// SPDX-License-Identifier: GPL-2.0 #include <linux/file.h> #include <linux/mount.h> #include <linux/namei.h> #include <linux/utime.h> #include <linux/syscalls.h> #include <linux/uaccess.h> #include <linux/compat.h> #include <asm/unistd.h> static bool nsec_valid(long nsec) { if (nsec == UTIME_OMIT || nsec == UTIME_NOW) return true; return nsec >= 0 && nsec <= 999999999; } static int utimes_common(const struct path *path, struct timespec64 *times) { int error; struct iattr newattrs; struct inode *inode = path->dentry->d_inode; struct inode *delegated_inode = NULL; error = mnt_want_write(path->mnt); if (error) goto out; if (times && times[0].tv_nsec == UTIME_NOW && times[1].tv_nsec == UTIME_NOW) times = NULL; newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME; if (times) { if (times[0].tv_nsec == UTIME_OMIT) newattrs.ia_valid &= ~ATTR_ATIME; else if (times[0].tv_nsec != UTIME_NOW) { newattrs.ia_atime = times[0]; newattrs.ia_valid |= ATTR_ATIME_SET; } if (times[1].tv_nsec == UTIME_OMIT) newattrs.ia_valid &= ~ATTR_MTIME; else if (times[1].tv_nsec != UTIME_NOW) { newattrs.ia_mtime = times[1]; newattrs.ia_valid |= ATTR_MTIME_SET; } /* * Tell setattr_prepare(), that this is an explicit time * update, even if neither ATTR_ATIME_SET nor ATTR_MTIME_SET * were used. */ newattrs.ia_valid |= ATTR_TIMES_SET; } else { newattrs.ia_valid |= ATTR_TOUCH; } retry_deleg: inode_lock(inode); error = notify_change(path->dentry, &newattrs, &delegated_inode); inode_unlock(inode); if (delegated_inode) { error = break_deleg_wait(&delegated_inode); if (!error) goto retry_deleg; } mnt_drop_write(path->mnt); out: return error; } /* * do_utimes - change times on filename or file descriptor * @dfd: open file descriptor, -1 or AT_FDCWD * @filename: path name or NULL * @times: new times or NULL * @flags: zero or more flags (only AT_SYMLINK_NOFOLLOW for the moment) * * If filename is NULL and dfd refers to an open file, then operate on * the file. Otherwise look up filename, possibly using dfd as a * starting point. * * If times==NULL, set access and modification to current time, * must be owner or have write permission. * Else, update from *times, must be owner or super user. */ long do_utimes(int dfd, const char __user *filename, struct timespec64 *times, int flags) { int error = -EINVAL; if (times && (!nsec_valid(times[0].tv_nsec) || !nsec_valid(times[1].tv_nsec))) { goto out; } if (flags & ~AT_SYMLINK_NOFOLLOW) goto out; if (filename == NULL && dfd != AT_FDCWD) { struct fd f; if (flags & AT_SYMLINK_NOFOLLOW) goto out; f = fdget(dfd); error = -EBADF; if (!f.file) goto out; error = utimes_common(&f.file->f_path, times); fdput(f); } else { struct path path; int lookup_flags = 0; if (!(flags & AT_SYMLINK_NOFOLLOW)) lookup_flags |= LOOKUP_FOLLOW; retry: error = user_path_at(dfd, filename, lookup_flags, &path); if (error) goto out; error = utimes_common(&path, times); path_put(&path); if (retry_estale(error, lookup_flags)) { lookup_flags |= LOOKUP_REVAL; goto retry; } } out: return error; } SYSCALL_DEFINE4(utimensat, int, dfd, const char __user *, filename, struct __kernel_timespec __user *, utimes, int, flags) { struct timespec64 tstimes[2]; if (utimes) { if ((get_timespec64(&tstimes[0], &utimes[0]) || get_timespec64(&tstimes[1], &utimes[1]))) return -EFAULT; /* Nothing to do, we must not even check the path. */ if (tstimes[0].tv_nsec == UTIME_OMIT && tstimes[1].tv_nsec == UTIME_OMIT) return 0; } return do_utimes(dfd, filename, utimes ? tstimes : NULL, flags); } #ifdef __ARCH_WANT_SYS_UTIME /* * futimesat(), utimes() and utime() are older versions of utimensat() * that are provided for compatibility with traditional C libraries. * On modern architectures, we always use libc wrappers around * utimensat() instead. */ static long do_futimesat(int dfd, const char __user *filename, struct __kernel_old_timeval __user *utimes) { struct __kernel_old_timeval times[2]; struct timespec64 tstimes[2]; if (utimes) { if (copy_from_user(×, utimes, sizeof(times))) return -EFAULT; /* This test is needed to catch all invalid values. If we would test only in do_utimes we would miss those invalid values truncated by the multiplication with 1000. Note that we also catch UTIME_{NOW,OMIT} here which are only valid for utimensat. */ if (times[0].tv_usec >= 1000000 || times[0].tv_usec < 0 || times[1].tv_usec >= 1000000 || times[1].tv_usec < 0) return -EINVAL; tstimes[0].tv_sec = times[0].tv_sec; tstimes[0].tv_nsec = 1000 * times[0].tv_usec; tstimes[1].tv_sec = times[1].tv_sec; tstimes[1].tv_nsec = 1000 * times[1].tv_usec; } return do_utimes(dfd, filename, utimes ? tstimes : NULL, 0); } SYSCALL_DEFINE3(futimesat, int, dfd, const char __user *, filename, struct __kernel_old_timeval __user *, utimes) { return do_futimesat(dfd, filename, utimes); } SYSCALL_DEFINE2(utimes, char __user *, filename, struct __kernel_old_timeval __user *, utimes) { return do_futimesat(AT_FDCWD, filename, utimes); } SYSCALL_DEFINE2(utime, char __user *, filename, struct utimbuf __user *, times) { struct timespec64 tv[2]; if (times) { if (get_user(tv[0].tv_sec, ×->actime) || get_user(tv[1].tv_sec, ×->modtime)) return -EFAULT; tv[0].tv_nsec = 0; tv[1].tv_nsec = 0; } return do_utimes(AT_FDCWD, filename, times ? tv : NULL, 0); } #endif #ifdef CONFIG_COMPAT_32BIT_TIME /* * Not all architectures have sys_utime, so implement this in terms * of sys_utimes. */ #ifdef __ARCH_WANT_SYS_UTIME32 SYSCALL_DEFINE2(utime32, const char __user *, filename, struct old_utimbuf32 __user *, t) { struct timespec64 tv[2]; if (t) { if (get_user(tv[0].tv_sec, &t->actime) || get_user(tv[1].tv_sec, &t->modtime)) return -EFAULT; tv[0].tv_nsec = 0; tv[1].tv_nsec = 0; } return do_utimes(AT_FDCWD, filename, t ? tv : NULL, 0); } #endif SYSCALL_DEFINE4(utimensat_time32, unsigned int, dfd, const char __user *, filename, struct old_timespec32 __user *, t, int, flags) { struct timespec64 tv[2]; if (t) { if (get_old_timespec32(&tv[0], &t[0]) || get_old_timespec32(&tv[1], &t[1])) return -EFAULT; if (tv[0].tv_nsec == UTIME_OMIT && tv[1].tv_nsec == UTIME_OMIT) return 0; } return do_utimes(dfd, filename, t ? tv : NULL, flags); } #ifdef __ARCH_WANT_SYS_UTIME32 static long do_compat_futimesat(unsigned int dfd, const char __user *filename, struct old_timeval32 __user *t) { struct timespec64 tv[2]; if (t) { if (get_user(tv[0].tv_sec, &t[0].tv_sec) || get_user(tv[0].tv_nsec, &t[0].tv_usec) || get_user(tv[1].tv_sec, &t[1].tv_sec) || get_user(tv[1].tv_nsec, &t[1].tv_usec)) return -EFAULT; if (tv[0].tv_nsec >= 1000000 || tv[0].tv_nsec < 0 || tv[1].tv_nsec >= 1000000 || tv[1].tv_nsec < 0) return -EINVAL; tv[0].tv_nsec *= 1000; tv[1].tv_nsec *= 1000; } return do_utimes(dfd, filename, t ? tv : NULL, 0); } SYSCALL_DEFINE3(futimesat_time32, unsigned int, dfd, const char __user *, filename, struct old_timeval32 __user *, t) { return do_compat_futimesat(dfd, filename, t); } SYSCALL_DEFINE2(utimes_time32, const char __user *, filename, struct old_timeval32 __user *, t) { return do_compat_futimesat(AT_FDCWD, filename, t); } #endif #endif