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