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1/*
2 * linux/ipc/shm.c
3 * Copyright (C) 1992, 1993 Krishna Balasubramanian
4 * Many improvements/fixes by Bruno Haible.
5 * Replaced `struct shm_desc' by `struct vm_area_struct', July 1994.
6 * Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli.
7 *
8 * /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
9 * BIGMEM support, Andrea Arcangeli <andrea@suse.de>
10 * SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr>
11 * HIGHMEM support, Ingo Molnar <mingo@redhat.com>
12 * Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <cr@sap.com>
13 * Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com>
14 * Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com>
15 *
16 * support for audit of ipc object properties and permission changes
17 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
18 *
19 * namespaces support
20 * OpenVZ, SWsoft Inc.
21 * Pavel Emelianov <xemul@openvz.org>
22 */
23
24#include <linux/slab.h>
25#include <linux/mm.h>
26#include <linux/hugetlb.h>
27#include <linux/shm.h>
28#include <linux/init.h>
29#include <linux/file.h>
30#include <linux/mman.h>
31#include <linux/shmem_fs.h>
32#include <linux/security.h>
33#include <linux/syscalls.h>
34#include <linux/audit.h>
35#include <linux/capability.h>
36#include <linux/ptrace.h>
37#include <linux/seq_file.h>
38#include <linux/rwsem.h>
39#include <linux/nsproxy.h>
40#include <linux/mount.h>
41#include <linux/ipc_namespace.h>
42
43#include <asm/uaccess.h>
44
45#include "util.h"
46
47struct shm_file_data {
48 int id;
49 struct ipc_namespace *ns;
50 struct file *file;
51 const struct vm_operations_struct *vm_ops;
52};
53
54#define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
55
56static const struct file_operations shm_file_operations;
57static const struct vm_operations_struct shm_vm_ops;
58
59#define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS])
60
61#define shm_unlock(shp) \
62 ipc_unlock(&(shp)->shm_perm)
63
64static int newseg(struct ipc_namespace *, struct ipc_params *);
65static void shm_open(struct vm_area_struct *vma);
66static void shm_close(struct vm_area_struct *vma);
67static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
68#ifdef CONFIG_PROC_FS
69static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
70#endif
71
72void shm_init_ns(struct ipc_namespace *ns)
73{
74 ns->shm_ctlmax = SHMMAX;
75 ns->shm_ctlall = SHMALL;
76 ns->shm_ctlmni = SHMMNI;
77 ns->shm_rmid_forced = 0;
78 ns->shm_tot = 0;
79 ipc_init_ids(&shm_ids(ns));
80}
81
82/*
83 * Called with shm_ids.rw_mutex (writer) and the shp structure locked.
84 * Only shm_ids.rw_mutex remains locked on exit.
85 */
86static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
87{
88 struct shmid_kernel *shp;
89 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
90
91 if (shp->shm_nattch){
92 shp->shm_perm.mode |= SHM_DEST;
93 /* Do not find it any more */
94 shp->shm_perm.key = IPC_PRIVATE;
95 shm_unlock(shp);
96 } else
97 shm_destroy(ns, shp);
98}
99
100#ifdef CONFIG_IPC_NS
101void shm_exit_ns(struct ipc_namespace *ns)
102{
103 free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
104 idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
105}
106#endif
107
108static int __init ipc_ns_init(void)
109{
110 shm_init_ns(&init_ipc_ns);
111 return 0;
112}
113
114pure_initcall(ipc_ns_init);
115
116void __init shm_init (void)
117{
118 ipc_init_proc_interface("sysvipc/shm",
119#if BITS_PER_LONG <= 32
120 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
121#else
122 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n",
123#endif
124 IPC_SHM_IDS, sysvipc_shm_proc_show);
125}
126
127/*
128 * shm_lock_(check_) routines are called in the paths where the rw_mutex
129 * is not necessarily held.
130 */
131static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
132{
133 struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
134
135 if (IS_ERR(ipcp))
136 return (struct shmid_kernel *)ipcp;
137
138 return container_of(ipcp, struct shmid_kernel, shm_perm);
139}
140
141static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
142{
143 rcu_read_lock();
144 spin_lock(&ipcp->shm_perm.lock);
145}
146
147static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
148 int id)
149{
150 struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);
151
152 if (IS_ERR(ipcp))
153 return (struct shmid_kernel *)ipcp;
154
155 return container_of(ipcp, struct shmid_kernel, shm_perm);
156}
157
158static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
159{
160 ipc_rmid(&shm_ids(ns), &s->shm_perm);
161}
162
163
164/* This is called by fork, once for every shm attach. */
165static void shm_open(struct vm_area_struct *vma)
166{
167 struct file *file = vma->vm_file;
168 struct shm_file_data *sfd = shm_file_data(file);
169 struct shmid_kernel *shp;
170
171 shp = shm_lock(sfd->ns, sfd->id);
172 BUG_ON(IS_ERR(shp));
173 shp->shm_atim = get_seconds();
174 shp->shm_lprid = task_tgid_vnr(current);
175 shp->shm_nattch++;
176 shm_unlock(shp);
177}
178
179/*
180 * shm_destroy - free the struct shmid_kernel
181 *
182 * @ns: namespace
183 * @shp: struct to free
184 *
185 * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
186 * but returns with shp unlocked and freed.
187 */
188static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
189{
190 ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
191 shm_rmid(ns, shp);
192 shm_unlock(shp);
193 if (!is_file_hugepages(shp->shm_file))
194 shmem_lock(shp->shm_file, 0, shp->mlock_user);
195 else if (shp->mlock_user)
196 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
197 shp->mlock_user);
198 fput (shp->shm_file);
199 security_shm_free(shp);
200 ipc_rcu_putref(shp);
201}
202
203/*
204 * shm_may_destroy - identifies whether shm segment should be destroyed now
205 *
206 * Returns true if and only if there are no active users of the segment and
207 * one of the following is true:
208 *
209 * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
210 *
211 * 2) sysctl kernel.shm_rmid_forced is set to 1.
212 */
213static bool shm_may_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
214{
215 return (shp->shm_nattch == 0) &&
216 (ns->shm_rmid_forced ||
217 (shp->shm_perm.mode & SHM_DEST));
218}
219
220/*
221 * remove the attach descriptor vma.
222 * free memory for segment if it is marked destroyed.
223 * The descriptor has already been removed from the current->mm->mmap list
224 * and will later be kfree()d.
225 */
226static void shm_close(struct vm_area_struct *vma)
227{
228 struct file * file = vma->vm_file;
229 struct shm_file_data *sfd = shm_file_data(file);
230 struct shmid_kernel *shp;
231 struct ipc_namespace *ns = sfd->ns;
232
233 down_write(&shm_ids(ns).rw_mutex);
234 /* remove from the list of attaches of the shm segment */
235 shp = shm_lock(ns, sfd->id);
236 BUG_ON(IS_ERR(shp));
237 shp->shm_lprid = task_tgid_vnr(current);
238 shp->shm_dtim = get_seconds();
239 shp->shm_nattch--;
240 if (shm_may_destroy(ns, shp))
241 shm_destroy(ns, shp);
242 else
243 shm_unlock(shp);
244 up_write(&shm_ids(ns).rw_mutex);
245}
246
247/* Called with ns->shm_ids(ns).rw_mutex locked */
248static int shm_try_destroy_current(int id, void *p, void *data)
249{
250 struct ipc_namespace *ns = data;
251 struct kern_ipc_perm *ipcp = p;
252 struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
253
254 if (shp->shm_creator != current)
255 return 0;
256
257 /*
258 * Mark it as orphaned to destroy the segment when
259 * kernel.shm_rmid_forced is changed.
260 * It is noop if the following shm_may_destroy() returns true.
261 */
262 shp->shm_creator = NULL;
263
264 /*
265 * Don't even try to destroy it. If shm_rmid_forced=0 and IPC_RMID
266 * is not set, it shouldn't be deleted here.
267 */
268 if (!ns->shm_rmid_forced)
269 return 0;
270
271 if (shm_may_destroy(ns, shp)) {
272 shm_lock_by_ptr(shp);
273 shm_destroy(ns, shp);
274 }
275 return 0;
276}
277
278/* Called with ns->shm_ids(ns).rw_mutex locked */
279static int shm_try_destroy_orphaned(int id, void *p, void *data)
280{
281 struct ipc_namespace *ns = data;
282 struct kern_ipc_perm *ipcp = p;
283 struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
284
285 /*
286 * We want to destroy segments without users and with already
287 * exit'ed originating process.
288 *
289 * As shp->* are changed under rw_mutex, it's safe to skip shp locking.
290 */
291 if (shp->shm_creator != NULL)
292 return 0;
293
294 if (shm_may_destroy(ns, shp)) {
295 shm_lock_by_ptr(shp);
296 shm_destroy(ns, shp);
297 }
298 return 0;
299}
300
301void shm_destroy_orphaned(struct ipc_namespace *ns)
302{
303 down_write(&shm_ids(ns).rw_mutex);
304 if (shm_ids(ns).in_use)
305 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
306 up_write(&shm_ids(ns).rw_mutex);
307}
308
309
310void exit_shm(struct task_struct *task)
311{
312 struct ipc_namespace *ns = task->nsproxy->ipc_ns;
313
314 if (shm_ids(ns).in_use == 0)
315 return;
316
317 /* Destroy all already created segments, but not mapped yet */
318 down_write(&shm_ids(ns).rw_mutex);
319 if (shm_ids(ns).in_use)
320 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_current, ns);
321 up_write(&shm_ids(ns).rw_mutex);
322}
323
324static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
325{
326 struct file *file = vma->vm_file;
327 struct shm_file_data *sfd = shm_file_data(file);
328
329 return sfd->vm_ops->fault(vma, vmf);
330}
331
332#ifdef CONFIG_NUMA
333static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
334{
335 struct file *file = vma->vm_file;
336 struct shm_file_data *sfd = shm_file_data(file);
337 int err = 0;
338 if (sfd->vm_ops->set_policy)
339 err = sfd->vm_ops->set_policy(vma, new);
340 return err;
341}
342
343static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
344 unsigned long addr)
345{
346 struct file *file = vma->vm_file;
347 struct shm_file_data *sfd = shm_file_data(file);
348 struct mempolicy *pol = NULL;
349
350 if (sfd->vm_ops->get_policy)
351 pol = sfd->vm_ops->get_policy(vma, addr);
352 else if (vma->vm_policy)
353 pol = vma->vm_policy;
354
355 return pol;
356}
357#endif
358
359static int shm_mmap(struct file * file, struct vm_area_struct * vma)
360{
361 struct shm_file_data *sfd = shm_file_data(file);
362 int ret;
363
364 ret = sfd->file->f_op->mmap(sfd->file, vma);
365 if (ret != 0)
366 return ret;
367 sfd->vm_ops = vma->vm_ops;
368#ifdef CONFIG_MMU
369 BUG_ON(!sfd->vm_ops->fault);
370#endif
371 vma->vm_ops = &shm_vm_ops;
372 shm_open(vma);
373
374 return ret;
375}
376
377static int shm_release(struct inode *ino, struct file *file)
378{
379 struct shm_file_data *sfd = shm_file_data(file);
380
381 put_ipc_ns(sfd->ns);
382 shm_file_data(file) = NULL;
383 kfree(sfd);
384 return 0;
385}
386
387static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
388{
389 struct shm_file_data *sfd = shm_file_data(file);
390
391 if (!sfd->file->f_op->fsync)
392 return -EINVAL;
393 return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
394}
395
396static unsigned long shm_get_unmapped_area(struct file *file,
397 unsigned long addr, unsigned long len, unsigned long pgoff,
398 unsigned long flags)
399{
400 struct shm_file_data *sfd = shm_file_data(file);
401 return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
402 pgoff, flags);
403}
404
405static const struct file_operations shm_file_operations = {
406 .mmap = shm_mmap,
407 .fsync = shm_fsync,
408 .release = shm_release,
409#ifndef CONFIG_MMU
410 .get_unmapped_area = shm_get_unmapped_area,
411#endif
412 .llseek = noop_llseek,
413};
414
415static const struct file_operations shm_file_operations_huge = {
416 .mmap = shm_mmap,
417 .fsync = shm_fsync,
418 .release = shm_release,
419 .get_unmapped_area = shm_get_unmapped_area,
420 .llseek = noop_llseek,
421};
422
423int is_file_shm_hugepages(struct file *file)
424{
425 return file->f_op == &shm_file_operations_huge;
426}
427
428static const struct vm_operations_struct shm_vm_ops = {
429 .open = shm_open, /* callback for a new vm-area open */
430 .close = shm_close, /* callback for when the vm-area is released */
431 .fault = shm_fault,
432#if defined(CONFIG_NUMA)
433 .set_policy = shm_set_policy,
434 .get_policy = shm_get_policy,
435#endif
436};
437
438/**
439 * newseg - Create a new shared memory segment
440 * @ns: namespace
441 * @params: ptr to the structure that contains key, size and shmflg
442 *
443 * Called with shm_ids.rw_mutex held as a writer.
444 */
445
446static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
447{
448 key_t key = params->key;
449 int shmflg = params->flg;
450 size_t size = params->u.size;
451 int error;
452 struct shmid_kernel *shp;
453 int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
454 struct file * file;
455 char name[13];
456 int id;
457 vm_flags_t acctflag = 0;
458
459 if (size < SHMMIN || size > ns->shm_ctlmax)
460 return -EINVAL;
461
462 if (ns->shm_tot + numpages > ns->shm_ctlall)
463 return -ENOSPC;
464
465 shp = ipc_rcu_alloc(sizeof(*shp));
466 if (!shp)
467 return -ENOMEM;
468
469 shp->shm_perm.key = key;
470 shp->shm_perm.mode = (shmflg & S_IRWXUGO);
471 shp->mlock_user = NULL;
472
473 shp->shm_perm.security = NULL;
474 error = security_shm_alloc(shp);
475 if (error) {
476 ipc_rcu_putref(shp);
477 return error;
478 }
479
480 sprintf (name, "SYSV%08x", key);
481 if (shmflg & SHM_HUGETLB) {
482 /* hugetlb_file_setup applies strict accounting */
483 if (shmflg & SHM_NORESERVE)
484 acctflag = VM_NORESERVE;
485 file = hugetlb_file_setup(name, size, acctflag,
486 &shp->mlock_user, HUGETLB_SHMFS_INODE);
487 } else {
488 /*
489 * Do not allow no accounting for OVERCOMMIT_NEVER, even
490 * if it's asked for.
491 */
492 if ((shmflg & SHM_NORESERVE) &&
493 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
494 acctflag = VM_NORESERVE;
495 file = shmem_file_setup(name, size, acctflag);
496 }
497 error = PTR_ERR(file);
498 if (IS_ERR(file))
499 goto no_file;
500
501 id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
502 if (id < 0) {
503 error = id;
504 goto no_id;
505 }
506
507 shp->shm_cprid = task_tgid_vnr(current);
508 shp->shm_lprid = 0;
509 shp->shm_atim = shp->shm_dtim = 0;
510 shp->shm_ctim = get_seconds();
511 shp->shm_segsz = size;
512 shp->shm_nattch = 0;
513 shp->shm_file = file;
514 shp->shm_creator = current;
515 /*
516 * shmid gets reported as "inode#" in /proc/pid/maps.
517 * proc-ps tools use this. Changing this will break them.
518 */
519 file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
520
521 ns->shm_tot += numpages;
522 error = shp->shm_perm.id;
523 shm_unlock(shp);
524 return error;
525
526no_id:
527 if (is_file_hugepages(file) && shp->mlock_user)
528 user_shm_unlock(size, shp->mlock_user);
529 fput(file);
530no_file:
531 security_shm_free(shp);
532 ipc_rcu_putref(shp);
533 return error;
534}
535
536/*
537 * Called with shm_ids.rw_mutex and ipcp locked.
538 */
539static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
540{
541 struct shmid_kernel *shp;
542
543 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
544 return security_shm_associate(shp, shmflg);
545}
546
547/*
548 * Called with shm_ids.rw_mutex and ipcp locked.
549 */
550static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
551 struct ipc_params *params)
552{
553 struct shmid_kernel *shp;
554
555 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
556 if (shp->shm_segsz < params->u.size)
557 return -EINVAL;
558
559 return 0;
560}
561
562SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
563{
564 struct ipc_namespace *ns;
565 struct ipc_ops shm_ops;
566 struct ipc_params shm_params;
567
568 ns = current->nsproxy->ipc_ns;
569
570 shm_ops.getnew = newseg;
571 shm_ops.associate = shm_security;
572 shm_ops.more_checks = shm_more_checks;
573
574 shm_params.key = key;
575 shm_params.flg = shmflg;
576 shm_params.u.size = size;
577
578 return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
579}
580
581static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
582{
583 switch(version) {
584 case IPC_64:
585 return copy_to_user(buf, in, sizeof(*in));
586 case IPC_OLD:
587 {
588 struct shmid_ds out;
589
590 memset(&out, 0, sizeof(out));
591 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
592 out.shm_segsz = in->shm_segsz;
593 out.shm_atime = in->shm_atime;
594 out.shm_dtime = in->shm_dtime;
595 out.shm_ctime = in->shm_ctime;
596 out.shm_cpid = in->shm_cpid;
597 out.shm_lpid = in->shm_lpid;
598 out.shm_nattch = in->shm_nattch;
599
600 return copy_to_user(buf, &out, sizeof(out));
601 }
602 default:
603 return -EINVAL;
604 }
605}
606
607static inline unsigned long
608copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
609{
610 switch(version) {
611 case IPC_64:
612 if (copy_from_user(out, buf, sizeof(*out)))
613 return -EFAULT;
614 return 0;
615 case IPC_OLD:
616 {
617 struct shmid_ds tbuf_old;
618
619 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
620 return -EFAULT;
621
622 out->shm_perm.uid = tbuf_old.shm_perm.uid;
623 out->shm_perm.gid = tbuf_old.shm_perm.gid;
624 out->shm_perm.mode = tbuf_old.shm_perm.mode;
625
626 return 0;
627 }
628 default:
629 return -EINVAL;
630 }
631}
632
633static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
634{
635 switch(version) {
636 case IPC_64:
637 return copy_to_user(buf, in, sizeof(*in));
638 case IPC_OLD:
639 {
640 struct shminfo out;
641
642 if(in->shmmax > INT_MAX)
643 out.shmmax = INT_MAX;
644 else
645 out.shmmax = (int)in->shmmax;
646
647 out.shmmin = in->shmmin;
648 out.shmmni = in->shmmni;
649 out.shmseg = in->shmseg;
650 out.shmall = in->shmall;
651
652 return copy_to_user(buf, &out, sizeof(out));
653 }
654 default:
655 return -EINVAL;
656 }
657}
658
659/*
660 * Calculate and add used RSS and swap pages of a shm.
661 * Called with shm_ids.rw_mutex held as a reader
662 */
663static void shm_add_rss_swap(struct shmid_kernel *shp,
664 unsigned long *rss_add, unsigned long *swp_add)
665{
666 struct inode *inode;
667
668 inode = shp->shm_file->f_path.dentry->d_inode;
669
670 if (is_file_hugepages(shp->shm_file)) {
671 struct address_space *mapping = inode->i_mapping;
672 struct hstate *h = hstate_file(shp->shm_file);
673 *rss_add += pages_per_huge_page(h) * mapping->nrpages;
674 } else {
675#ifdef CONFIG_SHMEM
676 struct shmem_inode_info *info = SHMEM_I(inode);
677 spin_lock(&info->lock);
678 *rss_add += inode->i_mapping->nrpages;
679 *swp_add += info->swapped;
680 spin_unlock(&info->lock);
681#else
682 *rss_add += inode->i_mapping->nrpages;
683#endif
684 }
685}
686
687/*
688 * Called with shm_ids.rw_mutex held as a reader
689 */
690static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
691 unsigned long *swp)
692{
693 int next_id;
694 int total, in_use;
695
696 *rss = 0;
697 *swp = 0;
698
699 in_use = shm_ids(ns).in_use;
700
701 for (total = 0, next_id = 0; total < in_use; next_id++) {
702 struct kern_ipc_perm *ipc;
703 struct shmid_kernel *shp;
704
705 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
706 if (ipc == NULL)
707 continue;
708 shp = container_of(ipc, struct shmid_kernel, shm_perm);
709
710 shm_add_rss_swap(shp, rss, swp);
711
712 total++;
713 }
714}
715
716/*
717 * This function handles some shmctl commands which require the rw_mutex
718 * to be held in write mode.
719 * NOTE: no locks must be held, the rw_mutex is taken inside this function.
720 */
721static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
722 struct shmid_ds __user *buf, int version)
723{
724 struct kern_ipc_perm *ipcp;
725 struct shmid64_ds shmid64;
726 struct shmid_kernel *shp;
727 int err;
728
729 if (cmd == IPC_SET) {
730 if (copy_shmid_from_user(&shmid64, buf, version))
731 return -EFAULT;
732 }
733
734 ipcp = ipcctl_pre_down(ns, &shm_ids(ns), shmid, cmd,
735 &shmid64.shm_perm, 0);
736 if (IS_ERR(ipcp))
737 return PTR_ERR(ipcp);
738
739 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
740
741 err = security_shm_shmctl(shp, cmd);
742 if (err)
743 goto out_unlock;
744 switch (cmd) {
745 case IPC_RMID:
746 do_shm_rmid(ns, ipcp);
747 goto out_up;
748 case IPC_SET:
749 ipc_update_perm(&shmid64.shm_perm, ipcp);
750 shp->shm_ctim = get_seconds();
751 break;
752 default:
753 err = -EINVAL;
754 }
755out_unlock:
756 shm_unlock(shp);
757out_up:
758 up_write(&shm_ids(ns).rw_mutex);
759 return err;
760}
761
762SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
763{
764 struct shmid_kernel *shp;
765 int err, version;
766 struct ipc_namespace *ns;
767
768 if (cmd < 0 || shmid < 0) {
769 err = -EINVAL;
770 goto out;
771 }
772
773 version = ipc_parse_version(&cmd);
774 ns = current->nsproxy->ipc_ns;
775
776 switch (cmd) { /* replace with proc interface ? */
777 case IPC_INFO:
778 {
779 struct shminfo64 shminfo;
780
781 err = security_shm_shmctl(NULL, cmd);
782 if (err)
783 return err;
784
785 memset(&shminfo, 0, sizeof(shminfo));
786 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
787 shminfo.shmmax = ns->shm_ctlmax;
788 shminfo.shmall = ns->shm_ctlall;
789
790 shminfo.shmmin = SHMMIN;
791 if(copy_shminfo_to_user (buf, &shminfo, version))
792 return -EFAULT;
793
794 down_read(&shm_ids(ns).rw_mutex);
795 err = ipc_get_maxid(&shm_ids(ns));
796 up_read(&shm_ids(ns).rw_mutex);
797
798 if(err<0)
799 err = 0;
800 goto out;
801 }
802 case SHM_INFO:
803 {
804 struct shm_info shm_info;
805
806 err = security_shm_shmctl(NULL, cmd);
807 if (err)
808 return err;
809
810 memset(&shm_info, 0, sizeof(shm_info));
811 down_read(&shm_ids(ns).rw_mutex);
812 shm_info.used_ids = shm_ids(ns).in_use;
813 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
814 shm_info.shm_tot = ns->shm_tot;
815 shm_info.swap_attempts = 0;
816 shm_info.swap_successes = 0;
817 err = ipc_get_maxid(&shm_ids(ns));
818 up_read(&shm_ids(ns).rw_mutex);
819 if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
820 err = -EFAULT;
821 goto out;
822 }
823
824 err = err < 0 ? 0 : err;
825 goto out;
826 }
827 case SHM_STAT:
828 case IPC_STAT:
829 {
830 struct shmid64_ds tbuf;
831 int result;
832
833 if (cmd == SHM_STAT) {
834 shp = shm_lock(ns, shmid);
835 if (IS_ERR(shp)) {
836 err = PTR_ERR(shp);
837 goto out;
838 }
839 result = shp->shm_perm.id;
840 } else {
841 shp = shm_lock_check(ns, shmid);
842 if (IS_ERR(shp)) {
843 err = PTR_ERR(shp);
844 goto out;
845 }
846 result = 0;
847 }
848 err = -EACCES;
849 if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
850 goto out_unlock;
851 err = security_shm_shmctl(shp, cmd);
852 if (err)
853 goto out_unlock;
854 memset(&tbuf, 0, sizeof(tbuf));
855 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
856 tbuf.shm_segsz = shp->shm_segsz;
857 tbuf.shm_atime = shp->shm_atim;
858 tbuf.shm_dtime = shp->shm_dtim;
859 tbuf.shm_ctime = shp->shm_ctim;
860 tbuf.shm_cpid = shp->shm_cprid;
861 tbuf.shm_lpid = shp->shm_lprid;
862 tbuf.shm_nattch = shp->shm_nattch;
863 shm_unlock(shp);
864 if(copy_shmid_to_user (buf, &tbuf, version))
865 err = -EFAULT;
866 else
867 err = result;
868 goto out;
869 }
870 case SHM_LOCK:
871 case SHM_UNLOCK:
872 {
873 struct file *uninitialized_var(shm_file);
874
875 lru_add_drain_all(); /* drain pagevecs to lru lists */
876
877 shp = shm_lock_check(ns, shmid);
878 if (IS_ERR(shp)) {
879 err = PTR_ERR(shp);
880 goto out;
881 }
882
883 audit_ipc_obj(&(shp->shm_perm));
884
885 if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
886 uid_t euid = current_euid();
887 err = -EPERM;
888 if (euid != shp->shm_perm.uid &&
889 euid != shp->shm_perm.cuid)
890 goto out_unlock;
891 if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK))
892 goto out_unlock;
893 }
894
895 err = security_shm_shmctl(shp, cmd);
896 if (err)
897 goto out_unlock;
898
899 if(cmd==SHM_LOCK) {
900 struct user_struct *user = current_user();
901 if (!is_file_hugepages(shp->shm_file)) {
902 err = shmem_lock(shp->shm_file, 1, user);
903 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
904 shp->shm_perm.mode |= SHM_LOCKED;
905 shp->mlock_user = user;
906 }
907 }
908 } else if (!is_file_hugepages(shp->shm_file)) {
909 shmem_lock(shp->shm_file, 0, shp->mlock_user);
910 shp->shm_perm.mode &= ~SHM_LOCKED;
911 shp->mlock_user = NULL;
912 }
913 shm_unlock(shp);
914 goto out;
915 }
916 case IPC_RMID:
917 case IPC_SET:
918 err = shmctl_down(ns, shmid, cmd, buf, version);
919 return err;
920 default:
921 return -EINVAL;
922 }
923
924out_unlock:
925 shm_unlock(shp);
926out:
927 return err;
928}
929
930/*
931 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
932 *
933 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
934 * "raddr" thing points to kernel space, and there has to be a wrapper around
935 * this.
936 */
937long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
938{
939 struct shmid_kernel *shp;
940 unsigned long addr;
941 unsigned long size;
942 struct file * file;
943 int err;
944 unsigned long flags;
945 unsigned long prot;
946 int acc_mode;
947 unsigned long user_addr;
948 struct ipc_namespace *ns;
949 struct shm_file_data *sfd;
950 struct path path;
951 fmode_t f_mode;
952
953 err = -EINVAL;
954 if (shmid < 0)
955 goto out;
956 else if ((addr = (ulong)shmaddr)) {
957 if (addr & (SHMLBA-1)) {
958 if (shmflg & SHM_RND)
959 addr &= ~(SHMLBA-1); /* round down */
960 else
961#ifndef __ARCH_FORCE_SHMLBA
962 if (addr & ~PAGE_MASK)
963#endif
964 goto out;
965 }
966 flags = MAP_SHARED | MAP_FIXED;
967 } else {
968 if ((shmflg & SHM_REMAP))
969 goto out;
970
971 flags = MAP_SHARED;
972 }
973
974 if (shmflg & SHM_RDONLY) {
975 prot = PROT_READ;
976 acc_mode = S_IRUGO;
977 f_mode = FMODE_READ;
978 } else {
979 prot = PROT_READ | PROT_WRITE;
980 acc_mode = S_IRUGO | S_IWUGO;
981 f_mode = FMODE_READ | FMODE_WRITE;
982 }
983 if (shmflg & SHM_EXEC) {
984 prot |= PROT_EXEC;
985 acc_mode |= S_IXUGO;
986 }
987
988 /*
989 * We cannot rely on the fs check since SYSV IPC does have an
990 * additional creator id...
991 */
992 ns = current->nsproxy->ipc_ns;
993 shp = shm_lock_check(ns, shmid);
994 if (IS_ERR(shp)) {
995 err = PTR_ERR(shp);
996 goto out;
997 }
998
999 err = -EACCES;
1000 if (ipcperms(ns, &shp->shm_perm, acc_mode))
1001 goto out_unlock;
1002
1003 err = security_shm_shmat(shp, shmaddr, shmflg);
1004 if (err)
1005 goto out_unlock;
1006
1007 path = shp->shm_file->f_path;
1008 path_get(&path);
1009 shp->shm_nattch++;
1010 size = i_size_read(path.dentry->d_inode);
1011 shm_unlock(shp);
1012
1013 err = -ENOMEM;
1014 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
1015 if (!sfd)
1016 goto out_put_dentry;
1017
1018 file = alloc_file(&path, f_mode,
1019 is_file_hugepages(shp->shm_file) ?
1020 &shm_file_operations_huge :
1021 &shm_file_operations);
1022 if (!file)
1023 goto out_free;
1024
1025 file->private_data = sfd;
1026 file->f_mapping = shp->shm_file->f_mapping;
1027 sfd->id = shp->shm_perm.id;
1028 sfd->ns = get_ipc_ns(ns);
1029 sfd->file = shp->shm_file;
1030 sfd->vm_ops = NULL;
1031
1032 down_write(¤t->mm->mmap_sem);
1033 if (addr && !(shmflg & SHM_REMAP)) {
1034 err = -EINVAL;
1035 if (find_vma_intersection(current->mm, addr, addr + size))
1036 goto invalid;
1037 /*
1038 * If shm segment goes below stack, make sure there is some
1039 * space left for the stack to grow (at least 4 pages).
1040 */
1041 if (addr < current->mm->start_stack &&
1042 addr > current->mm->start_stack - size - PAGE_SIZE * 5)
1043 goto invalid;
1044 }
1045
1046 user_addr = do_mmap (file, addr, size, prot, flags, 0);
1047 *raddr = user_addr;
1048 err = 0;
1049 if (IS_ERR_VALUE(user_addr))
1050 err = (long)user_addr;
1051invalid:
1052 up_write(¤t->mm->mmap_sem);
1053
1054 fput(file);
1055
1056out_nattch:
1057 down_write(&shm_ids(ns).rw_mutex);
1058 shp = shm_lock(ns, shmid);
1059 BUG_ON(IS_ERR(shp));
1060 shp->shm_nattch--;
1061 if (shm_may_destroy(ns, shp))
1062 shm_destroy(ns, shp);
1063 else
1064 shm_unlock(shp);
1065 up_write(&shm_ids(ns).rw_mutex);
1066
1067out:
1068 return err;
1069
1070out_unlock:
1071 shm_unlock(shp);
1072 goto out;
1073
1074out_free:
1075 kfree(sfd);
1076out_put_dentry:
1077 path_put(&path);
1078 goto out_nattch;
1079}
1080
1081SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
1082{
1083 unsigned long ret;
1084 long err;
1085
1086 err = do_shmat(shmid, shmaddr, shmflg, &ret);
1087 if (err)
1088 return err;
1089 force_successful_syscall_return();
1090 return (long)ret;
1091}
1092
1093/*
1094 * detach and kill segment if marked destroyed.
1095 * The work is done in shm_close.
1096 */
1097SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
1098{
1099 struct mm_struct *mm = current->mm;
1100 struct vm_area_struct *vma;
1101 unsigned long addr = (unsigned long)shmaddr;
1102 int retval = -EINVAL;
1103#ifdef CONFIG_MMU
1104 loff_t size = 0;
1105 struct vm_area_struct *next;
1106#endif
1107
1108 if (addr & ~PAGE_MASK)
1109 return retval;
1110
1111 down_write(&mm->mmap_sem);
1112
1113 /*
1114 * This function tries to be smart and unmap shm segments that
1115 * were modified by partial mlock or munmap calls:
1116 * - It first determines the size of the shm segment that should be
1117 * unmapped: It searches for a vma that is backed by shm and that
1118 * started at address shmaddr. It records it's size and then unmaps
1119 * it.
1120 * - Then it unmaps all shm vmas that started at shmaddr and that
1121 * are within the initially determined size.
1122 * Errors from do_munmap are ignored: the function only fails if
1123 * it's called with invalid parameters or if it's called to unmap
1124 * a part of a vma. Both calls in this function are for full vmas,
1125 * the parameters are directly copied from the vma itself and always
1126 * valid - therefore do_munmap cannot fail. (famous last words?)
1127 */
1128 /*
1129 * If it had been mremap()'d, the starting address would not
1130 * match the usual checks anyway. So assume all vma's are
1131 * above the starting address given.
1132 */
1133 vma = find_vma(mm, addr);
1134
1135#ifdef CONFIG_MMU
1136 while (vma) {
1137 next = vma->vm_next;
1138
1139 /*
1140 * Check if the starting address would match, i.e. it's
1141 * a fragment created by mprotect() and/or munmap(), or it
1142 * otherwise it starts at this address with no hassles.
1143 */
1144 if ((vma->vm_ops == &shm_vm_ops) &&
1145 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1146
1147
1148 size = vma->vm_file->f_path.dentry->d_inode->i_size;
1149 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1150 /*
1151 * We discovered the size of the shm segment, so
1152 * break out of here and fall through to the next
1153 * loop that uses the size information to stop
1154 * searching for matching vma's.
1155 */
1156 retval = 0;
1157 vma = next;
1158 break;
1159 }
1160 vma = next;
1161 }
1162
1163 /*
1164 * We need look no further than the maximum address a fragment
1165 * could possibly have landed at. Also cast things to loff_t to
1166 * prevent overflows and make comparisons vs. equal-width types.
1167 */
1168 size = PAGE_ALIGN(size);
1169 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1170 next = vma->vm_next;
1171
1172 /* finding a matching vma now does not alter retval */
1173 if ((vma->vm_ops == &shm_vm_ops) &&
1174 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1175
1176 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1177 vma = next;
1178 }
1179
1180#else /* CONFIG_MMU */
1181 /* under NOMMU conditions, the exact address to be destroyed must be
1182 * given */
1183 retval = -EINVAL;
1184 if (vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1185 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1186 retval = 0;
1187 }
1188
1189#endif
1190
1191 up_write(&mm->mmap_sem);
1192 return retval;
1193}
1194
1195#ifdef CONFIG_PROC_FS
1196static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1197{
1198 struct shmid_kernel *shp = it;
1199 unsigned long rss = 0, swp = 0;
1200
1201 shm_add_rss_swap(shp, &rss, &swp);
1202
1203#if BITS_PER_LONG <= 32
1204#define SIZE_SPEC "%10lu"
1205#else
1206#define SIZE_SPEC "%21lu"
1207#endif
1208
1209 return seq_printf(s,
1210 "%10d %10d %4o " SIZE_SPEC " %5u %5u "
1211 "%5lu %5u %5u %5u %5u %10lu %10lu %10lu "
1212 SIZE_SPEC " " SIZE_SPEC "\n",
1213 shp->shm_perm.key,
1214 shp->shm_perm.id,
1215 shp->shm_perm.mode,
1216 shp->shm_segsz,
1217 shp->shm_cprid,
1218 shp->shm_lprid,
1219 shp->shm_nattch,
1220 shp->shm_perm.uid,
1221 shp->shm_perm.gid,
1222 shp->shm_perm.cuid,
1223 shp->shm_perm.cgid,
1224 shp->shm_atim,
1225 shp->shm_dtim,
1226 shp->shm_ctim,
1227 rss * PAGE_SIZE,
1228 swp * PAGE_SIZE);
1229}
1230#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 <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 int shm_more_checks(struct kern_ipc_perm *ipcp, struct ipc_params *params)
715{
716 struct shmid_kernel *shp;
717
718 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
719 if (shp->shm_segsz < params->u.size)
720 return -EINVAL;
721
722 return 0;
723}
724
725long ksys_shmget(key_t key, size_t size, int shmflg)
726{
727 struct ipc_namespace *ns;
728 static const struct ipc_ops shm_ops = {
729 .getnew = newseg,
730 .associate = security_shm_associate,
731 .more_checks = shm_more_checks,
732 };
733 struct ipc_params shm_params;
734
735 ns = current->nsproxy->ipc_ns;
736
737 shm_params.key = key;
738 shm_params.flg = shmflg;
739 shm_params.u.size = size;
740
741 return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
742}
743
744SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
745{
746 return ksys_shmget(key, size, shmflg);
747}
748
749static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
750{
751 switch (version) {
752 case IPC_64:
753 return copy_to_user(buf, in, sizeof(*in));
754 case IPC_OLD:
755 {
756 struct shmid_ds out;
757
758 memset(&out, 0, sizeof(out));
759 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
760 out.shm_segsz = in->shm_segsz;
761 out.shm_atime = in->shm_atime;
762 out.shm_dtime = in->shm_dtime;
763 out.shm_ctime = in->shm_ctime;
764 out.shm_cpid = in->shm_cpid;
765 out.shm_lpid = in->shm_lpid;
766 out.shm_nattch = in->shm_nattch;
767
768 return copy_to_user(buf, &out, sizeof(out));
769 }
770 default:
771 return -EINVAL;
772 }
773}
774
775static inline unsigned long
776copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
777{
778 switch (version) {
779 case IPC_64:
780 if (copy_from_user(out, buf, sizeof(*out)))
781 return -EFAULT;
782 return 0;
783 case IPC_OLD:
784 {
785 struct shmid_ds tbuf_old;
786
787 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
788 return -EFAULT;
789
790 out->shm_perm.uid = tbuf_old.shm_perm.uid;
791 out->shm_perm.gid = tbuf_old.shm_perm.gid;
792 out->shm_perm.mode = tbuf_old.shm_perm.mode;
793
794 return 0;
795 }
796 default:
797 return -EINVAL;
798 }
799}
800
801static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
802{
803 switch (version) {
804 case IPC_64:
805 return copy_to_user(buf, in, sizeof(*in));
806 case IPC_OLD:
807 {
808 struct shminfo out;
809
810 if (in->shmmax > INT_MAX)
811 out.shmmax = INT_MAX;
812 else
813 out.shmmax = (int)in->shmmax;
814
815 out.shmmin = in->shmmin;
816 out.shmmni = in->shmmni;
817 out.shmseg = in->shmseg;
818 out.shmall = in->shmall;
819
820 return copy_to_user(buf, &out, sizeof(out));
821 }
822 default:
823 return -EINVAL;
824 }
825}
826
827/*
828 * Calculate and add used RSS and swap pages of a shm.
829 * Called with shm_ids.rwsem held as a reader
830 */
831static void shm_add_rss_swap(struct shmid_kernel *shp,
832 unsigned long *rss_add, unsigned long *swp_add)
833{
834 struct inode *inode;
835
836 inode = file_inode(shp->shm_file);
837
838 if (is_file_hugepages(shp->shm_file)) {
839 struct address_space *mapping = inode->i_mapping;
840 struct hstate *h = hstate_file(shp->shm_file);
841 *rss_add += pages_per_huge_page(h) * mapping->nrpages;
842 } else {
843#ifdef CONFIG_SHMEM
844 struct shmem_inode_info *info = SHMEM_I(inode);
845
846 spin_lock_irq(&info->lock);
847 *rss_add += inode->i_mapping->nrpages;
848 *swp_add += info->swapped;
849 spin_unlock_irq(&info->lock);
850#else
851 *rss_add += inode->i_mapping->nrpages;
852#endif
853 }
854}
855
856/*
857 * Called with shm_ids.rwsem held as a reader
858 */
859static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
860 unsigned long *swp)
861{
862 int next_id;
863 int total, in_use;
864
865 *rss = 0;
866 *swp = 0;
867
868 in_use = shm_ids(ns).in_use;
869
870 for (total = 0, next_id = 0; total < in_use; next_id++) {
871 struct kern_ipc_perm *ipc;
872 struct shmid_kernel *shp;
873
874 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
875 if (ipc == NULL)
876 continue;
877 shp = container_of(ipc, struct shmid_kernel, shm_perm);
878
879 shm_add_rss_swap(shp, rss, swp);
880
881 total++;
882 }
883}
884
885/*
886 * This function handles some shmctl commands which require the rwsem
887 * to be held in write mode.
888 * NOTE: no locks must be held, the rwsem is taken inside this function.
889 */
890static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
891 struct shmid64_ds *shmid64)
892{
893 struct kern_ipc_perm *ipcp;
894 struct shmid_kernel *shp;
895 int err;
896
897 down_write(&shm_ids(ns).rwsem);
898 rcu_read_lock();
899
900 ipcp = ipcctl_obtain_check(ns, &shm_ids(ns), shmid, cmd,
901 &shmid64->shm_perm, 0);
902 if (IS_ERR(ipcp)) {
903 err = PTR_ERR(ipcp);
904 goto out_unlock1;
905 }
906
907 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
908
909 err = security_shm_shmctl(&shp->shm_perm, cmd);
910 if (err)
911 goto out_unlock1;
912
913 switch (cmd) {
914 case IPC_RMID:
915 ipc_lock_object(&shp->shm_perm);
916 /* do_shm_rmid unlocks the ipc object and rcu */
917 do_shm_rmid(ns, ipcp);
918 goto out_up;
919 case IPC_SET:
920 ipc_lock_object(&shp->shm_perm);
921 err = ipc_update_perm(&shmid64->shm_perm, ipcp);
922 if (err)
923 goto out_unlock0;
924 shp->shm_ctim = ktime_get_real_seconds();
925 break;
926 default:
927 err = -EINVAL;
928 goto out_unlock1;
929 }
930
931out_unlock0:
932 ipc_unlock_object(&shp->shm_perm);
933out_unlock1:
934 rcu_read_unlock();
935out_up:
936 up_write(&shm_ids(ns).rwsem);
937 return err;
938}
939
940static int shmctl_ipc_info(struct ipc_namespace *ns,
941 struct shminfo64 *shminfo)
942{
943 int err = security_shm_shmctl(NULL, IPC_INFO);
944 if (!err) {
945 memset(shminfo, 0, sizeof(*shminfo));
946 shminfo->shmmni = shminfo->shmseg = ns->shm_ctlmni;
947 shminfo->shmmax = ns->shm_ctlmax;
948 shminfo->shmall = ns->shm_ctlall;
949 shminfo->shmmin = SHMMIN;
950 down_read(&shm_ids(ns).rwsem);
951 err = ipc_get_maxidx(&shm_ids(ns));
952 up_read(&shm_ids(ns).rwsem);
953 if (err < 0)
954 err = 0;
955 }
956 return err;
957}
958
959static int shmctl_shm_info(struct ipc_namespace *ns,
960 struct shm_info *shm_info)
961{
962 int err = security_shm_shmctl(NULL, SHM_INFO);
963 if (!err) {
964 memset(shm_info, 0, sizeof(*shm_info));
965 down_read(&shm_ids(ns).rwsem);
966 shm_info->used_ids = shm_ids(ns).in_use;
967 shm_get_stat(ns, &shm_info->shm_rss, &shm_info->shm_swp);
968 shm_info->shm_tot = ns->shm_tot;
969 shm_info->swap_attempts = 0;
970 shm_info->swap_successes = 0;
971 err = ipc_get_maxidx(&shm_ids(ns));
972 up_read(&shm_ids(ns).rwsem);
973 if (err < 0)
974 err = 0;
975 }
976 return err;
977}
978
979static int shmctl_stat(struct ipc_namespace *ns, int shmid,
980 int cmd, struct shmid64_ds *tbuf)
981{
982 struct shmid_kernel *shp;
983 int err;
984
985 memset(tbuf, 0, sizeof(*tbuf));
986
987 rcu_read_lock();
988 if (cmd == SHM_STAT || cmd == SHM_STAT_ANY) {
989 shp = shm_obtain_object(ns, shmid);
990 if (IS_ERR(shp)) {
991 err = PTR_ERR(shp);
992 goto out_unlock;
993 }
994 } else { /* IPC_STAT */
995 shp = shm_obtain_object_check(ns, shmid);
996 if (IS_ERR(shp)) {
997 err = PTR_ERR(shp);
998 goto out_unlock;
999 }
1000 }
1001
1002 /*
1003 * Semantically SHM_STAT_ANY ought to be identical to
1004 * that functionality provided by the /proc/sysvipc/
1005 * interface. As such, only audit these calls and
1006 * do not do traditional S_IRUGO permission checks on
1007 * the ipc object.
1008 */
1009 if (cmd == SHM_STAT_ANY)
1010 audit_ipc_obj(&shp->shm_perm);
1011 else {
1012 err = -EACCES;
1013 if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
1014 goto out_unlock;
1015 }
1016
1017 err = security_shm_shmctl(&shp->shm_perm, cmd);
1018 if (err)
1019 goto out_unlock;
1020
1021 ipc_lock_object(&shp->shm_perm);
1022
1023 if (!ipc_valid_object(&shp->shm_perm)) {
1024 ipc_unlock_object(&shp->shm_perm);
1025 err = -EIDRM;
1026 goto out_unlock;
1027 }
1028
1029 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf->shm_perm);
1030 tbuf->shm_segsz = shp->shm_segsz;
1031 tbuf->shm_atime = shp->shm_atim;
1032 tbuf->shm_dtime = shp->shm_dtim;
1033 tbuf->shm_ctime = shp->shm_ctim;
1034#ifndef CONFIG_64BIT
1035 tbuf->shm_atime_high = shp->shm_atim >> 32;
1036 tbuf->shm_dtime_high = shp->shm_dtim >> 32;
1037 tbuf->shm_ctime_high = shp->shm_ctim >> 32;
1038#endif
1039 tbuf->shm_cpid = pid_vnr(shp->shm_cprid);
1040 tbuf->shm_lpid = pid_vnr(shp->shm_lprid);
1041 tbuf->shm_nattch = shp->shm_nattch;
1042
1043 if (cmd == IPC_STAT) {
1044 /*
1045 * As defined in SUS:
1046 * Return 0 on success
1047 */
1048 err = 0;
1049 } else {
1050 /*
1051 * SHM_STAT and SHM_STAT_ANY (both Linux specific)
1052 * Return the full id, including the sequence number
1053 */
1054 err = shp->shm_perm.id;
1055 }
1056
1057 ipc_unlock_object(&shp->shm_perm);
1058out_unlock:
1059 rcu_read_unlock();
1060 return err;
1061}
1062
1063static int shmctl_do_lock(struct ipc_namespace *ns, int shmid, int cmd)
1064{
1065 struct shmid_kernel *shp;
1066 struct file *shm_file;
1067 int err;
1068
1069 rcu_read_lock();
1070 shp = shm_obtain_object_check(ns, shmid);
1071 if (IS_ERR(shp)) {
1072 err = PTR_ERR(shp);
1073 goto out_unlock1;
1074 }
1075
1076 audit_ipc_obj(&(shp->shm_perm));
1077 err = security_shm_shmctl(&shp->shm_perm, cmd);
1078 if (err)
1079 goto out_unlock1;
1080
1081 ipc_lock_object(&shp->shm_perm);
1082
1083 /* check if shm_destroy() is tearing down shp */
1084 if (!ipc_valid_object(&shp->shm_perm)) {
1085 err = -EIDRM;
1086 goto out_unlock0;
1087 }
1088
1089 if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
1090 kuid_t euid = current_euid();
1091
1092 if (!uid_eq(euid, shp->shm_perm.uid) &&
1093 !uid_eq(euid, shp->shm_perm.cuid)) {
1094 err = -EPERM;
1095 goto out_unlock0;
1096 }
1097 if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) {
1098 err = -EPERM;
1099 goto out_unlock0;
1100 }
1101 }
1102
1103 shm_file = shp->shm_file;
1104 if (is_file_hugepages(shm_file))
1105 goto out_unlock0;
1106
1107 if (cmd == SHM_LOCK) {
1108 struct user_struct *user = current_user();
1109
1110 err = shmem_lock(shm_file, 1, user);
1111 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
1112 shp->shm_perm.mode |= SHM_LOCKED;
1113 shp->mlock_user = user;
1114 }
1115 goto out_unlock0;
1116 }
1117
1118 /* SHM_UNLOCK */
1119 if (!(shp->shm_perm.mode & SHM_LOCKED))
1120 goto out_unlock0;
1121 shmem_lock(shm_file, 0, shp->mlock_user);
1122 shp->shm_perm.mode &= ~SHM_LOCKED;
1123 shp->mlock_user = NULL;
1124 get_file(shm_file);
1125 ipc_unlock_object(&shp->shm_perm);
1126 rcu_read_unlock();
1127 shmem_unlock_mapping(shm_file->f_mapping);
1128
1129 fput(shm_file);
1130 return err;
1131
1132out_unlock0:
1133 ipc_unlock_object(&shp->shm_perm);
1134out_unlock1:
1135 rcu_read_unlock();
1136 return err;
1137}
1138
1139static long ksys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf, int version)
1140{
1141 int err;
1142 struct ipc_namespace *ns;
1143 struct shmid64_ds sem64;
1144
1145 if (cmd < 0 || shmid < 0)
1146 return -EINVAL;
1147
1148 ns = current->nsproxy->ipc_ns;
1149
1150 switch (cmd) {
1151 case IPC_INFO: {
1152 struct shminfo64 shminfo;
1153 err = shmctl_ipc_info(ns, &shminfo);
1154 if (err < 0)
1155 return err;
1156 if (copy_shminfo_to_user(buf, &shminfo, version))
1157 err = -EFAULT;
1158 return err;
1159 }
1160 case SHM_INFO: {
1161 struct shm_info shm_info;
1162 err = shmctl_shm_info(ns, &shm_info);
1163 if (err < 0)
1164 return err;
1165 if (copy_to_user(buf, &shm_info, sizeof(shm_info)))
1166 err = -EFAULT;
1167 return err;
1168 }
1169 case SHM_STAT:
1170 case SHM_STAT_ANY:
1171 case IPC_STAT: {
1172 err = shmctl_stat(ns, shmid, cmd, &sem64);
1173 if (err < 0)
1174 return err;
1175 if (copy_shmid_to_user(buf, &sem64, version))
1176 err = -EFAULT;
1177 return err;
1178 }
1179 case IPC_SET:
1180 if (copy_shmid_from_user(&sem64, buf, version))
1181 return -EFAULT;
1182 fallthrough;
1183 case IPC_RMID:
1184 return shmctl_down(ns, shmid, cmd, &sem64);
1185 case SHM_LOCK:
1186 case SHM_UNLOCK:
1187 return shmctl_do_lock(ns, shmid, cmd);
1188 default:
1189 return -EINVAL;
1190 }
1191}
1192
1193SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
1194{
1195 return ksys_shmctl(shmid, cmd, buf, IPC_64);
1196}
1197
1198#ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
1199long ksys_old_shmctl(int shmid, int cmd, struct shmid_ds __user *buf)
1200{
1201 int version = ipc_parse_version(&cmd);
1202
1203 return ksys_shmctl(shmid, cmd, buf, version);
1204}
1205
1206SYSCALL_DEFINE3(old_shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
1207{
1208 return ksys_old_shmctl(shmid, cmd, buf);
1209}
1210#endif
1211
1212#ifdef CONFIG_COMPAT
1213
1214struct compat_shmid_ds {
1215 struct compat_ipc_perm shm_perm;
1216 int shm_segsz;
1217 old_time32_t shm_atime;
1218 old_time32_t shm_dtime;
1219 old_time32_t shm_ctime;
1220 compat_ipc_pid_t shm_cpid;
1221 compat_ipc_pid_t shm_lpid;
1222 unsigned short shm_nattch;
1223 unsigned short shm_unused;
1224 compat_uptr_t shm_unused2;
1225 compat_uptr_t shm_unused3;
1226};
1227
1228struct compat_shminfo64 {
1229 compat_ulong_t shmmax;
1230 compat_ulong_t shmmin;
1231 compat_ulong_t shmmni;
1232 compat_ulong_t shmseg;
1233 compat_ulong_t shmall;
1234 compat_ulong_t __unused1;
1235 compat_ulong_t __unused2;
1236 compat_ulong_t __unused3;
1237 compat_ulong_t __unused4;
1238};
1239
1240struct compat_shm_info {
1241 compat_int_t used_ids;
1242 compat_ulong_t shm_tot, shm_rss, shm_swp;
1243 compat_ulong_t swap_attempts, swap_successes;
1244};
1245
1246static int copy_compat_shminfo_to_user(void __user *buf, struct shminfo64 *in,
1247 int version)
1248{
1249 if (in->shmmax > INT_MAX)
1250 in->shmmax = INT_MAX;
1251 if (version == IPC_64) {
1252 struct compat_shminfo64 info;
1253 memset(&info, 0, sizeof(info));
1254 info.shmmax = in->shmmax;
1255 info.shmmin = in->shmmin;
1256 info.shmmni = in->shmmni;
1257 info.shmseg = in->shmseg;
1258 info.shmall = in->shmall;
1259 return copy_to_user(buf, &info, sizeof(info));
1260 } else {
1261 struct shminfo info;
1262 memset(&info, 0, sizeof(info));
1263 info.shmmax = in->shmmax;
1264 info.shmmin = in->shmmin;
1265 info.shmmni = in->shmmni;
1266 info.shmseg = in->shmseg;
1267 info.shmall = in->shmall;
1268 return copy_to_user(buf, &info, sizeof(info));
1269 }
1270}
1271
1272static int put_compat_shm_info(struct shm_info *ip,
1273 struct compat_shm_info __user *uip)
1274{
1275 struct compat_shm_info info;
1276
1277 memset(&info, 0, sizeof(info));
1278 info.used_ids = ip->used_ids;
1279 info.shm_tot = ip->shm_tot;
1280 info.shm_rss = ip->shm_rss;
1281 info.shm_swp = ip->shm_swp;
1282 info.swap_attempts = ip->swap_attempts;
1283 info.swap_successes = ip->swap_successes;
1284 return copy_to_user(uip, &info, sizeof(info));
1285}
1286
1287static int copy_compat_shmid_to_user(void __user *buf, struct shmid64_ds *in,
1288 int version)
1289{
1290 if (version == IPC_64) {
1291 struct compat_shmid64_ds v;
1292 memset(&v, 0, sizeof(v));
1293 to_compat_ipc64_perm(&v.shm_perm, &in->shm_perm);
1294 v.shm_atime = lower_32_bits(in->shm_atime);
1295 v.shm_atime_high = upper_32_bits(in->shm_atime);
1296 v.shm_dtime = lower_32_bits(in->shm_dtime);
1297 v.shm_dtime_high = upper_32_bits(in->shm_dtime);
1298 v.shm_ctime = lower_32_bits(in->shm_ctime);
1299 v.shm_ctime_high = upper_32_bits(in->shm_ctime);
1300 v.shm_segsz = in->shm_segsz;
1301 v.shm_nattch = in->shm_nattch;
1302 v.shm_cpid = in->shm_cpid;
1303 v.shm_lpid = in->shm_lpid;
1304 return copy_to_user(buf, &v, sizeof(v));
1305 } else {
1306 struct compat_shmid_ds v;
1307 memset(&v, 0, sizeof(v));
1308 to_compat_ipc_perm(&v.shm_perm, &in->shm_perm);
1309 v.shm_perm.key = in->shm_perm.key;
1310 v.shm_atime = in->shm_atime;
1311 v.shm_dtime = in->shm_dtime;
1312 v.shm_ctime = in->shm_ctime;
1313 v.shm_segsz = in->shm_segsz;
1314 v.shm_nattch = in->shm_nattch;
1315 v.shm_cpid = in->shm_cpid;
1316 v.shm_lpid = in->shm_lpid;
1317 return copy_to_user(buf, &v, sizeof(v));
1318 }
1319}
1320
1321static int copy_compat_shmid_from_user(struct shmid64_ds *out, void __user *buf,
1322 int version)
1323{
1324 memset(out, 0, sizeof(*out));
1325 if (version == IPC_64) {
1326 struct compat_shmid64_ds __user *p = buf;
1327 return get_compat_ipc64_perm(&out->shm_perm, &p->shm_perm);
1328 } else {
1329 struct compat_shmid_ds __user *p = buf;
1330 return get_compat_ipc_perm(&out->shm_perm, &p->shm_perm);
1331 }
1332}
1333
1334static long compat_ksys_shmctl(int shmid, int cmd, void __user *uptr, int version)
1335{
1336 struct ipc_namespace *ns;
1337 struct shmid64_ds sem64;
1338 int err;
1339
1340 ns = current->nsproxy->ipc_ns;
1341
1342 if (cmd < 0 || shmid < 0)
1343 return -EINVAL;
1344
1345 switch (cmd) {
1346 case IPC_INFO: {
1347 struct shminfo64 shminfo;
1348 err = shmctl_ipc_info(ns, &shminfo);
1349 if (err < 0)
1350 return err;
1351 if (copy_compat_shminfo_to_user(uptr, &shminfo, version))
1352 err = -EFAULT;
1353 return err;
1354 }
1355 case SHM_INFO: {
1356 struct shm_info shm_info;
1357 err = shmctl_shm_info(ns, &shm_info);
1358 if (err < 0)
1359 return err;
1360 if (put_compat_shm_info(&shm_info, uptr))
1361 err = -EFAULT;
1362 return err;
1363 }
1364 case IPC_STAT:
1365 case SHM_STAT_ANY:
1366 case SHM_STAT:
1367 err = shmctl_stat(ns, shmid, cmd, &sem64);
1368 if (err < 0)
1369 return err;
1370 if (copy_compat_shmid_to_user(uptr, &sem64, version))
1371 err = -EFAULT;
1372 return err;
1373
1374 case IPC_SET:
1375 if (copy_compat_shmid_from_user(&sem64, uptr, version))
1376 return -EFAULT;
1377 fallthrough;
1378 case IPC_RMID:
1379 return shmctl_down(ns, shmid, cmd, &sem64);
1380 case SHM_LOCK:
1381 case SHM_UNLOCK:
1382 return shmctl_do_lock(ns, shmid, cmd);
1383 default:
1384 return -EINVAL;
1385 }
1386 return err;
1387}
1388
1389COMPAT_SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, void __user *, uptr)
1390{
1391 return compat_ksys_shmctl(shmid, cmd, uptr, IPC_64);
1392}
1393
1394#ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION
1395long compat_ksys_old_shmctl(int shmid, int cmd, void __user *uptr)
1396{
1397 int version = compat_ipc_parse_version(&cmd);
1398
1399 return compat_ksys_shmctl(shmid, cmd, uptr, version);
1400}
1401
1402COMPAT_SYSCALL_DEFINE3(old_shmctl, int, shmid, int, cmd, void __user *, uptr)
1403{
1404 return compat_ksys_old_shmctl(shmid, cmd, uptr);
1405}
1406#endif
1407#endif
1408
1409/*
1410 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
1411 *
1412 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
1413 * "raddr" thing points to kernel space, and there has to be a wrapper around
1414 * this.
1415 */
1416long do_shmat(int shmid, char __user *shmaddr, int shmflg,
1417 ulong *raddr, unsigned long shmlba)
1418{
1419 struct shmid_kernel *shp;
1420 unsigned long addr = (unsigned long)shmaddr;
1421 unsigned long size;
1422 struct file *file, *base;
1423 int err;
1424 unsigned long flags = MAP_SHARED;
1425 unsigned long prot;
1426 int acc_mode;
1427 struct ipc_namespace *ns;
1428 struct shm_file_data *sfd;
1429 int f_flags;
1430 unsigned long populate = 0;
1431
1432 err = -EINVAL;
1433 if (shmid < 0)
1434 goto out;
1435
1436 if (addr) {
1437 if (addr & (shmlba - 1)) {
1438 if (shmflg & SHM_RND) {
1439 addr &= ~(shmlba - 1); /* round down */
1440
1441 /*
1442 * Ensure that the round-down is non-nil
1443 * when remapping. This can happen for
1444 * cases when addr < shmlba.
1445 */
1446 if (!addr && (shmflg & SHM_REMAP))
1447 goto out;
1448 } else
1449#ifndef __ARCH_FORCE_SHMLBA
1450 if (addr & ~PAGE_MASK)
1451#endif
1452 goto out;
1453 }
1454
1455 flags |= MAP_FIXED;
1456 } else if ((shmflg & SHM_REMAP))
1457 goto out;
1458
1459 if (shmflg & SHM_RDONLY) {
1460 prot = PROT_READ;
1461 acc_mode = S_IRUGO;
1462 f_flags = O_RDONLY;
1463 } else {
1464 prot = PROT_READ | PROT_WRITE;
1465 acc_mode = S_IRUGO | S_IWUGO;
1466 f_flags = O_RDWR;
1467 }
1468 if (shmflg & SHM_EXEC) {
1469 prot |= PROT_EXEC;
1470 acc_mode |= S_IXUGO;
1471 }
1472
1473 /*
1474 * We cannot rely on the fs check since SYSV IPC does have an
1475 * additional creator id...
1476 */
1477 ns = current->nsproxy->ipc_ns;
1478 rcu_read_lock();
1479 shp = shm_obtain_object_check(ns, shmid);
1480 if (IS_ERR(shp)) {
1481 err = PTR_ERR(shp);
1482 goto out_unlock;
1483 }
1484
1485 err = -EACCES;
1486 if (ipcperms(ns, &shp->shm_perm, acc_mode))
1487 goto out_unlock;
1488
1489 err = security_shm_shmat(&shp->shm_perm, shmaddr, shmflg);
1490 if (err)
1491 goto out_unlock;
1492
1493 ipc_lock_object(&shp->shm_perm);
1494
1495 /* check if shm_destroy() is tearing down shp */
1496 if (!ipc_valid_object(&shp->shm_perm)) {
1497 ipc_unlock_object(&shp->shm_perm);
1498 err = -EIDRM;
1499 goto out_unlock;
1500 }
1501
1502 /*
1503 * We need to take a reference to the real shm file to prevent the
1504 * pointer from becoming stale in cases where the lifetime of the outer
1505 * file extends beyond that of the shm segment. It's not usually
1506 * possible, but it can happen during remap_file_pages() emulation as
1507 * that unmaps the memory, then does ->mmap() via file reference only.
1508 * We'll deny the ->mmap() if the shm segment was since removed, but to
1509 * detect shm ID reuse we need to compare the file pointers.
1510 */
1511 base = get_file(shp->shm_file);
1512 shp->shm_nattch++;
1513 size = i_size_read(file_inode(base));
1514 ipc_unlock_object(&shp->shm_perm);
1515 rcu_read_unlock();
1516
1517 err = -ENOMEM;
1518 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
1519 if (!sfd) {
1520 fput(base);
1521 goto out_nattch;
1522 }
1523
1524 file = alloc_file_clone(base, f_flags,
1525 is_file_hugepages(base) ?
1526 &shm_file_operations_huge :
1527 &shm_file_operations);
1528 err = PTR_ERR(file);
1529 if (IS_ERR(file)) {
1530 kfree(sfd);
1531 fput(base);
1532 goto out_nattch;
1533 }
1534
1535 sfd->id = shp->shm_perm.id;
1536 sfd->ns = get_ipc_ns(ns);
1537 sfd->file = base;
1538 sfd->vm_ops = NULL;
1539 file->private_data = sfd;
1540
1541 err = security_mmap_file(file, prot, flags);
1542 if (err)
1543 goto out_fput;
1544
1545 if (mmap_write_lock_killable(current->mm)) {
1546 err = -EINTR;
1547 goto out_fput;
1548 }
1549
1550 if (addr && !(shmflg & SHM_REMAP)) {
1551 err = -EINVAL;
1552 if (addr + size < addr)
1553 goto invalid;
1554
1555 if (find_vma_intersection(current->mm, addr, addr + size))
1556 goto invalid;
1557 }
1558
1559 addr = do_mmap(file, addr, size, prot, flags, 0, &populate, NULL);
1560 *raddr = addr;
1561 err = 0;
1562 if (IS_ERR_VALUE(addr))
1563 err = (long)addr;
1564invalid:
1565 mmap_write_unlock(current->mm);
1566 if (populate)
1567 mm_populate(addr, populate);
1568
1569out_fput:
1570 fput(file);
1571
1572out_nattch:
1573 down_write(&shm_ids(ns).rwsem);
1574 shp = shm_lock(ns, shmid);
1575 shp->shm_nattch--;
1576 if (shm_may_destroy(ns, shp))
1577 shm_destroy(ns, shp);
1578 else
1579 shm_unlock(shp);
1580 up_write(&shm_ids(ns).rwsem);
1581 return err;
1582
1583out_unlock:
1584 rcu_read_unlock();
1585out:
1586 return err;
1587}
1588
1589SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
1590{
1591 unsigned long ret;
1592 long err;
1593
1594 err = do_shmat(shmid, shmaddr, shmflg, &ret, SHMLBA);
1595 if (err)
1596 return err;
1597 force_successful_syscall_return();
1598 return (long)ret;
1599}
1600
1601#ifdef CONFIG_COMPAT
1602
1603#ifndef COMPAT_SHMLBA
1604#define COMPAT_SHMLBA SHMLBA
1605#endif
1606
1607COMPAT_SYSCALL_DEFINE3(shmat, int, shmid, compat_uptr_t, shmaddr, int, shmflg)
1608{
1609 unsigned long ret;
1610 long err;
1611
1612 err = do_shmat(shmid, compat_ptr(shmaddr), shmflg, &ret, COMPAT_SHMLBA);
1613 if (err)
1614 return err;
1615 force_successful_syscall_return();
1616 return (long)ret;
1617}
1618#endif
1619
1620/*
1621 * detach and kill segment if marked destroyed.
1622 * The work is done in shm_close.
1623 */
1624long ksys_shmdt(char __user *shmaddr)
1625{
1626 struct mm_struct *mm = current->mm;
1627 struct vm_area_struct *vma;
1628 unsigned long addr = (unsigned long)shmaddr;
1629 int retval = -EINVAL;
1630#ifdef CONFIG_MMU
1631 loff_t size = 0;
1632 struct file *file;
1633 struct vm_area_struct *next;
1634#endif
1635
1636 if (addr & ~PAGE_MASK)
1637 return retval;
1638
1639 if (mmap_write_lock_killable(mm))
1640 return -EINTR;
1641
1642 /*
1643 * This function tries to be smart and unmap shm segments that
1644 * were modified by partial mlock or munmap calls:
1645 * - It first determines the size of the shm segment that should be
1646 * unmapped: It searches for a vma that is backed by shm and that
1647 * started at address shmaddr. It records it's size and then unmaps
1648 * it.
1649 * - Then it unmaps all shm vmas that started at shmaddr and that
1650 * are within the initially determined size and that are from the
1651 * same shm segment from which we determined the size.
1652 * Errors from do_munmap are ignored: the function only fails if
1653 * it's called with invalid parameters or if it's called to unmap
1654 * a part of a vma. Both calls in this function are for full vmas,
1655 * the parameters are directly copied from the vma itself and always
1656 * valid - therefore do_munmap cannot fail. (famous last words?)
1657 */
1658 /*
1659 * If it had been mremap()'d, the starting address would not
1660 * match the usual checks anyway. So assume all vma's are
1661 * above the starting address given.
1662 */
1663 vma = find_vma(mm, addr);
1664
1665#ifdef CONFIG_MMU
1666 while (vma) {
1667 next = vma->vm_next;
1668
1669 /*
1670 * Check if the starting address would match, i.e. it's
1671 * a fragment created by mprotect() and/or munmap(), or it
1672 * otherwise it starts at this address with no hassles.
1673 */
1674 if ((vma->vm_ops == &shm_vm_ops) &&
1675 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1676
1677 /*
1678 * Record the file of the shm segment being
1679 * unmapped. With mremap(), someone could place
1680 * page from another segment but with equal offsets
1681 * in the range we are unmapping.
1682 */
1683 file = vma->vm_file;
1684 size = i_size_read(file_inode(vma->vm_file));
1685 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start, NULL);
1686 /*
1687 * We discovered the size of the shm segment, so
1688 * break out of here and fall through to the next
1689 * loop that uses the size information to stop
1690 * searching for matching vma's.
1691 */
1692 retval = 0;
1693 vma = next;
1694 break;
1695 }
1696 vma = next;
1697 }
1698
1699 /*
1700 * We need look no further than the maximum address a fragment
1701 * could possibly have landed at. Also cast things to loff_t to
1702 * prevent overflows and make comparisons vs. equal-width types.
1703 */
1704 size = PAGE_ALIGN(size);
1705 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1706 next = vma->vm_next;
1707
1708 /* finding a matching vma now does not alter retval */
1709 if ((vma->vm_ops == &shm_vm_ops) &&
1710 ((vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) &&
1711 (vma->vm_file == file))
1712 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start, NULL);
1713 vma = next;
1714 }
1715
1716#else /* CONFIG_MMU */
1717 /* under NOMMU conditions, the exact address to be destroyed must be
1718 * given
1719 */
1720 if (vma && vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1721 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start, NULL);
1722 retval = 0;
1723 }
1724
1725#endif
1726
1727 mmap_write_unlock(mm);
1728 return retval;
1729}
1730
1731SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
1732{
1733 return ksys_shmdt(shmaddr);
1734}
1735
1736#ifdef CONFIG_PROC_FS
1737static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1738{
1739 struct pid_namespace *pid_ns = ipc_seq_pid_ns(s);
1740 struct user_namespace *user_ns = seq_user_ns(s);
1741 struct kern_ipc_perm *ipcp = it;
1742 struct shmid_kernel *shp;
1743 unsigned long rss = 0, swp = 0;
1744
1745 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
1746 shm_add_rss_swap(shp, &rss, &swp);
1747
1748#if BITS_PER_LONG <= 32
1749#define SIZE_SPEC "%10lu"
1750#else
1751#define SIZE_SPEC "%21lu"
1752#endif
1753
1754 seq_printf(s,
1755 "%10d %10d %4o " SIZE_SPEC " %5u %5u "
1756 "%5lu %5u %5u %5u %5u %10llu %10llu %10llu "
1757 SIZE_SPEC " " SIZE_SPEC "\n",
1758 shp->shm_perm.key,
1759 shp->shm_perm.id,
1760 shp->shm_perm.mode,
1761 shp->shm_segsz,
1762 pid_nr_ns(shp->shm_cprid, pid_ns),
1763 pid_nr_ns(shp->shm_lprid, pid_ns),
1764 shp->shm_nattch,
1765 from_kuid_munged(user_ns, shp->shm_perm.uid),
1766 from_kgid_munged(user_ns, shp->shm_perm.gid),
1767 from_kuid_munged(user_ns, shp->shm_perm.cuid),
1768 from_kgid_munged(user_ns, shp->shm_perm.cgid),
1769 shp->shm_atim,
1770 shp->shm_dtim,
1771 shp->shm_ctim,
1772 rss * PAGE_SIZE,
1773 swp * PAGE_SIZE);
1774
1775 return 0;
1776}
1777#endif