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