Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
[platform/kernel/linux-starfive.git] / ipc / shm.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * linux/ipc/shm.c
4  * Copyright (C) 1992, 1993 Krishna Balasubramanian
5  *       Many improvements/fixes by Bruno Haible.
6  * Replaced `struct shm_desc' by `struct vm_area_struct', July 1994.
7  * Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli.
8  *
9  * /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
10  * BIGMEM support, Andrea Arcangeli <andrea@suse.de>
11  * SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr>
12  * HIGHMEM support, Ingo Molnar <mingo@redhat.com>
13  * Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <cr@sap.com>
14  * Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com>
15  * Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com>
16  *
17  * support for audit of ipc object properties and permission changes
18  * Dustin Kirkland <dustin.kirkland@us.ibm.com>
19  *
20  * namespaces support
21  * OpenVZ, SWsoft Inc.
22  * Pavel Emelianov <xemul@openvz.org>
23  *
24  * Better ipc lock (kern_ipc_perm.lock) handling
25  * Davidlohr Bueso <davidlohr.bueso@hp.com>, June 2013.
26  */
27
28 #include <linux/slab.h>
29 #include <linux/mm.h>
30 #include <linux/hugetlb.h>
31 #include <linux/shm.h>
32 #include <linux/init.h>
33 #include <linux/file.h>
34 #include <linux/mman.h>
35 #include <linux/shmem_fs.h>
36 #include <linux/security.h>
37 #include <linux/syscalls.h>
38 #include <linux/audit.h>
39 #include <linux/capability.h>
40 #include <linux/ptrace.h>
41 #include <linux/seq_file.h>
42 #include <linux/rwsem.h>
43 #include <linux/nsproxy.h>
44 #include <linux/mount.h>
45 #include <linux/ipc_namespace.h>
46 #include <linux/rhashtable.h>
47
48 #include <linux/uaccess.h>
49
50 #include "util.h"
51
52 struct shmid_kernel /* private to the kernel */
53 {
54         struct kern_ipc_perm    shm_perm;
55         struct file             *shm_file;
56         unsigned long           shm_nattch;
57         unsigned long           shm_segsz;
58         time64_t                shm_atim;
59         time64_t                shm_dtim;
60         time64_t                shm_ctim;
61         struct pid              *shm_cprid;
62         struct pid              *shm_lprid;
63         struct ucounts          *mlock_ucounts;
64
65         /*
66          * The task created the shm object, for
67          * task_lock(shp->shm_creator)
68          */
69         struct task_struct      *shm_creator;
70
71         /*
72          * List by creator. task_lock(->shm_creator) required for read/write.
73          * If list_empty(), then the creator is dead already.
74          */
75         struct list_head        shm_clist;
76         struct ipc_namespace    *ns;
77 } __randomize_layout;
78
79 /* shm_mode upper byte flags */
80 #define SHM_DEST        01000   /* segment will be destroyed on last detach */
81 #define SHM_LOCKED      02000   /* segment will not be swapped */
82
83 struct shm_file_data {
84         int id;
85         struct ipc_namespace *ns;
86         struct file *file;
87         const struct vm_operations_struct *vm_ops;
88 };
89
90 #define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
91
92 static const struct file_operations shm_file_operations;
93 static const struct vm_operations_struct shm_vm_ops;
94
95 #define shm_ids(ns)     ((ns)->ids[IPC_SHM_IDS])
96
97 #define shm_unlock(shp)                 \
98         ipc_unlock(&(shp)->shm_perm)
99
100 static int newseg(struct ipc_namespace *, struct ipc_params *);
101 static void shm_open(struct vm_area_struct *vma);
102 static void shm_close(struct vm_area_struct *vma);
103 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp);
104 #ifdef CONFIG_PROC_FS
105 static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
106 #endif
107
108 void shm_init_ns(struct ipc_namespace *ns)
109 {
110         ns->shm_ctlmax = SHMMAX;
111         ns->shm_ctlall = SHMALL;
112         ns->shm_ctlmni = SHMMNI;
113         ns->shm_rmid_forced = 0;
114         ns->shm_tot = 0;
115         ipc_init_ids(&shm_ids(ns));
116 }
117
118 /*
119  * Called with shm_ids.rwsem (writer) and the shp structure locked.
120  * Only shm_ids.rwsem remains locked on exit.
121  */
122 static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
123 {
124         struct shmid_kernel *shp;
125
126         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
127         WARN_ON(ns != shp->ns);
128
129         if (shp->shm_nattch) {
130                 shp->shm_perm.mode |= SHM_DEST;
131                 /* Do not find it any more */
132                 ipc_set_key_private(&shm_ids(ns), &shp->shm_perm);
133                 shm_unlock(shp);
134         } else
135                 shm_destroy(ns, shp);
136 }
137
138 #ifdef CONFIG_IPC_NS
139 void shm_exit_ns(struct ipc_namespace *ns)
140 {
141         free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
142         idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
143         rhashtable_destroy(&ns->ids[IPC_SHM_IDS].key_ht);
144 }
145 #endif
146
147 static int __init ipc_ns_init(void)
148 {
149         shm_init_ns(&init_ipc_ns);
150         return 0;
151 }
152
153 pure_initcall(ipc_ns_init);
154
155 void __init shm_init(void)
156 {
157         ipc_init_proc_interface("sysvipc/shm",
158 #if BITS_PER_LONG <= 32
159                                 "       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime        rss       swap\n",
160 #else
161                                 "       key      shmid perms                  size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime                   rss                  swap\n",
162 #endif
163                                 IPC_SHM_IDS, sysvipc_shm_proc_show);
164 }
165
166 static inline struct shmid_kernel *shm_obtain_object(struct ipc_namespace *ns, int id)
167 {
168         struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(&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 static inline struct shmid_kernel *shm_obtain_object_check(struct ipc_namespace *ns, int id)
177 {
178         struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&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  */
190 static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
191 {
192         struct kern_ipc_perm *ipcp;
193
194         rcu_read_lock();
195         ipcp = ipc_obtain_object_idr(&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);
213 err:
214         rcu_read_unlock();
215         /*
216          * Callers of shm_lock() must validate the status of the returned ipc
217          * object pointer and error out as appropriate.
218          */
219         return ERR_CAST(ipcp);
220 }
221
222 static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
223 {
224         rcu_read_lock();
225         ipc_lock_object(&ipcp->shm_perm);
226 }
227
228 static void shm_rcu_free(struct rcu_head *head)
229 {
230         struct kern_ipc_perm *ptr = container_of(head, struct kern_ipc_perm,
231                                                         rcu);
232         struct shmid_kernel *shp = container_of(ptr, struct shmid_kernel,
233                                                         shm_perm);
234         security_shm_free(&shp->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  */
242 static inline void shm_clist_rm(struct shmid_kernel *shp)
243 {
244         struct task_struct *creator;
245
246         /* ensure that shm_creator does not disappear */
247         rcu_read_lock();
248
249         /*
250          * A concurrent exit_shm may do a list_del_init() as well.
251          * Just do nothing if exit_shm already did the work
252          */
253         if (!list_empty(&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
271 static 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
278 static int __shm_open(struct vm_area_struct *vma)
279 {
280         struct file *file = vma->vm_file;
281         struct shm_file_data *sfd = shm_file_data(file);
282         struct shmid_kernel *shp;
283
284         shp = shm_lock(sfd->ns, sfd->id);
285
286         if (IS_ERR(shp))
287                 return PTR_ERR(shp);
288
289         if (shp->shm_file != sfd->file) {
290                 /* ID was reused */
291                 shm_unlock(shp);
292                 return -EINVAL;
293         }
294
295         shp->shm_atim = ktime_get_real_seconds();
296         ipc_update_pid(&shp->shm_lprid, task_tgid(current));
297         shp->shm_nattch++;
298         shm_unlock(shp);
299         return 0;
300 }
301
302 /* This is called by fork, once for every shm attach. */
303 static void shm_open(struct vm_area_struct *vma)
304 {
305         int err = __shm_open(vma);
306         /*
307          * We raced in the idr lookup or with shm_destroy().
308          * Either way, the ID is busted.
309          */
310         WARN_ON_ONCE(err);
311 }
312
313 /*
314  * shm_destroy - free the struct shmid_kernel
315  *
316  * @ns: namespace
317  * @shp: struct to free
318  *
319  * It has to be called with shp and shm_ids.rwsem (writer) locked,
320  * but returns with shp unlocked and freed.
321  */
322 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
323 {
324         struct file *shm_file;
325
326         shm_file = shp->shm_file;
327         shp->shm_file = NULL;
328         ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
329         shm_rmid(shp);
330         shm_unlock(shp);
331         if (!is_file_hugepages(shm_file))
332                 shmem_lock(shm_file, 0, shp->mlock_ucounts);
333         fput(shm_file);
334         ipc_update_pid(&shp->shm_cprid, NULL);
335         ipc_update_pid(&shp->shm_lprid, NULL);
336         ipc_rcu_putref(&shp->shm_perm, shm_rcu_free);
337 }
338
339 /*
340  * shm_may_destroy - identifies whether shm segment should be destroyed now
341  *
342  * Returns true if and only if there are no active users of the segment and
343  * one of the following is true:
344  *
345  * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
346  *
347  * 2) sysctl kernel.shm_rmid_forced is set to 1.
348  */
349 static bool shm_may_destroy(struct shmid_kernel *shp)
350 {
351         return (shp->shm_nattch == 0) &&
352                (shp->ns->shm_rmid_forced ||
353                 (shp->shm_perm.mode & SHM_DEST));
354 }
355
356 /*
357  * remove the attach descriptor vma.
358  * free memory for segment if it is marked destroyed.
359  * The descriptor has already been removed from the current->mm->mmap list
360  * and will later be kfree()d.
361  */
362 static void shm_close(struct vm_area_struct *vma)
363 {
364         struct file *file = vma->vm_file;
365         struct shm_file_data *sfd = shm_file_data(file);
366         struct shmid_kernel *shp;
367         struct ipc_namespace *ns = sfd->ns;
368
369         down_write(&shm_ids(ns).rwsem);
370         /* remove from the list of attaches of the shm segment */
371         shp = shm_lock(ns, sfd->id);
372
373         /*
374          * We raced in the idr lookup or with shm_destroy().
375          * Either way, the ID is busted.
376          */
377         if (WARN_ON_ONCE(IS_ERR(shp)))
378                 goto done; /* no-op */
379
380         ipc_update_pid(&shp->shm_lprid, task_tgid(current));
381         shp->shm_dtim = ktime_get_real_seconds();
382         shp->shm_nattch--;
383         if (shm_may_destroy(shp))
384                 shm_destroy(ns, shp);
385         else
386                 shm_unlock(shp);
387 done:
388         up_write(&shm_ids(ns).rwsem);
389 }
390
391 /* Called with ns->shm_ids(ns).rwsem locked */
392 static int shm_try_destroy_orphaned(int id, void *p, void *data)
393 {
394         struct ipc_namespace *ns = data;
395         struct kern_ipc_perm *ipcp = p;
396         struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
397
398         /*
399          * We want to destroy segments without users and with already
400          * exit'ed originating process.
401          *
402          * As shp->* are changed under rwsem, it's safe to skip shp locking.
403          */
404         if (!list_empty(&shp->shm_clist))
405                 return 0;
406
407         if (shm_may_destroy(shp)) {
408                 shm_lock_by_ptr(shp);
409                 shm_destroy(ns, shp);
410         }
411         return 0;
412 }
413
414 void shm_destroy_orphaned(struct ipc_namespace *ns)
415 {
416         down_write(&shm_ids(ns).rwsem);
417         if (shm_ids(ns).in_use)
418                 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
419         up_write(&shm_ids(ns).rwsem);
420 }
421
422 /* Locking assumes this will only be called with task == current */
423 void exit_shm(struct task_struct *task)
424 {
425         for (;;) {
426                 struct shmid_kernel *shp;
427                 struct ipc_namespace *ns;
428
429                 task_lock(task);
430
431                 if (list_empty(&task->sysvshm.shm_clist)) {
432                         task_unlock(task);
433                         break;
434                 }
435
436                 shp = list_first_entry(&task->sysvshm.shm_clist, struct shmid_kernel,
437                                 shm_clist);
438
439                 /*
440                  * 1) Get pointer to the ipc namespace. It is worth to say
441                  * that this pointer is guaranteed to be valid because
442                  * shp lifetime is always shorter than namespace lifetime
443                  * in which shp lives.
444                  * We taken task_lock it means that shp won't be freed.
445                  */
446                 ns = shp->ns;
447
448                 /*
449                  * 2) If kernel.shm_rmid_forced is not set then only keep track of
450                  * which shmids are orphaned, so that a later set of the sysctl
451                  * can clean them up.
452                  */
453                 if (!ns->shm_rmid_forced)
454                         goto unlink_continue;
455
456                 /*
457                  * 3) get a reference to the namespace.
458                  *    The refcount could be already 0. If it is 0, then
459                  *    the shm objects will be free by free_ipc_work().
460                  */
461                 ns = get_ipc_ns_not_zero(ns);
462                 if (!ns) {
463 unlink_continue:
464                         list_del_init(&shp->shm_clist);
465                         task_unlock(task);
466                         continue;
467                 }
468
469                 /*
470                  * 4) get a reference to shp.
471                  *   This cannot fail: shm_clist_rm() is called before
472                  *   ipc_rmid(), thus the refcount cannot be 0.
473                  */
474                 WARN_ON(!ipc_rcu_getref(&shp->shm_perm));
475
476                 /*
477                  * 5) unlink the shm segment from the list of segments
478                  *    created by current.
479                  *    This must be done last. After unlinking,
480                  *    only the refcounts obtained above prevent IPC_RMID
481                  *    from destroying the segment or the namespace.
482                  */
483                 list_del_init(&shp->shm_clist);
484
485                 task_unlock(task);
486
487                 /*
488                  * 6) we have all references
489                  *    Thus lock & if needed destroy shp.
490                  */
491                 down_write(&shm_ids(ns).rwsem);
492                 shm_lock_by_ptr(shp);
493                 /*
494                  * rcu_read_lock was implicitly taken in shm_lock_by_ptr, it's
495                  * safe to call ipc_rcu_putref here
496                  */
497                 ipc_rcu_putref(&shp->shm_perm, shm_rcu_free);
498
499                 if (ipc_valid_object(&shp->shm_perm)) {
500                         if (shm_may_destroy(shp))
501                                 shm_destroy(ns, shp);
502                         else
503                                 shm_unlock(shp);
504                 } else {
505                         /*
506                          * Someone else deleted the shp from namespace
507                          * idr/kht while we have waited.
508                          * Just unlock and continue.
509                          */
510                         shm_unlock(shp);
511                 }
512
513                 up_write(&shm_ids(ns).rwsem);
514                 put_ipc_ns(ns); /* paired with get_ipc_ns_not_zero */
515         }
516 }
517
518 static vm_fault_t shm_fault(struct vm_fault *vmf)
519 {
520         struct file *file = vmf->vma->vm_file;
521         struct shm_file_data *sfd = shm_file_data(file);
522
523         return sfd->vm_ops->fault(vmf);
524 }
525
526 static int shm_may_split(struct vm_area_struct *vma, unsigned long addr)
527 {
528         struct file *file = vma->vm_file;
529         struct shm_file_data *sfd = shm_file_data(file);
530
531         if (sfd->vm_ops->may_split)
532                 return sfd->vm_ops->may_split(vma, addr);
533
534         return 0;
535 }
536
537 static unsigned long shm_pagesize(struct vm_area_struct *vma)
538 {
539         struct file *file = vma->vm_file;
540         struct shm_file_data *sfd = shm_file_data(file);
541
542         if (sfd->vm_ops->pagesize)
543                 return sfd->vm_ops->pagesize(vma);
544
545         return PAGE_SIZE;
546 }
547
548 #ifdef CONFIG_NUMA
549 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
550 {
551         struct file *file = vma->vm_file;
552         struct shm_file_data *sfd = shm_file_data(file);
553         int err = 0;
554
555         if (sfd->vm_ops->set_policy)
556                 err = sfd->vm_ops->set_policy(vma, new);
557         return err;
558 }
559
560 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
561                                         unsigned long addr)
562 {
563         struct file *file = vma->vm_file;
564         struct shm_file_data *sfd = shm_file_data(file);
565         struct mempolicy *pol = NULL;
566
567         if (sfd->vm_ops->get_policy)
568                 pol = sfd->vm_ops->get_policy(vma, addr);
569         else if (vma->vm_policy)
570                 pol = vma->vm_policy;
571
572         return pol;
573 }
574 #endif
575
576 static int shm_mmap(struct file *file, struct vm_area_struct *vma)
577 {
578         struct shm_file_data *sfd = shm_file_data(file);
579         int ret;
580
581         /*
582          * In case of remap_file_pages() emulation, the file can represent an
583          * IPC ID that was removed, and possibly even reused by another shm
584          * segment already.  Propagate this case as an error to caller.
585          */
586         ret = __shm_open(vma);
587         if (ret)
588                 return ret;
589
590         ret = call_mmap(sfd->file, vma);
591         if (ret) {
592                 shm_close(vma);
593                 return ret;
594         }
595         sfd->vm_ops = vma->vm_ops;
596 #ifdef CONFIG_MMU
597         WARN_ON(!sfd->vm_ops->fault);
598 #endif
599         vma->vm_ops = &shm_vm_ops;
600         return 0;
601 }
602
603 static int shm_release(struct inode *ino, struct file *file)
604 {
605         struct shm_file_data *sfd = shm_file_data(file);
606
607         put_ipc_ns(sfd->ns);
608         fput(sfd->file);
609         shm_file_data(file) = NULL;
610         kfree(sfd);
611         return 0;
612 }
613
614 static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
615 {
616         struct shm_file_data *sfd = shm_file_data(file);
617
618         if (!sfd->file->f_op->fsync)
619                 return -EINVAL;
620         return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
621 }
622
623 static long shm_fallocate(struct file *file, int mode, loff_t offset,
624                           loff_t len)
625 {
626         struct shm_file_data *sfd = shm_file_data(file);
627
628         if (!sfd->file->f_op->fallocate)
629                 return -EOPNOTSUPP;
630         return sfd->file->f_op->fallocate(file, mode, offset, len);
631 }
632
633 static unsigned long shm_get_unmapped_area(struct file *file,
634         unsigned long addr, unsigned long len, unsigned long pgoff,
635         unsigned long flags)
636 {
637         struct shm_file_data *sfd = shm_file_data(file);
638
639         return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
640                                                 pgoff, flags);
641 }
642
643 static const struct file_operations shm_file_operations = {
644         .mmap           = shm_mmap,
645         .fsync          = shm_fsync,
646         .release        = shm_release,
647         .get_unmapped_area      = shm_get_unmapped_area,
648         .llseek         = noop_llseek,
649         .fallocate      = shm_fallocate,
650 };
651
652 /*
653  * shm_file_operations_huge is now identical to shm_file_operations,
654  * but we keep it distinct for the sake of is_file_shm_hugepages().
655  */
656 static const struct file_operations shm_file_operations_huge = {
657         .mmap           = shm_mmap,
658         .fsync          = shm_fsync,
659         .release        = shm_release,
660         .get_unmapped_area      = shm_get_unmapped_area,
661         .llseek         = noop_llseek,
662         .fallocate      = shm_fallocate,
663 };
664
665 bool is_file_shm_hugepages(struct file *file)
666 {
667         return file->f_op == &shm_file_operations_huge;
668 }
669
670 static const struct vm_operations_struct shm_vm_ops = {
671         .open   = shm_open,     /* callback for a new vm-area open */
672         .close  = shm_close,    /* callback for when the vm-area is released */
673         .fault  = shm_fault,
674         .may_split = shm_may_split,
675         .pagesize = shm_pagesize,
676 #if defined(CONFIG_NUMA)
677         .set_policy = shm_set_policy,
678         .get_policy = shm_get_policy,
679 #endif
680 };
681
682 /**
683  * newseg - Create a new shared memory segment
684  * @ns: namespace
685  * @params: ptr to the structure that contains key, size and shmflg
686  *
687  * Called with shm_ids.rwsem held as a writer.
688  */
689 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
690 {
691         key_t key = params->key;
692         int shmflg = params->flg;
693         size_t size = params->u.size;
694         int error;
695         struct shmid_kernel *shp;
696         size_t numpages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
697         struct file *file;
698         char name[13];
699         vm_flags_t acctflag = 0;
700
701         if (size < SHMMIN || size > ns->shm_ctlmax)
702                 return -EINVAL;
703
704         if (numpages << PAGE_SHIFT < size)
705                 return -ENOSPC;
706
707         if (ns->shm_tot + numpages < ns->shm_tot ||
708                         ns->shm_tot + numpages > ns->shm_ctlall)
709                 return -ENOSPC;
710
711         shp = kmalloc(sizeof(*shp), GFP_KERNEL_ACCOUNT);
712         if (unlikely(!shp))
713                 return -ENOMEM;
714
715         shp->shm_perm.key = key;
716         shp->shm_perm.mode = (shmflg & S_IRWXUGO);
717         shp->mlock_ucounts = NULL;
718
719         shp->shm_perm.security = NULL;
720         error = security_shm_alloc(&shp->shm_perm);
721         if (error) {
722                 kfree(shp);
723                 return error;
724         }
725
726         sprintf(name, "SYSV%08x", key);
727         if (shmflg & SHM_HUGETLB) {
728                 struct hstate *hs;
729                 size_t hugesize;
730
731                 hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
732                 if (!hs) {
733                         error = -EINVAL;
734                         goto no_file;
735                 }
736                 hugesize = ALIGN(size, huge_page_size(hs));
737
738                 /* hugetlb_file_setup applies strict accounting */
739                 if (shmflg & SHM_NORESERVE)
740                         acctflag = VM_NORESERVE;
741                 file = hugetlb_file_setup(name, hugesize, acctflag,
742                                 HUGETLB_SHMFS_INODE, (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
743         } else {
744                 /*
745                  * Do not allow no accounting for OVERCOMMIT_NEVER, even
746                  * if it's asked for.
747                  */
748                 if  ((shmflg & SHM_NORESERVE) &&
749                                 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
750                         acctflag = VM_NORESERVE;
751                 file = shmem_kernel_file_setup(name, size, acctflag);
752         }
753         error = PTR_ERR(file);
754         if (IS_ERR(file))
755                 goto no_file;
756
757         shp->shm_cprid = get_pid(task_tgid(current));
758         shp->shm_lprid = NULL;
759         shp->shm_atim = shp->shm_dtim = 0;
760         shp->shm_ctim = ktime_get_real_seconds();
761         shp->shm_segsz = size;
762         shp->shm_nattch = 0;
763         shp->shm_file = file;
764         shp->shm_creator = current;
765
766         /* ipc_addid() locks shp upon success. */
767         error = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
768         if (error < 0)
769                 goto no_id;
770
771         shp->ns = ns;
772
773         task_lock(current);
774         list_add(&shp->shm_clist, &current->sysvshm.shm_clist);
775         task_unlock(current);
776
777         /*
778          * shmid gets reported as "inode#" in /proc/pid/maps.
779          * proc-ps tools use this. Changing this will break them.
780          */
781         file_inode(file)->i_ino = shp->shm_perm.id;
782
783         ns->shm_tot += numpages;
784         error = shp->shm_perm.id;
785
786         ipc_unlock_object(&shp->shm_perm);
787         rcu_read_unlock();
788         return error;
789
790 no_id:
791         ipc_update_pid(&shp->shm_cprid, NULL);
792         ipc_update_pid(&shp->shm_lprid, NULL);
793         fput(file);
794         ipc_rcu_putref(&shp->shm_perm, shm_rcu_free);
795         return error;
796 no_file:
797         call_rcu(&shp->shm_perm.rcu, shm_rcu_free);
798         return error;
799 }
800
801 /*
802  * Called with shm_ids.rwsem and ipcp locked.
803  */
804 static int shm_more_checks(struct kern_ipc_perm *ipcp, struct ipc_params *params)
805 {
806         struct shmid_kernel *shp;
807
808         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
809         if (shp->shm_segsz < params->u.size)
810                 return -EINVAL;
811
812         return 0;
813 }
814
815 long ksys_shmget(key_t key, size_t size, int shmflg)
816 {
817         struct ipc_namespace *ns;
818         static const struct ipc_ops shm_ops = {
819                 .getnew = newseg,
820                 .associate = security_shm_associate,
821                 .more_checks = shm_more_checks,
822         };
823         struct ipc_params shm_params;
824
825         ns = current->nsproxy->ipc_ns;
826
827         shm_params.key = key;
828         shm_params.flg = shmflg;
829         shm_params.u.size = size;
830
831         return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
832 }
833
834 SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
835 {
836         return ksys_shmget(key, size, shmflg);
837 }
838
839 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
840 {
841         switch (version) {
842         case IPC_64:
843                 return copy_to_user(buf, in, sizeof(*in));
844         case IPC_OLD:
845             {
846                 struct shmid_ds out;
847
848                 memset(&out, 0, sizeof(out));
849                 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
850                 out.shm_segsz   = in->shm_segsz;
851                 out.shm_atime   = in->shm_atime;
852                 out.shm_dtime   = in->shm_dtime;
853                 out.shm_ctime   = in->shm_ctime;
854                 out.shm_cpid    = in->shm_cpid;
855                 out.shm_lpid    = in->shm_lpid;
856                 out.shm_nattch  = in->shm_nattch;
857
858                 return copy_to_user(buf, &out, sizeof(out));
859             }
860         default:
861                 return -EINVAL;
862         }
863 }
864
865 static inline unsigned long
866 copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
867 {
868         switch (version) {
869         case IPC_64:
870                 if (copy_from_user(out, buf, sizeof(*out)))
871                         return -EFAULT;
872                 return 0;
873         case IPC_OLD:
874             {
875                 struct shmid_ds tbuf_old;
876
877                 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
878                         return -EFAULT;
879
880                 out->shm_perm.uid       = tbuf_old.shm_perm.uid;
881                 out->shm_perm.gid       = tbuf_old.shm_perm.gid;
882                 out->shm_perm.mode      = tbuf_old.shm_perm.mode;
883
884                 return 0;
885             }
886         default:
887                 return -EINVAL;
888         }
889 }
890
891 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
892 {
893         switch (version) {
894         case IPC_64:
895                 return copy_to_user(buf, in, sizeof(*in));
896         case IPC_OLD:
897             {
898                 struct shminfo out;
899
900                 if (in->shmmax > INT_MAX)
901                         out.shmmax = INT_MAX;
902                 else
903                         out.shmmax = (int)in->shmmax;
904
905                 out.shmmin      = in->shmmin;
906                 out.shmmni      = in->shmmni;
907                 out.shmseg      = in->shmseg;
908                 out.shmall      = in->shmall;
909
910                 return copy_to_user(buf, &out, sizeof(out));
911             }
912         default:
913                 return -EINVAL;
914         }
915 }
916
917 /*
918  * Calculate and add used RSS and swap pages of a shm.
919  * Called with shm_ids.rwsem held as a reader
920  */
921 static void shm_add_rss_swap(struct shmid_kernel *shp,
922         unsigned long *rss_add, unsigned long *swp_add)
923 {
924         struct inode *inode;
925
926         inode = file_inode(shp->shm_file);
927
928         if (is_file_hugepages(shp->shm_file)) {
929                 struct address_space *mapping = inode->i_mapping;
930                 struct hstate *h = hstate_file(shp->shm_file);
931                 *rss_add += pages_per_huge_page(h) * mapping->nrpages;
932         } else {
933 #ifdef CONFIG_SHMEM
934                 struct shmem_inode_info *info = SHMEM_I(inode);
935
936                 spin_lock_irq(&info->lock);
937                 *rss_add += inode->i_mapping->nrpages;
938                 *swp_add += info->swapped;
939                 spin_unlock_irq(&info->lock);
940 #else
941                 *rss_add += inode->i_mapping->nrpages;
942 #endif
943         }
944 }
945
946 /*
947  * Called with shm_ids.rwsem held as a reader
948  */
949 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
950                 unsigned long *swp)
951 {
952         int next_id;
953         int total, in_use;
954
955         *rss = 0;
956         *swp = 0;
957
958         in_use = shm_ids(ns).in_use;
959
960         for (total = 0, next_id = 0; total < in_use; next_id++) {
961                 struct kern_ipc_perm *ipc;
962                 struct shmid_kernel *shp;
963
964                 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
965                 if (ipc == NULL)
966                         continue;
967                 shp = container_of(ipc, struct shmid_kernel, shm_perm);
968
969                 shm_add_rss_swap(shp, rss, swp);
970
971                 total++;
972         }
973 }
974
975 /*
976  * This function handles some shmctl commands which require the rwsem
977  * to be held in write mode.
978  * NOTE: no locks must be held, the rwsem is taken inside this function.
979  */
980 static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
981                        struct shmid64_ds *shmid64)
982 {
983         struct kern_ipc_perm *ipcp;
984         struct shmid_kernel *shp;
985         int err;
986
987         down_write(&shm_ids(ns).rwsem);
988         rcu_read_lock();
989
990         ipcp = ipcctl_obtain_check(ns, &shm_ids(ns), shmid, cmd,
991                                       &shmid64->shm_perm, 0);
992         if (IS_ERR(ipcp)) {
993                 err = PTR_ERR(ipcp);
994                 goto out_unlock1;
995         }
996
997         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
998
999         err = security_shm_shmctl(&shp->shm_perm, cmd);
1000         if (err)
1001                 goto out_unlock1;
1002
1003         switch (cmd) {
1004         case IPC_RMID:
1005                 ipc_lock_object(&shp->shm_perm);
1006                 /* do_shm_rmid unlocks the ipc object and rcu */
1007                 do_shm_rmid(ns, ipcp);
1008                 goto out_up;
1009         case IPC_SET:
1010                 ipc_lock_object(&shp->shm_perm);
1011                 err = ipc_update_perm(&shmid64->shm_perm, ipcp);
1012                 if (err)
1013                         goto out_unlock0;
1014                 shp->shm_ctim = ktime_get_real_seconds();
1015                 break;
1016         default:
1017                 err = -EINVAL;
1018                 goto out_unlock1;
1019         }
1020
1021 out_unlock0:
1022         ipc_unlock_object(&shp->shm_perm);
1023 out_unlock1:
1024         rcu_read_unlock();
1025 out_up:
1026         up_write(&shm_ids(ns).rwsem);
1027         return err;
1028 }
1029
1030 static int shmctl_ipc_info(struct ipc_namespace *ns,
1031                            struct shminfo64 *shminfo)
1032 {
1033         int err = security_shm_shmctl(NULL, IPC_INFO);
1034         if (!err) {
1035                 memset(shminfo, 0, sizeof(*shminfo));
1036                 shminfo->shmmni = shminfo->shmseg = ns->shm_ctlmni;
1037                 shminfo->shmmax = ns->shm_ctlmax;
1038                 shminfo->shmall = ns->shm_ctlall;
1039                 shminfo->shmmin = SHMMIN;
1040                 down_read(&shm_ids(ns).rwsem);
1041                 err = ipc_get_maxidx(&shm_ids(ns));
1042                 up_read(&shm_ids(ns).rwsem);
1043                 if (err < 0)
1044                         err = 0;
1045         }
1046         return err;
1047 }
1048
1049 static int shmctl_shm_info(struct ipc_namespace *ns,
1050                            struct shm_info *shm_info)
1051 {
1052         int err = security_shm_shmctl(NULL, SHM_INFO);
1053         if (!err) {
1054                 memset(shm_info, 0, sizeof(*shm_info));
1055                 down_read(&shm_ids(ns).rwsem);
1056                 shm_info->used_ids = shm_ids(ns).in_use;
1057                 shm_get_stat(ns, &shm_info->shm_rss, &shm_info->shm_swp);
1058                 shm_info->shm_tot = ns->shm_tot;
1059                 shm_info->swap_attempts = 0;
1060                 shm_info->swap_successes = 0;
1061                 err = ipc_get_maxidx(&shm_ids(ns));
1062                 up_read(&shm_ids(ns).rwsem);
1063                 if (err < 0)
1064                         err = 0;
1065         }
1066         return err;
1067 }
1068
1069 static int shmctl_stat(struct ipc_namespace *ns, int shmid,
1070                         int cmd, struct shmid64_ds *tbuf)
1071 {
1072         struct shmid_kernel *shp;
1073         int err;
1074
1075         memset(tbuf, 0, sizeof(*tbuf));
1076
1077         rcu_read_lock();
1078         if (cmd == SHM_STAT || cmd == SHM_STAT_ANY) {
1079                 shp = shm_obtain_object(ns, shmid);
1080                 if (IS_ERR(shp)) {
1081                         err = PTR_ERR(shp);
1082                         goto out_unlock;
1083                 }
1084         } else { /* IPC_STAT */
1085                 shp = shm_obtain_object_check(ns, shmid);
1086                 if (IS_ERR(shp)) {
1087                         err = PTR_ERR(shp);
1088                         goto out_unlock;
1089                 }
1090         }
1091
1092         /*
1093          * Semantically SHM_STAT_ANY ought to be identical to
1094          * that functionality provided by the /proc/sysvipc/
1095          * interface. As such, only audit these calls and
1096          * do not do traditional S_IRUGO permission checks on
1097          * the ipc object.
1098          */
1099         if (cmd == SHM_STAT_ANY)
1100                 audit_ipc_obj(&shp->shm_perm);
1101         else {
1102                 err = -EACCES;
1103                 if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
1104                         goto out_unlock;
1105         }
1106
1107         err = security_shm_shmctl(&shp->shm_perm, cmd);
1108         if (err)
1109                 goto out_unlock;
1110
1111         ipc_lock_object(&shp->shm_perm);
1112
1113         if (!ipc_valid_object(&shp->shm_perm)) {
1114                 ipc_unlock_object(&shp->shm_perm);
1115                 err = -EIDRM;
1116                 goto out_unlock;
1117         }
1118
1119         kernel_to_ipc64_perm(&shp->shm_perm, &tbuf->shm_perm);
1120         tbuf->shm_segsz = shp->shm_segsz;
1121         tbuf->shm_atime = shp->shm_atim;
1122         tbuf->shm_dtime = shp->shm_dtim;
1123         tbuf->shm_ctime = shp->shm_ctim;
1124 #ifndef CONFIG_64BIT
1125         tbuf->shm_atime_high = shp->shm_atim >> 32;
1126         tbuf->shm_dtime_high = shp->shm_dtim >> 32;
1127         tbuf->shm_ctime_high = shp->shm_ctim >> 32;
1128 #endif
1129         tbuf->shm_cpid  = pid_vnr(shp->shm_cprid);
1130         tbuf->shm_lpid  = pid_vnr(shp->shm_lprid);
1131         tbuf->shm_nattch = shp->shm_nattch;
1132
1133         if (cmd == IPC_STAT) {
1134                 /*
1135                  * As defined in SUS:
1136                  * Return 0 on success
1137                  */
1138                 err = 0;
1139         } else {
1140                 /*
1141                  * SHM_STAT and SHM_STAT_ANY (both Linux specific)
1142                  * Return the full id, including the sequence number
1143                  */
1144                 err = shp->shm_perm.id;
1145         }
1146
1147         ipc_unlock_object(&shp->shm_perm);
1148 out_unlock:
1149         rcu_read_unlock();
1150         return err;
1151 }
1152
1153 static int shmctl_do_lock(struct ipc_namespace *ns, int shmid, int cmd)
1154 {
1155         struct shmid_kernel *shp;
1156         struct file *shm_file;
1157         int err;
1158
1159         rcu_read_lock();
1160         shp = shm_obtain_object_check(ns, shmid);
1161         if (IS_ERR(shp)) {
1162                 err = PTR_ERR(shp);
1163                 goto out_unlock1;
1164         }
1165
1166         audit_ipc_obj(&(shp->shm_perm));
1167         err = security_shm_shmctl(&shp->shm_perm, cmd);
1168         if (err)
1169                 goto out_unlock1;
1170
1171         ipc_lock_object(&shp->shm_perm);
1172
1173         /* check if shm_destroy() is tearing down shp */
1174         if (!ipc_valid_object(&shp->shm_perm)) {
1175                 err = -EIDRM;
1176                 goto out_unlock0;
1177         }
1178
1179         if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
1180                 kuid_t euid = current_euid();
1181
1182                 if (!uid_eq(euid, shp->shm_perm.uid) &&
1183                     !uid_eq(euid, shp->shm_perm.cuid)) {
1184                         err = -EPERM;
1185                         goto out_unlock0;
1186                 }
1187                 if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) {
1188                         err = -EPERM;
1189                         goto out_unlock0;
1190                 }
1191         }
1192
1193         shm_file = shp->shm_file;
1194         if (is_file_hugepages(shm_file))
1195                 goto out_unlock0;
1196
1197         if (cmd == SHM_LOCK) {
1198                 struct ucounts *ucounts = current_ucounts();
1199
1200                 err = shmem_lock(shm_file, 1, ucounts);
1201                 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
1202                         shp->shm_perm.mode |= SHM_LOCKED;
1203                         shp->mlock_ucounts = ucounts;
1204                 }
1205                 goto out_unlock0;
1206         }
1207
1208         /* SHM_UNLOCK */
1209         if (!(shp->shm_perm.mode & SHM_LOCKED))
1210                 goto out_unlock0;
1211         shmem_lock(shm_file, 0, shp->mlock_ucounts);
1212         shp->shm_perm.mode &= ~SHM_LOCKED;
1213         shp->mlock_ucounts = NULL;
1214         get_file(shm_file);
1215         ipc_unlock_object(&shp->shm_perm);
1216         rcu_read_unlock();
1217         shmem_unlock_mapping(shm_file->f_mapping);
1218
1219         fput(shm_file);
1220         return err;
1221
1222 out_unlock0:
1223         ipc_unlock_object(&shp->shm_perm);
1224 out_unlock1:
1225         rcu_read_unlock();
1226         return err;
1227 }
1228
1229 static long ksys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf, int version)
1230 {
1231         int err;
1232         struct ipc_namespace *ns;
1233         struct shmid64_ds sem64;
1234
1235         if (cmd < 0 || shmid < 0)
1236                 return -EINVAL;
1237
1238         ns = current->nsproxy->ipc_ns;
1239
1240         switch (cmd) {
1241         case IPC_INFO: {
1242                 struct shminfo64 shminfo;
1243                 err = shmctl_ipc_info(ns, &shminfo);
1244                 if (err < 0)
1245                         return err;
1246                 if (copy_shminfo_to_user(buf, &shminfo, version))
1247                         err = -EFAULT;
1248                 return err;
1249         }
1250         case SHM_INFO: {
1251                 struct shm_info shm_info;
1252                 err = shmctl_shm_info(ns, &shm_info);
1253                 if (err < 0)
1254                         return err;
1255                 if (copy_to_user(buf, &shm_info, sizeof(shm_info)))
1256                         err = -EFAULT;
1257                 return err;
1258         }
1259         case SHM_STAT:
1260         case SHM_STAT_ANY:
1261         case IPC_STAT: {
1262                 err = shmctl_stat(ns, shmid, cmd, &sem64);
1263                 if (err < 0)
1264                         return err;
1265                 if (copy_shmid_to_user(buf, &sem64, version))
1266                         err = -EFAULT;
1267                 return err;
1268         }
1269         case IPC_SET:
1270                 if (copy_shmid_from_user(&sem64, buf, version))
1271                         return -EFAULT;
1272                 fallthrough;
1273         case IPC_RMID:
1274                 return shmctl_down(ns, shmid, cmd, &sem64);
1275         case SHM_LOCK:
1276         case SHM_UNLOCK:
1277                 return shmctl_do_lock(ns, shmid, cmd);
1278         default:
1279                 return -EINVAL;
1280         }
1281 }
1282
1283 SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
1284 {
1285         return ksys_shmctl(shmid, cmd, buf, IPC_64);
1286 }
1287
1288 #ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
1289 long ksys_old_shmctl(int shmid, int cmd, struct shmid_ds __user *buf)
1290 {
1291         int version = ipc_parse_version(&cmd);
1292
1293         return ksys_shmctl(shmid, cmd, buf, version);
1294 }
1295
1296 SYSCALL_DEFINE3(old_shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
1297 {
1298         return ksys_old_shmctl(shmid, cmd, buf);
1299 }
1300 #endif
1301
1302 #ifdef CONFIG_COMPAT
1303
1304 struct compat_shmid_ds {
1305         struct compat_ipc_perm shm_perm;
1306         int shm_segsz;
1307         old_time32_t shm_atime;
1308         old_time32_t shm_dtime;
1309         old_time32_t shm_ctime;
1310         compat_ipc_pid_t shm_cpid;
1311         compat_ipc_pid_t shm_lpid;
1312         unsigned short shm_nattch;
1313         unsigned short shm_unused;
1314         compat_uptr_t shm_unused2;
1315         compat_uptr_t shm_unused3;
1316 };
1317
1318 struct compat_shminfo64 {
1319         compat_ulong_t shmmax;
1320         compat_ulong_t shmmin;
1321         compat_ulong_t shmmni;
1322         compat_ulong_t shmseg;
1323         compat_ulong_t shmall;
1324         compat_ulong_t __unused1;
1325         compat_ulong_t __unused2;
1326         compat_ulong_t __unused3;
1327         compat_ulong_t __unused4;
1328 };
1329
1330 struct compat_shm_info {
1331         compat_int_t used_ids;
1332         compat_ulong_t shm_tot, shm_rss, shm_swp;
1333         compat_ulong_t swap_attempts, swap_successes;
1334 };
1335
1336 static int copy_compat_shminfo_to_user(void __user *buf, struct shminfo64 *in,
1337                                         int version)
1338 {
1339         if (in->shmmax > INT_MAX)
1340                 in->shmmax = INT_MAX;
1341         if (version == IPC_64) {
1342                 struct compat_shminfo64 info;
1343                 memset(&info, 0, sizeof(info));
1344                 info.shmmax = in->shmmax;
1345                 info.shmmin = in->shmmin;
1346                 info.shmmni = in->shmmni;
1347                 info.shmseg = in->shmseg;
1348                 info.shmall = in->shmall;
1349                 return copy_to_user(buf, &info, sizeof(info));
1350         } else {
1351                 struct shminfo info;
1352                 memset(&info, 0, sizeof(info));
1353                 info.shmmax = in->shmmax;
1354                 info.shmmin = in->shmmin;
1355                 info.shmmni = in->shmmni;
1356                 info.shmseg = in->shmseg;
1357                 info.shmall = in->shmall;
1358                 return copy_to_user(buf, &info, sizeof(info));
1359         }
1360 }
1361
1362 static int put_compat_shm_info(struct shm_info *ip,
1363                                 struct compat_shm_info __user *uip)
1364 {
1365         struct compat_shm_info info;
1366
1367         memset(&info, 0, sizeof(info));
1368         info.used_ids = ip->used_ids;
1369         info.shm_tot = ip->shm_tot;
1370         info.shm_rss = ip->shm_rss;
1371         info.shm_swp = ip->shm_swp;
1372         info.swap_attempts = ip->swap_attempts;
1373         info.swap_successes = ip->swap_successes;
1374         return copy_to_user(uip, &info, sizeof(info));
1375 }
1376
1377 static int copy_compat_shmid_to_user(void __user *buf, struct shmid64_ds *in,
1378                                         int version)
1379 {
1380         if (version == IPC_64) {
1381                 struct compat_shmid64_ds v;
1382                 memset(&v, 0, sizeof(v));
1383                 to_compat_ipc64_perm(&v.shm_perm, &in->shm_perm);
1384                 v.shm_atime      = lower_32_bits(in->shm_atime);
1385                 v.shm_atime_high = upper_32_bits(in->shm_atime);
1386                 v.shm_dtime      = lower_32_bits(in->shm_dtime);
1387                 v.shm_dtime_high = upper_32_bits(in->shm_dtime);
1388                 v.shm_ctime      = lower_32_bits(in->shm_ctime);
1389                 v.shm_ctime_high = upper_32_bits(in->shm_ctime);
1390                 v.shm_segsz = in->shm_segsz;
1391                 v.shm_nattch = in->shm_nattch;
1392                 v.shm_cpid = in->shm_cpid;
1393                 v.shm_lpid = in->shm_lpid;
1394                 return copy_to_user(buf, &v, sizeof(v));
1395         } else {
1396                 struct compat_shmid_ds v;
1397                 memset(&v, 0, sizeof(v));
1398                 to_compat_ipc_perm(&v.shm_perm, &in->shm_perm);
1399                 v.shm_perm.key = in->shm_perm.key;
1400                 v.shm_atime = in->shm_atime;
1401                 v.shm_dtime = in->shm_dtime;
1402                 v.shm_ctime = in->shm_ctime;
1403                 v.shm_segsz = in->shm_segsz;
1404                 v.shm_nattch = in->shm_nattch;
1405                 v.shm_cpid = in->shm_cpid;
1406                 v.shm_lpid = in->shm_lpid;
1407                 return copy_to_user(buf, &v, sizeof(v));
1408         }
1409 }
1410
1411 static int copy_compat_shmid_from_user(struct shmid64_ds *out, void __user *buf,
1412                                         int version)
1413 {
1414         memset(out, 0, sizeof(*out));
1415         if (version == IPC_64) {
1416                 struct compat_shmid64_ds __user *p = buf;
1417                 return get_compat_ipc64_perm(&out->shm_perm, &p->shm_perm);
1418         } else {
1419                 struct compat_shmid_ds __user *p = buf;
1420                 return get_compat_ipc_perm(&out->shm_perm, &p->shm_perm);
1421         }
1422 }
1423
1424 static long compat_ksys_shmctl(int shmid, int cmd, void __user *uptr, int version)
1425 {
1426         struct ipc_namespace *ns;
1427         struct shmid64_ds sem64;
1428         int err;
1429
1430         ns = current->nsproxy->ipc_ns;
1431
1432         if (cmd < 0 || shmid < 0)
1433                 return -EINVAL;
1434
1435         switch (cmd) {
1436         case IPC_INFO: {
1437                 struct shminfo64 shminfo;
1438                 err = shmctl_ipc_info(ns, &shminfo);
1439                 if (err < 0)
1440                         return err;
1441                 if (copy_compat_shminfo_to_user(uptr, &shminfo, version))
1442                         err = -EFAULT;
1443                 return err;
1444         }
1445         case SHM_INFO: {
1446                 struct shm_info shm_info;
1447                 err = shmctl_shm_info(ns, &shm_info);
1448                 if (err < 0)
1449                         return err;
1450                 if (put_compat_shm_info(&shm_info, uptr))
1451                         err = -EFAULT;
1452                 return err;
1453         }
1454         case IPC_STAT:
1455         case SHM_STAT_ANY:
1456         case SHM_STAT:
1457                 err = shmctl_stat(ns, shmid, cmd, &sem64);
1458                 if (err < 0)
1459                         return err;
1460                 if (copy_compat_shmid_to_user(uptr, &sem64, version))
1461                         err = -EFAULT;
1462                 return err;
1463
1464         case IPC_SET:
1465                 if (copy_compat_shmid_from_user(&sem64, uptr, version))
1466                         return -EFAULT;
1467                 fallthrough;
1468         case IPC_RMID:
1469                 return shmctl_down(ns, shmid, cmd, &sem64);
1470         case SHM_LOCK:
1471         case SHM_UNLOCK:
1472                 return shmctl_do_lock(ns, shmid, cmd);
1473         default:
1474                 return -EINVAL;
1475         }
1476         return err;
1477 }
1478
1479 COMPAT_SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, void __user *, uptr)
1480 {
1481         return compat_ksys_shmctl(shmid, cmd, uptr, IPC_64);
1482 }
1483
1484 #ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION
1485 long compat_ksys_old_shmctl(int shmid, int cmd, void __user *uptr)
1486 {
1487         int version = compat_ipc_parse_version(&cmd);
1488
1489         return compat_ksys_shmctl(shmid, cmd, uptr, version);
1490 }
1491
1492 COMPAT_SYSCALL_DEFINE3(old_shmctl, int, shmid, int, cmd, void __user *, uptr)
1493 {
1494         return compat_ksys_old_shmctl(shmid, cmd, uptr);
1495 }
1496 #endif
1497 #endif
1498
1499 /*
1500  * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
1501  *
1502  * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
1503  * "raddr" thing points to kernel space, and there has to be a wrapper around
1504  * this.
1505  */
1506 long do_shmat(int shmid, char __user *shmaddr, int shmflg,
1507               ulong *raddr, unsigned long shmlba)
1508 {
1509         struct shmid_kernel *shp;
1510         unsigned long addr = (unsigned long)shmaddr;
1511         unsigned long size;
1512         struct file *file, *base;
1513         int    err;
1514         unsigned long flags = MAP_SHARED;
1515         unsigned long prot;
1516         int acc_mode;
1517         struct ipc_namespace *ns;
1518         struct shm_file_data *sfd;
1519         int f_flags;
1520         unsigned long populate = 0;
1521
1522         err = -EINVAL;
1523         if (shmid < 0)
1524                 goto out;
1525
1526         if (addr) {
1527                 if (addr & (shmlba - 1)) {
1528                         if (shmflg & SHM_RND) {
1529                                 addr &= ~(shmlba - 1);  /* round down */
1530
1531                                 /*
1532                                  * Ensure that the round-down is non-nil
1533                                  * when remapping. This can happen for
1534                                  * cases when addr < shmlba.
1535                                  */
1536                                 if (!addr && (shmflg & SHM_REMAP))
1537                                         goto out;
1538                         } else
1539 #ifndef __ARCH_FORCE_SHMLBA
1540                                 if (addr & ~PAGE_MASK)
1541 #endif
1542                                         goto out;
1543                 }
1544
1545                 flags |= MAP_FIXED;
1546         } else if ((shmflg & SHM_REMAP))
1547                 goto out;
1548
1549         if (shmflg & SHM_RDONLY) {
1550                 prot = PROT_READ;
1551                 acc_mode = S_IRUGO;
1552                 f_flags = O_RDONLY;
1553         } else {
1554                 prot = PROT_READ | PROT_WRITE;
1555                 acc_mode = S_IRUGO | S_IWUGO;
1556                 f_flags = O_RDWR;
1557         }
1558         if (shmflg & SHM_EXEC) {
1559                 prot |= PROT_EXEC;
1560                 acc_mode |= S_IXUGO;
1561         }
1562
1563         /*
1564          * We cannot rely on the fs check since SYSV IPC does have an
1565          * additional creator id...
1566          */
1567         ns = current->nsproxy->ipc_ns;
1568         rcu_read_lock();
1569         shp = shm_obtain_object_check(ns, shmid);
1570         if (IS_ERR(shp)) {
1571                 err = PTR_ERR(shp);
1572                 goto out_unlock;
1573         }
1574
1575         err = -EACCES;
1576         if (ipcperms(ns, &shp->shm_perm, acc_mode))
1577                 goto out_unlock;
1578
1579         err = security_shm_shmat(&shp->shm_perm, shmaddr, shmflg);
1580         if (err)
1581                 goto out_unlock;
1582
1583         ipc_lock_object(&shp->shm_perm);
1584
1585         /* check if shm_destroy() is tearing down shp */
1586         if (!ipc_valid_object(&shp->shm_perm)) {
1587                 ipc_unlock_object(&shp->shm_perm);
1588                 err = -EIDRM;
1589                 goto out_unlock;
1590         }
1591
1592         /*
1593          * We need to take a reference to the real shm file to prevent the
1594          * pointer from becoming stale in cases where the lifetime of the outer
1595          * file extends beyond that of the shm segment.  It's not usually
1596          * possible, but it can happen during remap_file_pages() emulation as
1597          * that unmaps the memory, then does ->mmap() via file reference only.
1598          * We'll deny the ->mmap() if the shm segment was since removed, but to
1599          * detect shm ID reuse we need to compare the file pointers.
1600          */
1601         base = get_file(shp->shm_file);
1602         shp->shm_nattch++;
1603         size = i_size_read(file_inode(base));
1604         ipc_unlock_object(&shp->shm_perm);
1605         rcu_read_unlock();
1606
1607         err = -ENOMEM;
1608         sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
1609         if (!sfd) {
1610                 fput(base);
1611                 goto out_nattch;
1612         }
1613
1614         file = alloc_file_clone(base, f_flags,
1615                           is_file_hugepages(base) ?
1616                                 &shm_file_operations_huge :
1617                                 &shm_file_operations);
1618         err = PTR_ERR(file);
1619         if (IS_ERR(file)) {
1620                 kfree(sfd);
1621                 fput(base);
1622                 goto out_nattch;
1623         }
1624
1625         sfd->id = shp->shm_perm.id;
1626         sfd->ns = get_ipc_ns(ns);
1627         sfd->file = base;
1628         sfd->vm_ops = NULL;
1629         file->private_data = sfd;
1630
1631         err = security_mmap_file(file, prot, flags);
1632         if (err)
1633                 goto out_fput;
1634
1635         if (mmap_write_lock_killable(current->mm)) {
1636                 err = -EINTR;
1637                 goto out_fput;
1638         }
1639
1640         if (addr && !(shmflg & SHM_REMAP)) {
1641                 err = -EINVAL;
1642                 if (addr + size < addr)
1643                         goto invalid;
1644
1645                 if (find_vma_intersection(current->mm, addr, addr + size))
1646                         goto invalid;
1647         }
1648
1649         addr = do_mmap(file, addr, size, prot, flags, 0, &populate, NULL);
1650         *raddr = addr;
1651         err = 0;
1652         if (IS_ERR_VALUE(addr))
1653                 err = (long)addr;
1654 invalid:
1655         mmap_write_unlock(current->mm);
1656         if (populate)
1657                 mm_populate(addr, populate);
1658
1659 out_fput:
1660         fput(file);
1661
1662 out_nattch:
1663         down_write(&shm_ids(ns).rwsem);
1664         shp = shm_lock(ns, shmid);
1665         shp->shm_nattch--;
1666
1667         if (shm_may_destroy(shp))
1668                 shm_destroy(ns, shp);
1669         else
1670                 shm_unlock(shp);
1671         up_write(&shm_ids(ns).rwsem);
1672         return err;
1673
1674 out_unlock:
1675         rcu_read_unlock();
1676 out:
1677         return err;
1678 }
1679
1680 SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
1681 {
1682         unsigned long ret;
1683         long err;
1684
1685         err = do_shmat(shmid, shmaddr, shmflg, &ret, SHMLBA);
1686         if (err)
1687                 return err;
1688         force_successful_syscall_return();
1689         return (long)ret;
1690 }
1691
1692 #ifdef CONFIG_COMPAT
1693
1694 #ifndef COMPAT_SHMLBA
1695 #define COMPAT_SHMLBA   SHMLBA
1696 #endif
1697
1698 COMPAT_SYSCALL_DEFINE3(shmat, int, shmid, compat_uptr_t, shmaddr, int, shmflg)
1699 {
1700         unsigned long ret;
1701         long err;
1702
1703         err = do_shmat(shmid, compat_ptr(shmaddr), shmflg, &ret, COMPAT_SHMLBA);
1704         if (err)
1705                 return err;
1706         force_successful_syscall_return();
1707         return (long)ret;
1708 }
1709 #endif
1710
1711 /*
1712  * detach and kill segment if marked destroyed.
1713  * The work is done in shm_close.
1714  */
1715 long ksys_shmdt(char __user *shmaddr)
1716 {
1717         struct mm_struct *mm = current->mm;
1718         struct vm_area_struct *vma;
1719         unsigned long addr = (unsigned long)shmaddr;
1720         int retval = -EINVAL;
1721 #ifdef CONFIG_MMU
1722         loff_t size = 0;
1723         struct file *file;
1724         struct vm_area_struct *next;
1725 #endif
1726
1727         if (addr & ~PAGE_MASK)
1728                 return retval;
1729
1730         if (mmap_write_lock_killable(mm))
1731                 return -EINTR;
1732
1733         /*
1734          * This function tries to be smart and unmap shm segments that
1735          * were modified by partial mlock or munmap calls:
1736          * - It first determines the size of the shm segment that should be
1737          *   unmapped: It searches for a vma that is backed by shm and that
1738          *   started at address shmaddr. It records it's size and then unmaps
1739          *   it.
1740          * - Then it unmaps all shm vmas that started at shmaddr and that
1741          *   are within the initially determined size and that are from the
1742          *   same shm segment from which we determined the size.
1743          * Errors from do_munmap are ignored: the function only fails if
1744          * it's called with invalid parameters or if it's called to unmap
1745          * a part of a vma. Both calls in this function are for full vmas,
1746          * the parameters are directly copied from the vma itself and always
1747          * valid - therefore do_munmap cannot fail. (famous last words?)
1748          */
1749         /*
1750          * If it had been mremap()'d, the starting address would not
1751          * match the usual checks anyway. So assume all vma's are
1752          * above the starting address given.
1753          */
1754         vma = find_vma(mm, addr);
1755
1756 #ifdef CONFIG_MMU
1757         while (vma) {
1758                 next = vma->vm_next;
1759
1760                 /*
1761                  * Check if the starting address would match, i.e. it's
1762                  * a fragment created by mprotect() and/or munmap(), or it
1763                  * otherwise it starts at this address with no hassles.
1764                  */
1765                 if ((vma->vm_ops == &shm_vm_ops) &&
1766                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1767
1768                         /*
1769                          * Record the file of the shm segment being
1770                          * unmapped.  With mremap(), someone could place
1771                          * page from another segment but with equal offsets
1772                          * in the range we are unmapping.
1773                          */
1774                         file = vma->vm_file;
1775                         size = i_size_read(file_inode(vma->vm_file));
1776                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start, NULL);
1777                         /*
1778                          * We discovered the size of the shm segment, so
1779                          * break out of here and fall through to the next
1780                          * loop that uses the size information to stop
1781                          * searching for matching vma's.
1782                          */
1783                         retval = 0;
1784                         vma = next;
1785                         break;
1786                 }
1787                 vma = next;
1788         }
1789
1790         /*
1791          * We need look no further than the maximum address a fragment
1792          * could possibly have landed at. Also cast things to loff_t to
1793          * prevent overflows and make comparisons vs. equal-width types.
1794          */
1795         size = PAGE_ALIGN(size);
1796         while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1797                 next = vma->vm_next;
1798
1799                 /* finding a matching vma now does not alter retval */
1800                 if ((vma->vm_ops == &shm_vm_ops) &&
1801                     ((vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) &&
1802                     (vma->vm_file == file))
1803                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start, NULL);
1804                 vma = next;
1805         }
1806
1807 #else   /* CONFIG_MMU */
1808         /* under NOMMU conditions, the exact address to be destroyed must be
1809          * given
1810          */
1811         if (vma && vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1812                 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start, NULL);
1813                 retval = 0;
1814         }
1815
1816 #endif
1817
1818         mmap_write_unlock(mm);
1819         return retval;
1820 }
1821
1822 SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
1823 {
1824         return ksys_shmdt(shmaddr);
1825 }
1826
1827 #ifdef CONFIG_PROC_FS
1828 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1829 {
1830         struct pid_namespace *pid_ns = ipc_seq_pid_ns(s);
1831         struct user_namespace *user_ns = seq_user_ns(s);
1832         struct kern_ipc_perm *ipcp = it;
1833         struct shmid_kernel *shp;
1834         unsigned long rss = 0, swp = 0;
1835
1836         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
1837         shm_add_rss_swap(shp, &rss, &swp);
1838
1839 #if BITS_PER_LONG <= 32
1840 #define SIZE_SPEC "%10lu"
1841 #else
1842 #define SIZE_SPEC "%21lu"
1843 #endif
1844
1845         seq_printf(s,
1846                    "%10d %10d  %4o " SIZE_SPEC " %5u %5u  "
1847                    "%5lu %5u %5u %5u %5u %10llu %10llu %10llu "
1848                    SIZE_SPEC " " SIZE_SPEC "\n",
1849                    shp->shm_perm.key,
1850                    shp->shm_perm.id,
1851                    shp->shm_perm.mode,
1852                    shp->shm_segsz,
1853                    pid_nr_ns(shp->shm_cprid, pid_ns),
1854                    pid_nr_ns(shp->shm_lprid, pid_ns),
1855                    shp->shm_nattch,
1856                    from_kuid_munged(user_ns, shp->shm_perm.uid),
1857                    from_kgid_munged(user_ns, shp->shm_perm.gid),
1858                    from_kuid_munged(user_ns, shp->shm_perm.cuid),
1859                    from_kgid_munged(user_ns, shp->shm_perm.cgid),
1860                    shp->shm_atim,
1861                    shp->shm_dtim,
1862                    shp->shm_ctim,
1863                    rss * PAGE_SIZE,
1864                    swp * PAGE_SIZE);
1865
1866         return 0;
1867 }
1868 #endif