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