[mirror_ubuntu-bionic-kernel.git] / fs / utimes.c

// SPDX-License-Identifier: GPL-2.0
#include <linux/file.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/utime.h>
#include <linux/syscalls.h>
#include <linux/uaccess.h>
#include <linux/compat.h>
#include <asm/unistd.h>

#ifdef __ARCH_WANT_SYS_UTIME

/*
 * sys_utime() can be implemented in user-level using sys_utimes().
 * Is this for backwards compatibility?  If so, why not move it
 * into the appropriate arch directory (for those architectures that
 * need it).
 */

/* If times==NULL, set access and modification to current time,
 * must be owner or have write permission.
 * Else, update from *times, must be owner or super user.
 */
SYSCALL_DEFINE2(utime, char __user *, filename, struct utimbuf __user *, times)
{
	struct timespec64 tv[2];

	if (times) {
		if (get_user(tv[0].tv_sec, &times->actime) ||
		    get_user(tv[1].tv_sec, &times->modtime))
			return -EFAULT;
		tv[0].tv_nsec = 0;
		tv[1].tv_nsec = 0;
	}
	return do_utimes(AT_FDCWD, filename, times ? tv : NULL, 0);
}

#endif

static bool nsec_valid(long nsec)
{
	if (nsec == UTIME_OMIT || nsec == UTIME_NOW)
		return true;

	return nsec >= 0 && nsec <= 999999999;
}

static int utimes_common(const struct path *path, struct timespec64 *times)
{
	int error;
	struct iattr newattrs;
	struct inode *inode = path->dentry->d_inode;
	struct inode *delegated_inode = NULL;

	error = mnt_want_write(path->mnt);
	if (error)
		goto out;

	if (times && times[0].tv_nsec == UTIME_NOW &&
		     times[1].tv_nsec == UTIME_NOW)
		times = NULL;

	newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
	if (times) {
		if (times[0].tv_nsec == UTIME_OMIT)
			newattrs.ia_valid &= ~ATTR_ATIME;
		else if (times[0].tv_nsec != UTIME_NOW) {
			newattrs.ia_atime.tv_sec = times[0].tv_sec;
			newattrs.ia_atime.tv_nsec = times[0].tv_nsec;
			newattrs.ia_valid |= ATTR_ATIME_SET;
		}

		if (times[1].tv_nsec == UTIME_OMIT)
			newattrs.ia_valid &= ~ATTR_MTIME;
		else if (times[1].tv_nsec != UTIME_NOW) {
			newattrs.ia_mtime.tv_sec = times[1].tv_sec;
			newattrs.ia_mtime.tv_nsec = times[1].tv_nsec;
			newattrs.ia_valid |= ATTR_MTIME_SET;
		}
		/*
		 * Tell setattr_prepare(), that this is an explicit time
		 * update, even if neither ATTR_ATIME_SET nor ATTR_MTIME_SET
		 * were used.
		 */
		newattrs.ia_valid |= ATTR_TIMES_SET;
	} else {
		newattrs.ia_valid |= ATTR_TOUCH;
	}
retry_deleg:
	inode_lock(inode);
	error = notify_change(path->dentry, &newattrs, &delegated_inode);
	inode_unlock(inode);
	if (delegated_inode) {
		error = break_deleg_wait(&delegated_inode);
		if (!error)
			goto retry_deleg;
	}

	mnt_drop_write(path->mnt);
out:
	return error;
}

/*
 * do_utimes - change times on filename or file descriptor
 * @dfd: open file descriptor, -1 or AT_FDCWD
 * @filename: path name or NULL
 * @times: new times or NULL
 * @flags: zero or more flags (only AT_SYMLINK_NOFOLLOW for the moment)
 *
 * If filename is NULL and dfd refers to an open file, then operate on
 * the file.  Otherwise look up filename, possibly using dfd as a
 * starting point.
 *
 * If times==NULL, set access and modification to current time,
 * must be owner or have write permission.
 * Else, update from *times, must be owner or super user.
 */
long do_utimes(int dfd, const char __user *filename, struct timespec64 *times,
	       int flags)
{
	int error = -EINVAL;

	if (times && (!nsec_valid(times[0].tv_nsec) ||
		      !nsec_valid(times[1].tv_nsec))) {
		goto out;
	}

	if (flags & ~AT_SYMLINK_NOFOLLOW)
		goto out;

	if (filename == NULL && dfd != AT_FDCWD) {
		struct fd f;

		if (flags & AT_SYMLINK_NOFOLLOW)
			goto out;

		f = fdget(dfd);
		error = -EBADF;
		if (!f.file)
			goto out;

		error = utimes_common(&f.file->f_path, times);
		fdput(f);
	} else {
		struct path path;
		int lookup_flags = 0;

		if (!(flags & AT_SYMLINK_NOFOLLOW))
			lookup_flags |= LOOKUP_FOLLOW;
retry:
		error = user_path_at(dfd, filename, lookup_flags, &path);
		if (error)
			goto out;

		error = utimes_common(&path, times);
		path_put(&path);
		if (retry_estale(error, lookup_flags)) {
			lookup_flags |= LOOKUP_REVAL;
			goto retry;
		}
	}

out:
	return error;
}

SYSCALL_DEFINE4(utimensat, int, dfd, const char __user *, filename,
		struct timespec __user *, utimes, int, flags)
{
	struct timespec64 tstimes[2];

	if (utimes) {
		if ((get_timespec64(&tstimes[0], &utimes[0]) ||
			get_timespec64(&tstimes[1], &utimes[1])))
			return -EFAULT;

		/* Nothing to do, we must not even check the path.  */
		if (tstimes[0].tv_nsec == UTIME_OMIT &&
		    tstimes[1].tv_nsec == UTIME_OMIT)
			return 0;
	}

	return do_utimes(dfd, filename, utimes ? tstimes : NULL, flags);
}

SYSCALL_DEFINE3(futimesat, int, dfd, const char __user *, filename,
		struct timeval __user *, utimes)
{
	struct timeval times[2];
	struct timespec64 tstimes[2];

	if (utimes) {
		if (copy_from_user(&times, utimes, sizeof(times)))
			return -EFAULT;

		/* This test is needed to catch all invalid values.  If we
		   would test only in do_utimes we would miss those invalid
		   values truncated by the multiplication with 1000.  Note
		   that we also catch UTIME_{NOW,OMIT} here which are only
		   valid for utimensat.  */
		if (times[0].tv_usec >= 1000000 || times[0].tv_usec < 0 ||
		    times[1].tv_usec >= 1000000 || times[1].tv_usec < 0)
			return -EINVAL;

		tstimes[0].tv_sec = times[0].tv_sec;
		tstimes[0].tv_nsec = 1000 * times[0].tv_usec;
		tstimes[1].tv_sec = times[1].tv_sec;
		tstimes[1].tv_nsec = 1000 * times[1].tv_usec;
	}

	return do_utimes(dfd, filename, utimes ? tstimes : NULL, 0);
}

SYSCALL_DEFINE2(utimes, char __user *, filename,
		struct timeval __user *, utimes)
{
	return sys_futimesat(AT_FDCWD, filename, utimes);
}

#ifdef CONFIG_COMPAT
/*
 * Not all architectures have sys_utime, so implement this in terms
 * of sys_utimes.
 */
COMPAT_SYSCALL_DEFINE2(utime, const char __user *, filename,
		       struct compat_utimbuf __user *, t)
{
	struct timespec64 tv[2];

	if (t) {
		if (get_user(tv[0].tv_sec, &t->actime) ||
		    get_user(tv[1].tv_sec, &t->modtime))
			return -EFAULT;
		tv[0].tv_nsec = 0;
		tv[1].tv_nsec = 0;
	}
	return do_utimes(AT_FDCWD, filename, t ? tv : NULL, 0);
}

COMPAT_SYSCALL_DEFINE4(utimensat, unsigned int, dfd, const char __user *, filename, struct compat_timespec __user *, t, int, flags)
{
	struct timespec64 tv[2];

	if  (t) {
		if (compat_get_timespec64(&tv[0], &t[0]) ||
		    compat_get_timespec64(&tv[1], &t[1]))
			return -EFAULT;

		if (tv[0].tv_nsec == UTIME_OMIT && tv[1].tv_nsec == UTIME_OMIT)
			return 0;
	}
	return do_utimes(dfd, filename, t ? tv : NULL, flags);
}

COMPAT_SYSCALL_DEFINE3(futimesat, unsigned int, dfd, const char __user *, filename, struct compat_timeval __user *, t)
{
	struct timespec64 tv[2];

	if (t) {
		if (get_user(tv[0].tv_sec, &t[0].tv_sec) ||
		    get_user(tv[0].tv_nsec, &t[0].tv_usec) ||
		    get_user(tv[1].tv_sec, &t[1].tv_sec) ||
		    get_user(tv[1].tv_nsec, &t[1].tv_usec))
			return -EFAULT;
		if (tv[0].tv_nsec >= 1000000 || tv[0].tv_nsec < 0 ||
		    tv[1].tv_nsec >= 1000000 || tv[1].tv_nsec < 0)
			return -EINVAL;
		tv[0].tv_nsec *= 1000;
		tv[1].tv_nsec *= 1000;
	}
	return do_utimes(dfd, filename, t ? tv : NULL, 0);
}

COMPAT_SYSCALL_DEFINE2(utimes, const char __user *, filename, struct compat_timeval __user *, t)
{
	return compat_sys_futimesat(AT_FDCWD, filename, t);
}
#endif
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
1c710c89	2	#include <linux/file.h>
74f9fdfa	3	#include <linux/mount.h>
82b0547c AD	4	#include <linux/namei.h>
82b0547c AD	5	#include <linux/utime.h>
12c2ab5e	6	#include <linux/syscalls.h>
7c0f6ba6	7	#include <linux/uaccess.h>
1a060ba3	8	#include <linux/compat.h>
82b0547c AD	9	#include <asm/unistd.h>
	10
	11	#ifdef __ARCH_WANT_SYS_UTIME
	12
	13	/*
	14	* sys_utime() can be implemented in user-level using sys_utimes().
	15	* Is this for backwards compatibility? If so, why not move it
	16	* into the appropriate arch directory (for those architectures that
	17	* need it).
	18	*/
	19
	20	/* If times==NULL, set access and modification to current time,
	21	* must be owner or have write permission.
	22	* Else, update from *times, must be owner or super user.
	23	*/
003d7ab4	24	SYSCALL_DEFINE2(utime, char __user , filename, struct utimbuf __user , times)
82b0547c	25	{
aaed2dd8	26	struct timespec64 tv[2];
82b0547c	27
82b0547c	28	if (times) {
1c710c89 UD	29	if (get_user(tv[0].tv_sec, &times->actime) \|\|
	30	get_user(tv[1].tv_sec, &times->modtime))
	31	return -EFAULT;
	32	tv[0].tv_nsec = 0;
	33	tv[1].tv_nsec = 0;
82b0547c	34	}
1c710c89	35	return do_utimes(AT_FDCWD, filename, times ? tv : NULL, 0);
82b0547c AD	36	}
	37
	38	#endif
	39
043f46f6 MS	40	static bool nsec_valid(long nsec)
043f46f6 MS	41	{
4cca9226	42	if (nsec == UTIME_OMIT \|\| nsec == UTIME_NOW)
043f46f6 MS	43	return true;
	44
	45	return nsec >= 0 && nsec <= 999999999;
	46	}
	47
aaed2dd8	48	static int utimes_common(const struct path path, struct timespec64 times)
82b0547c AD	49	{
82b0547c AD	50	int error;
82b0547c	51	struct iattr newattrs;
e9b76fed	52	struct inode *inode = path->dentry->d_inode;
27ac0ffe	53	struct inode *delegated_inode = NULL;
82b0547c	54
e9b76fed	55	error = mnt_want_write(path->mnt);
74f9fdfa	56	if (error)
e9b76fed	57	goto out;
82b0547c	58
12fd0d30 MK	59	if (times && times[0].tv_nsec == UTIME_NOW &&
	60	times[1].tv_nsec == UTIME_NOW)
	61	times = NULL;
	62
82b0547c AD	63	newattrs.ia_valid = ATTR_CTIME \| ATTR_MTIME \| ATTR_ATIME;
82b0547c AD	64	if (times) {
1c710c89 UD	65	if (times[0].tv_nsec == UTIME_OMIT)
	66	newattrs.ia_valid &= ~ATTR_ATIME;
	67	else if (times[0].tv_nsec != UTIME_NOW) {
	68	newattrs.ia_atime.tv_sec = times[0].tv_sec;
	69	newattrs.ia_atime.tv_nsec = times[0].tv_nsec;
	70	newattrs.ia_valid \|= ATTR_ATIME_SET;
	71	}
	72
	73	if (times[1].tv_nsec == UTIME_OMIT)
	74	newattrs.ia_valid &= ~ATTR_MTIME;
	75	else if (times[1].tv_nsec != UTIME_NOW) {
	76	newattrs.ia_mtime.tv_sec = times[1].tv_sec;
	77	newattrs.ia_mtime.tv_nsec = times[1].tv_nsec;
	78	newattrs.ia_valid \|= ATTR_MTIME_SET;
	79	}
4cca9226	80	/*
31051c85	81	* Tell setattr_prepare(), that this is an explicit time
9767d749 MS	82	* update, even if neither ATTR_ATIME_SET nor ATTR_MTIME_SET
9767d749 MS	83	* were used.
4cca9226	84	*/
9767d749	85	newattrs.ia_valid \|= ATTR_TIMES_SET;
4cca9226	86	} else {
f2b20f6e	87	newattrs.ia_valid \|= ATTR_TOUCH;
82b0547c	88	}
27ac0ffe	89	retry_deleg:
5955102c	90	inode_lock(inode);
27ac0ffe	91	error = notify_change(path->dentry, &newattrs, &delegated_inode);
5955102c	92	inode_unlock(inode);
27ac0ffe BF	93	if (delegated_inode) {
	94	error = break_deleg_wait(&delegated_inode);
	95	if (!error)
	96	goto retry_deleg;
	97	}
e9b76fed	98
e9b76fed MS	99	mnt_drop_write(path->mnt);
	100	out:
	101	return error;
	102	}
	103
	104	/*
	105	* do_utimes - change times on filename or file descriptor
	106	* @dfd: open file descriptor, -1 or AT_FDCWD
	107	* @filename: path name or NULL
	108	* @times: new times or NULL
	109	* @flags: zero or more flags (only AT_SYMLINK_NOFOLLOW for the moment)
	110	*
	111	* If filename is NULL and dfd refers to an open file, then operate on
	112	* the file. Otherwise look up filename, possibly using dfd as a
	113	* starting point.
	114	*
	115	* If times==NULL, set access and modification to current time,
	116	* must be owner or have write permission.
	117	* Else, update from *times, must be owner or super user.
	118	*/
aaed2dd8	119	long do_utimes(int dfd, const char __user filename, struct timespec64 times,
c7887325	120	int flags)
e9b76fed MS	121	{
	122	int error = -EINVAL;
	123
	124	if (times && (!nsec_valid(times[0].tv_nsec) \|\|
	125	!nsec_valid(times[1].tv_nsec))) {
	126	goto out;
	127	}
	128
	129	if (flags & ~AT_SYMLINK_NOFOLLOW)
	130	goto out;
	131
	132	if (filename == NULL && dfd != AT_FDCWD) {
2903ff01	133	struct fd f;
e9b76fed MS	134
	135	if (flags & AT_SYMLINK_NOFOLLOW)
	136	goto out;
	137
2903ff01	138	f = fdget(dfd);
e9b76fed	139	error = -EBADF;
2903ff01	140	if (!f.file)
e9b76fed MS	141	goto out;
e9b76fed MS	142
2903ff01 AV	143	error = utimes_common(&f.file->f_path, times);
2903ff01 AV	144	fdput(f);
e9b76fed	145	} else {
2d8f3038	146	struct path path;
e9b76fed MS	147	int lookup_flags = 0;
	148
	149	if (!(flags & AT_SYMLINK_NOFOLLOW))
	150	lookup_flags \|= LOOKUP_FOLLOW;
a69201d6	151	retry:
2d8f3038	152	error = user_path_at(dfd, filename, lookup_flags, &path);
e9b76fed MS	153	if (error)
	154	goto out;
	155
2d8f3038 AV	156	error = utimes_common(&path, times);
2d8f3038 AV	157	path_put(&path);
a69201d6 JL	158	if (retry_estale(error, lookup_flags)) {
	159	lookup_flags \|= LOOKUP_REVAL;
	160	goto retry;
	161	}
e9b76fed MS	162	}
e9b76fed MS	163
82b0547c AD	164	out:
	165	return error;
	166	}
	167
c7887325	168	SYSCALL_DEFINE4(utimensat, int, dfd, const char __user *, filename,
6559eed8	169	struct timespec __user *, utimes, int, flags)
1c710c89	170	{
aaed2dd8	171	struct timespec64 tstimes[2];
1c710c89 UD	172
1c710c89 UD	173	if (utimes) {
aaed2dd8 DD	174	if ((get_timespec64(&tstimes[0], &utimes[0]) \|\|
aaed2dd8 DD	175	get_timespec64(&tstimes[1], &utimes[1])))
1c710c89	176	return -EFAULT;
1c710c89 UD	177
	178	/* Nothing to do, we must not even check the path. */
	179	if (tstimes[0].tv_nsec == UTIME_OMIT &&
	180	tstimes[1].tv_nsec == UTIME_OMIT)
	181	return 0;
	182	}
	183
	184	return do_utimes(dfd, filename, utimes ? tstimes : NULL, flags);
	185	}
	186
c7887325	187	SYSCALL_DEFINE3(futimesat, int, dfd, const char __user *, filename,
6559eed8	188	struct timeval __user *, utimes)
82b0547c AD	189	{
82b0547c AD	190	struct timeval times[2];
aaed2dd8	191	struct timespec64 tstimes[2];
1c710c89 UD	192
	193	if (utimes) {
	194	if (copy_from_user(&times, utimes, sizeof(times)))
	195	return -EFAULT;
	196
	197	/* This test is needed to catch all invalid values. If we
	198	would test only in do_utimes we would miss those invalid
	199	values truncated by the multiplication with 1000. Note
	200	that we also catch UTIME_{NOW,OMIT} here which are only
	201	valid for utimensat. */
	202	if (times[0].tv_usec >= 1000000 \|\| times[0].tv_usec < 0 \|\|
	203	times[1].tv_usec >= 1000000 \|\| times[1].tv_usec < 0)
	204	return -EINVAL;
	205
	206	tstimes[0].tv_sec = times[0].tv_sec;
	207	tstimes[0].tv_nsec = 1000 * times[0].tv_usec;
	208	tstimes[1].tv_sec = times[1].tv_sec;
	209	tstimes[1].tv_nsec = 1000 * times[1].tv_usec;
	210	}
82b0547c	211
1c710c89	212	return do_utimes(dfd, filename, utimes ? tstimes : NULL, 0);
82b0547c AD	213	}
82b0547c AD	214
003d7ab4 HC	215	SYSCALL_DEFINE2(utimes, char __user *, filename,
003d7ab4 HC	216	struct timeval __user *, utimes)
82b0547c AD	217	{
	218	return sys_futimesat(AT_FDCWD, filename, utimes);
	219	}
1a060ba3 AV	220
	221	#ifdef CONFIG_COMPAT
	222	/*
	223	* Not all architectures have sys_utime, so implement this in terms
	224	* of sys_utimes.
	225	*/
	226	COMPAT_SYSCALL_DEFINE2(utime, const char __user *, filename,
	227	struct compat_utimbuf __user *, t)
	228	{
aaed2dd8	229	struct timespec64 tv[2];
1a060ba3 AV	230
	231	if (t) {
	232	if (get_user(tv[0].tv_sec, &t->actime) \|\|
	233	get_user(tv[1].tv_sec, &t->modtime))
	234	return -EFAULT;
	235	tv[0].tv_nsec = 0;
	236	tv[1].tv_nsec = 0;
	237	}
	238	return do_utimes(AT_FDCWD, filename, t ? tv : NULL, 0);
	239	}
	240
	241	COMPAT_SYSCALL_DEFINE4(utimensat, unsigned int, dfd, const char __user , filename, struct compat_timespec __user , t, int, flags)
	242	{
aaed2dd8	243	struct timespec64 tv[2];
1a060ba3 AV	244
1a060ba3 AV	245	if (t) {
aaed2dd8 DD	246	if (compat_get_timespec64(&tv[0], &t[0]) \|\|
aaed2dd8 DD	247	compat_get_timespec64(&tv[1], &t[1]))
1a060ba3 AV	248	return -EFAULT;
	249
	250	if (tv[0].tv_nsec == UTIME_OMIT && tv[1].tv_nsec == UTIME_OMIT)
	251	return 0;
	252	}
	253	return do_utimes(dfd, filename, t ? tv : NULL, flags);
	254	}
	255
	256	COMPAT_SYSCALL_DEFINE3(futimesat, unsigned int, dfd, const char __user , filename, struct compat_timeval __user , t)
	257	{
aaed2dd8	258	struct timespec64 tv[2];
1a060ba3 AV	259
	260	if (t) {
	261	if (get_user(tv[0].tv_sec, &t[0].tv_sec) \|\|
	262	get_user(tv[0].tv_nsec, &t[0].tv_usec) \|\|
	263	get_user(tv[1].tv_sec, &t[1].tv_sec) \|\|
	264	get_user(tv[1].tv_nsec, &t[1].tv_usec))
	265	return -EFAULT;
	266	if (tv[0].tv_nsec >= 1000000 \|\| tv[0].tv_nsec < 0 \|\|
	267	tv[1].tv_nsec >= 1000000 \|\| tv[1].tv_nsec < 0)
	268	return -EINVAL;
	269	tv[0].tv_nsec *= 1000;
	270	tv[1].tv_nsec *= 1000;
	271	}
	272	return do_utimes(dfd, filename, t ? tv : NULL, 0);
	273	}
	274
	275	COMPAT_SYSCALL_DEFINE2(utimes, const char __user , filename, struct compat_timeval __user , t)
	276	{
	277	return compat_sys_futimesat(AT_FDCWD, filename, t);
	278	}
	279	#endif