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fs: port fs{g,u}id helpers to mnt_idmap
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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/fs/open.c
4 *
5 * Copyright (C) 1991, 1992 Linus Torvalds
6 */
7
8#include <linux/string.h>
9#include <linux/mm.h>
10#include <linux/file.h>
11#include <linux/fdtable.h>
12#include <linux/fsnotify.h>
13#include <linux/module.h>
14#include <linux/tty.h>
15#include <linux/namei.h>
16#include <linux/backing-dev.h>
17#include <linux/capability.h>
18#include <linux/securebits.h>
19#include <linux/security.h>
20#include <linux/mount.h>
21#include <linux/fcntl.h>
22#include <linux/slab.h>
23#include <linux/uaccess.h>
24#include <linux/fs.h>
25#include <linux/personality.h>
26#include <linux/pagemap.h>
27#include <linux/syscalls.h>
28#include <linux/rcupdate.h>
29#include <linux/audit.h>
30#include <linux/falloc.h>
31#include <linux/fs_struct.h>
32#include <linux/ima.h>
33#include <linux/dnotify.h>
34#include <linux/compat.h>
35#include <linux/mnt_idmapping.h>
36
37#include "internal.h"
38
39int do_truncate(struct mnt_idmap *idmap, struct dentry *dentry,
40 loff_t length, unsigned int time_attrs, struct file *filp)
41{
42 int ret;
43 struct iattr newattrs;
44
45 /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */
46 if (length < 0)
47 return -EINVAL;
48
49 newattrs.ia_size = length;
50 newattrs.ia_valid = ATTR_SIZE | time_attrs;
51 if (filp) {
52 newattrs.ia_file = filp;
53 newattrs.ia_valid |= ATTR_FILE;
54 }
55
56 /* Remove suid, sgid, and file capabilities on truncate too */
57 ret = dentry_needs_remove_privs(idmap, dentry);
58 if (ret < 0)
59 return ret;
60 if (ret)
61 newattrs.ia_valid |= ret | ATTR_FORCE;
62
63 inode_lock(dentry->d_inode);
64 /* Note any delegations or leases have already been broken: */
65 ret = notify_change(idmap, dentry, &newattrs, NULL);
66 inode_unlock(dentry->d_inode);
67 return ret;
68}
69
70long vfs_truncate(const struct path *path, loff_t length)
71{
72 struct mnt_idmap *idmap;
73 struct inode *inode;
74 long error;
75
76 inode = path->dentry->d_inode;
77
78 /* For directories it's -EISDIR, for other non-regulars - -EINVAL */
79 if (S_ISDIR(inode->i_mode))
80 return -EISDIR;
81 if (!S_ISREG(inode->i_mode))
82 return -EINVAL;
83
84 error = mnt_want_write(path->mnt);
85 if (error)
86 goto out;
87
88 idmap = mnt_idmap(path->mnt);
89 error = inode_permission(idmap, inode, MAY_WRITE);
90 if (error)
91 goto mnt_drop_write_and_out;
92
93 error = -EPERM;
94 if (IS_APPEND(inode))
95 goto mnt_drop_write_and_out;
96
97 error = get_write_access(inode);
98 if (error)
99 goto mnt_drop_write_and_out;
100
101 /*
102 * Make sure that there are no leases. get_write_access() protects
103 * against the truncate racing with a lease-granting setlease().
104 */
105 error = break_lease(inode, O_WRONLY);
106 if (error)
107 goto put_write_and_out;
108
109 error = security_path_truncate(path);
110 if (!error)
111 error = do_truncate(idmap, path->dentry, length, 0, NULL);
112
113put_write_and_out:
114 put_write_access(inode);
115mnt_drop_write_and_out:
116 mnt_drop_write(path->mnt);
117out:
118 return error;
119}
120EXPORT_SYMBOL_GPL(vfs_truncate);
121
122long do_sys_truncate(const char __user *pathname, loff_t length)
123{
124 unsigned int lookup_flags = LOOKUP_FOLLOW;
125 struct path path;
126 int error;
127
128 if (length < 0) /* sorry, but loff_t says... */
129 return -EINVAL;
130
131retry:
132 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
133 if (!error) {
134 error = vfs_truncate(&path, length);
135 path_put(&path);
136 }
137 if (retry_estale(error, lookup_flags)) {
138 lookup_flags |= LOOKUP_REVAL;
139 goto retry;
140 }
141 return error;
142}
143
144SYSCALL_DEFINE2(truncate, const char __user *, path, long, length)
145{
146 return do_sys_truncate(path, length);
147}
148
149#ifdef CONFIG_COMPAT
150COMPAT_SYSCALL_DEFINE2(truncate, const char __user *, path, compat_off_t, length)
151{
152 return do_sys_truncate(path, length);
153}
154#endif
155
156long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
157{
158 struct inode *inode;
159 struct dentry *dentry;
160 struct fd f;
161 int error;
162
163 error = -EINVAL;
164 if (length < 0)
165 goto out;
166 error = -EBADF;
167 f = fdget(fd);
168 if (!f.file)
169 goto out;
170
171 /* explicitly opened as large or we are on 64-bit box */
172 if (f.file->f_flags & O_LARGEFILE)
173 small = 0;
174
175 dentry = f.file->f_path.dentry;
176 inode = dentry->d_inode;
177 error = -EINVAL;
178 if (!S_ISREG(inode->i_mode) || !(f.file->f_mode & FMODE_WRITE))
179 goto out_putf;
180
181 error = -EINVAL;
182 /* Cannot ftruncate over 2^31 bytes without large file support */
183 if (small && length > MAX_NON_LFS)
184 goto out_putf;
185
186 error = -EPERM;
187 /* Check IS_APPEND on real upper inode */
188 if (IS_APPEND(file_inode(f.file)))
189 goto out_putf;
190 sb_start_write(inode->i_sb);
191 error = security_file_truncate(f.file);
192 if (!error)
193 error = do_truncate(file_mnt_idmap(f.file), dentry, length,
194 ATTR_MTIME | ATTR_CTIME, f.file);
195 sb_end_write(inode->i_sb);
196out_putf:
197 fdput(f);
198out:
199 return error;
200}
201
202SYSCALL_DEFINE2(ftruncate, unsigned int, fd, unsigned long, length)
203{
204 return do_sys_ftruncate(fd, length, 1);
205}
206
207#ifdef CONFIG_COMPAT
208COMPAT_SYSCALL_DEFINE2(ftruncate, unsigned int, fd, compat_ulong_t, length)
209{
210 return do_sys_ftruncate(fd, length, 1);
211}
212#endif
213
214/* LFS versions of truncate are only needed on 32 bit machines */
215#if BITS_PER_LONG == 32
216SYSCALL_DEFINE2(truncate64, const char __user *, path, loff_t, length)
217{
218 return do_sys_truncate(path, length);
219}
220
221SYSCALL_DEFINE2(ftruncate64, unsigned int, fd, loff_t, length)
222{
223 return do_sys_ftruncate(fd, length, 0);
224}
225#endif /* BITS_PER_LONG == 32 */
226
227#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_TRUNCATE64)
228COMPAT_SYSCALL_DEFINE3(truncate64, const char __user *, pathname,
229 compat_arg_u64_dual(length))
230{
231 return ksys_truncate(pathname, compat_arg_u64_glue(length));
232}
233#endif
234
235#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_FTRUNCATE64)
236COMPAT_SYSCALL_DEFINE3(ftruncate64, unsigned int, fd,
237 compat_arg_u64_dual(length))
238{
239 return ksys_ftruncate(fd, compat_arg_u64_glue(length));
240}
241#endif
242
243int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
244{
245 struct inode *inode = file_inode(file);
246 long ret;
247
248 if (offset < 0 || len <= 0)
249 return -EINVAL;
250
251 /* Return error if mode is not supported */
252 if (mode & ~FALLOC_FL_SUPPORTED_MASK)
253 return -EOPNOTSUPP;
254
255 /* Punch hole and zero range are mutually exclusive */
256 if ((mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) ==
257 (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE))
258 return -EOPNOTSUPP;
259
260 /* Punch hole must have keep size set */
261 if ((mode & FALLOC_FL_PUNCH_HOLE) &&
262 !(mode & FALLOC_FL_KEEP_SIZE))
263 return -EOPNOTSUPP;
264
265 /* Collapse range should only be used exclusively. */
266 if ((mode & FALLOC_FL_COLLAPSE_RANGE) &&
267 (mode & ~FALLOC_FL_COLLAPSE_RANGE))
268 return -EINVAL;
269
270 /* Insert range should only be used exclusively. */
271 if ((mode & FALLOC_FL_INSERT_RANGE) &&
272 (mode & ~FALLOC_FL_INSERT_RANGE))
273 return -EINVAL;
274
275 /* Unshare range should only be used with allocate mode. */
276 if ((mode & FALLOC_FL_UNSHARE_RANGE) &&
277 (mode & ~(FALLOC_FL_UNSHARE_RANGE | FALLOC_FL_KEEP_SIZE)))
278 return -EINVAL;
279
280 if (!(file->f_mode & FMODE_WRITE))
281 return -EBADF;
282
283 /*
284 * We can only allow pure fallocate on append only files
285 */
286 if ((mode & ~FALLOC_FL_KEEP_SIZE) && IS_APPEND(inode))
287 return -EPERM;
288
289 if (IS_IMMUTABLE(inode))
290 return -EPERM;
291
292 /*
293 * We cannot allow any fallocate operation on an active swapfile
294 */
295 if (IS_SWAPFILE(inode))
296 return -ETXTBSY;
297
298 /*
299 * Revalidate the write permissions, in case security policy has
300 * changed since the files were opened.
301 */
302 ret = security_file_permission(file, MAY_WRITE);
303 if (ret)
304 return ret;
305
306 if (S_ISFIFO(inode->i_mode))
307 return -ESPIPE;
308
309 if (S_ISDIR(inode->i_mode))
310 return -EISDIR;
311
312 if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))
313 return -ENODEV;
314
315 /* Check for wrap through zero too */
316 if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0))
317 return -EFBIG;
318
319 if (!file->f_op->fallocate)
320 return -EOPNOTSUPP;
321
322 file_start_write(file);
323 ret = file->f_op->fallocate(file, mode, offset, len);
324
325 /*
326 * Create inotify and fanotify events.
327 *
328 * To keep the logic simple always create events if fallocate succeeds.
329 * This implies that events are even created if the file size remains
330 * unchanged, e.g. when using flag FALLOC_FL_KEEP_SIZE.
331 */
332 if (ret == 0)
333 fsnotify_modify(file);
334
335 file_end_write(file);
336 return ret;
337}
338EXPORT_SYMBOL_GPL(vfs_fallocate);
339
340int ksys_fallocate(int fd, int mode, loff_t offset, loff_t len)
341{
342 struct fd f = fdget(fd);
343 int error = -EBADF;
344
345 if (f.file) {
346 error = vfs_fallocate(f.file, mode, offset, len);
347 fdput(f);
348 }
349 return error;
350}
351
352SYSCALL_DEFINE4(fallocate, int, fd, int, mode, loff_t, offset, loff_t, len)
353{
354 return ksys_fallocate(fd, mode, offset, len);
355}
356
357#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_FALLOCATE)
358COMPAT_SYSCALL_DEFINE6(fallocate, int, fd, int, mode, compat_arg_u64_dual(offset),
359 compat_arg_u64_dual(len))
360{
361 return ksys_fallocate(fd, mode, compat_arg_u64_glue(offset),
362 compat_arg_u64_glue(len));
363}
364#endif
365
366/*
367 * access() needs to use the real uid/gid, not the effective uid/gid.
368 * We do this by temporarily clearing all FS-related capabilities and
369 * switching the fsuid/fsgid around to the real ones.
370 */
371static const struct cred *access_override_creds(void)
372{
373 const struct cred *old_cred;
374 struct cred *override_cred;
375
376 override_cred = prepare_creds();
377 if (!override_cred)
378 return NULL;
379
380 override_cred->fsuid = override_cred->uid;
381 override_cred->fsgid = override_cred->gid;
382
383 if (!issecure(SECURE_NO_SETUID_FIXUP)) {
384 /* Clear the capabilities if we switch to a non-root user */
385 kuid_t root_uid = make_kuid(override_cred->user_ns, 0);
386 if (!uid_eq(override_cred->uid, root_uid))
387 cap_clear(override_cred->cap_effective);
388 else
389 override_cred->cap_effective =
390 override_cred->cap_permitted;
391 }
392
393 /*
394 * The new set of credentials can *only* be used in
395 * task-synchronous circumstances, and does not need
396 * RCU freeing, unless somebody then takes a separate
397 * reference to it.
398 *
399 * NOTE! This is _only_ true because this credential
400 * is used purely for override_creds() that installs
401 * it as the subjective cred. Other threads will be
402 * accessing ->real_cred, not the subjective cred.
403 *
404 * If somebody _does_ make a copy of this (using the
405 * 'get_current_cred()' function), that will clear the
406 * non_rcu field, because now that other user may be
407 * expecting RCU freeing. But normal thread-synchronous
408 * cred accesses will keep things non-RCY.
409 */
410 override_cred->non_rcu = 1;
411
412 old_cred = override_creds(override_cred);
413
414 /* override_cred() gets its own ref */
415 put_cred(override_cred);
416
417 return old_cred;
418}
419
420static long do_faccessat(int dfd, const char __user *filename, int mode, int flags)
421{
422 struct path path;
423 struct inode *inode;
424 int res;
425 unsigned int lookup_flags = LOOKUP_FOLLOW;
426 const struct cred *old_cred = NULL;
427
428 if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */
429 return -EINVAL;
430
431 if (flags & ~(AT_EACCESS | AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH))
432 return -EINVAL;
433
434 if (flags & AT_SYMLINK_NOFOLLOW)
435 lookup_flags &= ~LOOKUP_FOLLOW;
436 if (flags & AT_EMPTY_PATH)
437 lookup_flags |= LOOKUP_EMPTY;
438
439 if (!(flags & AT_EACCESS)) {
440 old_cred = access_override_creds();
441 if (!old_cred)
442 return -ENOMEM;
443 }
444
445retry:
446 res = user_path_at(dfd, filename, lookup_flags, &path);
447 if (res)
448 goto out;
449
450 inode = d_backing_inode(path.dentry);
451
452 if ((mode & MAY_EXEC) && S_ISREG(inode->i_mode)) {
453 /*
454 * MAY_EXEC on regular files is denied if the fs is mounted
455 * with the "noexec" flag.
456 */
457 res = -EACCES;
458 if (path_noexec(&path))
459 goto out_path_release;
460 }
461
462 res = inode_permission(mnt_idmap(path.mnt), inode, mode | MAY_ACCESS);
463 /* SuS v2 requires we report a read only fs too */
464 if (res || !(mode & S_IWOTH) || special_file(inode->i_mode))
465 goto out_path_release;
466 /*
467 * This is a rare case where using __mnt_is_readonly()
468 * is OK without a mnt_want/drop_write() pair. Since
469 * no actual write to the fs is performed here, we do
470 * not need to telegraph to that to anyone.
471 *
472 * By doing this, we accept that this access is
473 * inherently racy and know that the fs may change
474 * state before we even see this result.
475 */
476 if (__mnt_is_readonly(path.mnt))
477 res = -EROFS;
478
479out_path_release:
480 path_put(&path);
481 if (retry_estale(res, lookup_flags)) {
482 lookup_flags |= LOOKUP_REVAL;
483 goto retry;
484 }
485out:
486 if (old_cred)
487 revert_creds(old_cred);
488
489 return res;
490}
491
492SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode)
493{
494 return do_faccessat(dfd, filename, mode, 0);
495}
496
497SYSCALL_DEFINE4(faccessat2, int, dfd, const char __user *, filename, int, mode,
498 int, flags)
499{
500 return do_faccessat(dfd, filename, mode, flags);
501}
502
503SYSCALL_DEFINE2(access, const char __user *, filename, int, mode)
504{
505 return do_faccessat(AT_FDCWD, filename, mode, 0);
506}
507
508SYSCALL_DEFINE1(chdir, const char __user *, filename)
509{
510 struct path path;
511 int error;
512 unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
513retry:
514 error = user_path_at(AT_FDCWD, filename, lookup_flags, &path);
515 if (error)
516 goto out;
517
518 error = path_permission(&path, MAY_EXEC | MAY_CHDIR);
519 if (error)
520 goto dput_and_out;
521
522 set_fs_pwd(current->fs, &path);
523
524dput_and_out:
525 path_put(&path);
526 if (retry_estale(error, lookup_flags)) {
527 lookup_flags |= LOOKUP_REVAL;
528 goto retry;
529 }
530out:
531 return error;
532}
533
534SYSCALL_DEFINE1(fchdir, unsigned int, fd)
535{
536 struct fd f = fdget_raw(fd);
537 int error;
538
539 error = -EBADF;
540 if (!f.file)
541 goto out;
542
543 error = -ENOTDIR;
544 if (!d_can_lookup(f.file->f_path.dentry))
545 goto out_putf;
546
547 error = file_permission(f.file, MAY_EXEC | MAY_CHDIR);
548 if (!error)
549 set_fs_pwd(current->fs, &f.file->f_path);
550out_putf:
551 fdput(f);
552out:
553 return error;
554}
555
556SYSCALL_DEFINE1(chroot, const char __user *, filename)
557{
558 struct path path;
559 int error;
560 unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
561retry:
562 error = user_path_at(AT_FDCWD, filename, lookup_flags, &path);
563 if (error)
564 goto out;
565
566 error = path_permission(&path, MAY_EXEC | MAY_CHDIR);
567 if (error)
568 goto dput_and_out;
569
570 error = -EPERM;
571 if (!ns_capable(current_user_ns(), CAP_SYS_CHROOT))
572 goto dput_and_out;
573 error = security_path_chroot(&path);
574 if (error)
575 goto dput_and_out;
576
577 set_fs_root(current->fs, &path);
578 error = 0;
579dput_and_out:
580 path_put(&path);
581 if (retry_estale(error, lookup_flags)) {
582 lookup_flags |= LOOKUP_REVAL;
583 goto retry;
584 }
585out:
586 return error;
587}
588
589int chmod_common(const struct path *path, umode_t mode)
590{
591 struct inode *inode = path->dentry->d_inode;
592 struct inode *delegated_inode = NULL;
593 struct iattr newattrs;
594 int error;
595
596 error = mnt_want_write(path->mnt);
597 if (error)
598 return error;
599retry_deleg:
600 inode_lock(inode);
601 error = security_path_chmod(path, mode);
602 if (error)
603 goto out_unlock;
604 newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
605 newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
606 error = notify_change(mnt_idmap(path->mnt), path->dentry,
607 &newattrs, &delegated_inode);
608out_unlock:
609 inode_unlock(inode);
610 if (delegated_inode) {
611 error = break_deleg_wait(&delegated_inode);
612 if (!error)
613 goto retry_deleg;
614 }
615 mnt_drop_write(path->mnt);
616 return error;
617}
618
619int vfs_fchmod(struct file *file, umode_t mode)
620{
621 audit_file(file);
622 return chmod_common(&file->f_path, mode);
623}
624
625SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode)
626{
627 struct fd f = fdget(fd);
628 int err = -EBADF;
629
630 if (f.file) {
631 err = vfs_fchmod(f.file, mode);
632 fdput(f);
633 }
634 return err;
635}
636
637static int do_fchmodat(int dfd, const char __user *filename, umode_t mode)
638{
639 struct path path;
640 int error;
641 unsigned int lookup_flags = LOOKUP_FOLLOW;
642retry:
643 error = user_path_at(dfd, filename, lookup_flags, &path);
644 if (!error) {
645 error = chmod_common(&path, mode);
646 path_put(&path);
647 if (retry_estale(error, lookup_flags)) {
648 lookup_flags |= LOOKUP_REVAL;
649 goto retry;
650 }
651 }
652 return error;
653}
654
655SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename,
656 umode_t, mode)
657{
658 return do_fchmodat(dfd, filename, mode);
659}
660
661SYSCALL_DEFINE2(chmod, const char __user *, filename, umode_t, mode)
662{
663 return do_fchmodat(AT_FDCWD, filename, mode);
664}
665
666/**
667 * setattr_vfsuid - check and set ia_fsuid attribute
668 * @kuid: new inode owner
669 *
670 * Check whether @kuid is valid and if so generate and set vfsuid_t in
671 * ia_vfsuid.
672 *
673 * Return: true if @kuid is valid, false if not.
674 */
675static inline bool setattr_vfsuid(struct iattr *attr, kuid_t kuid)
676{
677 if (!uid_valid(kuid))
678 return false;
679 attr->ia_valid |= ATTR_UID;
680 attr->ia_vfsuid = VFSUIDT_INIT(kuid);
681 return true;
682}
683
684/**
685 * setattr_vfsgid - check and set ia_fsgid attribute
686 * @kgid: new inode owner
687 *
688 * Check whether @kgid is valid and if so generate and set vfsgid_t in
689 * ia_vfsgid.
690 *
691 * Return: true if @kgid is valid, false if not.
692 */
693static inline bool setattr_vfsgid(struct iattr *attr, kgid_t kgid)
694{
695 if (!gid_valid(kgid))
696 return false;
697 attr->ia_valid |= ATTR_GID;
698 attr->ia_vfsgid = VFSGIDT_INIT(kgid);
699 return true;
700}
701
702int chown_common(const struct path *path, uid_t user, gid_t group)
703{
704 struct mnt_idmap *idmap;
705 struct user_namespace *mnt_userns, *fs_userns;
706 struct inode *inode = path->dentry->d_inode;
707 struct inode *delegated_inode = NULL;
708 int error;
709 struct iattr newattrs;
710 kuid_t uid;
711 kgid_t gid;
712
713 uid = make_kuid(current_user_ns(), user);
714 gid = make_kgid(current_user_ns(), group);
715
716 idmap = mnt_idmap(path->mnt);
717 mnt_userns = mnt_idmap_owner(idmap);
718 fs_userns = i_user_ns(inode);
719
720retry_deleg:
721 newattrs.ia_vfsuid = INVALID_VFSUID;
722 newattrs.ia_vfsgid = INVALID_VFSGID;
723 newattrs.ia_valid = ATTR_CTIME;
724 if ((user != (uid_t)-1) && !setattr_vfsuid(&newattrs, uid))
725 return -EINVAL;
726 if ((group != (gid_t)-1) && !setattr_vfsgid(&newattrs, gid))
727 return -EINVAL;
728 inode_lock(inode);
729 if (!S_ISDIR(inode->i_mode))
730 newattrs.ia_valid |= ATTR_KILL_SUID | ATTR_KILL_PRIV |
731 setattr_should_drop_sgid(idmap, inode);
732 /* Continue to send actual fs values, not the mount values. */
733 error = security_path_chown(
734 path,
735 from_vfsuid(mnt_userns, fs_userns, newattrs.ia_vfsuid),
736 from_vfsgid(mnt_userns, fs_userns, newattrs.ia_vfsgid));
737 if (!error)
738 error = notify_change(idmap, path->dentry, &newattrs,
739 &delegated_inode);
740 inode_unlock(inode);
741 if (delegated_inode) {
742 error = break_deleg_wait(&delegated_inode);
743 if (!error)
744 goto retry_deleg;
745 }
746 return error;
747}
748
749int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group,
750 int flag)
751{
752 struct path path;
753 int error = -EINVAL;
754 int lookup_flags;
755
756 if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
757 goto out;
758
759 lookup_flags = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
760 if (flag & AT_EMPTY_PATH)
761 lookup_flags |= LOOKUP_EMPTY;
762retry:
763 error = user_path_at(dfd, filename, lookup_flags, &path);
764 if (error)
765 goto out;
766 error = mnt_want_write(path.mnt);
767 if (error)
768 goto out_release;
769 error = chown_common(&path, user, group);
770 mnt_drop_write(path.mnt);
771out_release:
772 path_put(&path);
773 if (retry_estale(error, lookup_flags)) {
774 lookup_flags |= LOOKUP_REVAL;
775 goto retry;
776 }
777out:
778 return error;
779}
780
781SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
782 gid_t, group, int, flag)
783{
784 return do_fchownat(dfd, filename, user, group, flag);
785}
786
787SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group)
788{
789 return do_fchownat(AT_FDCWD, filename, user, group, 0);
790}
791
792SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group)
793{
794 return do_fchownat(AT_FDCWD, filename, user, group,
795 AT_SYMLINK_NOFOLLOW);
796}
797
798int vfs_fchown(struct file *file, uid_t user, gid_t group)
799{
800 int error;
801
802 error = mnt_want_write_file(file);
803 if (error)
804 return error;
805 audit_file(file);
806 error = chown_common(&file->f_path, user, group);
807 mnt_drop_write_file(file);
808 return error;
809}
810
811int ksys_fchown(unsigned int fd, uid_t user, gid_t group)
812{
813 struct fd f = fdget(fd);
814 int error = -EBADF;
815
816 if (f.file) {
817 error = vfs_fchown(f.file, user, group);
818 fdput(f);
819 }
820 return error;
821}
822
823SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group)
824{
825 return ksys_fchown(fd, user, group);
826}
827
828static int do_dentry_open(struct file *f,
829 struct inode *inode,
830 int (*open)(struct inode *, struct file *))
831{
832 static const struct file_operations empty_fops = {};
833 int error;
834
835 path_get(&f->f_path);
836 f->f_inode = inode;
837 f->f_mapping = inode->i_mapping;
838 f->f_wb_err = filemap_sample_wb_err(f->f_mapping);
839 f->f_sb_err = file_sample_sb_err(f);
840
841 if (unlikely(f->f_flags & O_PATH)) {
842 f->f_mode = FMODE_PATH | FMODE_OPENED;
843 f->f_op = &empty_fops;
844 return 0;
845 }
846
847 if ((f->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) {
848 i_readcount_inc(inode);
849 } else if (f->f_mode & FMODE_WRITE && !special_file(inode->i_mode)) {
850 error = get_write_access(inode);
851 if (unlikely(error))
852 goto cleanup_file;
853 error = __mnt_want_write(f->f_path.mnt);
854 if (unlikely(error)) {
855 put_write_access(inode);
856 goto cleanup_file;
857 }
858 f->f_mode |= FMODE_WRITER;
859 }
860
861 /* POSIX.1-2008/SUSv4 Section XSI 2.9.7 */
862 if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode))
863 f->f_mode |= FMODE_ATOMIC_POS;
864
865 f->f_op = fops_get(inode->i_fop);
866 if (WARN_ON(!f->f_op)) {
867 error = -ENODEV;
868 goto cleanup_all;
869 }
870
871 error = security_file_open(f);
872 if (error)
873 goto cleanup_all;
874
875 error = break_lease(locks_inode(f), f->f_flags);
876 if (error)
877 goto cleanup_all;
878
879 /* normally all 3 are set; ->open() can clear them if needed */
880 f->f_mode |= FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE;
881 if (!open)
882 open = f->f_op->open;
883 if (open) {
884 error = open(inode, f);
885 if (error)
886 goto cleanup_all;
887 }
888 f->f_mode |= FMODE_OPENED;
889 if ((f->f_mode & FMODE_READ) &&
890 likely(f->f_op->read || f->f_op->read_iter))
891 f->f_mode |= FMODE_CAN_READ;
892 if ((f->f_mode & FMODE_WRITE) &&
893 likely(f->f_op->write || f->f_op->write_iter))
894 f->f_mode |= FMODE_CAN_WRITE;
895 if ((f->f_mode & FMODE_LSEEK) && !f->f_op->llseek)
896 f->f_mode &= ~FMODE_LSEEK;
897 if (f->f_mapping->a_ops && f->f_mapping->a_ops->direct_IO)
898 f->f_mode |= FMODE_CAN_ODIRECT;
899
900 f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
901 f->f_iocb_flags = iocb_flags(f);
902
903 file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
904
905 if ((f->f_flags & O_DIRECT) && !(f->f_mode & FMODE_CAN_ODIRECT))
906 return -EINVAL;
907
908 /*
909 * XXX: Huge page cache doesn't support writing yet. Drop all page
910 * cache for this file before processing writes.
911 */
912 if (f->f_mode & FMODE_WRITE) {
913 /*
914 * Paired with smp_mb() in collapse_file() to ensure nr_thps
915 * is up to date and the update to i_writecount by
916 * get_write_access() is visible. Ensures subsequent insertion
917 * of THPs into the page cache will fail.
918 */
919 smp_mb();
920 if (filemap_nr_thps(inode->i_mapping)) {
921 struct address_space *mapping = inode->i_mapping;
922
923 filemap_invalidate_lock(inode->i_mapping);
924 /*
925 * unmap_mapping_range just need to be called once
926 * here, because the private pages is not need to be
927 * unmapped mapping (e.g. data segment of dynamic
928 * shared libraries here).
929 */
930 unmap_mapping_range(mapping, 0, 0, 0);
931 truncate_inode_pages(mapping, 0);
932 filemap_invalidate_unlock(inode->i_mapping);
933 }
934 }
935
936 return 0;
937
938cleanup_all:
939 if (WARN_ON_ONCE(error > 0))
940 error = -EINVAL;
941 fops_put(f->f_op);
942 put_file_access(f);
943cleanup_file:
944 path_put(&f->f_path);
945 f->f_path.mnt = NULL;
946 f->f_path.dentry = NULL;
947 f->f_inode = NULL;
948 return error;
949}
950
951/**
952 * finish_open - finish opening a file
953 * @file: file pointer
954 * @dentry: pointer to dentry
955 * @open: open callback
956 * @opened: state of open
957 *
958 * This can be used to finish opening a file passed to i_op->atomic_open().
959 *
960 * If the open callback is set to NULL, then the standard f_op->open()
961 * filesystem callback is substituted.
962 *
963 * NB: the dentry reference is _not_ consumed. If, for example, the dentry is
964 * the return value of d_splice_alias(), then the caller needs to perform dput()
965 * on it after finish_open().
966 *
967 * Returns zero on success or -errno if the open failed.
968 */
969int finish_open(struct file *file, struct dentry *dentry,
970 int (*open)(struct inode *, struct file *))
971{
972 BUG_ON(file->f_mode & FMODE_OPENED); /* once it's opened, it's opened */
973
974 file->f_path.dentry = dentry;
975 return do_dentry_open(file, d_backing_inode(dentry), open);
976}
977EXPORT_SYMBOL(finish_open);
978
979/**
980 * finish_no_open - finish ->atomic_open() without opening the file
981 *
982 * @file: file pointer
983 * @dentry: dentry or NULL (as returned from ->lookup())
984 *
985 * This can be used to set the result of a successful lookup in ->atomic_open().
986 *
987 * NB: unlike finish_open() this function does consume the dentry reference and
988 * the caller need not dput() it.
989 *
990 * Returns "0" which must be the return value of ->atomic_open() after having
991 * called this function.
992 */
993int finish_no_open(struct file *file, struct dentry *dentry)
994{
995 file->f_path.dentry = dentry;
996 return 0;
997}
998EXPORT_SYMBOL(finish_no_open);
999
1000char *file_path(struct file *filp, char *buf, int buflen)
1001{
1002 return d_path(&filp->f_path, buf, buflen);
1003}
1004EXPORT_SYMBOL(file_path);
1005
1006/**
1007 * vfs_open - open the file at the given path
1008 * @path: path to open
1009 * @file: newly allocated file with f_flag initialized
1010 * @cred: credentials to use
1011 */
1012int vfs_open(const struct path *path, struct file *file)
1013{
1014 file->f_path = *path;
1015 return do_dentry_open(file, d_backing_inode(path->dentry), NULL);
1016}
1017
1018struct file *dentry_open(const struct path *path, int flags,
1019 const struct cred *cred)
1020{
1021 int error;
1022 struct file *f;
1023
1024 validate_creds(cred);
1025
1026 /* We must always pass in a valid mount pointer. */
1027 BUG_ON(!path->mnt);
1028
1029 f = alloc_empty_file(flags, cred);
1030 if (!IS_ERR(f)) {
1031 error = vfs_open(path, f);
1032 if (error) {
1033 fput(f);
1034 f = ERR_PTR(error);
1035 }
1036 }
1037 return f;
1038}
1039EXPORT_SYMBOL(dentry_open);
1040
1041/**
1042 * dentry_create - Create and open a file
1043 * @path: path to create
1044 * @flags: O_ flags
1045 * @mode: mode bits for new file
1046 * @cred: credentials to use
1047 *
1048 * Caller must hold the parent directory's lock, and have prepared
1049 * a negative dentry, placed in @path->dentry, for the new file.
1050 *
1051 * Caller sets @path->mnt to the vfsmount of the filesystem where
1052 * the new file is to be created. The parent directory and the
1053 * negative dentry must reside on the same filesystem instance.
1054 *
1055 * On success, returns a "struct file *". Otherwise a ERR_PTR
1056 * is returned.
1057 */
1058struct file *dentry_create(const struct path *path, int flags, umode_t mode,
1059 const struct cred *cred)
1060{
1061 struct file *f;
1062 int error;
1063
1064 validate_creds(cred);
1065 f = alloc_empty_file(flags, cred);
1066 if (IS_ERR(f))
1067 return f;
1068
1069 error = vfs_create(mnt_idmap(path->mnt),
1070 d_inode(path->dentry->d_parent),
1071 path->dentry, mode, true);
1072 if (!error)
1073 error = vfs_open(path, f);
1074
1075 if (unlikely(error)) {
1076 fput(f);
1077 return ERR_PTR(error);
1078 }
1079 return f;
1080}
1081EXPORT_SYMBOL(dentry_create);
1082
1083struct file *open_with_fake_path(const struct path *path, int flags,
1084 struct inode *inode, const struct cred *cred)
1085{
1086 struct file *f = alloc_empty_file_noaccount(flags, cred);
1087 if (!IS_ERR(f)) {
1088 int error;
1089
1090 f->f_path = *path;
1091 error = do_dentry_open(f, inode, NULL);
1092 if (error) {
1093 fput(f);
1094 f = ERR_PTR(error);
1095 }
1096 }
1097 return f;
1098}
1099EXPORT_SYMBOL(open_with_fake_path);
1100
1101#define WILL_CREATE(flags) (flags & (O_CREAT | __O_TMPFILE))
1102#define O_PATH_FLAGS (O_DIRECTORY | O_NOFOLLOW | O_PATH | O_CLOEXEC)
1103
1104inline struct open_how build_open_how(int flags, umode_t mode)
1105{
1106 struct open_how how = {
1107 .flags = flags & VALID_OPEN_FLAGS,
1108 .mode = mode & S_IALLUGO,
1109 };
1110
1111 /* O_PATH beats everything else. */
1112 if (how.flags & O_PATH)
1113 how.flags &= O_PATH_FLAGS;
1114 /* Modes should only be set for create-like flags. */
1115 if (!WILL_CREATE(how.flags))
1116 how.mode = 0;
1117 return how;
1118}
1119
1120inline int build_open_flags(const struct open_how *how, struct open_flags *op)
1121{
1122 u64 flags = how->flags;
1123 u64 strip = FMODE_NONOTIFY | O_CLOEXEC;
1124 int lookup_flags = 0;
1125 int acc_mode = ACC_MODE(flags);
1126
1127 BUILD_BUG_ON_MSG(upper_32_bits(VALID_OPEN_FLAGS),
1128 "struct open_flags doesn't yet handle flags > 32 bits");
1129
1130 /*
1131 * Strip flags that either shouldn't be set by userspace like
1132 * FMODE_NONOTIFY or that aren't relevant in determining struct
1133 * open_flags like O_CLOEXEC.
1134 */
1135 flags &= ~strip;
1136
1137 /*
1138 * Older syscalls implicitly clear all of the invalid flags or argument
1139 * values before calling build_open_flags(), but openat2(2) checks all
1140 * of its arguments.
1141 */
1142 if (flags & ~VALID_OPEN_FLAGS)
1143 return -EINVAL;
1144 if (how->resolve & ~VALID_RESOLVE_FLAGS)
1145 return -EINVAL;
1146
1147 /* Scoping flags are mutually exclusive. */
1148 if ((how->resolve & RESOLVE_BENEATH) && (how->resolve & RESOLVE_IN_ROOT))
1149 return -EINVAL;
1150
1151 /* Deal with the mode. */
1152 if (WILL_CREATE(flags)) {
1153 if (how->mode & ~S_IALLUGO)
1154 return -EINVAL;
1155 op->mode = how->mode | S_IFREG;
1156 } else {
1157 if (how->mode != 0)
1158 return -EINVAL;
1159 op->mode = 0;
1160 }
1161
1162 /*
1163 * In order to ensure programs get explicit errors when trying to use
1164 * O_TMPFILE on old kernels, O_TMPFILE is implemented such that it
1165 * looks like (O_DIRECTORY|O_RDWR & ~O_CREAT) to old kernels. But we
1166 * have to require userspace to explicitly set it.
1167 */
1168 if (flags & __O_TMPFILE) {
1169 if ((flags & O_TMPFILE_MASK) != O_TMPFILE)
1170 return -EINVAL;
1171 if (!(acc_mode & MAY_WRITE))
1172 return -EINVAL;
1173 }
1174 if (flags & O_PATH) {
1175 /* O_PATH only permits certain other flags to be set. */
1176 if (flags & ~O_PATH_FLAGS)
1177 return -EINVAL;
1178 acc_mode = 0;
1179 }
1180
1181 /*
1182 * O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only
1183 * check for O_DSYNC if the need any syncing at all we enforce it's
1184 * always set instead of having to deal with possibly weird behaviour
1185 * for malicious applications setting only __O_SYNC.
1186 */
1187 if (flags & __O_SYNC)
1188 flags |= O_DSYNC;
1189
1190 op->open_flag = flags;
1191
1192 /* O_TRUNC implies we need access checks for write permissions */
1193 if (flags & O_TRUNC)
1194 acc_mode |= MAY_WRITE;
1195
1196 /* Allow the LSM permission hook to distinguish append
1197 access from general write access. */
1198 if (flags & O_APPEND)
1199 acc_mode |= MAY_APPEND;
1200
1201 op->acc_mode = acc_mode;
1202
1203 op->intent = flags & O_PATH ? 0 : LOOKUP_OPEN;
1204
1205 if (flags & O_CREAT) {
1206 op->intent |= LOOKUP_CREATE;
1207 if (flags & O_EXCL) {
1208 op->intent |= LOOKUP_EXCL;
1209 flags |= O_NOFOLLOW;
1210 }
1211 }
1212
1213 if (flags & O_DIRECTORY)
1214 lookup_flags |= LOOKUP_DIRECTORY;
1215 if (!(flags & O_NOFOLLOW))
1216 lookup_flags |= LOOKUP_FOLLOW;
1217
1218 if (how->resolve & RESOLVE_NO_XDEV)
1219 lookup_flags |= LOOKUP_NO_XDEV;
1220 if (how->resolve & RESOLVE_NO_MAGICLINKS)
1221 lookup_flags |= LOOKUP_NO_MAGICLINKS;
1222 if (how->resolve & RESOLVE_NO_SYMLINKS)
1223 lookup_flags |= LOOKUP_NO_SYMLINKS;
1224 if (how->resolve & RESOLVE_BENEATH)
1225 lookup_flags |= LOOKUP_BENEATH;
1226 if (how->resolve & RESOLVE_IN_ROOT)
1227 lookup_flags |= LOOKUP_IN_ROOT;
1228 if (how->resolve & RESOLVE_CACHED) {
1229 /* Don't bother even trying for create/truncate/tmpfile open */
1230 if (flags & (O_TRUNC | O_CREAT | O_TMPFILE))
1231 return -EAGAIN;
1232 lookup_flags |= LOOKUP_CACHED;
1233 }
1234
1235 op->lookup_flags = lookup_flags;
1236 return 0;
1237}
1238
1239/**
1240 * file_open_name - open file and return file pointer
1241 *
1242 * @name: struct filename containing path to open
1243 * @flags: open flags as per the open(2) second argument
1244 * @mode: mode for the new file if O_CREAT is set, else ignored
1245 *
1246 * This is the helper to open a file from kernelspace if you really
1247 * have to. But in generally you should not do this, so please move
1248 * along, nothing to see here..
1249 */
1250struct file *file_open_name(struct filename *name, int flags, umode_t mode)
1251{
1252 struct open_flags op;
1253 struct open_how how = build_open_how(flags, mode);
1254 int err = build_open_flags(&how, &op);
1255 if (err)
1256 return ERR_PTR(err);
1257 return do_filp_open(AT_FDCWD, name, &op);
1258}
1259
1260/**
1261 * filp_open - open file and return file pointer
1262 *
1263 * @filename: path to open
1264 * @flags: open flags as per the open(2) second argument
1265 * @mode: mode for the new file if O_CREAT is set, else ignored
1266 *
1267 * This is the helper to open a file from kernelspace if you really
1268 * have to. But in generally you should not do this, so please move
1269 * along, nothing to see here..
1270 */
1271struct file *filp_open(const char *filename, int flags, umode_t mode)
1272{
1273 struct filename *name = getname_kernel(filename);
1274 struct file *file = ERR_CAST(name);
1275
1276 if (!IS_ERR(name)) {
1277 file = file_open_name(name, flags, mode);
1278 putname(name);
1279 }
1280 return file;
1281}
1282EXPORT_SYMBOL(filp_open);
1283
1284struct file *file_open_root(const struct path *root,
1285 const char *filename, int flags, umode_t mode)
1286{
1287 struct open_flags op;
1288 struct open_how how = build_open_how(flags, mode);
1289 int err = build_open_flags(&how, &op);
1290 if (err)
1291 return ERR_PTR(err);
1292 return do_file_open_root(root, filename, &op);
1293}
1294EXPORT_SYMBOL(file_open_root);
1295
1296static long do_sys_openat2(int dfd, const char __user *filename,
1297 struct open_how *how)
1298{
1299 struct open_flags op;
1300 int fd = build_open_flags(how, &op);
1301 struct filename *tmp;
1302
1303 if (fd)
1304 return fd;
1305
1306 tmp = getname(filename);
1307 if (IS_ERR(tmp))
1308 return PTR_ERR(tmp);
1309
1310 fd = get_unused_fd_flags(how->flags);
1311 if (fd >= 0) {
1312 struct file *f = do_filp_open(dfd, tmp, &op);
1313 if (IS_ERR(f)) {
1314 put_unused_fd(fd);
1315 fd = PTR_ERR(f);
1316 } else {
1317 fsnotify_open(f);
1318 fd_install(fd, f);
1319 }
1320 }
1321 putname(tmp);
1322 return fd;
1323}
1324
1325long do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode)
1326{
1327 struct open_how how = build_open_how(flags, mode);
1328 return do_sys_openat2(dfd, filename, &how);
1329}
1330
1331
1332SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode)
1333{
1334 if (force_o_largefile())
1335 flags |= O_LARGEFILE;
1336 return do_sys_open(AT_FDCWD, filename, flags, mode);
1337}
1338
1339SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags,
1340 umode_t, mode)
1341{
1342 if (force_o_largefile())
1343 flags |= O_LARGEFILE;
1344 return do_sys_open(dfd, filename, flags, mode);
1345}
1346
1347SYSCALL_DEFINE4(openat2, int, dfd, const char __user *, filename,
1348 struct open_how __user *, how, size_t, usize)
1349{
1350 int err;
1351 struct open_how tmp;
1352
1353 BUILD_BUG_ON(sizeof(struct open_how) < OPEN_HOW_SIZE_VER0);
1354 BUILD_BUG_ON(sizeof(struct open_how) != OPEN_HOW_SIZE_LATEST);
1355
1356 if (unlikely(usize < OPEN_HOW_SIZE_VER0))
1357 return -EINVAL;
1358
1359 err = copy_struct_from_user(&tmp, sizeof(tmp), how, usize);
1360 if (err)
1361 return err;
1362
1363 audit_openat2_how(&tmp);
1364
1365 /* O_LARGEFILE is only allowed for non-O_PATH. */
1366 if (!(tmp.flags & O_PATH) && force_o_largefile())
1367 tmp.flags |= O_LARGEFILE;
1368
1369 return do_sys_openat2(dfd, filename, &tmp);
1370}
1371
1372#ifdef CONFIG_COMPAT
1373/*
1374 * Exactly like sys_open(), except that it doesn't set the
1375 * O_LARGEFILE flag.
1376 */
1377COMPAT_SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode)
1378{
1379 return do_sys_open(AT_FDCWD, filename, flags, mode);
1380}
1381
1382/*
1383 * Exactly like sys_openat(), except that it doesn't set the
1384 * O_LARGEFILE flag.
1385 */
1386COMPAT_SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags, umode_t, mode)
1387{
1388 return do_sys_open(dfd, filename, flags, mode);
1389}
1390#endif
1391
1392#ifndef __alpha__
1393
1394/*
1395 * For backward compatibility? Maybe this should be moved
1396 * into arch/i386 instead?
1397 */
1398SYSCALL_DEFINE2(creat, const char __user *, pathname, umode_t, mode)
1399{
1400 int flags = O_CREAT | O_WRONLY | O_TRUNC;
1401
1402 if (force_o_largefile())
1403 flags |= O_LARGEFILE;
1404 return do_sys_open(AT_FDCWD, pathname, flags, mode);
1405}
1406#endif
1407
1408/*
1409 * "id" is the POSIX thread ID. We use the
1410 * files pointer for this..
1411 */
1412int filp_close(struct file *filp, fl_owner_t id)
1413{
1414 int retval = 0;
1415
1416 if (!file_count(filp)) {
1417 printk(KERN_ERR "VFS: Close: file count is 0\n");
1418 return 0;
1419 }
1420
1421 if (filp->f_op->flush)
1422 retval = filp->f_op->flush(filp, id);
1423
1424 if (likely(!(filp->f_mode & FMODE_PATH))) {
1425 dnotify_flush(filp, id);
1426 locks_remove_posix(filp, id);
1427 }
1428 fput(filp);
1429 return retval;
1430}
1431
1432EXPORT_SYMBOL(filp_close);
1433
1434/*
1435 * Careful here! We test whether the file pointer is NULL before
1436 * releasing the fd. This ensures that one clone task can't release
1437 * an fd while another clone is opening it.
1438 */
1439SYSCALL_DEFINE1(close, unsigned int, fd)
1440{
1441 int retval = close_fd(fd);
1442
1443 /* can't restart close syscall because file table entry was cleared */
1444 if (unlikely(retval == -ERESTARTSYS ||
1445 retval == -ERESTARTNOINTR ||
1446 retval == -ERESTARTNOHAND ||
1447 retval == -ERESTART_RESTARTBLOCK))
1448 retval = -EINTR;
1449
1450 return retval;
1451}
1452
1453/**
1454 * close_range() - Close all file descriptors in a given range.
1455 *
1456 * @fd: starting file descriptor to close
1457 * @max_fd: last file descriptor to close
1458 * @flags: reserved for future extensions
1459 *
1460 * This closes a range of file descriptors. All file descriptors
1461 * from @fd up to and including @max_fd are closed.
1462 * Currently, errors to close a given file descriptor are ignored.
1463 */
1464SYSCALL_DEFINE3(close_range, unsigned int, fd, unsigned int, max_fd,
1465 unsigned int, flags)
1466{
1467 return __close_range(fd, max_fd, flags);
1468}
1469
1470/*
1471 * This routine simulates a hangup on the tty, to arrange that users
1472 * are given clean terminals at login time.
1473 */
1474SYSCALL_DEFINE0(vhangup)
1475{
1476 if (capable(CAP_SYS_TTY_CONFIG)) {
1477 tty_vhangup_self();
1478 return 0;
1479 }
1480 return -EPERM;
1481}
1482
1483/*
1484 * Called when an inode is about to be open.
1485 * We use this to disallow opening large files on 32bit systems if
1486 * the caller didn't specify O_LARGEFILE. On 64bit systems we force
1487 * on this flag in sys_open.
1488 */
1489int generic_file_open(struct inode * inode, struct file * filp)
1490{
1491 if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS)
1492 return -EOVERFLOW;
1493 return 0;
1494}
1495
1496EXPORT_SYMBOL(generic_file_open);
1497
1498/*
1499 * This is used by subsystems that don't want seekable
1500 * file descriptors. The function is not supposed to ever fail, the only
1501 * reason it returns an 'int' and not 'void' is so that it can be plugged
1502 * directly into file_operations structure.
1503 */
1504int nonseekable_open(struct inode *inode, struct file *filp)
1505{
1506 filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);
1507 return 0;
1508}
1509
1510EXPORT_SYMBOL(nonseekable_open);
1511
1512/*
1513 * stream_open is used by subsystems that want stream-like file descriptors.
1514 * Such file descriptors are not seekable and don't have notion of position
1515 * (file.f_pos is always 0 and ppos passed to .read()/.write() is always NULL).
1516 * Contrary to file descriptors of other regular files, .read() and .write()
1517 * can run simultaneously.
1518 *
1519 * stream_open never fails and is marked to return int so that it could be
1520 * directly used as file_operations.open .
1521 */
1522int stream_open(struct inode *inode, struct file *filp)
1523{
1524 filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE | FMODE_ATOMIC_POS);
1525 filp->f_mode |= FMODE_STREAM;
1526 return 0;
1527}
1528
1529EXPORT_SYMBOL(stream_open);
Linux 6.x block layer and io_uring tree(s)