1// SPDX-License-Identifier: GPL-2.0
2#include <linux/file.h>
3#include <linux/mount.h>
4#include <linux/namei.h>
5#include <linux/utime.h>
6#include <linux/syscalls.h>
7#include <linux/uaccess.h>
8#include <linux/compat.h>
9#include <asm/unistd.h>
10#include <linux/filelock.h>
11
12static bool nsec_valid(long nsec)
13{
14	if (nsec == UTIME_OMIT || nsec == UTIME_NOW)
15		return true;
16
17	return nsec >= 0 && nsec <= 999999999;
18}
19
20int vfs_utimes(const struct path *path, struct timespec64 *times)
21{
22	int error;
23	struct iattr newattrs;
24	struct inode *inode = path->dentry->d_inode;
25	struct inode *delegated_inode = NULL;
26
27	if (times) {
28		if (!nsec_valid(times[0].tv_nsec) ||
29		    !nsec_valid(times[1].tv_nsec))
30			return -EINVAL;
31		if (times[0].tv_nsec == UTIME_NOW &&
32		    times[1].tv_nsec == UTIME_NOW)
33			times = NULL;
34	}
35
36	error = mnt_want_write(path->mnt);
37	if (error)
38		goto out;
39
40	newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
41	if (times) {
42		if (times[0].tv_nsec == UTIME_OMIT)
43			newattrs.ia_valid &= ~ATTR_ATIME;
44		else if (times[0].tv_nsec != UTIME_NOW) {
45			newattrs.ia_atime = times[0];
46			newattrs.ia_valid |= ATTR_ATIME_SET;
47		}
48
49		if (times[1].tv_nsec == UTIME_OMIT)
50			newattrs.ia_valid &= ~ATTR_MTIME;
51		else if (times[1].tv_nsec != UTIME_NOW) {
52			newattrs.ia_mtime = times[1];
53			newattrs.ia_valid |= ATTR_MTIME_SET;
54		}
55		/*
56		 * Tell setattr_prepare(), that this is an explicit time
57		 * update, even if neither ATTR_ATIME_SET nor ATTR_MTIME_SET
58		 * were used.
59		 */
60		newattrs.ia_valid |= ATTR_TIMES_SET;
61	} else {
62		newattrs.ia_valid |= ATTR_TOUCH;
63	}
64retry_deleg:
65	inode_lock(inode);
66	error = notify_change(mnt_idmap(path->mnt), path->dentry, &newattrs,
67			      &delegated_inode);
68	inode_unlock(inode);
69	if (delegated_inode) {
70		error = break_deleg_wait(&delegated_inode);
71		if (!error)
72			goto retry_deleg;
73	}
74
75	mnt_drop_write(path->mnt);
76out:
77	return error;
78}
79
80static int do_utimes_path(int dfd, const char __user *filename,
81		struct timespec64 *times, int flags)
82{
83	struct path path;
84	int lookup_flags = 0, error;
85
86	if (flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH))
87		return -EINVAL;
88
89	if (!(flags & AT_SYMLINK_NOFOLLOW))
90		lookup_flags |= LOOKUP_FOLLOW;
91	if (flags & AT_EMPTY_PATH)
92		lookup_flags |= LOOKUP_EMPTY;
93
94retry:
95	error = user_path_at(dfd, filename, lookup_flags, &path);
96	if (error)
97		return error;
98
99	error = vfs_utimes(&path, times);
100	path_put(&path);
101	if (retry_estale(error, lookup_flags)) {
102		lookup_flags |= LOOKUP_REVAL;
103		goto retry;
104	}
105
106	return error;
107}
108
109static int do_utimes_fd(int fd, struct timespec64 *times, int flags)
110{
111	struct fd f;
112	int error;
113
114	if (flags)
115		return -EINVAL;
116
117	f = fdget(fd);
118	if (!f.file)
119		return -EBADF;
120	error = vfs_utimes(&f.file->f_path, times);
121	fdput(f);
122	return error;
123}
124
125/*
126 * do_utimes - change times on filename or file descriptor
127 * @dfd: open file descriptor, -1 or AT_FDCWD
128 * @filename: path name or NULL
129 * @times: new times or NULL
130 * @flags: zero or more flags (only AT_SYMLINK_NOFOLLOW for the moment)
131 *
132 * If filename is NULL and dfd refers to an open file, then operate on
133 * the file.  Otherwise look up filename, possibly using dfd as a
134 * starting point.
135 *
136 * If times==NULL, set access and modification to current time,
137 * must be owner or have write permission.
138 * Else, update from *times, must be owner or super user.
139 */
140long do_utimes(int dfd, const char __user *filename, struct timespec64 *times,
141	       int flags)
142{
143	if (filename == NULL && dfd != AT_FDCWD)
144		return do_utimes_fd(dfd, times, flags);
145	return do_utimes_path(dfd, filename, times, flags);
146}
147
148SYSCALL_DEFINE4(utimensat, int, dfd, const char __user *, filename,
149		struct __kernel_timespec __user *, utimes, int, flags)
150{
151	struct timespec64 tstimes[2];
152
153	if (utimes) {
154		if ((get_timespec64(&tstimes[0], &utimes[0]) ||
155			get_timespec64(&tstimes[1], &utimes[1])))
156			return -EFAULT;
157
158		/* Nothing to do, we must not even check the path.  */
159		if (tstimes[0].tv_nsec == UTIME_OMIT &&
160		    tstimes[1].tv_nsec == UTIME_OMIT)
161			return 0;
162	}
163
164	return do_utimes(dfd, filename, utimes ? tstimes : NULL, flags);
165}
166
167#ifdef __ARCH_WANT_SYS_UTIME
168/*
169 * futimesat(), utimes() and utime() are older versions of utimensat()
170 * that are provided for compatibility with traditional C libraries.
171 * On modern architectures, we always use libc wrappers around
172 * utimensat() instead.
173 */
174static long do_futimesat(int dfd, const char __user *filename,
175			 struct __kernel_old_timeval __user *utimes)
176{
177	struct __kernel_old_timeval times[2];
178	struct timespec64 tstimes[2];
179
180	if (utimes) {
181		if (copy_from_user(&times, utimes, sizeof(times)))
182			return -EFAULT;
183
184		/* This test is needed to catch all invalid values.  If we
185		   would test only in do_utimes we would miss those invalid
186		   values truncated by the multiplication with 1000.  Note
187		   that we also catch UTIME_{NOW,OMIT} here which are only
188		   valid for utimensat.  */
189		if (times[0].tv_usec >= 1000000 || times[0].tv_usec < 0 ||
190		    times[1].tv_usec >= 1000000 || times[1].tv_usec < 0)
191			return -EINVAL;
192
193		tstimes[0].tv_sec = times[0].tv_sec;
194		tstimes[0].tv_nsec = 1000 * times[0].tv_usec;
195		tstimes[1].tv_sec = times[1].tv_sec;
196		tstimes[1].tv_nsec = 1000 * times[1].tv_usec;
197	}
198
199	return do_utimes(dfd, filename, utimes ? tstimes : NULL, 0);
200}
201
202
203SYSCALL_DEFINE3(futimesat, int, dfd, const char __user *, filename,
204		struct __kernel_old_timeval __user *, utimes)
205{
206	return do_futimesat(dfd, filename, utimes);
207}
208
209SYSCALL_DEFINE2(utimes, char __user *, filename,
210		struct __kernel_old_timeval __user *, utimes)
211{
212	return do_futimesat(AT_FDCWD, filename, utimes);
213}
214
215SYSCALL_DEFINE2(utime, char __user *, filename, struct utimbuf __user *, times)
216{
217	struct timespec64 tv[2];
218
219	if (times) {
220		if (get_user(tv[0].tv_sec, &times->actime) ||
221		    get_user(tv[1].tv_sec, &times->modtime))
222			return -EFAULT;
223		tv[0].tv_nsec = 0;
224		tv[1].tv_nsec = 0;
225	}
226	return do_utimes(AT_FDCWD, filename, times ? tv : NULL, 0);
227}
228#endif
229
230#ifdef CONFIG_COMPAT_32BIT_TIME
231/*
232 * Not all architectures have sys_utime, so implement this in terms
233 * of sys_utimes.
234 */
235#ifdef __ARCH_WANT_SYS_UTIME32
236SYSCALL_DEFINE2(utime32, const char __user *, filename,
237		struct old_utimbuf32 __user *, t)
238{
239	struct timespec64 tv[2];
240
241	if (t) {
242		if (get_user(tv[0].tv_sec, &t->actime) ||
243		    get_user(tv[1].tv_sec, &t->modtime))
244			return -EFAULT;
245		tv[0].tv_nsec = 0;
246		tv[1].tv_nsec = 0;
247	}
248	return do_utimes(AT_FDCWD, filename, t ? tv : NULL, 0);
249}
250#endif
251
252SYSCALL_DEFINE4(utimensat_time32, unsigned int, dfd, const char __user *, filename, struct old_timespec32 __user *, t, int, flags)
253{
254	struct timespec64 tv[2];
255
256	if  (t) {
257		if (get_old_timespec32(&tv[0], &t[0]) ||
258		    get_old_timespec32(&tv[1], &t[1]))
259			return -EFAULT;
260
261		if (tv[0].tv_nsec == UTIME_OMIT && tv[1].tv_nsec == UTIME_OMIT)
262			return 0;
263	}
264	return do_utimes(dfd, filename, t ? tv : NULL, flags);
265}
266
267#ifdef __ARCH_WANT_SYS_UTIME32
268static long do_compat_futimesat(unsigned int dfd, const char __user *filename,
269				struct old_timeval32 __user *t)
270{
271	struct timespec64 tv[2];
272
273	if (t) {
274		if (get_user(tv[0].tv_sec, &t[0].tv_sec) ||
275		    get_user(tv[0].tv_nsec, &t[0].tv_usec) ||
276		    get_user(tv[1].tv_sec, &t[1].tv_sec) ||
277		    get_user(tv[1].tv_nsec, &t[1].tv_usec))
278			return -EFAULT;
279		if (tv[0].tv_nsec >= 1000000 || tv[0].tv_nsec < 0 ||
280		    tv[1].tv_nsec >= 1000000 || tv[1].tv_nsec < 0)
281			return -EINVAL;
282		tv[0].tv_nsec *= 1000;
283		tv[1].tv_nsec *= 1000;
284	}
285	return do_utimes(dfd, filename, t ? tv : NULL, 0);
286}
287
288SYSCALL_DEFINE3(futimesat_time32, unsigned int, dfd,
289		       const char __user *, filename,
290		       struct old_timeval32 __user *, t)
291{
292	return do_compat_futimesat(dfd, filename, t);
293}
294
295SYSCALL_DEFINE2(utimes_time32, const char __user *, filename, struct old_timeval32 __user *, t)
296{
297	return do_compat_futimesat(AT_FDCWD, filename, t);
298}
299#endif
300#endif
301