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