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 delegated_inode delegated_inode = { }; 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 (is_delegated(&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 EXPORT_SYMBOL_GPL(vfs_utimes); 80 81 static int do_utimes_path(int dfd, const char __user *filename, 82 struct timespec64 *times, int flags) 83 { 84 struct path path; 85 int lookup_flags = 0, error; 86 87 if (flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) 88 return -EINVAL; 89 90 if (!(flags & AT_SYMLINK_NOFOLLOW)) 91 lookup_flags |= LOOKUP_FOLLOW; 92 if (flags & AT_EMPTY_PATH) 93 lookup_flags |= LOOKUP_EMPTY; 94 95 retry: 96 error = user_path_at(dfd, filename, lookup_flags, &path); 97 if (error) 98 return error; 99 100 error = vfs_utimes(&path, times); 101 path_put(&path); 102 if (retry_estale(error, lookup_flags)) { 103 lookup_flags |= LOOKUP_REVAL; 104 goto retry; 105 } 106 107 return error; 108 } 109 110 static int do_utimes_fd(int fd, struct timespec64 *times, int flags) 111 { 112 if (flags) 113 return -EINVAL; 114 115 CLASS(fd, f)(fd); 116 if (fd_empty(f)) 117 return -EBADF; 118 return vfs_utimes(&fd_file(f)->f_path, times); 119 } 120 121 /* 122 * do_utimes - change times on filename or file descriptor 123 * @dfd: open file descriptor, -1 or AT_FDCWD 124 * @filename: path name or NULL 125 * @times: new times or NULL 126 * @flags: zero or more flags (only AT_SYMLINK_NOFOLLOW for the moment) 127 * 128 * If filename is NULL and dfd refers to an open file, then operate on 129 * the file. Otherwise look up filename, possibly using dfd as a 130 * starting point. 131 * 132 * If times==NULL, set access and modification to current time, 133 * must be owner or have write permission. 134 * Else, update from *times, must be owner or super user. 135 */ 136 long do_utimes(int dfd, const char __user *filename, struct timespec64 *times, 137 int flags) 138 { 139 if (filename == NULL && dfd != AT_FDCWD) 140 return do_utimes_fd(dfd, times, flags); 141 return do_utimes_path(dfd, filename, times, flags); 142 } 143 144 SYSCALL_DEFINE4(utimensat, int, dfd, const char __user *, filename, 145 struct __kernel_timespec __user *, utimes, int, flags) 146 { 147 struct timespec64 tstimes[2]; 148 149 if (utimes) { 150 if ((get_timespec64(&tstimes[0], &utimes[0]) || 151 get_timespec64(&tstimes[1], &utimes[1]))) 152 return -EFAULT; 153 154 /* Nothing to do, we must not even check the path. */ 155 if (tstimes[0].tv_nsec == UTIME_OMIT && 156 tstimes[1].tv_nsec == UTIME_OMIT) 157 return 0; 158 } 159 160 return do_utimes(dfd, filename, utimes ? tstimes : NULL, flags); 161 } 162 163 #ifdef __ARCH_WANT_SYS_UTIME 164 /* 165 * futimesat(), utimes() and utime() are older versions of utimensat() 166 * that are provided for compatibility with traditional C libraries. 167 * On modern architectures, we always use libc wrappers around 168 * utimensat() instead. 169 */ 170 static long do_futimesat(int dfd, const char __user *filename, 171 struct __kernel_old_timeval __user *utimes) 172 { 173 struct __kernel_old_timeval times[2]; 174 struct timespec64 tstimes[2]; 175 176 if (utimes) { 177 if (copy_from_user(×, utimes, sizeof(times))) 178 return -EFAULT; 179 180 /* This test is needed to catch all invalid values. If we 181 would test only in do_utimes we would miss those invalid 182 values truncated by the multiplication with 1000. Note 183 that we also catch UTIME_{NOW,OMIT} here which are only 184 valid for utimensat. */ 185 if (times[0].tv_usec >= 1000000 || times[0].tv_usec < 0 || 186 times[1].tv_usec >= 1000000 || times[1].tv_usec < 0) 187 return -EINVAL; 188 189 tstimes[0].tv_sec = times[0].tv_sec; 190 tstimes[0].tv_nsec = 1000 * times[0].tv_usec; 191 tstimes[1].tv_sec = times[1].tv_sec; 192 tstimes[1].tv_nsec = 1000 * times[1].tv_usec; 193 } 194 195 return do_utimes(dfd, filename, utimes ? tstimes : NULL, 0); 196 } 197 198 199 SYSCALL_DEFINE3(futimesat, int, dfd, const char __user *, filename, 200 struct __kernel_old_timeval __user *, utimes) 201 { 202 return do_futimesat(dfd, filename, utimes); 203 } 204 205 SYSCALL_DEFINE2(utimes, char __user *, filename, 206 struct __kernel_old_timeval __user *, utimes) 207 { 208 return do_futimesat(AT_FDCWD, filename, utimes); 209 } 210 211 SYSCALL_DEFINE2(utime, char __user *, filename, struct utimbuf __user *, times) 212 { 213 struct timespec64 tv[2]; 214 215 if (times) { 216 if (get_user(tv[0].tv_sec, ×->actime) || 217 get_user(tv[1].tv_sec, ×->modtime)) 218 return -EFAULT; 219 tv[0].tv_nsec = 0; 220 tv[1].tv_nsec = 0; 221 } 222 return do_utimes(AT_FDCWD, filename, times ? tv : NULL, 0); 223 } 224 #endif 225 226 #ifdef CONFIG_COMPAT_32BIT_TIME 227 /* 228 * Not all architectures have sys_utime, so implement this in terms 229 * of sys_utimes. 230 */ 231 #ifdef __ARCH_WANT_SYS_UTIME32 232 SYSCALL_DEFINE2(utime32, const char __user *, filename, 233 struct old_utimbuf32 __user *, t) 234 { 235 struct timespec64 tv[2]; 236 237 if (t) { 238 if (get_user(tv[0].tv_sec, &t->actime) || 239 get_user(tv[1].tv_sec, &t->modtime)) 240 return -EFAULT; 241 tv[0].tv_nsec = 0; 242 tv[1].tv_nsec = 0; 243 } 244 return do_utimes(AT_FDCWD, filename, t ? tv : NULL, 0); 245 } 246 #endif 247 248 SYSCALL_DEFINE4(utimensat_time32, unsigned int, dfd, const char __user *, filename, struct old_timespec32 __user *, t, int, flags) 249 { 250 struct timespec64 tv[2]; 251 252 if (t) { 253 if (get_old_timespec32(&tv[0], &t[0]) || 254 get_old_timespec32(&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 } 262 263 #ifdef __ARCH_WANT_SYS_UTIME32 264 static long do_compat_futimesat(unsigned int dfd, const char __user *filename, 265 struct old_timeval32 __user *t) 266 { 267 struct timespec64 tv[2]; 268 269 if (t) { 270 if (get_user(tv[0].tv_sec, &t[0].tv_sec) || 271 get_user(tv[0].tv_nsec, &t[0].tv_usec) || 272 get_user(tv[1].tv_sec, &t[1].tv_sec) || 273 get_user(tv[1].tv_nsec, &t[1].tv_usec)) 274 return -EFAULT; 275 if (tv[0].tv_nsec >= 1000000 || tv[0].tv_nsec < 0 || 276 tv[1].tv_nsec >= 1000000 || tv[1].tv_nsec < 0) 277 return -EINVAL; 278 tv[0].tv_nsec *= 1000; 279 tv[1].tv_nsec *= 1000; 280 } 281 return do_utimes(dfd, filename, t ? tv : NULL, 0); 282 } 283 284 SYSCALL_DEFINE3(futimesat_time32, unsigned int, dfd, 285 const char __user *, filename, 286 struct old_timeval32 __user *, t) 287 { 288 return do_compat_futimesat(dfd, filename, t); 289 } 290 291 SYSCALL_DEFINE2(utimes_time32, const char __user *, filename, struct old_timeval32 __user *, t) 292 { 293 return do_compat_futimesat(AT_FDCWD, filename, t); 294 } 295 #endif 296 #endif 297