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 if (nsec == UTIME_OMIT || nsec == UTIME_NOW) 15 return true; 16 17 return nsec >= 0 && nsec <= 999999999; 18 } 19 20 int vfs_utimes(const struct path *path, struct timespec64 *times) 21 { 22 int error; 23 struct iattr newattrs; 24 struct inode *inode = path->dentry->d_inode; 25 struct inode *delegated_inode = NULL; 26 27 if (times) { 28 if (!nsec_valid(times[0].tv_nsec) || 29 !nsec_valid(times[1].tv_nsec)) 30 return -EINVAL; 31 if (times[0].tv_nsec == UTIME_NOW && 32 times[1].tv_nsec == UTIME_NOW) 33 times = NULL; 34 } 35 36 error = mnt_want_write(path->mnt); 37 if (error) 38 goto out; 39 40 newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME; 41 if (times) { 42 if (times[0].tv_nsec == UTIME_OMIT) 43 newattrs.ia_valid &= ~ATTR_ATIME; 44 else if (times[0].tv_nsec != UTIME_NOW) { 45 newattrs.ia_atime = times[0]; 46 newattrs.ia_valid |= ATTR_ATIME_SET; 47 } 48 49 if (times[1].tv_nsec == UTIME_OMIT) 50 newattrs.ia_valid &= ~ATTR_MTIME; 51 else if (times[1].tv_nsec != UTIME_NOW) { 52 newattrs.ia_mtime = times[1]; 53 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 newattrs.ia_valid |= ATTR_TIMES_SET; 61 } else { 62 newattrs.ia_valid |= ATTR_TOUCH; 63 } 64 retry_deleg: 65 inode_lock(inode); 66 error = notify_change(mnt_idmap(path->mnt), path->dentry, &newattrs, 67 &delegated_inode); 68 inode_unlock(inode); 69 if (delegated_inode) { 70 error = break_deleg_wait(&delegated_inode); 71 if (!error) 72 goto retry_deleg; 73 } 74 75 mnt_drop_write(path->mnt); 76 out: 77 return error; 78 } 79 80 static int do_utimes_path(int dfd, const char __user *filename, 81 struct timespec64 *times, int flags) 82 { 83 struct path path; 84 int lookup_flags = 0, error; 85 86 if (flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) 87 return -EINVAL; 88 89 if (!(flags & AT_SYMLINK_NOFOLLOW)) 90 lookup_flags |= LOOKUP_FOLLOW; 91 if (flags & AT_EMPTY_PATH) 92 lookup_flags |= LOOKUP_EMPTY; 93 94 retry: 95 error = user_path_at(dfd, filename, lookup_flags, &path); 96 if (error) 97 return error; 98 99 error = vfs_utimes(&path, times); 100 path_put(&path); 101 if (retry_estale(error, lookup_flags)) { 102 lookup_flags |= LOOKUP_REVAL; 103 goto retry; 104 } 105 106 return error; 107 } 108 109 static int do_utimes_fd(int fd, struct timespec64 *times, int flags) 110 { 111 struct fd f; 112 int error; 113 114 if (flags) 115 return -EINVAL; 116 117 f = fdget(fd); 118 if (!f.file) 119 return -EBADF; 120 error = vfs_utimes(&f.file->f_path, times); 121 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 long do_utimes(int dfd, const char __user *filename, struct timespec64 *times, 141 int flags) 142 { 143 if (filename == NULL && dfd != AT_FDCWD) 144 return do_utimes_fd(dfd, times, flags); 145 return do_utimes_path(dfd, filename, times, flags); 146 } 147 148 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 if (utimes) { 154 if ((get_timespec64(&tstimes[0], &utimes[0]) || 155 get_timespec64(&tstimes[1], &utimes[1]))) 156 return -EFAULT; 157 158 /* Nothing to do, we must not even check the path. */ 159 if (tstimes[0].tv_nsec == UTIME_OMIT && 160 tstimes[1].tv_nsec == UTIME_OMIT) 161 return 0; 162 } 163 164 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 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 if (utimes) { 181 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 if (times[0].tv_usec >= 1000000 || times[0].tv_usec < 0 || 190 times[1].tv_usec >= 1000000 || times[1].tv_usec < 0) 191 return -EINVAL; 192 193 tstimes[0].tv_sec = times[0].tv_sec; 194 tstimes[0].tv_nsec = 1000 * times[0].tv_usec; 195 tstimes[1].tv_sec = times[1].tv_sec; 196 tstimes[1].tv_nsec = 1000 * times[1].tv_usec; 197 } 198 199 return do_utimes(dfd, filename, utimes ? tstimes : NULL, 0); 200 } 201 202 203 SYSCALL_DEFINE3(futimesat, int, dfd, const char __user *, filename, 204 struct __kernel_old_timeval __user *, utimes) 205 { 206 return do_futimesat(dfd, filename, utimes); 207 } 208 209 SYSCALL_DEFINE2(utimes, char __user *, filename, 210 struct __kernel_old_timeval __user *, utimes) 211 { 212 return do_futimesat(AT_FDCWD, filename, utimes); 213 } 214 215 SYSCALL_DEFINE2(utime, char __user *, filename, struct utimbuf __user *, times) 216 { 217 struct timespec64 tv[2]; 218 219 if (times) { 220 if (get_user(tv[0].tv_sec, ×->actime) || 221 get_user(tv[1].tv_sec, ×->modtime)) 222 return -EFAULT; 223 tv[0].tv_nsec = 0; 224 tv[1].tv_nsec = 0; 225 } 226 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 301