1	// SPDX-License-Identifier: GPL-2.0
2	/*
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	*
17	* support for audit of ipc object properties and permission changes
18	* Dustin Kirkland <dustin.kirkland@us.ibm.com>
19	*
20	* namespaces support
21	* OpenVZ, SWsoft Inc.
22	* Pavel Emelianov <xemul@openvz.org>
23	*
24	* Better ipc lock (kern_ipc_perm.lock) handling
25	* Davidlohr Bueso <davidlohr.bueso@hp.com>, June 2013.
26	*/
27
28	#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>
35	#include <linux/shmem_fs.h>
36	#include <linux/security.h>
37	#include <linux/syscalls.h>
38	#include <linux/audit.h>
39	#include <linux/capability.h>
40	#include <linux/ptrace.h>
41	#include <linux/seq_file.h>
42	#include <linux/rwsem.h>
43	#include <linux/nsproxy.h>
44	#include <linux/mount.h>
45	#include <linux/ipc_namespace.h>
46	#include <linux/rhashtable.h>
47
48	#include <linux/uaccess.h>
49
50	#include "util.h"
51
52	struct 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;
61	struct pid *shm_cprid;
62	struct pid *shm_lprid;
63	struct ucounts *mlock_ucounts;
64
65	/*
66	* The task created the shm object, for
67	* task_lock(shp->shm_creator)
68	*/
69	struct task_struct *shm_creator;
70
71	/*
72	* List by creator. task_lock(->shm_creator) required for read/write.
73	* If list_empty(), then the creator is dead already.
74	*/
75	struct list_head shm_clist;
76	struct ipc_namespace *ns;
77	} __randomize_layout;
78
79	/* shm_mode upper byte flags */
80	#define SHM_DEST 01000 /* segment will be destroyed on last detach */
81	#define SHM_LOCKED 02000 /* segment will not be swapped */
82
83	struct shm_file_data {
84	int id;
85	struct ipc_namespace *ns;
86	struct file *file;
87	const struct vm_operations_struct *vm_ops;
88	};
89
90	#define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
91
92	static const struct file_operations shm_file_operations;
93	static const struct vm_operations_struct shm_vm_ops;
94
95	#define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS])
96
97	#define shm_unlock(shp) \
98	ipc_unlock(&(shp)->shm_perm)
99
100	static int newseg(struct ipc_namespace *, struct ipc_params *);
101	static void shm_open(struct vm_area_struct *vma);
102	static void shm_close(struct vm_area_struct *vma);
103	static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp);
104	#ifdef CONFIG_PROC_FS
105	static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
106	#endif
107
108	void shm_init_ns(struct ipc_namespace *ns)
109	{
110	ns->shm_ctlmax = SHMMAX;
111	ns->shm_ctlall = SHMALL;
112	ns->shm_ctlmni = SHMMNI;
113	ns->shm_rmid_forced = 0;
114	ns->shm_tot = 0;
115	ipc_init_ids(ids: &shm_ids(ns));
116	}
117
118	/*
119	* Called with shm_ids.rwsem (writer) and the shp structure locked.
120	* Only shm_ids.rwsem remains locked on exit.
121	*/
122	static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
123	{
124	struct shmid_kernel *shp;
125
126	shp = container_of(ipcp, struct shmid_kernel, shm_perm);
127	WARN_ON(ns != shp->ns);
128
129	if (shp->shm_nattch) {
130	shp->shm_perm.mode |= SHM_DEST;
131	/* Do not find it any more */
132	ipc_set_key_private(&shm_ids(ns), &shp->shm_perm);
133	shm_unlock(shp);
134	} else
135	shm_destroy(ns, shp);
136	}
137
138	#ifdef CONFIG_IPC_NS
139	void shm_exit_ns(struct ipc_namespace *ns)
140	{
141	free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
142	idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
143	rhashtable_destroy(&ns->ids[IPC_SHM_IDS].key_ht);
144	}
145	#endif
146
147	static int __init ipc_ns_init(void)
148	{
149	shm_init_ns(&init_ipc_ns);
150	return 0;
151	}
152
153	pure_initcall(ipc_ns_init);
154
155	void __init shm_init(void)
156	{
157	ipc_init_proc_interface("sysvipc/shm",
158	#if BITS_PER_LONG <= 32
159	" key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
160	#else
161	" key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
162	#endif
163	IPC_SHM_IDS, sysvipc_shm_proc_show);
164	}
165
166	static inline struct shmid_kernel *shm_obtain_object(struct ipc_namespace *ns, int id)
167	{
168	struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(ids: &shm_ids(ns), id);
169
170	if (IS_ERR(ptr: ipcp))
171	return ERR_CAST(ptr: ipcp);
172
173	return container_of(ipcp, struct shmid_kernel, shm_perm);
174	}
175
176	static inline struct shmid_kernel *shm_obtain_object_check(struct ipc_namespace *ns, int id)
177	{
178	struct kern_ipc_perm *ipcp = ipc_obtain_object_check(ids: &shm_ids(ns), id);
179
180	if (IS_ERR(ptr: ipcp))
181	return ERR_CAST(ptr: ipcp);
182
183	return container_of(ipcp, struct shmid_kernel, shm_perm);
184	}
185
186	/*
187	* shm_lock_(check_) routines are called in the paths where the rwsem
188	* is not necessarily held.
189	*/
190	static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
191	{
192	struct kern_ipc_perm *ipcp;
193
194	rcu_read_lock();
195	ipcp = ipc_obtain_object_idr(ids: &shm_ids(ns), id);
196	if (IS_ERR(ptr: ipcp))
197	goto err;
198
199	ipc_lock_object(perm: ipcp);
200	/*
201	* ipc_rmid() may have already freed the ID while ipc_lock_object()
202	* was spinning: here verify that the structure is still valid.
203	* Upon races with RMID, return -EIDRM, thus indicating that
204	* the ID points to a removed identifier.
205	*/
206	if (ipc_valid_object(perm: ipcp)) {
207	/* return a locked ipc object upon success */
208	return container_of(ipcp, struct shmid_kernel, shm_perm);
209	}
210
211	ipc_unlock_object(perm: ipcp);
212	ipcp = ERR_PTR(-EIDRM);
213	err:
214	rcu_read_unlock();
215	/*
216	* Callers of shm_lock() must validate the status of the returned ipc
217	* object pointer and error out as appropriate.
218	*/
219	return ERR_CAST(ptr: ipcp);
220	}
221
222	static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
223	{
224	rcu_read_lock();
225	ipc_lock_object(perm: &ipcp->shm_perm);
226	}
227
228	static void shm_rcu_free(struct rcu_head *head)
229	{
230	struct kern_ipc_perm *ptr = container_of(head, struct kern_ipc_perm,
231	rcu);
232	struct shmid_kernel *shp = container_of(ptr, struct shmid_kernel,
233	shm_perm);
234	security_shm_free(shp: &shp->shm_perm);
235	kfree(objp: shp);
236	}
237
238	/*
239	* It has to be called with shp locked.
240	* It must be called before ipc_rmid()
241	*/
242	static inline void shm_clist_rm(struct shmid_kernel *shp)
243	{
244	struct task_struct *creator;
245
246	/* ensure that shm_creator does not disappear */
247	rcu_read_lock();
248
249	/*
250	* A concurrent exit_shm may do a list_del_init() as well.
251	* Just do nothing if exit_shm already did the work
252	*/
253	if (!list_empty(head: &shp->shm_clist)) {
254	/*
255	* shp->shm_creator is guaranteed to be valid *only*
256	* if shp->shm_clist is not empty.
257	*/
258	creator = shp->shm_creator;
259
260	task_lock(p: creator);
261	/*
262	* list_del_init() is a nop if the entry was already removed
263	* from the list.
264	*/
265	list_del_init(entry: &shp->shm_clist);
266	task_unlock(p: creator);
267	}
268	rcu_read_unlock();
269	}
270
271	static inline void shm_rmid(struct shmid_kernel *s)
272	{
273	shm_clist_rm(shp: s);
274	ipc_rmid(&shm_ids(s->ns), &s->shm_perm);
275	}
276
277
278	static int __shm_open(struct shm_file_data *sfd)
279	{
280	struct shmid_kernel *shp;
281
282	shp = shm_lock(ns: sfd->ns, id: sfd->id);
283
284	if (IS_ERR(ptr: shp))
285	return PTR_ERR(ptr: shp);
286
287	if (shp->shm_file != sfd->file) {
288	/* ID was reused */
289	shm_unlock(shp);
290	return -EINVAL;
291	}
292
293	shp->shm_atim = ktime_get_real_seconds();
294	ipc_update_pid(pos: &shp->shm_lprid, pid: task_tgid(current));
295	shp->shm_nattch++;
296	shm_unlock(shp);
297	return 0;
298	}
299
300	/* This is called by fork, once for every shm attach. */
301	static void shm_open(struct vm_area_struct *vma)
302	{
303	struct file *file = vma->vm_file;
304	struct shm_file_data *sfd = shm_file_data(file);
305	int err;
306
307	/* Always call underlying open if present */
308	if (sfd->vm_ops->open)
309	sfd->vm_ops->open(vma);
310
311	err = __shm_open(sfd);
312	/*
313	* We raced in the idr lookup or with shm_destroy().
314	* Either way, the ID is busted.
315	*/
316	WARN_ON_ONCE(err);
317	}
318
319	/*
320	* shm_destroy - free the struct shmid_kernel
321	*
322	* @ns: namespace
323	* @shp: struct to free
324	*
325	* It has to be called with shp and shm_ids.rwsem (writer) locked,
326	* but returns with shp unlocked and freed.
327	*/
328	static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
329	{
330	struct file *shm_file;
331
332	shm_file = shp->shm_file;
333	shp->shm_file = NULL;
334	ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
335	shm_rmid(s: shp);
336	shm_unlock(shp);
337	if (!is_file_hugepages(shm_file))
338	shmem_lock(file: shm_file, lock: 0, ucounts: shp->mlock_ucounts);
339	fput(shm_file);
340	ipc_update_pid(pos: &shp->shm_cprid, NULL);
341	ipc_update_pid(pos: &shp->shm_lprid, NULL);
342	ipc_rcu_putref(ptr: &shp->shm_perm, func: shm_rcu_free);
343	}
344
345	/*
346	* shm_may_destroy - identifies whether shm segment should be destroyed now
347	*
348	* Returns true if and only if there are no active users of the segment and
349	* one of the following is true:
350	*
351	* 1) shmctl(id, IPC_RMID, NULL) was called for this shp
352	*
353	* 2) sysctl kernel.shm_rmid_forced is set to 1.
354	*/
355	static bool shm_may_destroy(struct shmid_kernel *shp)
356	{
357	return (shp->shm_nattch == 0) &&
358	(shp->ns->shm_rmid_forced ||
359	(shp->shm_perm.mode & SHM_DEST));
360	}
361
362	/*
363	* remove the attach descriptor vma.
364	* free memory for segment if it is marked destroyed.
365	* The descriptor has already been removed from the current->mm->mmap list
366	* and will later be kfree()d.
367	*/
368	static void __shm_close(struct shm_file_data *sfd)
369	{
370	struct shmid_kernel *shp;
371	struct ipc_namespace *ns = sfd->ns;
372
373	down_write(sem: &shm_ids(ns).rwsem);
374	/* remove from the list of attaches of the shm segment */
375	shp = shm_lock(ns, id: sfd->id);
376
377	/*
378	* We raced in the idr lookup or with shm_destroy().
379	* Either way, the ID is busted.
380	*/
381	if (WARN_ON_ONCE(IS_ERR(shp)))
382	goto done; /* no-op */
383
384	ipc_update_pid(pos: &shp->shm_lprid, pid: task_tgid(current));
385	shp->shm_dtim = ktime_get_real_seconds();
386	shp->shm_nattch--;
387	if (shm_may_destroy(shp))
388	shm_destroy(ns, shp);
389	else
390	shm_unlock(shp);
391	done:
392	up_write(sem: &shm_ids(ns).rwsem);
393	}
394
395	static void shm_close(struct vm_area_struct *vma)
396	{
397	struct file *file = vma->vm_file;
398	struct shm_file_data *sfd = shm_file_data(file);
399
400	/* Always call underlying close if present */
401	if (sfd->vm_ops->close)
402	sfd->vm_ops->close(vma);
403
404	__shm_close(sfd);
405	}
406
407	/* Called with ns->shm_ids(ns).rwsem locked */
408	static int shm_try_destroy_orphaned(int id, void *p, void *data)
409	{
410	struct ipc_namespace *ns = data;
411	struct kern_ipc_perm *ipcp = p;
412	struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
413
414	/*
415	* We want to destroy segments without users and with already
416	* exit'ed originating process.
417	*
418	* As shp->* are changed under rwsem, it's safe to skip shp locking.
419	*/
420	if (!list_empty(head: &shp->shm_clist))
421	return 0;
422
423	if (shm_may_destroy(shp)) {
424	shm_lock_by_ptr(ipcp: shp);
425	shm_destroy(ns, shp);
426	}
427	return 0;
428	}
429
430	void shm_destroy_orphaned(struct ipc_namespace *ns)
431	{
432	down_write(sem: &shm_ids(ns).rwsem);
433	if (shm_ids(ns).in_use)
434	idr_for_each(&shm_ids(ns).ipcs_idr, fn: &shm_try_destroy_orphaned, data: ns);
435	up_write(sem: &shm_ids(ns).rwsem);
436	}
437
438	/* Locking assumes this will only be called with task == current */
439	void exit_shm(struct task_struct *task)
440	{
441	for (;;) {
442	struct shmid_kernel *shp;
443	struct ipc_namespace *ns;
444
445	task_lock(p: task);
446
447	if (list_empty(head: &task->sysvshm.shm_clist)) {
448	task_unlock(p: task);
449	break;
450	}
451
452	shp = list_first_entry(&task->sysvshm.shm_clist, struct shmid_kernel,
453	shm_clist);
454
455	/*
456	* 1) Get pointer to the ipc namespace. It is worth to say
457	* that this pointer is guaranteed to be valid because
458	* shp lifetime is always shorter than namespace lifetime
459	* in which shp lives.
460	* We taken task_lock it means that shp won't be freed.
461	*/
462	ns = shp->ns;
463
464	/*
465	* 2) If kernel.shm_rmid_forced is not set then only keep track of
466	* which shmids are orphaned, so that a later set of the sysctl
467	* can clean them up.
468	*/
469	if (!ns->shm_rmid_forced)
470	goto unlink_continue;
471
472	/*
473	* 3) get a reference to the namespace.
474	* The refcount could be already 0. If it is 0, then
475	* the shm objects will be free by free_ipc_work().
476	*/
477	ns = get_ipc_ns_not_zero(ns);
478	if (!ns) {
479	unlink_continue:
480	list_del_init(entry: &shp->shm_clist);
481	task_unlock(p: task);
482	continue;
483	}
484
485	/*
486	* 4) get a reference to shp.
487	* This cannot fail: shm_clist_rm() is called before
488	* ipc_rmid(), thus the refcount cannot be 0.
489	*/
490	WARN_ON(!ipc_rcu_getref(&shp->shm_perm));
491
492	/*
493	* 5) unlink the shm segment from the list of segments
494	* created by current.
495	* This must be done last. After unlinking,
496	* only the refcounts obtained above prevent IPC_RMID
497	* from destroying the segment or the namespace.
498	*/
499	list_del_init(entry: &shp->shm_clist);
500
501	task_unlock(p: task);
502
503	/*
504	* 6) we have all references
505	* Thus lock & if needed destroy shp.
506	*/
507	down_write(sem: &shm_ids(ns).rwsem);
508	shm_lock_by_ptr(ipcp: shp);
509	/*
510	* rcu_read_lock was implicitly taken in shm_lock_by_ptr, it's
511	* safe to call ipc_rcu_putref here
512	*/
513	ipc_rcu_putref(ptr: &shp->shm_perm, func: shm_rcu_free);
514
515	if (ipc_valid_object(perm: &shp->shm_perm)) {
516	if (shm_may_destroy(shp))
517	shm_destroy(ns, shp);
518	else
519	shm_unlock(shp);
520	} else {
521	/*
522	* Someone else deleted the shp from namespace
523	* idr/kht while we have waited.
524	* Just unlock and continue.
525	*/
526	shm_unlock(shp);
527	}
528
529	up_write(sem: &shm_ids(ns).rwsem);
530	put_ipc_ns(ns); /* paired with get_ipc_ns_not_zero */
531	}
532	}
533
534	static vm_fault_t shm_fault(struct vm_fault *vmf)
535	{
536	struct file *file = vmf->vma->vm_file;
537	struct shm_file_data *sfd = shm_file_data(file);
538
539	return sfd->vm_ops->fault(vmf);
540	}
541
542	static int shm_may_split(struct vm_area_struct *vma, unsigned long addr)
543	{
544	struct file *file = vma->vm_file;
545	struct shm_file_data *sfd = shm_file_data(file);
546
547	if (sfd->vm_ops->may_split)
548	return sfd->vm_ops->may_split(vma, addr);
549
550	return 0;
551	}
552
553	static unsigned long shm_pagesize(struct vm_area_struct *vma)
554	{
555	struct file *file = vma->vm_file;
556	struct shm_file_data *sfd = shm_file_data(file);
557
558	if (sfd->vm_ops->pagesize)
559	return sfd->vm_ops->pagesize(vma);
560
561	return PAGE_SIZE;
562	}
563
564	#ifdef CONFIG_NUMA
565	static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
566	{
567	struct file *file = vma->vm_file;
568	struct shm_file_data *sfd = shm_file_data(file);
569	int err = 0;
570
571	if (sfd->vm_ops->set_policy)
572	err = sfd->vm_ops->set_policy(vma, new);
573	return err;
574	}
575
576	static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
577	unsigned long addr)
578	{
579	struct file *file = vma->vm_file;
580	struct shm_file_data *sfd = shm_file_data(file);
581	struct mempolicy *pol = NULL;
582
583	if (sfd->vm_ops->get_policy)
584	pol = sfd->vm_ops->get_policy(vma, addr);
585	else if (vma->vm_policy)
586	pol = vma->vm_policy;
587
588	return pol;
589	}
590	#endif
591
592	static int shm_mmap(struct file *file, struct vm_area_struct *vma)
593	{
594	struct shm_file_data *sfd = shm_file_data(file);
595	int ret;
596
597	/*
598	* In case of remap_file_pages() emulation, the file can represent an
599	* IPC ID that was removed, and possibly even reused by another shm
600	* segment already. Propagate this case as an error to caller.
601	*/
602	ret = __shm_open(sfd);
603	if (ret)
604	return ret;
605
606	ret = call_mmap(file: sfd->file, vma);
607	if (ret) {
608	__shm_close(sfd);
609	return ret;
610	}
611	sfd->vm_ops = vma->vm_ops;
612	#ifdef CONFIG_MMU
613	WARN_ON(!sfd->vm_ops->fault);
614	#endif
615	vma->vm_ops = &shm_vm_ops;
616	return 0;
617	}
618
619	static int shm_release(struct inode *ino, struct file *file)
620	{
621	struct shm_file_data *sfd = shm_file_data(file);
622
623	put_ipc_ns(ns: sfd->ns);
624	fput(sfd->file);
625	shm_file_data(file) = NULL;
626	kfree(objp: sfd);
627	return 0;
628	}
629
630	static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
631	{
632	struct shm_file_data *sfd = shm_file_data(file);
633
634	if (!sfd->file->f_op->fsync)
635	return -EINVAL;
636	return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
637	}
638
639	static long shm_fallocate(struct file *file, int mode, loff_t offset,
640	loff_t len)
641	{
642	struct shm_file_data *sfd = shm_file_data(file);
643
644	if (!sfd->file->f_op->fallocate)
645	return -EOPNOTSUPP;
646	return sfd->file->f_op->fallocate(file, mode, offset, len);
647	}
648
649	static unsigned long shm_get_unmapped_area(struct file *file,
650	unsigned long addr, unsigned long len, unsigned long pgoff,
651	unsigned long flags)
652	{
653	struct shm_file_data *sfd = shm_file_data(file);
654
655	return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
656	pgoff, flags);
657	}
658
659	static const struct file_operations shm_file_operations = {
660	.mmap = shm_mmap,
661	.fsync = shm_fsync,
662	.release = shm_release,
663	.get_unmapped_area = shm_get_unmapped_area,
664	.llseek = noop_llseek,
665	.fallocate = shm_fallocate,
666	};
667
668	/*
669	* shm_file_operations_huge is now identical to shm_file_operations,
670	* but we keep it distinct for the sake of is_file_shm_hugepages().
671	*/
672	static const struct file_operations shm_file_operations_huge = {
673	.mmap = shm_mmap,
674	.fsync = shm_fsync,
675	.release = shm_release,
676	.get_unmapped_area = shm_get_unmapped_area,
677	.llseek = noop_llseek,
678	.fallocate = shm_fallocate,
679	};
680
681	bool is_file_shm_hugepages(struct file *file)
682	{
683	return file->f_op == &shm_file_operations_huge;
684	}
685
686	static const struct vm_operations_struct shm_vm_ops = {
687	.open = shm_open, /* callback for a new vm-area open */
688	.close = shm_close, /* callback for when the vm-area is released */
689	.fault = shm_fault,
690	.may_split = shm_may_split,
691	.pagesize = shm_pagesize,
692	#if defined(CONFIG_NUMA)
693	.set_policy = shm_set_policy,
694	.get_policy = shm_get_policy,
695	#endif
696	};
697
698	/**
699	* newseg - Create a new shared memory segment
700	* @ns: namespace
701	* @params: ptr to the structure that contains key, size and shmflg
702	*
703	* Called with shm_ids.rwsem held as a writer.
704	*/
705	static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
706	{
707	key_t key = params->key;
708	int shmflg = params->flg;
709	size_t size = params->u.size;
710	int error;
711	struct shmid_kernel *shp;
712	size_t numpages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
713	struct file *file;
714	char name[13];
715	vm_flags_t acctflag = 0;
716
717	if (size < SHMMIN || size > ns->shm_ctlmax)
718	return -EINVAL;
719
720	if (numpages << PAGE_SHIFT < size)
721	return -ENOSPC;
722
723	if (ns->shm_tot + numpages < ns->shm_tot ||
724	ns->shm_tot + numpages > ns->shm_ctlall)
725	return -ENOSPC;
726
727	shp = kmalloc(size: sizeof(*shp), GFP_KERNEL_ACCOUNT);
728	if (unlikely(!shp))
729	return -ENOMEM;
730
731	shp->shm_perm.key = key;
732	shp->shm_perm.mode = (shmflg & S_IRWXUGO);
733	shp->mlock_ucounts = NULL;
734
735	shp->shm_perm.security = NULL;
736	error = security_shm_alloc(shp: &shp->shm_perm);
737	if (error) {
738	kfree(objp: shp);
739	return error;
740	}
741
742	sprintf(buf: name, fmt: "SYSV%08x", key);
743	if (shmflg & SHM_HUGETLB) {
744	struct hstate *hs;
745	size_t hugesize;
746
747	hs = hstate_sizelog(page_size_log: (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
748	if (!hs) {
749	error = -EINVAL;
750	goto no_file;
751	}
752	hugesize = ALIGN(size, huge_page_size(hs));
753
754	/* hugetlb_file_setup applies strict accounting */
755	if (shmflg & SHM_NORESERVE)
756	acctflag = VM_NORESERVE;
757	file = hugetlb_file_setup(name, size: hugesize, acctflag,
758	creat_flags: HUGETLB_SHMFS_INODE, page_size_log: (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
759	} else {
760	/*
761	* Do not allow no accounting for OVERCOMMIT_NEVER, even
762	* if it's asked for.
763	*/
764	if ((shmflg & SHM_NORESERVE) &&
765	sysctl_overcommit_memory != OVERCOMMIT_NEVER)
766	acctflag = VM_NORESERVE;
767	file = shmem_kernel_file_setup(name, size, flags: acctflag);
768	}
769	error = PTR_ERR(ptr: file);
770	if (IS_ERR(ptr: file))
771	goto no_file;
772
773	shp->shm_cprid = get_pid(pid: task_tgid(current));
774	shp->shm_lprid = NULL;
775	shp->shm_atim = shp->shm_dtim = 0;
776	shp->shm_ctim = ktime_get_real_seconds();
777	shp->shm_segsz = size;
778	shp->shm_nattch = 0;
779	shp->shm_file = file;
780	shp->shm_creator = current;
781
782	/* ipc_addid() locks shp upon success. */
783	error = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
784	if (error < 0)
785	goto no_id;
786
787	shp->ns = ns;
788
789	task_lock(current);
790	list_add(new: &shp->shm_clist, head: &current->sysvshm.shm_clist);
791	task_unlock(current);
792
793	/*
794	* shmid gets reported as "inode#" in /proc/pid/maps.
795	* proc-ps tools use this. Changing this will break them.
796	*/
797	file_inode(f: file)->i_ino = shp->shm_perm.id;
798
799	ns->shm_tot += numpages;
800	error = shp->shm_perm.id;
801
802	ipc_unlock_object(perm: &shp->shm_perm);
803	rcu_read_unlock();
804	return error;
805
806	no_id:
807	ipc_update_pid(pos: &shp->shm_cprid, NULL);
808	ipc_update_pid(pos: &shp->shm_lprid, NULL);
809	fput(file);
810	ipc_rcu_putref(ptr: &shp->shm_perm, func: shm_rcu_free);
811	return error;
812	no_file:
813	call_rcu(head: &shp->shm_perm.rcu, func: shm_rcu_free);
814	return error;
815	}
816
817	/*
818	* Called with shm_ids.rwsem and ipcp locked.
819	*/
820	static int shm_more_checks(struct kern_ipc_perm *ipcp, struct ipc_params *params)
821	{
822	struct shmid_kernel *shp;
823
824	shp = container_of(ipcp, struct shmid_kernel, shm_perm);
825	if (shp->shm_segsz < params->u.size)
826	return -EINVAL;
827
828	return 0;
829	}
830
831	long ksys_shmget(key_t key, size_t size, int shmflg)
832	{
833	struct ipc_namespace *ns;
834	static const struct ipc_ops shm_ops = {
835	.getnew = newseg,
836	.associate = security_shm_associate,
837	.more_checks = shm_more_checks,
838	};
839	struct ipc_params shm_params;
840
841	ns = current->nsproxy->ipc_ns;
842
843	shm_params.key = key;
844	shm_params.flg = shmflg;
845	shm_params.u.size = size;
846
847	return ipcget(ns, ids: &shm_ids(ns), ops: &shm_ops, params: &shm_params);
848	}
849
850	SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
851	{
852	return ksys_shmget(key, size, shmflg);
853	}
854
855	static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
856	{
857	switch (version) {
858	case IPC_64:
859	return copy_to_user(to: buf, from: in, n: sizeof(*in));
860	case IPC_OLD:
861	{
862	struct shmid_ds out;
863
864	memset(s: &out, c: 0, n: sizeof(out));
865	ipc64_perm_to_ipc_perm(in: &in->shm_perm, out: &out.shm_perm);
866	out.shm_segsz = in->shm_segsz;
867	out.shm_atime = in->shm_atime;
868	out.shm_dtime = in->shm_dtime;
869	out.shm_ctime = in->shm_ctime;
870	out.shm_cpid = in->shm_cpid;
871	out.shm_lpid = in->shm_lpid;
872	out.shm_nattch = in->shm_nattch;
873
874	return copy_to_user(to: buf, from: &out, n: sizeof(out));
875	}
876	default:
877	return -EINVAL;
878	}
879	}
880
881	static inline unsigned long
882	copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
883	{
884	switch (version) {
885	case IPC_64:
886	if (copy_from_user(out, buf, sizeof(*out)))
887	return -EFAULT;
888	return 0;
889	case IPC_OLD:
890	{
891	struct shmid_ds tbuf_old;
892
893	if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
894	return -EFAULT;
895
896	out->shm_perm.uid = tbuf_old.shm_perm.uid;
897	out->shm_perm.gid = tbuf_old.shm_perm.gid;
898	out->shm_perm.mode = tbuf_old.shm_perm.mode;
899
900	return 0;
901	}
902	default:
903	return -EINVAL;
904	}
905	}
906
907	static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
908	{
909	switch (version) {
910	case IPC_64:
911	return copy_to_user(to: buf, from: in, n: sizeof(*in));
912	case IPC_OLD:
913	{
914	struct shminfo out;
915
916	if (in->shmmax > INT_MAX)
917	out.shmmax = INT_MAX;
918	else
919	out.shmmax = (int)in->shmmax;
920
921	out.shmmin = in->shmmin;
922	out.shmmni = in->shmmni;
923	out.shmseg = in->shmseg;
924	out.shmall = in->shmall;
925
926	return copy_to_user(to: buf, from: &out, n: sizeof(out));
927	}
928	default:
929	return -EINVAL;
930	}
931	}
932
933	/*
934	* Calculate and add used RSS and swap pages of a shm.
935	* Called with shm_ids.rwsem held as a reader
936	*/
937	static void shm_add_rss_swap(struct shmid_kernel *shp,
938	unsigned long *rss_add, unsigned long *swp_add)
939	{
940	struct inode *inode;
941
942	inode = file_inode(f: shp->shm_file);
943
944	if (is_file_hugepages(shp->shm_file)) {
945	struct address_space *mapping = inode->i_mapping;
946	struct hstate *h = hstate_file(f: shp->shm_file);
947	*rss_add += pages_per_huge_page(h) * mapping->nrpages;
948	} else {
949	#ifdef CONFIG_SHMEM
950	struct shmem_inode_info *info = SHMEM_I(inode);
951
952	spin_lock_irq(&info->lock);
953	*rss_add += inode->i_mapping->nrpages;
954	*swp_add += info->swapped;
955	spin_unlock_irq(&info->lock);
956	#else
957	*rss_add += inode->i_mapping->nrpages;
958	#endif
959	}
960	}
961
962	/*
963	* Called with shm_ids.rwsem held as a reader
964	*/
965	static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
966	unsigned long *swp)
967	{
968	int next_id;
969	int total, in_use;
970
971	*rss = 0;
972	*swp = 0;
973
974	in_use = shm_ids(ns).in_use;
975
976	for (total = 0, next_id = 0; total < in_use; next_id++) {
977	struct kern_ipc_perm *ipc;
978	struct shmid_kernel *shp;
979
980	ipc = idr_find(&shm_ids(ns).ipcs_idr, id: next_id);
981	if (ipc == NULL)
982	continue;
983	shp = container_of(ipc, struct shmid_kernel, shm_perm);
984
985	shm_add_rss_swap(shp, rss_add: rss, swp_add: swp);
986
987	total++;
988	}
989	}
990
991	/*
992	* This function handles some shmctl commands which require the rwsem
993	* to be held in write mode.
994	* NOTE: no locks must be held, the rwsem is taken inside this function.
995	*/
996	static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
997	struct shmid64_ds *shmid64)
998	{
999	struct kern_ipc_perm *ipcp;
1000	struct shmid_kernel *shp;
1001	int err;
1002
1003	down_write(sem: &shm_ids(ns).rwsem);
1004	rcu_read_lock();
1005
1006	ipcp = ipcctl_obtain_check(ns, ids: &shm_ids(ns), id: shmid, cmd,
1007	perm: &shmid64->shm_perm, extra_perm: 0);
1008	if (IS_ERR(ptr: ipcp)) {
1009	err = PTR_ERR(ptr: ipcp);
1010	goto out_unlock1;
1011	}
1012
1013	shp = container_of(ipcp, struct shmid_kernel, shm_perm);
1014
1015	err = security_shm_shmctl(shp: &shp->shm_perm, cmd);
1016	if (err)
1017	goto out_unlock1;
1018
1019	switch (cmd) {
1020	case IPC_RMID:
1021	ipc_lock_object(perm: &shp->shm_perm);
1022	/* do_shm_rmid unlocks the ipc object and rcu */
1023	do_shm_rmid(ns, ipcp);
1024	goto out_up;
1025	case IPC_SET:
1026	ipc_lock_object(perm: &shp->shm_perm);
1027	err = ipc_update_perm(in: &shmid64->shm_perm, out: ipcp);
1028	if (err)
1029	goto out_unlock0;
1030	shp->shm_ctim = ktime_get_real_seconds();
1031	break;
1032	default:
1033	err = -EINVAL;
1034	goto out_unlock1;
1035	}
1036
1037	out_unlock0:
1038	ipc_unlock_object(perm: &shp->shm_perm);
1039	out_unlock1:
1040	rcu_read_unlock();
1041	out_up:
1042	up_write(sem: &shm_ids(ns).rwsem);
1043	return err;
1044	}
1045
1046	static int shmctl_ipc_info(struct ipc_namespace *ns,
1047	struct shminfo64 *shminfo)
1048	{
1049	int err = security_shm_shmctl(NULL, IPC_INFO);
1050	if (!err) {
1051	memset(s: shminfo, c: 0, n: sizeof(*shminfo));
1052	shminfo->shmmni = shminfo->shmseg = ns->shm_ctlmni;
1053	shminfo->shmmax = ns->shm_ctlmax;
1054	shminfo->shmall = ns->shm_ctlall;
1055	shminfo->shmmin = SHMMIN;
1056	down_read(sem: &shm_ids(ns).rwsem);
1057	err = ipc_get_maxidx(ids: &shm_ids(ns));
1058	up_read(sem: &shm_ids(ns).rwsem);
1059	if (err < 0)
1060	err = 0;
1061	}
1062	return err;
1063	}
1064
1065	static int shmctl_shm_info(struct ipc_namespace *ns,
1066	struct shm_info *shm_info)
1067	{
1068	int err = security_shm_shmctl(NULL, SHM_INFO);
1069	if (!err) {
1070	memset(s: shm_info, c: 0, n: sizeof(*shm_info));
1071	down_read(sem: &shm_ids(ns).rwsem);
1072	shm_info->used_ids = shm_ids(ns).in_use;
1073	shm_get_stat(ns, rss: &shm_info->shm_rss, swp: &shm_info->shm_swp);
1074	shm_info->shm_tot = ns->shm_tot;
1075	shm_info->swap_attempts = 0;
1076	shm_info->swap_successes = 0;
1077	err = ipc_get_maxidx(ids: &shm_ids(ns));
1078	up_read(sem: &shm_ids(ns).rwsem);
1079	if (err < 0)
1080	err = 0;
1081	}
1082	return err;
1083	}
1084
1085	static int shmctl_stat(struct ipc_namespace *ns, int shmid,
1086	int cmd, struct shmid64_ds *tbuf)
1087	{
1088	struct shmid_kernel *shp;
1089	int err;
1090
1091	memset(s: tbuf, c: 0, n: sizeof(*tbuf));
1092
1093	rcu_read_lock();
1094	if (cmd == SHM_STAT || cmd == SHM_STAT_ANY) {
1095	shp = shm_obtain_object(ns, id: shmid);
1096	if (IS_ERR(ptr: shp)) {
1097	err = PTR_ERR(ptr: shp);
1098	goto out_unlock;
1099	}
1100	} else { /* IPC_STAT */
1101	shp = shm_obtain_object_check(ns, id: shmid);
1102	if (IS_ERR(ptr: shp)) {
1103	err = PTR_ERR(ptr: shp);
1104	goto out_unlock;
1105	}
1106	}
1107
1108	/*
1109	* Semantically SHM_STAT_ANY ought to be identical to
1110	* that functionality provided by the /proc/sysvipc/
1111	* interface. As such, only audit these calls and
1112	* do not do traditional S_IRUGO permission checks on
1113	* the ipc object.
1114	*/
1115	if (cmd == SHM_STAT_ANY)
1116	audit_ipc_obj(ipcp: &shp->shm_perm);
1117	else {
1118	err = -EACCES;
1119	if (ipcperms(ns, ipcp: &shp->shm_perm, S_IRUGO))
1120	goto out_unlock;
1121	}
1122
1123	err = security_shm_shmctl(shp: &shp->shm_perm, cmd);
1124	if (err)
1125	goto out_unlock;
1126
1127	ipc_lock_object(perm: &shp->shm_perm);
1128
1129	if (!ipc_valid_object(perm: &shp->shm_perm)) {
1130	ipc_unlock_object(perm: &shp->shm_perm);
1131	err = -EIDRM;
1132	goto out_unlock;
1133	}
1134
1135	kernel_to_ipc64_perm(in: &shp->shm_perm, out: &tbuf->shm_perm);
1136	tbuf->shm_segsz = shp->shm_segsz;
1137	tbuf->shm_atime = shp->shm_atim;
1138	tbuf->shm_dtime = shp->shm_dtim;
1139	tbuf->shm_ctime = shp->shm_ctim;
1140	#ifndef CONFIG_64BIT
1141	tbuf->shm_atime_high = shp->shm_atim >> 32;
1142	tbuf->shm_dtime_high = shp->shm_dtim >> 32;
1143	tbuf->shm_ctime_high = shp->shm_ctim >> 32;
1144	#endif
1145	tbuf->shm_cpid = pid_vnr(pid: shp->shm_cprid);
1146	tbuf->shm_lpid = pid_vnr(pid: shp->shm_lprid);
1147	tbuf->shm_nattch = shp->shm_nattch;
1148
1149	if (cmd == IPC_STAT) {
1150	/*
1151	* As defined in SUS:
1152	* Return 0 on success
1153	*/
1154	err = 0;
1155	} else {
1156	/*
1157	* SHM_STAT and SHM_STAT_ANY (both Linux specific)
1158	* Return the full id, including the sequence number
1159	*/
1160	err = shp->shm_perm.id;
1161	}
1162
1163	ipc_unlock_object(perm: &shp->shm_perm);
1164	out_unlock:
1165	rcu_read_unlock();
1166	return err;
1167	}
1168
1169	static int shmctl_do_lock(struct ipc_namespace *ns, int shmid, int cmd)
1170	{
1171	struct shmid_kernel *shp;
1172	struct file *shm_file;
1173	int err;
1174
1175	rcu_read_lock();
1176	shp = shm_obtain_object_check(ns, id: shmid);
1177	if (IS_ERR(ptr: shp)) {
1178	err = PTR_ERR(ptr: shp);
1179	goto out_unlock1;
1180	}
1181
1182	audit_ipc_obj(ipcp: &(shp->shm_perm));
1183	err = security_shm_shmctl(shp: &shp->shm_perm, cmd);
1184	if (err)
1185	goto out_unlock1;
1186
1187	ipc_lock_object(perm: &shp->shm_perm);
1188
1189	/* check if shm_destroy() is tearing down shp */
1190	if (!ipc_valid_object(perm: &shp->shm_perm)) {
1191	err = -EIDRM;
1192	goto out_unlock0;
1193	}
1194
1195	if (!ns_capable(ns: ns->user_ns, CAP_IPC_LOCK)) {
1196	kuid_t euid = current_euid();
1197
1198	if (!uid_eq(left: euid, right: shp->shm_perm.uid) &&
1199	!uid_eq(left: euid, right: shp->shm_perm.cuid)) {
1200	err = -EPERM;
1201	goto out_unlock0;
1202	}
1203	if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) {
1204	err = -EPERM;
1205	goto out_unlock0;
1206	}
1207	}
1208
1209	shm_file = shp->shm_file;
1210	if (is_file_hugepages(shm_file))
1211	goto out_unlock0;
1212
1213	if (cmd == SHM_LOCK) {
1214	struct ucounts *ucounts = current_ucounts();
1215
1216	err = shmem_lock(file: shm_file, lock: 1, ucounts);
1217	if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
1218	shp->shm_perm.mode |= SHM_LOCKED;
1219	shp->mlock_ucounts = ucounts;
1220	}
1221	goto out_unlock0;
1222	}
1223
1224	/* SHM_UNLOCK */
1225	if (!(shp->shm_perm.mode & SHM_LOCKED))
1226	goto out_unlock0;
1227	shmem_lock(file: shm_file, lock: 0, ucounts: shp->mlock_ucounts);
1228	shp->shm_perm.mode &= ~SHM_LOCKED;
1229	shp->mlock_ucounts = NULL;
1230	get_file(f: shm_file);
1231	ipc_unlock_object(perm: &shp->shm_perm);
1232	rcu_read_unlock();
1233	shmem_unlock_mapping(mapping: shm_file->f_mapping);
1234
1235	fput(shm_file);
1236	return err;
1237
1238	out_unlock0:
1239	ipc_unlock_object(perm: &shp->shm_perm);
1240	out_unlock1:
1241	rcu_read_unlock();
1242	return err;
1243	}
1244
1245	static long ksys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf, int version)
1246	{
1247	int err;
1248	struct ipc_namespace *ns;
1249	struct shmid64_ds sem64;
1250
1251	if (cmd < 0 || shmid < 0)
1252	return -EINVAL;
1253
1254	ns = current->nsproxy->ipc_ns;
1255
1256	switch (cmd) {
1257	case IPC_INFO: {
1258	struct shminfo64 shminfo;
1259	err = shmctl_ipc_info(ns, shminfo: &shminfo);
1260	if (err < 0)
1261	return err;
1262	if (copy_shminfo_to_user(buf, &shminfo, version))
1263	err = -EFAULT;
1264	return err;
1265	}
1266	case SHM_INFO: {
1267	struct shm_info shm_info;
1268	err = shmctl_shm_info(ns, shm_info: &shm_info);
1269	if (err < 0)
1270	return err;
1271	if (copy_to_user(buf, &shm_info, sizeof(shm_info)))
1272	err = -EFAULT;
1273	return err;
1274	}
1275	case SHM_STAT:
1276	case SHM_STAT_ANY:
1277	case IPC_STAT: {
1278	err = shmctl_stat(ns, shmid, cmd, tbuf: &sem64);
1279	if (err < 0)
1280	return err;
1281	if (copy_shmid_to_user(buf, &sem64, version))
1282	err = -EFAULT;
1283	return err;
1284	}
1285	case IPC_SET:
1286	if (copy_shmid_from_user(&sem64, buf, version))
1287	return -EFAULT;
1288	fallthrough;
1289	case IPC_RMID:
1290	return shmctl_down(ns, shmid, cmd, shmid64: &sem64);
1291	case SHM_LOCK:
1292	case SHM_UNLOCK:
1293	return shmctl_do_lock(ns, shmid, cmd);
1294	default:
1295	return -EINVAL;
1296	}
1297	}
1298
1299	SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
1300	{
1301	return ksys_shmctl(shmid, cmd, buf, IPC_64);
1302	}
1303
1304	#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
1305	long ksys_old_shmctl(int shmid, int cmd, struct shmid_ds __user *buf)
1306	{
1307	int version = ipc_parse_version(&cmd);
1308
1309	return ksys_shmctl(shmid, cmd, buf, version);
1310	}
1311
1312	SYSCALL_DEFINE3(old_shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
1313	{
1314	return ksys_old_shmctl(shmid, cmd, buf);
1315	}
1316	#endif
1317
1318	#ifdef CONFIG_COMPAT
1319
1320	struct compat_shmid_ds {
1321	struct compat_ipc_perm shm_perm;
1322	int shm_segsz;
1323	old_time32_t shm_atime;
1324	old_time32_t shm_dtime;
1325	old_time32_t shm_ctime;
1326	compat_ipc_pid_t shm_cpid;
1327	compat_ipc_pid_t shm_lpid;
1328	unsigned short shm_nattch;
1329	unsigned short shm_unused;
1330	compat_uptr_t shm_unused2;
1331	compat_uptr_t shm_unused3;
1332	};
1333
1334	struct compat_shminfo64 {
1335	compat_ulong_t shmmax;
1336	compat_ulong_t shmmin;
1337	compat_ulong_t shmmni;
1338	compat_ulong_t shmseg;
1339	compat_ulong_t shmall;
1340	compat_ulong_t __unused1;
1341	compat_ulong_t __unused2;
1342	compat_ulong_t __unused3;
1343	compat_ulong_t __unused4;
1344	};
1345
1346	struct compat_shm_info {
1347	compat_int_t used_ids;
1348	compat_ulong_t shm_tot, shm_rss, shm_swp;
1349	compat_ulong_t swap_attempts, swap_successes;
1350	};
1351
1352	static int copy_compat_shminfo_to_user(void __user *buf, struct shminfo64 *in,
1353	int version)
1354	{
1355	if (in->shmmax > INT_MAX)
1356	in->shmmax = INT_MAX;
1357	if (version == IPC_64) {
1358	struct compat_shminfo64 info;
1359	memset(&info, 0, sizeof(info));
1360	info.shmmax = in->shmmax;
1361	info.shmmin = in->shmmin;
1362	info.shmmni = in->shmmni;
1363	info.shmseg = in->shmseg;
1364	info.shmall = in->shmall;
1365	return copy_to_user(buf, &info, sizeof(info));
1366	} else {
1367	struct shminfo info;
1368	memset(&info, 0, sizeof(info));
1369	info.shmmax = in->shmmax;
1370	info.shmmin = in->shmmin;
1371	info.shmmni = in->shmmni;
1372	info.shmseg = in->shmseg;
1373	info.shmall = in->shmall;
1374	return copy_to_user(buf, &info, sizeof(info));
1375	}
1376	}
1377
1378	static int put_compat_shm_info(struct shm_info *ip,
1379	struct compat_shm_info __user *uip)
1380	{
1381	struct compat_shm_info info;
1382
1383	memset(&info, 0, sizeof(info));
1384	info.used_ids = ip->used_ids;
1385	info.shm_tot = ip->shm_tot;
1386	info.shm_rss = ip->shm_rss;
1387	info.shm_swp = ip->shm_swp;
1388	info.swap_attempts = ip->swap_attempts;
1389	info.swap_successes = ip->swap_successes;
1390	return copy_to_user(uip, &info, sizeof(info));
1391	}
1392
1393	static int copy_compat_shmid_to_user(void __user *buf, struct shmid64_ds *in,
1394	int version)
1395	{
1396	if (version == IPC_64) {
1397	struct compat_shmid64_ds v;
1398	memset(&v, 0, sizeof(v));
1399	to_compat_ipc64_perm(&v.shm_perm, &in->shm_perm);
1400	v.shm_atime = lower_32_bits(in->shm_atime);
1401	v.shm_atime_high = upper_32_bits(in->shm_atime);
1402	v.shm_dtime = lower_32_bits(in->shm_dtime);
1403	v.shm_dtime_high = upper_32_bits(in->shm_dtime);
1404	v.shm_ctime = lower_32_bits(in->shm_ctime);
1405	v.shm_ctime_high = upper_32_bits(in->shm_ctime);
1406	v.shm_segsz = in->shm_segsz;
1407	v.shm_nattch = in->shm_nattch;
1408	v.shm_cpid = in->shm_cpid;
1409	v.shm_lpid = in->shm_lpid;
1410	return copy_to_user(buf, &v, sizeof(v));
1411	} else {
1412	struct compat_shmid_ds v;
1413	memset(&v, 0, sizeof(v));
1414	to_compat_ipc_perm(&v.shm_perm, &in->shm_perm);
1415	v.shm_perm.key = in->shm_perm.key;
1416	v.shm_atime = in->shm_atime;
1417	v.shm_dtime = in->shm_dtime;
1418	v.shm_ctime = in->shm_ctime;
1419	v.shm_segsz = in->shm_segsz;
1420	v.shm_nattch = in->shm_nattch;
1421	v.shm_cpid = in->shm_cpid;
1422	v.shm_lpid = in->shm_lpid;
1423	return copy_to_user(buf, &v, sizeof(v));
1424	}
1425	}
1426
1427	static int copy_compat_shmid_from_user(struct shmid64_ds *out, void __user *buf,
1428	int version)
1429	{
1430	memset(out, 0, sizeof(*out));
1431	if (version == IPC_64) {
1432	struct compat_shmid64_ds __user *p = buf;
1433	return get_compat_ipc64_perm(&out->shm_perm, &p->shm_perm);
1434	} else {
1435	struct compat_shmid_ds __user *p = buf;
1436	return get_compat_ipc_perm(&out->shm_perm, &p->shm_perm);
1437	}
1438	}
1439
1440	static long compat_ksys_shmctl(int shmid, int cmd, void __user *uptr, int version)
1441	{
1442	struct ipc_namespace *ns;
1443	struct shmid64_ds sem64;
1444	int err;
1445
1446	ns = current->nsproxy->ipc_ns;
1447
1448	if (cmd < 0 || shmid < 0)
1449	return -EINVAL;
1450
1451	switch (cmd) {
1452	case IPC_INFO: {
1453	struct shminfo64 shminfo;
1454	err = shmctl_ipc_info(ns, &shminfo);
1455	if (err < 0)
1456	return err;
1457	if (copy_compat_shminfo_to_user(uptr, &shminfo, version))
1458	err = -EFAULT;
1459	return err;
1460	}
1461	case SHM_INFO: {
1462	struct shm_info shm_info;
1463	err = shmctl_shm_info(ns, &shm_info);
1464	if (err < 0)
1465	return err;
1466	if (put_compat_shm_info(&shm_info, uptr))
1467	err = -EFAULT;
1468	return err;
1469	}
1470	case IPC_STAT:
1471	case SHM_STAT_ANY:
1472	case SHM_STAT:
1473	err = shmctl_stat(ns, shmid, cmd, &sem64);
1474	if (err < 0)
1475	return err;
1476	if (copy_compat_shmid_to_user(uptr, &sem64, version))
1477	err = -EFAULT;
1478	return err;
1479
1480	case IPC_SET:
1481	if (copy_compat_shmid_from_user(&sem64, uptr, version))
1482	return -EFAULT;
1483	fallthrough;
1484	case IPC_RMID:
1485	return shmctl_down(ns, shmid, cmd, &sem64);
1486	case SHM_LOCK:
1487	case SHM_UNLOCK:
1488	return shmctl_do_lock(ns, shmid, cmd);
1489	default:
1490	return -EINVAL;
1491	}
1492	return err;
1493	}
1494
1495	COMPAT_SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, void __user *, uptr)
1496	{
1497	return compat_ksys_shmctl(shmid, cmd, uptr, IPC_64);
1498	}
1499
1500	#ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION
1501	long compat_ksys_old_shmctl(int shmid, int cmd, void __user *uptr)
1502	{
1503	int version = compat_ipc_parse_version(&cmd);
1504
1505	return compat_ksys_shmctl(shmid, cmd, uptr, version);
1506	}
1507
1508	COMPAT_SYSCALL_DEFINE3(old_shmctl, int, shmid, int, cmd, void __user *, uptr)
1509	{
1510	return compat_ksys_old_shmctl(shmid, cmd, uptr);
1511	}
1512	#endif
1513	#endif
1514
1515	/*
1516	* Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
1517	*
1518	* NOTE! Despite the name, this is NOT a direct system call entrypoint. The
1519	* "raddr" thing points to kernel space, and there has to be a wrapper around
1520	* this.
1521	*/
1522	long do_shmat(int shmid, char __user *shmaddr, int shmflg,
1523	ulong *raddr, unsigned long shmlba)
1524	{
1525	struct shmid_kernel *shp;
1526	unsigned long addr = (unsigned long)shmaddr;
1527	unsigned long size;
1528	struct file *file, *base;
1529	int err;
1530	unsigned long flags = MAP_SHARED;
1531	unsigned long prot;
1532	int acc_mode;
1533	struct ipc_namespace *ns;
1534	struct shm_file_data *sfd;
1535	int f_flags;
1536	unsigned long populate = 0;
1537
1538	err = -EINVAL;
1539	if (shmid < 0)
1540	goto out;
1541
1542	if (addr) {
1543	if (addr & (shmlba - 1)) {
1544	if (shmflg & SHM_RND) {
1545	addr &= ~(shmlba - 1); /* round down */
1546
1547	/*
1548	* Ensure that the round-down is non-nil
1549	* when remapping. This can happen for
1550	* cases when addr < shmlba.
1551	*/
1552	if (!addr && (shmflg & SHM_REMAP))
1553	goto out;
1554	} else
1555	#ifndef __ARCH_FORCE_SHMLBA
1556	if (addr & ~PAGE_MASK)
1557	#endif
1558	goto out;
1559	}
1560
1561	flags |= MAP_FIXED;
1562	} else if ((shmflg & SHM_REMAP))
1563	goto out;
1564
1565	if (shmflg & SHM_RDONLY) {
1566	prot = PROT_READ;
1567	acc_mode = S_IRUGO;
1568	f_flags = O_RDONLY;
1569	} else {
1570	prot = PROT_READ | PROT_WRITE;
1571	acc_mode = S_IRUGO | S_IWUGO;
1572	f_flags = O_RDWR;
1573	}
1574	if (shmflg & SHM_EXEC) {
1575	prot |= PROT_EXEC;
1576	acc_mode |= S_IXUGO;
1577	}
1578
1579	/*
1580	* We cannot rely on the fs check since SYSV IPC does have an
1581	* additional creator id...
1582	*/
1583	ns = current->nsproxy->ipc_ns;
1584	rcu_read_lock();
1585	shp = shm_obtain_object_check(ns, id: shmid);
1586	if (IS_ERR(ptr: shp)) {
1587	err = PTR_ERR(ptr: shp);
1588	goto out_unlock;
1589	}
1590
1591	err = -EACCES;
1592	if (ipcperms(ns, ipcp: &shp->shm_perm, flg: acc_mode))
1593	goto out_unlock;
1594
1595	err = security_shm_shmat(shp: &shp->shm_perm, shmaddr, shmflg);
1596	if (err)
1597	goto out_unlock;
1598
1599	ipc_lock_object(perm: &shp->shm_perm);
1600
1601	/* check if shm_destroy() is tearing down shp */
1602	if (!ipc_valid_object(perm: &shp->shm_perm)) {
1603	ipc_unlock_object(perm: &shp->shm_perm);
1604	err = -EIDRM;
1605	goto out_unlock;
1606	}
1607
1608	/*
1609	* We need to take a reference to the real shm file to prevent the
1610	* pointer from becoming stale in cases where the lifetime of the outer
1611	* file extends beyond that of the shm segment. It's not usually
1612	* possible, but it can happen during remap_file_pages() emulation as
1613	* that unmaps the memory, then does ->mmap() via file reference only.
1614	* We'll deny the ->mmap() if the shm segment was since removed, but to
1615	* detect shm ID reuse we need to compare the file pointers.
1616	*/
1617	base = get_file(f: shp->shm_file);
1618	shp->shm_nattch++;
1619	size = i_size_read(inode: file_inode(f: base));
1620	ipc_unlock_object(perm: &shp->shm_perm);
1621	rcu_read_unlock();
1622
1623	err = -ENOMEM;
1624	sfd = kzalloc(size: sizeof(*sfd), GFP_KERNEL);
1625	if (!sfd) {
1626	fput(base);
1627	goto out_nattch;
1628	}
1629
1630	file = alloc_file_clone(base, flags: f_flags,
1631	is_file_hugepages(base) ?
1632	&shm_file_operations_huge :
1633	&shm_file_operations);
1634	err = PTR_ERR(ptr: file);
1635	if (IS_ERR(ptr: file)) {
1636	kfree(objp: sfd);
1637	fput(base);
1638	goto out_nattch;
1639	}
1640
1641	sfd->id = shp->shm_perm.id;
1642	sfd->ns = get_ipc_ns(ns);
1643	sfd->file = base;
1644	sfd->vm_ops = NULL;
1645	file->private_data = sfd;
1646
1647	err = security_mmap_file(file, prot, flags);
1648	if (err)
1649	goto out_fput;
1650
1651	if (mmap_write_lock_killable(current->mm)) {
1652	err = -EINTR;
1653	goto out_fput;
1654	}
1655
1656	if (addr && !(shmflg & SHM_REMAP)) {
1657	err = -EINVAL;
1658	if (addr + size < addr)
1659	goto invalid;
1660
1661	if (find_vma_intersection(current->mm, start_addr: addr, end_addr: addr + size))
1662	goto invalid;
1663	}
1664
1665	addr = do_mmap(file, addr, len: size, prot, flags, pgoff: 0, populate: &populate, NULL);
1666	*raddr = addr;
1667	err = 0;
1668	if (IS_ERR_VALUE(addr))
1669	err = (long)addr;
1670	invalid:
1671	mmap_write_unlock(current->mm);
1672	if (populate)
1673	mm_populate(addr, len: populate);
1674
1675	out_fput:
1676	fput(file);
1677
1678	out_nattch:
1679	down_write(sem: &shm_ids(ns).rwsem);
1680	shp = shm_lock(ns, id: shmid);
1681	shp->shm_nattch--;
1682
1683	if (shm_may_destroy(shp))
1684	shm_destroy(ns, shp);
1685	else
1686	shm_unlock(shp);
1687	up_write(sem: &shm_ids(ns).rwsem);
1688	return err;
1689
1690	out_unlock:
1691	rcu_read_unlock();
1692	out:
1693	return err;
1694	}
1695
1696	SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
1697	{
1698	unsigned long ret;
1699	long err;
1700
1701	err = do_shmat(shmid, shmaddr, shmflg, &ret, SHMLBA);
1702	if (err)
1703	return err;
1704	force_successful_syscall_return();
1705	return (long)ret;
1706	}
1707
1708	#ifdef CONFIG_COMPAT
1709
1710	#ifndef COMPAT_SHMLBA
1711	#define COMPAT_SHMLBA SHMLBA
1712	#endif
1713
1714	COMPAT_SYSCALL_DEFINE3(shmat, int, shmid, compat_uptr_t, shmaddr, int, shmflg)
1715	{
1716	unsigned long ret;
1717	long err;
1718
1719	err = do_shmat(shmid, compat_ptr(shmaddr), shmflg, &ret, COMPAT_SHMLBA);
1720	if (err)
1721	return err;
1722	force_successful_syscall_return();
1723	return (long)ret;
1724	}
1725	#endif
1726
1727	/*
1728	* detach and kill segment if marked destroyed.
1729	* The work is done in shm_close.
1730	*/
1731	long ksys_shmdt(char __user *shmaddr)
1732	{
1733	struct mm_struct *mm = current->mm;
1734	struct vm_area_struct *vma;
1735	unsigned long addr = (unsigned long)shmaddr;
1736	int retval = -EINVAL;
1737	#ifdef CONFIG_MMU
1738	loff_t size = 0;
1739	struct file *file;
1740	VMA_ITERATOR(vmi, mm, addr);
1741	#endif
1742
1743	if (addr & ~PAGE_MASK)
1744	return retval;
1745
1746	if (mmap_write_lock_killable(mm))
1747	return -EINTR;
1748
1749	/*
1750	* This function tries to be smart and unmap shm segments that
1751	* were modified by partial mlock or munmap calls:
1752	* - It first determines the size of the shm segment that should be
1753	* unmapped: It searches for a vma that is backed by shm and that
1754	* started at address shmaddr. It records it's size and then unmaps
1755	* it.
1756	* - Then it unmaps all shm vmas that started at shmaddr and that
1757	* are within the initially determined size and that are from the
1758	* same shm segment from which we determined the size.
1759	* Errors from do_munmap are ignored: the function only fails if
1760	* it's called with invalid parameters or if it's called to unmap
1761	* a part of a vma. Both calls in this function are for full vmas,
1762	* the parameters are directly copied from the vma itself and always
1763	* valid - therefore do_munmap cannot fail. (famous last words?)
1764	*/
1765	/*
1766	* If it had been mremap()'d, the starting address would not
1767	* match the usual checks anyway. So assume all vma's are
1768	* above the starting address given.
1769	*/
1770
1771	#ifdef CONFIG_MMU
1772	for_each_vma(vmi, vma) {
1773	/*
1774	* Check if the starting address would match, i.e. it's
1775	* a fragment created by mprotect() and/or munmap(), or it
1776	* otherwise it starts at this address with no hassles.
1777	*/
1778	if ((vma->vm_ops == &shm_vm_ops) &&
1779	(vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1780
1781	/*
1782	* Record the file of the shm segment being
1783	* unmapped. With mremap(), someone could place
1784	* page from another segment but with equal offsets
1785	* in the range we are unmapping.
1786	*/
1787	file = vma->vm_file;
1788	size = i_size_read(file_inode(vma->vm_file));
1789	do_vma_munmap(&vmi, vma, vma->vm_start, vma->vm_end,
1790	NULL, false);
1791	/*
1792	* We discovered the size of the shm segment, so
1793	* break out of here and fall through to the next
1794	* loop that uses the size information to stop
1795	* searching for matching vma's.
1796	*/
1797	retval = 0;
1798	vma = vma_next(&vmi);
1799	break;
1800	}
1801	}
1802
1803	/*
1804	* We need look no further than the maximum address a fragment
1805	* could possibly have landed at. Also cast things to loff_t to
1806	* prevent overflows and make comparisons vs. equal-width types.
1807	*/
1808	size = PAGE_ALIGN(size);
1809	while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1810	/* finding a matching vma now does not alter retval */
1811	if ((vma->vm_ops == &shm_vm_ops) &&
1812	((vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) &&
1813	(vma->vm_file == file)) {
1814	do_vma_munmap(&vmi, vma, vma->vm_start, vma->vm_end,
1815	NULL, false);
1816	}
1817
1818	vma = vma_next(&vmi);
1819	}
1820
1821	#else /* CONFIG_MMU */
1822	vma = vma_lookup(mm, addr);
1823	/* under NOMMU conditions, the exact address to be destroyed must be
1824	* given
1825	*/
1826	if (vma && vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1827	do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start, NULL);
1828	retval = 0;
1829	}
1830
1831	#endif
1832
1833	mmap_write_unlock(mm);
1834	return retval;
1835	}
1836
1837	SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
1838	{
1839	return ksys_shmdt(shmaddr);
1840	}
1841
1842	#ifdef CONFIG_PROC_FS
1843	static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1844	{
1845	struct pid_namespace *pid_ns = ipc_seq_pid_ns(s);
1846	struct user_namespace *user_ns = seq_user_ns(s);
1847	struct kern_ipc_perm *ipcp = it;
1848	struct shmid_kernel *shp;
1849	unsigned long rss = 0, swp = 0;
1850
1851	shp = container_of(ipcp, struct shmid_kernel, shm_perm);
1852	shm_add_rss_swap(shp, &rss, &swp);
1853
1854	#if BITS_PER_LONG <= 32
1855	#define SIZE_SPEC "%10lu"
1856	#else
1857	#define SIZE_SPEC "%21lu"
1858	#endif
1859
1860	seq_printf(s,
1861	"%10d %10d %4o " SIZE_SPEC " %5u %5u "
1862	"%5lu %5u %5u %5u %5u %10llu %10llu %10llu "
1863	SIZE_SPEC " " SIZE_SPEC "\n",
1864	shp->shm_perm.key,
1865	shp->shm_perm.id,
1866	shp->shm_perm.mode,
1867	shp->shm_segsz,
1868	pid_nr_ns(shp->shm_cprid, pid_ns),
1869	pid_nr_ns(shp->shm_lprid, pid_ns),
1870	shp->shm_nattch,
1871	from_kuid_munged(user_ns, shp->shm_perm.uid),
1872	from_kgid_munged(user_ns, shp->shm_perm.gid),
1873	from_kuid_munged(user_ns, shp->shm_perm.cuid),
1874	from_kgid_munged(user_ns, shp->shm_perm.cgid),
1875	shp->shm_atim,
1876	shp->shm_dtim,
1877	shp->shm_ctim,
1878	rss * PAGE_SIZE,
1879	swp * PAGE_SIZE);
1880
1881	return 0;
1882	}
1883	#endif
1884