Merge branch 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa...
[platform/adaptation/renesas_rcar/renesas_kernel.git] / ipc / shm.c
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  * Better ipc lock (kern_ipc_perm.lock) handling
24  * Davidlohr Bueso <davidlohr.bueso@hp.com>, June 2013.
25  */
26
27 #include <linux/slab.h>
28 #include <linux/mm.h>
29 #include <linux/hugetlb.h>
30 #include <linux/shm.h>
31 #include <linux/init.h>
32 #include <linux/file.h>
33 #include <linux/mman.h>
34 #include <linux/shmem_fs.h>
35 #include <linux/security.h>
36 #include <linux/syscalls.h>
37 #include <linux/audit.h>
38 #include <linux/capability.h>
39 #include <linux/ptrace.h>
40 #include <linux/seq_file.h>
41 #include <linux/rwsem.h>
42 #include <linux/nsproxy.h>
43 #include <linux/mount.h>
44 #include <linux/ipc_namespace.h>
45
46 #include <asm/uaccess.h>
47
48 #include "util.h"
49
50 struct shm_file_data {
51         int id;
52         struct ipc_namespace *ns;
53         struct file *file;
54         const struct vm_operations_struct *vm_ops;
55 };
56
57 #define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
58
59 static const struct file_operations shm_file_operations;
60 static const struct vm_operations_struct shm_vm_ops;
61
62 #define shm_ids(ns)     ((ns)->ids[IPC_SHM_IDS])
63
64 #define shm_unlock(shp)                 \
65         ipc_unlock(&(shp)->shm_perm)
66
67 static int newseg(struct ipc_namespace *, struct ipc_params *);
68 static void shm_open(struct vm_area_struct *vma);
69 static void shm_close(struct vm_area_struct *vma);
70 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp);
71 #ifdef CONFIG_PROC_FS
72 static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
73 #endif
74
75 void shm_init_ns(struct ipc_namespace *ns)
76 {
77         ns->shm_ctlmax = SHMMAX;
78         ns->shm_ctlall = SHMALL;
79         ns->shm_ctlmni = SHMMNI;
80         ns->shm_rmid_forced = 0;
81         ns->shm_tot = 0;
82         ipc_init_ids(&shm_ids(ns));
83 }
84
85 /*
86  * Called with shm_ids.rwsem (writer) and the shp structure locked.
87  * Only shm_ids.rwsem remains locked on exit.
88  */
89 static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
90 {
91         struct shmid_kernel *shp;
92         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
93
94         if (shp->shm_nattch) {
95                 shp->shm_perm.mode |= SHM_DEST;
96                 /* Do not find it any more */
97                 shp->shm_perm.key = IPC_PRIVATE;
98                 shm_unlock(shp);
99         } else
100                 shm_destroy(ns, shp);
101 }
102
103 #ifdef CONFIG_IPC_NS
104 void shm_exit_ns(struct ipc_namespace *ns)
105 {
106         free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
107         idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
108 }
109 #endif
110
111 static int __init ipc_ns_init(void)
112 {
113         shm_init_ns(&init_ipc_ns);
114         return 0;
115 }
116
117 pure_initcall(ipc_ns_init);
118
119 void __init shm_init(void)
120 {
121         ipc_init_proc_interface("sysvipc/shm",
122 #if BITS_PER_LONG <= 32
123                                 "       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime        rss       swap\n",
124 #else
125                                 "       key      shmid perms                  size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime                   rss                  swap\n",
126 #endif
127                                 IPC_SHM_IDS, sysvipc_shm_proc_show);
128 }
129
130 static inline struct shmid_kernel *shm_obtain_object(struct ipc_namespace *ns, int id)
131 {
132         struct kern_ipc_perm *ipcp = ipc_obtain_object(&shm_ids(ns), id);
133
134         if (IS_ERR(ipcp))
135                 return ERR_CAST(ipcp);
136
137         return container_of(ipcp, struct shmid_kernel, shm_perm);
138 }
139
140 static inline struct shmid_kernel *shm_obtain_object_check(struct ipc_namespace *ns, int id)
141 {
142         struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&shm_ids(ns), id);
143
144         if (IS_ERR(ipcp))
145                 return ERR_CAST(ipcp);
146
147         return container_of(ipcp, struct shmid_kernel, shm_perm);
148 }
149
150 /*
151  * shm_lock_(check_) routines are called in the paths where the rwsem
152  * is not necessarily held.
153  */
154 static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
155 {
156         struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
157
158         if (IS_ERR(ipcp))
159                 return (struct shmid_kernel *)ipcp;
160
161         return container_of(ipcp, struct shmid_kernel, shm_perm);
162 }
163
164 static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
165 {
166         rcu_read_lock();
167         ipc_lock_object(&ipcp->shm_perm);
168 }
169
170 static void shm_rcu_free(struct rcu_head *head)
171 {
172         struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu);
173         struct shmid_kernel *shp = ipc_rcu_to_struct(p);
174
175         security_shm_free(shp);
176         ipc_rcu_free(head);
177 }
178
179 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
180 {
181         ipc_rmid(&shm_ids(ns), &s->shm_perm);
182 }
183
184
185 /* This is called by fork, once for every shm attach. */
186 static void shm_open(struct vm_area_struct *vma)
187 {
188         struct file *file = vma->vm_file;
189         struct shm_file_data *sfd = shm_file_data(file);
190         struct shmid_kernel *shp;
191
192         shp = shm_lock(sfd->ns, sfd->id);
193         BUG_ON(IS_ERR(shp));
194         shp->shm_atim = get_seconds();
195         shp->shm_lprid = task_tgid_vnr(current);
196         shp->shm_nattch++;
197         shm_unlock(shp);
198 }
199
200 /*
201  * shm_destroy - free the struct shmid_kernel
202  *
203  * @ns: namespace
204  * @shp: struct to free
205  *
206  * It has to be called with shp and shm_ids.rwsem (writer) locked,
207  * but returns with shp unlocked and freed.
208  */
209 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
210 {
211         struct file *shm_file;
212
213         shm_file = shp->shm_file;
214         shp->shm_file = NULL;
215         ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
216         shm_rmid(ns, shp);
217         shm_unlock(shp);
218         if (!is_file_hugepages(shm_file))
219                 shmem_lock(shm_file, 0, shp->mlock_user);
220         else if (shp->mlock_user)
221                 user_shm_unlock(file_inode(shm_file)->i_size, shp->mlock_user);
222         fput(shm_file);
223         ipc_rcu_putref(shp, shm_rcu_free);
224 }
225
226 /*
227  * shm_may_destroy - identifies whether shm segment should be destroyed now
228  *
229  * Returns true if and only if there are no active users of the segment and
230  * one of the following is true:
231  *
232  * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
233  *
234  * 2) sysctl kernel.shm_rmid_forced is set to 1.
235  */
236 static bool shm_may_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
237 {
238         return (shp->shm_nattch == 0) &&
239                (ns->shm_rmid_forced ||
240                 (shp->shm_perm.mode & SHM_DEST));
241 }
242
243 /*
244  * remove the attach descriptor vma.
245  * free memory for segment if it is marked destroyed.
246  * The descriptor has already been removed from the current->mm->mmap list
247  * and will later be kfree()d.
248  */
249 static void shm_close(struct vm_area_struct *vma)
250 {
251         struct file *file = vma->vm_file;
252         struct shm_file_data *sfd = shm_file_data(file);
253         struct shmid_kernel *shp;
254         struct ipc_namespace *ns = sfd->ns;
255
256         down_write(&shm_ids(ns).rwsem);
257         /* remove from the list of attaches of the shm segment */
258         shp = shm_lock(ns, sfd->id);
259         BUG_ON(IS_ERR(shp));
260         shp->shm_lprid = task_tgid_vnr(current);
261         shp->shm_dtim = get_seconds();
262         shp->shm_nattch--;
263         if (shm_may_destroy(ns, shp))
264                 shm_destroy(ns, shp);
265         else
266                 shm_unlock(shp);
267         up_write(&shm_ids(ns).rwsem);
268 }
269
270 /* Called with ns->shm_ids(ns).rwsem locked */
271 static int shm_try_destroy_current(int id, void *p, void *data)
272 {
273         struct ipc_namespace *ns = data;
274         struct kern_ipc_perm *ipcp = p;
275         struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
276
277         if (shp->shm_creator != current)
278                 return 0;
279
280         /*
281          * Mark it as orphaned to destroy the segment when
282          * kernel.shm_rmid_forced is changed.
283          * It is noop if the following shm_may_destroy() returns true.
284          */
285         shp->shm_creator = NULL;
286
287         /*
288          * Don't even try to destroy it.  If shm_rmid_forced=0 and IPC_RMID
289          * is not set, it shouldn't be deleted here.
290          */
291         if (!ns->shm_rmid_forced)
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
301 /* Called with ns->shm_ids(ns).rwsem locked */
302 static int shm_try_destroy_orphaned(int id, void *p, void *data)
303 {
304         struct ipc_namespace *ns = data;
305         struct kern_ipc_perm *ipcp = p;
306         struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
307
308         /*
309          * We want to destroy segments without users and with already
310          * exit'ed originating process.
311          *
312          * As shp->* are changed under rwsem, it's safe to skip shp locking.
313          */
314         if (shp->shm_creator != NULL)
315                 return 0;
316
317         if (shm_may_destroy(ns, shp)) {
318                 shm_lock_by_ptr(shp);
319                 shm_destroy(ns, shp);
320         }
321         return 0;
322 }
323
324 void shm_destroy_orphaned(struct ipc_namespace *ns)
325 {
326         down_write(&shm_ids(ns).rwsem);
327         if (shm_ids(ns).in_use)
328                 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
329         up_write(&shm_ids(ns).rwsem);
330 }
331
332
333 void exit_shm(struct task_struct *task)
334 {
335         struct ipc_namespace *ns = task->nsproxy->ipc_ns;
336
337         if (shm_ids(ns).in_use == 0)
338                 return;
339
340         /* Destroy all already created segments, but not mapped yet */
341         down_write(&shm_ids(ns).rwsem);
342         if (shm_ids(ns).in_use)
343                 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_current, ns);
344         up_write(&shm_ids(ns).rwsem);
345 }
346
347 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
348 {
349         struct file *file = vma->vm_file;
350         struct shm_file_data *sfd = shm_file_data(file);
351
352         return sfd->vm_ops->fault(vma, vmf);
353 }
354
355 #ifdef CONFIG_NUMA
356 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
357 {
358         struct file *file = vma->vm_file;
359         struct shm_file_data *sfd = shm_file_data(file);
360         int err = 0;
361         if (sfd->vm_ops->set_policy)
362                 err = sfd->vm_ops->set_policy(vma, new);
363         return err;
364 }
365
366 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
367                                         unsigned long addr)
368 {
369         struct file *file = vma->vm_file;
370         struct shm_file_data *sfd = shm_file_data(file);
371         struct mempolicy *pol = NULL;
372
373         if (sfd->vm_ops->get_policy)
374                 pol = sfd->vm_ops->get_policy(vma, addr);
375         else if (vma->vm_policy)
376                 pol = vma->vm_policy;
377
378         return pol;
379 }
380 #endif
381
382 static int shm_mmap(struct file *file, struct vm_area_struct *vma)
383 {
384         struct shm_file_data *sfd = shm_file_data(file);
385         int ret;
386
387         ret = sfd->file->f_op->mmap(sfd->file, vma);
388         if (ret != 0)
389                 return ret;
390         sfd->vm_ops = vma->vm_ops;
391 #ifdef CONFIG_MMU
392         BUG_ON(!sfd->vm_ops->fault);
393 #endif
394         vma->vm_ops = &shm_vm_ops;
395         shm_open(vma);
396
397         return ret;
398 }
399
400 static int shm_release(struct inode *ino, struct file *file)
401 {
402         struct shm_file_data *sfd = shm_file_data(file);
403
404         put_ipc_ns(sfd->ns);
405         shm_file_data(file) = NULL;
406         kfree(sfd);
407         return 0;
408 }
409
410 static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
411 {
412         struct shm_file_data *sfd = shm_file_data(file);
413
414         if (!sfd->file->f_op->fsync)
415                 return -EINVAL;
416         return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
417 }
418
419 static long shm_fallocate(struct file *file, int mode, loff_t offset,
420                           loff_t len)
421 {
422         struct shm_file_data *sfd = shm_file_data(file);
423
424         if (!sfd->file->f_op->fallocate)
425                 return -EOPNOTSUPP;
426         return sfd->file->f_op->fallocate(file, mode, offset, len);
427 }
428
429 static unsigned long shm_get_unmapped_area(struct file *file,
430         unsigned long addr, unsigned long len, unsigned long pgoff,
431         unsigned long flags)
432 {
433         struct shm_file_data *sfd = shm_file_data(file);
434         return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
435                                                 pgoff, flags);
436 }
437
438 static const struct file_operations shm_file_operations = {
439         .mmap           = shm_mmap,
440         .fsync          = shm_fsync,
441         .release        = shm_release,
442 #ifndef CONFIG_MMU
443         .get_unmapped_area      = shm_get_unmapped_area,
444 #endif
445         .llseek         = noop_llseek,
446         .fallocate      = shm_fallocate,
447 };
448
449 static const struct file_operations shm_file_operations_huge = {
450         .mmap           = shm_mmap,
451         .fsync          = shm_fsync,
452         .release        = shm_release,
453         .get_unmapped_area      = shm_get_unmapped_area,
454         .llseek         = noop_llseek,
455         .fallocate      = shm_fallocate,
456 };
457
458 int is_file_shm_hugepages(struct file *file)
459 {
460         return file->f_op == &shm_file_operations_huge;
461 }
462
463 static const struct vm_operations_struct shm_vm_ops = {
464         .open   = shm_open,     /* callback for a new vm-area open */
465         .close  = shm_close,    /* callback for when the vm-area is released */
466         .fault  = shm_fault,
467 #if defined(CONFIG_NUMA)
468         .set_policy = shm_set_policy,
469         .get_policy = shm_get_policy,
470 #endif
471 };
472
473 /**
474  * newseg - Create a new shared memory segment
475  * @ns: namespace
476  * @params: ptr to the structure that contains key, size and shmflg
477  *
478  * Called with shm_ids.rwsem held as a writer.
479  */
480 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
481 {
482         key_t key = params->key;
483         int shmflg = params->flg;
484         size_t size = params->u.size;
485         int error;
486         struct shmid_kernel *shp;
487         size_t numpages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
488         struct file *file;
489         char name[13];
490         int id;
491         vm_flags_t acctflag = 0;
492
493         if (size < SHMMIN || size > ns->shm_ctlmax)
494                 return -EINVAL;
495
496         if (ns->shm_tot + numpages > ns->shm_ctlall)
497                 return -ENOSPC;
498
499         shp = ipc_rcu_alloc(sizeof(*shp));
500         if (!shp)
501                 return -ENOMEM;
502
503         shp->shm_perm.key = key;
504         shp->shm_perm.mode = (shmflg & S_IRWXUGO);
505         shp->mlock_user = NULL;
506
507         shp->shm_perm.security = NULL;
508         error = security_shm_alloc(shp);
509         if (error) {
510                 ipc_rcu_putref(shp, ipc_rcu_free);
511                 return error;
512         }
513
514         sprintf(name, "SYSV%08x", key);
515         if (shmflg & SHM_HUGETLB) {
516                 struct hstate *hs;
517                 size_t hugesize;
518
519                 hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
520                 if (!hs) {
521                         error = -EINVAL;
522                         goto no_file;
523                 }
524                 hugesize = ALIGN(size, huge_page_size(hs));
525
526                 /* hugetlb_file_setup applies strict accounting */
527                 if (shmflg & SHM_NORESERVE)
528                         acctflag = VM_NORESERVE;
529                 file = hugetlb_file_setup(name, hugesize, acctflag,
530                                   &shp->mlock_user, HUGETLB_SHMFS_INODE,
531                                 (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
532         } else {
533                 /*
534                  * Do not allow no accounting for OVERCOMMIT_NEVER, even
535                  * if it's asked for.
536                  */
537                 if  ((shmflg & SHM_NORESERVE) &&
538                                 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
539                         acctflag = VM_NORESERVE;
540                 file = shmem_file_setup(name, size, acctflag);
541         }
542         error = PTR_ERR(file);
543         if (IS_ERR(file))
544                 goto no_file;
545
546         id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
547         if (id < 0) {
548                 error = id;
549                 goto no_id;
550         }
551
552         shp->shm_cprid = task_tgid_vnr(current);
553         shp->shm_lprid = 0;
554         shp->shm_atim = shp->shm_dtim = 0;
555         shp->shm_ctim = get_seconds();
556         shp->shm_segsz = size;
557         shp->shm_nattch = 0;
558         shp->shm_file = file;
559         shp->shm_creator = current;
560
561         /*
562          * shmid gets reported as "inode#" in /proc/pid/maps.
563          * proc-ps tools use this. Changing this will break them.
564          */
565         file_inode(file)->i_ino = shp->shm_perm.id;
566
567         ns->shm_tot += numpages;
568         error = shp->shm_perm.id;
569
570         ipc_unlock_object(&shp->shm_perm);
571         rcu_read_unlock();
572         return error;
573
574 no_id:
575         if (is_file_hugepages(file) && shp->mlock_user)
576                 user_shm_unlock(size, shp->mlock_user);
577         fput(file);
578 no_file:
579         ipc_rcu_putref(shp, shm_rcu_free);
580         return error;
581 }
582
583 /*
584  * Called with shm_ids.rwsem and ipcp locked.
585  */
586 static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
587 {
588         struct shmid_kernel *shp;
589
590         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
591         return security_shm_associate(shp, shmflg);
592 }
593
594 /*
595  * Called with shm_ids.rwsem and ipcp locked.
596  */
597 static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
598                                 struct ipc_params *params)
599 {
600         struct shmid_kernel *shp;
601
602         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
603         if (shp->shm_segsz < params->u.size)
604                 return -EINVAL;
605
606         return 0;
607 }
608
609 SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
610 {
611         struct ipc_namespace *ns;
612         struct ipc_ops shm_ops;
613         struct ipc_params shm_params;
614
615         ns = current->nsproxy->ipc_ns;
616
617         shm_ops.getnew = newseg;
618         shm_ops.associate = shm_security;
619         shm_ops.more_checks = shm_more_checks;
620
621         shm_params.key = key;
622         shm_params.flg = shmflg;
623         shm_params.u.size = size;
624
625         return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
626 }
627
628 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
629 {
630         switch (version) {
631         case IPC_64:
632                 return copy_to_user(buf, in, sizeof(*in));
633         case IPC_OLD:
634             {
635                 struct shmid_ds out;
636
637                 memset(&out, 0, sizeof(out));
638                 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
639                 out.shm_segsz   = in->shm_segsz;
640                 out.shm_atime   = in->shm_atime;
641                 out.shm_dtime   = in->shm_dtime;
642                 out.shm_ctime   = in->shm_ctime;
643                 out.shm_cpid    = in->shm_cpid;
644                 out.shm_lpid    = in->shm_lpid;
645                 out.shm_nattch  = in->shm_nattch;
646
647                 return copy_to_user(buf, &out, sizeof(out));
648             }
649         default:
650                 return -EINVAL;
651         }
652 }
653
654 static inline unsigned long
655 copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
656 {
657         switch (version) {
658         case IPC_64:
659                 if (copy_from_user(out, buf, sizeof(*out)))
660                         return -EFAULT;
661                 return 0;
662         case IPC_OLD:
663             {
664                 struct shmid_ds tbuf_old;
665
666                 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
667                         return -EFAULT;
668
669                 out->shm_perm.uid       = tbuf_old.shm_perm.uid;
670                 out->shm_perm.gid       = tbuf_old.shm_perm.gid;
671                 out->shm_perm.mode      = tbuf_old.shm_perm.mode;
672
673                 return 0;
674             }
675         default:
676                 return -EINVAL;
677         }
678 }
679
680 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
681 {
682         switch (version) {
683         case IPC_64:
684                 return copy_to_user(buf, in, sizeof(*in));
685         case IPC_OLD:
686             {
687                 struct shminfo out;
688
689                 if (in->shmmax > INT_MAX)
690                         out.shmmax = INT_MAX;
691                 else
692                         out.shmmax = (int)in->shmmax;
693
694                 out.shmmin      = in->shmmin;
695                 out.shmmni      = in->shmmni;
696                 out.shmseg      = in->shmseg;
697                 out.shmall      = in->shmall; 
698
699                 return copy_to_user(buf, &out, sizeof(out));
700             }
701         default:
702                 return -EINVAL;
703         }
704 }
705
706 /*
707  * Calculate and add used RSS and swap pages of a shm.
708  * Called with shm_ids.rwsem held as a reader
709  */
710 static void shm_add_rss_swap(struct shmid_kernel *shp,
711         unsigned long *rss_add, unsigned long *swp_add)
712 {
713         struct inode *inode;
714
715         inode = file_inode(shp->shm_file);
716
717         if (is_file_hugepages(shp->shm_file)) {
718                 struct address_space *mapping = inode->i_mapping;
719                 struct hstate *h = hstate_file(shp->shm_file);
720                 *rss_add += pages_per_huge_page(h) * mapping->nrpages;
721         } else {
722 #ifdef CONFIG_SHMEM
723                 struct shmem_inode_info *info = SHMEM_I(inode);
724                 spin_lock(&info->lock);
725                 *rss_add += inode->i_mapping->nrpages;
726                 *swp_add += info->swapped;
727                 spin_unlock(&info->lock);
728 #else
729                 *rss_add += inode->i_mapping->nrpages;
730 #endif
731         }
732 }
733
734 /*
735  * Called with shm_ids.rwsem held as a reader
736  */
737 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
738                 unsigned long *swp)
739 {
740         int next_id;
741         int total, in_use;
742
743         *rss = 0;
744         *swp = 0;
745
746         in_use = shm_ids(ns).in_use;
747
748         for (total = 0, next_id = 0; total < in_use; next_id++) {
749                 struct kern_ipc_perm *ipc;
750                 struct shmid_kernel *shp;
751
752                 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
753                 if (ipc == NULL)
754                         continue;
755                 shp = container_of(ipc, struct shmid_kernel, shm_perm);
756
757                 shm_add_rss_swap(shp, rss, swp);
758
759                 total++;
760         }
761 }
762
763 /*
764  * This function handles some shmctl commands which require the rwsem
765  * to be held in write mode.
766  * NOTE: no locks must be held, the rwsem is taken inside this function.
767  */
768 static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
769                        struct shmid_ds __user *buf, int version)
770 {
771         struct kern_ipc_perm *ipcp;
772         struct shmid64_ds shmid64;
773         struct shmid_kernel *shp;
774         int err;
775
776         if (cmd == IPC_SET) {
777                 if (copy_shmid_from_user(&shmid64, buf, version))
778                         return -EFAULT;
779         }
780
781         down_write(&shm_ids(ns).rwsem);
782         rcu_read_lock();
783
784         ipcp = ipcctl_pre_down_nolock(ns, &shm_ids(ns), shmid, cmd,
785                                       &shmid64.shm_perm, 0);
786         if (IS_ERR(ipcp)) {
787                 err = PTR_ERR(ipcp);
788                 goto out_unlock1;
789         }
790
791         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
792
793         err = security_shm_shmctl(shp, cmd);
794         if (err)
795                 goto out_unlock1;
796
797         switch (cmd) {
798         case IPC_RMID:
799                 ipc_lock_object(&shp->shm_perm);
800                 /* do_shm_rmid unlocks the ipc object and rcu */
801                 do_shm_rmid(ns, ipcp);
802                 goto out_up;
803         case IPC_SET:
804                 ipc_lock_object(&shp->shm_perm);
805                 err = ipc_update_perm(&shmid64.shm_perm, ipcp);
806                 if (err)
807                         goto out_unlock0;
808                 shp->shm_ctim = get_seconds();
809                 break;
810         default:
811                 err = -EINVAL;
812                 goto out_unlock1;
813         }
814
815 out_unlock0:
816         ipc_unlock_object(&shp->shm_perm);
817 out_unlock1:
818         rcu_read_unlock();
819 out_up:
820         up_write(&shm_ids(ns).rwsem);
821         return err;
822 }
823
824 static int shmctl_nolock(struct ipc_namespace *ns, int shmid,
825                          int cmd, int version, void __user *buf)
826 {
827         int err;
828         struct shmid_kernel *shp;
829
830         /* preliminary security checks for *_INFO */
831         if (cmd == IPC_INFO || cmd == SHM_INFO) {
832                 err = security_shm_shmctl(NULL, cmd);
833                 if (err)
834                         return err;
835         }
836
837         switch (cmd) {
838         case IPC_INFO:
839         {
840                 struct shminfo64 shminfo;
841
842                 memset(&shminfo, 0, sizeof(shminfo));
843                 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
844                 shminfo.shmmax = ns->shm_ctlmax;
845                 shminfo.shmall = ns->shm_ctlall;
846
847                 shminfo.shmmin = SHMMIN;
848                 if (copy_shminfo_to_user(buf, &shminfo, version))
849                         return -EFAULT;
850
851                 down_read(&shm_ids(ns).rwsem);
852                 err = ipc_get_maxid(&shm_ids(ns));
853                 up_read(&shm_ids(ns).rwsem);
854
855                 if (err < 0)
856                         err = 0;
857                 goto out;
858         }
859         case SHM_INFO:
860         {
861                 struct shm_info shm_info;
862
863                 memset(&shm_info, 0, sizeof(shm_info));
864                 down_read(&shm_ids(ns).rwsem);
865                 shm_info.used_ids = shm_ids(ns).in_use;
866                 shm_get_stat(ns, &shm_info.shm_rss, &shm_info.shm_swp);
867                 shm_info.shm_tot = ns->shm_tot;
868                 shm_info.swap_attempts = 0;
869                 shm_info.swap_successes = 0;
870                 err = ipc_get_maxid(&shm_ids(ns));
871                 up_read(&shm_ids(ns).rwsem);
872                 if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
873                         err = -EFAULT;
874                         goto out;
875                 }
876
877                 err = err < 0 ? 0 : err;
878                 goto out;
879         }
880         case SHM_STAT:
881         case IPC_STAT:
882         {
883                 struct shmid64_ds tbuf;
884                 int result;
885
886                 rcu_read_lock();
887                 if (cmd == SHM_STAT) {
888                         shp = shm_obtain_object(ns, shmid);
889                         if (IS_ERR(shp)) {
890                                 err = PTR_ERR(shp);
891                                 goto out_unlock;
892                         }
893                         result = shp->shm_perm.id;
894                 } else {
895                         shp = shm_obtain_object_check(ns, shmid);
896                         if (IS_ERR(shp)) {
897                                 err = PTR_ERR(shp);
898                                 goto out_unlock;
899                         }
900                         result = 0;
901                 }
902
903                 err = -EACCES;
904                 if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
905                         goto out_unlock;
906
907                 err = security_shm_shmctl(shp, cmd);
908                 if (err)
909                         goto out_unlock;
910
911                 memset(&tbuf, 0, sizeof(tbuf));
912                 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
913                 tbuf.shm_segsz  = shp->shm_segsz;
914                 tbuf.shm_atime  = shp->shm_atim;
915                 tbuf.shm_dtime  = shp->shm_dtim;
916                 tbuf.shm_ctime  = shp->shm_ctim;
917                 tbuf.shm_cpid   = shp->shm_cprid;
918                 tbuf.shm_lpid   = shp->shm_lprid;
919                 tbuf.shm_nattch = shp->shm_nattch;
920                 rcu_read_unlock();
921
922                 if (copy_shmid_to_user(buf, &tbuf, version))
923                         err = -EFAULT;
924                 else
925                         err = result;
926                 goto out;
927         }
928         default:
929                 return -EINVAL;
930         }
931
932 out_unlock:
933         rcu_read_unlock();
934 out:
935         return err;
936 }
937
938 SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
939 {
940         struct shmid_kernel *shp;
941         int err, version;
942         struct ipc_namespace *ns;
943
944         if (cmd < 0 || shmid < 0)
945                 return -EINVAL;
946
947         version = ipc_parse_version(&cmd);
948         ns = current->nsproxy->ipc_ns;
949
950         switch (cmd) {
951         case IPC_INFO:
952         case SHM_INFO:
953         case SHM_STAT:
954         case IPC_STAT:
955                 return shmctl_nolock(ns, shmid, cmd, version, buf);
956         case IPC_RMID:
957         case IPC_SET:
958                 return shmctl_down(ns, shmid, cmd, buf, version);
959         case SHM_LOCK:
960         case SHM_UNLOCK:
961         {
962                 struct file *shm_file;
963
964                 rcu_read_lock();
965                 shp = shm_obtain_object_check(ns, shmid);
966                 if (IS_ERR(shp)) {
967                         err = PTR_ERR(shp);
968                         goto out_unlock1;
969                 }
970
971                 audit_ipc_obj(&(shp->shm_perm));
972                 err = security_shm_shmctl(shp, cmd);
973                 if (err)
974                         goto out_unlock1;
975
976                 ipc_lock_object(&shp->shm_perm);
977
978                 /* check if shm_destroy() is tearing down shp */
979                 if (!ipc_valid_object(&shp->shm_perm)) {
980                         err = -EIDRM;
981                         goto out_unlock0;
982                 }
983
984                 if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
985                         kuid_t euid = current_euid();
986                         if (!uid_eq(euid, shp->shm_perm.uid) &&
987                             !uid_eq(euid, shp->shm_perm.cuid)) {
988                                 err = -EPERM;
989                                 goto out_unlock0;
990                         }
991                         if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) {
992                                 err = -EPERM;
993                                 goto out_unlock0;
994                         }
995                 }
996
997                 shm_file = shp->shm_file;
998                 if (is_file_hugepages(shm_file))
999                         goto out_unlock0;
1000
1001                 if (cmd == SHM_LOCK) {
1002                         struct user_struct *user = current_user();
1003                         err = shmem_lock(shm_file, 1, user);
1004                         if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
1005                                 shp->shm_perm.mode |= SHM_LOCKED;
1006                                 shp->mlock_user = user;
1007                         }
1008                         goto out_unlock0;
1009                 }
1010
1011                 /* SHM_UNLOCK */
1012                 if (!(shp->shm_perm.mode & SHM_LOCKED))
1013                         goto out_unlock0;
1014                 shmem_lock(shm_file, 0, shp->mlock_user);
1015                 shp->shm_perm.mode &= ~SHM_LOCKED;
1016                 shp->mlock_user = NULL;
1017                 get_file(shm_file);
1018                 ipc_unlock_object(&shp->shm_perm);
1019                 rcu_read_unlock();
1020                 shmem_unlock_mapping(shm_file->f_mapping);
1021
1022                 fput(shm_file);
1023                 return err;
1024         }
1025         default:
1026                 return -EINVAL;
1027         }
1028
1029 out_unlock0:
1030         ipc_unlock_object(&shp->shm_perm);
1031 out_unlock1:
1032         rcu_read_unlock();
1033         return err;
1034 }
1035
1036 /*
1037  * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
1038  *
1039  * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
1040  * "raddr" thing points to kernel space, and there has to be a wrapper around
1041  * this.
1042  */
1043 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr,
1044               unsigned long shmlba)
1045 {
1046         struct shmid_kernel *shp;
1047         unsigned long addr;
1048         unsigned long size;
1049         struct file *file;
1050         int    err;
1051         unsigned long flags;
1052         unsigned long prot;
1053         int acc_mode;
1054         struct ipc_namespace *ns;
1055         struct shm_file_data *sfd;
1056         struct path path;
1057         fmode_t f_mode;
1058         unsigned long populate = 0;
1059
1060         err = -EINVAL;
1061         if (shmid < 0)
1062                 goto out;
1063         else if ((addr = (ulong)shmaddr)) {
1064                 if (addr & (shmlba - 1)) {
1065                         if (shmflg & SHM_RND)
1066                                 addr &= ~(shmlba - 1);     /* round down */
1067                         else
1068 #ifndef __ARCH_FORCE_SHMLBA
1069                                 if (addr & ~PAGE_MASK)
1070 #endif
1071                                         goto out;
1072                 }
1073                 flags = MAP_SHARED | MAP_FIXED;
1074         } else {
1075                 if ((shmflg & SHM_REMAP))
1076                         goto out;
1077
1078                 flags = MAP_SHARED;
1079         }
1080
1081         if (shmflg & SHM_RDONLY) {
1082                 prot = PROT_READ;
1083                 acc_mode = S_IRUGO;
1084                 f_mode = FMODE_READ;
1085         } else {
1086                 prot = PROT_READ | PROT_WRITE;
1087                 acc_mode = S_IRUGO | S_IWUGO;
1088                 f_mode = FMODE_READ | FMODE_WRITE;
1089         }
1090         if (shmflg & SHM_EXEC) {
1091                 prot |= PROT_EXEC;
1092                 acc_mode |= S_IXUGO;
1093         }
1094
1095         /*
1096          * We cannot rely on the fs check since SYSV IPC does have an
1097          * additional creator id...
1098          */
1099         ns = current->nsproxy->ipc_ns;
1100         rcu_read_lock();
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         err = -EACCES;
1108         if (ipcperms(ns, &shp->shm_perm, acc_mode))
1109                 goto out_unlock;
1110
1111         err = security_shm_shmat(shp, shmaddr, shmflg);
1112         if (err)
1113                 goto out_unlock;
1114
1115         ipc_lock_object(&shp->shm_perm);
1116
1117         /* check if shm_destroy() is tearing down shp */
1118         if (!ipc_valid_object(&shp->shm_perm)) {
1119                 ipc_unlock_object(&shp->shm_perm);
1120                 err = -EIDRM;
1121                 goto out_unlock;
1122         }
1123
1124         path = shp->shm_file->f_path;
1125         path_get(&path);
1126         shp->shm_nattch++;
1127         size = i_size_read(path.dentry->d_inode);
1128         ipc_unlock_object(&shp->shm_perm);
1129         rcu_read_unlock();
1130
1131         err = -ENOMEM;
1132         sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
1133         if (!sfd) {
1134                 path_put(&path);
1135                 goto out_nattch;
1136         }
1137
1138         file = alloc_file(&path, f_mode,
1139                           is_file_hugepages(shp->shm_file) ?
1140                                 &shm_file_operations_huge :
1141                                 &shm_file_operations);
1142         err = PTR_ERR(file);
1143         if (IS_ERR(file)) {
1144                 kfree(sfd);
1145                 path_put(&path);
1146                 goto out_nattch;
1147         }
1148
1149         file->private_data = sfd;
1150         file->f_mapping = shp->shm_file->f_mapping;
1151         sfd->id = shp->shm_perm.id;
1152         sfd->ns = get_ipc_ns(ns);
1153         sfd->file = shp->shm_file;
1154         sfd->vm_ops = NULL;
1155
1156         err = security_mmap_file(file, prot, flags);
1157         if (err)
1158                 goto out_fput;
1159
1160         down_write(&current->mm->mmap_sem);
1161         if (addr && !(shmflg & SHM_REMAP)) {
1162                 err = -EINVAL;
1163                 if (find_vma_intersection(current->mm, addr, addr + size))
1164                         goto invalid;
1165                 /*
1166                  * If shm segment goes below stack, make sure there is some
1167                  * space left for the stack to grow (at least 4 pages).
1168                  */
1169                 if (addr < current->mm->start_stack &&
1170                     addr > current->mm->start_stack - size - PAGE_SIZE * 5)
1171                         goto invalid;
1172         }
1173
1174         addr = do_mmap_pgoff(file, addr, size, prot, flags, 0, &populate);
1175         *raddr = addr;
1176         err = 0;
1177         if (IS_ERR_VALUE(addr))
1178                 err = (long)addr;
1179 invalid:
1180         up_write(&current->mm->mmap_sem);
1181         if (populate)
1182                 mm_populate(addr, populate);
1183
1184 out_fput:
1185         fput(file);
1186
1187 out_nattch:
1188         down_write(&shm_ids(ns).rwsem);
1189         shp = shm_lock(ns, shmid);
1190         BUG_ON(IS_ERR(shp));
1191         shp->shm_nattch--;
1192         if (shm_may_destroy(ns, shp))
1193                 shm_destroy(ns, shp);
1194         else
1195                 shm_unlock(shp);
1196         up_write(&shm_ids(ns).rwsem);
1197         return err;
1198
1199 out_unlock:
1200         rcu_read_unlock();
1201 out:
1202         return err;
1203 }
1204
1205 SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
1206 {
1207         unsigned long ret;
1208         long err;
1209
1210         err = do_shmat(shmid, shmaddr, shmflg, &ret, SHMLBA);
1211         if (err)
1212                 return err;
1213         force_successful_syscall_return();
1214         return (long)ret;
1215 }
1216
1217 /*
1218  * detach and kill segment if marked destroyed.
1219  * The work is done in shm_close.
1220  */
1221 SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
1222 {
1223         struct mm_struct *mm = current->mm;
1224         struct vm_area_struct *vma;
1225         unsigned long addr = (unsigned long)shmaddr;
1226         int retval = -EINVAL;
1227 #ifdef CONFIG_MMU
1228         loff_t size = 0;
1229         struct vm_area_struct *next;
1230 #endif
1231
1232         if (addr & ~PAGE_MASK)
1233                 return retval;
1234
1235         down_write(&mm->mmap_sem);
1236
1237         /*
1238          * This function tries to be smart and unmap shm segments that
1239          * were modified by partial mlock or munmap calls:
1240          * - It first determines the size of the shm segment that should be
1241          *   unmapped: It searches for a vma that is backed by shm and that
1242          *   started at address shmaddr. It records it's size and then unmaps
1243          *   it.
1244          * - Then it unmaps all shm vmas that started at shmaddr and that
1245          *   are within the initially determined size.
1246          * Errors from do_munmap are ignored: the function only fails if
1247          * it's called with invalid parameters or if it's called to unmap
1248          * a part of a vma. Both calls in this function are for full vmas,
1249          * the parameters are directly copied from the vma itself and always
1250          * valid - therefore do_munmap cannot fail. (famous last words?)
1251          */
1252         /*
1253          * If it had been mremap()'d, the starting address would not
1254          * match the usual checks anyway. So assume all vma's are
1255          * above the starting address given.
1256          */
1257         vma = find_vma(mm, addr);
1258
1259 #ifdef CONFIG_MMU
1260         while (vma) {
1261                 next = vma->vm_next;
1262
1263                 /*
1264                  * Check if the starting address would match, i.e. it's
1265                  * a fragment created by mprotect() and/or munmap(), or it
1266                  * otherwise it starts at this address with no hassles.
1267                  */
1268                 if ((vma->vm_ops == &shm_vm_ops) &&
1269                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1270
1271
1272                         size = file_inode(vma->vm_file)->i_size;
1273                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1274                         /*
1275                          * We discovered the size of the shm segment, so
1276                          * break out of here and fall through to the next
1277                          * loop that uses the size information to stop
1278                          * searching for matching vma's.
1279                          */
1280                         retval = 0;
1281                         vma = next;
1282                         break;
1283                 }
1284                 vma = next;
1285         }
1286
1287         /*
1288          * We need look no further than the maximum address a fragment
1289          * could possibly have landed at. Also cast things to loff_t to
1290          * prevent overflows and make comparisons vs. equal-width types.
1291          */
1292         size = PAGE_ALIGN(size);
1293         while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1294                 next = vma->vm_next;
1295
1296                 /* finding a matching vma now does not alter retval */
1297                 if ((vma->vm_ops == &shm_vm_ops) &&
1298                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1299
1300                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1301                 vma = next;
1302         }
1303
1304 #else /* CONFIG_MMU */
1305         /* under NOMMU conditions, the exact address to be destroyed must be
1306          * given */
1307         if (vma && vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1308                 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1309                 retval = 0;
1310         }
1311
1312 #endif
1313
1314         up_write(&mm->mmap_sem);
1315         return retval;
1316 }
1317
1318 #ifdef CONFIG_PROC_FS
1319 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1320 {
1321         struct user_namespace *user_ns = seq_user_ns(s);
1322         struct shmid_kernel *shp = it;
1323         unsigned long rss = 0, swp = 0;
1324
1325         shm_add_rss_swap(shp, &rss, &swp);
1326
1327 #if BITS_PER_LONG <= 32
1328 #define SIZE_SPEC "%10lu"
1329 #else
1330 #define SIZE_SPEC "%21lu"
1331 #endif
1332
1333         return seq_printf(s,
1334                           "%10d %10d  %4o " SIZE_SPEC " %5u %5u  "
1335                           "%5lu %5u %5u %5u %5u %10lu %10lu %10lu "
1336                           SIZE_SPEC " " SIZE_SPEC "\n",
1337                           shp->shm_perm.key,
1338                           shp->shm_perm.id,
1339                           shp->shm_perm.mode,
1340                           shp->shm_segsz,
1341                           shp->shm_cprid,
1342                           shp->shm_lprid,
1343                           shp->shm_nattch,
1344                           from_kuid_munged(user_ns, shp->shm_perm.uid),
1345                           from_kgid_munged(user_ns, shp->shm_perm.gid),
1346                           from_kuid_munged(user_ns, shp->shm_perm.cuid),
1347                           from_kgid_munged(user_ns, shp->shm_perm.cgid),
1348                           shp->shm_atim,
1349                           shp->shm_dtim,
1350                           shp->shm_ctim,
1351                           rss * PAGE_SIZE,
1352                           swp * PAGE_SIZE);
1353 }
1354 #endif