1 // SPDX-License-Identifier: GPL-2.0-only
5 * Copyright (C) 1991, 1992 Linus Torvalds
8 #include <linux/string.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>
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>
38 int do_truncate(struct user_namespace
*mnt_userns
, struct dentry
*dentry
,
39 loff_t length
, unsigned int time_attrs
, struct file
*filp
)
42 struct iattr newattrs
;
44 /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */
48 newattrs
.ia_size
= length
;
49 newattrs
.ia_valid
= ATTR_SIZE
| time_attrs
;
51 newattrs
.ia_file
= filp
;
52 newattrs
.ia_valid
|= ATTR_FILE
;
55 /* Remove suid, sgid, and file capabilities on truncate too */
56 ret
= dentry_needs_remove_privs(dentry
);
60 newattrs
.ia_valid
|= ret
| ATTR_FORCE
;
62 inode_lock(dentry
->d_inode
);
63 /* Note any delegations or leases have already been broken: */
64 ret
= notify_change(mnt_userns
, dentry
, &newattrs
, NULL
);
65 inode_unlock(dentry
->d_inode
);
69 long vfs_truncate(const struct path
*path
, loff_t length
)
71 struct user_namespace
*mnt_userns
;
75 inode
= path
->dentry
->d_inode
;
77 /* For directories it's -EISDIR, for other non-regulars - -EINVAL */
78 if (S_ISDIR(inode
->i_mode
))
80 if (!S_ISREG(inode
->i_mode
))
83 error
= mnt_want_write(path
->mnt
);
87 mnt_userns
= mnt_user_ns(path
->mnt
);
88 error
= inode_permission(mnt_userns
, inode
, MAY_WRITE
);
90 goto mnt_drop_write_and_out
;
94 goto mnt_drop_write_and_out
;
96 error
= get_write_access(inode
);
98 goto mnt_drop_write_and_out
;
101 * Make sure that there are no leases. get_write_access() protects
102 * against the truncate racing with a lease-granting setlease().
104 error
= break_lease(inode
, O_WRONLY
);
106 goto put_write_and_out
;
108 error
= security_path_truncate(path
);
110 error
= do_truncate(mnt_userns
, path
->dentry
, length
, 0, NULL
);
113 put_write_access(inode
);
114 mnt_drop_write_and_out
:
115 mnt_drop_write(path
->mnt
);
119 EXPORT_SYMBOL_GPL(vfs_truncate
);
121 long do_sys_truncate(const char __user
*pathname
, loff_t length
)
123 unsigned int lookup_flags
= LOOKUP_FOLLOW
;
127 if (length
< 0) /* sorry, but loff_t says... */
131 error
= user_path_at(AT_FDCWD
, pathname
, lookup_flags
, &path
);
133 error
= vfs_truncate(&path
, length
);
136 if (retry_estale(error
, lookup_flags
)) {
137 lookup_flags
|= LOOKUP_REVAL
;
143 SYSCALL_DEFINE2(truncate
, const char __user
*, path
, long, length
)
145 return do_sys_truncate(path
, length
);
149 COMPAT_SYSCALL_DEFINE2(truncate
, const char __user
*, path
, compat_off_t
, length
)
151 return do_sys_truncate(path
, length
);
155 long do_sys_ftruncate(unsigned int fd
, loff_t length
, int small
)
158 struct dentry
*dentry
;
170 /* explicitly opened as large or we are on 64-bit box */
171 if (f
.file
->f_flags
& O_LARGEFILE
)
174 dentry
= f
.file
->f_path
.dentry
;
175 inode
= dentry
->d_inode
;
177 if (!S_ISREG(inode
->i_mode
) || !(f
.file
->f_mode
& FMODE_WRITE
))
181 /* Cannot ftruncate over 2^31 bytes without large file support */
182 if (small
&& length
> MAX_NON_LFS
)
186 /* Check IS_APPEND on real upper inode */
187 if (IS_APPEND(file_inode(f
.file
)))
189 sb_start_write(inode
->i_sb
);
190 error
= security_path_truncate(&f
.file
->f_path
);
192 error
= do_truncate(file_mnt_user_ns(f
.file
), dentry
, length
,
193 ATTR_MTIME
| ATTR_CTIME
, f
.file
);
194 sb_end_write(inode
->i_sb
);
201 SYSCALL_DEFINE2(ftruncate
, unsigned int, fd
, unsigned long, length
)
203 return do_sys_ftruncate(fd
, length
, 1);
207 COMPAT_SYSCALL_DEFINE2(ftruncate
, unsigned int, fd
, compat_ulong_t
, length
)
209 return do_sys_ftruncate(fd
, length
, 1);
213 /* LFS versions of truncate are only needed on 32 bit machines */
214 #if BITS_PER_LONG == 32
215 SYSCALL_DEFINE2(truncate64
, const char __user
*, path
, loff_t
, length
)
217 return do_sys_truncate(path
, length
);
220 SYSCALL_DEFINE2(ftruncate64
, unsigned int, fd
, loff_t
, length
)
222 return do_sys_ftruncate(fd
, length
, 0);
224 #endif /* BITS_PER_LONG == 32 */
227 int vfs_fallocate(struct file
*file
, int mode
, loff_t offset
, loff_t len
)
229 struct inode
*inode
= file_inode(file
);
232 if (offset
< 0 || len
<= 0)
235 /* Return error if mode is not supported */
236 if (mode
& ~FALLOC_FL_SUPPORTED_MASK
)
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
))
244 /* Punch hole must have keep size set */
245 if ((mode
& FALLOC_FL_PUNCH_HOLE
) &&
246 !(mode
& FALLOC_FL_KEEP_SIZE
))
249 /* Collapse range should only be used exclusively. */
250 if ((mode
& FALLOC_FL_COLLAPSE_RANGE
) &&
251 (mode
& ~FALLOC_FL_COLLAPSE_RANGE
))
254 /* Insert range should only be used exclusively. */
255 if ((mode
& FALLOC_FL_INSERT_RANGE
) &&
256 (mode
& ~FALLOC_FL_INSERT_RANGE
))
259 /* Unshare range should only be used with allocate mode. */
260 if ((mode
& FALLOC_FL_UNSHARE_RANGE
) &&
261 (mode
& ~(FALLOC_FL_UNSHARE_RANGE
| FALLOC_FL_KEEP_SIZE
)))
264 if (!(file
->f_mode
& FMODE_WRITE
))
268 * We can only allow pure fallocate on append only files
270 if ((mode
& ~FALLOC_FL_KEEP_SIZE
) && IS_APPEND(inode
))
273 if (IS_IMMUTABLE(inode
))
277 * We cannot allow any fallocate operation on an active swapfile
279 if (IS_SWAPFILE(inode
))
283 * Revalidate the write permissions, in case security policy has
284 * changed since the files were opened.
286 ret
= security_file_permission(file
, MAY_WRITE
);
290 if (S_ISFIFO(inode
->i_mode
))
293 if (S_ISDIR(inode
->i_mode
))
296 if (!S_ISREG(inode
->i_mode
) && !S_ISBLK(inode
->i_mode
))
299 /* Check for wrap through zero too */
300 if (((offset
+ len
) > inode
->i_sb
->s_maxbytes
) || ((offset
+ len
) < 0))
303 if (!file
->f_op
->fallocate
)
306 file_start_write(file
);
307 ret
= file
->f_op
->fallocate(file
, mode
, offset
, len
);
310 * Create inotify and fanotify events.
312 * To keep the logic simple always create events if fallocate succeeds.
313 * This implies that events are even created if the file size remains
314 * unchanged, e.g. when using flag FALLOC_FL_KEEP_SIZE.
317 fsnotify_modify(file
);
319 file_end_write(file
);
322 EXPORT_SYMBOL_GPL(vfs_fallocate
);
324 int ksys_fallocate(int fd
, int mode
, loff_t offset
, loff_t len
)
326 struct fd f
= fdget(fd
);
330 error
= vfs_fallocate(f
.file
, mode
, offset
, len
);
336 SYSCALL_DEFINE4(fallocate
, int, fd
, int, mode
, loff_t
, offset
, loff_t
, len
)
338 return ksys_fallocate(fd
, mode
, offset
, len
);
342 * access() needs to use the real uid/gid, not the effective uid/gid.
343 * We do this by temporarily clearing all FS-related capabilities and
344 * switching the fsuid/fsgid around to the real ones.
346 static const struct cred
*access_override_creds(void)
348 const struct cred
*old_cred
;
349 struct cred
*override_cred
;
351 override_cred
= prepare_creds();
355 override_cred
->fsuid
= override_cred
->uid
;
356 override_cred
->fsgid
= override_cred
->gid
;
358 if (!issecure(SECURE_NO_SETUID_FIXUP
)) {
359 /* Clear the capabilities if we switch to a non-root user */
360 kuid_t root_uid
= make_kuid(override_cred
->user_ns
, 0);
361 if (!uid_eq(override_cred
->uid
, root_uid
))
362 cap_clear(override_cred
->cap_effective
);
364 override_cred
->cap_effective
=
365 override_cred
->cap_permitted
;
369 * The new set of credentials can *only* be used in
370 * task-synchronous circumstances, and does not need
371 * RCU freeing, unless somebody then takes a separate
374 * NOTE! This is _only_ true because this credential
375 * is used purely for override_creds() that installs
376 * it as the subjective cred. Other threads will be
377 * accessing ->real_cred, not the subjective cred.
379 * If somebody _does_ make a copy of this (using the
380 * 'get_current_cred()' function), that will clear the
381 * non_rcu field, because now that other user may be
382 * expecting RCU freeing. But normal thread-synchronous
383 * cred accesses will keep things non-RCY.
385 override_cred
->non_rcu
= 1;
387 old_cred
= override_creds(override_cred
);
389 /* override_cred() gets its own ref */
390 put_cred(override_cred
);
395 static long do_faccessat(int dfd
, const char __user
*filename
, int mode
, int flags
)
400 unsigned int lookup_flags
= LOOKUP_FOLLOW
;
401 const struct cred
*old_cred
= NULL
;
403 if (mode
& ~S_IRWXO
) /* where's F_OK, X_OK, W_OK, R_OK? */
406 if (flags
& ~(AT_EACCESS
| AT_SYMLINK_NOFOLLOW
| AT_EMPTY_PATH
))
409 if (flags
& AT_SYMLINK_NOFOLLOW
)
410 lookup_flags
&= ~LOOKUP_FOLLOW
;
411 if (flags
& AT_EMPTY_PATH
)
412 lookup_flags
|= LOOKUP_EMPTY
;
414 if (!(flags
& AT_EACCESS
)) {
415 old_cred
= access_override_creds();
421 res
= user_path_at(dfd
, filename
, lookup_flags
, &path
);
425 inode
= d_backing_inode(path
.dentry
);
427 if ((mode
& MAY_EXEC
) && S_ISREG(inode
->i_mode
)) {
429 * MAY_EXEC on regular files is denied if the fs is mounted
430 * with the "noexec" flag.
433 if (path_noexec(&path
))
434 goto out_path_release
;
437 res
= inode_permission(mnt_user_ns(path
.mnt
), inode
, mode
| MAY_ACCESS
);
438 /* SuS v2 requires we report a read only fs too */
439 if (res
|| !(mode
& S_IWOTH
) || special_file(inode
->i_mode
))
440 goto out_path_release
;
442 * This is a rare case where using __mnt_is_readonly()
443 * is OK without a mnt_want/drop_write() pair. Since
444 * no actual write to the fs is performed here, we do
445 * not need to telegraph to that to anyone.
447 * By doing this, we accept that this access is
448 * inherently racy and know that the fs may change
449 * state before we even see this result.
451 if (__mnt_is_readonly(path
.mnt
))
456 if (retry_estale(res
, lookup_flags
)) {
457 lookup_flags
|= LOOKUP_REVAL
;
462 revert_creds(old_cred
);
467 SYSCALL_DEFINE3(faccessat
, int, dfd
, const char __user
*, filename
, int, mode
)
469 return do_faccessat(dfd
, filename
, mode
, 0);
472 SYSCALL_DEFINE4(faccessat2
, int, dfd
, const char __user
*, filename
, int, mode
,
475 return do_faccessat(dfd
, filename
, mode
, flags
);
478 SYSCALL_DEFINE2(access
, const char __user
*, filename
, int, mode
)
480 return do_faccessat(AT_FDCWD
, filename
, mode
, 0);
483 SYSCALL_DEFINE1(chdir
, const char __user
*, filename
)
487 unsigned int lookup_flags
= LOOKUP_FOLLOW
| LOOKUP_DIRECTORY
;
489 error
= user_path_at(AT_FDCWD
, filename
, lookup_flags
, &path
);
493 error
= path_permission(&path
, MAY_EXEC
| MAY_CHDIR
);
497 set_fs_pwd(current
->fs
, &path
);
501 if (retry_estale(error
, lookup_flags
)) {
502 lookup_flags
|= LOOKUP_REVAL
;
509 SYSCALL_DEFINE1(fchdir
, unsigned int, fd
)
511 struct fd f
= fdget_raw(fd
);
519 if (!d_can_lookup(f
.file
->f_path
.dentry
))
522 error
= file_permission(f
.file
, MAY_EXEC
| MAY_CHDIR
);
524 set_fs_pwd(current
->fs
, &f
.file
->f_path
);
531 SYSCALL_DEFINE1(chroot
, const char __user
*, filename
)
535 unsigned int lookup_flags
= LOOKUP_FOLLOW
| LOOKUP_DIRECTORY
;
537 error
= user_path_at(AT_FDCWD
, filename
, lookup_flags
, &path
);
541 error
= path_permission(&path
, MAY_EXEC
| MAY_CHDIR
);
546 if (!ns_capable(current_user_ns(), CAP_SYS_CHROOT
))
548 error
= security_path_chroot(&path
);
552 set_fs_root(current
->fs
, &path
);
556 if (retry_estale(error
, lookup_flags
)) {
557 lookup_flags
|= LOOKUP_REVAL
;
564 int chmod_common(const struct path
*path
, umode_t mode
)
566 struct inode
*inode
= path
->dentry
->d_inode
;
567 struct inode
*delegated_inode
= NULL
;
568 struct iattr newattrs
;
571 error
= mnt_want_write(path
->mnt
);
576 error
= security_path_chmod(path
, mode
);
579 newattrs
.ia_mode
= (mode
& S_IALLUGO
) | (inode
->i_mode
& ~S_IALLUGO
);
580 newattrs
.ia_valid
= ATTR_MODE
| ATTR_CTIME
;
581 error
= notify_change(mnt_user_ns(path
->mnt
), path
->dentry
,
582 &newattrs
, &delegated_inode
);
585 if (delegated_inode
) {
586 error
= break_deleg_wait(&delegated_inode
);
590 mnt_drop_write(path
->mnt
);
594 int vfs_fchmod(struct file
*file
, umode_t mode
)
597 return chmod_common(&file
->f_path
, mode
);
600 SYSCALL_DEFINE2(fchmod
, unsigned int, fd
, umode_t
, mode
)
602 struct fd f
= fdget(fd
);
606 err
= vfs_fchmod(f
.file
, mode
);
612 static int do_fchmodat(int dfd
, const char __user
*filename
, umode_t mode
)
616 unsigned int lookup_flags
= LOOKUP_FOLLOW
;
618 error
= user_path_at(dfd
, filename
, lookup_flags
, &path
);
620 error
= chmod_common(&path
, mode
);
622 if (retry_estale(error
, lookup_flags
)) {
623 lookup_flags
|= LOOKUP_REVAL
;
630 SYSCALL_DEFINE3(fchmodat
, int, dfd
, const char __user
*, filename
,
633 return do_fchmodat(dfd
, filename
, mode
);
636 SYSCALL_DEFINE2(chmod
, const char __user
*, filename
, umode_t
, mode
)
638 return do_fchmodat(AT_FDCWD
, filename
, mode
);
641 int chown_common(const struct path
*path
, uid_t user
, gid_t group
)
643 struct user_namespace
*mnt_userns
;
644 struct inode
*inode
= path
->dentry
->d_inode
;
645 struct inode
*delegated_inode
= NULL
;
647 struct iattr newattrs
;
651 uid
= make_kuid(current_user_ns(), user
);
652 gid
= make_kgid(current_user_ns(), group
);
654 mnt_userns
= mnt_user_ns(path
->mnt
);
655 uid
= kuid_from_mnt(mnt_userns
, uid
);
656 gid
= kgid_from_mnt(mnt_userns
, gid
);
659 newattrs
.ia_valid
= ATTR_CTIME
;
660 if (user
!= (uid_t
) -1) {
663 newattrs
.ia_valid
|= ATTR_UID
;
664 newattrs
.ia_uid
= uid
;
666 if (group
!= (gid_t
) -1) {
669 newattrs
.ia_valid
|= ATTR_GID
;
670 newattrs
.ia_gid
= gid
;
672 if (!S_ISDIR(inode
->i_mode
))
674 ATTR_KILL_SUID
| ATTR_KILL_SGID
| ATTR_KILL_PRIV
;
676 error
= security_path_chown(path
, uid
, gid
);
678 error
= notify_change(mnt_userns
, path
->dentry
, &newattrs
,
681 if (delegated_inode
) {
682 error
= break_deleg_wait(&delegated_inode
);
689 int do_fchownat(int dfd
, const char __user
*filename
, uid_t user
, gid_t group
,
696 if ((flag
& ~(AT_SYMLINK_NOFOLLOW
| AT_EMPTY_PATH
)) != 0)
699 lookup_flags
= (flag
& AT_SYMLINK_NOFOLLOW
) ? 0 : LOOKUP_FOLLOW
;
700 if (flag
& AT_EMPTY_PATH
)
701 lookup_flags
|= LOOKUP_EMPTY
;
703 error
= user_path_at(dfd
, filename
, lookup_flags
, &path
);
706 error
= mnt_want_write(path
.mnt
);
709 error
= chown_common(&path
, user
, group
);
710 mnt_drop_write(path
.mnt
);
713 if (retry_estale(error
, lookup_flags
)) {
714 lookup_flags
|= LOOKUP_REVAL
;
721 SYSCALL_DEFINE5(fchownat
, int, dfd
, const char __user
*, filename
, uid_t
, user
,
722 gid_t
, group
, int, flag
)
724 return do_fchownat(dfd
, filename
, user
, group
, flag
);
727 SYSCALL_DEFINE3(chown
, const char __user
*, filename
, uid_t
, user
, gid_t
, group
)
729 return do_fchownat(AT_FDCWD
, filename
, user
, group
, 0);
732 SYSCALL_DEFINE3(lchown
, const char __user
*, filename
, uid_t
, user
, gid_t
, group
)
734 return do_fchownat(AT_FDCWD
, filename
, user
, group
,
735 AT_SYMLINK_NOFOLLOW
);
738 int vfs_fchown(struct file
*file
, uid_t user
, gid_t group
)
742 error
= mnt_want_write_file(file
);
746 error
= chown_common(&file
->f_path
, user
, group
);
747 mnt_drop_write_file(file
);
751 int ksys_fchown(unsigned int fd
, uid_t user
, gid_t group
)
753 struct fd f
= fdget(fd
);
757 error
= vfs_fchown(f
.file
, user
, group
);
763 SYSCALL_DEFINE3(fchown
, unsigned int, fd
, uid_t
, user
, gid_t
, group
)
765 return ksys_fchown(fd
, user
, group
);
768 static int do_dentry_open(struct file
*f
,
770 int (*open
)(struct inode
*, struct file
*))
772 static const struct file_operations empty_fops
= {};
775 path_get(&f
->f_path
);
777 f
->f_mapping
= inode
->i_mapping
;
778 f
->f_wb_err
= filemap_sample_wb_err(f
->f_mapping
);
779 f
->f_sb_err
= file_sample_sb_err(f
);
781 if (unlikely(f
->f_flags
& O_PATH
)) {
782 f
->f_mode
= FMODE_PATH
| FMODE_OPENED
;
783 f
->f_op
= &empty_fops
;
787 if (f
->f_mode
& FMODE_WRITE
&& !special_file(inode
->i_mode
)) {
788 error
= get_write_access(inode
);
791 error
= __mnt_want_write(f
->f_path
.mnt
);
792 if (unlikely(error
)) {
793 put_write_access(inode
);
796 f
->f_mode
|= FMODE_WRITER
;
799 /* POSIX.1-2008/SUSv4 Section XSI 2.9.7 */
800 if (S_ISREG(inode
->i_mode
) || S_ISDIR(inode
->i_mode
))
801 f
->f_mode
|= FMODE_ATOMIC_POS
;
803 f
->f_op
= fops_get(inode
->i_fop
);
804 if (WARN_ON(!f
->f_op
)) {
809 error
= security_file_open(f
);
813 error
= break_lease(locks_inode(f
), f
->f_flags
);
817 /* normally all 3 are set; ->open() can clear them if needed */
818 f
->f_mode
|= FMODE_LSEEK
| FMODE_PREAD
| FMODE_PWRITE
;
820 open
= f
->f_op
->open
;
822 error
= open(inode
, f
);
826 f
->f_mode
|= FMODE_OPENED
;
827 if ((f
->f_mode
& (FMODE_READ
| FMODE_WRITE
)) == FMODE_READ
)
828 i_readcount_inc(inode
);
829 if ((f
->f_mode
& FMODE_READ
) &&
830 likely(f
->f_op
->read
|| f
->f_op
->read_iter
))
831 f
->f_mode
|= FMODE_CAN_READ
;
832 if ((f
->f_mode
& FMODE_WRITE
) &&
833 likely(f
->f_op
->write
|| f
->f_op
->write_iter
))
834 f
->f_mode
|= FMODE_CAN_WRITE
;
836 f
->f_write_hint
= WRITE_LIFE_NOT_SET
;
837 f
->f_flags
&= ~(O_CREAT
| O_EXCL
| O_NOCTTY
| O_TRUNC
);
839 file_ra_state_init(&f
->f_ra
, f
->f_mapping
->host
->i_mapping
);
841 /* NB: we're sure to have correct a_ops only after f_op->open */
842 if (f
->f_flags
& O_DIRECT
) {
843 if (!f
->f_mapping
->a_ops
|| !f
->f_mapping
->a_ops
->direct_IO
)
848 * XXX: Huge page cache doesn't support writing yet. Drop all page
849 * cache for this file before processing writes.
851 if (f
->f_mode
& FMODE_WRITE
) {
853 * Paired with smp_mb() in collapse_file() to ensure nr_thps
854 * is up to date and the update to i_writecount by
855 * get_write_access() is visible. Ensures subsequent insertion
856 * of THPs into the page cache will fail.
859 if (filemap_nr_thps(inode
->i_mapping
))
860 truncate_pagecache(inode
, 0);
866 if (WARN_ON_ONCE(error
> 0))
869 if (f
->f_mode
& FMODE_WRITER
) {
870 put_write_access(inode
);
871 __mnt_drop_write(f
->f_path
.mnt
);
874 path_put(&f
->f_path
);
875 f
->f_path
.mnt
= NULL
;
876 f
->f_path
.dentry
= NULL
;
882 * finish_open - finish opening a file
883 * @file: file pointer
884 * @dentry: pointer to dentry
885 * @open: open callback
886 * @opened: state of open
888 * This can be used to finish opening a file passed to i_op->atomic_open().
890 * If the open callback is set to NULL, then the standard f_op->open()
891 * filesystem callback is substituted.
893 * NB: the dentry reference is _not_ consumed. If, for example, the dentry is
894 * the return value of d_splice_alias(), then the caller needs to perform dput()
895 * on it after finish_open().
897 * Returns zero on success or -errno if the open failed.
899 int finish_open(struct file
*file
, struct dentry
*dentry
,
900 int (*open
)(struct inode
*, struct file
*))
902 BUG_ON(file
->f_mode
& FMODE_OPENED
); /* once it's opened, it's opened */
904 file
->f_path
.dentry
= dentry
;
905 return do_dentry_open(file
, d_backing_inode(dentry
), open
);
907 EXPORT_SYMBOL(finish_open
);
910 * finish_no_open - finish ->atomic_open() without opening the file
912 * @file: file pointer
913 * @dentry: dentry or NULL (as returned from ->lookup())
915 * This can be used to set the result of a successful lookup in ->atomic_open().
917 * NB: unlike finish_open() this function does consume the dentry reference and
918 * the caller need not dput() it.
920 * Returns "0" which must be the return value of ->atomic_open() after having
921 * called this function.
923 int finish_no_open(struct file
*file
, struct dentry
*dentry
)
925 file
->f_path
.dentry
= dentry
;
928 EXPORT_SYMBOL(finish_no_open
);
930 char *file_path(struct file
*filp
, char *buf
, int buflen
)
932 return d_path(&filp
->f_path
, buf
, buflen
);
934 EXPORT_SYMBOL(file_path
);
937 * vfs_open - open the file at the given path
938 * @path: path to open
939 * @file: newly allocated file with f_flag initialized
940 * @cred: credentials to use
942 int vfs_open(const struct path
*path
, struct file
*file
)
944 file
->f_path
= *path
;
945 return do_dentry_open(file
, d_backing_inode(path
->dentry
), NULL
);
948 struct file
*dentry_open(const struct path
*path
, int flags
,
949 const struct cred
*cred
)
954 validate_creds(cred
);
956 /* We must always pass in a valid mount pointer. */
959 f
= alloc_empty_file(flags
, cred
);
961 error
= vfs_open(path
, f
);
969 EXPORT_SYMBOL(dentry_open
);
971 struct file
*open_with_fake_path(const struct path
*path
, int flags
,
972 struct inode
*inode
, const struct cred
*cred
)
974 struct file
*f
= alloc_empty_file_noaccount(flags
, cred
);
979 error
= do_dentry_open(f
, inode
, NULL
);
987 EXPORT_SYMBOL(open_with_fake_path
);
989 #define WILL_CREATE(flags) (flags & (O_CREAT | __O_TMPFILE))
990 #define O_PATH_FLAGS (O_DIRECTORY | O_NOFOLLOW | O_PATH | O_CLOEXEC)
992 inline struct open_how
build_open_how(int flags
, umode_t mode
)
994 struct open_how how
= {
995 .flags
= flags
& VALID_OPEN_FLAGS
,
996 .mode
= mode
& S_IALLUGO
,
999 /* O_PATH beats everything else. */
1000 if (how
.flags
& O_PATH
)
1001 how
.flags
&= O_PATH_FLAGS
;
1002 /* Modes should only be set for create-like flags. */
1003 if (!WILL_CREATE(how
.flags
))
1008 inline int build_open_flags(const struct open_how
*how
, struct open_flags
*op
)
1010 u64 flags
= how
->flags
;
1011 u64 strip
= FMODE_NONOTIFY
| O_CLOEXEC
;
1012 int lookup_flags
= 0;
1013 int acc_mode
= ACC_MODE(flags
);
1015 BUILD_BUG_ON_MSG(upper_32_bits(VALID_OPEN_FLAGS
),
1016 "struct open_flags doesn't yet handle flags > 32 bits");
1019 * Strip flags that either shouldn't be set by userspace like
1020 * FMODE_NONOTIFY or that aren't relevant in determining struct
1021 * open_flags like O_CLOEXEC.
1026 * Older syscalls implicitly clear all of the invalid flags or argument
1027 * values before calling build_open_flags(), but openat2(2) checks all
1030 if (flags
& ~VALID_OPEN_FLAGS
)
1032 if (how
->resolve
& ~VALID_RESOLVE_FLAGS
)
1035 /* Scoping flags are mutually exclusive. */
1036 if ((how
->resolve
& RESOLVE_BENEATH
) && (how
->resolve
& RESOLVE_IN_ROOT
))
1039 /* Deal with the mode. */
1040 if (WILL_CREATE(flags
)) {
1041 if (how
->mode
& ~S_IALLUGO
)
1043 op
->mode
= how
->mode
| S_IFREG
;
1051 * In order to ensure programs get explicit errors when trying to use
1052 * O_TMPFILE on old kernels, O_TMPFILE is implemented such that it
1053 * looks like (O_DIRECTORY|O_RDWR & ~O_CREAT) to old kernels. But we
1054 * have to require userspace to explicitly set it.
1056 if (flags
& __O_TMPFILE
) {
1057 if ((flags
& O_TMPFILE_MASK
) != O_TMPFILE
)
1059 if (!(acc_mode
& MAY_WRITE
))
1062 if (flags
& O_PATH
) {
1063 /* O_PATH only permits certain other flags to be set. */
1064 if (flags
& ~O_PATH_FLAGS
)
1070 * O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only
1071 * check for O_DSYNC if the need any syncing at all we enforce it's
1072 * always set instead of having to deal with possibly weird behaviour
1073 * for malicious applications setting only __O_SYNC.
1075 if (flags
& __O_SYNC
)
1078 op
->open_flag
= flags
;
1080 /* O_TRUNC implies we need access checks for write permissions */
1081 if (flags
& O_TRUNC
)
1082 acc_mode
|= MAY_WRITE
;
1084 /* Allow the LSM permission hook to distinguish append
1085 access from general write access. */
1086 if (flags
& O_APPEND
)
1087 acc_mode
|= MAY_APPEND
;
1089 op
->acc_mode
= acc_mode
;
1091 op
->intent
= flags
& O_PATH
? 0 : LOOKUP_OPEN
;
1093 if (flags
& O_CREAT
) {
1094 op
->intent
|= LOOKUP_CREATE
;
1095 if (flags
& O_EXCL
) {
1096 op
->intent
|= LOOKUP_EXCL
;
1097 flags
|= O_NOFOLLOW
;
1101 if (flags
& O_DIRECTORY
)
1102 lookup_flags
|= LOOKUP_DIRECTORY
;
1103 if (!(flags
& O_NOFOLLOW
))
1104 lookup_flags
|= LOOKUP_FOLLOW
;
1106 if (how
->resolve
& RESOLVE_NO_XDEV
)
1107 lookup_flags
|= LOOKUP_NO_XDEV
;
1108 if (how
->resolve
& RESOLVE_NO_MAGICLINKS
)
1109 lookup_flags
|= LOOKUP_NO_MAGICLINKS
;
1110 if (how
->resolve
& RESOLVE_NO_SYMLINKS
)
1111 lookup_flags
|= LOOKUP_NO_SYMLINKS
;
1112 if (how
->resolve
& RESOLVE_BENEATH
)
1113 lookup_flags
|= LOOKUP_BENEATH
;
1114 if (how
->resolve
& RESOLVE_IN_ROOT
)
1115 lookup_flags
|= LOOKUP_IN_ROOT
;
1116 if (how
->resolve
& RESOLVE_CACHED
) {
1117 /* Don't bother even trying for create/truncate/tmpfile open */
1118 if (flags
& (O_TRUNC
| O_CREAT
| O_TMPFILE
))
1120 lookup_flags
|= LOOKUP_CACHED
;
1123 op
->lookup_flags
= lookup_flags
;
1128 * file_open_name - open file and return file pointer
1130 * @name: struct filename containing path to open
1131 * @flags: open flags as per the open(2) second argument
1132 * @mode: mode for the new file if O_CREAT is set, else ignored
1134 * This is the helper to open a file from kernelspace if you really
1135 * have to. But in generally you should not do this, so please move
1136 * along, nothing to see here..
1138 struct file
*file_open_name(struct filename
*name
, int flags
, umode_t mode
)
1140 struct open_flags op
;
1141 struct open_how how
= build_open_how(flags
, mode
);
1142 int err
= build_open_flags(&how
, &op
);
1144 return ERR_PTR(err
);
1145 return do_filp_open(AT_FDCWD
, name
, &op
);
1149 * filp_open - open file and return file pointer
1151 * @filename: path to open
1152 * @flags: open flags as per the open(2) second argument
1153 * @mode: mode for the new file if O_CREAT is set, else ignored
1155 * This is the helper to open a file from kernelspace if you really
1156 * have to. But in generally you should not do this, so please move
1157 * along, nothing to see here..
1159 struct file
*filp_open(const char *filename
, int flags
, umode_t mode
)
1161 struct filename
*name
= getname_kernel(filename
);
1162 struct file
*file
= ERR_CAST(name
);
1164 if (!IS_ERR(name
)) {
1165 file
= file_open_name(name
, flags
, mode
);
1170 EXPORT_SYMBOL(filp_open
);
1172 struct file
*file_open_root(const struct path
*root
,
1173 const char *filename
, int flags
, umode_t mode
)
1175 struct open_flags op
;
1176 struct open_how how
= build_open_how(flags
, mode
);
1177 int err
= build_open_flags(&how
, &op
);
1179 return ERR_PTR(err
);
1180 return do_file_open_root(root
, filename
, &op
);
1182 EXPORT_SYMBOL(file_open_root
);
1184 static long do_sys_openat2(int dfd
, const char __user
*filename
,
1185 struct open_how
*how
)
1187 struct open_flags op
;
1188 int fd
= build_open_flags(how
, &op
);
1189 struct filename
*tmp
;
1194 tmp
= getname(filename
);
1196 return PTR_ERR(tmp
);
1198 fd
= get_unused_fd_flags(how
->flags
);
1200 struct file
*f
= do_filp_open(dfd
, tmp
, &op
);
1213 long do_sys_open(int dfd
, const char __user
*filename
, int flags
, umode_t mode
)
1215 struct open_how how
= build_open_how(flags
, mode
);
1216 return do_sys_openat2(dfd
, filename
, &how
);
1220 SYSCALL_DEFINE3(open
, const char __user
*, filename
, int, flags
, umode_t
, mode
)
1222 if (force_o_largefile())
1223 flags
|= O_LARGEFILE
;
1224 return do_sys_open(AT_FDCWD
, filename
, flags
, mode
);
1227 SYSCALL_DEFINE4(openat
, int, dfd
, const char __user
*, filename
, int, flags
,
1230 if (force_o_largefile())
1231 flags
|= O_LARGEFILE
;
1232 return do_sys_open(dfd
, filename
, flags
, mode
);
1235 SYSCALL_DEFINE4(openat2
, int, dfd
, const char __user
*, filename
,
1236 struct open_how __user
*, how
, size_t, usize
)
1239 struct open_how tmp
;
1241 BUILD_BUG_ON(sizeof(struct open_how
) < OPEN_HOW_SIZE_VER0
);
1242 BUILD_BUG_ON(sizeof(struct open_how
) != OPEN_HOW_SIZE_LATEST
);
1244 if (unlikely(usize
< OPEN_HOW_SIZE_VER0
))
1247 err
= copy_struct_from_user(&tmp
, sizeof(tmp
), how
, usize
);
1251 /* O_LARGEFILE is only allowed for non-O_PATH. */
1252 if (!(tmp
.flags
& O_PATH
) && force_o_largefile())
1253 tmp
.flags
|= O_LARGEFILE
;
1255 return do_sys_openat2(dfd
, filename
, &tmp
);
1258 #ifdef CONFIG_COMPAT
1260 * Exactly like sys_open(), except that it doesn't set the
1263 COMPAT_SYSCALL_DEFINE3(open
, const char __user
*, filename
, int, flags
, umode_t
, mode
)
1265 return do_sys_open(AT_FDCWD
, filename
, flags
, mode
);
1269 * Exactly like sys_openat(), except that it doesn't set the
1272 COMPAT_SYSCALL_DEFINE4(openat
, int, dfd
, const char __user
*, filename
, int, flags
, umode_t
, mode
)
1274 return do_sys_open(dfd
, filename
, flags
, mode
);
1281 * For backward compatibility? Maybe this should be moved
1282 * into arch/i386 instead?
1284 SYSCALL_DEFINE2(creat
, const char __user
*, pathname
, umode_t
, mode
)
1286 int flags
= O_CREAT
| O_WRONLY
| O_TRUNC
;
1288 if (force_o_largefile())
1289 flags
|= O_LARGEFILE
;
1290 return do_sys_open(AT_FDCWD
, pathname
, flags
, mode
);
1295 * "id" is the POSIX thread ID. We use the
1296 * files pointer for this..
1298 int filp_close(struct file
*filp
, fl_owner_t id
)
1302 if (!file_count(filp
)) {
1303 printk(KERN_ERR
"VFS: Close: file count is 0\n");
1307 if (filp
->f_op
->flush
)
1308 retval
= filp
->f_op
->flush(filp
, id
);
1310 if (likely(!(filp
->f_mode
& FMODE_PATH
))) {
1311 dnotify_flush(filp
, id
);
1312 locks_remove_posix(filp
, id
);
1318 EXPORT_SYMBOL(filp_close
);
1321 * Careful here! We test whether the file pointer is NULL before
1322 * releasing the fd. This ensures that one clone task can't release
1323 * an fd while another clone is opening it.
1325 SYSCALL_DEFINE1(close
, unsigned int, fd
)
1327 int retval
= close_fd(fd
);
1329 /* can't restart close syscall because file table entry was cleared */
1330 if (unlikely(retval
== -ERESTARTSYS
||
1331 retval
== -ERESTARTNOINTR
||
1332 retval
== -ERESTARTNOHAND
||
1333 retval
== -ERESTART_RESTARTBLOCK
))
1340 * close_range() - Close all file descriptors in a given range.
1342 * @fd: starting file descriptor to close
1343 * @max_fd: last file descriptor to close
1344 * @flags: reserved for future extensions
1346 * This closes a range of file descriptors. All file descriptors
1347 * from @fd up to and including @max_fd are closed.
1348 * Currently, errors to close a given file descriptor are ignored.
1350 SYSCALL_DEFINE3(close_range
, unsigned int, fd
, unsigned int, max_fd
,
1351 unsigned int, flags
)
1353 return __close_range(fd
, max_fd
, flags
);
1357 * This routine simulates a hangup on the tty, to arrange that users
1358 * are given clean terminals at login time.
1360 SYSCALL_DEFINE0(vhangup
)
1362 if (capable(CAP_SYS_TTY_CONFIG
)) {
1370 * Called when an inode is about to be open.
1371 * We use this to disallow opening large files on 32bit systems if
1372 * the caller didn't specify O_LARGEFILE. On 64bit systems we force
1373 * on this flag in sys_open.
1375 int generic_file_open(struct inode
* inode
, struct file
* filp
)
1377 if (!(filp
->f_flags
& O_LARGEFILE
) && i_size_read(inode
) > MAX_NON_LFS
)
1382 EXPORT_SYMBOL(generic_file_open
);
1385 * This is used by subsystems that don't want seekable
1386 * file descriptors. The function is not supposed to ever fail, the only
1387 * reason it returns an 'int' and not 'void' is so that it can be plugged
1388 * directly into file_operations structure.
1390 int nonseekable_open(struct inode
*inode
, struct file
*filp
)
1392 filp
->f_mode
&= ~(FMODE_LSEEK
| FMODE_PREAD
| FMODE_PWRITE
);
1396 EXPORT_SYMBOL(nonseekable_open
);
1399 * stream_open is used by subsystems that want stream-like file descriptors.
1400 * Such file descriptors are not seekable and don't have notion of position
1401 * (file.f_pos is always 0 and ppos passed to .read()/.write() is always NULL).
1402 * Contrary to file descriptors of other regular files, .read() and .write()
1403 * can run simultaneously.
1405 * stream_open never fails and is marked to return int so that it could be
1406 * directly used as file_operations.open .
1408 int stream_open(struct inode
*inode
, struct file
*filp
)
1410 filp
->f_mode
&= ~(FMODE_LSEEK
| FMODE_PREAD
| FMODE_PWRITE
| FMODE_ATOMIC_POS
);
1411 filp
->f_mode
|= FMODE_STREAM
;
1415 EXPORT_SYMBOL(stream_open
);