Line data Source code
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 :
12 : static bool nsec_valid(long nsec)
13 : {
14 0 : if (nsec == UTIME_OMIT || nsec == UTIME_NOW)
15 : return true;
16 :
17 0 : return nsec >= 0 && nsec <= 999999999;
18 : }
19 :
20 0 : int vfs_utimes(const struct path *path, struct timespec64 *times)
21 : {
22 : int error;
23 : struct iattr newattrs;
24 0 : struct inode *inode = path->dentry->d_inode;
25 0 : struct inode *delegated_inode = NULL;
26 :
27 0 : if (times) {
28 0 : if (!nsec_valid(times[0].tv_nsec) ||
29 0 : !nsec_valid(times[1].tv_nsec))
30 : return -EINVAL;
31 0 : if (times[0].tv_nsec == UTIME_NOW &&
32 : times[1].tv_nsec == UTIME_NOW)
33 0 : times = NULL;
34 : }
35 :
36 0 : error = mnt_want_write(path->mnt);
37 0 : if (error)
38 : goto out;
39 :
40 0 : newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
41 0 : if (times) {
42 0 : if (times[0].tv_nsec == UTIME_OMIT)
43 0 : newattrs.ia_valid &= ~ATTR_ATIME;
44 0 : else if (times[0].tv_nsec != UTIME_NOW) {
45 0 : newattrs.ia_atime = times[0];
46 0 : newattrs.ia_valid |= ATTR_ATIME_SET;
47 : }
48 :
49 0 : if (times[1].tv_nsec == UTIME_OMIT)
50 0 : newattrs.ia_valid &= ~ATTR_MTIME;
51 0 : else if (times[1].tv_nsec != UTIME_NOW) {
52 0 : newattrs.ia_mtime = times[1];
53 0 : 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 0 : newattrs.ia_valid |= ATTR_TIMES_SET;
61 : } else {
62 0 : newattrs.ia_valid |= ATTR_TOUCH;
63 : }
64 : retry_deleg:
65 0 : inode_lock(inode);
66 0 : error = notify_change(mnt_idmap(path->mnt), path->dentry, &newattrs,
67 : &delegated_inode);
68 0 : inode_unlock(inode);
69 0 : if (delegated_inode) {
70 0 : error = break_deleg_wait(&delegated_inode);
71 0 : if (!error)
72 : goto retry_deleg;
73 : }
74 :
75 0 : mnt_drop_write(path->mnt);
76 : out:
77 : return error;
78 : }
79 :
80 0 : static int do_utimes_path(int dfd, const char __user *filename,
81 : struct timespec64 *times, int flags)
82 : {
83 : struct path path;
84 0 : int lookup_flags = 0, error;
85 :
86 0 : if (flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH))
87 : return -EINVAL;
88 :
89 0 : if (!(flags & AT_SYMLINK_NOFOLLOW))
90 0 : lookup_flags |= LOOKUP_FOLLOW;
91 0 : if (flags & AT_EMPTY_PATH)
92 0 : lookup_flags |= LOOKUP_EMPTY;
93 :
94 : retry:
95 0 : error = user_path_at(dfd, filename, lookup_flags, &path);
96 0 : if (error)
97 : return error;
98 :
99 0 : error = vfs_utimes(&path, times);
100 0 : path_put(&path);
101 0 : if (retry_estale(error, lookup_flags)) {
102 0 : lookup_flags |= LOOKUP_REVAL;
103 0 : goto retry;
104 : }
105 :
106 : return error;
107 : }
108 :
109 0 : static int do_utimes_fd(int fd, struct timespec64 *times, int flags)
110 : {
111 : struct fd f;
112 : int error;
113 :
114 0 : if (flags)
115 : return -EINVAL;
116 :
117 0 : f = fdget(fd);
118 0 : if (!f.file)
119 : return -EBADF;
120 0 : error = vfs_utimes(&f.file->f_path, times);
121 0 : 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 : */
140 0 : long do_utimes(int dfd, const char __user *filename, struct timespec64 *times,
141 : int flags)
142 : {
143 0 : if (filename == NULL && dfd != AT_FDCWD)
144 0 : return do_utimes_fd(dfd, times, flags);
145 0 : return do_utimes_path(dfd, filename, times, flags);
146 : }
147 :
148 0 : SYSCALL_DEFINE4(utimensat, int, dfd, const char __user *, filename,
149 : struct __kernel_timespec __user *, utimes, int, flags)
150 : {
151 : struct timespec64 tstimes[2];
152 :
153 0 : if (utimes) {
154 0 : if ((get_timespec64(&tstimes[0], &utimes[0]) ||
155 0 : get_timespec64(&tstimes[1], &utimes[1])))
156 : return -EFAULT;
157 :
158 : /* Nothing to do, we must not even check the path. */
159 0 : if (tstimes[0].tv_nsec == UTIME_OMIT &&
160 0 : tstimes[1].tv_nsec == UTIME_OMIT)
161 : return 0;
162 : }
163 :
164 0 : 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 : */
174 0 : static 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 0 : if (utimes) {
181 0 : if (copy_from_user(×, 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 0 : if (times[0].tv_usec >= 1000000 || times[0].tv_usec < 0 ||
190 0 : times[1].tv_usec >= 1000000 || times[1].tv_usec < 0)
191 : return -EINVAL;
192 :
193 0 : tstimes[0].tv_sec = times[0].tv_sec;
194 0 : tstimes[0].tv_nsec = 1000 * times[0].tv_usec;
195 0 : tstimes[1].tv_sec = times[1].tv_sec;
196 0 : tstimes[1].tv_nsec = 1000 * times[1].tv_usec;
197 : }
198 :
199 0 : return do_utimes(dfd, filename, utimes ? tstimes : NULL, 0);
200 : }
201 :
202 :
203 0 : SYSCALL_DEFINE3(futimesat, int, dfd, const char __user *, filename,
204 : struct __kernel_old_timeval __user *, utimes)
205 : {
206 0 : return do_futimesat(dfd, filename, utimes);
207 : }
208 :
209 0 : SYSCALL_DEFINE2(utimes, char __user *, filename,
210 : struct __kernel_old_timeval __user *, utimes)
211 : {
212 0 : return do_futimesat(AT_FDCWD, filename, utimes);
213 : }
214 :
215 0 : SYSCALL_DEFINE2(utime, char __user *, filename, struct utimbuf __user *, times)
216 : {
217 : struct timespec64 tv[2];
218 :
219 0 : if (times) {
220 0 : if (get_user(tv[0].tv_sec, ×->actime) ||
221 0 : get_user(tv[1].tv_sec, ×->modtime))
222 : return -EFAULT;
223 0 : tv[0].tv_nsec = 0;
224 0 : tv[1].tv_nsec = 0;
225 : }
226 0 : 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
236 : SYSCALL_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 :
252 : SYSCALL_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
268 : static 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 :
288 : SYSCALL_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 :
295 : SYSCALL_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
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