid, task_tgid(current));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254 shp->shm_nattch++;
255 shm_unlock(shp);
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800256 return 0;
257}
258
259/* This is called by fork, once for every shm attach. */
260static void shm_open(struct vm_area_struct *vma)
261{
262 int err = __shm_open(vma);
263 /*
264 * We raced in the idr lookup or with shm_destroy().
265 * Either way, the ID is busted.
266 */
267 WARN_ON_ONCE(err);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268}
269
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270/*
271 * shm_destroy - free the struct shmid_kernel
272 *
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700273 * @ns: namespace
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274 * @shp: struct to free
275 *
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700276 * It has to be called with shp and shm_ids.rwsem (writer) locked,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277 * but returns with shp unlocked and freed.
278 */
Kirill Korotaev4e982312006-10-02 02:18:22 -0700279static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280{
Greg Thelena399b292013-11-21 14:32:00 -0800281 struct file *shm_file;
282
283 shm_file = shp->shm_file;
284 shp->shm_file = NULL;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700285 ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700286 shm_rmid(ns, shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 shm_unlock(shp);
Greg Thelena399b292013-11-21 14:32:00 -0800288 if (!is_file_hugepages(shm_file))
289 shmem_lock(shm_file, 0, shp->mlock_user);
Hugh Dickins353d5c32009-08-24 16:30:28 +0100290 else if (shp->mlock_user)
Dave Hansen07a46ed2014-12-12 16:58:22 -0800291 user_shm_unlock(i_size_read(file_inode(shm_file)),
292 shp->mlock_user);
Greg Thelena399b292013-11-21 14:32:00 -0800293 fput(shm_file);
Eric W. Biederman98f929b12018-03-23 00:29:57 -0500294 ipc_update_pid(&shp->shm_cprid, NULL);
295 ipc_update_pid(&shp->shm_lprid, NULL);
Manfred Sprauldba4cdd2017-07-12 14:34:41 -0700296 ipc_rcu_putref(&shp->shm_perm, shm_rcu_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297}
298
299/*
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700300 * shm_may_destroy - identifies whether shm segment should be destroyed now
301 *
302 * Returns true if and only if there are no active users of the segment and
303 * one of the following is true:
304 *
305 * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
306 *
307 * 2) sysctl kernel.shm_rmid_forced is set to 1.
308 */
309static bool shm_may_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
310{
311 return (shp->shm_nattch == 0) &&
312 (ns->shm_rmid_forced ||
313 (shp->shm_perm.mode & SHM_DEST));
314}
315
316/*
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800317 * remove the attach descriptor vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318 * free memory for segment if it is marked destroyed.
319 * The descriptor has already been removed from the current->mm->mmap list
320 * and will later be kfree()d.
321 */
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800322static void shm_close(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323{
Manfred Spraul239521f2014-01-27 17:07:04 -0800324 struct file *file = vma->vm_file;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800325 struct shm_file_data *sfd = shm_file_data(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 struct shmid_kernel *shp;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800327 struct ipc_namespace *ns = sfd->ns;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700328
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700329 down_write(&shm_ids(ns).rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330 /* remove from the list of attaches of the shm segment */
Nadia Derbey00c2bf82008-07-25 01:48:03 -0700331 shp = shm_lock(ns, sfd->id);
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800332
333 /*
334 * We raced in the idr lookup or with shm_destroy().
335 * Either way, the ID is busted.
336 */
337 if (WARN_ON_ONCE(IS_ERR(shp)))
338 goto done; /* no-op */
339
Eric W. Biederman98f929b12018-03-23 00:29:57 -0500340 ipc_update_pid(&shp->shm_lprid, task_tgid(current));
Deepa Dinamani7ff28192017-08-02 19:51:14 -0700341 shp->shm_dtim = ktime_get_real_seconds();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342 shp->shm_nattch--;
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700343 if (shm_may_destroy(ns, shp))
Kirill Korotaev4e982312006-10-02 02:18:22 -0700344 shm_destroy(ns, shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345 else
346 shm_unlock(shp);
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800347done:
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700348 up_write(&shm_ids(ns).rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349}
350
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700351/* Called with ns->shm_ids(ns).rwsem locked */
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700352static int shm_try_destroy_orphaned(int id, void *p, void *data)
353{
354 struct ipc_namespace *ns = data;
Vasiliy Kulikov4c677e22011-07-29 03:56:40 +0400355 struct kern_ipc_perm *ipcp = p;
356 struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700357
358 /*
359 * We want to destroy segments without users and with already
360 * exit'ed originating process.
Vasiliy Kulikov4c677e22011-07-29 03:56:40 +0400361 *
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700362 * As shp->* are changed under rwsem, it's safe to skip shp locking.
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700363 */
Vasiliy Kulikov4c677e22011-07-29 03:56:40 +0400364 if (shp->shm_creator != NULL)
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700365 return 0;
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700366
Vasiliy Kulikov4c677e22011-07-29 03:56:40 +0400367 if (shm_may_destroy(ns, shp)) {
368 shm_lock_by_ptr(shp);
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700369 shm_destroy(ns, shp);
Vasiliy Kulikov4c677e22011-07-29 03:56:40 +0400370 }
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700371 return 0;
372}
373
374void shm_destroy_orphaned(struct ipc_namespace *ns)
375{
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700376 down_write(&shm_ids(ns).rwsem);
Vasiliy Kulikov33a30ed2011-08-03 22:26:55 +0400377 if (shm_ids(ns).in_use)
Vasiliy Kulikov4c677e22011-07-29 03:56:40 +0400378 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700379 up_write(&shm_ids(ns).rwsem);
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700380}
381
Jack Miller83293c0f52014-08-08 14:23:21 -0700382/* Locking assumes this will only be called with task == current */
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700383void exit_shm(struct task_struct *task)
384{
Vasiliy Kulikov4c677e22011-07-29 03:56:40 +0400385 struct ipc_namespace *ns = task->nsproxy->ipc_ns;
Jack Millerab602f72014-08-08 14:23:19 -0700386 struct shmid_kernel *shp, *n;
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700387
Jack Miller83293c0f52014-08-08 14:23:21 -0700388 if (list_empty(&task->sysvshm.shm_clist))
Vasiliy Kulikov298507d2011-08-03 22:28:26 +0400389 return;
390
Jack Miller83293c0f52014-08-08 14:23:21 -0700391 /*
392 * If kernel.shm_rmid_forced is not set then only keep track of
393 * which shmids are orphaned, so that a later set of the sysctl
394 * can clean them up.
395 */
396 if (!ns->shm_rmid_forced) {
397 down_read(&shm_ids(ns).rwsem);
398 list_for_each_entry(shp, &task->sysvshm.shm_clist, shm_clist)
399 shp->shm_creator = NULL;
400 /*
401 * Only under read lock but we are only called on current
402 * so no entry on the list will be shared.
403 */
404 list_del(&task->sysvshm.shm_clist);
405 up_read(&shm_ids(ns).rwsem);
406 return;
407 }
408
409 /*
410 * Destroy all already created segments, that were not yet mapped,
411 * and mark any mapped as orphan to cover the sysctl toggling.
412 * Destroy is skipped if shm_may_destroy() returns false.
413 */
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700414 down_write(&shm_ids(ns).rwsem);
Jack Miller83293c0f52014-08-08 14:23:21 -0700415 list_for_each_entry_safe(shp, n, &task->sysvshm.shm_clist, shm_clist) {
416 shp->shm_creator = NULL;
417
418 if (shm_may_destroy(ns, shp)) {
419 shm_lock_by_ptr(shp);
420 shm_destroy(ns, shp);
421 }
422 }
423
424 /* Remove the list head from any segments still attached. */
Jack Millerab602f72014-08-08 14:23:19 -0700425 list_del(&task->sysvshm.shm_clist);
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700426 up_write(&shm_ids(ns).rwsem);
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700427}
428
Souptick Joarder14f28f572018-06-14 15:27:55 -0700429static vm_fault_t shm_fault(struct vm_fault *vmf)
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800430{
Dave Jiang11bac802017-02-24 14:56:41 -0800431 struct file *file = vmf->vma->vm_file;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800432 struct shm_file_data *sfd = shm_file_data(file);
433
Dave Jiang11bac802017-02-24 14:56:41 -0800434 return sfd->vm_ops->fault(vmf);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800435}
436
Mike Kravetz3d942ee2018-03-28 16:01:01 -0700437static int shm_split(struct vm_area_struct *vma, unsigned long addr)
438{
439 struct file *file = vma->vm_file;
440 struct shm_file_data *sfd = shm_file_data(file);
441
Andrew Mortona61fc2c2018-04-10 16:35:42 -0700442 if (sfd->vm_ops->split)
Mike Kravetz3d942ee2018-03-28 16:01:01 -0700443 return sfd->vm_ops->split(vma, addr);
444
445 return 0;
446}
447
Jane Chueec36362018-08-02 15:36:05 -0700448static unsigned long shm_pagesize(struct vm_area_struct *vma)
449{
450 struct file *file = vma->vm_file;
451 struct shm_file_data *sfd = shm_file_data(file);
452
453 if (sfd->vm_ops->pagesize)
454 return sfd->vm_ops->pagesize(vma);
455
456 return PAGE_SIZE;
457}
458
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800459#ifdef CONFIG_NUMA
Adrian Bunkd823e3e2007-10-16 23:26:42 -0700460static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800461{
462 struct file *file = vma->vm_file;
463 struct shm_file_data *sfd = shm_file_data(file);
464 int err = 0;
Shailesh Pandey63980c82016-12-14 15:06:10 -0800465
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800466 if (sfd->vm_ops->set_policy)
467 err = sfd->vm_ops->set_policy(vma, new);
468 return err;
469}
470
Adrian Bunkd823e3e2007-10-16 23:26:42 -0700471static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
472 unsigned long addr)
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800473{
474 struct file *file = vma->vm_file;
475 struct shm_file_data *sfd = shm_file_data(file);
476 struct mempolicy *pol = NULL;
477
478 if (sfd->vm_ops->get_policy)
479 pol = sfd->vm_ops->get_policy(vma, addr);
Lee Schermerhorn52cd3b02008-04-28 02:13:16 -0700480 else if (vma->vm_policy)
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800481 pol = vma->vm_policy;
Lee Schermerhorn52cd3b02008-04-28 02:13:16 -0700482
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800483 return pol;
484}
485#endif
486
Manfred Spraul239521f2014-01-27 17:07:04 -0800487static int shm_mmap(struct file *file, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488{
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800489 struct shm_file_data *sfd = shm_file_data(file);
David Howellsb0e15192006-01-06 00:11:42 -0800490 int ret;
491
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800492 /*
Eric Biggers3f053172018-04-13 15:35:30 -0700493 * In case of remap_file_pages() emulation, the file can represent an
494 * IPC ID that was removed, and possibly even reused by another shm
495 * segment already. Propagate this case as an error to caller.
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800496 */
Shailesh Pandey63980c82016-12-14 15:06:10 -0800497 ret = __shm_open(vma);
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800498 if (ret)
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800499 return ret;
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800500
Miklos Szeredif74ac012017-02-20 16:51:23 +0100501 ret = call_mmap(sfd->file, vma);
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800502 if (ret) {
503 shm_close(vma);
504 return ret;
505 }
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800506 sfd->vm_ops = vma->vm_ops;
David Howells2e92a3b2007-07-31 00:37:24 -0700507#ifdef CONFIG_MMU
Davidlohr Buesod0edd852015-09-09 15:39:20 -0700508 WARN_ON(!sfd->vm_ops->fault);
David Howells2e92a3b2007-07-31 00:37:24 -0700509#endif
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800510 vma->vm_ops = &shm_vm_ops;
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800511 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512}
513
Kirill Korotaev4e982312006-10-02 02:18:22 -0700514static int shm_release(struct inode *ino, struct file *file)
515{
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800516 struct shm_file_data *sfd = shm_file_data(file);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700517
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800518 put_ipc_ns(sfd->ns);
Eric Biggers3f053172018-04-13 15:35:30 -0700519 fput(sfd->file);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800520 shm_file_data(file) = NULL;
521 kfree(sfd);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700522 return 0;
523}
524
Josef Bacik02c24a82011-07-16 20:44:56 -0400525static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
Adam Litke516dffd2007-03-01 15:46:08 -0800526{
Adam Litke516dffd2007-03-01 15:46:08 -0800527 struct shm_file_data *sfd = shm_file_data(file);
Adam Litke516dffd2007-03-01 15:46:08 -0800528
Christoph Hellwig7ea80852010-05-26 17:53:25 +0200529 if (!sfd->file->f_op->fsync)
530 return -EINVAL;
Jeff Layton0f410742017-07-05 15:26:50 -0400531 return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
Adam Litke516dffd2007-03-01 15:46:08 -0800532}
533
Will Deacon7d8a4562012-06-07 14:21:13 -0700534static long shm_fallocate(struct file *file, int mode, loff_t offset,
535 loff_t len)
536{
537 struct shm_file_data *sfd = shm_file_data(file);
538
539 if (!sfd->file->f_op->fallocate)
540 return -EOPNOTSUPP;
541 return sfd->file->f_op->fallocate(file, mode, offset, len);
542}
543
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800544static unsigned long shm_get_unmapped_area(struct file *file,
545 unsigned long addr, unsigned long len, unsigned long pgoff,
546 unsigned long flags)
547{
548 struct shm_file_data *sfd = shm_file_data(file);
Shailesh Pandey63980c82016-12-14 15:06:10 -0800549
Al Viroc4caa772009-11-30 08:38:43 -0500550 return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
551 pgoff, flags);
Adam Litke516dffd2007-03-01 15:46:08 -0800552}
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800553
Arjan van de Ven9a321442007-02-12 00:55:35 -0800554static const struct file_operations shm_file_operations = {
Kirill Korotaev4e982312006-10-02 02:18:22 -0700555 .mmap = shm_mmap,
Adam Litke516dffd2007-03-01 15:46:08 -0800556 .fsync = shm_fsync,
Kirill Korotaev4e982312006-10-02 02:18:22 -0700557 .release = shm_release,
David Howellsed5e5892010-01-15 17:01:32 -0800558 .get_unmapped_area = shm_get_unmapped_area,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200559 .llseek = noop_llseek,
Will Deacon7d8a4562012-06-07 14:21:13 -0700560 .fallocate = shm_fallocate,
Al Viroc4caa772009-11-30 08:38:43 -0500561};
562
Hugh Dickinsc01d5b32016-07-26 15:26:15 -0700563/*
564 * shm_file_operations_huge is now identical to shm_file_operations,
565 * but we keep it distinct for the sake of is_file_shm_hugepages().
566 */
Al Viroc4caa772009-11-30 08:38:43 -0500567static const struct file_operations shm_file_operations_huge = {
568 .mmap = shm_mmap,
569 .fsync = shm_fsync,
570 .release = shm_release,
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800571 .get_unmapped_area = shm_get_unmapped_area,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200572 .llseek = noop_llseek,
Will Deacon7d8a4562012-06-07 14:21:13 -0700573 .fallocate = shm_fallocate,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574};
575
Yaowei Bai2954e4402016-01-20 15:01:11 -0800576bool is_file_shm_hugepages(struct file *file)
Al Viroc4caa772009-11-30 08:38:43 -0500577{
578 return file->f_op == &shm_file_operations_huge;
579}
580
Alexey Dobriyanf0f37e2f2009-09-27 22:29:37 +0400581static const struct vm_operations_struct shm_vm_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700582 .open = shm_open, /* callback for a new vm-area open */
583 .close = shm_close, /* callback for when the vm-area is released */
Nick Piggin54cb8822007-07-19 01:46:59 -0700584 .fault = shm_fault,
Mike Kravetz3d942ee2018-03-28 16:01:01 -0700585 .split = shm_split,
Jane Chueec36362018-08-02 15:36:05 -0700586 .pagesize = shm_pagesize,
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800587#if defined(CONFIG_NUMA)
588 .set_policy = shm_set_policy,
589 .get_policy = shm_get_policy,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590#endif
591};
592
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700593/**
594 * newseg - Create a new shared memory segment
595 * @ns: namespace
596 * @params: ptr to the structure that contains key, size and shmflg
597 *
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700598 * Called with shm_ids.rwsem held as a writer.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700599 */
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700600static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700601{
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700602 key_t key = params->key;
603 int shmflg = params->flg;
604 size_t size = params->u.size;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605 int error;
606 struct shmid_kernel *shp;
Robin Holtd69f3ba2013-04-30 19:15:54 -0700607 size_t numpages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
Manfred Spraul239521f2014-01-27 17:07:04 -0800608 struct file *file;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609 char name[13];
KOSAKI Motohiroca16d142011-05-26 19:16:19 +0900610 vm_flags_t acctflag = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700611
Kirill Korotaev4e982312006-10-02 02:18:22 -0700612 if (size < SHMMIN || size > ns->shm_ctlmax)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613 return -EINVAL;
614
Manfred Spraul13763272014-06-06 14:37:41 -0700615 if (numpages << PAGE_SHIFT < size)
616 return -ENOSPC;
617
Manfred Spraul09c6eb12014-06-06 14:37:40 -0700618 if (ns->shm_tot + numpages < ns->shm_tot ||
619 ns->shm_tot + numpages > ns->shm_ctlall)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620 return -ENOSPC;
621
Kees Cook42e618f2017-07-12 14:35:25 -0700622 shp = kvmalloc(sizeof(*shp), GFP_KERNEL);
623 if (unlikely(!shp))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624 return -ENOMEM;
625
626 shp->shm_perm.key = key;
Andrew Mortonb33291c2006-01-08 01:02:21 -0800627 shp->shm_perm.mode = (shmflg & S_IRWXUGO);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700628 shp->mlock_user = NULL;
629
630 shp->shm_perm.security = NULL;
Eric W. Biederman7191adf2018-03-22 21:08:27 -0500631 error = security_shm_alloc(&shp->shm_perm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700632 if (error) {
Kees Cook42e618f2017-07-12 14:35:25 -0700633 kvfree(shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634 return error;
635 }
636
Manfred Spraul239521f2014-01-27 17:07:04 -0800637 sprintf(name, "SYSV%08x", key);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700638 if (shmflg & SHM_HUGETLB) {
Andrew Mortonc103a4d2013-07-08 16:01:08 -0700639 struct hstate *hs;
Li Zefan091d0d52013-05-09 15:08:15 +0800640 size_t hugesize;
641
Andrew Mortonc103a4d2013-07-08 16:01:08 -0700642 hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
Li Zefan091d0d52013-05-09 15:08:15 +0800643 if (!hs) {
644 error = -EINVAL;
645 goto no_file;
646 }
647 hugesize = ALIGN(size, huge_page_size(hs));
Naoya Horiguchiaf73e4d2013-05-07 16:18:13 -0700648
Mel Gorman5a6fe122009-02-10 14:02:27 +0000649 /* hugetlb_file_setup applies strict accounting */
650 if (shmflg & SHM_NORESERVE)
651 acctflag = VM_NORESERVE;
Naoya Horiguchiaf73e4d2013-05-07 16:18:13 -0700652 file = hugetlb_file_setup(name, hugesize, acctflag,
Andi Kleen42d73952012-12-11 16:01:34 -0800653 &shp->mlock_user, HUGETLB_SHMFS_INODE,
654 (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655 } else {
Badari Pulavartybf8f9722005-11-07 00:59:27 -0800656 /*
657 * Do not allow no accounting for OVERCOMMIT_NEVER, even
Manfred Spraul239521f2014-01-27 17:07:04 -0800658 * if it's asked for.
Badari Pulavartybf8f9722005-11-07 00:59:27 -0800659 */
660 if ((shmflg & SHM_NORESERVE) &&
661 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
Linus Torvaldsfc8744a2009-01-31 15:08:56 -0800662 acctflag = VM_NORESERVE;
Stephen Smalleye1832f22015-08-06 15:46:55 -0700663 file = shmem_kernel_file_setup(name, size, acctflag);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664 }
665 error = PTR_ERR(file);
666 if (IS_ERR(file))
667 goto no_file;
668
Eric W. Biederman98f929b12018-03-23 00:29:57 -0500669 shp->shm_cprid = get_pid(task_tgid(current));
670 shp->shm_lprid = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671 shp->shm_atim = shp->shm_dtim = 0;
Deepa Dinamani7ff28192017-08-02 19:51:14 -0700672 shp->shm_ctim = ktime_get_real_seconds();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673 shp->shm_segsz = size;
674 shp->shm_nattch = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700675 shp->shm_file = file;
Vasiliy Kulikov5774ed02011-07-29 03:55:31 +0400676 shp->shm_creator = current;
Linus Torvaldsb9a53222015-09-30 12:48:40 -0400677
Davidlohr Bueso39c96a12017-11-17 15:31:11 -0800678 /* ipc_addid() locks shp upon success. */
Manfred Spraula2642f82017-07-12 14:35:16 -0700679 error = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
680 if (error < 0)
Linus Torvaldsb9a53222015-09-30 12:48:40 -0400681 goto no_id;
Linus Torvaldsb9a53222015-09-30 12:48:40 -0400682
Jack Millerab602f72014-08-08 14:23:19 -0700683 list_add(&shp->shm_clist, &current->sysvshm.shm_clist);
Davidlohr Buesodbfcd912013-07-08 16:01:09 -0700684
Badari Pulavarty30475cc2007-06-16 10:15:59 -0700685 /*
686 * shmid gets reported as "inode#" in /proc/pid/maps.
687 * proc-ps tools use this. Changing this will break them.
688 */
Al Viro496ad9a2013-01-23 17:07:38 -0500689 file_inode(file)->i_ino = shp->shm_perm.id;
Krishnakumar R551110a2005-10-29 18:16:45 -0700690
Kirill Korotaev4e982312006-10-02 02:18:22 -0700691 ns->shm_tot += numpages;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700692 error = shp->shm_perm.id;
Davidlohr Buesodbfcd912013-07-08 16:01:09 -0700693
Davidlohr Buesocf9d5d72013-07-08 16:01:11 -0700694 ipc_unlock_object(&shp->shm_perm);
Davidlohr Buesodbfcd912013-07-08 16:01:09 -0700695 rcu_read_unlock();
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700696 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697
698no_id:
Eric W. Biederman2236d4d2018-03-28 13:38:55 -0500699 ipc_update_pid(&shp->shm_cprid, NULL);
700 ipc_update_pid(&shp->shm_lprid, NULL);
Hugh Dickins2195d2812009-09-12 12:21:27 +0100701 if (is_file_hugepages(file) && shp->mlock_user)
Hugh Dickins353d5c32009-08-24 16:30:28 +0100702 user_shm_unlock(size, shp->mlock_user);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703 fput(file);
Manfred Spraul39cfffd2018-08-21 22:01:29 -0700704 ipc_rcu_putref(&shp->shm_perm, shm_rcu_free);
705 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700706no_file:
Manfred Spraula2642f82017-07-12 14:35:16 -0700707 call_rcu(&shp->shm_perm.rcu, shm_rcu_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700708 return error;
709}
710
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700711/*
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700712 * Called with shm_ids.rwsem and ipcp locked.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700713 */
Nadia Derbey03f02c72007-10-18 23:40:51 -0700714static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
715 struct ipc_params *params)
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700716{
Nadia Derbey03f02c72007-10-18 23:40:51 -0700717 struct shmid_kernel *shp;
718
719 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
720 if (shp->shm_segsz < params->u.size)
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700721 return -EINVAL;
722
723 return 0;
724}
725
Dominik Brodowski65749e02018-03-20 20:07:53 +0100726long ksys_shmget(key_t key, size_t size, int shmflg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727{
Kirill Korotaev4e982312006-10-02 02:18:22 -0700728 struct ipc_namespace *ns;
Mathias Krauseeb66ec42014-06-06 14:37:36 -0700729 static const struct ipc_ops shm_ops = {
730 .getnew = newseg,
Eric W. Biederman50ab44b2018-03-23 23:41:55 -0500731 .associate = security_shm_associate,
Mathias Krauseeb66ec42014-06-06 14:37:36 -0700732 .more_checks = shm_more_checks,
733 };
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700734 struct ipc_params shm_params;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735
Kirill Korotaev4e982312006-10-02 02:18:22 -0700736 ns = current->nsproxy->ipc_ns;
737
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700738 shm_params.key = key;
739 shm_params.flg = shmflg;
740 shm_params.u.size = size;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700741
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700742 return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743}
744
Dominik Brodowski65749e02018-03-20 20:07:53 +0100745SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
746{
747 return ksys_shmget(key, size, shmflg);
748}
749
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
751{
Manfred Spraul239521f2014-01-27 17:07:04 -0800752 switch (version) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753 case IPC_64:
754 return copy_to_user(buf, in, sizeof(*in));
755 case IPC_OLD:
756 {
757 struct shmid_ds out;
758
Vasiliy Kulikov3af54c92010-10-30 18:22:49 +0400759 memset(&out, 0, sizeof(out));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700760 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
761 out.shm_segsz = in->shm_segsz;
762 out.shm_atime = in->shm_atime;
763 out.shm_dtime = in->shm_dtime;
764 out.shm_ctime = in->shm_ctime;
765 out.shm_cpid = in->shm_cpid;
766 out.shm_lpid = in->shm_lpid;
767 out.shm_nattch = in->shm_nattch;
768
769 return copy_to_user(buf, &out, sizeof(out));
770 }
771 default:
772 return -EINVAL;
773 }
774}
775
Pierre Peiffer016d7132008-04-29 01:00:50 -0700776static inline unsigned long
777copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700778{
Manfred Spraul239521f2014-01-27 17:07:04 -0800779 switch (version) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780 case IPC_64:
Pierre Peiffer016d7132008-04-29 01:00:50 -0700781 if (copy_from_user(out, buf, sizeof(*out)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700783 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700784 case IPC_OLD:
785 {
786 struct shmid_ds tbuf_old;
787
788 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
789 return -EFAULT;
790
Pierre Peiffer016d7132008-04-29 01:00:50 -0700791 out->shm_perm.uid = tbuf_old.shm_perm.uid;
792 out->shm_perm.gid = tbuf_old.shm_perm.gid;
793 out->shm_perm.mode = tbuf_old.shm_perm.mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700794
795 return 0;
796 }
797 default:
798 return -EINVAL;
799 }
800}
801
802static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
803{
Manfred Spraul239521f2014-01-27 17:07:04 -0800804 switch (version) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700805 case IPC_64:
806 return copy_to_user(buf, in, sizeof(*in));
807 case IPC_OLD:
808 {
809 struct shminfo out;
810
Manfred Spraul239521f2014-01-27 17:07:04 -0800811 if (in->shmmax > INT_MAX)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700812 out.shmmax = INT_MAX;
813 else
814 out.shmmax = (int)in->shmmax;
815
816 out.shmmin = in->shmmin;
817 out.shmmni = in->shmmni;
818 out.shmseg = in->shmseg;
Paul McQuade46c0a8c2014-06-06 14:37:37 -0700819 out.shmall = in->shmall;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700820
821 return copy_to_user(buf, &out, sizeof(out));
822 }
823 default:
824 return -EINVAL;
825 }
826}
827
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700828/*
Helge Dellerb7952182010-10-27 15:34:16 -0700829 * Calculate and add used RSS and swap pages of a shm.
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700830 * Called with shm_ids.rwsem held as a reader
Helge Dellerb7952182010-10-27 15:34:16 -0700831 */
832static void shm_add_rss_swap(struct shmid_kernel *shp,
833 unsigned long *rss_add, unsigned long *swp_add)
834{
835 struct inode *inode;
836
Al Viro496ad9a2013-01-23 17:07:38 -0500837 inode = file_inode(shp->shm_file);
Helge Dellerb7952182010-10-27 15:34:16 -0700838
839 if (is_file_hugepages(shp->shm_file)) {
840 struct address_space *mapping = inode->i_mapping;
841 struct hstate *h = hstate_file(shp->shm_file);
842 *rss_add += pages_per_huge_page(h) * mapping->nrpages;
843 } else {
844#ifdef CONFIG_SHMEM
845 struct shmem_inode_info *info = SHMEM_I(inode);
Shailesh Pandey63980c82016-12-14 15:06:10 -0800846
Kirill A. Shutemov4595ef82016-07-26 15:26:29 -0700847 spin_lock_irq(&info->lock);
Helge Dellerb7952182010-10-27 15:34:16 -0700848 *rss_add += inode->i_mapping->nrpages;
849 *swp_add += info->swapped;
Kirill A. Shutemov4595ef82016-07-26 15:26:29 -0700850 spin_unlock_irq(&info->lock);
Helge Dellerb7952182010-10-27 15:34:16 -0700851#else
852 *rss_add += inode->i_mapping->nrpages;
853#endif
854 }
855}
856
857/*
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700858 * Called with shm_ids.rwsem held as a reader
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700859 */
Kirill Korotaev4e982312006-10-02 02:18:22 -0700860static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
861 unsigned long *swp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700862{
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700863 int next_id;
864 int total, in_use;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700865
866 *rss = 0;
867 *swp = 0;
868
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700869 in_use = shm_ids(ns).in_use;
870
871 for (total = 0, next_id = 0; total < in_use; next_id++) {
Tony Battersbye562aeb2009-04-02 16:58:26 -0700872 struct kern_ipc_perm *ipc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700873 struct shmid_kernel *shp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700874
Tony Battersbye562aeb2009-04-02 16:58:26 -0700875 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
876 if (ipc == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700877 continue;
Tony Battersbye562aeb2009-04-02 16:58:26 -0700878 shp = container_of(ipc, struct shmid_kernel, shm_perm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879
Helge Dellerb7952182010-10-27 15:34:16 -0700880 shm_add_rss_swap(shp, rss, swp);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700881
882 total++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700883 }
884}
885
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700886/*
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700887 * This function handles some shmctl commands which require the rwsem
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700888 * to be held in write mode.
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700889 * NOTE: no locks must be held, the rwsem is taken inside this function.
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700890 */
891static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
Al Viro9ba720c2017-07-08 20:58:06 -0400892 struct shmid64_ds *shmid64)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700893{
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700894 struct kern_ipc_perm *ipcp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700895 struct shmid_kernel *shp;
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700896 int err;
897
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700898 down_write(&shm_ids(ns).rwsem);
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -0700899 rcu_read_lock();
900
Manfred Spraul4241c1a2018-08-21 22:01:34 -0700901 ipcp = ipcctl_obtain_check(ns, &shm_ids(ns), shmid, cmd,
Al Viro9ba720c2017-07-08 20:58:06 -0400902 &shmid64->shm_perm, 0);
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -0700903 if (IS_ERR(ipcp)) {
904 err = PTR_ERR(ipcp);
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -0700905 goto out_unlock1;
906 }
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700907
Pierre Peiffera5f75e72008-04-29 01:00:54 -0700908 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700909
Eric W. Biederman7191adf2018-03-22 21:08:27 -0500910 err = security_shm_shmctl(&shp->shm_perm, cmd);
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700911 if (err)
Davidlohr Bueso79ccf0f2013-09-11 14:26:16 -0700912 goto out_unlock1;
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -0700913
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700914 switch (cmd) {
915 case IPC_RMID:
Davidlohr Bueso79ccf0f2013-09-11 14:26:16 -0700916 ipc_lock_object(&shp->shm_perm);
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -0700917 /* do_shm_rmid unlocks the ipc object and rcu */
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700918 do_shm_rmid(ns, ipcp);
919 goto out_up;
920 case IPC_SET:
Davidlohr Bueso79ccf0f2013-09-11 14:26:16 -0700921 ipc_lock_object(&shp->shm_perm);
Al Viro9ba720c2017-07-08 20:58:06 -0400922 err = ipc_update_perm(&shmid64->shm_perm, ipcp);
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800923 if (err)
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -0700924 goto out_unlock0;
Deepa Dinamani7ff28192017-08-02 19:51:14 -0700925 shp->shm_ctim = ktime_get_real_seconds();
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700926 break;
927 default:
928 err = -EINVAL;
Davidlohr Bueso79ccf0f2013-09-11 14:26:16 -0700929 goto out_unlock1;
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700930 }
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -0700931
932out_unlock0:
933 ipc_unlock_object(&shp->shm_perm);
934out_unlock1:
935 rcu_read_unlock();
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700936out_up:
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700937 up_write(&shm_ids(ns).rwsem);
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700938 return err;
939}
940
Al Viro9ba720c2017-07-08 20:58:06 -0400941static int shmctl_ipc_info(struct ipc_namespace *ns,
942 struct shminfo64 *shminfo)
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700943{
Al Viro9ba720c2017-07-08 20:58:06 -0400944 int err = security_shm_shmctl(NULL, IPC_INFO);
945 if (!err) {
946 memset(shminfo, 0, sizeof(*shminfo));
947 shminfo->shmmni = shminfo->shmseg = ns->shm_ctlmni;
948 shminfo->shmmax = ns->shm_ctlmax;
949 shminfo->shmall = ns->shm_ctlall;
950 shminfo->shmmin = SHMMIN;
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700951 down_read(&shm_ids(ns).rwsem);
Manfred Spraul27c331a2018-08-21 22:02:00 -0700952 err = ipc_get_maxidx(&shm_ids(ns));
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700953 up_read(&shm_ids(ns).rwsem);
Manfred Spraul239521f2014-01-27 17:07:04 -0800954 if (err < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700955 err = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700956 }
Al Viro9ba720c2017-07-08 20:58:06 -0400957 return err;
958}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700959
Al Viro9ba720c2017-07-08 20:58:06 -0400960static int shmctl_shm_info(struct ipc_namespace *ns,
961 struct shm_info *shm_info)
962{
963 int err = security_shm_shmctl(NULL, SHM_INFO);
964 if (!err) {
965 memset(shm_info, 0, sizeof(*shm_info));
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700966 down_read(&shm_ids(ns).rwsem);
Al Viro9ba720c2017-07-08 20:58:06 -0400967 shm_info->used_ids = shm_ids(ns).in_use;
968 shm_get_stat(ns, &shm_info->shm_rss, &shm_info->shm_swp);
969 shm_info->shm_tot = ns->shm_tot;
970 shm_info->swap_attempts = 0;
971 shm_info->swap_successes = 0;
Manfred Spraul27c331a2018-08-21 22:02:00 -0700972 err = ipc_get_maxidx(&shm_ids(ns));
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700973 up_read(&shm_ids(ns).rwsem);
Al Viro9ba720c2017-07-08 20:58:06 -0400974 if (err < 0)
975 err = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976 }
Al Viro9ba720c2017-07-08 20:58:06 -0400977 return err;
978}
Nadia Derbey023a5352007-10-18 23:40:51 -0700979
Al Viro9ba720c2017-07-08 20:58:06 -0400980static int shmctl_stat(struct ipc_namespace *ns, int shmid,
981 int cmd, struct shmid64_ds *tbuf)
982{
983 struct shmid_kernel *shp;
Al Viro9ba720c2017-07-08 20:58:06 -0400984 int err;
Davidlohr Buesoc97cb9c2013-09-11 14:26:20 -0700985
Philippe Mikoyan87ad4b02018-02-06 15:40:49 -0800986 memset(tbuf, 0, sizeof(*tbuf));
987
Al Viro9ba720c2017-07-08 20:58:06 -0400988 rcu_read_lock();
Davidlohr Buesoc21a6972018-04-10 16:35:23 -0700989 if (cmd == SHM_STAT || cmd == SHM_STAT_ANY) {
Al Viro9ba720c2017-07-08 20:58:06 -0400990 shp = shm_obtain_object(ns, shmid);
991 if (IS_ERR(shp)) {
992 err = PTR_ERR(shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700993 goto out_unlock;
Al Viro9ba720c2017-07-08 20:58:06 -0400994 }
Davidlohr Buesoc21a6972018-04-10 16:35:23 -0700995 } else { /* IPC_STAT */
Al Viro9ba720c2017-07-08 20:58:06 -0400996 shp = shm_obtain_object_check(ns, shmid);
997 if (IS_ERR(shp)) {
998 err = PTR_ERR(shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700999 goto out_unlock;
Al Viro9ba720c2017-07-08 20:58:06 -04001000 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001001 }
Al Viro9ba720c2017-07-08 20:58:06 -04001002
Davidlohr Buesoc21a6972018-04-10 16:35:23 -07001003 /*
1004 * Semantically SHM_STAT_ANY ought to be identical to
1005 * that functionality provided by the /proc/sysvipc/
1006 * interface. As such, only audit these calls and
1007 * do not do traditional S_IRUGO permission checks on
1008 * the ipc object.
1009 */
1010 if (cmd == SHM_STAT_ANY)
1011 audit_ipc_obj(&shp->shm_perm);
1012 else {
1013 err = -EACCES;
1014 if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
1015 goto out_unlock;
1016 }
Al Viro9ba720c2017-07-08 20:58:06 -04001017
Eric W. Biederman7191adf2018-03-22 21:08:27 -05001018 err = security_shm_shmctl(&shp->shm_perm, cmd);
Al Viro9ba720c2017-07-08 20:58:06 -04001019 if (err)
1020 goto out_unlock;
1021
Philippe Mikoyan87ad4b02018-02-06 15:40:49 -08001022 ipc_lock_object(&shp->shm_perm);
1023
1024 if (!ipc_valid_object(&shp->shm_perm)) {
1025 ipc_unlock_object(&shp->shm_perm);
1026 err = -EIDRM;
1027 goto out_unlock;
1028 }
1029
Al Viro9ba720c2017-07-08 20:58:06 -04001030 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf->shm_perm);
1031 tbuf->shm_segsz = shp->shm_segsz;
1032 tbuf->shm_atime = shp->shm_atim;
1033 tbuf->shm_dtime = shp->shm_dtim;
1034 tbuf->shm_ctime = shp->shm_ctim;
Arnd Bergmannc2ab9752015-04-28 21:39:50 +02001035#ifndef CONFIG_64BIT
1036 tbuf->shm_atime_high = shp->shm_atim >> 32;
1037 tbuf->shm_dtime_high = shp->shm_dtim >> 32;
1038 tbuf->shm_ctime_high = shp->shm_ctim >> 32;
1039#endif
Eric W. Biederman98f929b12018-03-23 00:29:57 -05001040 tbuf->shm_cpid = pid_vnr(shp->shm_cprid);
1041 tbuf->shm_lpid = pid_vnr(shp->shm_lprid);
Al Viro9ba720c2017-07-08 20:58:06 -04001042 tbuf->shm_nattch = shp->shm_nattch;
Philippe Mikoyan87ad4b02018-02-06 15:40:49 -08001043
Manfred Spraul615c9992018-08-21 22:01:21 -07001044 if (cmd == IPC_STAT) {
1045 /*
1046 * As defined in SUS:
1047 * Return 0 on success
1048 */
1049 err = 0;
1050 } else {
1051 /*
1052 * SHM_STAT and SHM_STAT_ANY (both Linux specific)
1053 * Return the full id, including the sequence number
1054 */
1055 err = shp->shm_perm.id;
1056 }
Davidlohr Bueso68eccc12013-09-11 14:26:18 -07001057
Manfred Spraul615c9992018-08-21 22:01:21 -07001058 ipc_unlock_object(&shp->shm_perm);
Davidlohr Bueso68eccc12013-09-11 14:26:18 -07001059out_unlock:
Davidlohr Buesoc97cb9c2013-09-11 14:26:20 -07001060 rcu_read_unlock();
Al Viro9ba720c2017-07-08 20:58:06 -04001061 return err;
1062}
1063
1064static int shmctl_do_lock(struct ipc_namespace *ns, int shmid, int cmd)
1065{
1066 struct shmid_kernel *shp;
1067 struct file *shm_file;
1068 int err;
1069
1070 rcu_read_lock();
1071 shp = shm_obtain_object_check(ns, shmid);
1072 if (IS_ERR(shp)) {
1073 err = PTR_ERR(shp);
1074 goto out_unlock1;
1075 }
1076
1077 audit_ipc_obj(&(shp->shm_perm));
Eric W. Biederman7191adf2018-03-22 21:08:27 -05001078 err = security_shm_shmctl(&shp->shm_perm, cmd);
Al Viro9ba720c2017-07-08 20:58:06 -04001079 if (err)
1080 goto out_unlock1;
1081
1082 ipc_lock_object(&shp->shm_perm);
1083
1084 /* check if shm_destroy() is tearing down shp */
1085 if (!ipc_valid_object(&shp->shm_perm)) {
1086 err = -EIDRM;
1087 goto out_unlock0;
1088 }
1089
1090 if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
1091 kuid_t euid = current_euid();
1092
1093 if (!uid_eq(euid, shp->shm_perm.uid) &&
1094 !uid_eq(euid, shp->shm_perm.cuid)) {
1095 err = -EPERM;
1096 goto out_unlock0;
1097 }
1098 if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) {
1099 err = -EPERM;
1100 goto out_unlock0;
1101 }
1102 }
1103
1104 shm_file = shp->shm_file;
1105 if (is_file_hugepages(shm_file))
1106 goto out_unlock0;
1107
1108 if (cmd == SHM_LOCK) {
1109 struct user_struct *user = current_user();
1110
1111 err = shmem_lock(shm_file, 1, user);
1112 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
1113 shp->shm_perm.mode |= SHM_LOCKED;
1114 shp->mlock_user = user;
1115 }
1116 goto out_unlock0;
1117 }
1118
1119 /* SHM_UNLOCK */
1120 if (!(shp->shm_perm.mode & SHM_LOCKED))
1121 goto out_unlock0;
1122 shmem_lock(shm_file, 0, shp->mlock_user);
1123 shp->shm_perm.mode &= ~SHM_LOCKED;
1124 shp->mlock_user = NULL;
1125 get_file(shm_file);
1126 ipc_unlock_object(&shp->shm_perm);
1127 rcu_read_unlock();
1128 shmem_unlock_mapping(shm_file->f_mapping);
1129
1130 fput(shm_file);
1131 return err;
1132
1133out_unlock0:
1134 ipc_unlock_object(&shp->shm_perm);
1135out_unlock1:
1136 rcu_read_unlock();
Davidlohr Bueso68eccc12013-09-11 14:26:18 -07001137 return err;
1138}
1139
Dominik Brodowskic84d0792018-03-20 20:12:33 +01001140long ksys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf)
Davidlohr Bueso68eccc12013-09-11 14:26:18 -07001141{
Davidlohr Bueso68eccc12013-09-11 14:26:18 -07001142 int err, version;
1143 struct ipc_namespace *ns;
Al Viro553f7702017-07-08 22:52:47 -04001144 struct shmid64_ds sem64;
Davidlohr Bueso68eccc12013-09-11 14:26:18 -07001145
Davidlohr Bueso2caacaa2013-09-11 14:26:21 -07001146 if (cmd < 0 || shmid < 0)
1147 return -EINVAL;
Davidlohr Bueso68eccc12013-09-11 14:26:18 -07001148
1149 version = ipc_parse_version(&cmd);
1150 ns = current->nsproxy->ipc_ns;
1151
1152 switch (cmd) {
Al Viro9ba720c2017-07-08 20:58:06 -04001153 case IPC_INFO: {
1154 struct shminfo64 shminfo;
1155 err = shmctl_ipc_info(ns, &shminfo);
1156 if (err < 0)
1157 return err;
1158 if (copy_shminfo_to_user(buf, &shminfo, version))
1159 err = -EFAULT;
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -07001160 return err;
Davidlohr Bueso2caacaa2013-09-11 14:26:21 -07001161 }
Al Viro9ba720c2017-07-08 20:58:06 -04001162 case SHM_INFO: {
1163 struct shm_info shm_info;
1164 err = shmctl_shm_info(ns, &shm_info);
1165 if (err < 0)
1166 return err;
1167 if (copy_to_user(buf, &shm_info, sizeof(shm_info)))
1168 err = -EFAULT;
1169 return err;
1170 }
1171 case SHM_STAT:
Davidlohr Buesoc21a6972018-04-10 16:35:23 -07001172 case SHM_STAT_ANY:
Al Viro9ba720c2017-07-08 20:58:06 -04001173 case IPC_STAT: {
Al Viro553f7702017-07-08 22:52:47 -04001174 err = shmctl_stat(ns, shmid, cmd, &sem64);
Al Viro9ba720c2017-07-08 20:58:06 -04001175 if (err < 0)
1176 return err;
Al Viro553f7702017-07-08 22:52:47 -04001177 if (copy_shmid_to_user(buf, &sem64, version))
Al Viro9ba720c2017-07-08 20:58:06 -04001178 err = -EFAULT;
1179 return err;
1180 }
1181 case IPC_SET:
Al Viro553f7702017-07-08 22:52:47 -04001182 if (copy_shmid_from_user(&sem64, buf, version))
Al Viro9ba720c2017-07-08 20:58:06 -04001183 return -EFAULT;
Al Viro553f7702017-07-08 22:52:47 -04001184 /* fallthru */
Al Viro9ba720c2017-07-08 20:58:06 -04001185 case IPC_RMID:
Al Viro553f7702017-07-08 22:52:47 -04001186 return shmctl_down(ns, shmid, cmd, &sem64);
Al Viro9ba720c2017-07-08 20:58:06 -04001187 case SHM_LOCK:
1188 case SHM_UNLOCK:
1189 return shmctl_do_lock(ns, shmid, cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001190 default:
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -07001191 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001192 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001193}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001194
Dominik Brodowskic84d0792018-03-20 20:12:33 +01001195SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
1196{
1197 return ksys_shmctl(shmid, cmd, buf);
1198}
1199
Al Viro553f7702017-07-08 22:52:47 -04001200#ifdef CONFIG_COMPAT
1201
1202struct compat_shmid_ds {
1203 struct compat_ipc_perm shm_perm;
1204 int shm_segsz;
Arnd Bergmann9afc5ee2018-07-13 12:52:28 +02001205 old_time32_t shm_atime;
1206 old_time32_t shm_dtime;
1207 old_time32_t shm_ctime;
Al Viro553f7702017-07-08 22:52:47 -04001208 compat_ipc_pid_t shm_cpid;
1209 compat_ipc_pid_t shm_lpid;
1210 unsigned short shm_nattch;
1211 unsigned short shm_unused;
1212 compat_uptr_t shm_unused2;
1213 compat_uptr_t shm_unused3;
1214};
1215
1216struct compat_shminfo64 {
1217 compat_ulong_t shmmax;
1218 compat_ulong_t shmmin;
1219 compat_ulong_t shmmni;
1220 compat_ulong_t shmseg;
1221 compat_ulong_t shmall;
1222 compat_ulong_t __unused1;
1223 compat_ulong_t __unused2;
1224 compat_ulong_t __unused3;
1225 compat_ulong_t __unused4;
1226};
1227
1228struct compat_shm_info {
1229 compat_int_t used_ids;
1230 compat_ulong_t shm_tot, shm_rss, shm_swp;
1231 compat_ulong_t swap_attempts, swap_successes;
1232};
1233
1234static int copy_compat_shminfo_to_user(void __user *buf, struct shminfo64 *in,
1235 int version)
1236{
1237 if (in->shmmax > INT_MAX)
1238 in->shmmax = INT_MAX;
1239 if (version == IPC_64) {
1240 struct compat_shminfo64 info;
1241 memset(&info, 0, sizeof(info));
1242 info.shmmax = in->shmmax;
1243 info.shmmin = in->shmmin;
1244 info.shmmni = in->shmmni;
1245 info.shmseg = in->shmseg;
1246 info.shmall = in->shmall;
1247 return copy_to_user(buf, &info, sizeof(info));
1248 } else {
1249 struct shminfo info;
1250 memset(&info, 0, sizeof(info));
1251 info.shmmax = in->shmmax;
1252 info.shmmin = in->shmmin;
1253 info.shmmni = in->shmmni;
1254 info.shmseg = in->shmseg;
1255 info.shmall = in->shmall;
1256 return copy_to_user(buf, &info, sizeof(info));
1257 }
1258}
1259
1260static int put_compat_shm_info(struct shm_info *ip,
1261 struct compat_shm_info __user *uip)
1262{
1263 struct compat_shm_info info;
1264
1265 memset(&info, 0, sizeof(info));
1266 info.used_ids = ip->used_ids;
1267 info.shm_tot = ip->shm_tot;
1268 info.shm_rss = ip->shm_rss;
1269 info.shm_swp = ip->shm_swp;
1270 info.swap_attempts = ip->swap_attempts;
1271 info.swap_successes = ip->swap_successes;
Al Virob776e4b2017-09-25 20:38:45 -04001272 return copy_to_user(uip, &info, sizeof(info));
Al Viro553f7702017-07-08 22:52:47 -04001273}
1274
1275static int copy_compat_shmid_to_user(void __user *buf, struct shmid64_ds *in,
1276 int version)
1277{
1278 if (version == IPC_64) {
1279 struct compat_shmid64_ds v;
1280 memset(&v, 0, sizeof(v));
Al Viro28327fa2017-07-09 10:10:32 -04001281 to_compat_ipc64_perm(&v.shm_perm, &in->shm_perm);
Arnd Bergmannc2ab9752015-04-28 21:39:50 +02001282 v.shm_atime = lower_32_bits(in->shm_atime);
1283 v.shm_atime_high = upper_32_bits(in->shm_atime);
1284 v.shm_dtime = lower_32_bits(in->shm_dtime);
1285 v.shm_dtime_high = upper_32_bits(in->shm_dtime);
1286 v.shm_ctime = lower_32_bits(in->shm_ctime);
1287 v.shm_ctime_high = upper_32_bits(in->shm_ctime);
Al Viro553f7702017-07-08 22:52:47 -04001288 v.shm_segsz = in->shm_segsz;
1289 v.shm_nattch = in->shm_nattch;
1290 v.shm_cpid = in->shm_cpid;
1291 v.shm_lpid = in->shm_lpid;
1292 return copy_to_user(buf, &v, sizeof(v));
1293 } else {
1294 struct compat_shmid_ds v;
1295 memset(&v, 0, sizeof(v));
Al Viro28327fa2017-07-09 10:10:32 -04001296 to_compat_ipc_perm(&v.shm_perm, &in->shm_perm);
Al Viro553f7702017-07-08 22:52:47 -04001297 v.shm_perm.key = in->shm_perm.key;
Al Viro553f7702017-07-08 22:52:47 -04001298 v.shm_atime = in->shm_atime;
1299 v.shm_dtime = in->shm_dtime;
1300 v.shm_ctime = in->shm_ctime;
1301 v.shm_segsz = in->shm_segsz;
1302 v.shm_nattch = in->shm_nattch;
1303 v.shm_cpid = in->shm_cpid;
1304 v.shm_lpid = in->shm_lpid;
1305 return copy_to_user(buf, &v, sizeof(v));
1306 }
1307}
1308
1309static int copy_compat_shmid_from_user(struct shmid64_ds *out, void __user *buf,
1310 int version)
1311{
1312 memset(out, 0, sizeof(*out));
1313 if (version == IPC_64) {
Linus Torvalds6aa211e2017-09-25 18:37:28 -07001314 struct compat_shmid64_ds __user *p = buf;
Al Viro28327fa2017-07-09 10:10:32 -04001315 return get_compat_ipc64_perm(&out->shm_perm, &p->shm_perm);
Al Viro553f7702017-07-08 22:52:47 -04001316 } else {
Linus Torvalds6aa211e2017-09-25 18:37:28 -07001317 struct compat_shmid_ds __user *p = buf;
Al Viro28327fa2017-07-09 10:10:32 -04001318 return get_compat_ipc_perm(&out->shm_perm, &p->shm_perm);
Al Viro553f7702017-07-08 22:52:47 -04001319 }
Al Viro553f7702017-07-08 22:52:47 -04001320}
1321
Dominik Brodowskic84d0792018-03-20 20:12:33 +01001322long compat_ksys_shmctl(int shmid, int cmd, void __user *uptr)
Al Viro553f7702017-07-08 22:52:47 -04001323{
1324 struct ipc_namespace *ns;
1325 struct shmid64_ds sem64;
1326 int version = compat_ipc_parse_version(&cmd);
1327 int err;
1328
1329 ns = current->nsproxy->ipc_ns;
1330
1331 if (cmd < 0 || shmid < 0)
1332 return -EINVAL;
1333
1334 switch (cmd) {
1335 case IPC_INFO: {
1336 struct shminfo64 shminfo;
1337 err = shmctl_ipc_info(ns, &shminfo);
1338 if (err < 0)
1339 return err;
1340 if (copy_compat_shminfo_to_user(uptr, &shminfo, version))
1341 err = -EFAULT;
1342 return err;
1343 }
1344 case SHM_INFO: {
1345 struct shm_info shm_info;
1346 err = shmctl_shm_info(ns, &shm_info);
1347 if (err < 0)
1348 return err;
1349 if (put_compat_shm_info(&shm_info, uptr))
1350 err = -EFAULT;
1351 return err;
1352 }
1353 case IPC_STAT:
Davidlohr Buesoc21a6972018-04-10 16:35:23 -07001354 case SHM_STAT_ANY:
Al Viro553f7702017-07-08 22:52:47 -04001355 case SHM_STAT:
1356 err = shmctl_stat(ns, shmid, cmd, &sem64);
1357 if (err < 0)
1358 return err;
Will Deacon58aff0a2017-09-18 17:47:38 +01001359 if (copy_compat_shmid_to_user(uptr, &sem64, version))
Al Viro553f7702017-07-08 22:52:47 -04001360 err = -EFAULT;
1361 return err;
1362
1363 case IPC_SET:
1364 if (copy_compat_shmid_from_user(&sem64, uptr, version))
1365 return -EFAULT;
1366 /* fallthru */
1367 case IPC_RMID:
1368 return shmctl_down(ns, shmid, cmd, &sem64);
1369 case SHM_LOCK:
1370 case SHM_UNLOCK:
1371 return shmctl_do_lock(ns, shmid, cmd);
1372 break;
1373 default:
1374 return -EINVAL;
1375 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001376 return err;
1377}
Dominik Brodowskic84d0792018-03-20 20:12:33 +01001378
1379COMPAT_SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, void __user *, uptr)
1380{
1381 return compat_ksys_shmctl(shmid, cmd, uptr);
1382}
Al Viro553f7702017-07-08 22:52:47 -04001383#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07001384
1385/*
1386 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
1387 *
1388 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
1389 * "raddr" thing points to kernel space, and there has to be a wrapper around
1390 * this.
1391 */
Davidlohr Bueso95e91b82017-02-27 14:28:24 -08001392long do_shmat(int shmid, char __user *shmaddr, int shmflg,
1393 ulong *raddr, unsigned long shmlba)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001394{
1395 struct shmid_kernel *shp;
Davidlohr Buesof0cb8802017-05-08 15:57:03 -07001396 unsigned long addr = (unsigned long)shmaddr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001397 unsigned long size;
Al Viro4f089ac2018-06-17 12:24:00 -04001398 struct file *file, *base;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001399 int err;
Davidlohr Buesof0cb8802017-05-08 15:57:03 -07001400 unsigned long flags = MAP_SHARED;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001401 unsigned long prot;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001402 int acc_mode;
Kirill Korotaev4e982312006-10-02 02:18:22 -07001403 struct ipc_namespace *ns;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001404 struct shm_file_data *sfd;
Al Viroc9c554f2018-07-11 14:19:04 -04001405 int f_flags;
Michel Lespinasse41badc12013-02-22 16:32:47 -08001406 unsigned long populate = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001407
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001408 err = -EINVAL;
1409 if (shmid < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001410 goto out;
Davidlohr Buesof0cb8802017-05-08 15:57:03 -07001411
1412 if (addr) {
Will Deacon079a96a2012-07-30 14:42:38 -07001413 if (addr & (shmlba - 1)) {
Davidlohr Bueso8f89c002018-05-25 14:47:30 -07001414 if (shmflg & SHM_RND) {
Davidlohr Buesoa73ab242018-05-25 14:47:27 -07001415 addr &= ~(shmlba - 1); /* round down */
Davidlohr Bueso8f89c002018-05-25 14:47:30 -07001416
1417 /*
1418 * Ensure that the round-down is non-nil
1419 * when remapping. This can happen for
1420 * cases when addr < shmlba.
1421 */
1422 if (!addr && (shmflg & SHM_REMAP))
1423 goto out;
1424 } else
Linus Torvalds1da177e2005-04-16 15:20:36 -07001425#ifndef __ARCH_FORCE_SHMLBA
1426 if (addr & ~PAGE_MASK)
1427#endif
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001428 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001429 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001430
Davidlohr Buesof0cb8802017-05-08 15:57:03 -07001431 flags |= MAP_FIXED;
1432 } else if ((shmflg & SHM_REMAP))
1433 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001434
1435 if (shmflg & SHM_RDONLY) {
1436 prot = PROT_READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001437 acc_mode = S_IRUGO;
Al Viroc9c554f2018-07-11 14:19:04 -04001438 f_flags = O_RDONLY;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001439 } else {
1440 prot = PROT_READ | PROT_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001441 acc_mode = S_IRUGO | S_IWUGO;
Al Viroc9c554f2018-07-11 14:19:04 -04001442 f_flags = O_RDWR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001443 }
1444 if (shmflg & SHM_EXEC) {
1445 prot |= PROT_EXEC;
1446 acc_mode |= S_IXUGO;
1447 }
1448
1449 /*
1450 * We cannot rely on the fs check since SYSV IPC does have an
1451 * additional creator id...
1452 */
Kirill Korotaev4e982312006-10-02 02:18:22 -07001453 ns = current->nsproxy->ipc_ns;
Davidlohr Buesoc2c737a2013-09-11 14:26:23 -07001454 rcu_read_lock();
1455 shp = shm_obtain_object_check(ns, shmid);
Nadia Derbey023a5352007-10-18 23:40:51 -07001456 if (IS_ERR(shp)) {
1457 err = PTR_ERR(shp);
Davidlohr Buesoc2c737a2013-09-11 14:26:23 -07001458 goto out_unlock;
Nadia Derbey023a5352007-10-18 23:40:51 -07001459 }
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001460
1461 err = -EACCES;
Serge E. Hallynb0e77592011-03-23 16:43:24 -07001462 if (ipcperms(ns, &shp->shm_perm, acc_mode))
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001463 goto out_unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001464
Eric W. Biederman7191adf2018-03-22 21:08:27 -05001465 err = security_shm_shmat(&shp->shm_perm, shmaddr, shmflg);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001466 if (err)
1467 goto out_unlock;
1468
Davidlohr Buesoc2c737a2013-09-11 14:26:23 -07001469 ipc_lock_object(&shp->shm_perm);
Greg Thelena399b292013-11-21 14:32:00 -08001470
1471 /* check if shm_destroy() is tearing down shp */
Rafael Aquini0f3d2b02014-01-27 17:07:01 -08001472 if (!ipc_valid_object(&shp->shm_perm)) {
Greg Thelena399b292013-11-21 14:32:00 -08001473 ipc_unlock_object(&shp->shm_perm);
1474 err = -EIDRM;
1475 goto out_unlock;
1476 }
1477
Eric Biggers3f053172018-04-13 15:35:30 -07001478 /*
1479 * We need to take a reference to the real shm file to prevent the
1480 * pointer from becoming stale in cases where the lifetime of the outer
1481 * file extends beyond that of the shm segment. It's not usually
1482 * possible, but it can happen during remap_file_pages() emulation as
1483 * that unmaps the memory, then does ->mmap() via file reference only.
1484 * We'll deny the ->mmap() if the shm segment was since removed, but to
1485 * detect shm ID reuse we need to compare the file pointers.
1486 */
Al Viro4f089ac2018-06-17 12:24:00 -04001487 base = get_file(shp->shm_file);
1488 shp->shm_nattch++;
1489 size = i_size_read(file_inode(base));
1490 ipc_unlock_object(&shp->shm_perm);
1491 rcu_read_unlock();
1492
1493 err = -ENOMEM;
1494 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
1495 if (!sfd) {
1496 fput(base);
1497 goto out_nattch;
1498 }
1499
1500 file = alloc_file_clone(base, f_flags,
1501 is_file_hugepages(base) ?
1502 &shm_file_operations_huge :
1503 &shm_file_operations);
1504 err = PTR_ERR(file);
1505 if (IS_ERR(file)) {
1506 kfree(sfd);
1507 fput(base);
1508 goto out_nattch;
1509 }
1510
1511 sfd->id = shp->shm_perm.id;
1512 sfd->ns = get_ipc_ns(ns);
1513 sfd->file = base;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001514 sfd->vm_ops = NULL;
Al Viro4f089ac2018-06-17 12:24:00 -04001515 file->private_data = sfd;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001516
Al Viro8b3ec682012-05-30 17:11:23 -04001517 err = security_mmap_file(file, prot, flags);
1518 if (err)
1519 goto out_fput;
1520
Michal Hocko91f4f942016-05-23 16:25:51 -07001521 if (down_write_killable(&current->mm->mmap_sem)) {
1522 err = -EINTR;
1523 goto out_fput;
1524 }
1525
Linus Torvalds1da177e2005-04-16 15:20:36 -07001526 if (addr && !(shmflg & SHM_REMAP)) {
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001527 err = -EINVAL;
Manfred Spraul247a8ce2014-06-06 14:37:38 -07001528 if (addr + size < addr)
1529 goto invalid;
1530
Linus Torvalds1da177e2005-04-16 15:20:36 -07001531 if (find_vma_intersection(current->mm, addr, addr + size))
1532 goto invalid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001533 }
Davidlohr Buesof42569b2013-09-11 14:26:22 -07001534
Mike Rapoport897ab3e2017-02-24 14:58:22 -08001535 addr = do_mmap_pgoff(file, addr, size, prot, flags, 0, &populate, NULL);
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001536 *raddr = addr;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001537 err = 0;
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001538 if (IS_ERR_VALUE(addr))
1539 err = (long)addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001540invalid:
1541 up_write(&current->mm->mmap_sem);
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001542 if (populate)
Michel Lespinasse41badc12013-02-22 16:32:47 -08001543 mm_populate(addr, populate);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001544
Al Viro8b3ec682012-05-30 17:11:23 -04001545out_fput:
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001546 fput(file);
1547
1548out_nattch:
Davidlohr Buesod9a605e2013-09-11 14:26:24 -07001549 down_write(&shm_ids(ns).rwsem);
Nadia Derbey00c2bf82008-07-25 01:48:03 -07001550 shp = shm_lock(ns, shmid);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001551 shp->shm_nattch--;
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -07001552 if (shm_may_destroy(ns, shp))
Kirill Korotaev4e982312006-10-02 02:18:22 -07001553 shm_destroy(ns, shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001554 else
1555 shm_unlock(shp);
Davidlohr Buesod9a605e2013-09-11 14:26:24 -07001556 up_write(&shm_ids(ns).rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001557 return err;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001558
1559out_unlock:
Davidlohr Buesoc2c737a2013-09-11 14:26:23 -07001560 rcu_read_unlock();
Davidlohr Buesof42569b2013-09-11 14:26:22 -07001561out:
1562 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001563}
1564
Heiko Carstensd5460c92009-01-14 14:14:27 +01001565SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
Stephen Rothwell7d87e14c2005-05-01 08:59:12 -07001566{
1567 unsigned long ret;
1568 long err;
1569
Will Deacon079a96a2012-07-30 14:42:38 -07001570 err = do_shmat(shmid, shmaddr, shmflg, &ret, SHMLBA);
Stephen Rothwell7d87e14c2005-05-01 08:59:12 -07001571 if (err)
1572 return err;
1573 force_successful_syscall_return();
1574 return (long)ret;
1575}
1576
Al Viroa78ee9e2017-07-09 10:38:28 -04001577#ifdef CONFIG_COMPAT
1578
1579#ifndef COMPAT_SHMLBA
1580#define COMPAT_SHMLBA SHMLBA
1581#endif
1582
1583COMPAT_SYSCALL_DEFINE3(shmat, int, shmid, compat_uptr_t, shmaddr, int, shmflg)
1584{
1585 unsigned long ret;
1586 long err;
1587
1588 err = do_shmat(shmid, compat_ptr(shmaddr), shmflg, &ret, COMPAT_SHMLBA);
1589 if (err)
1590 return err;
1591 force_successful_syscall_return();
1592 return (long)ret;
1593}
1594#endif
1595
Linus Torvalds1da177e2005-04-16 15:20:36 -07001596/*
1597 * detach and kill segment if marked destroyed.
1598 * The work is done in shm_close.
1599 */
Dominik Brodowskida1e27442018-03-20 20:09:48 +01001600long ksys_shmdt(char __user *shmaddr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001601{
1602 struct mm_struct *mm = current->mm;
Mike Frysinger586c7e62009-06-09 16:26:23 -07001603 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001604 unsigned long addr = (unsigned long)shmaddr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001605 int retval = -EINVAL;
Mike Frysinger586c7e62009-06-09 16:26:23 -07001606#ifdef CONFIG_MMU
1607 loff_t size = 0;
Dave Hansend3c97902014-12-12 16:58:19 -08001608 struct file *file;
Mike Frysinger586c7e62009-06-09 16:26:23 -07001609 struct vm_area_struct *next;
1610#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07001611
Hugh Dickinsdf1e2fb2006-03-24 03:18:06 -08001612 if (addr & ~PAGE_MASK)
1613 return retval;
1614
Michal Hocko91f4f942016-05-23 16:25:51 -07001615 if (down_write_killable(&mm->mmap_sem))
1616 return -EINTR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001617
1618 /*
1619 * This function tries to be smart and unmap shm segments that
1620 * were modified by partial mlock or munmap calls:
1621 * - It first determines the size of the shm segment that should be
1622 * unmapped: It searches for a vma that is backed by shm and that
1623 * started at address shmaddr. It records it's size and then unmaps
1624 * it.
1625 * - Then it unmaps all shm vmas that started at shmaddr and that
Dave Hansend3c97902014-12-12 16:58:19 -08001626 * are within the initially determined size and that are from the
1627 * same shm segment from which we determined the size.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001628 * Errors from do_munmap are ignored: the function only fails if
1629 * it's called with invalid parameters or if it's called to unmap
1630 * a part of a vma. Both calls in this function are for full vmas,
1631 * the parameters are directly copied from the vma itself and always
1632 * valid - therefore do_munmap cannot fail. (famous last words?)
1633 */
1634 /*
1635 * If it had been mremap()'d, the starting address would not
1636 * match the usual checks anyway. So assume all vma's are
1637 * above the starting address given.
1638 */
1639 vma = find_vma(mm, addr);
1640
David Howells8feae132009-01-08 12:04:47 +00001641#ifdef CONFIG_MMU
Linus Torvalds1da177e2005-04-16 15:20:36 -07001642 while (vma) {
1643 next = vma->vm_next;
1644
1645 /*
1646 * Check if the starting address would match, i.e. it's
1647 * a fragment created by mprotect() and/or munmap(), or it
1648 * otherwise it starts at this address with no hassles.
1649 */
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001650 if ((vma->vm_ops == &shm_vm_ops) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -07001651 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1652
Dave Hansend3c97902014-12-12 16:58:19 -08001653 /*
1654 * Record the file of the shm segment being
1655 * unmapped. With mremap(), someone could place
1656 * page from another segment but with equal offsets
1657 * in the range we are unmapping.
1658 */
1659 file = vma->vm_file;
Dave Hansen07a46ed2014-12-12 16:58:22 -08001660 size = i_size_read(file_inode(vma->vm_file));
Mike Rapoport897ab3e2017-02-24 14:58:22 -08001661 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001662 /*
1663 * We discovered the size of the shm segment, so
1664 * break out of here and fall through to the next
1665 * loop that uses the size information to stop
1666 * searching for matching vma's.
1667 */
1668 retval = 0;
1669 vma = next;
1670 break;
1671 }
1672 vma = next;
1673 }
1674
1675 /*
1676 * We need look no further than the maximum address a fragment
1677 * could possibly have landed at. Also cast things to loff_t to
Lucas De Marchi25985ed2011-03-30 22:57:33 -03001678 * prevent overflows and make comparisons vs. equal-width types.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001679 */
KAMEZAWA Hiroyuki8e367092006-02-10 01:51:12 -08001680 size = PAGE_ALIGN(size);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001681 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1682 next = vma->vm_next;
1683
1684 /* finding a matching vma now does not alter retval */
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001685 if ((vma->vm_ops == &shm_vm_ops) &&
Dave Hansend3c97902014-12-12 16:58:19 -08001686 ((vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) &&
1687 (vma->vm_file == file))
Mike Rapoport897ab3e2017-02-24 14:58:22 -08001688 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001689 vma = next;
1690 }
1691
Shailesh Pandey63980c82016-12-14 15:06:10 -08001692#else /* CONFIG_MMU */
David Howells8feae132009-01-08 12:04:47 +00001693 /* under NOMMU conditions, the exact address to be destroyed must be
Shailesh Pandey63980c82016-12-14 15:06:10 -08001694 * given
1695 */
Davidlohr Bueso530fcd162013-09-11 14:26:28 -07001696 if (vma && vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
Mike Rapoport897ab3e2017-02-24 14:58:22 -08001697 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start, NULL);
David Howells8feae132009-01-08 12:04:47 +00001698 retval = 0;
1699 }
1700
1701#endif
1702
Linus Torvalds1da177e2005-04-16 15:20:36 -07001703 up_write(&mm->mmap_sem);
1704 return retval;
1705}
1706
Dominik Brodowskida1e27442018-03-20 20:09:48 +01001707SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
1708{
1709 return ksys_shmdt(shmaddr);
1710}
1711
Linus Torvalds1da177e2005-04-16 15:20:36 -07001712#ifdef CONFIG_PROC_FS
Mike Waychison19b49462005-09-06 15:17:10 -07001713static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001714{
Eric W. Biederman98f929b12018-03-23 00:29:57 -05001715 struct pid_namespace *pid_ns = ipc_seq_pid_ns(s);
Eric W. Biederman1efdb692012-02-07 16:54:11 -08001716 struct user_namespace *user_ns = seq_user_ns(s);
Kees Cookade9f912017-08-02 13:32:21 -07001717 struct kern_ipc_perm *ipcp = it;
1718 struct shmid_kernel *shp;
Helge Dellerb7952182010-10-27 15:34:16 -07001719 unsigned long rss = 0, swp = 0;
1720
Kees Cookade9f912017-08-02 13:32:21 -07001721 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
Helge Dellerb7952182010-10-27 15:34:16 -07001722 shm_add_rss_swap(shp, &rss, &swp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001723
Paul Menage6c826812008-06-12 15:21:49 -07001724#if BITS_PER_LONG <= 32
1725#define SIZE_SPEC "%10lu"
1726#else
1727#define SIZE_SPEC "%21lu"
1728#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07001729
Joe Perches7f032d62015-04-15 16:17:54 -07001730 seq_printf(s,
1731 "%10d %10d %4o " SIZE_SPEC " %5u %5u "
Deepa Dinamani7ff28192017-08-02 19:51:14 -07001732 "%5lu %5u %5u %5u %5u %10llu %10llu %10llu "
Joe Perches7f032d62015-04-15 16:17:54 -07001733 SIZE_SPEC " " SIZE_SPEC "\n",
1734 shp->shm_perm.key,
1735 shp->shm_perm.id,
1736 shp->shm_perm.mode,
1737 shp->shm_segsz,
Eric W. Biederman98f929b12018-03-23 00:29:57 -05001738 pid_nr_ns(shp->shm_cprid, pid_ns),
1739 pid_nr_ns(shp->shm_lprid, pid_ns),
Joe Perches7f032d62015-04-15 16:17:54 -07001740 shp->shm_nattch,
1741 from_kuid_munged(user_ns, shp->shm_perm.uid),
1742 from_kgid_munged(user_ns, shp->shm_perm.gid),
1743 from_kuid_munged(user_ns, shp->shm_perm.cuid),
1744 from_kgid_munged(user_ns, shp->shm_perm.cgid),
1745 shp->shm_atim,
1746 shp->shm_dtim,
1747 shp->shm_ctim,
1748 rss * PAGE_SIZE,
1749 swp * PAGE_SIZE);
1750
1751 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001752}
1753#endif