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