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
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 */
SYSCALL_DEFINE2(utime,char __user *,filename,struct utimbuf __user *,times)24 SYSCALL_DEFINE2(utime, char __user *, filename, struct utimbuf __user *, times)
25 {
26 struct timespec64 tv[2];
27
28 if (times) {
29 if (get_user(tv[0].tv_sec, ×->actime) ||
30 get_user(tv[1].tv_sec, ×->modtime))
31 return -EFAULT;
32 tv[0].tv_nsec = 0;
33 tv[1].tv_nsec = 0;
34 }
35 return do_utimes(AT_FDCWD, filename, times ? tv : NULL, 0);
36 }
37
38 #endif
39
nsec_valid(long nsec)40 static bool nsec_valid(long nsec)
41 {
42 if (nsec == UTIME_OMIT || nsec == UTIME_NOW)
43 return true;
44
45 return nsec >= 0 && nsec <= 999999999;
46 }
47
utimes_common(const struct path * path,struct timespec64 * times)48 static int utimes_common(const struct path *path, struct timespec64 *times)
49 {
50 int error;
51 struct iattr newattrs;
52 struct inode *inode = path->dentry->d_inode;
53 struct inode *delegated_inode = NULL;
54
55 error = mnt_want_write(path->mnt);
56 if (error)
57 goto out;
58
59 if (times && times[0].tv_nsec == UTIME_NOW &&
60 times[1].tv_nsec == UTIME_NOW)
61 times = NULL;
62
63 newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
64 if (times) {
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 }
80 /*
81 * Tell setattr_prepare(), that this is an explicit time
82 * update, even if neither ATTR_ATIME_SET nor ATTR_MTIME_SET
83 * were used.
84 */
85 newattrs.ia_valid |= ATTR_TIMES_SET;
86 } else {
87 newattrs.ia_valid |= ATTR_TOUCH;
88 }
89 retry_deleg:
90 inode_lock(inode);
91 error = notify_change(path->dentry, &newattrs, &delegated_inode);
92 inode_unlock(inode);
93 if (delegated_inode) {
94 error = break_deleg_wait(&delegated_inode);
95 if (!error)
96 goto retry_deleg;
97 }
98
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 */
do_utimes(int dfd,const char __user * filename,struct timespec64 * times,int flags)119 long do_utimes(int dfd, const char __user *filename, struct timespec64 *times,
120 int flags)
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) {
133 struct fd f;
134
135 if (flags & AT_SYMLINK_NOFOLLOW)
136 goto out;
137
138 f = fdget(dfd);
139 error = -EBADF;
140 if (!f.file)
141 goto out;
142
143 error = utimes_common(&f.file->f_path, times);
144 fdput(f);
145 } else {
146 struct path path;
147 int lookup_flags = 0;
148
149 if (!(flags & AT_SYMLINK_NOFOLLOW))
150 lookup_flags |= LOOKUP_FOLLOW;
151 retry:
152 error = user_path_at(dfd, filename, lookup_flags, &path);
153 if (error)
154 goto out;
155
156 error = utimes_common(&path, times);
157 path_put(&path);
158 if (retry_estale(error, lookup_flags)) {
159 lookup_flags |= LOOKUP_REVAL;
160 goto retry;
161 }
162 }
163
164 out:
165 return error;
166 }
167
SYSCALL_DEFINE4(utimensat,int,dfd,const char __user *,filename,struct timespec __user *,utimes,int,flags)168 SYSCALL_DEFINE4(utimensat, int, dfd, const char __user *, filename,
169 struct timespec __user *, utimes, int, flags)
170 {
171 struct timespec64 tstimes[2];
172
173 if (utimes) {
174 if ((get_timespec64(&tstimes[0], &utimes[0]) ||
175 get_timespec64(&tstimes[1], &utimes[1])))
176 return -EFAULT;
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
do_futimesat(int dfd,const char __user * filename,struct timeval __user * utimes)187 static long do_futimesat(int dfd, const char __user *filename,
188 struct timeval __user *utimes)
189 {
190 struct timeval times[2];
191 struct timespec64 tstimes[2];
192
193 if (utimes) {
194 if (copy_from_user(×, 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 }
211
212 return do_utimes(dfd, filename, utimes ? tstimes : NULL, 0);
213 }
214
215
SYSCALL_DEFINE3(futimesat,int,dfd,const char __user *,filename,struct timeval __user *,utimes)216 SYSCALL_DEFINE3(futimesat, int, dfd, const char __user *, filename,
217 struct timeval __user *, utimes)
218 {
219 return do_futimesat(dfd, filename, utimes);
220 }
221
SYSCALL_DEFINE2(utimes,char __user *,filename,struct timeval __user *,utimes)222 SYSCALL_DEFINE2(utimes, char __user *, filename,
223 struct timeval __user *, utimes)
224 {
225 return do_futimesat(AT_FDCWD, filename, utimes);
226 }
227
228 #ifdef CONFIG_COMPAT
229 /*
230 * Not all architectures have sys_utime, so implement this in terms
231 * of sys_utimes.
232 */
COMPAT_SYSCALL_DEFINE2(utime,const char __user *,filename,struct compat_utimbuf __user *,t)233 COMPAT_SYSCALL_DEFINE2(utime, const char __user *, filename,
234 struct compat_utimbuf __user *, t)
235 {
236 struct timespec64 tv[2];
237
238 if (t) {
239 if (get_user(tv[0].tv_sec, &t->actime) ||
240 get_user(tv[1].tv_sec, &t->modtime))
241 return -EFAULT;
242 tv[0].tv_nsec = 0;
243 tv[1].tv_nsec = 0;
244 }
245 return do_utimes(AT_FDCWD, filename, t ? tv : NULL, 0);
246 }
247
COMPAT_SYSCALL_DEFINE4(utimensat,unsigned int,dfd,const char __user *,filename,struct compat_timespec __user *,t,int,flags)248 COMPAT_SYSCALL_DEFINE4(utimensat, unsigned int, dfd, const char __user *, filename, struct compat_timespec __user *, t, int, flags)
249 {
250 struct timespec64 tv[2];
251
252 if (t) {
253 if (compat_get_timespec64(&tv[0], &t[0]) ||
254 compat_get_timespec64(&tv[1], &t[1]))
255 return -EFAULT;
256
257 if (tv[0].tv_nsec == UTIME_OMIT && tv[1].tv_nsec == UTIME_OMIT)
258 return 0;
259 }
260 return do_utimes(dfd, filename, t ? tv : NULL, flags);
261 }
262
do_compat_futimesat(unsigned int dfd,const char __user * filename,struct compat_timeval __user * t)263 static long do_compat_futimesat(unsigned int dfd, const char __user *filename,
264 struct compat_timeval __user *t)
265 {
266 struct timespec64 tv[2];
267
268 if (t) {
269 if (get_user(tv[0].tv_sec, &t[0].tv_sec) ||
270 get_user(tv[0].tv_nsec, &t[0].tv_usec) ||
271 get_user(tv[1].tv_sec, &t[1].tv_sec) ||
272 get_user(tv[1].tv_nsec, &t[1].tv_usec))
273 return -EFAULT;
274 if (tv[0].tv_nsec >= 1000000 || tv[0].tv_nsec < 0 ||
275 tv[1].tv_nsec >= 1000000 || tv[1].tv_nsec < 0)
276 return -EINVAL;
277 tv[0].tv_nsec *= 1000;
278 tv[1].tv_nsec *= 1000;
279 }
280 return do_utimes(dfd, filename, t ? tv : NULL, 0);
281 }
282
COMPAT_SYSCALL_DEFINE3(futimesat,unsigned int,dfd,const char __user *,filename,struct compat_timeval __user *,t)283 COMPAT_SYSCALL_DEFINE3(futimesat, unsigned int, dfd,
284 const char __user *, filename,
285 struct compat_timeval __user *, t)
286 {
287 return do_compat_futimesat(dfd, filename, t);
288 }
289
COMPAT_SYSCALL_DEFINE2(utimes,const char __user *,filename,struct compat_timeval __user *,t)290 COMPAT_SYSCALL_DEFINE2(utimes, const char __user *, filename, struct compat_timeval __user *, t)
291 {
292 return do_compat_futimesat(AT_FDCWD, filename, t);
293 }
294 #endif
295
