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 <uapi/linux/shm.h>
33	#include <linux/init.h>
34	#include <linux/file.h>
35	#include <linux/mman.h>
36	#include <linux/shmem_fs.h>
37	#include <linux/security.h>
38	#include <linux/syscalls.h>
39	#include <linux/audit.h>
40	#include <linux/capability.h>
41	#include <linux/ptrace.h>
42	#include <linux/seq_file.h>
43	#include <linux/rwsem.h>
44	#include <linux/nsproxy.h>
45	#include <linux/mount.h>
46	#include <linux/ipc_namespace.h>
47	#include <linux/rhashtable.h>
48
49	#include <linux/uaccess.h>
50
51	#include "util.h"
52
53	struct shmid_kernel /* private to the kernel */
54	{
55	struct kern_ipc_perm shm_perm;
56	struct file *shm_file;
57	unsigned long shm_nattch;
58	unsigned long shm_segsz;
59	time64_t shm_atim;
60	time64_t shm_dtim;
61	time64_t shm_ctim;
62	struct pid *shm_cprid;
63	struct pid *shm_lprid;
64	struct ucounts *mlock_ucounts;
65
66	/*
67	* The task created the shm object, for
68	* task_lock(shp->shm_creator)
69	*/
70	struct task_struct *shm_creator;
71
72	/*
73	* List by creator. task_lock(->shm_creator) required for read/write.
74	* If list_empty(), then the creator is dead already.
75	*/
76	struct list_head shm_clist;
77	struct ipc_namespace *ns;
78	} __randomize_layout;
79
80	/* shm_mode upper byte flags */
81	#define SHM_DEST 01000 /* segment will be destroyed on last detach */
82	#define SHM_LOCKED 02000 /* segment will not be swapped */
83
84	struct shm_file_data {
85	int id;
86	struct ipc_namespace *ns;
87	struct file *file;
88	const struct vm_operations_struct *vm_ops;
89	};
90
91	#define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
92
93	static const struct file_operations shm_file_operations;
94	static const struct vm_operations_struct shm_vm_ops;
95
96	#define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS])
97
98	#define shm_unlock(shp) \
99	ipc_unlock(&(shp)->shm_perm)
100
101	static int newseg(struct ipc_namespace *, struct ipc_params *);
102	static void shm_open(struct vm_area_struct *vma);
103	static void shm_close(struct vm_area_struct *vma);
104	static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp);
105	#ifdef CONFIG_PROC_FS
106	static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
107	#endif
108
109	void shm_init_ns(struct ipc_namespace *ns)
110	{
111	ns->shm_ctlmax = SHMMAX;
112	ns->shm_ctlall = SHMALL;
113	ns->shm_ctlmni = SHMMNI;
114	ns->shm_rmid_forced = 0;
115	ns->shm_tot = 0;
116	ipc_init_ids(ids: &shm_ids(ns));
117	}
118
119	/*
120	* Called with shm_ids.rwsem (writer) and the shp structure locked.
121	* Only shm_ids.rwsem remains locked on exit.
122	*/
123	static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
124	{
125	struct shmid_kernel *shp;
126
127	shp = container_of(ipcp, struct shmid_kernel, shm_perm);
128	WARN_ON(ns != shp->ns);
129
130	if (shp->shm_nattch) {
131	shp->shm_perm.mode |= SHM_DEST;
132	/* Do not find it any more */
133	ipc_set_key_private(&shm_ids(ns), &shp->shm_perm);
134	shm_unlock(shp);
135	} else
136	shm_destroy(ns, shp);
137	}
138
139	#ifdef CONFIG_IPC_NS
140	void shm_exit_ns(struct ipc_namespace *ns)
141	{
142	free_ipcs(ns, ids: &shm_ids(ns), free: do_shm_rmid);
143	idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
144	rhashtable_destroy(ht: &ns->ids[IPC_SHM_IDS].key_ht);
145	}
146	#endif
147
148	static int __init ipc_ns_init(void)
149	{
150	shm_init_ns(ns: &init_ipc_ns);
151	return 0;
152	}
153
154	pure_initcall(ipc_ns_init);
155
156	void __init shm_init(void)
157	{
158	ipc_init_proc_interface(path: "sysvipc/shm",
159	#if BITS_PER_LONG <= 32
160	" key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
161	#else
162	header: " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
163	#endif
164	IPC_SHM_IDS, show: sysvipc_shm_proc_show);
165	}
166
167	static inline struct shmid_kernel *shm_obtain_object(struct ipc_namespace *ns, int id)
168	{
169	struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(ids: &shm_ids(ns), id);
170
171	if (IS_ERR(ptr: ipcp))
172	return ERR_CAST(ptr: ipcp);
173
174	return container_of(ipcp, struct shmid_kernel, shm_perm);
175	}
176
177	static inline struct shmid_kernel *shm_obtain_object_check(struct ipc_namespace *ns, int id)
178	{
179	struct kern_ipc_perm *ipcp = ipc_obtain_object_check(ids: &shm_ids(ns), id);
180
181	if (IS_ERR(ptr: ipcp))
182	return ERR_CAST(ptr: ipcp);
183
184	return container_of(ipcp, struct shmid_kernel, shm_perm);
185	}
186
187	/*
188	* shm_lock_(check_) routines are called in the paths where the rwsem
189	* is not necessarily held.
190	*/
191	static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
192	{
193	struct kern_ipc_perm *ipcp;
194
195	rcu_read_lock();
196	ipcp = ipc_obtain_object_idr(ids: &shm_ids(ns), id);
197	if (IS_ERR(ptr: ipcp))
198	goto err;
199
200	ipc_lock_object(perm: ipcp);
201	/*
202	* ipc_rmid() may have already freed the ID while ipc_lock_object()
203	* was spinning: here verify that the structure is still valid.
204	* Upon races with RMID, return -EIDRM, thus indicating that
205	* the ID points to a removed identifier.
206	*/
207	if (ipc_valid_object(perm: ipcp)) {
208	/* return a locked ipc object upon success */
209	return container_of(ipcp, struct shmid_kernel, shm_perm);
210	}
211
212	ipc_unlock_object(perm: ipcp);
213	ipcp = ERR_PTR(error: -EIDRM);
214	err:
215	rcu_read_unlock();
216	/*
217	* Callers of shm_lock() must validate the status of the returned ipc
218	* object pointer and error out as appropriate.
219	*/
220	return ERR_CAST(ptr: ipcp);
221	}
222
223	static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
224	{
225	rcu_read_lock();
226	ipc_lock_object(perm: &ipcp->shm_perm);
227	}
228
229	static void shm_rcu_free(struct rcu_head *head)
230	{
231	struct kern_ipc_perm *ptr = container_of(head, struct kern_ipc_perm,
232	rcu);
233	struct shmid_kernel *shp = container_of(ptr, struct shmid_kernel,
234	shm_perm);
235	security_shm_free(shp: &shp->shm_perm);
236	kfree(objp: shp);
237	}
238
239	/*
240	* It has to be called with shp locked.
241	* It must be called before ipc_rmid()
242	*/
243	static inline void shm_clist_rm(struct shmid_kernel *shp)
244	{
245	struct task_struct *creator;
246
247	/* ensure that shm_creator does not disappear */
248	rcu_read_lock();
249
250	/*
251	* A concurrent exit_shm may do a list_del_init() as well.
252	* Just do nothing if exit_shm already did the work
253	*/
254	if (!list_empty(head: &shp->shm_clist)) {
255	/*
256	* shp->shm_creator is guaranteed to be valid *only*
257	* if shp->shm_clist is not empty.
258	*/
259	creator = shp->shm_creator;
260
261	task_lock(p: creator);
262	/*
263	* list_del_init() is a nop if the entry was already removed
264	* from the list.
265	*/
266	list_del_init(entry: &shp->shm_clist);
267	task_unlock(p: creator);
268	}
269	rcu_read_unlock();
270	}
271
272	static inline void shm_rmid(struct shmid_kernel *s)
273	{
274	shm_clist_rm(shp: s);
275	ipc_rmid(&shm_ids(s->ns), &s->shm_perm);
276	}
277
278
279	static int __shm_open(struct shm_file_data *sfd)
280	{
281	struct shmid_kernel *shp;
282
283	shp = shm_lock(ns: sfd->ns, id: sfd->id);
284
285	if (IS_ERR(ptr: shp))
286	return PTR_ERR(ptr: shp);
287
288	if (shp->shm_file != sfd->file) {
289	/* ID was reused */
290	shm_unlock(shp);
291	return -EINVAL;
292	}
293
294	shp->shm_atim = ktime_get_real_seconds();
295	ipc_update_pid(pos: &shp->shm_lprid, pid: task_tgid(current));
296	shp->shm_nattch++;
297	shm_unlock(shp);
298	return 0;
299	}
300
301	/* This is called by fork, once for every shm attach. */
302	static void shm_open(struct vm_area_struct *vma)
303	{
304	struct file *file = vma->vm_file;
305	struct shm_file_data *sfd = shm_file_data(file);
306	int err;
307
308	/* Always call underlying open if present */
309	if (sfd->vm_ops->open)
310	sfd->vm_ops->open(vma);
311
312	err = __shm_open(sfd);
313	/*
314	* We raced in the idr lookup or with shm_destroy().
315	* Either way, the ID is busted.
316	*/
317	WARN_ON_ONCE(err);
318	}
319
320	/*
321	* shm_destroy - free the struct shmid_kernel
322	*
323	* @ns: namespace
324	* @shp: struct to free
325	*
326	* It has to be called with shp and shm_ids.rwsem (writer) locked,
327	* but returns with shp unlocked and freed.
328	*/
329	static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
330	{
331	struct file *shm_file;
332
333	shm_file = shp->shm_file;
334	shp->shm_file = NULL;
335	ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
336	shm_rmid(s: shp);
337	shm_unlock(shp);
338	if (!is_file_hugepages(file: shm_file))
339	shmem_lock(file: shm_file, lock: 0, ucounts: shp->mlock_ucounts);
340	fput(shm_file);
341	ipc_update_pid(pos: &shp->shm_cprid, NULL);
342	ipc_update_pid(pos: &shp->shm_lprid, NULL);
343	ipc_rcu_putref(ptr: &shp->shm_perm, func: shm_rcu_free);
344	}
345
346	/*
347	* shm_may_destroy - identifies whether shm segment should be destroyed now
348	*
349	* Returns true if and only if there are no active users of the segment and
350	* one of the following is true:
351	*
352	* 1) shmctl(id, IPC_RMID, NULL) was called for this shp
353	*
354	* 2) sysctl kernel.shm_rmid_forced is set to 1.
355	*/
356	static bool shm_may_destroy(struct shmid_kernel *shp)
357	{
358	return (shp->shm_nattch == 0) &&
359	(shp->ns->shm_rmid_forced ||
360	(shp->shm_perm.mode & SHM_DEST));
361	}
362
363	/*
364	* remove the attach descriptor vma.
365	* free memory for segment if it is marked destroyed.
366	* The descriptor has already been removed from the current->mm->mmap list
367	* and will later be kfree()d.
368	*/
369	static void __shm_close(struct shm_file_data *sfd)
370	{
371	struct shmid_kernel *shp;
372	struct ipc_namespace *ns = sfd->ns;
373
374	down_write(sem: &shm_ids(ns).rwsem);
375	/* remove from the list of attaches of the shm segment */
376	shp = shm_lock(ns, id: sfd->id);
377
378	/*
379	* We raced in the idr lookup or with shm_destroy().
380	* Either way, the ID is busted.
381	*/
382	if (WARN_ON_ONCE(IS_ERR(shp)))
383	goto done; /* no-op */
384
385	ipc_update_pid(pos: &shp->shm_lprid, pid: task_tgid(current));
386	shp->shm_dtim = ktime_get_real_seconds();
387	shp->shm_nattch--;
388	if (shm_may_destroy(shp))
389	shm_destroy(ns, shp);
390	else
391	shm_unlock(shp);
392	done:
393	up_write(sem: &shm_ids(ns).rwsem);
394	}
395
396	static void shm_close(struct vm_area_struct *vma)
397	{
398	struct file *file = vma->vm_file;
399	struct shm_file_data *sfd = shm_file_data(file);
400
401	/* Always call underlying close if present */
402	if (sfd->vm_ops->close)
403	sfd->vm_ops->close(vma);
404
405	__shm_close(sfd);
406	}
407
408	/* Called with ns->shm_ids(ns).rwsem locked */
409	static int shm_try_destroy_orphaned(int id, void *p, void *data)
410	{
411	struct ipc_namespace *ns = data;
412	struct kern_ipc_perm *ipcp = p;
413	struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
414
415	/*
416	* We want to destroy segments without users and with already
417	* exit'ed originating process.
418	*
419	* As shp->* are changed under rwsem, it's safe to skip shp locking.
420	*/
421	if (!list_empty(head: &shp->shm_clist))
422	return 0;
423
424	if (shm_may_destroy(shp)) {
425	shm_lock_by_ptr(ipcp: shp);
426	shm_destroy(ns, shp);
427	}
428	return 0;
429	}
430
431	void shm_destroy_orphaned(struct ipc_namespace *ns)
432	{
433	down_write(sem: &shm_ids(ns).rwsem);
434	if (shm_ids(ns).in_use)
435	idr_for_each(&shm_ids(ns).ipcs_idr, fn: &shm_try_destroy_orphaned, data: ns);
436	up_write(sem: &shm_ids(ns).rwsem);
437	}
438
439	/* Locking assumes this will only be called with task == current */
440	void exit_shm(struct task_struct *task)
441	{
442	for (;;) {
443	struct shmid_kernel *shp;
444	struct ipc_namespace *ns;
445
446	task_lock(p: task);
447
448	if (list_empty(head: &task->sysvshm.shm_clist)) {
449	task_unlock(p: task);
450	break;
451	}
452
453	shp = list_first_entry(&task->sysvshm.shm_clist, struct shmid_kernel,
454	shm_clist);
455
456	/*
457	* 1) Get pointer to the ipc namespace. It is worth to say
458	* that this pointer is guaranteed to be valid because
459	* shp lifetime is always shorter than namespace lifetime
460	* in which shp lives.
461	* We taken task_lock it means that shp won't be freed.
462	*/
463	ns = shp->ns;
464
465	/*
466	* 2) If kernel.shm_rmid_forced is not set then only keep track of
467	* which shmids are orphaned, so that a later set of the sysctl
468	* can clean them up.
469	*/
470	if (!ns->shm_rmid_forced)
471	goto unlink_continue;
472
473	/*
474	* 3) get a reference to the namespace.
475	* The refcount could be already 0. If it is 0, then
476	* the shm objects will be free by free_ipc_work().
477	*/
478	ns = get_ipc_ns_not_zero(ns);
479	if (!ns) {
480	unlink_continue:
481	list_del_init(entry: &shp->shm_clist);
482	task_unlock(p: task);
483	continue;
484	}
485
486	/*
487	* 4) get a reference to shp.
488	* This cannot fail: shm_clist_rm() is called before
489	* ipc_rmid(), thus the refcount cannot be 0.
490	*/
491	WARN_ON(!ipc_rcu_getref(&shp->shm_perm));
492
493	/*
494	* 5) unlink the shm segment from the list of segments
495	* created by current.
496	* This must be done last. After unlinking,
497	* only the refcounts obtained above prevent IPC_RMID
498	* from destroying the segment or the namespace.
499	*/
500	list_del_init(entry: &shp->shm_clist);
501
502	task_unlock(p: task);
503
504	/*
505	* 6) we have all references
506	* Thus lock & if needed destroy shp.
507	*/
508	down_write(sem: &shm_ids(ns).rwsem);
509	shm_lock_by_ptr(ipcp: shp);
510	/*
511	* rcu_read_lock was implicitly taken in shm_lock_by_ptr, it's
512	* safe to call ipc_rcu_putref here
513	*/
514	ipc_rcu_putref(ptr: &shp->shm_perm, func: shm_rcu_free);
515
516	if (ipc_valid_object(perm: &shp->shm_perm)) {
517	if (shm_may_destroy(shp))
518	shm_destroy(ns, shp);
519	else
520	shm_unlock(shp);
521	} else {
522	/*
523	* Someone else deleted the shp from namespace
524	* idr/kht while we have waited.
525	* Just unlock and continue.
526	*/
527	shm_unlock(shp);
528	}
529
530	up_write(sem: &shm_ids(ns).rwsem);
531	put_ipc_ns(ns); /* paired with get_ipc_ns_not_zero */
532	}
533	}
534
535	static vm_fault_t shm_fault(struct vm_fault *vmf)
536	{
537	struct file *file = vmf->vma->vm_file;
538	struct shm_file_data *sfd = shm_file_data(file);
539
540	return sfd->vm_ops->fault(vmf);
541	}
542
543	static int shm_may_split(struct vm_area_struct *vma, unsigned long addr)
544	{
545	struct file *file = vma->vm_file;
546	struct shm_file_data *sfd = shm_file_data(file);
547
548	if (sfd->vm_ops->may_split)
549	return sfd->vm_ops->may_split(vma, addr);
550
551	return 0;
552	}
553
554	static unsigned long shm_pagesize(struct vm_area_struct *vma)
555	{
556	struct file *file = vma->vm_file;
557	struct shm_file_data *sfd = shm_file_data(file);
558
559	if (sfd->vm_ops->pagesize)
560	return sfd->vm_ops->pagesize(vma);
561
562	return PAGE_SIZE;
563	}
564
565	#ifdef CONFIG_NUMA
566	static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *mpol)
567	{
568	struct shm_file_data *sfd = shm_file_data(vma->vm_file);
569	int err = 0;
570
571	if (sfd->vm_ops->set_policy)
572	err = sfd->vm_ops->set_policy(vma, mpol);
573	return err;
574	}
575
576	static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
577	unsigned long addr, pgoff_t *ilx)
578	{
579	struct shm_file_data *sfd = shm_file_data(vma->vm_file);
580	struct mempolicy *mpol = vma->vm_policy;
581
582	if (sfd->vm_ops->get_policy)
583	mpol = sfd->vm_ops->get_policy(vma, addr, ilx);
584	return mpol;
585	}
586	#endif
587
588	static int shm_mmap(struct file *file, struct vm_area_struct *vma)
589	{
590	struct shm_file_data *sfd = shm_file_data(file);
591	int ret;
592
593	/*
594	* In case of remap_file_pages() emulation, the file can represent an
595	* IPC ID that was removed, and possibly even reused by another shm
596	* segment already. Propagate this case as an error to caller.
597	*/
598	ret = __shm_open(sfd);
599	if (ret)
600	return ret;
601
602	ret = call_mmap(file: sfd->file, vma);
603	if (ret) {
604	__shm_close(sfd);
605	return ret;
606	}
607	sfd->vm_ops = vma->vm_ops;
608	#ifdef CONFIG_MMU
609	WARN_ON(!sfd->vm_ops->fault);
610	#endif
611	vma->vm_ops = &shm_vm_ops;
612	return 0;
613	}
614
615	static int shm_release(struct inode *ino, struct file *file)
616	{
617	struct shm_file_data *sfd = shm_file_data(file);
618
619	put_ipc_ns(ns: sfd->ns);
620	fput(sfd->file);
621	shm_file_data(file) = NULL;
622	kfree(objp: sfd);
623	return 0;
624	}
625
626	static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
627	{
628	struct shm_file_data *sfd = shm_file_data(file);
629
630	if (!sfd->file->f_op->fsync)
631	return -EINVAL;
632	return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
633	}
634
635	static long shm_fallocate(struct file *file, int mode, loff_t offset,
636	loff_t len)
637	{
638	struct shm_file_data *sfd = shm_file_data(file);
639
640	if (!sfd->file->f_op->fallocate)
641	return -EOPNOTSUPP;
642	return sfd->file->f_op->fallocate(file, mode, offset, len);
643	}
644
645	static unsigned long shm_get_unmapped_area(struct file *file,
646	unsigned long addr, unsigned long len, unsigned long pgoff,
647	unsigned long flags)
648	{
649	struct shm_file_data *sfd = shm_file_data(file);
650
651	return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
652	pgoff, flags);
653	}
654
655	static const struct file_operations shm_file_operations = {
656	.mmap = shm_mmap,
657	.fsync = shm_fsync,
658	.release = shm_release,
659	.get_unmapped_area = shm_get_unmapped_area,
660	.llseek = noop_llseek,
661	.fallocate = shm_fallocate,
662	};
663
664	/*
665	* shm_file_operations_huge is now identical to shm_file_operations,
666	* but we keep it distinct for the sake of is_file_shm_hugepages().
667	*/
668	static const struct file_operations shm_file_operations_huge = {
669	.mmap = shm_mmap,
670	.fsync = shm_fsync,
671	.release = shm_release,
672	.get_unmapped_area = shm_get_unmapped_area,
673	.llseek = noop_llseek,
674	.fallocate = shm_fallocate,
675	};
676
677	bool is_file_shm_hugepages(struct file *file)
678	{
679	return file->f_op == &shm_file_operations_huge;
680	}
681
682	static const struct vm_operations_struct shm_vm_ops = {
683	.open = shm_open, /* callback for a new vm-area open */
684	.close = shm_close, /* callback for when the vm-area is released */
685	.fault = shm_fault,
686	.may_split = shm_may_split,
687	.pagesize = shm_pagesize,
688	#if defined(CONFIG_NUMA)
689	.set_policy = shm_set_policy,
690	.get_policy = shm_get_policy,
691	#endif
692	};
693
694	/**
695	* newseg - Create a new shared memory segment
696	* @ns: namespace
697	* @params: ptr to the structure that contains key, size and shmflg
698	*
699	* Called with shm_ids.rwsem held as a writer.
700	*/
701	static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
702	{
703	key_t key = params->key;
704	int shmflg = params->flg;
705	size_t size = params->u.size;
706	int error;
707	struct shmid_kernel *shp;
708	size_t numpages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
709	struct file *file;
710	char name[13];
711	vm_flags_t acctflag = 0;
712
713	if (size < SHMMIN || size > ns->shm_ctlmax)
714	return -EINVAL;
715
716	if (numpages << PAGE_SHIFT < size)
717	return -ENOSPC;
718
719	if (ns->shm_tot + numpages < ns->shm_tot ||
720	ns->shm_tot + numpages > ns->shm_ctlall)
721	return -ENOSPC;
722
723	shp = kmalloc(size: sizeof(*shp), GFP_KERNEL_ACCOUNT);
724	if (unlikely(!shp))
725	return -ENOMEM;
726
727	shp->shm_perm.key = key;
728	shp->shm_perm.mode = (shmflg & S_IRWXUGO);
729	shp->mlock_ucounts = NULL;
730
731	shp->shm_perm.security = NULL;
732	error = security_shm_alloc(shp: &shp->shm_perm);
733	if (error) {
734	kfree(objp: shp);
735	return error;
736	}
737
738	sprintf(buf: name, fmt: "SYSV%08x", key);
739	if (shmflg & SHM_HUGETLB) {
740	struct hstate *hs;
741	size_t hugesize;
742
743	hs = hstate_sizelog(page_size_log: (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
744	if (!hs) {
745	error = -EINVAL;
746	goto no_file;
747	}
748	hugesize = ALIGN(size, huge_page_size(hs));
749
750	/* hugetlb_file_setup applies strict accounting */
751	if (shmflg & SHM_NORESERVE)
752	acctflag = VM_NORESERVE;
753	file = hugetlb_file_setup(name, size: hugesize, acct: acctflag,
754	creat_flags: HUGETLB_SHMFS_INODE, page_size_log: (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
755	} else {
756	/*
757	* Do not allow no accounting for OVERCOMMIT_NEVER, even
758	* if it's asked for.
759	*/
760	if ((shmflg & SHM_NORESERVE) &&
761	sysctl_overcommit_memory != OVERCOMMIT_NEVER)
762	acctflag = VM_NORESERVE;
763	file = shmem_kernel_file_setup(name, size, flags: acctflag);
764	}
765	error = PTR_ERR(ptr: file);
766	if (IS_ERR(ptr: file))
767	goto no_file;
768
769	shp->shm_cprid = get_pid(pid: task_tgid(current));
770	shp->shm_lprid = NULL;
771	shp->shm_atim = shp->shm_dtim = 0;
772	shp->shm_ctim = ktime_get_real_seconds();
773	shp->shm_segsz = size;
774	shp->shm_nattch = 0;
775	shp->shm_file = file;
776	shp->shm_creator = current;
777
778	/* ipc_addid() locks shp upon success. */
779	error = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
780	if (error < 0)
781	goto no_id;
782
783	shp->ns = ns;
784
785	task_lock(current);
786	list_add(new: &shp->shm_clist, head: &current->sysvshm.shm_clist);
787	task_unlock(current);
788
789	/*
790	* shmid gets reported as "inode#" in /proc/pid/maps.
791	* proc-ps tools use this. Changing this will break them.
792	*/
793	file_inode(f: file)->i_ino = shp->shm_perm.id;
794
795	ns->shm_tot += numpages;
796	error = shp->shm_perm.id;
797
798	ipc_unlock_object(perm: &shp->shm_perm);
799	rcu_read_unlock();
800	return error;
801
802	no_id:
803	ipc_update_pid(pos: &shp->shm_cprid, NULL);
804	ipc_update_pid(pos: &shp->shm_lprid, NULL);
805	fput(file);
806	ipc_rcu_putref(ptr: &shp->shm_perm, func: shm_rcu_free);
807	return error;
808	no_file:
809	call_rcu(head: &shp->shm_perm.rcu, func: shm_rcu_free);
810	return error;
811	}
812
813	/*
814	* Called with shm_ids.rwsem and ipcp locked.
815	*/
816	static int shm_more_checks(struct kern_ipc_perm *ipcp, struct ipc_params *params)
817	{
818	struct shmid_kernel *shp;
819
820	shp = container_of(ipcp, struct shmid_kernel, shm_perm);
821	if (shp->shm_segsz < params->u.size)
822	return -EINVAL;
823
824	return 0;
825	}
826
827	long ksys_shmget(key_t key, size_t size, int shmflg)
828	{
829	struct ipc_namespace *ns;
830	static const struct ipc_ops shm_ops = {
831	.getnew = newseg,
832	.associate = security_shm_associate,
833	.more_checks = shm_more_checks,
834	};
835	struct ipc_params shm_params;
836
837	ns = current->nsproxy->ipc_ns;
838
839	shm_params.key = key;
840	shm_params.flg = shmflg;
841	shm_params.u.size = size;
842
843	return ipcget(ns, ids: &shm_ids(ns), ops: &shm_ops, params: &shm_params);
844	}
845
846	SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
847	{
848	return ksys_shmget(key, size, shmflg);
849	}
850
851	static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
852	{
853	switch (version) {
854	case IPC_64:
855	return copy_to_user(to: buf, from: in, n: sizeof(*in));
856	case IPC_OLD:
857	{
858	struct shmid_ds out;
859
860	memset(&out, 0, sizeof(out));
861	ipc64_perm_to_ipc_perm(in: &in->shm_perm, out: &out.shm_perm);
862	out.shm_segsz = in->shm_segsz;
863	out.shm_atime = in->shm_atime;
864	out.shm_dtime = in->shm_dtime;
865	out.shm_ctime = in->shm_ctime;
866	out.shm_cpid = in->shm_cpid;
867	out.shm_lpid = in->shm_lpid;
868	out.shm_nattch = in->shm_nattch;
869
870	return copy_to_user(to: buf, from: &out, n: sizeof(out));
871	}
872	default:
873	return -EINVAL;
874	}
875	}
876
877	static inline unsigned long
878	copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
879	{
880	switch (version) {
881	case IPC_64:
882	if (copy_from_user(to: out, from: buf, n: sizeof(*out)))
883	return -EFAULT;
884	return 0;
885	case IPC_OLD:
886	{
887	struct shmid_ds tbuf_old;
888
889	if (copy_from_user(to: &tbuf_old, from: buf, n: sizeof(tbuf_old)))
890	return -EFAULT;
891
892	out->shm_perm.uid = tbuf_old.shm_perm.uid;
893	out->shm_perm.gid = tbuf_old.shm_perm.gid;
894	out->shm_perm.mode = tbuf_old.shm_perm.mode;
895
896	return 0;
897	}
898	default:
899	return -EINVAL;
900	}
901	}
902
903	static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
904	{
905	switch (version) {
906	case IPC_64:
907	return copy_to_user(to: buf, from: in, n: sizeof(*in));
908	case IPC_OLD:
909	{
910	struct shminfo out;
911
912	if (in->shmmax > INT_MAX)
913	out.shmmax = INT_MAX;
914	else
915	out.shmmax = (int)in->shmmax;
916
917	out.shmmin = in->shmmin;
918	out.shmmni = in->shmmni;
919	out.shmseg = in->shmseg;
920	out.shmall = in->shmall;
921
922	return copy_to_user(to: buf, from: &out, n: sizeof(out));
923	}
924	default:
925	return -EINVAL;
926	}
927	}
928
929	/*
930	* Calculate and add used RSS and swap pages of a shm.
931	* Called with shm_ids.rwsem held as a reader
932	*/
933	static void shm_add_rss_swap(struct shmid_kernel *shp,
934	unsigned long *rss_add, unsigned long *swp_add)
935	{
936	struct inode *inode;
937
938	inode = file_inode(f: shp->shm_file);
939
940	if (is_file_hugepages(file: shp->shm_file)) {
941	struct address_space *mapping = inode->i_mapping;
942	struct hstate *h = hstate_file(f: shp->shm_file);
943	*rss_add += pages_per_huge_page(h) * mapping->nrpages;
944	} else {
945	#ifdef CONFIG_SHMEM
946	struct shmem_inode_info *info = SHMEM_I(inode);
947
948	spin_lock_irq(lock: &info->lock);
949	*rss_add += inode->i_mapping->nrpages;
950	*swp_add += info->swapped;
951	spin_unlock_irq(lock: &info->lock);
952	#else
953	*rss_add += inode->i_mapping->nrpages;
954	#endif
955	}
956	}
957
958	/*
959	* Called with shm_ids.rwsem held as a reader
960	*/
961	static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
962	unsigned long *swp)
963	{
964	int next_id;
965	int total, in_use;
966
967	*rss = 0;
968	*swp = 0;
969
970	in_use = shm_ids(ns).in_use;
971
972	for (total = 0, next_id = 0; total < in_use; next_id++) {
973	struct kern_ipc_perm *ipc;
974	struct shmid_kernel *shp;
975
976	ipc = idr_find(&shm_ids(ns).ipcs_idr, id: next_id);
977	if (ipc == NULL)
978	continue;
979	shp = container_of(ipc, struct shmid_kernel, shm_perm);
980
981	shm_add_rss_swap(shp, rss_add: rss, swp_add: swp);
982
983	total++;
984	}
985	}
986
987	/*
988	* This function handles some shmctl commands which require the rwsem
989	* to be held in write mode.
990	* NOTE: no locks must be held, the rwsem is taken inside this function.
991	*/
992	static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
993	struct shmid64_ds *shmid64)
994	{
995	struct kern_ipc_perm *ipcp;
996	struct shmid_kernel *shp;
997	int err;
998
999	down_write(sem: &shm_ids(ns).rwsem);
1000	rcu_read_lock();
1001
1002	ipcp = ipcctl_obtain_check(ns, ids: &shm_ids(ns), id: shmid, cmd,
1003	perm: &shmid64->shm_perm, extra_perm: 0);
1004	if (IS_ERR(ptr: ipcp)) {
1005	err = PTR_ERR(ptr: ipcp);
1006	goto out_unlock1;
1007	}
1008
1009	shp = container_of(ipcp, struct shmid_kernel, shm_perm);
1010
1011	err = security_shm_shmctl(shp: &shp->shm_perm, cmd);
1012	if (err)
1013	goto out_unlock1;
1014
1015	switch (cmd) {
1016	case IPC_RMID:
1017	ipc_lock_object(perm: &shp->shm_perm);
1018	/* do_shm_rmid unlocks the ipc object and rcu */
1019	do_shm_rmid(ns, ipcp);
1020	goto out_up;
1021	case IPC_SET:
1022	ipc_lock_object(perm: &shp->shm_perm);
1023	err = ipc_update_perm(in: &shmid64->shm_perm, out: ipcp);
1024	if (err)
1025	goto out_unlock0;
1026	shp->shm_ctim = ktime_get_real_seconds();
1027	break;
1028	default:
1029	err = -EINVAL;
1030	goto out_unlock1;
1031	}
1032
1033	out_unlock0:
1034	ipc_unlock_object(perm: &shp->shm_perm);
1035	out_unlock1:
1036	rcu_read_unlock();
1037	out_up:
1038	up_write(sem: &shm_ids(ns).rwsem);
1039	return err;
1040	}
1041
1042	static int shmctl_ipc_info(struct ipc_namespace *ns,
1043	struct shminfo64 *shminfo)
1044	{
1045	int err = security_shm_shmctl(NULL, IPC_INFO);
1046	if (!err) {
1047	memset(shminfo, 0, sizeof(*shminfo));
1048	shminfo->shmmni = shminfo->shmseg = ns->shm_ctlmni;
1049	shminfo->shmmax = ns->shm_ctlmax;
1050	shminfo->shmall = ns->shm_ctlall;
1051	shminfo->shmmin = SHMMIN;
1052	down_read(sem: &shm_ids(ns).rwsem);
1053	err = ipc_get_maxidx(ids: &shm_ids(ns));
1054	up_read(sem: &shm_ids(ns).rwsem);
1055	if (err < 0)
1056	err = 0;
1057	}
1058	return err;
1059	}
1060
1061	static int shmctl_shm_info(struct ipc_namespace *ns,
1062	struct shm_info *shm_info)
1063	{
1064	int err = security_shm_shmctl(NULL, SHM_INFO);
1065	if (!err) {
1066	memset(shm_info, 0, sizeof(*shm_info));
1067	down_read(sem: &shm_ids(ns).rwsem);
1068	shm_info->used_ids = shm_ids(ns).in_use;
1069	shm_get_stat(ns, rss: &shm_info->shm_rss, swp: &shm_info->shm_swp);
1070	shm_info->shm_tot = ns->shm_tot;
1071	shm_info->swap_attempts = 0;
1072	shm_info->swap_successes = 0;
1073	err = ipc_get_maxidx(ids: &shm_ids(ns));
1074	up_read(sem: &shm_ids(ns).rwsem);
1075	if (err < 0)
1076	err = 0;
1077	}
1078	return err;
1079	}
1080
1081	static int shmctl_stat(struct ipc_namespace *ns, int shmid,
1082	int cmd, struct shmid64_ds *tbuf)
1083	{
1084	struct shmid_kernel *shp;
1085	int err;
1086
1087	memset(tbuf, 0, sizeof(*tbuf));
1088
1089	rcu_read_lock();
1090	if (cmd == SHM_STAT || cmd == SHM_STAT_ANY) {
1091	shp = shm_obtain_object(ns, id: shmid);
1092	if (IS_ERR(ptr: shp)) {
1093	err = PTR_ERR(ptr: shp);
1094	goto out_unlock;
1095	}
1096	} else { /* IPC_STAT */
1097	shp = shm_obtain_object_check(ns, id: shmid);
1098	if (IS_ERR(ptr: shp)) {
1099	err = PTR_ERR(ptr: shp);
1100	goto out_unlock;
1101	}
1102	}
1103
1104	/*
1105	* Semantically SHM_STAT_ANY ought to be identical to
1106	* that functionality provided by the /proc/sysvipc/
1107	* interface. As such, only audit these calls and
1108	* do not do traditional S_IRUGO permission checks on
1109	* the ipc object.
1110	*/
1111	if (cmd == SHM_STAT_ANY)
1112	audit_ipc_obj(ipcp: &shp->shm_perm);
1113	else {
1114	err = -EACCES;
1115	if (ipcperms(ns, ipcp: &shp->shm_perm, S_IRUGO))
1116	goto out_unlock;
1117	}
1118
1119	err = security_shm_shmctl(shp: &shp->shm_perm, cmd);
1120	if (err)
1121	goto out_unlock;
1122
1123	ipc_lock_object(perm: &shp->shm_perm);
1124
1125	if (!ipc_valid_object(perm: &shp->shm_perm)) {
1126	ipc_unlock_object(perm: &shp->shm_perm);
1127	err = -EIDRM;
1128	goto out_unlock;
1129	}
1130
1131	kernel_to_ipc64_perm(in: &shp->shm_perm, out: &tbuf->shm_perm);
1132	tbuf->shm_segsz = shp->shm_segsz;
1133	tbuf->shm_atime = shp->shm_atim;
1134	tbuf->shm_dtime = shp->shm_dtim;
1135	tbuf->shm_ctime = shp->shm_ctim;
1136	#ifndef CONFIG_64BIT
1137	tbuf->shm_atime_high = shp->shm_atim >> 32;
1138	tbuf->shm_dtime_high = shp->shm_dtim >> 32;
1139	tbuf->shm_ctime_high = shp->shm_ctim >> 32;
1140	#endif
1141	tbuf->shm_cpid = pid_vnr(pid: shp->shm_cprid);
1142	tbuf->shm_lpid = pid_vnr(pid: shp->shm_lprid);
1143	tbuf->shm_nattch = shp->shm_nattch;
1144
1145	if (cmd == IPC_STAT) {
1146	/*
1147	* As defined in SUS:
1148	* Return 0 on success
1149	*/
1150	err = 0;
1151	} else {
1152	/*
1153	* SHM_STAT and SHM_STAT_ANY (both Linux specific)
1154	* Return the full id, including the sequence number
1155	*/
1156	err = shp->shm_perm.id;
1157	}
1158
1159	ipc_unlock_object(perm: &shp->shm_perm);
1160	out_unlock:
1161	rcu_read_unlock();
1162	return err;
1163	}
1164
1165	static int shmctl_do_lock(struct ipc_namespace *ns, int shmid, int cmd)
1166	{
1167	struct shmid_kernel *shp;
1168	struct file *shm_file;
1169	int err;
1170
1171	rcu_read_lock();
1172	shp = shm_obtain_object_check(ns, id: shmid);
1173	if (IS_ERR(ptr: shp)) {
1174	err = PTR_ERR(ptr: shp);
1175	goto out_unlock1;
1176	}
1177
1178	audit_ipc_obj(ipcp: &(shp->shm_perm));
1179	err = security_shm_shmctl(shp: &shp->shm_perm, cmd);
1180	if (err)
1181	goto out_unlock1;
1182
1183	ipc_lock_object(perm: &shp->shm_perm);
1184
1185	/* check if shm_destroy() is tearing down shp */
1186	if (!ipc_valid_object(perm: &shp->shm_perm)) {
1187	err = -EIDRM;
1188	goto out_unlock0;
1189	}
1190
1191	if (!ns_capable(ns: ns->user_ns, CAP_IPC_LOCK)) {
1192	kuid_t euid = current_euid();
1193
1194	if (!uid_eq(left: euid, right: shp->shm_perm.uid) &&
1195	!uid_eq(left: euid, right: shp->shm_perm.cuid)) {
1196	err = -EPERM;
1197	goto out_unlock0;
1198	}
1199	if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) {
1200	err = -EPERM;
1201	goto out_unlock0;
1202	}
1203	}
1204
1205	shm_file = shp->shm_file;
1206	if (is_file_hugepages(file: shm_file))
1207	goto out_unlock0;
1208
1209	if (cmd == SHM_LOCK) {
1210	struct ucounts *ucounts = current_ucounts();
1211
1212	err = shmem_lock(file: shm_file, lock: 1, ucounts);
1213	if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
1214	shp->shm_perm.mode |= SHM_LOCKED;
1215	shp->mlock_ucounts = ucounts;
1216	}
1217	goto out_unlock0;
1218	}
1219
1220	/* SHM_UNLOCK */
1221	if (!(shp->shm_perm.mode & SHM_LOCKED))
1222	goto out_unlock0;
1223	shmem_lock(file: shm_file, lock: 0, ucounts: shp->mlock_ucounts);
1224	shp->shm_perm.mode &= ~SHM_LOCKED;
1225	shp->mlock_ucounts = NULL;
1226	get_file(f: shm_file);
1227	ipc_unlock_object(perm: &shp->shm_perm);
1228	rcu_read_unlock();
1229	shmem_unlock_mapping(mapping: shm_file->f_mapping);
1230
1231	fput(shm_file);
1232	return err;
1233
1234	out_unlock0:
1235	ipc_unlock_object(perm: &shp->shm_perm);
1236	out_unlock1:
1237	rcu_read_unlock();
1238	return err;
1239	}
1240
1241	static long ksys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf, int version)
1242	{
1243	int err;
1244	struct ipc_namespace *ns;
1245	struct shmid64_ds sem64;
1246
1247	if (cmd < 0 || shmid < 0)
1248	return -EINVAL;
1249
1250	ns = current->nsproxy->ipc_ns;
1251
1252	switch (cmd) {
1253	case IPC_INFO: {
1254	struct shminfo64 shminfo;
1255	err = shmctl_ipc_info(ns, shminfo: &shminfo);
1256	if (err < 0)
1257	return err;
1258	if (copy_shminfo_to_user(buf, in: &shminfo, version))
1259	err = -EFAULT;
1260	return err;
1261	}
1262	case SHM_INFO: {
1263	struct shm_info shm_info;
1264	err = shmctl_shm_info(ns, shm_info: &shm_info);
1265	if (err < 0)
1266	return err;
1267	if (copy_to_user(to: buf, from: &shm_info, n: sizeof(shm_info)))
1268	err = -EFAULT;
1269	return err;
1270	}
1271	case SHM_STAT:
1272	case SHM_STAT_ANY:
1273	case IPC_STAT: {
1274	err = shmctl_stat(ns, shmid, cmd, tbuf: &sem64);
1275	if (err < 0)
1276	return err;
1277	if (copy_shmid_to_user(buf, in: &sem64, version))
1278	err = -EFAULT;
1279	return err;
1280	}
1281	case IPC_SET:
1282	if (copy_shmid_from_user(out: &sem64, buf, version))
1283	return -EFAULT;
1284	fallthrough;
1285	case IPC_RMID:
1286	return shmctl_down(ns, shmid, cmd, shmid64: &sem64);
1287	case SHM_LOCK:
1288	case SHM_UNLOCK:
1289	return shmctl_do_lock(ns, shmid, cmd);
1290	default:
1291	return -EINVAL;
1292	}
1293	}
1294
1295	SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
1296	{
1297	return ksys_shmctl(shmid, cmd, buf, IPC_64);
1298	}
1299
1300	#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
1301	long ksys_old_shmctl(int shmid, int cmd, struct shmid_ds __user *buf)
1302	{
1303	int version = ipc_parse_version(&cmd);
1304
1305	return ksys_shmctl(shmid, cmd, buf, version);
1306	}
1307
1308	SYSCALL_DEFINE3(old_shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
1309	{
1310	return ksys_old_shmctl(shmid, cmd, buf);
1311	}
1312	#endif
1313
1314	#ifdef CONFIG_COMPAT
1315
1316	struct compat_shmid_ds {
1317	struct compat_ipc_perm shm_perm;
1318	int shm_segsz;
1319	old_time32_t shm_atime;
1320	old_time32_t shm_dtime;
1321	old_time32_t shm_ctime;
1322	compat_ipc_pid_t shm_cpid;
1323	compat_ipc_pid_t shm_lpid;
1324	unsigned short shm_nattch;
1325	unsigned short shm_unused;
1326	compat_uptr_t shm_unused2;
1327	compat_uptr_t shm_unused3;
1328	};
1329
1330	struct compat_shminfo64 {
1331	compat_ulong_t shmmax;
1332	compat_ulong_t shmmin;
1333	compat_ulong_t shmmni;
1334	compat_ulong_t shmseg;
1335	compat_ulong_t shmall;
1336	compat_ulong_t __unused1;
1337	compat_ulong_t __unused2;
1338	compat_ulong_t __unused3;
1339	compat_ulong_t __unused4;
1340	};
1341
1342	struct compat_shm_info {
1343	compat_int_t used_ids;
1344	compat_ulong_t shm_tot, shm_rss, shm_swp;
1345	compat_ulong_t swap_attempts, swap_successes;
1346	};
1347
1348	static int copy_compat_shminfo_to_user(void __user *buf, struct shminfo64 *in,
1349	int version)
1350	{
1351	if (in->shmmax > INT_MAX)
1352	in->shmmax = INT_MAX;
1353	if (version == IPC_64) {
1354	struct compat_shminfo64 info;
1355	memset(&info, 0, sizeof(info));
1356	info.shmmax = in->shmmax;
1357	info.shmmin = in->shmmin;
1358	info.shmmni = in->shmmni;
1359	info.shmseg = in->shmseg;
1360	info.shmall = in->shmall;
1361	return copy_to_user(to: buf, from: &info, n: sizeof(info));
1362	} else {
1363	struct shminfo info;
1364	memset(&info, 0, sizeof(info));
1365	info.shmmax = in->shmmax;
1366	info.shmmin = in->shmmin;
1367	info.shmmni = in->shmmni;
1368	info.shmseg = in->shmseg;
1369	info.shmall = in->shmall;
1370	return copy_to_user(to: buf, from: &info, n: sizeof(info));
1371	}
1372	}
1373
1374	static int put_compat_shm_info(struct shm_info *ip,
1375	struct compat_shm_info __user *uip)
1376	{
1377	struct compat_shm_info info;
1378
1379	memset(&info, 0, sizeof(info));
1380	info.used_ids = ip->used_ids;
1381	info.shm_tot = ip->shm_tot;
1382	info.shm_rss = ip->shm_rss;
1383	info.shm_swp = ip->shm_swp;
1384	info.swap_attempts = ip->swap_attempts;
1385	info.swap_successes = ip->swap_successes;
1386	return copy_to_user(to: uip, from: &info, n: sizeof(info));
1387	}
1388
1389	static int copy_compat_shmid_to_user(void __user *buf, struct shmid64_ds *in,
1390	int version)
1391	{
1392	if (version == IPC_64) {
1393	struct compat_shmid64_ds v;
1394	memset(&v, 0, sizeof(v));
1395	to_compat_ipc64_perm(&v.shm_perm, &in->shm_perm);
1396	v.shm_atime = lower_32_bits(in->shm_atime);
1397	v.shm_atime_high = upper_32_bits(in->shm_atime);
1398	v.shm_dtime = lower_32_bits(in->shm_dtime);
1399	v.shm_dtime_high = upper_32_bits(in->shm_dtime);
1400	v.shm_ctime = lower_32_bits(in->shm_ctime);
1401	v.shm_ctime_high = upper_32_bits(in->shm_ctime);
1402	v.shm_segsz = in->shm_segsz;
1403	v.shm_nattch = in->shm_nattch;
1404	v.shm_cpid = in->shm_cpid;
1405	v.shm_lpid = in->shm_lpid;
1406	return copy_to_user(to: buf, from: &v, n: sizeof(v));
1407	} else {
1408	struct compat_shmid_ds v;
1409	memset(&v, 0, sizeof(v));
1410	to_compat_ipc_perm(&v.shm_perm, &in->shm_perm);
1411	v.shm_perm.key = in->shm_perm.key;
1412	v.shm_atime = in->shm_atime;
1413	v.shm_dtime = in->shm_dtime;
1414	v.shm_ctime = in->shm_ctime;
1415	v.shm_segsz = in->shm_segsz;
1416	v.shm_nattch = in->shm_nattch;
1417	v.shm_cpid = in->shm_cpid;
1418	v.shm_lpid = in->shm_lpid;
1419	return copy_to_user(to: buf, from: &v, n: sizeof(v));
1420	}
1421	}
1422
1423	static int copy_compat_shmid_from_user(struct shmid64_ds *out, void __user *buf,
1424	int version)
1425	{
1426	memset(out, 0, sizeof(*out));
1427	if (version == IPC_64) {
1428	struct compat_shmid64_ds __user *p = buf;
1429	return get_compat_ipc64_perm(&out->shm_perm, &p->shm_perm);
1430	} else {
1431	struct compat_shmid_ds __user *p = buf;
1432	return get_compat_ipc_perm(&out->shm_perm, &p->shm_perm);
1433	}
1434	}
1435
1436	static long compat_ksys_shmctl(int shmid, int cmd, void __user *uptr, int version)
1437	{
1438	struct ipc_namespace *ns;
1439	struct shmid64_ds sem64;
1440	int err;
1441
1442	ns = current->nsproxy->ipc_ns;
1443
1444	if (cmd < 0 || shmid < 0)
1445	return -EINVAL;
1446
1447	switch (cmd) {
1448	case IPC_INFO: {
1449	struct shminfo64 shminfo;
1450	err = shmctl_ipc_info(ns, shminfo: &shminfo);
1451	if (err < 0)
1452	return err;
1453	if (copy_compat_shminfo_to_user(buf: uptr, in: &shminfo, version))
1454	err = -EFAULT;
1455	return err;
1456	}
1457	case SHM_INFO: {
1458	struct shm_info shm_info;
1459	err = shmctl_shm_info(ns, shm_info: &shm_info);
1460	if (err < 0)
1461	return err;
1462	if (put_compat_shm_info(ip: &shm_info, uip: uptr))
1463	err = -EFAULT;
1464	return err;
1465	}
1466	case IPC_STAT:
1467	case SHM_STAT_ANY:
1468	case SHM_STAT:
1469	err = shmctl_stat(ns, shmid, cmd, tbuf: &sem64);
1470	if (err < 0)
1471	return err;
1472	if (copy_compat_shmid_to_user(buf: uptr, in: &sem64, version))
1473	err = -EFAULT;
1474	return err;
1475
1476	case IPC_SET:
1477	if (copy_compat_shmid_from_user(out: &sem64, buf: uptr, version))
1478	return -EFAULT;
1479	fallthrough;
1480	case IPC_RMID:
1481	return shmctl_down(ns, shmid, cmd, shmid64: &sem64);
1482	case SHM_LOCK:
1483	case SHM_UNLOCK:
1484	return shmctl_do_lock(ns, shmid, cmd);
1485	default:
1486	return -EINVAL;
1487	}
1488	return err;
1489	}
1490
1491	COMPAT_SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, void __user *, uptr)
1492	{
1493	return compat_ksys_shmctl(shmid, cmd, uptr, IPC_64);
1494	}
1495
1496	#ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION
1497	long compat_ksys_old_shmctl(int shmid, int cmd, void __user *uptr)
1498	{
1499	int version = compat_ipc_parse_version(cmd: &cmd);
1500
1501	return compat_ksys_shmctl(shmid, cmd, uptr, version);
1502	}
1503
1504	COMPAT_SYSCALL_DEFINE3(old_shmctl, int, shmid, int, cmd, void __user *, uptr)
1505	{
1506	return compat_ksys_old_shmctl(shmid, cmd, uptr);
1507	}
1508	#endif
1509	#endif
1510
1511	/*
1512	* Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
1513	*
1514	* NOTE! Despite the name, this is NOT a direct system call entrypoint. The
1515	* "raddr" thing points to kernel space, and there has to be a wrapper around
1516	* this.
1517	*/
1518	long do_shmat(int shmid, char __user *shmaddr, int shmflg,
1519	ulong *raddr, unsigned long shmlba)
1520	{
1521	struct shmid_kernel *shp;
1522	unsigned long addr = (unsigned long)shmaddr;
1523	unsigned long size;
1524	struct file *file, *base;
1525	int err;
1526	unsigned long flags = MAP_SHARED;
1527	unsigned long prot;
1528	int acc_mode;
1529	struct ipc_namespace *ns;
1530	struct shm_file_data *sfd;
1531	int f_flags;
1532	unsigned long populate = 0;
1533
1534	err = -EINVAL;
1535	if (shmid < 0)
1536	goto out;
1537
1538	if (addr) {
1539	if (addr & (shmlba - 1)) {
1540	if (shmflg & SHM_RND) {
1541	addr &= ~(shmlba - 1); /* round down */
1542
1543	/*
1544	* Ensure that the round-down is non-nil
1545	* when remapping. This can happen for
1546	* cases when addr < shmlba.
1547	*/
1548	if (!addr && (shmflg & SHM_REMAP))
1549	goto out;
1550	} else
1551	#ifndef __ARCH_FORCE_SHMLBA
1552	if (addr & ~PAGE_MASK)
1553	#endif
1554	goto out;
1555	}
1556
1557	flags |= MAP_FIXED;
1558	} else if ((shmflg & SHM_REMAP))
1559	goto out;
1560
1561	if (shmflg & SHM_RDONLY) {
1562	prot = PROT_READ;
1563	acc_mode = S_IRUGO;
1564	f_flags = O_RDONLY;
1565	} else {
1566	prot = PROT_READ | PROT_WRITE;
1567	acc_mode = S_IRUGO | S_IWUGO;
1568	f_flags = O_RDWR;
1569	}
1570	if (shmflg & SHM_EXEC) {
1571	prot |= PROT_EXEC;
1572	acc_mode |= S_IXUGO;
1573	}
1574
1575	/*
1576	* We cannot rely on the fs check since SYSV IPC does have an
1577	* additional creator id...
1578	*/
1579	ns = current->nsproxy->ipc_ns;
1580	rcu_read_lock();
1581	shp = shm_obtain_object_check(ns, id: shmid);
1582	if (IS_ERR(ptr: shp)) {
1583	err = PTR_ERR(ptr: shp);
1584	goto out_unlock;
1585	}
1586
1587	err = -EACCES;
1588	if (ipcperms(ns, ipcp: &shp->shm_perm, flg: acc_mode))
1589	goto out_unlock;
1590
1591	err = security_shm_shmat(shp: &shp->shm_perm, shmaddr, shmflg);
1592	if (err)
1593	goto out_unlock;
1594
1595	ipc_lock_object(perm: &shp->shm_perm);
1596
1597	/* check if shm_destroy() is tearing down shp */
1598	if (!ipc_valid_object(perm: &shp->shm_perm)) {
1599	ipc_unlock_object(perm: &shp->shm_perm);
1600	err = -EIDRM;
1601	goto out_unlock;
1602	}
1603
1604	/*
1605	* We need to take a reference to the real shm file to prevent the
1606	* pointer from becoming stale in cases where the lifetime of the outer
1607	* file extends beyond that of the shm segment. It's not usually
1608	* possible, but it can happen during remap_file_pages() emulation as
1609	* that unmaps the memory, then does ->mmap() via file reference only.
1610	* We'll deny the ->mmap() if the shm segment was since removed, but to
1611	* detect shm ID reuse we need to compare the file pointers.
1612	*/
1613	base = get_file(f: shp->shm_file);
1614	shp->shm_nattch++;
1615	size = i_size_read(inode: file_inode(f: base));
1616	ipc_unlock_object(perm: &shp->shm_perm);
1617	rcu_read_unlock();
1618
1619	err = -ENOMEM;
1620	sfd = kzalloc(size: sizeof(*sfd), GFP_KERNEL);
1621	if (!sfd) {
1622	fput(base);
1623	goto out_nattch;
1624	}
1625
1626	file = alloc_file_clone(base, flags: f_flags,
1627	is_file_hugepages(file: base) ?
1628	&shm_file_operations_huge :
1629	&shm_file_operations);
1630	err = PTR_ERR(ptr: file);
1631	if (IS_ERR(ptr: file)) {
1632	kfree(objp: sfd);
1633	fput(base);
1634	goto out_nattch;
1635	}
1636
1637	sfd->id = shp->shm_perm.id;
1638	sfd->ns = get_ipc_ns(ns);
1639	sfd->file = base;
1640	sfd->vm_ops = NULL;
1641	file->private_data = sfd;
1642
1643	err = security_mmap_file(file, prot, flags);
1644	if (err)
1645	goto out_fput;
1646
1647	if (mmap_write_lock_killable(current->mm)) {
1648	err = -EINTR;
1649	goto out_fput;
1650	}
1651
1652	if (addr && !(shmflg & SHM_REMAP)) {
1653	err = -EINVAL;
1654	if (addr + size < addr)
1655	goto invalid;
1656
1657	if (find_vma_intersection(current->mm, start_addr: addr, end_addr: addr + size))
1658	goto invalid;
1659	}
1660
1661	addr = do_mmap(file, addr, len: size, prot, flags, vm_flags: 0, pgoff: 0, populate: &populate, NULL);
1662	*raddr = addr;
1663	err = 0;
1664	if (IS_ERR_VALUE(addr))
1665	err = (long)addr;
1666	invalid:
1667	mmap_write_unlock(current->mm);
1668	if (populate)
1669	mm_populate(addr, len: populate);
1670
1671	out_fput:
1672	fput(file);
1673
1674	out_nattch:
1675	down_write(sem: &shm_ids(ns).rwsem);
1676	shp = shm_lock(ns, id: shmid);
1677	shp->shm_nattch--;
1678
1679	if (shm_may_destroy(shp))
1680	shm_destroy(ns, shp);
1681	else
1682	shm_unlock(shp);
1683	up_write(sem: &shm_ids(ns).rwsem);
1684	return err;
1685
1686	out_unlock:
1687	rcu_read_unlock();
1688	out:
1689	return err;
1690	}
1691
1692	SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
1693	{
1694	unsigned long ret;
1695	long err;
1696
1697	err = do_shmat(shmid, shmaddr, shmflg, raddr: &ret, SHMLBA);
1698	if (err)
1699	return err;
1700	force_successful_syscall_return();
1701	return (long)ret;
1702	}
1703
1704	#ifdef CONFIG_COMPAT
1705
1706	#ifndef COMPAT_SHMLBA
1707	#define COMPAT_SHMLBA SHMLBA
1708	#endif
1709
1710	COMPAT_SYSCALL_DEFINE3(shmat, int, shmid, compat_uptr_t, shmaddr, int, shmflg)
1711	{
1712	unsigned long ret;
1713	long err;
1714
1715	err = do_shmat(shmid, shmaddr: compat_ptr(uptr: shmaddr), shmflg, raddr: &ret, COMPAT_SHMLBA);
1716	if (err)
1717	return err;
1718	force_successful_syscall_return();
1719	return (long)ret;
1720	}
1721	#endif
1722
1723	/*
1724	* detach and kill segment if marked destroyed.
1725	* The work is done in shm_close.
1726	*/
1727	long ksys_shmdt(char __user *shmaddr)
1728	{
1729	struct mm_struct *mm = current->mm;
1730	struct vm_area_struct *vma;
1731	unsigned long addr = (unsigned long)shmaddr;
1732	int retval = -EINVAL;
1733	#ifdef CONFIG_MMU
1734	loff_t size = 0;
1735	struct file *file;
1736	VMA_ITERATOR(vmi, mm, addr);
1737	#endif
1738
1739	if (addr & ~PAGE_MASK)
1740	return retval;
1741
1742	if (mmap_write_lock_killable(mm))
1743	return -EINTR;
1744
1745	/*
1746	* This function tries to be smart and unmap shm segments that
1747	* were modified by partial mlock or munmap calls:
1748	* - It first determines the size of the shm segment that should be
1749	* unmapped: It searches for a vma that is backed by shm and that
1750	* started at address shmaddr. It records it's size and then unmaps
1751	* it.
1752	* - Then it unmaps all shm vmas that started at shmaddr and that
1753	* are within the initially determined size and that are from the
1754	* same shm segment from which we determined the size.
1755	* Errors from do_munmap are ignored: the function only fails if
1756	* it's called with invalid parameters or if it's called to unmap
1757	* a part of a vma. Both calls in this function are for full vmas,
1758	* the parameters are directly copied from the vma itself and always
1759	* valid - therefore do_munmap cannot fail. (famous last words?)
1760	*/
1761	/*
1762	* If it had been mremap()'d, the starting address would not
1763	* match the usual checks anyway. So assume all vma's are
1764	* above the starting address given.
1765	*/
1766
1767	#ifdef CONFIG_MMU
1768	for_each_vma(vmi, vma) {
1769	/*
1770	* Check if the starting address would match, i.e. it's
1771	* a fragment created by mprotect() and/or munmap(), or it
1772	* otherwise it starts at this address with no hassles.
1773	*/
1774	if ((vma->vm_ops == &shm_vm_ops) &&
1775	(vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1776
1777	/*
1778	* Record the file of the shm segment being
1779	* unmapped. With mremap(), someone could place
1780	* page from another segment but with equal offsets
1781	* in the range we are unmapping.
1782	*/
1783	file = vma->vm_file;
1784	size = i_size_read(inode: file_inode(f: vma->vm_file));
1785	do_vma_munmap(vmi: &vmi, vma, start: vma->vm_start, end: vma->vm_end,
1786	NULL, unlock: false);
1787	/*
1788	* We discovered the size of the shm segment, so
1789	* break out of here and fall through to the next
1790	* loop that uses the size information to stop
1791	* searching for matching vma's.
1792	*/
1793	retval = 0;
1794	vma = vma_next(vmi: &vmi);
1795	break;
1796	}
1797	}
1798
1799	/*
1800	* We need look no further than the maximum address a fragment
1801	* could possibly have landed at. Also cast things to loff_t to
1802	* prevent overflows and make comparisons vs. equal-width types.
1803	*/
1804	size = PAGE_ALIGN(size);
1805	while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1806	/* finding a matching vma now does not alter retval */
1807	if ((vma->vm_ops == &shm_vm_ops) &&
1808	((vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) &&
1809	(vma->vm_file == file)) {
1810	do_vma_munmap(vmi: &vmi, vma, start: vma->vm_start, end: vma->vm_end,
1811	NULL, unlock: false);
1812	}
1813
1814	vma = vma_next(vmi: &vmi);
1815	}
1816
1817	#else /* CONFIG_MMU */
1818	vma = vma_lookup(mm, addr);
1819	/* under NOMMU conditions, the exact address to be destroyed must be
1820	* given
1821	*/
1822	if (vma && vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1823	do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start, NULL);
1824	retval = 0;
1825	}
1826
1827	#endif
1828
1829	mmap_write_unlock(mm);
1830	return retval;
1831	}
1832
1833	SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
1834	{
1835	return ksys_shmdt(shmaddr);
1836	}
1837
1838	#ifdef CONFIG_PROC_FS
1839	static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1840	{
1841	struct pid_namespace *pid_ns = ipc_seq_pid_ns(s);
1842	struct user_namespace *user_ns = seq_user_ns(seq: s);
1843	struct kern_ipc_perm *ipcp = it;
1844	struct shmid_kernel *shp;
1845	unsigned long rss = 0, swp = 0;
1846
1847	shp = container_of(ipcp, struct shmid_kernel, shm_perm);
1848	shm_add_rss_swap(shp, rss_add: &rss, swp_add: &swp);
1849
1850	#if BITS_PER_LONG <= 32
1851	#define SIZE_SPEC "%10lu"
1852	#else
1853	#define SIZE_SPEC "%21lu"
1854	#endif
1855
1856	seq_printf(m: s,
1857	fmt: "%10d %10d %4o " SIZE_SPEC " %5u %5u "
1858	"%5lu %5u %5u %5u %5u %10llu %10llu %10llu "
1859	SIZE_SPEC " " SIZE_SPEC "\n",
1860	shp->shm_perm.key,
1861	shp->shm_perm.id,
1862	shp->shm_perm.mode,
1863	shp->shm_segsz,
1864	pid_nr_ns(pid: shp->shm_cprid, ns: pid_ns),
1865	pid_nr_ns(pid: shp->shm_lprid, ns: pid_ns),
1866	shp->shm_nattch,
1867	from_kuid_munged(to: user_ns, uid: shp->shm_perm.uid),
1868	from_kgid_munged(to: user_ns, gid: shp->shm_perm.gid),
1869	from_kuid_munged(to: user_ns, uid: shp->shm_perm.cuid),
1870	from_kgid_munged(to: user_ns, gid: shp->shm_perm.cgid),
1871	shp->shm_atim,
1872	shp->shm_dtim,
1873	shp->shm_ctim,
1874	rss * PAGE_SIZE,
1875	swp * PAGE_SIZE);
1876
1877	return 0;
1878	}
1879	#endif
1880