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>
35 #include <linux/mnt_idmapping.h>
36 #include <linux/filelock.h>
40 int do_truncate(struct mnt_idmap
*idmap
, struct dentry
*dentry
,
41 loff_t length
, unsigned int time_attrs
, struct file
*filp
)
44 struct iattr newattrs
;
46 /* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */
50 newattrs
.ia_size
= length
;
51 newattrs
.ia_valid
= ATTR_SIZE
| time_attrs
;
53 newattrs
.ia_file
= filp
;
54 newattrs
.ia_valid
|= ATTR_FILE
;
57 /* Remove suid, sgid, and file capabilities on truncate too */
58 ret
= dentry_needs_remove_privs(idmap
, dentry
);
62 newattrs
.ia_valid
|= ret
| ATTR_FORCE
;
64 inode_lock(dentry
->d_inode
);
65 /* Note any delegations or leases have already been broken: */
66 ret
= notify_change(idmap
, dentry
, &newattrs
, NULL
);
67 inode_unlock(dentry
->d_inode
);
71 long vfs_truncate(const struct path
*path
, loff_t length
)
73 struct mnt_idmap
*idmap
;
77 inode
= path
->dentry
->d_inode
;
79 /* For directories it's -EISDIR, for other non-regulars - -EINVAL */
80 if (S_ISDIR(inode
->i_mode
))
82 if (!S_ISREG(inode
->i_mode
))
85 error
= mnt_want_write(path
->mnt
);
89 idmap
= mnt_idmap(path
->mnt
);
90 error
= inode_permission(idmap
, inode
, MAY_WRITE
);
92 goto mnt_drop_write_and_out
;
96 goto mnt_drop_write_and_out
;
98 error
= get_write_access(inode
);
100 goto mnt_drop_write_and_out
;
103 * Make sure that there are no leases. get_write_access() protects
104 * against the truncate racing with a lease-granting setlease().
106 error
= break_lease(inode
, O_WRONLY
);
108 goto put_write_and_out
;
110 error
= security_path_truncate(path
);
112 error
= do_truncate(idmap
, path
->dentry
, length
, 0, NULL
);
115 put_write_access(inode
);
116 mnt_drop_write_and_out
:
117 mnt_drop_write(path
->mnt
);
121 EXPORT_SYMBOL_GPL(vfs_truncate
);
123 long do_sys_truncate(const char __user
*pathname
, loff_t length
)
125 unsigned int lookup_flags
= LOOKUP_FOLLOW
;
129 if (length
< 0) /* sorry, but loff_t says... */
133 error
= user_path_at(AT_FDCWD
, pathname
, lookup_flags
, &path
);
135 error
= vfs_truncate(&path
, length
);
138 if (retry_estale(error
, lookup_flags
)) {
139 lookup_flags
|= LOOKUP_REVAL
;
145 SYSCALL_DEFINE2(truncate
, const char __user
*, path
, long, length
)
147 return do_sys_truncate(path
, length
);
151 COMPAT_SYSCALL_DEFINE2(truncate
, const char __user
*, path
, compat_off_t
, length
)
153 return do_sys_truncate(path
, length
);
157 long do_sys_ftruncate(unsigned int fd
, loff_t length
, int small
)
160 struct dentry
*dentry
;
172 /* explicitly opened as large or we are on 64-bit box */
173 if (f
.file
->f_flags
& O_LARGEFILE
)
176 dentry
= f
.file
->f_path
.dentry
;
177 inode
= dentry
->d_inode
;
179 if (!S_ISREG(inode
->i_mode
) || !(f
.file
->f_mode
& FMODE_WRITE
))
183 /* Cannot ftruncate over 2^31 bytes without large file support */
184 if (small
&& length
> MAX_NON_LFS
)
188 /* Check IS_APPEND on real upper inode */
189 if (IS_APPEND(file_inode(f
.file
)))
191 sb_start_write(inode
->i_sb
);
192 error
= security_file_truncate(f
.file
);
194 error
= do_truncate(file_mnt_idmap(f
.file
), dentry
, length
,
195 ATTR_MTIME
| ATTR_CTIME
, f
.file
);
196 sb_end_write(inode
->i_sb
);
203 SYSCALL_DEFINE2(ftruncate
, unsigned int, fd
, unsigned long, length
)
205 return do_sys_ftruncate(fd
, length
, 1);
209 COMPAT_SYSCALL_DEFINE2(ftruncate
, unsigned int, fd
, compat_ulong_t
, length
)
211 return do_sys_ftruncate(fd
, length
, 1);
215 /* LFS versions of truncate are only needed on 32 bit machines */
216 #if BITS_PER_LONG == 32
217 SYSCALL_DEFINE2(truncate64
, const char __user
*, path
, loff_t
, length
)
219 return do_sys_truncate(path
, length
);
222 SYSCALL_DEFINE2(ftruncate64
, unsigned int, fd
, loff_t
, length
)
224 return do_sys_ftruncate(fd
, length
, 0);
226 #endif /* BITS_PER_LONG == 32 */
228 #if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_TRUNCATE64)
229 COMPAT_SYSCALL_DEFINE3(truncate64
, const char __user
*, pathname
,
230 compat_arg_u64_dual(length
))
232 return ksys_truncate(pathname
, compat_arg_u64_glue(length
));
236 #if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_FTRUNCATE64)
237 COMPAT_SYSCALL_DEFINE3(ftruncate64
, unsigned int, fd
,
238 compat_arg_u64_dual(length
))
240 return ksys_ftruncate(fd
, compat_arg_u64_glue(length
));
244 int vfs_fallocate(struct file
*file
, int mode
, loff_t offset
, loff_t len
)
246 struct inode
*inode
= file_inode(file
);
249 if (offset
< 0 || len
<= 0)
252 /* Return error if mode is not supported */
253 if (mode
& ~FALLOC_FL_SUPPORTED_MASK
)
256 /* Punch hole and zero range are mutually exclusive */
257 if ((mode
& (FALLOC_FL_PUNCH_HOLE
| FALLOC_FL_ZERO_RANGE
)) ==
258 (FALLOC_FL_PUNCH_HOLE
| FALLOC_FL_ZERO_RANGE
))
261 /* Punch hole must have keep size set */
262 if ((mode
& FALLOC_FL_PUNCH_HOLE
) &&
263 !(mode
& FALLOC_FL_KEEP_SIZE
))
266 /* Collapse range should only be used exclusively. */
267 if ((mode
& FALLOC_FL_COLLAPSE_RANGE
) &&
268 (mode
& ~FALLOC_FL_COLLAPSE_RANGE
))
271 /* Insert range should only be used exclusively. */
272 if ((mode
& FALLOC_FL_INSERT_RANGE
) &&
273 (mode
& ~FALLOC_FL_INSERT_RANGE
))
276 /* Unshare range should only be used with allocate mode. */
277 if ((mode
& FALLOC_FL_UNSHARE_RANGE
) &&
278 (mode
& ~(FALLOC_FL_UNSHARE_RANGE
| FALLOC_FL_KEEP_SIZE
)))
281 if (!(file
->f_mode
& FMODE_WRITE
))
285 * We can only allow pure fallocate on append only files
287 if ((mode
& ~FALLOC_FL_KEEP_SIZE
) && IS_APPEND(inode
))
290 if (IS_IMMUTABLE(inode
))
294 * We cannot allow any fallocate operation on an active swapfile
296 if (IS_SWAPFILE(inode
))
300 * Revalidate the write permissions, in case security policy has
301 * changed since the files were opened.
303 ret
= security_file_permission(file
, MAY_WRITE
);
307 if (S_ISFIFO(inode
->i_mode
))
310 if (S_ISDIR(inode
->i_mode
))
313 if (!S_ISREG(inode
->i_mode
) && !S_ISBLK(inode
->i_mode
))
316 /* Check for wrap through zero too */
317 if (((offset
+ len
) > inode
->i_sb
->s_maxbytes
) || ((offset
+ len
) < 0))
320 if (!file
->f_op
->fallocate
)
323 file_start_write(file
);
324 ret
= file
->f_op
->fallocate(file
, mode
, offset
, len
);
327 * Create inotify and fanotify events.
329 * To keep the logic simple always create events if fallocate succeeds.
330 * This implies that events are even created if the file size remains
331 * unchanged, e.g. when using flag FALLOC_FL_KEEP_SIZE.
334 fsnotify_modify(file
);
336 file_end_write(file
);
339 EXPORT_SYMBOL_GPL(vfs_fallocate
);
341 int ksys_fallocate(int fd
, int mode
, loff_t offset
, loff_t len
)
343 struct fd f
= fdget(fd
);
347 error
= vfs_fallocate(f
.file
, mode
, offset
, len
);
353 SYSCALL_DEFINE4(fallocate
, int, fd
, int, mode
, loff_t
, offset
, loff_t
, len
)
355 return ksys_fallocate(fd
, mode
, offset
, len
);
358 #if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_FALLOCATE)
359 COMPAT_SYSCALL_DEFINE6(fallocate
, int, fd
, int, mode
, compat_arg_u64_dual(offset
),
360 compat_arg_u64_dual(len
))
362 return ksys_fallocate(fd
, mode
, compat_arg_u64_glue(offset
),
363 compat_arg_u64_glue(len
));
368 * access() needs to use the real uid/gid, not the effective uid/gid.
369 * We do this by temporarily clearing all FS-related capabilities and
370 * switching the fsuid/fsgid around to the real ones.
372 * Creating new credentials is expensive, so we try to skip doing it,
373 * which we can if the result would match what we already got.
375 static bool access_need_override_creds(int flags
)
377 const struct cred
*cred
;
379 if (flags
& AT_EACCESS
)
382 cred
= current_cred();
383 if (!uid_eq(cred
->fsuid
, cred
->uid
) ||
384 !gid_eq(cred
->fsgid
, cred
->gid
))
387 if (!issecure(SECURE_NO_SETUID_FIXUP
)) {
388 kuid_t root_uid
= make_kuid(cred
->user_ns
, 0);
389 if (!uid_eq(cred
->uid
, root_uid
)) {
390 if (!cap_isclear(cred
->cap_effective
))
393 if (!cap_isidentical(cred
->cap_effective
,
394 cred
->cap_permitted
))
402 static const struct cred
*access_override_creds(void)
404 const struct cred
*old_cred
;
405 struct cred
*override_cred
;
407 override_cred
= prepare_creds();
412 * XXX access_need_override_creds performs checks in hopes of skipping
413 * this work. Make sure it stays in sync if making any changes in this
417 override_cred
->fsuid
= override_cred
->uid
;
418 override_cred
->fsgid
= override_cred
->gid
;
420 if (!issecure(SECURE_NO_SETUID_FIXUP
)) {
421 /* Clear the capabilities if we switch to a non-root user */
422 kuid_t root_uid
= make_kuid(override_cred
->user_ns
, 0);
423 if (!uid_eq(override_cred
->uid
, root_uid
))
424 cap_clear(override_cred
->cap_effective
);
426 override_cred
->cap_effective
=
427 override_cred
->cap_permitted
;
431 * The new set of credentials can *only* be used in
432 * task-synchronous circumstances, and does not need
433 * RCU freeing, unless somebody then takes a separate
436 * NOTE! This is _only_ true because this credential
437 * is used purely for override_creds() that installs
438 * it as the subjective cred. Other threads will be
439 * accessing ->real_cred, not the subjective cred.
441 * If somebody _does_ make a copy of this (using the
442 * 'get_current_cred()' function), that will clear the
443 * non_rcu field, because now that other user may be
444 * expecting RCU freeing. But normal thread-synchronous
445 * cred accesses will keep things non-RCY.
447 override_cred
->non_rcu
= 1;
449 old_cred
= override_creds(override_cred
);
451 /* override_cred() gets its own ref */
452 put_cred(override_cred
);
457 static long do_faccessat(int dfd
, const char __user
*filename
, int mode
, int flags
)
462 unsigned int lookup_flags
= LOOKUP_FOLLOW
;
463 const struct cred
*old_cred
= NULL
;
465 if (mode
& ~S_IRWXO
) /* where's F_OK, X_OK, W_OK, R_OK? */
468 if (flags
& ~(AT_EACCESS
| AT_SYMLINK_NOFOLLOW
| AT_EMPTY_PATH
))
471 if (flags
& AT_SYMLINK_NOFOLLOW
)
472 lookup_flags
&= ~LOOKUP_FOLLOW
;
473 if (flags
& AT_EMPTY_PATH
)
474 lookup_flags
|= LOOKUP_EMPTY
;
476 if (access_need_override_creds(flags
)) {
477 old_cred
= access_override_creds();
483 res
= user_path_at(dfd
, filename
, lookup_flags
, &path
);
487 inode
= d_backing_inode(path
.dentry
);
489 if ((mode
& MAY_EXEC
) && S_ISREG(inode
->i_mode
)) {
491 * MAY_EXEC on regular files is denied if the fs is mounted
492 * with the "noexec" flag.
495 if (path_noexec(&path
))
496 goto out_path_release
;
499 res
= inode_permission(mnt_idmap(path
.mnt
), inode
, mode
| MAY_ACCESS
);
500 /* SuS v2 requires we report a read only fs too */
501 if (res
|| !(mode
& S_IWOTH
) || special_file(inode
->i_mode
))
502 goto out_path_release
;
504 * This is a rare case where using __mnt_is_readonly()
505 * is OK without a mnt_want/drop_write() pair. Since
506 * no actual write to the fs is performed here, we do
507 * not need to telegraph to that to anyone.
509 * By doing this, we accept that this access is
510 * inherently racy and know that the fs may change
511 * state before we even see this result.
513 if (__mnt_is_readonly(path
.mnt
))
518 if (retry_estale(res
, lookup_flags
)) {
519 lookup_flags
|= LOOKUP_REVAL
;
524 revert_creds(old_cred
);
529 SYSCALL_DEFINE3(faccessat
, int, dfd
, const char __user
*, filename
, int, mode
)
531 return do_faccessat(dfd
, filename
, mode
, 0);
534 SYSCALL_DEFINE4(faccessat2
, int, dfd
, const char __user
*, filename
, int, mode
,
537 return do_faccessat(dfd
, filename
, mode
, flags
);
540 SYSCALL_DEFINE2(access
, const char __user
*, filename
, int, mode
)
542 return do_faccessat(AT_FDCWD
, filename
, mode
, 0);
545 SYSCALL_DEFINE1(chdir
, const char __user
*, filename
)
549 unsigned int lookup_flags
= LOOKUP_FOLLOW
| LOOKUP_DIRECTORY
;
551 error
= user_path_at(AT_FDCWD
, filename
, lookup_flags
, &path
);
555 error
= path_permission(&path
, MAY_EXEC
| MAY_CHDIR
);
559 set_fs_pwd(current
->fs
, &path
);
563 if (retry_estale(error
, lookup_flags
)) {
564 lookup_flags
|= LOOKUP_REVAL
;
571 SYSCALL_DEFINE1(fchdir
, unsigned int, fd
)
573 struct fd f
= fdget_raw(fd
);
581 if (!d_can_lookup(f
.file
->f_path
.dentry
))
584 error
= file_permission(f
.file
, MAY_EXEC
| MAY_CHDIR
);
586 set_fs_pwd(current
->fs
, &f
.file
->f_path
);
593 SYSCALL_DEFINE1(chroot
, const char __user
*, filename
)
597 unsigned int lookup_flags
= LOOKUP_FOLLOW
| LOOKUP_DIRECTORY
;
599 error
= user_path_at(AT_FDCWD
, filename
, lookup_flags
, &path
);
603 error
= path_permission(&path
, MAY_EXEC
| MAY_CHDIR
);
608 if (!ns_capable(current_user_ns(), CAP_SYS_CHROOT
))
610 error
= security_path_chroot(&path
);
614 set_fs_root(current
->fs
, &path
);
618 if (retry_estale(error
, lookup_flags
)) {
619 lookup_flags
|= LOOKUP_REVAL
;
626 int chmod_common(const struct path
*path
, umode_t mode
)
628 struct inode
*inode
= path
->dentry
->d_inode
;
629 struct inode
*delegated_inode
= NULL
;
630 struct iattr newattrs
;
633 error
= mnt_want_write(path
->mnt
);
638 error
= security_path_chmod(path
, mode
);
641 newattrs
.ia_mode
= (mode
& S_IALLUGO
) | (inode
->i_mode
& ~S_IALLUGO
);
642 newattrs
.ia_valid
= ATTR_MODE
| ATTR_CTIME
;
643 error
= notify_change(mnt_idmap(path
->mnt
), path
->dentry
,
644 &newattrs
, &delegated_inode
);
647 if (delegated_inode
) {
648 error
= break_deleg_wait(&delegated_inode
);
652 mnt_drop_write(path
->mnt
);
656 int vfs_fchmod(struct file
*file
, umode_t mode
)
659 return chmod_common(&file
->f_path
, mode
);
662 SYSCALL_DEFINE2(fchmod
, unsigned int, fd
, umode_t
, mode
)
664 struct fd f
= fdget(fd
);
668 err
= vfs_fchmod(f
.file
, mode
);
674 static int do_fchmodat(int dfd
, const char __user
*filename
, umode_t mode
,
679 unsigned int lookup_flags
;
681 if (unlikely(flags
& ~(AT_SYMLINK_NOFOLLOW
| AT_EMPTY_PATH
)))
684 lookup_flags
= (flags
& AT_SYMLINK_NOFOLLOW
) ? 0 : LOOKUP_FOLLOW
;
685 if (flags
& AT_EMPTY_PATH
)
686 lookup_flags
|= LOOKUP_EMPTY
;
689 error
= user_path_at(dfd
, filename
, lookup_flags
, &path
);
691 error
= chmod_common(&path
, mode
);
693 if (retry_estale(error
, lookup_flags
)) {
694 lookup_flags
|= LOOKUP_REVAL
;
701 SYSCALL_DEFINE4(fchmodat2
, int, dfd
, const char __user
*, filename
,
702 umode_t
, mode
, unsigned int, flags
)
704 return do_fchmodat(dfd
, filename
, mode
, flags
);
707 SYSCALL_DEFINE3(fchmodat
, int, dfd
, const char __user
*, filename
,
710 return do_fchmodat(dfd
, filename
, mode
, 0);
713 SYSCALL_DEFINE2(chmod
, const char __user
*, filename
, umode_t
, mode
)
715 return do_fchmodat(AT_FDCWD
, filename
, mode
, 0);
719 * Check whether @kuid is valid and if so generate and set vfsuid_t in
722 * Return: true if @kuid is valid, false if not.
724 static inline bool setattr_vfsuid(struct iattr
*attr
, kuid_t kuid
)
726 if (!uid_valid(kuid
))
728 attr
->ia_valid
|= ATTR_UID
;
729 attr
->ia_vfsuid
= VFSUIDT_INIT(kuid
);
734 * Check whether @kgid is valid and if so generate and set vfsgid_t in
737 * Return: true if @kgid is valid, false if not.
739 static inline bool setattr_vfsgid(struct iattr
*attr
, kgid_t kgid
)
741 if (!gid_valid(kgid
))
743 attr
->ia_valid
|= ATTR_GID
;
744 attr
->ia_vfsgid
= VFSGIDT_INIT(kgid
);
748 int chown_common(const struct path
*path
, uid_t user
, gid_t group
)
750 struct mnt_idmap
*idmap
;
751 struct user_namespace
*fs_userns
;
752 struct inode
*inode
= path
->dentry
->d_inode
;
753 struct inode
*delegated_inode
= NULL
;
755 struct iattr newattrs
;
759 uid
= make_kuid(current_user_ns(), user
);
760 gid
= make_kgid(current_user_ns(), group
);
762 idmap
= mnt_idmap(path
->mnt
);
763 fs_userns
= i_user_ns(inode
);
766 newattrs
.ia_vfsuid
= INVALID_VFSUID
;
767 newattrs
.ia_vfsgid
= INVALID_VFSGID
;
768 newattrs
.ia_valid
= ATTR_CTIME
;
769 if ((user
!= (uid_t
)-1) && !setattr_vfsuid(&newattrs
, uid
))
771 if ((group
!= (gid_t
)-1) && !setattr_vfsgid(&newattrs
, gid
))
774 if (!S_ISDIR(inode
->i_mode
))
775 newattrs
.ia_valid
|= ATTR_KILL_SUID
| ATTR_KILL_PRIV
|
776 setattr_should_drop_sgid(idmap
, inode
);
777 /* Continue to send actual fs values, not the mount values. */
778 error
= security_path_chown(
780 from_vfsuid(idmap
, fs_userns
, newattrs
.ia_vfsuid
),
781 from_vfsgid(idmap
, fs_userns
, newattrs
.ia_vfsgid
));
783 error
= notify_change(idmap
, path
->dentry
, &newattrs
,
786 if (delegated_inode
) {
787 error
= break_deleg_wait(&delegated_inode
);
794 int do_fchownat(int dfd
, const char __user
*filename
, uid_t user
, gid_t group
,
801 if ((flag
& ~(AT_SYMLINK_NOFOLLOW
| AT_EMPTY_PATH
)) != 0)
804 lookup_flags
= (flag
& AT_SYMLINK_NOFOLLOW
) ? 0 : LOOKUP_FOLLOW
;
805 if (flag
& AT_EMPTY_PATH
)
806 lookup_flags
|= LOOKUP_EMPTY
;
808 error
= user_path_at(dfd
, filename
, lookup_flags
, &path
);
811 error
= mnt_want_write(path
.mnt
);
814 error
= chown_common(&path
, user
, group
);
815 mnt_drop_write(path
.mnt
);
818 if (retry_estale(error
, lookup_flags
)) {
819 lookup_flags
|= LOOKUP_REVAL
;
826 SYSCALL_DEFINE5(fchownat
, int, dfd
, const char __user
*, filename
, uid_t
, user
,
827 gid_t
, group
, int, flag
)
829 return do_fchownat(dfd
, filename
, user
, group
, flag
);
832 SYSCALL_DEFINE3(chown
, const char __user
*, filename
, uid_t
, user
, gid_t
, group
)
834 return do_fchownat(AT_FDCWD
, filename
, user
, group
, 0);
837 SYSCALL_DEFINE3(lchown
, const char __user
*, filename
, uid_t
, user
, gid_t
, group
)
839 return do_fchownat(AT_FDCWD
, filename
, user
, group
,
840 AT_SYMLINK_NOFOLLOW
);
843 int vfs_fchown(struct file
*file
, uid_t user
, gid_t group
)
847 error
= mnt_want_write_file(file
);
851 error
= chown_common(&file
->f_path
, user
, group
);
852 mnt_drop_write_file(file
);
856 int ksys_fchown(unsigned int fd
, uid_t user
, gid_t group
)
858 struct fd f
= fdget(fd
);
862 error
= vfs_fchown(f
.file
, user
, group
);
868 SYSCALL_DEFINE3(fchown
, unsigned int, fd
, uid_t
, user
, gid_t
, group
)
870 return ksys_fchown(fd
, user
, group
);
873 static int do_dentry_open(struct file
*f
,
875 int (*open
)(struct inode
*, struct file
*))
877 static const struct file_operations empty_fops
= {};
880 path_get(&f
->f_path
);
882 f
->f_mapping
= inode
->i_mapping
;
883 f
->f_wb_err
= filemap_sample_wb_err(f
->f_mapping
);
884 f
->f_sb_err
= file_sample_sb_err(f
);
886 if (unlikely(f
->f_flags
& O_PATH
)) {
887 f
->f_mode
= FMODE_PATH
| FMODE_OPENED
;
888 f
->f_op
= &empty_fops
;
892 if ((f
->f_mode
& (FMODE_READ
| FMODE_WRITE
)) == FMODE_READ
) {
893 i_readcount_inc(inode
);
894 } else if (f
->f_mode
& FMODE_WRITE
&& !special_file(inode
->i_mode
)) {
895 error
= get_write_access(inode
);
898 error
= __mnt_want_write(f
->f_path
.mnt
);
899 if (unlikely(error
)) {
900 put_write_access(inode
);
903 f
->f_mode
|= FMODE_WRITER
;
906 /* POSIX.1-2008/SUSv4 Section XSI 2.9.7 */
907 if (S_ISREG(inode
->i_mode
) || S_ISDIR(inode
->i_mode
))
908 f
->f_mode
|= FMODE_ATOMIC_POS
;
910 f
->f_op
= fops_get(inode
->i_fop
);
911 if (WARN_ON(!f
->f_op
)) {
916 error
= security_file_open(f
);
920 error
= break_lease(file_inode(f
), f
->f_flags
);
924 /* normally all 3 are set; ->open() can clear them if needed */
925 f
->f_mode
|= FMODE_LSEEK
| FMODE_PREAD
| FMODE_PWRITE
;
927 open
= f
->f_op
->open
;
929 error
= open(inode
, f
);
933 f
->f_mode
|= FMODE_OPENED
;
934 if ((f
->f_mode
& FMODE_READ
) &&
935 likely(f
->f_op
->read
|| f
->f_op
->read_iter
))
936 f
->f_mode
|= FMODE_CAN_READ
;
937 if ((f
->f_mode
& FMODE_WRITE
) &&
938 likely(f
->f_op
->write
|| f
->f_op
->write_iter
))
939 f
->f_mode
|= FMODE_CAN_WRITE
;
940 if ((f
->f_mode
& FMODE_LSEEK
) && !f
->f_op
->llseek
)
941 f
->f_mode
&= ~FMODE_LSEEK
;
942 if (f
->f_mapping
->a_ops
&& f
->f_mapping
->a_ops
->direct_IO
)
943 f
->f_mode
|= FMODE_CAN_ODIRECT
;
945 f
->f_flags
&= ~(O_CREAT
| O_EXCL
| O_NOCTTY
| O_TRUNC
);
946 f
->f_iocb_flags
= iocb_flags(f
);
948 file_ra_state_init(&f
->f_ra
, f
->f_mapping
->host
->i_mapping
);
950 if ((f
->f_flags
& O_DIRECT
) && !(f
->f_mode
& FMODE_CAN_ODIRECT
))
954 * XXX: Huge page cache doesn't support writing yet. Drop all page
955 * cache for this file before processing writes.
957 if (f
->f_mode
& FMODE_WRITE
) {
959 * Paired with smp_mb() in collapse_file() to ensure nr_thps
960 * is up to date and the update to i_writecount by
961 * get_write_access() is visible. Ensures subsequent insertion
962 * of THPs into the page cache will fail.
965 if (filemap_nr_thps(inode
->i_mapping
)) {
966 struct address_space
*mapping
= inode
->i_mapping
;
968 filemap_invalidate_lock(inode
->i_mapping
);
970 * unmap_mapping_range just need to be called once
971 * here, because the private pages is not need to be
972 * unmapped mapping (e.g. data segment of dynamic
973 * shared libraries here).
975 unmap_mapping_range(mapping
, 0, 0, 0);
976 truncate_inode_pages(mapping
, 0);
977 filemap_invalidate_unlock(inode
->i_mapping
);
982 * Once we return a file with FMODE_OPENED, __fput() will call
983 * fsnotify_close(), so we need fsnotify_open() here for symmetry.
989 if (WARN_ON_ONCE(error
> 0))
994 path_put(&f
->f_path
);
995 f
->f_path
.mnt
= NULL
;
996 f
->f_path
.dentry
= NULL
;
1002 * finish_open - finish opening a file
1003 * @file: file pointer
1004 * @dentry: pointer to dentry
1005 * @open: open callback
1007 * This can be used to finish opening a file passed to i_op->atomic_open().
1009 * If the open callback is set to NULL, then the standard f_op->open()
1010 * filesystem callback is substituted.
1012 * NB: the dentry reference is _not_ consumed. If, for example, the dentry is
1013 * the return value of d_splice_alias(), then the caller needs to perform dput()
1014 * on it after finish_open().
1016 * Returns zero on success or -errno if the open failed.
1018 int finish_open(struct file
*file
, struct dentry
*dentry
,
1019 int (*open
)(struct inode
*, struct file
*))
1021 BUG_ON(file
->f_mode
& FMODE_OPENED
); /* once it's opened, it's opened */
1023 file
->f_path
.dentry
= dentry
;
1024 return do_dentry_open(file
, d_backing_inode(dentry
), open
);
1026 EXPORT_SYMBOL(finish_open
);
1029 * finish_no_open - finish ->atomic_open() without opening the file
1031 * @file: file pointer
1032 * @dentry: dentry or NULL (as returned from ->lookup())
1034 * This can be used to set the result of a successful lookup in ->atomic_open().
1036 * NB: unlike finish_open() this function does consume the dentry reference and
1037 * the caller need not dput() it.
1039 * Returns "0" which must be the return value of ->atomic_open() after having
1040 * called this function.
1042 int finish_no_open(struct file
*file
, struct dentry
*dentry
)
1044 file
->f_path
.dentry
= dentry
;
1047 EXPORT_SYMBOL(finish_no_open
);
1049 char *file_path(struct file
*filp
, char *buf
, int buflen
)
1051 return d_path(&filp
->f_path
, buf
, buflen
);
1053 EXPORT_SYMBOL(file_path
);
1056 * vfs_open - open the file at the given path
1057 * @path: path to open
1058 * @file: newly allocated file with f_flag initialized
1060 int vfs_open(const struct path
*path
, struct file
*file
)
1062 file
->f_path
= *path
;
1063 return do_dentry_open(file
, d_backing_inode(path
->dentry
), NULL
);
1066 struct file
*dentry_open(const struct path
*path
, int flags
,
1067 const struct cred
*cred
)
1072 validate_creds(cred
);
1074 /* We must always pass in a valid mount pointer. */
1077 f
= alloc_empty_file(flags
, cred
);
1079 error
= vfs_open(path
, f
);
1087 EXPORT_SYMBOL(dentry_open
);
1090 * dentry_create - Create and open a file
1091 * @path: path to create
1093 * @mode: mode bits for new file
1094 * @cred: credentials to use
1096 * Caller must hold the parent directory's lock, and have prepared
1097 * a negative dentry, placed in @path->dentry, for the new file.
1099 * Caller sets @path->mnt to the vfsmount of the filesystem where
1100 * the new file is to be created. The parent directory and the
1101 * negative dentry must reside on the same filesystem instance.
1103 * On success, returns a "struct file *". Otherwise a ERR_PTR
1106 struct file
*dentry_create(const struct path
*path
, int flags
, umode_t mode
,
1107 const struct cred
*cred
)
1112 validate_creds(cred
);
1113 f
= alloc_empty_file(flags
, cred
);
1117 error
= vfs_create(mnt_idmap(path
->mnt
),
1118 d_inode(path
->dentry
->d_parent
),
1119 path
->dentry
, mode
, true);
1121 error
= vfs_open(path
, f
);
1123 if (unlikely(error
)) {
1125 return ERR_PTR(error
);
1129 EXPORT_SYMBOL(dentry_create
);
1132 * kernel_file_open - open a file for kernel internal use
1133 * @path: path of the file to open
1134 * @flags: open flags
1136 * @cred: credentials for open
1138 * Open a file for use by in-kernel consumers. The file is not accounted
1139 * against nr_files and must not be installed into the file descriptor
1142 * Return: Opened file on success, an error pointer on failure.
1144 struct file
*kernel_file_open(const struct path
*path
, int flags
,
1145 struct inode
*inode
, const struct cred
*cred
)
1150 f
= alloc_empty_file_noaccount(flags
, cred
);
1155 error
= do_dentry_open(f
, inode
, NULL
);
1162 EXPORT_SYMBOL_GPL(kernel_file_open
);
1165 * backing_file_open - open a backing file for kernel internal use
1166 * @path: path of the file to open
1167 * @flags: open flags
1168 * @real_path: path of the backing file
1169 * @cred: credentials for open
1171 * Open a backing file for a stackable filesystem (e.g., overlayfs).
1172 * @path may be on the stackable filesystem and backing inode on the
1173 * underlying filesystem. In this case, we want to be able to return
1174 * the @real_path of the backing inode. This is done by embedding the
1175 * returned file into a container structure that also stores the path of
1176 * the backing inode on the underlying filesystem, which can be
1177 * retrieved using backing_file_real_path().
1179 struct file
*backing_file_open(const struct path
*path
, int flags
,
1180 const struct path
*real_path
,
1181 const struct cred
*cred
)
1186 f
= alloc_empty_backing_file(flags
, cred
);
1191 path_get(real_path
);
1192 *backing_file_real_path(f
) = *real_path
;
1193 error
= do_dentry_open(f
, d_inode(real_path
->dentry
), NULL
);
1201 EXPORT_SYMBOL_GPL(backing_file_open
);
1203 #define WILL_CREATE(flags) (flags & (O_CREAT | __O_TMPFILE))
1204 #define O_PATH_FLAGS (O_DIRECTORY | O_NOFOLLOW | O_PATH | O_CLOEXEC)
1206 inline struct open_how
build_open_how(int flags
, umode_t mode
)
1208 struct open_how how
= {
1209 .flags
= flags
& VALID_OPEN_FLAGS
,
1210 .mode
= mode
& S_IALLUGO
,
1213 /* O_PATH beats everything else. */
1214 if (how
.flags
& O_PATH
)
1215 how
.flags
&= O_PATH_FLAGS
;
1216 /* Modes should only be set for create-like flags. */
1217 if (!WILL_CREATE(how
.flags
))
1222 inline int build_open_flags(const struct open_how
*how
, struct open_flags
*op
)
1224 u64 flags
= how
->flags
;
1225 u64 strip
= __FMODE_NONOTIFY
| O_CLOEXEC
;
1226 int lookup_flags
= 0;
1227 int acc_mode
= ACC_MODE(flags
);
1229 BUILD_BUG_ON_MSG(upper_32_bits(VALID_OPEN_FLAGS
),
1230 "struct open_flags doesn't yet handle flags > 32 bits");
1233 * Strip flags that either shouldn't be set by userspace like
1234 * FMODE_NONOTIFY or that aren't relevant in determining struct
1235 * open_flags like O_CLOEXEC.
1240 * Older syscalls implicitly clear all of the invalid flags or argument
1241 * values before calling build_open_flags(), but openat2(2) checks all
1244 if (flags
& ~VALID_OPEN_FLAGS
)
1246 if (how
->resolve
& ~VALID_RESOLVE_FLAGS
)
1249 /* Scoping flags are mutually exclusive. */
1250 if ((how
->resolve
& RESOLVE_BENEATH
) && (how
->resolve
& RESOLVE_IN_ROOT
))
1253 /* Deal with the mode. */
1254 if (WILL_CREATE(flags
)) {
1255 if (how
->mode
& ~S_IALLUGO
)
1257 op
->mode
= how
->mode
| S_IFREG
;
1265 * Block bugs where O_DIRECTORY | O_CREAT created regular files.
1266 * Note, that blocking O_DIRECTORY | O_CREAT here also protects
1267 * O_TMPFILE below which requires O_DIRECTORY being raised.
1269 if ((flags
& (O_DIRECTORY
| O_CREAT
)) == (O_DIRECTORY
| O_CREAT
))
1272 /* Now handle the creative implementation of O_TMPFILE. */
1273 if (flags
& __O_TMPFILE
) {
1275 * In order to ensure programs get explicit errors when trying
1276 * to use O_TMPFILE on old kernels we enforce that O_DIRECTORY
1277 * is raised alongside __O_TMPFILE.
1279 if (!(flags
& O_DIRECTORY
))
1281 if (!(acc_mode
& MAY_WRITE
))
1284 if (flags
& O_PATH
) {
1285 /* O_PATH only permits certain other flags to be set. */
1286 if (flags
& ~O_PATH_FLAGS
)
1292 * O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only
1293 * check for O_DSYNC if the need any syncing at all we enforce it's
1294 * always set instead of having to deal with possibly weird behaviour
1295 * for malicious applications setting only __O_SYNC.
1297 if (flags
& __O_SYNC
)
1300 op
->open_flag
= flags
;
1302 /* O_TRUNC implies we need access checks for write permissions */
1303 if (flags
& O_TRUNC
)
1304 acc_mode
|= MAY_WRITE
;
1306 /* Allow the LSM permission hook to distinguish append
1307 access from general write access. */
1308 if (flags
& O_APPEND
)
1309 acc_mode
|= MAY_APPEND
;
1311 op
->acc_mode
= acc_mode
;
1313 op
->intent
= flags
& O_PATH
? 0 : LOOKUP_OPEN
;
1315 if (flags
& O_CREAT
) {
1316 op
->intent
|= LOOKUP_CREATE
;
1317 if (flags
& O_EXCL
) {
1318 op
->intent
|= LOOKUP_EXCL
;
1319 flags
|= O_NOFOLLOW
;
1323 if (flags
& O_DIRECTORY
)
1324 lookup_flags
|= LOOKUP_DIRECTORY
;
1325 if (!(flags
& O_NOFOLLOW
))
1326 lookup_flags
|= LOOKUP_FOLLOW
;
1328 if (how
->resolve
& RESOLVE_NO_XDEV
)
1329 lookup_flags
|= LOOKUP_NO_XDEV
;
1330 if (how
->resolve
& RESOLVE_NO_MAGICLINKS
)
1331 lookup_flags
|= LOOKUP_NO_MAGICLINKS
;
1332 if (how
->resolve
& RESOLVE_NO_SYMLINKS
)
1333 lookup_flags
|= LOOKUP_NO_SYMLINKS
;
1334 if (how
->resolve
& RESOLVE_BENEATH
)
1335 lookup_flags
|= LOOKUP_BENEATH
;
1336 if (how
->resolve
& RESOLVE_IN_ROOT
)
1337 lookup_flags
|= LOOKUP_IN_ROOT
;
1338 if (how
->resolve
& RESOLVE_CACHED
) {
1339 /* Don't bother even trying for create/truncate/tmpfile open */
1340 if (flags
& (O_TRUNC
| O_CREAT
| __O_TMPFILE
))
1342 lookup_flags
|= LOOKUP_CACHED
;
1345 op
->lookup_flags
= lookup_flags
;
1350 * file_open_name - open file and return file pointer
1352 * @name: struct filename containing path to open
1353 * @flags: open flags as per the open(2) second argument
1354 * @mode: mode for the new file if O_CREAT is set, else ignored
1356 * This is the helper to open a file from kernelspace if you really
1357 * have to. But in generally you should not do this, so please move
1358 * along, nothing to see here..
1360 struct file
*file_open_name(struct filename
*name
, int flags
, umode_t mode
)
1362 struct open_flags op
;
1363 struct open_how how
= build_open_how(flags
, mode
);
1364 int err
= build_open_flags(&how
, &op
);
1366 return ERR_PTR(err
);
1367 return do_filp_open(AT_FDCWD
, name
, &op
);
1371 * filp_open - open file and return file pointer
1373 * @filename: path to open
1374 * @flags: open flags as per the open(2) second argument
1375 * @mode: mode for the new file if O_CREAT is set, else ignored
1377 * This is the helper to open a file from kernelspace if you really
1378 * have to. But in generally you should not do this, so please move
1379 * along, nothing to see here..
1381 struct file
*filp_open(const char *filename
, int flags
, umode_t mode
)
1383 struct filename
*name
= getname_kernel(filename
);
1384 struct file
*file
= ERR_CAST(name
);
1386 if (!IS_ERR(name
)) {
1387 file
= file_open_name(name
, flags
, mode
);
1392 EXPORT_SYMBOL(filp_open
);
1394 struct file
*file_open_root(const struct path
*root
,
1395 const char *filename
, int flags
, umode_t mode
)
1397 struct open_flags op
;
1398 struct open_how how
= build_open_how(flags
, mode
);
1399 int err
= build_open_flags(&how
, &op
);
1401 return ERR_PTR(err
);
1402 return do_file_open_root(root
, filename
, &op
);
1404 EXPORT_SYMBOL(file_open_root
);
1406 static long do_sys_openat2(int dfd
, const char __user
*filename
,
1407 struct open_how
*how
)
1409 struct open_flags op
;
1410 int fd
= build_open_flags(how
, &op
);
1411 struct filename
*tmp
;
1416 tmp
= getname(filename
);
1418 return PTR_ERR(tmp
);
1420 fd
= get_unused_fd_flags(how
->flags
);
1422 struct file
*f
= do_filp_open(dfd
, tmp
, &op
);
1434 long do_sys_open(int dfd
, const char __user
*filename
, int flags
, umode_t mode
)
1436 struct open_how how
= build_open_how(flags
, mode
);
1437 return do_sys_openat2(dfd
, filename
, &how
);
1441 SYSCALL_DEFINE3(open
, const char __user
*, filename
, int, flags
, umode_t
, mode
)
1443 if (force_o_largefile())
1444 flags
|= O_LARGEFILE
;
1445 return do_sys_open(AT_FDCWD
, filename
, flags
, mode
);
1448 SYSCALL_DEFINE4(openat
, int, dfd
, const char __user
*, filename
, int, flags
,
1451 if (force_o_largefile())
1452 flags
|= O_LARGEFILE
;
1453 return do_sys_open(dfd
, filename
, flags
, mode
);
1456 SYSCALL_DEFINE4(openat2
, int, dfd
, const char __user
*, filename
,
1457 struct open_how __user
*, how
, size_t, usize
)
1460 struct open_how tmp
;
1462 BUILD_BUG_ON(sizeof(struct open_how
) < OPEN_HOW_SIZE_VER0
);
1463 BUILD_BUG_ON(sizeof(struct open_how
) != OPEN_HOW_SIZE_LATEST
);
1465 if (unlikely(usize
< OPEN_HOW_SIZE_VER0
))
1468 err
= copy_struct_from_user(&tmp
, sizeof(tmp
), how
, usize
);
1472 audit_openat2_how(&tmp
);
1474 /* O_LARGEFILE is only allowed for non-O_PATH. */
1475 if (!(tmp
.flags
& O_PATH
) && force_o_largefile())
1476 tmp
.flags
|= O_LARGEFILE
;
1478 return do_sys_openat2(dfd
, filename
, &tmp
);
1481 #ifdef CONFIG_COMPAT
1483 * Exactly like sys_open(), except that it doesn't set the
1486 COMPAT_SYSCALL_DEFINE3(open
, const char __user
*, filename
, int, flags
, umode_t
, mode
)
1488 return do_sys_open(AT_FDCWD
, filename
, flags
, mode
);
1492 * Exactly like sys_openat(), except that it doesn't set the
1495 COMPAT_SYSCALL_DEFINE4(openat
, int, dfd
, const char __user
*, filename
, int, flags
, umode_t
, mode
)
1497 return do_sys_open(dfd
, filename
, flags
, mode
);
1504 * For backward compatibility? Maybe this should be moved
1505 * into arch/i386 instead?
1507 SYSCALL_DEFINE2(creat
, const char __user
*, pathname
, umode_t
, mode
)
1509 int flags
= O_CREAT
| O_WRONLY
| O_TRUNC
;
1511 if (force_o_largefile())
1512 flags
|= O_LARGEFILE
;
1513 return do_sys_open(AT_FDCWD
, pathname
, flags
, mode
);
1518 * "id" is the POSIX thread ID. We use the
1519 * files pointer for this..
1521 static int filp_flush(struct file
*filp
, fl_owner_t id
)
1525 if (CHECK_DATA_CORRUPTION(file_count(filp
) == 0,
1526 "VFS: Close: file count is 0 (f_op=%ps)",
1531 if (filp
->f_op
->flush
)
1532 retval
= filp
->f_op
->flush(filp
, id
);
1534 if (likely(!(filp
->f_mode
& FMODE_PATH
))) {
1535 dnotify_flush(filp
, id
);
1536 locks_remove_posix(filp
, id
);
1541 int filp_close(struct file
*filp
, fl_owner_t id
)
1545 retval
= filp_flush(filp
, id
);
1550 EXPORT_SYMBOL(filp_close
);
1553 * Careful here! We test whether the file pointer is NULL before
1554 * releasing the fd. This ensures that one clone task can't release
1555 * an fd while another clone is opening it.
1557 SYSCALL_DEFINE1(close
, unsigned int, fd
)
1562 file
= close_fd_get_file(fd
);
1566 retval
= filp_flush(file
, current
->files
);
1569 * We're returning to user space. Don't bother
1570 * with any delayed fput() cases.
1574 /* can't restart close syscall because file table entry was cleared */
1575 if (unlikely(retval
== -ERESTARTSYS
||
1576 retval
== -ERESTARTNOINTR
||
1577 retval
== -ERESTARTNOHAND
||
1578 retval
== -ERESTART_RESTARTBLOCK
))
1585 * sys_close_range() - Close all file descriptors in a given range.
1587 * @fd: starting file descriptor to close
1588 * @max_fd: last file descriptor to close
1589 * @flags: reserved for future extensions
1591 * This closes a range of file descriptors. All file descriptors
1592 * from @fd up to and including @max_fd are closed.
1593 * Currently, errors to close a given file descriptor are ignored.
1595 SYSCALL_DEFINE3(close_range
, unsigned int, fd
, unsigned int, max_fd
,
1596 unsigned int, flags
)
1598 return __close_range(fd
, max_fd
, flags
);
1602 * This routine simulates a hangup on the tty, to arrange that users
1603 * are given clean terminals at login time.
1605 SYSCALL_DEFINE0(vhangup
)
1607 if (capable(CAP_SYS_TTY_CONFIG
)) {
1615 * Called when an inode is about to be open.
1616 * We use this to disallow opening large files on 32bit systems if
1617 * the caller didn't specify O_LARGEFILE. On 64bit systems we force
1618 * on this flag in sys_open.
1620 int generic_file_open(struct inode
* inode
, struct file
* filp
)
1622 if (!(filp
->f_flags
& O_LARGEFILE
) && i_size_read(inode
) > MAX_NON_LFS
)
1627 EXPORT_SYMBOL(generic_file_open
);
1630 * This is used by subsystems that don't want seekable
1631 * file descriptors. The function is not supposed to ever fail, the only
1632 * reason it returns an 'int' and not 'void' is so that it can be plugged
1633 * directly into file_operations structure.
1635 int nonseekable_open(struct inode
*inode
, struct file
*filp
)
1637 filp
->f_mode
&= ~(FMODE_LSEEK
| FMODE_PREAD
| FMODE_PWRITE
);
1641 EXPORT_SYMBOL(nonseekable_open
);
1644 * stream_open is used by subsystems that want stream-like file descriptors.
1645 * Such file descriptors are not seekable and don't have notion of position
1646 * (file.f_pos is always 0 and ppos passed to .read()/.write() is always NULL).
1647 * Contrary to file descriptors of other regular files, .read() and .write()
1648 * can run simultaneously.
1650 * stream_open never fails and is marked to return int so that it could be
1651 * directly used as file_operations.open .
1653 int stream_open(struct inode
*inode
, struct file
*filp
)
1655 filp
->f_mode
&= ~(FMODE_LSEEK
| FMODE_PREAD
| FMODE_PWRITE
| FMODE_ATOMIC_POS
);
1656 filp
->f_mode
|= FMODE_STREAM
;
1660 EXPORT_SYMBOL(stream_open
);