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1/*
2 * linux/fs/open.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7#include <linux/string.h>
8#include <linux/mm.h>
9#include <linux/file.h>
10#include <linux/fdtable.h>
11#include <linux/fsnotify.h>
12#include <linux/module.h>
13#include <linux/tty.h>
14#include <linux/namei.h>
15#include <linux/backing-dev.h>
16#include <linux/capability.h>
17#include <linux/securebits.h>
18#include <linux/security.h>
19#include <linux/mount.h>
20#include <linux/fcntl.h>
21#include <linux/slab.h>
22#include <linux/uaccess.h>
23#include <linux/fs.h>
24#include <linux/personality.h>
25#include <linux/pagemap.h>
26#include <linux/syscalls.h>
27#include <linux/rcupdate.h>
28#include <linux/audit.h>
29#include <linux/falloc.h>
30#include <linux/fs_struct.h>
31#include <linux/ima.h>
32#include <linux/dnotify.h>
33#include <linux/compat.h>
34
35#include "internal.h"
36
37int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs,
38 struct file *filp)
39{
40 int ret;
41 struct iattr newattrs;
42
43 /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */
44 if (length < 0)
45 return -EINVAL;
46
47 newattrs.ia_size = length;
48 newattrs.ia_valid = ATTR_SIZE | time_attrs;
49 if (filp) {
50 newattrs.ia_file = filp;
51 newattrs.ia_valid |= ATTR_FILE;
52 }
53
54 /* Remove suid, sgid, and file capabilities on truncate too */
55 ret = dentry_needs_remove_privs(dentry);
56 if (ret < 0)
57 return ret;
58 if (ret)
59 newattrs.ia_valid |= ret | ATTR_FORCE;
60
61 inode_lock(dentry->d_inode);
62 /* Note any delegations or leases have already been broken: */
63 ret = notify_change(dentry, &newattrs, NULL);
64 inode_unlock(dentry->d_inode);
65 return ret;
66}
67
68long vfs_truncate(const struct path *path, loff_t length)
69{
70 struct inode *inode;
71 struct dentry *upperdentry;
72 long error;
73
74 inode = path->dentry->d_inode;
75
76 /* For directories it's -EISDIR, for other non-regulars - -EINVAL */
77 if (S_ISDIR(inode->i_mode))
78 return -EISDIR;
79 if (!S_ISREG(inode->i_mode))
80 return -EINVAL;
81
82 error = mnt_want_write(path->mnt);
83 if (error)
84 goto out;
85
86 error = inode_permission(inode, MAY_WRITE);
87 if (error)
88 goto mnt_drop_write_and_out;
89
90 error = -EPERM;
91 if (IS_APPEND(inode))
92 goto mnt_drop_write_and_out;
93
94 /*
95 * If this is an overlayfs then do as if opening the file so we get
96 * write access on the upper inode, not on the overlay inode. For
97 * non-overlay filesystems d_real() is an identity function.
98 */
99 upperdentry = d_real(path->dentry, NULL, O_WRONLY);
100 error = PTR_ERR(upperdentry);
101 if (IS_ERR(upperdentry))
102 goto mnt_drop_write_and_out;
103
104 error = get_write_access(upperdentry->d_inode);
105 if (error)
106 goto mnt_drop_write_and_out;
107
108 /*
109 * Make sure that there are no leases. get_write_access() protects
110 * against the truncate racing with a lease-granting setlease().
111 */
112 error = break_lease(inode, O_WRONLY);
113 if (error)
114 goto put_write_and_out;
115
116 error = locks_verify_truncate(inode, NULL, length);
117 if (!error)
118 error = security_path_truncate(path);
119 if (!error)
120 error = do_truncate(path->dentry, length, 0, NULL);
121
122put_write_and_out:
123 put_write_access(upperdentry->d_inode);
124mnt_drop_write_and_out:
125 mnt_drop_write(path->mnt);
126out:
127 return error;
128}
129EXPORT_SYMBOL_GPL(vfs_truncate);
130
131static long do_sys_truncate(const char __user *pathname, loff_t length)
132{
133 unsigned int lookup_flags = LOOKUP_FOLLOW;
134 struct path path;
135 int error;
136
137 if (length < 0) /* sorry, but loff_t says... */
138 return -EINVAL;
139
140retry:
141 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
142 if (!error) {
143 error = vfs_truncate(&path, length);
144 path_put(&path);
145 }
146 if (retry_estale(error, lookup_flags)) {
147 lookup_flags |= LOOKUP_REVAL;
148 goto retry;
149 }
150 return error;
151}
152
153SYSCALL_DEFINE2(truncate, const char __user *, path, long, length)
154{
155 return do_sys_truncate(path, length);
156}
157
158#ifdef CONFIG_COMPAT
159COMPAT_SYSCALL_DEFINE2(truncate, const char __user *, path, compat_off_t, length)
160{
161 return do_sys_truncate(path, length);
162}
163#endif
164
165static long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
166{
167 struct inode *inode;
168 struct dentry *dentry;
169 struct fd f;
170 int error;
171
172 error = -EINVAL;
173 if (length < 0)
174 goto out;
175 error = -EBADF;
176 f = fdget(fd);
177 if (!f.file)
178 goto out;
179
180 /* explicitly opened as large or we are on 64-bit box */
181 if (f.file->f_flags & O_LARGEFILE)
182 small = 0;
183
184 dentry = f.file->f_path.dentry;
185 inode = dentry->d_inode;
186 error = -EINVAL;
187 if (!S_ISREG(inode->i_mode) || !(f.file->f_mode & FMODE_WRITE))
188 goto out_putf;
189
190 error = -EINVAL;
191 /* Cannot ftruncate over 2^31 bytes without large file support */
192 if (small && length > MAX_NON_LFS)
193 goto out_putf;
194
195 error = -EPERM;
196 if (IS_APPEND(inode))
197 goto out_putf;
198
199 sb_start_write(inode->i_sb);
200 error = locks_verify_truncate(inode, f.file, length);
201 if (!error)
202 error = security_path_truncate(&f.file->f_path);
203 if (!error)
204 error = do_truncate(dentry, length, ATTR_MTIME|ATTR_CTIME, f.file);
205 sb_end_write(inode->i_sb);
206out_putf:
207 fdput(f);
208out:
209 return error;
210}
211
212SYSCALL_DEFINE2(ftruncate, unsigned int, fd, unsigned long, length)
213{
214 return do_sys_ftruncate(fd, length, 1);
215}
216
217#ifdef CONFIG_COMPAT
218COMPAT_SYSCALL_DEFINE2(ftruncate, unsigned int, fd, compat_ulong_t, length)
219{
220 return do_sys_ftruncate(fd, length, 1);
221}
222#endif
223
224/* LFS versions of truncate are only needed on 32 bit machines */
225#if BITS_PER_LONG == 32
226SYSCALL_DEFINE2(truncate64, const char __user *, path, loff_t, length)
227{
228 return do_sys_truncate(path, length);
229}
230
231SYSCALL_DEFINE2(ftruncate64, unsigned int, fd, loff_t, length)
232{
233 return do_sys_ftruncate(fd, length, 0);
234}
235#endif /* BITS_PER_LONG == 32 */
236
237
238int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
239{
240 struct inode *inode = file_inode(file);
241 long ret;
242
243 if (offset < 0 || len <= 0)
244 return -EINVAL;
245
246 /* Return error if mode is not supported */
247 if (mode & ~FALLOC_FL_SUPPORTED_MASK)
248 return -EOPNOTSUPP;
249
250 /* Punch hole and zero range are mutually exclusive */
251 if ((mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) ==
252 (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE))
253 return -EOPNOTSUPP;
254
255 /* Punch hole must have keep size set */
256 if ((mode & FALLOC_FL_PUNCH_HOLE) &&
257 !(mode & FALLOC_FL_KEEP_SIZE))
258 return -EOPNOTSUPP;
259
260 /* Collapse range should only be used exclusively. */
261 if ((mode & FALLOC_FL_COLLAPSE_RANGE) &&
262 (mode & ~FALLOC_FL_COLLAPSE_RANGE))
263 return -EINVAL;
264
265 /* Insert range should only be used exclusively. */
266 if ((mode & FALLOC_FL_INSERT_RANGE) &&
267 (mode & ~FALLOC_FL_INSERT_RANGE))
268 return -EINVAL;
269
270 /* Unshare range should only be used with allocate mode. */
271 if ((mode & FALLOC_FL_UNSHARE_RANGE) &&
272 (mode & ~(FALLOC_FL_UNSHARE_RANGE | FALLOC_FL_KEEP_SIZE)))
273 return -EINVAL;
274
275 if (!(file->f_mode & FMODE_WRITE))
276 return -EBADF;
277
278 /*
279 * We can only allow pure fallocate on append only files
280 */
281 if ((mode & ~FALLOC_FL_KEEP_SIZE) && IS_APPEND(inode))
282 return -EPERM;
283
284 if (IS_IMMUTABLE(inode))
285 return -EPERM;
286
287 /*
288 * We cannot allow any fallocate operation on an active swapfile
289 */
290 if (IS_SWAPFILE(inode))
291 return -ETXTBSY;
292
293 /*
294 * Revalidate the write permissions, in case security policy has
295 * changed since the files were opened.
296 */
297 ret = security_file_permission(file, MAY_WRITE);
298 if (ret)
299 return ret;
300
301 if (S_ISFIFO(inode->i_mode))
302 return -ESPIPE;
303
304 /*
305 * Let individual file system decide if it supports preallocation
306 * for directories or not.
307 */
308 if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode) &&
309 !S_ISBLK(inode->i_mode))
310 return -ENODEV;
311
312 /* Check for wrap through zero too */
313 if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0))
314 return -EFBIG;
315
316 if (!file->f_op->fallocate)
317 return -EOPNOTSUPP;
318
319 sb_start_write(inode->i_sb);
320 ret = file->f_op->fallocate(file, mode, offset, len);
321
322 /*
323 * Create inotify and fanotify events.
324 *
325 * To keep the logic simple always create events if fallocate succeeds.
326 * This implies that events are even created if the file size remains
327 * unchanged, e.g. when using flag FALLOC_FL_KEEP_SIZE.
328 */
329 if (ret == 0)
330 fsnotify_modify(file);
331
332 sb_end_write(inode->i_sb);
333 return ret;
334}
335EXPORT_SYMBOL_GPL(vfs_fallocate);
336
337SYSCALL_DEFINE4(fallocate, int, fd, int, mode, loff_t, offset, loff_t, len)
338{
339 struct fd f = fdget(fd);
340 int error = -EBADF;
341
342 if (f.file) {
343 error = vfs_fallocate(f.file, mode, offset, len);
344 fdput(f);
345 }
346 return error;
347}
348
349/*
350 * access() needs to use the real uid/gid, not the effective uid/gid.
351 * We do this by temporarily clearing all FS-related capabilities and
352 * switching the fsuid/fsgid around to the real ones.
353 */
354SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode)
355{
356 const struct cred *old_cred;
357 struct cred *override_cred;
358 struct path path;
359 struct inode *inode;
360 int res;
361 unsigned int lookup_flags = LOOKUP_FOLLOW;
362
363 if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */
364 return -EINVAL;
365
366 override_cred = prepare_creds();
367 if (!override_cred)
368 return -ENOMEM;
369
370 override_cred->fsuid = override_cred->uid;
371 override_cred->fsgid = override_cred->gid;
372
373 if (!issecure(SECURE_NO_SETUID_FIXUP)) {
374 /* Clear the capabilities if we switch to a non-root user */
375 kuid_t root_uid = make_kuid(override_cred->user_ns, 0);
376 if (!uid_eq(override_cred->uid, root_uid))
377 cap_clear(override_cred->cap_effective);
378 else
379 override_cred->cap_effective =
380 override_cred->cap_permitted;
381 }
382
383 old_cred = override_creds(override_cred);
384retry:
385 res = user_path_at(dfd, filename, lookup_flags, &path);
386 if (res)
387 goto out;
388
389 inode = d_backing_inode(path.dentry);
390
391 if ((mode & MAY_EXEC) && S_ISREG(inode->i_mode)) {
392 /*
393 * MAY_EXEC on regular files is denied if the fs is mounted
394 * with the "noexec" flag.
395 */
396 res = -EACCES;
397 if (path_noexec(&path))
398 goto out_path_release;
399 }
400
401 res = inode_permission(inode, mode | MAY_ACCESS);
402 /* SuS v2 requires we report a read only fs too */
403 if (res || !(mode & S_IWOTH) || special_file(inode->i_mode))
404 goto out_path_release;
405 /*
406 * This is a rare case where using __mnt_is_readonly()
407 * is OK without a mnt_want/drop_write() pair. Since
408 * no actual write to the fs is performed here, we do
409 * not need to telegraph to that to anyone.
410 *
411 * By doing this, we accept that this access is
412 * inherently racy and know that the fs may change
413 * state before we even see this result.
414 */
415 if (__mnt_is_readonly(path.mnt))
416 res = -EROFS;
417
418out_path_release:
419 path_put(&path);
420 if (retry_estale(res, lookup_flags)) {
421 lookup_flags |= LOOKUP_REVAL;
422 goto retry;
423 }
424out:
425 revert_creds(old_cred);
426 put_cred(override_cred);
427 return res;
428}
429
430SYSCALL_DEFINE2(access, const char __user *, filename, int, mode)
431{
432 return sys_faccessat(AT_FDCWD, filename, mode);
433}
434
435SYSCALL_DEFINE1(chdir, const char __user *, filename)
436{
437 struct path path;
438 int error;
439 unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
440retry:
441 error = user_path_at(AT_FDCWD, filename, lookup_flags, &path);
442 if (error)
443 goto out;
444
445 error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);
446 if (error)
447 goto dput_and_out;
448
449 set_fs_pwd(current->fs, &path);
450
451dput_and_out:
452 path_put(&path);
453 if (retry_estale(error, lookup_flags)) {
454 lookup_flags |= LOOKUP_REVAL;
455 goto retry;
456 }
457out:
458 return error;
459}
460
461SYSCALL_DEFINE1(fchdir, unsigned int, fd)
462{
463 struct fd f = fdget_raw(fd);
464 struct inode *inode;
465 int error = -EBADF;
466
467 error = -EBADF;
468 if (!f.file)
469 goto out;
470
471 inode = file_inode(f.file);
472
473 error = -ENOTDIR;
474 if (!S_ISDIR(inode->i_mode))
475 goto out_putf;
476
477 error = inode_permission(inode, MAY_EXEC | MAY_CHDIR);
478 if (!error)
479 set_fs_pwd(current->fs, &f.file->f_path);
480out_putf:
481 fdput(f);
482out:
483 return error;
484}
485
486SYSCALL_DEFINE1(chroot, const char __user *, filename)
487{
488 struct path path;
489 int error;
490 unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
491retry:
492 error = user_path_at(AT_FDCWD, filename, lookup_flags, &path);
493 if (error)
494 goto out;
495
496 error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);
497 if (error)
498 goto dput_and_out;
499
500 error = -EPERM;
501 if (!ns_capable(current_user_ns(), CAP_SYS_CHROOT))
502 goto dput_and_out;
503 error = security_path_chroot(&path);
504 if (error)
505 goto dput_and_out;
506
507 set_fs_root(current->fs, &path);
508 error = 0;
509dput_and_out:
510 path_put(&path);
511 if (retry_estale(error, lookup_flags)) {
512 lookup_flags |= LOOKUP_REVAL;
513 goto retry;
514 }
515out:
516 return error;
517}
518
519static int chmod_common(const struct path *path, umode_t mode)
520{
521 struct inode *inode = path->dentry->d_inode;
522 struct inode *delegated_inode = NULL;
523 struct iattr newattrs;
524 int error;
525
526 error = mnt_want_write(path->mnt);
527 if (error)
528 return error;
529retry_deleg:
530 inode_lock(inode);
531 error = security_path_chmod(path, mode);
532 if (error)
533 goto out_unlock;
534 newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
535 newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
536 error = notify_change(path->dentry, &newattrs, &delegated_inode);
537out_unlock:
538 inode_unlock(inode);
539 if (delegated_inode) {
540 error = break_deleg_wait(&delegated_inode);
541 if (!error)
542 goto retry_deleg;
543 }
544 mnt_drop_write(path->mnt);
545 return error;
546}
547
548SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode)
549{
550 struct fd f = fdget(fd);
551 int err = -EBADF;
552
553 if (f.file) {
554 audit_file(f.file);
555 err = chmod_common(&f.file->f_path, mode);
556 fdput(f);
557 }
558 return err;
559}
560
561SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename, umode_t, mode)
562{
563 struct path path;
564 int error;
565 unsigned int lookup_flags = LOOKUP_FOLLOW;
566retry:
567 error = user_path_at(dfd, filename, lookup_flags, &path);
568 if (!error) {
569 error = chmod_common(&path, mode);
570 path_put(&path);
571 if (retry_estale(error, lookup_flags)) {
572 lookup_flags |= LOOKUP_REVAL;
573 goto retry;
574 }
575 }
576 return error;
577}
578
579SYSCALL_DEFINE2(chmod, const char __user *, filename, umode_t, mode)
580{
581 return sys_fchmodat(AT_FDCWD, filename, mode);
582}
583
584static int chown_common(const struct path *path, uid_t user, gid_t group)
585{
586 struct inode *inode = path->dentry->d_inode;
587 struct inode *delegated_inode = NULL;
588 int error;
589 struct iattr newattrs;
590 kuid_t uid;
591 kgid_t gid;
592
593 uid = make_kuid(current_user_ns(), user);
594 gid = make_kgid(current_user_ns(), group);
595
596retry_deleg:
597 newattrs.ia_valid = ATTR_CTIME;
598 if (user != (uid_t) -1) {
599 if (!uid_valid(uid))
600 return -EINVAL;
601 newattrs.ia_valid |= ATTR_UID;
602 newattrs.ia_uid = uid;
603 }
604 if (group != (gid_t) -1) {
605 if (!gid_valid(gid))
606 return -EINVAL;
607 newattrs.ia_valid |= ATTR_GID;
608 newattrs.ia_gid = gid;
609 }
610 if (!S_ISDIR(inode->i_mode))
611 newattrs.ia_valid |=
612 ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;
613 inode_lock(inode);
614 error = security_path_chown(path, uid, gid);
615 if (!error)
616 error = notify_change(path->dentry, &newattrs, &delegated_inode);
617 inode_unlock(inode);
618 if (delegated_inode) {
619 error = break_deleg_wait(&delegated_inode);
620 if (!error)
621 goto retry_deleg;
622 }
623 return error;
624}
625
626SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
627 gid_t, group, int, flag)
628{
629 struct path path;
630 int error = -EINVAL;
631 int lookup_flags;
632
633 if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
634 goto out;
635
636 lookup_flags = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
637 if (flag & AT_EMPTY_PATH)
638 lookup_flags |= LOOKUP_EMPTY;
639retry:
640 error = user_path_at(dfd, filename, lookup_flags, &path);
641 if (error)
642 goto out;
643 error = mnt_want_write(path.mnt);
644 if (error)
645 goto out_release;
646 error = chown_common(&path, user, group);
647 mnt_drop_write(path.mnt);
648out_release:
649 path_put(&path);
650 if (retry_estale(error, lookup_flags)) {
651 lookup_flags |= LOOKUP_REVAL;
652 goto retry;
653 }
654out:
655 return error;
656}
657
658SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group)
659{
660 return sys_fchownat(AT_FDCWD, filename, user, group, 0);
661}
662
663SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group)
664{
665 return sys_fchownat(AT_FDCWD, filename, user, group,
666 AT_SYMLINK_NOFOLLOW);
667}
668
669SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group)
670{
671 struct fd f = fdget(fd);
672 int error = -EBADF;
673
674 if (!f.file)
675 goto out;
676
677 error = mnt_want_write_file(f.file);
678 if (error)
679 goto out_fput;
680 audit_file(f.file);
681 error = chown_common(&f.file->f_path, user, group);
682 mnt_drop_write_file(f.file);
683out_fput:
684 fdput(f);
685out:
686 return error;
687}
688
689int open_check_o_direct(struct file *f)
690{
691 /* NB: we're sure to have correct a_ops only after f_op->open */
692 if (f->f_flags & O_DIRECT) {
693 if (!f->f_mapping->a_ops || !f->f_mapping->a_ops->direct_IO)
694 return -EINVAL;
695 }
696 return 0;
697}
698
699static int do_dentry_open(struct file *f,
700 struct inode *inode,
701 int (*open)(struct inode *, struct file *),
702 const struct cred *cred)
703{
704 static const struct file_operations empty_fops = {};
705 int error;
706
707 f->f_mode = OPEN_FMODE(f->f_flags) | FMODE_LSEEK |
708 FMODE_PREAD | FMODE_PWRITE;
709
710 path_get(&f->f_path);
711 f->f_inode = inode;
712 f->f_mapping = inode->i_mapping;
713
714 if (unlikely(f->f_flags & O_PATH)) {
715 f->f_mode = FMODE_PATH;
716 f->f_op = &empty_fops;
717 return 0;
718 }
719
720 if (f->f_mode & FMODE_WRITE && !special_file(inode->i_mode)) {
721 error = get_write_access(inode);
722 if (unlikely(error))
723 goto cleanup_file;
724 error = __mnt_want_write(f->f_path.mnt);
725 if (unlikely(error)) {
726 put_write_access(inode);
727 goto cleanup_file;
728 }
729 f->f_mode |= FMODE_WRITER;
730 }
731
732 /* POSIX.1-2008/SUSv4 Section XSI 2.9.7 */
733 if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode))
734 f->f_mode |= FMODE_ATOMIC_POS;
735
736 f->f_op = fops_get(inode->i_fop);
737 if (unlikely(WARN_ON(!f->f_op))) {
738 error = -ENODEV;
739 goto cleanup_all;
740 }
741
742 error = security_file_open(f, cred);
743 if (error)
744 goto cleanup_all;
745
746 error = break_lease(locks_inode(f), f->f_flags);
747 if (error)
748 goto cleanup_all;
749
750 if (!open)
751 open = f->f_op->open;
752 if (open) {
753 error = open(inode, f);
754 if (error)
755 goto cleanup_all;
756 }
757 if ((f->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
758 i_readcount_inc(inode);
759 if ((f->f_mode & FMODE_READ) &&
760 likely(f->f_op->read || f->f_op->read_iter))
761 f->f_mode |= FMODE_CAN_READ;
762 if ((f->f_mode & FMODE_WRITE) &&
763 likely(f->f_op->write || f->f_op->write_iter))
764 f->f_mode |= FMODE_CAN_WRITE;
765
766 f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
767
768 file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
769
770 return 0;
771
772cleanup_all:
773 fops_put(f->f_op);
774 if (f->f_mode & FMODE_WRITER) {
775 put_write_access(inode);
776 __mnt_drop_write(f->f_path.mnt);
777 }
778cleanup_file:
779 path_put(&f->f_path);
780 f->f_path.mnt = NULL;
781 f->f_path.dentry = NULL;
782 f->f_inode = NULL;
783 return error;
784}
785
786/**
787 * finish_open - finish opening a file
788 * @file: file pointer
789 * @dentry: pointer to dentry
790 * @open: open callback
791 * @opened: state of open
792 *
793 * This can be used to finish opening a file passed to i_op->atomic_open().
794 *
795 * If the open callback is set to NULL, then the standard f_op->open()
796 * filesystem callback is substituted.
797 *
798 * NB: the dentry reference is _not_ consumed. If, for example, the dentry is
799 * the return value of d_splice_alias(), then the caller needs to perform dput()
800 * on it after finish_open().
801 *
802 * On successful return @file is a fully instantiated open file. After this, if
803 * an error occurs in ->atomic_open(), it needs to clean up with fput().
804 *
805 * Returns zero on success or -errno if the open failed.
806 */
807int finish_open(struct file *file, struct dentry *dentry,
808 int (*open)(struct inode *, struct file *),
809 int *opened)
810{
811 int error;
812 BUG_ON(*opened & FILE_OPENED); /* once it's opened, it's opened */
813
814 file->f_path.dentry = dentry;
815 error = do_dentry_open(file, d_backing_inode(dentry), open,
816 current_cred());
817 if (!error)
818 *opened |= FILE_OPENED;
819
820 return error;
821}
822EXPORT_SYMBOL(finish_open);
823
824/**
825 * finish_no_open - finish ->atomic_open() without opening the file
826 *
827 * @file: file pointer
828 * @dentry: dentry or NULL (as returned from ->lookup())
829 *
830 * This can be used to set the result of a successful lookup in ->atomic_open().
831 *
832 * NB: unlike finish_open() this function does consume the dentry reference and
833 * the caller need not dput() it.
834 *
835 * Returns "1" which must be the return value of ->atomic_open() after having
836 * called this function.
837 */
838int finish_no_open(struct file *file, struct dentry *dentry)
839{
840 file->f_path.dentry = dentry;
841 return 1;
842}
843EXPORT_SYMBOL(finish_no_open);
844
845char *file_path(struct file *filp, char *buf, int buflen)
846{
847 return d_path(&filp->f_path, buf, buflen);
848}
849EXPORT_SYMBOL(file_path);
850
851/**
852 * vfs_open - open the file at the given path
853 * @path: path to open
854 * @file: newly allocated file with f_flag initialized
855 * @cred: credentials to use
856 */
857int vfs_open(const struct path *path, struct file *file,
858 const struct cred *cred)
859{
860 struct dentry *dentry = d_real(path->dentry, NULL, file->f_flags);
861
862 if (IS_ERR(dentry))
863 return PTR_ERR(dentry);
864
865 file->f_path = *path;
866 return do_dentry_open(file, d_backing_inode(dentry), NULL, cred);
867}
868
869struct file *dentry_open(const struct path *path, int flags,
870 const struct cred *cred)
871{
872 int error;
873 struct file *f;
874
875 validate_creds(cred);
876
877 /* We must always pass in a valid mount pointer. */
878 BUG_ON(!path->mnt);
879
880 f = get_empty_filp();
881 if (!IS_ERR(f)) {
882 f->f_flags = flags;
883 error = vfs_open(path, f, cred);
884 if (!error) {
885 /* from now on we need fput() to dispose of f */
886 error = open_check_o_direct(f);
887 if (error) {
888 fput(f);
889 f = ERR_PTR(error);
890 }
891 } else {
892 put_filp(f);
893 f = ERR_PTR(error);
894 }
895 }
896 return f;
897}
898EXPORT_SYMBOL(dentry_open);
899
900static inline int build_open_flags(int flags, umode_t mode, struct open_flags *op)
901{
902 int lookup_flags = 0;
903 int acc_mode = ACC_MODE(flags);
904
905 if (flags & (O_CREAT | __O_TMPFILE))
906 op->mode = (mode & S_IALLUGO) | S_IFREG;
907 else
908 op->mode = 0;
909
910 /* Must never be set by userspace */
911 flags &= ~FMODE_NONOTIFY & ~O_CLOEXEC;
912
913 /*
914 * O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only
915 * check for O_DSYNC if the need any syncing at all we enforce it's
916 * always set instead of having to deal with possibly weird behaviour
917 * for malicious applications setting only __O_SYNC.
918 */
919 if (flags & __O_SYNC)
920 flags |= O_DSYNC;
921
922 if (flags & __O_TMPFILE) {
923 if ((flags & O_TMPFILE_MASK) != O_TMPFILE)
924 return -EINVAL;
925 if (!(acc_mode & MAY_WRITE))
926 return -EINVAL;
927 } else if (flags & O_PATH) {
928 /*
929 * If we have O_PATH in the open flag. Then we
930 * cannot have anything other than the below set of flags
931 */
932 flags &= O_DIRECTORY | O_NOFOLLOW | O_PATH;
933 acc_mode = 0;
934 }
935
936 op->open_flag = flags;
937
938 /* O_TRUNC implies we need access checks for write permissions */
939 if (flags & O_TRUNC)
940 acc_mode |= MAY_WRITE;
941
942 /* Allow the LSM permission hook to distinguish append
943 access from general write access. */
944 if (flags & O_APPEND)
945 acc_mode |= MAY_APPEND;
946
947 op->acc_mode = acc_mode;
948
949 op->intent = flags & O_PATH ? 0 : LOOKUP_OPEN;
950
951 if (flags & O_CREAT) {
952 op->intent |= LOOKUP_CREATE;
953 if (flags & O_EXCL)
954 op->intent |= LOOKUP_EXCL;
955 }
956
957 if (flags & O_DIRECTORY)
958 lookup_flags |= LOOKUP_DIRECTORY;
959 if (!(flags & O_NOFOLLOW))
960 lookup_flags |= LOOKUP_FOLLOW;
961 op->lookup_flags = lookup_flags;
962 return 0;
963}
964
965/**
966 * file_open_name - open file and return file pointer
967 *
968 * @name: struct filename containing path to open
969 * @flags: open flags as per the open(2) second argument
970 * @mode: mode for the new file if O_CREAT is set, else ignored
971 *
972 * This is the helper to open a file from kernelspace if you really
973 * have to. But in generally you should not do this, so please move
974 * along, nothing to see here..
975 */
976struct file *file_open_name(struct filename *name, int flags, umode_t mode)
977{
978 struct open_flags op;
979 int err = build_open_flags(flags, mode, &op);
980 return err ? ERR_PTR(err) : do_filp_open(AT_FDCWD, name, &op);
981}
982
983/**
984 * filp_open - open file and return file pointer
985 *
986 * @filename: path to open
987 * @flags: open flags as per the open(2) second argument
988 * @mode: mode for the new file if O_CREAT is set, else ignored
989 *
990 * This is the helper to open a file from kernelspace if you really
991 * have to. But in generally you should not do this, so please move
992 * along, nothing to see here..
993 */
994struct file *filp_open(const char *filename, int flags, umode_t mode)
995{
996 struct filename *name = getname_kernel(filename);
997 struct file *file = ERR_CAST(name);
998
999 if (!IS_ERR(name)) {
1000 file = file_open_name(name, flags, mode);
1001 putname(name);
1002 }
1003 return file;
1004}
1005EXPORT_SYMBOL(filp_open);
1006
1007struct file *file_open_root(struct dentry *dentry, struct vfsmount *mnt,
1008 const char *filename, int flags, umode_t mode)
1009{
1010 struct open_flags op;
1011 int err = build_open_flags(flags, mode, &op);
1012 if (err)
1013 return ERR_PTR(err);
1014 return do_file_open_root(dentry, mnt, filename, &op);
1015}
1016EXPORT_SYMBOL(file_open_root);
1017
1018struct file *filp_clone_open(struct file *oldfile)
1019{
1020 struct file *file;
1021 int retval;
1022
1023 file = get_empty_filp();
1024 if (IS_ERR(file))
1025 return file;
1026
1027 file->f_flags = oldfile->f_flags;
1028 retval = vfs_open(&oldfile->f_path, file, oldfile->f_cred);
1029 if (retval) {
1030 put_filp(file);
1031 return ERR_PTR(retval);
1032 }
1033
1034 return file;
1035}
1036EXPORT_SYMBOL(filp_clone_open);
1037
1038long do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode)
1039{
1040 struct open_flags op;
1041 int fd = build_open_flags(flags, mode, &op);
1042 struct filename *tmp;
1043
1044 if (fd)
1045 return fd;
1046
1047 tmp = getname(filename);
1048 if (IS_ERR(tmp))
1049 return PTR_ERR(tmp);
1050
1051 fd = get_unused_fd_flags(flags);
1052 if (fd >= 0) {
1053 struct file *f = do_filp_open(dfd, tmp, &op);
1054 if (IS_ERR(f)) {
1055 put_unused_fd(fd);
1056 fd = PTR_ERR(f);
1057 } else {
1058 fsnotify_open(f);
1059 fd_install(fd, f);
1060 }
1061 }
1062 putname(tmp);
1063 return fd;
1064}
1065
1066SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode)
1067{
1068 if (force_o_largefile())
1069 flags |= O_LARGEFILE;
1070
1071 return do_sys_open(AT_FDCWD, filename, flags, mode);
1072}
1073
1074SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags,
1075 umode_t, mode)
1076{
1077 if (force_o_largefile())
1078 flags |= O_LARGEFILE;
1079
1080 return do_sys_open(dfd, filename, flags, mode);
1081}
1082
1083#ifndef __alpha__
1084
1085/*
1086 * For backward compatibility? Maybe this should be moved
1087 * into arch/i386 instead?
1088 */
1089SYSCALL_DEFINE2(creat, const char __user *, pathname, umode_t, mode)
1090{
1091 return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode);
1092}
1093
1094#endif
1095
1096/*
1097 * "id" is the POSIX thread ID. We use the
1098 * files pointer for this..
1099 */
1100int filp_close(struct file *filp, fl_owner_t id)
1101{
1102 int retval = 0;
1103
1104 if (!file_count(filp)) {
1105 printk(KERN_ERR "VFS: Close: file count is 0\n");
1106 return 0;
1107 }
1108
1109 if (filp->f_op->flush)
1110 retval = filp->f_op->flush(filp, id);
1111
1112 if (likely(!(filp->f_mode & FMODE_PATH))) {
1113 dnotify_flush(filp, id);
1114 locks_remove_posix(filp, id);
1115 }
1116 fput(filp);
1117 return retval;
1118}
1119
1120EXPORT_SYMBOL(filp_close);
1121
1122/*
1123 * Careful here! We test whether the file pointer is NULL before
1124 * releasing the fd. This ensures that one clone task can't release
1125 * an fd while another clone is opening it.
1126 */
1127SYSCALL_DEFINE1(close, unsigned int, fd)
1128{
1129 int retval = __close_fd(current->files, fd);
1130
1131 /* can't restart close syscall because file table entry was cleared */
1132 if (unlikely(retval == -ERESTARTSYS ||
1133 retval == -ERESTARTNOINTR ||
1134 retval == -ERESTARTNOHAND ||
1135 retval == -ERESTART_RESTARTBLOCK))
1136 retval = -EINTR;
1137
1138 return retval;
1139}
1140EXPORT_SYMBOL(sys_close);
1141
1142/*
1143 * This routine simulates a hangup on the tty, to arrange that users
1144 * are given clean terminals at login time.
1145 */
1146SYSCALL_DEFINE0(vhangup)
1147{
1148 if (capable(CAP_SYS_TTY_CONFIG)) {
1149 tty_vhangup_self();
1150 return 0;
1151 }
1152 return -EPERM;
1153}
1154
1155/*
1156 * Called when an inode is about to be open.
1157 * We use this to disallow opening large files on 32bit systems if
1158 * the caller didn't specify O_LARGEFILE. On 64bit systems we force
1159 * on this flag in sys_open.
1160 */
1161int generic_file_open(struct inode * inode, struct file * filp)
1162{
1163 if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS)
1164 return -EOVERFLOW;
1165 return 0;
1166}
1167
1168EXPORT_SYMBOL(generic_file_open);
1169
1170/*
1171 * This is used by subsystems that don't want seekable
1172 * file descriptors. The function is not supposed to ever fail, the only
1173 * reason it returns an 'int' and not 'void' is so that it can be plugged
1174 * directly into file_operations structure.
1175 */
1176int nonseekable_open(struct inode *inode, struct file *filp)
1177{
1178 filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);
1179 return 0;
1180}
1181
1182EXPORT_SYMBOL(nonseekable_open);
1/*
2 * linux/fs/open.c
3 *
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
6
7#include <linux/string.h>
8#include <linux/mm.h>
9#include <linux/file.h>
10#include <linux/fdtable.h>
11#include <linux/fsnotify.h>
12#include <linux/module.h>
13#include <linux/tty.h>
14#include <linux/namei.h>
15#include <linux/backing-dev.h>
16#include <linux/capability.h>
17#include <linux/securebits.h>
18#include <linux/security.h>
19#include <linux/mount.h>
20#include <linux/fcntl.h>
21#include <linux/slab.h>
22#include <asm/uaccess.h>
23#include <linux/fs.h>
24#include <linux/personality.h>
25#include <linux/pagemap.h>
26#include <linux/syscalls.h>
27#include <linux/rcupdate.h>
28#include <linux/audit.h>
29#include <linux/falloc.h>
30#include <linux/fs_struct.h>
31#include <linux/ima.h>
32#include <linux/dnotify.h>
33#include <linux/compat.h>
34
35#include "internal.h"
36
37int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs,
38 struct file *filp)
39{
40 int ret;
41 struct iattr newattrs;
42
43 /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */
44 if (length < 0)
45 return -EINVAL;
46
47 newattrs.ia_size = length;
48 newattrs.ia_valid = ATTR_SIZE | time_attrs;
49 if (filp) {
50 newattrs.ia_file = filp;
51 newattrs.ia_valid |= ATTR_FILE;
52 }
53
54 /* Remove suid, sgid, and file capabilities on truncate too */
55 ret = dentry_needs_remove_privs(dentry);
56 if (ret < 0)
57 return ret;
58 if (ret)
59 newattrs.ia_valid |= ret | ATTR_FORCE;
60
61 inode_lock(dentry->d_inode);
62 /* Note any delegations or leases have already been broken: */
63 ret = notify_change(dentry, &newattrs, NULL);
64 inode_unlock(dentry->d_inode);
65 return ret;
66}
67
68long vfs_truncate(struct path *path, loff_t length)
69{
70 struct inode *inode;
71 long error;
72
73 inode = path->dentry->d_inode;
74
75 /* For directories it's -EISDIR, for other non-regulars - -EINVAL */
76 if (S_ISDIR(inode->i_mode))
77 return -EISDIR;
78 if (!S_ISREG(inode->i_mode))
79 return -EINVAL;
80
81 error = mnt_want_write(path->mnt);
82 if (error)
83 goto out;
84
85 error = inode_permission(inode, MAY_WRITE);
86 if (error)
87 goto mnt_drop_write_and_out;
88
89 error = -EPERM;
90 if (IS_APPEND(inode))
91 goto mnt_drop_write_and_out;
92
93 error = get_write_access(inode);
94 if (error)
95 goto mnt_drop_write_and_out;
96
97 /*
98 * Make sure that there are no leases. get_write_access() protects
99 * against the truncate racing with a lease-granting setlease().
100 */
101 error = break_lease(inode, O_WRONLY);
102 if (error)
103 goto put_write_and_out;
104
105 error = locks_verify_truncate(inode, NULL, length);
106 if (!error)
107 error = security_path_truncate(path);
108 if (!error)
109 error = do_truncate(path->dentry, length, 0, NULL);
110
111put_write_and_out:
112 put_write_access(inode);
113mnt_drop_write_and_out:
114 mnt_drop_write(path->mnt);
115out:
116 return error;
117}
118EXPORT_SYMBOL_GPL(vfs_truncate);
119
120static long do_sys_truncate(const char __user *pathname, loff_t length)
121{
122 unsigned int lookup_flags = LOOKUP_FOLLOW;
123 struct path path;
124 int error;
125
126 if (length < 0) /* sorry, but loff_t says... */
127 return -EINVAL;
128
129retry:
130 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
131 if (!error) {
132 error = vfs_truncate(&path, length);
133 path_put(&path);
134 }
135 if (retry_estale(error, lookup_flags)) {
136 lookup_flags |= LOOKUP_REVAL;
137 goto retry;
138 }
139 return error;
140}
141
142SYSCALL_DEFINE2(truncate, const char __user *, path, long, length)
143{
144 return do_sys_truncate(path, length);
145}
146
147#ifdef CONFIG_COMPAT
148COMPAT_SYSCALL_DEFINE2(truncate, const char __user *, path, compat_off_t, length)
149{
150 return do_sys_truncate(path, length);
151}
152#endif
153
154static long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
155{
156 struct inode *inode;
157 struct dentry *dentry;
158 struct fd f;
159 int error;
160
161 error = -EINVAL;
162 if (length < 0)
163 goto out;
164 error = -EBADF;
165 f = fdget(fd);
166 if (!f.file)
167 goto out;
168
169 /* explicitly opened as large or we are on 64-bit box */
170 if (f.file->f_flags & O_LARGEFILE)
171 small = 0;
172
173 dentry = f.file->f_path.dentry;
174 inode = dentry->d_inode;
175 error = -EINVAL;
176 if (!S_ISREG(inode->i_mode) || !(f.file->f_mode & FMODE_WRITE))
177 goto out_putf;
178
179 error = -EINVAL;
180 /* Cannot ftruncate over 2^31 bytes without large file support */
181 if (small && length > MAX_NON_LFS)
182 goto out_putf;
183
184 error = -EPERM;
185 if (IS_APPEND(inode))
186 goto out_putf;
187
188 sb_start_write(inode->i_sb);
189 error = locks_verify_truncate(inode, f.file, length);
190 if (!error)
191 error = security_path_truncate(&f.file->f_path);
192 if (!error)
193 error = do_truncate(dentry, length, ATTR_MTIME|ATTR_CTIME, f.file);
194 sb_end_write(inode->i_sb);
195out_putf:
196 fdput(f);
197out:
198 return error;
199}
200
201SYSCALL_DEFINE2(ftruncate, unsigned int, fd, unsigned long, length)
202{
203 return do_sys_ftruncate(fd, length, 1);
204}
205
206#ifdef CONFIG_COMPAT
207COMPAT_SYSCALL_DEFINE2(ftruncate, unsigned int, fd, compat_ulong_t, length)
208{
209 return do_sys_ftruncate(fd, length, 1);
210}
211#endif
212
213/* LFS versions of truncate are only needed on 32 bit machines */
214#if BITS_PER_LONG == 32
215SYSCALL_DEFINE2(truncate64, const char __user *, path, loff_t, length)
216{
217 return do_sys_truncate(path, length);
218}
219
220SYSCALL_DEFINE2(ftruncate64, unsigned int, fd, loff_t, length)
221{
222 return do_sys_ftruncate(fd, length, 0);
223}
224#endif /* BITS_PER_LONG == 32 */
225
226
227int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
228{
229 struct inode *inode = file_inode(file);
230 long ret;
231
232 if (offset < 0 || len <= 0)
233 return -EINVAL;
234
235 /* Return error if mode is not supported */
236 if (mode & ~FALLOC_FL_SUPPORTED_MASK)
237 return -EOPNOTSUPP;
238
239 /* Punch hole and zero range are mutually exclusive */
240 if ((mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) ==
241 (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE))
242 return -EOPNOTSUPP;
243
244 /* Punch hole must have keep size set */
245 if ((mode & FALLOC_FL_PUNCH_HOLE) &&
246 !(mode & FALLOC_FL_KEEP_SIZE))
247 return -EOPNOTSUPP;
248
249 /* Collapse range should only be used exclusively. */
250 if ((mode & FALLOC_FL_COLLAPSE_RANGE) &&
251 (mode & ~FALLOC_FL_COLLAPSE_RANGE))
252 return -EINVAL;
253
254 /* Insert range should only be used exclusively. */
255 if ((mode & FALLOC_FL_INSERT_RANGE) &&
256 (mode & ~FALLOC_FL_INSERT_RANGE))
257 return -EINVAL;
258
259 if (!(file->f_mode & FMODE_WRITE))
260 return -EBADF;
261
262 /*
263 * We can only allow pure fallocate on append only files
264 */
265 if ((mode & ~FALLOC_FL_KEEP_SIZE) && IS_APPEND(inode))
266 return -EPERM;
267
268 if (IS_IMMUTABLE(inode))
269 return -EPERM;
270
271 /*
272 * We cannot allow any fallocate operation on an active swapfile
273 */
274 if (IS_SWAPFILE(inode))
275 return -ETXTBSY;
276
277 /*
278 * Revalidate the write permissions, in case security policy has
279 * changed since the files were opened.
280 */
281 ret = security_file_permission(file, MAY_WRITE);
282 if (ret)
283 return ret;
284
285 if (S_ISFIFO(inode->i_mode))
286 return -ESPIPE;
287
288 /*
289 * Let individual file system decide if it supports preallocation
290 * for directories or not.
291 */
292 if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
293 return -ENODEV;
294
295 /* Check for wrap through zero too */
296 if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0))
297 return -EFBIG;
298
299 if (!file->f_op->fallocate)
300 return -EOPNOTSUPP;
301
302 sb_start_write(inode->i_sb);
303 ret = file->f_op->fallocate(file, mode, offset, len);
304
305 /*
306 * Create inotify and fanotify events.
307 *
308 * To keep the logic simple always create events if fallocate succeeds.
309 * This implies that events are even created if the file size remains
310 * unchanged, e.g. when using flag FALLOC_FL_KEEP_SIZE.
311 */
312 if (ret == 0)
313 fsnotify_modify(file);
314
315 sb_end_write(inode->i_sb);
316 return ret;
317}
318EXPORT_SYMBOL_GPL(vfs_fallocate);
319
320SYSCALL_DEFINE4(fallocate, int, fd, int, mode, loff_t, offset, loff_t, len)
321{
322 struct fd f = fdget(fd);
323 int error = -EBADF;
324
325 if (f.file) {
326 error = vfs_fallocate(f.file, mode, offset, len);
327 fdput(f);
328 }
329 return error;
330}
331
332/*
333 * access() needs to use the real uid/gid, not the effective uid/gid.
334 * We do this by temporarily clearing all FS-related capabilities and
335 * switching the fsuid/fsgid around to the real ones.
336 */
337SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode)
338{
339 const struct cred *old_cred;
340 struct cred *override_cred;
341 struct path path;
342 struct inode *inode;
343 int res;
344 unsigned int lookup_flags = LOOKUP_FOLLOW;
345
346 if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */
347 return -EINVAL;
348
349 override_cred = prepare_creds();
350 if (!override_cred)
351 return -ENOMEM;
352
353 override_cred->fsuid = override_cred->uid;
354 override_cred->fsgid = override_cred->gid;
355
356 if (!issecure(SECURE_NO_SETUID_FIXUP)) {
357 /* Clear the capabilities if we switch to a non-root user */
358 kuid_t root_uid = make_kuid(override_cred->user_ns, 0);
359 if (!uid_eq(override_cred->uid, root_uid))
360 cap_clear(override_cred->cap_effective);
361 else
362 override_cred->cap_effective =
363 override_cred->cap_permitted;
364 }
365
366 old_cred = override_creds(override_cred);
367retry:
368 res = user_path_at(dfd, filename, lookup_flags, &path);
369 if (res)
370 goto out;
371
372 inode = d_backing_inode(path.dentry);
373
374 if ((mode & MAY_EXEC) && S_ISREG(inode->i_mode)) {
375 /*
376 * MAY_EXEC on regular files is denied if the fs is mounted
377 * with the "noexec" flag.
378 */
379 res = -EACCES;
380 if (path_noexec(&path))
381 goto out_path_release;
382 }
383
384 res = inode_permission(inode, mode | MAY_ACCESS);
385 /* SuS v2 requires we report a read only fs too */
386 if (res || !(mode & S_IWOTH) || special_file(inode->i_mode))
387 goto out_path_release;
388 /*
389 * This is a rare case where using __mnt_is_readonly()
390 * is OK without a mnt_want/drop_write() pair. Since
391 * no actual write to the fs is performed here, we do
392 * not need to telegraph to that to anyone.
393 *
394 * By doing this, we accept that this access is
395 * inherently racy and know that the fs may change
396 * state before we even see this result.
397 */
398 if (__mnt_is_readonly(path.mnt))
399 res = -EROFS;
400
401out_path_release:
402 path_put(&path);
403 if (retry_estale(res, lookup_flags)) {
404 lookup_flags |= LOOKUP_REVAL;
405 goto retry;
406 }
407out:
408 revert_creds(old_cred);
409 put_cred(override_cred);
410 return res;
411}
412
413SYSCALL_DEFINE2(access, const char __user *, filename, int, mode)
414{
415 return sys_faccessat(AT_FDCWD, filename, mode);
416}
417
418SYSCALL_DEFINE1(chdir, const char __user *, filename)
419{
420 struct path path;
421 int error;
422 unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
423retry:
424 error = user_path_at(AT_FDCWD, filename, lookup_flags, &path);
425 if (error)
426 goto out;
427
428 error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);
429 if (error)
430 goto dput_and_out;
431
432 set_fs_pwd(current->fs, &path);
433
434dput_and_out:
435 path_put(&path);
436 if (retry_estale(error, lookup_flags)) {
437 lookup_flags |= LOOKUP_REVAL;
438 goto retry;
439 }
440out:
441 return error;
442}
443
444SYSCALL_DEFINE1(fchdir, unsigned int, fd)
445{
446 struct fd f = fdget_raw(fd);
447 struct inode *inode;
448 int error = -EBADF;
449
450 error = -EBADF;
451 if (!f.file)
452 goto out;
453
454 inode = file_inode(f.file);
455
456 error = -ENOTDIR;
457 if (!S_ISDIR(inode->i_mode))
458 goto out_putf;
459
460 error = inode_permission(inode, MAY_EXEC | MAY_CHDIR);
461 if (!error)
462 set_fs_pwd(current->fs, &f.file->f_path);
463out_putf:
464 fdput(f);
465out:
466 return error;
467}
468
469SYSCALL_DEFINE1(chroot, const char __user *, filename)
470{
471 struct path path;
472 int error;
473 unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
474retry:
475 error = user_path_at(AT_FDCWD, filename, lookup_flags, &path);
476 if (error)
477 goto out;
478
479 error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);
480 if (error)
481 goto dput_and_out;
482
483 error = -EPERM;
484 if (!ns_capable(current_user_ns(), CAP_SYS_CHROOT))
485 goto dput_and_out;
486 error = security_path_chroot(&path);
487 if (error)
488 goto dput_and_out;
489
490 set_fs_root(current->fs, &path);
491 error = 0;
492dput_and_out:
493 path_put(&path);
494 if (retry_estale(error, lookup_flags)) {
495 lookup_flags |= LOOKUP_REVAL;
496 goto retry;
497 }
498out:
499 return error;
500}
501
502static int chmod_common(struct path *path, umode_t mode)
503{
504 struct inode *inode = path->dentry->d_inode;
505 struct inode *delegated_inode = NULL;
506 struct iattr newattrs;
507 int error;
508
509 error = mnt_want_write(path->mnt);
510 if (error)
511 return error;
512retry_deleg:
513 inode_lock(inode);
514 error = security_path_chmod(path, mode);
515 if (error)
516 goto out_unlock;
517 newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
518 newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
519 error = notify_change(path->dentry, &newattrs, &delegated_inode);
520out_unlock:
521 inode_unlock(inode);
522 if (delegated_inode) {
523 error = break_deleg_wait(&delegated_inode);
524 if (!error)
525 goto retry_deleg;
526 }
527 mnt_drop_write(path->mnt);
528 return error;
529}
530
531SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode)
532{
533 struct fd f = fdget(fd);
534 int err = -EBADF;
535
536 if (f.file) {
537 audit_file(f.file);
538 err = chmod_common(&f.file->f_path, mode);
539 fdput(f);
540 }
541 return err;
542}
543
544SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename, umode_t, mode)
545{
546 struct path path;
547 int error;
548 unsigned int lookup_flags = LOOKUP_FOLLOW;
549retry:
550 error = user_path_at(dfd, filename, lookup_flags, &path);
551 if (!error) {
552 error = chmod_common(&path, mode);
553 path_put(&path);
554 if (retry_estale(error, lookup_flags)) {
555 lookup_flags |= LOOKUP_REVAL;
556 goto retry;
557 }
558 }
559 return error;
560}
561
562SYSCALL_DEFINE2(chmod, const char __user *, filename, umode_t, mode)
563{
564 return sys_fchmodat(AT_FDCWD, filename, mode);
565}
566
567static int chown_common(struct path *path, uid_t user, gid_t group)
568{
569 struct inode *inode = path->dentry->d_inode;
570 struct inode *delegated_inode = NULL;
571 int error;
572 struct iattr newattrs;
573 kuid_t uid;
574 kgid_t gid;
575
576 uid = make_kuid(current_user_ns(), user);
577 gid = make_kgid(current_user_ns(), group);
578
579retry_deleg:
580 newattrs.ia_valid = ATTR_CTIME;
581 if (user != (uid_t) -1) {
582 if (!uid_valid(uid))
583 return -EINVAL;
584 newattrs.ia_valid |= ATTR_UID;
585 newattrs.ia_uid = uid;
586 }
587 if (group != (gid_t) -1) {
588 if (!gid_valid(gid))
589 return -EINVAL;
590 newattrs.ia_valid |= ATTR_GID;
591 newattrs.ia_gid = gid;
592 }
593 if (!S_ISDIR(inode->i_mode))
594 newattrs.ia_valid |=
595 ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;
596 inode_lock(inode);
597 error = security_path_chown(path, uid, gid);
598 if (!error)
599 error = notify_change(path->dentry, &newattrs, &delegated_inode);
600 inode_unlock(inode);
601 if (delegated_inode) {
602 error = break_deleg_wait(&delegated_inode);
603 if (!error)
604 goto retry_deleg;
605 }
606 return error;
607}
608
609SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
610 gid_t, group, int, flag)
611{
612 struct path path;
613 int error = -EINVAL;
614 int lookup_flags;
615
616 if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
617 goto out;
618
619 lookup_flags = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
620 if (flag & AT_EMPTY_PATH)
621 lookup_flags |= LOOKUP_EMPTY;
622retry:
623 error = user_path_at(dfd, filename, lookup_flags, &path);
624 if (error)
625 goto out;
626 error = mnt_want_write(path.mnt);
627 if (error)
628 goto out_release;
629 error = chown_common(&path, user, group);
630 mnt_drop_write(path.mnt);
631out_release:
632 path_put(&path);
633 if (retry_estale(error, lookup_flags)) {
634 lookup_flags |= LOOKUP_REVAL;
635 goto retry;
636 }
637out:
638 return error;
639}
640
641SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group)
642{
643 return sys_fchownat(AT_FDCWD, filename, user, group, 0);
644}
645
646SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group)
647{
648 return sys_fchownat(AT_FDCWD, filename, user, group,
649 AT_SYMLINK_NOFOLLOW);
650}
651
652SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group)
653{
654 struct fd f = fdget(fd);
655 int error = -EBADF;
656
657 if (!f.file)
658 goto out;
659
660 error = mnt_want_write_file(f.file);
661 if (error)
662 goto out_fput;
663 audit_file(f.file);
664 error = chown_common(&f.file->f_path, user, group);
665 mnt_drop_write_file(f.file);
666out_fput:
667 fdput(f);
668out:
669 return error;
670}
671
672int open_check_o_direct(struct file *f)
673{
674 /* NB: we're sure to have correct a_ops only after f_op->open */
675 if (f->f_flags & O_DIRECT) {
676 if (!f->f_mapping->a_ops || !f->f_mapping->a_ops->direct_IO)
677 return -EINVAL;
678 }
679 return 0;
680}
681
682static int do_dentry_open(struct file *f,
683 struct inode *inode,
684 int (*open)(struct inode *, struct file *),
685 const struct cred *cred)
686{
687 static const struct file_operations empty_fops = {};
688 int error;
689
690 f->f_mode = OPEN_FMODE(f->f_flags) | FMODE_LSEEK |
691 FMODE_PREAD | FMODE_PWRITE;
692
693 path_get(&f->f_path);
694 f->f_inode = inode;
695 f->f_mapping = inode->i_mapping;
696
697 if (unlikely(f->f_flags & O_PATH)) {
698 f->f_mode = FMODE_PATH;
699 f->f_op = &empty_fops;
700 return 0;
701 }
702
703 if (f->f_mode & FMODE_WRITE && !special_file(inode->i_mode)) {
704 error = get_write_access(inode);
705 if (unlikely(error))
706 goto cleanup_file;
707 error = __mnt_want_write(f->f_path.mnt);
708 if (unlikely(error)) {
709 put_write_access(inode);
710 goto cleanup_file;
711 }
712 f->f_mode |= FMODE_WRITER;
713 }
714
715 /* POSIX.1-2008/SUSv4 Section XSI 2.9.7 */
716 if (S_ISREG(inode->i_mode))
717 f->f_mode |= FMODE_ATOMIC_POS;
718
719 f->f_op = fops_get(inode->i_fop);
720 if (unlikely(WARN_ON(!f->f_op))) {
721 error = -ENODEV;
722 goto cleanup_all;
723 }
724
725 error = security_file_open(f, cred);
726 if (error)
727 goto cleanup_all;
728
729 error = break_lease(inode, f->f_flags);
730 if (error)
731 goto cleanup_all;
732
733 if (!open)
734 open = f->f_op->open;
735 if (open) {
736 error = open(inode, f);
737 if (error)
738 goto cleanup_all;
739 }
740 if ((f->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
741 i_readcount_inc(inode);
742 if ((f->f_mode & FMODE_READ) &&
743 likely(f->f_op->read || f->f_op->read_iter))
744 f->f_mode |= FMODE_CAN_READ;
745 if ((f->f_mode & FMODE_WRITE) &&
746 likely(f->f_op->write || f->f_op->write_iter))
747 f->f_mode |= FMODE_CAN_WRITE;
748
749 f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
750
751 file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
752
753 return 0;
754
755cleanup_all:
756 fops_put(f->f_op);
757 if (f->f_mode & FMODE_WRITER) {
758 put_write_access(inode);
759 __mnt_drop_write(f->f_path.mnt);
760 }
761cleanup_file:
762 path_put(&f->f_path);
763 f->f_path.mnt = NULL;
764 f->f_path.dentry = NULL;
765 f->f_inode = NULL;
766 return error;
767}
768
769/**
770 * finish_open - finish opening a file
771 * @file: file pointer
772 * @dentry: pointer to dentry
773 * @open: open callback
774 * @opened: state of open
775 *
776 * This can be used to finish opening a file passed to i_op->atomic_open().
777 *
778 * If the open callback is set to NULL, then the standard f_op->open()
779 * filesystem callback is substituted.
780 *
781 * NB: the dentry reference is _not_ consumed. If, for example, the dentry is
782 * the return value of d_splice_alias(), then the caller needs to perform dput()
783 * on it after finish_open().
784 *
785 * On successful return @file is a fully instantiated open file. After this, if
786 * an error occurs in ->atomic_open(), it needs to clean up with fput().
787 *
788 * Returns zero on success or -errno if the open failed.
789 */
790int finish_open(struct file *file, struct dentry *dentry,
791 int (*open)(struct inode *, struct file *),
792 int *opened)
793{
794 int error;
795 BUG_ON(*opened & FILE_OPENED); /* once it's opened, it's opened */
796
797 file->f_path.dentry = dentry;
798 error = do_dentry_open(file, d_backing_inode(dentry), open,
799 current_cred());
800 if (!error)
801 *opened |= FILE_OPENED;
802
803 return error;
804}
805EXPORT_SYMBOL(finish_open);
806
807/**
808 * finish_no_open - finish ->atomic_open() without opening the file
809 *
810 * @file: file pointer
811 * @dentry: dentry or NULL (as returned from ->lookup())
812 *
813 * This can be used to set the result of a successful lookup in ->atomic_open().
814 *
815 * NB: unlike finish_open() this function does consume the dentry reference and
816 * the caller need not dput() it.
817 *
818 * Returns "1" which must be the return value of ->atomic_open() after having
819 * called this function.
820 */
821int finish_no_open(struct file *file, struct dentry *dentry)
822{
823 file->f_path.dentry = dentry;
824 return 1;
825}
826EXPORT_SYMBOL(finish_no_open);
827
828char *file_path(struct file *filp, char *buf, int buflen)
829{
830 return d_path(&filp->f_path, buf, buflen);
831}
832EXPORT_SYMBOL(file_path);
833
834/**
835 * vfs_open - open the file at the given path
836 * @path: path to open
837 * @file: newly allocated file with f_flag initialized
838 * @cred: credentials to use
839 */
840int vfs_open(const struct path *path, struct file *file,
841 const struct cred *cred)
842{
843 struct inode *inode = vfs_select_inode(path->dentry, file->f_flags);
844
845 if (IS_ERR(inode))
846 return PTR_ERR(inode);
847
848 file->f_path = *path;
849 return do_dentry_open(file, inode, NULL, cred);
850}
851
852struct file *dentry_open(const struct path *path, int flags,
853 const struct cred *cred)
854{
855 int error;
856 struct file *f;
857
858 validate_creds(cred);
859
860 /* We must always pass in a valid mount pointer. */
861 BUG_ON(!path->mnt);
862
863 f = get_empty_filp();
864 if (!IS_ERR(f)) {
865 f->f_flags = flags;
866 error = vfs_open(path, f, cred);
867 if (!error) {
868 /* from now on we need fput() to dispose of f */
869 error = open_check_o_direct(f);
870 if (error) {
871 fput(f);
872 f = ERR_PTR(error);
873 }
874 } else {
875 put_filp(f);
876 f = ERR_PTR(error);
877 }
878 }
879 return f;
880}
881EXPORT_SYMBOL(dentry_open);
882
883static inline int build_open_flags(int flags, umode_t mode, struct open_flags *op)
884{
885 int lookup_flags = 0;
886 int acc_mode = ACC_MODE(flags);
887
888 if (flags & (O_CREAT | __O_TMPFILE))
889 op->mode = (mode & S_IALLUGO) | S_IFREG;
890 else
891 op->mode = 0;
892
893 /* Must never be set by userspace */
894 flags &= ~FMODE_NONOTIFY & ~O_CLOEXEC;
895
896 /*
897 * O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only
898 * check for O_DSYNC if the need any syncing at all we enforce it's
899 * always set instead of having to deal with possibly weird behaviour
900 * for malicious applications setting only __O_SYNC.
901 */
902 if (flags & __O_SYNC)
903 flags |= O_DSYNC;
904
905 if (flags & __O_TMPFILE) {
906 if ((flags & O_TMPFILE_MASK) != O_TMPFILE)
907 return -EINVAL;
908 if (!(acc_mode & MAY_WRITE))
909 return -EINVAL;
910 } else if (flags & O_PATH) {
911 /*
912 * If we have O_PATH in the open flag. Then we
913 * cannot have anything other than the below set of flags
914 */
915 flags &= O_DIRECTORY | O_NOFOLLOW | O_PATH;
916 acc_mode = 0;
917 }
918
919 op->open_flag = flags;
920
921 /* O_TRUNC implies we need access checks for write permissions */
922 if (flags & O_TRUNC)
923 acc_mode |= MAY_WRITE;
924
925 /* Allow the LSM permission hook to distinguish append
926 access from general write access. */
927 if (flags & O_APPEND)
928 acc_mode |= MAY_APPEND;
929
930 op->acc_mode = acc_mode;
931
932 op->intent = flags & O_PATH ? 0 : LOOKUP_OPEN;
933
934 if (flags & O_CREAT) {
935 op->intent |= LOOKUP_CREATE;
936 if (flags & O_EXCL)
937 op->intent |= LOOKUP_EXCL;
938 }
939
940 if (flags & O_DIRECTORY)
941 lookup_flags |= LOOKUP_DIRECTORY;
942 if (!(flags & O_NOFOLLOW))
943 lookup_flags |= LOOKUP_FOLLOW;
944 op->lookup_flags = lookup_flags;
945 return 0;
946}
947
948/**
949 * file_open_name - open file and return file pointer
950 *
951 * @name: struct filename containing path to open
952 * @flags: open flags as per the open(2) second argument
953 * @mode: mode for the new file if O_CREAT is set, else ignored
954 *
955 * This is the helper to open a file from kernelspace if you really
956 * have to. But in generally you should not do this, so please move
957 * along, nothing to see here..
958 */
959struct file *file_open_name(struct filename *name, int flags, umode_t mode)
960{
961 struct open_flags op;
962 int err = build_open_flags(flags, mode, &op);
963 return err ? ERR_PTR(err) : do_filp_open(AT_FDCWD, name, &op);
964}
965
966/**
967 * filp_open - open file and return file pointer
968 *
969 * @filename: path to open
970 * @flags: open flags as per the open(2) second argument
971 * @mode: mode for the new file if O_CREAT is set, else ignored
972 *
973 * This is the helper to open a file from kernelspace if you really
974 * have to. But in generally you should not do this, so please move
975 * along, nothing to see here..
976 */
977struct file *filp_open(const char *filename, int flags, umode_t mode)
978{
979 struct filename *name = getname_kernel(filename);
980 struct file *file = ERR_CAST(name);
981
982 if (!IS_ERR(name)) {
983 file = file_open_name(name, flags, mode);
984 putname(name);
985 }
986 return file;
987}
988EXPORT_SYMBOL(filp_open);
989
990struct file *file_open_root(struct dentry *dentry, struct vfsmount *mnt,
991 const char *filename, int flags, umode_t mode)
992{
993 struct open_flags op;
994 int err = build_open_flags(flags, mode, &op);
995 if (err)
996 return ERR_PTR(err);
997 return do_file_open_root(dentry, mnt, filename, &op);
998}
999EXPORT_SYMBOL(file_open_root);
1000
1001long do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode)
1002{
1003 struct open_flags op;
1004 int fd = build_open_flags(flags, mode, &op);
1005 struct filename *tmp;
1006
1007 if (fd)
1008 return fd;
1009
1010 tmp = getname(filename);
1011 if (IS_ERR(tmp))
1012 return PTR_ERR(tmp);
1013
1014 fd = get_unused_fd_flags(flags);
1015 if (fd >= 0) {
1016 struct file *f = do_filp_open(dfd, tmp, &op);
1017 if (IS_ERR(f)) {
1018 put_unused_fd(fd);
1019 fd = PTR_ERR(f);
1020 } else {
1021 fsnotify_open(f);
1022 fd_install(fd, f);
1023 }
1024 }
1025 putname(tmp);
1026 return fd;
1027}
1028
1029SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode)
1030{
1031 if (force_o_largefile())
1032 flags |= O_LARGEFILE;
1033
1034 return do_sys_open(AT_FDCWD, filename, flags, mode);
1035}
1036
1037SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags,
1038 umode_t, mode)
1039{
1040 if (force_o_largefile())
1041 flags |= O_LARGEFILE;
1042
1043 return do_sys_open(dfd, filename, flags, mode);
1044}
1045
1046#ifndef __alpha__
1047
1048/*
1049 * For backward compatibility? Maybe this should be moved
1050 * into arch/i386 instead?
1051 */
1052SYSCALL_DEFINE2(creat, const char __user *, pathname, umode_t, mode)
1053{
1054 return sys_open(pathname, O_CREAT | O_WRONLY | O_TRUNC, mode);
1055}
1056
1057#endif
1058
1059/*
1060 * "id" is the POSIX thread ID. We use the
1061 * files pointer for this..
1062 */
1063int filp_close(struct file *filp, fl_owner_t id)
1064{
1065 int retval = 0;
1066
1067 if (!file_count(filp)) {
1068 printk(KERN_ERR "VFS: Close: file count is 0\n");
1069 return 0;
1070 }
1071
1072 if (filp->f_op->flush)
1073 retval = filp->f_op->flush(filp, id);
1074
1075 if (likely(!(filp->f_mode & FMODE_PATH))) {
1076 dnotify_flush(filp, id);
1077 locks_remove_posix(filp, id);
1078 }
1079 fput(filp);
1080 return retval;
1081}
1082
1083EXPORT_SYMBOL(filp_close);
1084
1085/*
1086 * Careful here! We test whether the file pointer is NULL before
1087 * releasing the fd. This ensures that one clone task can't release
1088 * an fd while another clone is opening it.
1089 */
1090SYSCALL_DEFINE1(close, unsigned int, fd)
1091{
1092 int retval = __close_fd(current->files, fd);
1093
1094 /* can't restart close syscall because file table entry was cleared */
1095 if (unlikely(retval == -ERESTARTSYS ||
1096 retval == -ERESTARTNOINTR ||
1097 retval == -ERESTARTNOHAND ||
1098 retval == -ERESTART_RESTARTBLOCK))
1099 retval = -EINTR;
1100
1101 return retval;
1102}
1103EXPORT_SYMBOL(sys_close);
1104
1105/*
1106 * This routine simulates a hangup on the tty, to arrange that users
1107 * are given clean terminals at login time.
1108 */
1109SYSCALL_DEFINE0(vhangup)
1110{
1111 if (capable(CAP_SYS_TTY_CONFIG)) {
1112 tty_vhangup_self();
1113 return 0;
1114 }
1115 return -EPERM;
1116}
1117
1118/*
1119 * Called when an inode is about to be open.
1120 * We use this to disallow opening large files on 32bit systems if
1121 * the caller didn't specify O_LARGEFILE. On 64bit systems we force
1122 * on this flag in sys_open.
1123 */
1124int generic_file_open(struct inode * inode, struct file * filp)
1125{
1126 if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS)
1127 return -EOVERFLOW;
1128 return 0;
1129}
1130
1131EXPORT_SYMBOL(generic_file_open);
1132
1133/*
1134 * This is used by subsystems that don't want seekable
1135 * file descriptors. The function is not supposed to ever fail, the only
1136 * reason it returns an 'int' and not 'void' is so that it can be plugged
1137 * directly into file_operations structure.
1138 */
1139int nonseekable_open(struct inode *inode, struct file *filp)
1140{
1141 filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);
1142 return 0;
1143}
1144
1145EXPORT_SYMBOL(nonseekable_open);