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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/ipc/shm.c
3 * Copyright (C) 1992, 1993 Krishna Balasubramanian
4 * Many improvements/fixes by Bruno Haible.
5 * Replaced `struct shm_desc' by `struct vm_area_struct', July 1994.
6 * Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli.
7 *
8 * /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
9 * BIGMEM support, Andrea Arcangeli <andrea@suse.de>
10 * SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr>
11 * HIGHMEM support, Ingo Molnar <mingo@redhat.com>
12 * Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <cr@sap.com>
13 * Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com>
14 * Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com>
15 *
Steve Grubb073115d2006-04-02 17:07:33 -040016 * support for audit of ipc object properties and permission changes
17 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
Kirill Korotaev4e982312006-10-02 02:18:22 -070018 *
19 * namespaces support
20 * OpenVZ, SWsoft Inc.
21 * Pavel Emelianov <xemul@openvz.org>
Davidlohr Buesoc2c737a2013-09-11 14:26:23 -070022 *
23 * Better ipc lock (kern_ipc_perm.lock) handling
24 * Davidlohr Bueso <davidlohr.bueso@hp.com>, June 2013.
Linus Torvalds1da177e2005-04-16 15:20:36 -070025 */
26
Linus Torvalds1da177e2005-04-16 15:20:36 -070027#include <linux/slab.h>
28#include <linux/mm.h>
29#include <linux/hugetlb.h>
30#include <linux/shm.h>
31#include <linux/init.h>
32#include <linux/file.h>
33#include <linux/mman.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070034#include <linux/shmem_fs.h>
35#include <linux/security.h>
36#include <linux/syscalls.h>
37#include <linux/audit.h>
Randy.Dunlapc59ede72006-01-11 12:17:46 -080038#include <linux/capability.h>
Stephen Rothwell7d87e14c2005-05-01 08:59:12 -070039#include <linux/ptrace.h>
Mike Waychison19b49462005-09-06 15:17:10 -070040#include <linux/seq_file.h>
Nadia Derbey3e148c72007-10-18 23:40:54 -070041#include <linux/rwsem.h>
Kirill Korotaev4e982312006-10-02 02:18:22 -070042#include <linux/nsproxy.h>
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -080043#include <linux/mount.h>
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -080044#include <linux/ipc_namespace.h>
Stephen Rothwell7d87e14c2005-05-01 08:59:12 -070045
Paul McQuade7153e402014-06-06 14:37:37 -070046#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070047
48#include "util.h"
49
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -080050struct shm_file_data {
51 int id;
52 struct ipc_namespace *ns;
53 struct file *file;
54 const struct vm_operations_struct *vm_ops;
55};
56
57#define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
58
Arjan van de Ven9a321442007-02-12 00:55:35 -080059static const struct file_operations shm_file_operations;
Alexey Dobriyanf0f37e22009-09-27 22:29:37 +040060static const struct vm_operations_struct shm_vm_ops;
Linus Torvalds1da177e2005-04-16 15:20:36 -070061
Pierre Peiffered2ddbf2008-02-08 04:18:57 -080062#define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS])
Linus Torvalds1da177e2005-04-16 15:20:36 -070063
Kirill Korotaev4e982312006-10-02 02:18:22 -070064#define shm_unlock(shp) \
65 ipc_unlock(&(shp)->shm_perm)
Kirill Korotaev4e982312006-10-02 02:18:22 -070066
Nadia Derbey7748dbf2007-10-18 23:40:49 -070067static int newseg(struct ipc_namespace *, struct ipc_params *);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -080068static void shm_open(struct vm_area_struct *vma);
69static void shm_close(struct vm_area_struct *vma);
Manfred Spraul239521f2014-01-27 17:07:04 -080070static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -070071#ifdef CONFIG_PROC_FS
Mike Waychison19b49462005-09-06 15:17:10 -070072static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
Linus Torvalds1da177e2005-04-16 15:20:36 -070073#endif
74
Pierre Peiffered2ddbf2008-02-08 04:18:57 -080075void shm_init_ns(struct ipc_namespace *ns)
Kirill Korotaev4e982312006-10-02 02:18:22 -070076{
Kirill Korotaev4e982312006-10-02 02:18:22 -070077 ns->shm_ctlmax = SHMMAX;
78 ns->shm_ctlall = SHMALL;
79 ns->shm_ctlmni = SHMMNI;
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -070080 ns->shm_rmid_forced = 0;
Kirill Korotaev4e982312006-10-02 02:18:22 -070081 ns->shm_tot = 0;
WANG Conge8148f72009-01-06 14:42:49 -080082 ipc_init_ids(&shm_ids(ns));
Kirill Korotaev4e982312006-10-02 02:18:22 -070083}
Linus Torvalds1da177e2005-04-16 15:20:36 -070084
Nadia Derbeyf4566f02007-10-18 23:40:53 -070085/*
Davidlohr Buesod9a605e2013-09-11 14:26:24 -070086 * Called with shm_ids.rwsem (writer) and the shp structure locked.
87 * Only shm_ids.rwsem remains locked on exit.
Nadia Derbeyf4566f02007-10-18 23:40:53 -070088 */
Pierre Peiffer01b8b072008-02-08 04:18:57 -080089static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
Kirill Korotaev4e982312006-10-02 02:18:22 -070090{
Pierre Peiffer01b8b072008-02-08 04:18:57 -080091 struct shmid_kernel *shp;
92 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
93
Manfred Spraul239521f2014-01-27 17:07:04 -080094 if (shp->shm_nattch) {
Kirill Korotaev4e982312006-10-02 02:18:22 -070095 shp->shm_perm.mode |= SHM_DEST;
96 /* Do not find it any more */
97 shp->shm_perm.key = IPC_PRIVATE;
98 shm_unlock(shp);
99 } else
100 shm_destroy(ns, shp);
101}
102
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800103#ifdef CONFIG_IPC_NS
Kirill Korotaev4e982312006-10-02 02:18:22 -0700104void shm_exit_ns(struct ipc_namespace *ns)
105{
Pierre Peiffer01b8b072008-02-08 04:18:57 -0800106 free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
Serge E. Hallyn7d6feeb2009-12-15 16:47:27 -0800107 idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700108}
Pavel Emelyanovae5e1b22008-02-08 04:18:22 -0800109#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110
Linus Torvalds140d0b22011-08-04 19:35:59 -1000111static int __init ipc_ns_init(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112{
Pierre Peiffered2ddbf2008-02-08 04:18:57 -0800113 shm_init_ns(&init_ipc_ns);
Linus Torvalds140d0b22011-08-04 19:35:59 -1000114 return 0;
115}
116
117pure_initcall(ipc_ns_init);
118
Manfred Spraul239521f2014-01-27 17:07:04 -0800119void __init shm_init(void)
Linus Torvalds140d0b22011-08-04 19:35:59 -1000120{
Mike Waychison19b49462005-09-06 15:17:10 -0700121 ipc_init_proc_interface("sysvipc/shm",
Helge Dellerb7952182010-10-27 15:34:16 -0700122#if BITS_PER_LONG <= 32
123 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
124#else
125 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
126#endif
Kirill Korotaev4e982312006-10-02 02:18:22 -0700127 IPC_SHM_IDS, sysvipc_shm_proc_show);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128}
129
Davidlohr Bueso8b8d52a2013-09-11 14:26:15 -0700130static inline struct shmid_kernel *shm_obtain_object(struct ipc_namespace *ns, int id)
131{
Davidlohr Bueso55b7ae52015-06-30 14:58:42 -0700132 struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(&shm_ids(ns), id);
Davidlohr Bueso8b8d52a2013-09-11 14:26:15 -0700133
134 if (IS_ERR(ipcp))
135 return ERR_CAST(ipcp);
136
137 return container_of(ipcp, struct shmid_kernel, shm_perm);
138}
139
140static inline struct shmid_kernel *shm_obtain_object_check(struct ipc_namespace *ns, int id)
141{
142 struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&shm_ids(ns), id);
143
144 if (IS_ERR(ipcp))
145 return ERR_CAST(ipcp);
146
147 return container_of(ipcp, struct shmid_kernel, shm_perm);
148}
149
Nadia Derbey3e148c72007-10-18 23:40:54 -0700150/*
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700151 * shm_lock_(check_) routines are called in the paths where the rwsem
Nadia Derbey00c2bf82008-07-25 01:48:03 -0700152 * is not necessarily held.
Nadia Derbey3e148c72007-10-18 23:40:54 -0700153 */
Nadia Derbey023a5352007-10-18 23:40:51 -0700154static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155{
Nadia Derbey03f02c72007-10-18 23:40:51 -0700156 struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
157
Davidlohr Buesoc5c89752015-06-30 14:58:36 -0700158 /*
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800159 * Callers of shm_lock() must validate the status of the returned ipc
160 * object pointer (as returned by ipc_lock()), and error out as
161 * appropriate.
Davidlohr Buesoc5c89752015-06-30 14:58:36 -0700162 */
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800163 if (IS_ERR(ipcp))
164 return (void *)ipcp;
Nadia Derbey03f02c72007-10-18 23:40:51 -0700165 return container_of(ipcp, struct shmid_kernel, shm_perm);
Nadia Derbey023a5352007-10-18 23:40:51 -0700166}
167
Vasiliy Kulikov4c677e22011-07-29 03:56:40 +0400168static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
169{
170 rcu_read_lock();
Davidlohr Buesocf9d5d72013-07-08 16:01:11 -0700171 ipc_lock_object(&ipcp->shm_perm);
Vasiliy Kulikov4c677e22011-07-29 03:56:40 +0400172}
173
Davidlohr Bueso53dad6d2013-09-23 17:04:45 -0700174static void shm_rcu_free(struct rcu_head *head)
175{
176 struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu);
177 struct shmid_kernel *shp = ipc_rcu_to_struct(p);
178
179 security_shm_free(shp);
180 ipc_rcu_free(head);
181}
182
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700183static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184{
Jack Millerab602f72014-08-08 14:23:19 -0700185 list_del(&s->shm_clist);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700186 ipc_rmid(&shm_ids(ns), &s->shm_perm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187}
188
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800190static int __shm_open(struct vm_area_struct *vma)
Kirill Korotaev4e982312006-10-02 02:18:22 -0700191{
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800192 struct file *file = vma->vm_file;
193 struct shm_file_data *sfd = shm_file_data(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 struct shmid_kernel *shp;
195
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800196 shp = shm_lock(sfd->ns, sfd->id);
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800197
198 if (IS_ERR(shp))
199 return PTR_ERR(shp);
200
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201 shp->shm_atim = get_seconds();
Pavel Emelyanovb4888932007-10-18 23:40:14 -0700202 shp->shm_lprid = task_tgid_vnr(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 shp->shm_nattch++;
204 shm_unlock(shp);
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800205 return 0;
206}
207
208/* This is called by fork, once for every shm attach. */
209static void shm_open(struct vm_area_struct *vma)
210{
211 int err = __shm_open(vma);
212 /*
213 * We raced in the idr lookup or with shm_destroy().
214 * Either way, the ID is busted.
215 */
216 WARN_ON_ONCE(err);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217}
218
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219/*
220 * shm_destroy - free the struct shmid_kernel
221 *
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700222 * @ns: namespace
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 * @shp: struct to free
224 *
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700225 * It has to be called with shp and shm_ids.rwsem (writer) locked,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226 * but returns with shp unlocked and freed.
227 */
Kirill Korotaev4e982312006-10-02 02:18:22 -0700228static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229{
Greg Thelena399b292013-11-21 14:32:00 -0800230 struct file *shm_file;
231
232 shm_file = shp->shm_file;
233 shp->shm_file = NULL;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700234 ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700235 shm_rmid(ns, shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 shm_unlock(shp);
Greg Thelena399b292013-11-21 14:32:00 -0800237 if (!is_file_hugepages(shm_file))
238 shmem_lock(shm_file, 0, shp->mlock_user);
Hugh Dickins353d5c32009-08-24 16:30:28 +0100239 else if (shp->mlock_user)
Dave Hansen07a46ed2014-12-12 16:58:22 -0800240 user_shm_unlock(i_size_read(file_inode(shm_file)),
241 shp->mlock_user);
Greg Thelena399b292013-11-21 14:32:00 -0800242 fput(shm_file);
Davidlohr Bueso53dad6d2013-09-23 17:04:45 -0700243 ipc_rcu_putref(shp, shm_rcu_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244}
245
246/*
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700247 * shm_may_destroy - identifies whether shm segment should be destroyed now
248 *
249 * Returns true if and only if there are no active users of the segment and
250 * one of the following is true:
251 *
252 * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
253 *
254 * 2) sysctl kernel.shm_rmid_forced is set to 1.
255 */
256static bool shm_may_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
257{
258 return (shp->shm_nattch == 0) &&
259 (ns->shm_rmid_forced ||
260 (shp->shm_perm.mode & SHM_DEST));
261}
262
263/*
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800264 * remove the attach descriptor vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265 * free memory for segment if it is marked destroyed.
266 * The descriptor has already been removed from the current->mm->mmap list
267 * and will later be kfree()d.
268 */
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800269static void shm_close(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270{
Manfred Spraul239521f2014-01-27 17:07:04 -0800271 struct file *file = vma->vm_file;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800272 struct shm_file_data *sfd = shm_file_data(file);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273 struct shmid_kernel *shp;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800274 struct ipc_namespace *ns = sfd->ns;
Kirill Korotaev4e982312006-10-02 02:18:22 -0700275
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700276 down_write(&shm_ids(ns).rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277 /* remove from the list of attaches of the shm segment */
Nadia Derbey00c2bf82008-07-25 01:48:03 -0700278 shp = shm_lock(ns, sfd->id);
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800279
280 /*
281 * We raced in the idr lookup or with shm_destroy().
282 * Either way, the ID is busted.
283 */
284 if (WARN_ON_ONCE(IS_ERR(shp)))
285 goto done; /* no-op */
286
Pavel Emelyanovb4888932007-10-18 23:40:14 -0700287 shp->shm_lprid = task_tgid_vnr(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288 shp->shm_dtim = get_seconds();
289 shp->shm_nattch--;
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700290 if (shm_may_destroy(ns, shp))
Kirill Korotaev4e982312006-10-02 02:18:22 -0700291 shm_destroy(ns, shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292 else
293 shm_unlock(shp);
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800294done:
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700295 up_write(&shm_ids(ns).rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296}
297
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700298/* Called with ns->shm_ids(ns).rwsem locked */
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700299static int shm_try_destroy_orphaned(int id, void *p, void *data)
300{
301 struct ipc_namespace *ns = data;
Vasiliy Kulikov4c677e22011-07-29 03:56:40 +0400302 struct kern_ipc_perm *ipcp = p;
303 struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700304
305 /*
306 * We want to destroy segments without users and with already
307 * exit'ed originating process.
Vasiliy Kulikov4c677e22011-07-29 03:56:40 +0400308 *
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700309 * As shp->* are changed under rwsem, it's safe to skip shp locking.
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700310 */
Vasiliy Kulikov4c677e22011-07-29 03:56:40 +0400311 if (shp->shm_creator != NULL)
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700312 return 0;
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700313
Vasiliy Kulikov4c677e22011-07-29 03:56:40 +0400314 if (shm_may_destroy(ns, shp)) {
315 shm_lock_by_ptr(shp);
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700316 shm_destroy(ns, shp);
Vasiliy Kulikov4c677e22011-07-29 03:56:40 +0400317 }
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700318 return 0;
319}
320
321void shm_destroy_orphaned(struct ipc_namespace *ns)
322{
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700323 down_write(&shm_ids(ns).rwsem);
Vasiliy Kulikov33a30ed2011-08-03 22:26:55 +0400324 if (shm_ids(ns).in_use)
Vasiliy Kulikov4c677e22011-07-29 03:56:40 +0400325 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700326 up_write(&shm_ids(ns).rwsem);
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700327}
328
Jack Miller83293c02014-08-08 14:23:21 -0700329/* Locking assumes this will only be called with task == current */
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700330void exit_shm(struct task_struct *task)
331{
Vasiliy Kulikov4c677e22011-07-29 03:56:40 +0400332 struct ipc_namespace *ns = task->nsproxy->ipc_ns;
Jack Millerab602f72014-08-08 14:23:19 -0700333 struct shmid_kernel *shp, *n;
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700334
Jack Miller83293c02014-08-08 14:23:21 -0700335 if (list_empty(&task->sysvshm.shm_clist))
Vasiliy Kulikov298507d2011-08-03 22:28:26 +0400336 return;
337
Jack Miller83293c02014-08-08 14:23:21 -0700338 /*
339 * If kernel.shm_rmid_forced is not set then only keep track of
340 * which shmids are orphaned, so that a later set of the sysctl
341 * can clean them up.
342 */
343 if (!ns->shm_rmid_forced) {
344 down_read(&shm_ids(ns).rwsem);
345 list_for_each_entry(shp, &task->sysvshm.shm_clist, shm_clist)
346 shp->shm_creator = NULL;
347 /*
348 * Only under read lock but we are only called on current
349 * so no entry on the list will be shared.
350 */
351 list_del(&task->sysvshm.shm_clist);
352 up_read(&shm_ids(ns).rwsem);
353 return;
354 }
355
356 /*
357 * Destroy all already created segments, that were not yet mapped,
358 * and mark any mapped as orphan to cover the sysctl toggling.
359 * Destroy is skipped if shm_may_destroy() returns false.
360 */
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700361 down_write(&shm_ids(ns).rwsem);
Jack Miller83293c02014-08-08 14:23:21 -0700362 list_for_each_entry_safe(shp, n, &task->sysvshm.shm_clist, shm_clist) {
363 shp->shm_creator = NULL;
364
365 if (shm_may_destroy(ns, shp)) {
366 shm_lock_by_ptr(shp);
367 shm_destroy(ns, shp);
368 }
369 }
370
371 /* Remove the list head from any segments still attached. */
Jack Millerab602f72014-08-08 14:23:19 -0700372 list_del(&task->sysvshm.shm_clist);
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700373 up_write(&shm_ids(ns).rwsem);
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -0700374}
375
Nick Piggind0217ac2007-07-19 01:47:03 -0700376static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800377{
378 struct file *file = vma->vm_file;
379 struct shm_file_data *sfd = shm_file_data(file);
380
Nick Piggind0217ac2007-07-19 01:47:03 -0700381 return sfd->vm_ops->fault(vma, vmf);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800382}
383
384#ifdef CONFIG_NUMA
Adrian Bunkd823e3e2007-10-16 23:26:42 -0700385static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800386{
387 struct file *file = vma->vm_file;
388 struct shm_file_data *sfd = shm_file_data(file);
389 int err = 0;
390 if (sfd->vm_ops->set_policy)
391 err = sfd->vm_ops->set_policy(vma, new);
392 return err;
393}
394
Adrian Bunkd823e3e2007-10-16 23:26:42 -0700395static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
396 unsigned long addr)
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800397{
398 struct file *file = vma->vm_file;
399 struct shm_file_data *sfd = shm_file_data(file);
400 struct mempolicy *pol = NULL;
401
402 if (sfd->vm_ops->get_policy)
403 pol = sfd->vm_ops->get_policy(vma, addr);
Lee Schermerhorn52cd3b02008-04-28 02:13:16 -0700404 else if (vma->vm_policy)
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800405 pol = vma->vm_policy;
Lee Schermerhorn52cd3b02008-04-28 02:13:16 -0700406
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800407 return pol;
408}
409#endif
410
Manfred Spraul239521f2014-01-27 17:07:04 -0800411static int shm_mmap(struct file *file, struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412{
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800413 struct shm_file_data *sfd = shm_file_data(file);
David Howellsb0e15192006-01-06 00:11:42 -0800414 int ret;
415
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800416 /*
417 * In case of remap_file_pages() emulation, the file can represent
418 * removed IPC ID: propogate shm_lock() error to caller.
419 */
420 ret =__shm_open(vma);
421 if (ret)
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800422 return ret;
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800423
424 ret = sfd->file->f_op->mmap(sfd->file, vma);
425 if (ret) {
426 shm_close(vma);
427 return ret;
428 }
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800429 sfd->vm_ops = vma->vm_ops;
David Howells2e92a3b2007-07-31 00:37:24 -0700430#ifdef CONFIG_MMU
Davidlohr Buesod0edd852015-09-09 15:39:20 -0700431 WARN_ON(!sfd->vm_ops->fault);
David Howells2e92a3b2007-07-31 00:37:24 -0700432#endif
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800433 vma->vm_ops = &shm_vm_ops;
Kirill A. Shutemov1ac0b6d2016-02-17 13:11:35 -0800434 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435}
436
Kirill Korotaev4e982312006-10-02 02:18:22 -0700437static int shm_release(struct inode *ino, struct file *file)
438{
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800439 struct shm_file_data *sfd = shm_file_data(file);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700440
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800441 put_ipc_ns(sfd->ns);
442 shm_file_data(file) = NULL;
443 kfree(sfd);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700444 return 0;
445}
446
Josef Bacik02c24a82011-07-16 20:44:56 -0400447static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
Adam Litke516dffd2007-03-01 15:46:08 -0800448{
Adam Litke516dffd2007-03-01 15:46:08 -0800449 struct shm_file_data *sfd = shm_file_data(file);
Adam Litke516dffd2007-03-01 15:46:08 -0800450
Christoph Hellwig7ea80852010-05-26 17:53:25 +0200451 if (!sfd->file->f_op->fsync)
452 return -EINVAL;
Josef Bacik02c24a82011-07-16 20:44:56 -0400453 return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
Adam Litke516dffd2007-03-01 15:46:08 -0800454}
455
Will Deacon7d8a4562012-06-07 14:21:13 -0700456static long shm_fallocate(struct file *file, int mode, loff_t offset,
457 loff_t len)
458{
459 struct shm_file_data *sfd = shm_file_data(file);
460
461 if (!sfd->file->f_op->fallocate)
462 return -EOPNOTSUPP;
463 return sfd->file->f_op->fallocate(file, mode, offset, len);
464}
465
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800466static unsigned long shm_get_unmapped_area(struct file *file,
467 unsigned long addr, unsigned long len, unsigned long pgoff,
468 unsigned long flags)
469{
470 struct shm_file_data *sfd = shm_file_data(file);
Al Viroc4caa772009-11-30 08:38:43 -0500471 return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
472 pgoff, flags);
Adam Litke516dffd2007-03-01 15:46:08 -0800473}
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800474
Arjan van de Ven9a321442007-02-12 00:55:35 -0800475static const struct file_operations shm_file_operations = {
Kirill Korotaev4e982312006-10-02 02:18:22 -0700476 .mmap = shm_mmap,
Adam Litke516dffd2007-03-01 15:46:08 -0800477 .fsync = shm_fsync,
Kirill Korotaev4e982312006-10-02 02:18:22 -0700478 .release = shm_release,
David Howellsed5e5892010-01-15 17:01:32 -0800479 .get_unmapped_area = shm_get_unmapped_area,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200480 .llseek = noop_llseek,
Will Deacon7d8a4562012-06-07 14:21:13 -0700481 .fallocate = shm_fallocate,
Al Viroc4caa772009-11-30 08:38:43 -0500482};
483
Hugh Dickinsc01d5b32016-07-26 15:26:15 -0700484/*
485 * shm_file_operations_huge is now identical to shm_file_operations,
486 * but we keep it distinct for the sake of is_file_shm_hugepages().
487 */
Al Viroc4caa772009-11-30 08:38:43 -0500488static const struct file_operations shm_file_operations_huge = {
489 .mmap = shm_mmap,
490 .fsync = shm_fsync,
491 .release = shm_release,
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800492 .get_unmapped_area = shm_get_unmapped_area,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200493 .llseek = noop_llseek,
Will Deacon7d8a4562012-06-07 14:21:13 -0700494 .fallocate = shm_fallocate,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495};
496
Yaowei Bai2954e4402016-01-20 15:01:11 -0800497bool is_file_shm_hugepages(struct file *file)
Al Viroc4caa772009-11-30 08:38:43 -0500498{
499 return file->f_op == &shm_file_operations_huge;
500}
501
Alexey Dobriyanf0f37e22009-09-27 22:29:37 +0400502static const struct vm_operations_struct shm_vm_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503 .open = shm_open, /* callback for a new vm-area open */
504 .close = shm_close, /* callback for when the vm-area is released */
Nick Piggin54cb8822007-07-19 01:46:59 -0700505 .fault = shm_fault,
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800506#if defined(CONFIG_NUMA)
507 .set_policy = shm_set_policy,
508 .get_policy = shm_get_policy,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509#endif
510};
511
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700512/**
513 * newseg - Create a new shared memory segment
514 * @ns: namespace
515 * @params: ptr to the structure that contains key, size and shmflg
516 *
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700517 * Called with shm_ids.rwsem held as a writer.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700518 */
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700519static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520{
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700521 key_t key = params->key;
522 int shmflg = params->flg;
523 size_t size = params->u.size;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524 int error;
525 struct shmid_kernel *shp;
Robin Holtd69f3ba2013-04-30 19:15:54 -0700526 size_t numpages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
Manfred Spraul239521f2014-01-27 17:07:04 -0800527 struct file *file;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528 char name[13];
529 int id;
KOSAKI Motohiroca16d142011-05-26 19:16:19 +0900530 vm_flags_t acctflag = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531
Kirill Korotaev4e982312006-10-02 02:18:22 -0700532 if (size < SHMMIN || size > ns->shm_ctlmax)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533 return -EINVAL;
534
Manfred Spraul13763272014-06-06 14:37:41 -0700535 if (numpages << PAGE_SHIFT < size)
536 return -ENOSPC;
537
Manfred Spraul09c6eb12014-06-06 14:37:40 -0700538 if (ns->shm_tot + numpages < ns->shm_tot ||
539 ns->shm_tot + numpages > ns->shm_ctlall)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540 return -ENOSPC;
541
542 shp = ipc_rcu_alloc(sizeof(*shp));
543 if (!shp)
544 return -ENOMEM;
545
546 shp->shm_perm.key = key;
Andrew Mortonb33291c2006-01-08 01:02:21 -0800547 shp->shm_perm.mode = (shmflg & S_IRWXUGO);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548 shp->mlock_user = NULL;
549
550 shp->shm_perm.security = NULL;
551 error = security_shm_alloc(shp);
552 if (error) {
Davidlohr Bueso53dad6d2013-09-23 17:04:45 -0700553 ipc_rcu_putref(shp, ipc_rcu_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554 return error;
555 }
556
Manfred Spraul239521f2014-01-27 17:07:04 -0800557 sprintf(name, "SYSV%08x", key);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700558 if (shmflg & SHM_HUGETLB) {
Andrew Mortonc103a4d2013-07-08 16:01:08 -0700559 struct hstate *hs;
Li Zefan091d0d52013-05-09 15:08:15 +0800560 size_t hugesize;
561
Andrew Mortonc103a4d2013-07-08 16:01:08 -0700562 hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
Li Zefan091d0d52013-05-09 15:08:15 +0800563 if (!hs) {
564 error = -EINVAL;
565 goto no_file;
566 }
567 hugesize = ALIGN(size, huge_page_size(hs));
Naoya Horiguchiaf73e4d2013-05-07 16:18:13 -0700568
Mel Gorman5a6fe122009-02-10 14:02:27 +0000569 /* hugetlb_file_setup applies strict accounting */
570 if (shmflg & SHM_NORESERVE)
571 acctflag = VM_NORESERVE;
Naoya Horiguchiaf73e4d2013-05-07 16:18:13 -0700572 file = hugetlb_file_setup(name, hugesize, acctflag,
Andi Kleen42d73952012-12-11 16:01:34 -0800573 &shp->mlock_user, HUGETLB_SHMFS_INODE,
574 (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700575 } else {
Badari Pulavartybf8f9722005-11-07 00:59:27 -0800576 /*
577 * Do not allow no accounting for OVERCOMMIT_NEVER, even
Manfred Spraul239521f2014-01-27 17:07:04 -0800578 * if it's asked for.
Badari Pulavartybf8f9722005-11-07 00:59:27 -0800579 */
580 if ((shmflg & SHM_NORESERVE) &&
581 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
Linus Torvaldsfc8744a2009-01-31 15:08:56 -0800582 acctflag = VM_NORESERVE;
Stephen Smalleye1832f22015-08-06 15:46:55 -0700583 file = shmem_kernel_file_setup(name, size, acctflag);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584 }
585 error = PTR_ERR(file);
586 if (IS_ERR(file))
587 goto no_file;
588
Pavel Emelyanovb4888932007-10-18 23:40:14 -0700589 shp->shm_cprid = task_tgid_vnr(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590 shp->shm_lprid = 0;
591 shp->shm_atim = shp->shm_dtim = 0;
592 shp->shm_ctim = get_seconds();
593 shp->shm_segsz = size;
594 shp->shm_nattch = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595 shp->shm_file = file;
Vasiliy Kulikov5774ed02011-07-29 03:55:31 +0400596 shp->shm_creator = current;
Linus Torvaldsb9a53222015-09-30 12:48:40 -0400597
598 id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
599 if (id < 0) {
600 error = id;
601 goto no_id;
602 }
603
Jack Millerab602f72014-08-08 14:23:19 -0700604 list_add(&shp->shm_clist, &current->sysvshm.shm_clist);
Davidlohr Buesodbfcd912013-07-08 16:01:09 -0700605
Badari Pulavarty30475cc2007-06-16 10:15:59 -0700606 /*
607 * shmid gets reported as "inode#" in /proc/pid/maps.
608 * proc-ps tools use this. Changing this will break them.
609 */
Al Viro496ad9a2013-01-23 17:07:38 -0500610 file_inode(file)->i_ino = shp->shm_perm.id;
Krishnakumar R551110a2005-10-29 18:16:45 -0700611
Kirill Korotaev4e982312006-10-02 02:18:22 -0700612 ns->shm_tot += numpages;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700613 error = shp->shm_perm.id;
Davidlohr Buesodbfcd912013-07-08 16:01:09 -0700614
Davidlohr Buesocf9d5d72013-07-08 16:01:11 -0700615 ipc_unlock_object(&shp->shm_perm);
Davidlohr Buesodbfcd912013-07-08 16:01:09 -0700616 rcu_read_unlock();
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700617 return error;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618
619no_id:
Hugh Dickins2195d282009-09-12 12:21:27 +0100620 if (is_file_hugepages(file) && shp->mlock_user)
Hugh Dickins353d5c32009-08-24 16:30:28 +0100621 user_shm_unlock(size, shp->mlock_user);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622 fput(file);
623no_file:
Davidlohr Bueso53dad6d2013-09-23 17:04:45 -0700624 ipc_rcu_putref(shp, shm_rcu_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700625 return error;
626}
627
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700628/*
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700629 * Called with shm_ids.rwsem and ipcp locked.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700630 */
Nadia Derbey03f02c72007-10-18 23:40:51 -0700631static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700632{
Nadia Derbey03f02c72007-10-18 23:40:51 -0700633 struct shmid_kernel *shp;
634
635 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
636 return security_shm_associate(shp, shmflg);
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700637}
638
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700639/*
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700640 * Called with shm_ids.rwsem and ipcp locked.
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700641 */
Nadia Derbey03f02c72007-10-18 23:40:51 -0700642static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
643 struct ipc_params *params)
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700644{
Nadia Derbey03f02c72007-10-18 23:40:51 -0700645 struct shmid_kernel *shp;
646
647 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
648 if (shp->shm_segsz < params->u.size)
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700649 return -EINVAL;
650
651 return 0;
652}
653
Heiko Carstensd5460c92009-01-14 14:14:27 +0100654SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655{
Kirill Korotaev4e982312006-10-02 02:18:22 -0700656 struct ipc_namespace *ns;
Mathias Krauseeb66ec42014-06-06 14:37:36 -0700657 static const struct ipc_ops shm_ops = {
658 .getnew = newseg,
659 .associate = shm_security,
660 .more_checks = shm_more_checks,
661 };
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700662 struct ipc_params shm_params;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700663
Kirill Korotaev4e982312006-10-02 02:18:22 -0700664 ns = current->nsproxy->ipc_ns;
665
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700666 shm_params.key = key;
667 shm_params.flg = shmflg;
668 shm_params.u.size = size;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700669
Nadia Derbey7748dbf2007-10-18 23:40:49 -0700670 return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671}
672
673static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
674{
Manfred Spraul239521f2014-01-27 17:07:04 -0800675 switch (version) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676 case IPC_64:
677 return copy_to_user(buf, in, sizeof(*in));
678 case IPC_OLD:
679 {
680 struct shmid_ds out;
681
Vasiliy Kulikov3af54c92010-10-30 18:22:49 +0400682 memset(&out, 0, sizeof(out));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700683 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
684 out.shm_segsz = in->shm_segsz;
685 out.shm_atime = in->shm_atime;
686 out.shm_dtime = in->shm_dtime;
687 out.shm_ctime = in->shm_ctime;
688 out.shm_cpid = in->shm_cpid;
689 out.shm_lpid = in->shm_lpid;
690 out.shm_nattch = in->shm_nattch;
691
692 return copy_to_user(buf, &out, sizeof(out));
693 }
694 default:
695 return -EINVAL;
696 }
697}
698
Pierre Peiffer016d7132008-04-29 01:00:50 -0700699static inline unsigned long
700copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701{
Manfred Spraul239521f2014-01-27 17:07:04 -0800702 switch (version) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703 case IPC_64:
Pierre Peiffer016d7132008-04-29 01:00:50 -0700704 if (copy_from_user(out, buf, sizeof(*out)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705 return -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700706 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707 case IPC_OLD:
708 {
709 struct shmid_ds tbuf_old;
710
711 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
712 return -EFAULT;
713
Pierre Peiffer016d7132008-04-29 01:00:50 -0700714 out->shm_perm.uid = tbuf_old.shm_perm.uid;
715 out->shm_perm.gid = tbuf_old.shm_perm.gid;
716 out->shm_perm.mode = tbuf_old.shm_perm.mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700717
718 return 0;
719 }
720 default:
721 return -EINVAL;
722 }
723}
724
725static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
726{
Manfred Spraul239521f2014-01-27 17:07:04 -0800727 switch (version) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728 case IPC_64:
729 return copy_to_user(buf, in, sizeof(*in));
730 case IPC_OLD:
731 {
732 struct shminfo out;
733
Manfred Spraul239521f2014-01-27 17:07:04 -0800734 if (in->shmmax > INT_MAX)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 out.shmmax = INT_MAX;
736 else
737 out.shmmax = (int)in->shmmax;
738
739 out.shmmin = in->shmmin;
740 out.shmmni = in->shmmni;
741 out.shmseg = in->shmseg;
Paul McQuade46c0a8c2014-06-06 14:37:37 -0700742 out.shmall = in->shmall;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743
744 return copy_to_user(buf, &out, sizeof(out));
745 }
746 default:
747 return -EINVAL;
748 }
749}
750
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700751/*
Helge Dellerb7952182010-10-27 15:34:16 -0700752 * Calculate and add used RSS and swap pages of a shm.
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700753 * Called with shm_ids.rwsem held as a reader
Helge Dellerb7952182010-10-27 15:34:16 -0700754 */
755static void shm_add_rss_swap(struct shmid_kernel *shp,
756 unsigned long *rss_add, unsigned long *swp_add)
757{
758 struct inode *inode;
759
Al Viro496ad9a2013-01-23 17:07:38 -0500760 inode = file_inode(shp->shm_file);
Helge Dellerb7952182010-10-27 15:34:16 -0700761
762 if (is_file_hugepages(shp->shm_file)) {
763 struct address_space *mapping = inode->i_mapping;
764 struct hstate *h = hstate_file(shp->shm_file);
765 *rss_add += pages_per_huge_page(h) * mapping->nrpages;
766 } else {
767#ifdef CONFIG_SHMEM
768 struct shmem_inode_info *info = SHMEM_I(inode);
Kirill A. Shutemov4595ef82016-07-26 15:26:29 -0700769 spin_lock_irq(&info->lock);
Helge Dellerb7952182010-10-27 15:34:16 -0700770 *rss_add += inode->i_mapping->nrpages;
771 *swp_add += info->swapped;
Kirill A. Shutemov4595ef82016-07-26 15:26:29 -0700772 spin_unlock_irq(&info->lock);
Helge Dellerb7952182010-10-27 15:34:16 -0700773#else
774 *rss_add += inode->i_mapping->nrpages;
775#endif
776 }
777}
778
779/*
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700780 * Called with shm_ids.rwsem held as a reader
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700781 */
Kirill Korotaev4e982312006-10-02 02:18:22 -0700782static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
783 unsigned long *swp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700784{
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700785 int next_id;
786 int total, in_use;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700787
788 *rss = 0;
789 *swp = 0;
790
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700791 in_use = shm_ids(ns).in_use;
792
793 for (total = 0, next_id = 0; total < in_use; next_id++) {
Tony Battersbye562aeb2009-04-02 16:58:26 -0700794 struct kern_ipc_perm *ipc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700795 struct shmid_kernel *shp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700796
Tony Battersbye562aeb2009-04-02 16:58:26 -0700797 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
798 if (ipc == NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700799 continue;
Tony Battersbye562aeb2009-04-02 16:58:26 -0700800 shp = container_of(ipc, struct shmid_kernel, shm_perm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801
Helge Dellerb7952182010-10-27 15:34:16 -0700802 shm_add_rss_swap(shp, rss, swp);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700803
804 total++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700805 }
806}
807
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700808/*
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700809 * This function handles some shmctl commands which require the rwsem
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700810 * to be held in write mode.
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700811 * NOTE: no locks must be held, the rwsem is taken inside this function.
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700812 */
813static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
814 struct shmid_ds __user *buf, int version)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815{
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700816 struct kern_ipc_perm *ipcp;
Pierre Peiffer016d7132008-04-29 01:00:50 -0700817 struct shmid64_ds shmid64;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700818 struct shmid_kernel *shp;
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700819 int err;
820
821 if (cmd == IPC_SET) {
Pierre Peiffer016d7132008-04-29 01:00:50 -0700822 if (copy_shmid_from_user(&shmid64, buf, version))
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700823 return -EFAULT;
824 }
825
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700826 down_write(&shm_ids(ns).rwsem);
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -0700827 rcu_read_lock();
828
Davidlohr Bueso79ccf0f2013-09-11 14:26:16 -0700829 ipcp = ipcctl_pre_down_nolock(ns, &shm_ids(ns), shmid, cmd,
830 &shmid64.shm_perm, 0);
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -0700831 if (IS_ERR(ipcp)) {
832 err = PTR_ERR(ipcp);
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -0700833 goto out_unlock1;
834 }
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700835
Pierre Peiffera5f75e72008-04-29 01:00:54 -0700836 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700837
838 err = security_shm_shmctl(shp, cmd);
839 if (err)
Davidlohr Bueso79ccf0f2013-09-11 14:26:16 -0700840 goto out_unlock1;
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -0700841
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700842 switch (cmd) {
843 case IPC_RMID:
Davidlohr Bueso79ccf0f2013-09-11 14:26:16 -0700844 ipc_lock_object(&shp->shm_perm);
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -0700845 /* do_shm_rmid unlocks the ipc object and rcu */
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700846 do_shm_rmid(ns, ipcp);
847 goto out_up;
848 case IPC_SET:
Davidlohr Bueso79ccf0f2013-09-11 14:26:16 -0700849 ipc_lock_object(&shp->shm_perm);
Eric W. Biederman1efdb692012-02-07 16:54:11 -0800850 err = ipc_update_perm(&shmid64.shm_perm, ipcp);
851 if (err)
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -0700852 goto out_unlock0;
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700853 shp->shm_ctim = get_seconds();
854 break;
855 default:
856 err = -EINVAL;
Davidlohr Bueso79ccf0f2013-09-11 14:26:16 -0700857 goto out_unlock1;
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700858 }
Davidlohr Bueso7b4cc5d2013-07-08 16:01:12 -0700859
860out_unlock0:
861 ipc_unlock_object(&shp->shm_perm);
862out_unlock1:
863 rcu_read_unlock();
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700864out_up:
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700865 up_write(&shm_ids(ns).rwsem);
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700866 return err;
867}
868
Davidlohr Bueso68eccc12013-09-11 14:26:18 -0700869static int shmctl_nolock(struct ipc_namespace *ns, int shmid,
870 int cmd, int version, void __user *buf)
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700871{
Davidlohr Bueso68eccc12013-09-11 14:26:18 -0700872 int err;
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -0700873 struct shmid_kernel *shp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700874
Davidlohr Bueso68eccc12013-09-11 14:26:18 -0700875 /* preliminary security checks for *_INFO */
876 if (cmd == IPC_INFO || cmd == SHM_INFO) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700877 err = security_shm_shmctl(NULL, cmd);
878 if (err)
879 return err;
Davidlohr Bueso68eccc12013-09-11 14:26:18 -0700880 }
881
882 switch (cmd) {
883 case IPC_INFO:
884 {
885 struct shminfo64 shminfo;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700886
WANG Conge8148f72009-01-06 14:42:49 -0800887 memset(&shminfo, 0, sizeof(shminfo));
Kirill Korotaev4e982312006-10-02 02:18:22 -0700888 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
889 shminfo.shmmax = ns->shm_ctlmax;
890 shminfo.shmall = ns->shm_ctlall;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700891
892 shminfo.shmmin = SHMMIN;
Manfred Spraul239521f2014-01-27 17:07:04 -0800893 if (copy_shminfo_to_user(buf, &shminfo, version))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700894 return -EFAULT;
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700895
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700896 down_read(&shm_ids(ns).rwsem);
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700897 err = ipc_get_maxid(&shm_ids(ns));
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700898 up_read(&shm_ids(ns).rwsem);
Nadia Derbeyf4566f02007-10-18 23:40:53 -0700899
Manfred Spraul239521f2014-01-27 17:07:04 -0800900 if (err < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700901 err = 0;
902 goto out;
903 }
904 case SHM_INFO:
905 {
906 struct shm_info shm_info;
907
WANG Conge8148f72009-01-06 14:42:49 -0800908 memset(&shm_info, 0, sizeof(shm_info));
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700909 down_read(&shm_ids(ns).rwsem);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700910 shm_info.used_ids = shm_ids(ns).in_use;
Manfred Spraul239521f2014-01-27 17:07:04 -0800911 shm_get_stat(ns, &shm_info.shm_rss, &shm_info.shm_swp);
Kirill Korotaev4e982312006-10-02 02:18:22 -0700912 shm_info.shm_tot = ns->shm_tot;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700913 shm_info.swap_attempts = 0;
914 shm_info.swap_successes = 0;
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700915 err = ipc_get_maxid(&shm_ids(ns));
Davidlohr Buesod9a605e2013-09-11 14:26:24 -0700916 up_read(&shm_ids(ns).rwsem);
WANG Conge8148f72009-01-06 14:42:49 -0800917 if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700918 err = -EFAULT;
919 goto out;
920 }
921
922 err = err < 0 ? 0 : err;
923 goto out;
924 }
925 case SHM_STAT:
926 case IPC_STAT:
927 {
928 struct shmid64_ds tbuf;
929 int result;
Nadia Derbey023a5352007-10-18 23:40:51 -0700930
Davidlohr Buesoc97cb9c2013-09-11 14:26:20 -0700931 rcu_read_lock();
Nadia Derbey023a5352007-10-18 23:40:51 -0700932 if (cmd == SHM_STAT) {
Davidlohr Buesoc97cb9c2013-09-11 14:26:20 -0700933 shp = shm_obtain_object(ns, shmid);
Nadia Derbey023a5352007-10-18 23:40:51 -0700934 if (IS_ERR(shp)) {
935 err = PTR_ERR(shp);
Davidlohr Buesoc97cb9c2013-09-11 14:26:20 -0700936 goto out_unlock;
Nadia Derbey023a5352007-10-18 23:40:51 -0700937 }
Nadia Derbey7ca7e562007-10-18 23:40:48 -0700938 result = shp->shm_perm.id;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700939 } else {
Davidlohr Buesoc97cb9c2013-09-11 14:26:20 -0700940 shp = shm_obtain_object_check(ns, shmid);
Nadia Derbey023a5352007-10-18 23:40:51 -0700941 if (IS_ERR(shp)) {
942 err = PTR_ERR(shp);
Davidlohr Buesoc97cb9c2013-09-11 14:26:20 -0700943 goto out_unlock;
Nadia Derbey023a5352007-10-18 23:40:51 -0700944 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700945 result = 0;
946 }
Davidlohr Buesoc97cb9c2013-09-11 14:26:20 -0700947
WANG Conge8148f72009-01-06 14:42:49 -0800948 err = -EACCES;
Serge E. Hallynb0e77592011-03-23 16:43:24 -0700949 if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700950 goto out_unlock;
Davidlohr Buesoc97cb9c2013-09-11 14:26:20 -0700951
Linus Torvalds1da177e2005-04-16 15:20:36 -0700952 err = security_shm_shmctl(shp, cmd);
953 if (err)
954 goto out_unlock;
Davidlohr Buesoc97cb9c2013-09-11 14:26:20 -0700955
Nadia Derbey023a5352007-10-18 23:40:51 -0700956 memset(&tbuf, 0, sizeof(tbuf));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700957 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
958 tbuf.shm_segsz = shp->shm_segsz;
959 tbuf.shm_atime = shp->shm_atim;
960 tbuf.shm_dtime = shp->shm_dtim;
961 tbuf.shm_ctime = shp->shm_ctim;
962 tbuf.shm_cpid = shp->shm_cprid;
963 tbuf.shm_lpid = shp->shm_lprid;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -0800964 tbuf.shm_nattch = shp->shm_nattch;
Davidlohr Buesoc97cb9c2013-09-11 14:26:20 -0700965 rcu_read_unlock();
966
967 if (copy_shmid_to_user(buf, &tbuf, version))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700968 err = -EFAULT;
969 else
970 err = result;
971 goto out;
972 }
Davidlohr Bueso68eccc12013-09-11 14:26:18 -0700973 default:
974 return -EINVAL;
975 }
976
977out_unlock:
Davidlohr Buesoc97cb9c2013-09-11 14:26:20 -0700978 rcu_read_unlock();
Davidlohr Bueso68eccc12013-09-11 14:26:18 -0700979out:
980 return err;
981}
982
983SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
984{
985 struct shmid_kernel *shp;
986 int err, version;
987 struct ipc_namespace *ns;
988
Davidlohr Bueso2caacaa2013-09-11 14:26:21 -0700989 if (cmd < 0 || shmid < 0)
990 return -EINVAL;
Davidlohr Bueso68eccc12013-09-11 14:26:18 -0700991
992 version = ipc_parse_version(&cmd);
993 ns = current->nsproxy->ipc_ns;
994
995 switch (cmd) {
996 case IPC_INFO:
997 case SHM_INFO:
998 case SHM_STAT:
999 case IPC_STAT:
1000 return shmctl_nolock(ns, shmid, cmd, version, buf);
Davidlohr Bueso2caacaa2013-09-11 14:26:21 -07001001 case IPC_RMID:
1002 case IPC_SET:
1003 return shmctl_down(ns, shmid, cmd, buf, version);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001004 case SHM_LOCK:
1005 case SHM_UNLOCK:
1006 {
Hugh Dickins850465792012-01-20 14:34:19 -08001007 struct file *shm_file;
Lee Schermerhorn89e004ea2008-10-18 20:26:43 -07001008
Davidlohr Bueso2caacaa2013-09-11 14:26:21 -07001009 rcu_read_lock();
1010 shp = shm_obtain_object_check(ns, shmid);
Nadia Derbey023a5352007-10-18 23:40:51 -07001011 if (IS_ERR(shp)) {
1012 err = PTR_ERR(shp);
Davidlohr Bueso2caacaa2013-09-11 14:26:21 -07001013 goto out_unlock1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001015
Al Viroa33e6752008-12-10 03:40:06 -05001016 audit_ipc_obj(&(shp->shm_perm));
Davidlohr Bueso2caacaa2013-09-11 14:26:21 -07001017 err = security_shm_shmctl(shp, cmd);
1018 if (err)
1019 goto out_unlock1;
Steve Grubb073115d2006-04-02 17:07:33 -04001020
Davidlohr Bueso2caacaa2013-09-11 14:26:21 -07001021 ipc_lock_object(&shp->shm_perm);
Rafael Aquini0f3d2b02014-01-27 17:07:01 -08001022
1023 /* check if shm_destroy() is tearing down shp */
1024 if (!ipc_valid_object(&shp->shm_perm)) {
1025 err = -EIDRM;
1026 goto out_unlock0;
1027 }
1028
Serge E. Hallynb0e77592011-03-23 16:43:24 -07001029 if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
Eric W. Biederman1efdb692012-02-07 16:54:11 -08001030 kuid_t euid = current_euid();
Eric W. Biederman1efdb692012-02-07 16:54:11 -08001031 if (!uid_eq(euid, shp->shm_perm.uid) &&
Jesper Nilsson3a726602013-11-21 14:32:08 -08001032 !uid_eq(euid, shp->shm_perm.cuid)) {
1033 err = -EPERM;
Davidlohr Bueso2caacaa2013-09-11 14:26:21 -07001034 goto out_unlock0;
Jesper Nilsson3a726602013-11-21 14:32:08 -08001035 }
1036 if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) {
1037 err = -EPERM;
Davidlohr Bueso2caacaa2013-09-11 14:26:21 -07001038 goto out_unlock0;
Jesper Nilsson3a726602013-11-21 14:32:08 -08001039 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001040 }
1041
Hugh Dickins850465792012-01-20 14:34:19 -08001042 shm_file = shp->shm_file;
1043 if (is_file_hugepages(shm_file))
Davidlohr Bueso2caacaa2013-09-11 14:26:21 -07001044 goto out_unlock0;
Hugh Dickins850465792012-01-20 14:34:19 -08001045
1046 if (cmd == SHM_LOCK) {
David Howells86a264a2008-11-14 10:39:18 +11001047 struct user_struct *user = current_user();
Hugh Dickins850465792012-01-20 14:34:19 -08001048 err = shmem_lock(shm_file, 1, user);
1049 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
1050 shp->shm_perm.mode |= SHM_LOCKED;
1051 shp->mlock_user = user;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001052 }
Davidlohr Bueso2caacaa2013-09-11 14:26:21 -07001053 goto out_unlock0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001054 }
Hugh Dickins850465792012-01-20 14:34:19 -08001055
1056 /* SHM_UNLOCK */
1057 if (!(shp->shm_perm.mode & SHM_LOCKED))
Davidlohr Bueso2caacaa2013-09-11 14:26:21 -07001058 goto out_unlock0;
Hugh Dickins850465792012-01-20 14:34:19 -08001059 shmem_lock(shm_file, 0, shp->mlock_user);
1060 shp->shm_perm.mode &= ~SHM_LOCKED;
1061 shp->mlock_user = NULL;
1062 get_file(shm_file);
Davidlohr Bueso2caacaa2013-09-11 14:26:21 -07001063 ipc_unlock_object(&shp->shm_perm);
1064 rcu_read_unlock();
Hugh Dickins24513262012-01-20 14:34:21 -08001065 shmem_unlock_mapping(shm_file->f_mapping);
Davidlohr Bueso2caacaa2013-09-11 14:26:21 -07001066
Hugh Dickins850465792012-01-20 14:34:19 -08001067 fput(shm_file);
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -07001068 return err;
Davidlohr Bueso2caacaa2013-09-11 14:26:21 -07001069 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001070 default:
Pierre Peiffer8d4cc8b2008-04-29 01:00:47 -07001071 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001072 }
1073
Davidlohr Bueso2caacaa2013-09-11 14:26:21 -07001074out_unlock0:
1075 ipc_unlock_object(&shp->shm_perm);
1076out_unlock1:
1077 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001078 return err;
1079}
1080
1081/*
1082 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
1083 *
1084 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
1085 * "raddr" thing points to kernel space, and there has to be a wrapper around
1086 * this.
1087 */
Davidlohr Bueso270e84a2017-02-27 14:28:24 -08001088long do_shmat(int shmid, char __user *shmaddr, int shmflg,
1089 ulong *raddr, unsigned long shmlba)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001090{
1091 struct shmid_kernel *shp;
1092 unsigned long addr;
1093 unsigned long size;
Manfred Spraul239521f2014-01-27 17:07:04 -08001094 struct file *file;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001095 int err;
1096 unsigned long flags;
1097 unsigned long prot;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001098 int acc_mode;
Kirill Korotaev4e982312006-10-02 02:18:22 -07001099 struct ipc_namespace *ns;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001100 struct shm_file_data *sfd;
1101 struct path path;
Al Viroaeb5d722008-09-02 15:28:45 -04001102 fmode_t f_mode;
Michel Lespinasse41badc12013-02-22 16:32:47 -08001103 unsigned long populate = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001104
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001105 err = -EINVAL;
1106 if (shmid < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001107 goto out;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001108 else if ((addr = (ulong)shmaddr)) {
Will Deacon079a96a2012-07-30 14:42:38 -07001109 if (addr & (shmlba - 1)) {
Davidlohr Bueso270e84a2017-02-27 14:28:24 -08001110 /*
1111 * Round down to the nearest multiple of shmlba.
1112 * For sane do_mmap_pgoff() parameters, avoid
1113 * round downs that trigger nil-page and MAP_FIXED.
1114 */
1115 if ((shmflg & SHM_RND) && addr >= shmlba)
1116 addr &= ~(shmlba - 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001117 else
1118#ifndef __ARCH_FORCE_SHMLBA
1119 if (addr & ~PAGE_MASK)
1120#endif
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001121 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001122 }
1123 flags = MAP_SHARED | MAP_FIXED;
1124 } else {
1125 if ((shmflg & SHM_REMAP))
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001126 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001127
1128 flags = MAP_SHARED;
1129 }
1130
1131 if (shmflg & SHM_RDONLY) {
1132 prot = PROT_READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001133 acc_mode = S_IRUGO;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001134 f_mode = FMODE_READ;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001135 } else {
1136 prot = PROT_READ | PROT_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001137 acc_mode = S_IRUGO | S_IWUGO;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001138 f_mode = FMODE_READ | FMODE_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001139 }
1140 if (shmflg & SHM_EXEC) {
1141 prot |= PROT_EXEC;
1142 acc_mode |= S_IXUGO;
1143 }
1144
1145 /*
1146 * We cannot rely on the fs check since SYSV IPC does have an
1147 * additional creator id...
1148 */
Kirill Korotaev4e982312006-10-02 02:18:22 -07001149 ns = current->nsproxy->ipc_ns;
Davidlohr Buesoc2c737a2013-09-11 14:26:23 -07001150 rcu_read_lock();
1151 shp = shm_obtain_object_check(ns, shmid);
Nadia Derbey023a5352007-10-18 23:40:51 -07001152 if (IS_ERR(shp)) {
1153 err = PTR_ERR(shp);
Davidlohr Buesoc2c737a2013-09-11 14:26:23 -07001154 goto out_unlock;
Nadia Derbey023a5352007-10-18 23:40:51 -07001155 }
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001156
1157 err = -EACCES;
Serge E. Hallynb0e77592011-03-23 16:43:24 -07001158 if (ipcperms(ns, &shp->shm_perm, acc_mode))
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001159 goto out_unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001160
1161 err = security_shm_shmat(shp, shmaddr, shmflg);
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001162 if (err)
1163 goto out_unlock;
1164
Davidlohr Buesoc2c737a2013-09-11 14:26:23 -07001165 ipc_lock_object(&shp->shm_perm);
Greg Thelena399b292013-11-21 14:32:00 -08001166
1167 /* check if shm_destroy() is tearing down shp */
Rafael Aquini0f3d2b02014-01-27 17:07:01 -08001168 if (!ipc_valid_object(&shp->shm_perm)) {
Greg Thelena399b292013-11-21 14:32:00 -08001169 ipc_unlock_object(&shp->shm_perm);
1170 err = -EIDRM;
1171 goto out_unlock;
1172 }
1173
Al Viro2c48b9c2009-08-09 00:52:35 +04001174 path = shp->shm_file->f_path;
1175 path_get(&path);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001176 shp->shm_nattch++;
David Howells75c3cfa2015-03-17 22:26:12 +00001177 size = i_size_read(d_inode(path.dentry));
Davidlohr Buesoc2c737a2013-09-11 14:26:23 -07001178 ipc_unlock_object(&shp->shm_perm);
1179 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001180
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001181 err = -ENOMEM;
1182 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
Davidlohr Buesof42569b2013-09-11 14:26:22 -07001183 if (!sfd) {
1184 path_put(&path);
1185 goto out_nattch;
1186 }
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001187
Al Viro2c48b9c2009-08-09 00:52:35 +04001188 file = alloc_file(&path, f_mode,
1189 is_file_hugepages(shp->shm_file) ?
Al Viroc4caa772009-11-30 08:38:43 -05001190 &shm_file_operations_huge :
1191 &shm_file_operations);
Anatol Pomozov39b65252012-09-12 20:11:55 -07001192 err = PTR_ERR(file);
Davidlohr Buesof42569b2013-09-11 14:26:22 -07001193 if (IS_ERR(file)) {
1194 kfree(sfd);
1195 path_put(&path);
1196 goto out_nattch;
1197 }
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001198
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001199 file->private_data = sfd;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001200 file->f_mapping = shp->shm_file->f_mapping;
Nadia Derbey7ca7e562007-10-18 23:40:48 -07001201 sfd->id = shp->shm_perm.id;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001202 sfd->ns = get_ipc_ns(ns);
1203 sfd->file = shp->shm_file;
1204 sfd->vm_ops = NULL;
1205
Al Viro8b3ec682012-05-30 17:11:23 -04001206 err = security_mmap_file(file, prot, flags);
1207 if (err)
1208 goto out_fput;
1209
Michal Hocko91f4f942016-05-23 16:25:51 -07001210 if (down_write_killable(&current->mm->mmap_sem)) {
1211 err = -EINTR;
1212 goto out_fput;
1213 }
1214
Linus Torvalds1da177e2005-04-16 15:20:36 -07001215 if (addr && !(shmflg & SHM_REMAP)) {
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001216 err = -EINVAL;
Manfred Spraul247a8ce2014-06-06 14:37:38 -07001217 if (addr + size < addr)
1218 goto invalid;
1219
Linus Torvalds1da177e2005-04-16 15:20:36 -07001220 if (find_vma_intersection(current->mm, addr, addr + size))
1221 goto invalid;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001222 }
Davidlohr Buesof42569b2013-09-11 14:26:22 -07001223
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001224 addr = do_mmap_pgoff(file, addr, size, prot, flags, 0, &populate);
1225 *raddr = addr;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001226 err = 0;
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001227 if (IS_ERR_VALUE(addr))
1228 err = (long)addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001229invalid:
1230 up_write(&current->mm->mmap_sem);
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001231 if (populate)
Michel Lespinasse41badc12013-02-22 16:32:47 -08001232 mm_populate(addr, populate);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001233
Al Viro8b3ec682012-05-30 17:11:23 -04001234out_fput:
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001235 fput(file);
1236
1237out_nattch:
Davidlohr Buesod9a605e2013-09-11 14:26:24 -07001238 down_write(&shm_ids(ns).rwsem);
Nadia Derbey00c2bf82008-07-25 01:48:03 -07001239 shp = shm_lock(ns, shmid);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001240 shp->shm_nattch--;
Vasiliy Kulikovb34a6b12011-07-26 16:08:48 -07001241 if (shm_may_destroy(ns, shp))
Kirill Korotaev4e982312006-10-02 02:18:22 -07001242 shm_destroy(ns, shp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001243 else
1244 shm_unlock(shp);
Davidlohr Buesod9a605e2013-09-11 14:26:24 -07001245 up_write(&shm_ids(ns).rwsem);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001246 return err;
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001247
1248out_unlock:
Davidlohr Buesoc2c737a2013-09-11 14:26:23 -07001249 rcu_read_unlock();
Davidlohr Buesof42569b2013-09-11 14:26:22 -07001250out:
1251 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001252}
1253
Heiko Carstensd5460c92009-01-14 14:14:27 +01001254SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
Stephen Rothwell7d87e14c2005-05-01 08:59:12 -07001255{
1256 unsigned long ret;
1257 long err;
1258
Will Deacon079a96a2012-07-30 14:42:38 -07001259 err = do_shmat(shmid, shmaddr, shmflg, &ret, SHMLBA);
Stephen Rothwell7d87e14c2005-05-01 08:59:12 -07001260 if (err)
1261 return err;
1262 force_successful_syscall_return();
1263 return (long)ret;
1264}
1265
Linus Torvalds1da177e2005-04-16 15:20:36 -07001266/*
1267 * detach and kill segment if marked destroyed.
1268 * The work is done in shm_close.
1269 */
Heiko Carstensd5460c92009-01-14 14:14:27 +01001270SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001271{
1272 struct mm_struct *mm = current->mm;
Mike Frysinger586c7e62009-06-09 16:26:23 -07001273 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001274 unsigned long addr = (unsigned long)shmaddr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001275 int retval = -EINVAL;
Mike Frysinger586c7e62009-06-09 16:26:23 -07001276#ifdef CONFIG_MMU
1277 loff_t size = 0;
Dave Hansend3c97902014-12-12 16:58:19 -08001278 struct file *file;
Mike Frysinger586c7e62009-06-09 16:26:23 -07001279 struct vm_area_struct *next;
1280#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07001281
Hugh Dickinsdf1e2fb2006-03-24 03:18:06 -08001282 if (addr & ~PAGE_MASK)
1283 return retval;
1284
Michal Hocko91f4f942016-05-23 16:25:51 -07001285 if (down_write_killable(&mm->mmap_sem))
1286 return -EINTR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001287
1288 /*
1289 * This function tries to be smart and unmap shm segments that
1290 * were modified by partial mlock or munmap calls:
1291 * - It first determines the size of the shm segment that should be
1292 * unmapped: It searches for a vma that is backed by shm and that
1293 * started at address shmaddr. It records it's size and then unmaps
1294 * it.
1295 * - Then it unmaps all shm vmas that started at shmaddr and that
Dave Hansend3c97902014-12-12 16:58:19 -08001296 * are within the initially determined size and that are from the
1297 * same shm segment from which we determined the size.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001298 * Errors from do_munmap are ignored: the function only fails if
1299 * it's called with invalid parameters or if it's called to unmap
1300 * a part of a vma. Both calls in this function are for full vmas,
1301 * the parameters are directly copied from the vma itself and always
1302 * valid - therefore do_munmap cannot fail. (famous last words?)
1303 */
1304 /*
1305 * If it had been mremap()'d, the starting address would not
1306 * match the usual checks anyway. So assume all vma's are
1307 * above the starting address given.
1308 */
1309 vma = find_vma(mm, addr);
1310
David Howells8feae132009-01-08 12:04:47 +00001311#ifdef CONFIG_MMU
Linus Torvalds1da177e2005-04-16 15:20:36 -07001312 while (vma) {
1313 next = vma->vm_next;
1314
1315 /*
1316 * Check if the starting address would match, i.e. it's
1317 * a fragment created by mprotect() and/or munmap(), or it
1318 * otherwise it starts at this address with no hassles.
1319 */
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001320 if ((vma->vm_ops == &shm_vm_ops) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -07001321 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1322
Dave Hansend3c97902014-12-12 16:58:19 -08001323 /*
1324 * Record the file of the shm segment being
1325 * unmapped. With mremap(), someone could place
1326 * page from another segment but with equal offsets
1327 * in the range we are unmapping.
1328 */
1329 file = vma->vm_file;
Dave Hansen07a46ed2014-12-12 16:58:22 -08001330 size = i_size_read(file_inode(vma->vm_file));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001331 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1332 /*
1333 * We discovered the size of the shm segment, so
1334 * break out of here and fall through to the next
1335 * loop that uses the size information to stop
1336 * searching for matching vma's.
1337 */
1338 retval = 0;
1339 vma = next;
1340 break;
1341 }
1342 vma = next;
1343 }
1344
1345 /*
1346 * We need look no further than the maximum address a fragment
1347 * could possibly have landed at. Also cast things to loff_t to
Lucas De Marchi25985ed2011-03-30 22:57:33 -03001348 * prevent overflows and make comparisons vs. equal-width types.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001349 */
KAMEZAWA Hiroyuki8e367092006-02-10 01:51:12 -08001350 size = PAGE_ALIGN(size);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001351 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1352 next = vma->vm_next;
1353
1354 /* finding a matching vma now does not alter retval */
Eric W. Biedermanbc56bba2007-02-20 13:57:53 -08001355 if ((vma->vm_ops == &shm_vm_ops) &&
Dave Hansend3c97902014-12-12 16:58:19 -08001356 ((vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) &&
1357 (vma->vm_file == file))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001358 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1359 vma = next;
1360 }
1361
David Howells8feae132009-01-08 12:04:47 +00001362#else /* CONFIG_MMU */
1363 /* under NOMMU conditions, the exact address to be destroyed must be
1364 * given */
Davidlohr Bueso530fcd162013-09-11 14:26:28 -07001365 if (vma && vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
David Howells8feae132009-01-08 12:04:47 +00001366 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1367 retval = 0;
1368 }
1369
1370#endif
1371
Linus Torvalds1da177e2005-04-16 15:20:36 -07001372 up_write(&mm->mmap_sem);
1373 return retval;
1374}
1375
1376#ifdef CONFIG_PROC_FS
Mike Waychison19b49462005-09-06 15:17:10 -07001377static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001378{
Eric W. Biederman1efdb692012-02-07 16:54:11 -08001379 struct user_namespace *user_ns = seq_user_ns(s);
Mike Waychison19b49462005-09-06 15:17:10 -07001380 struct shmid_kernel *shp = it;
Helge Dellerb7952182010-10-27 15:34:16 -07001381 unsigned long rss = 0, swp = 0;
1382
1383 shm_add_rss_swap(shp, &rss, &swp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001384
Paul Menage6c826812008-06-12 15:21:49 -07001385#if BITS_PER_LONG <= 32
1386#define SIZE_SPEC "%10lu"
1387#else
1388#define SIZE_SPEC "%21lu"
1389#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07001390
Joe Perches7f032d62015-04-15 16:17:54 -07001391 seq_printf(s,
1392 "%10d %10d %4o " SIZE_SPEC " %5u %5u "
1393 "%5lu %5u %5u %5u %5u %10lu %10lu %10lu "
1394 SIZE_SPEC " " SIZE_SPEC "\n",
1395 shp->shm_perm.key,
1396 shp->shm_perm.id,
1397 shp->shm_perm.mode,
1398 shp->shm_segsz,
1399 shp->shm_cprid,
1400 shp->shm_lprid,
1401 shp->shm_nattch,
1402 from_kuid_munged(user_ns, shp->shm_perm.uid),
1403 from_kgid_munged(user_ns, shp->shm_perm.gid),
1404 from_kuid_munged(user_ns, shp->shm_perm.cuid),
1405 from_kgid_munged(user_ns, shp->shm_perm.cgid),
1406 shp->shm_atim,
1407 shp->shm_dtim,
1408 shp->shm_ctim,
1409 rss * PAGE_SIZE,
1410 swp * PAGE_SIZE);
1411
1412 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001413}
1414#endif