1 files changed, 299 insertions, 0 deletions
diff --git a/fs/utimes.c b/fs/utimes.c
new file mode 100644
index 000000000..39f356017
--- /dev/null
+++ b/fs/utimes.c
@@ -0,0 +1,299 @@
+// 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;
+}
+
+int vfs_utimes(const struct path *path, struct timespec64 *times)
+{
+	int error;
+	struct iattr newattrs;
+	struct inode *inode = path->dentry->d_inode;
+	struct inode *delegated_inode = NULL;
+
+	if (times) {
+		if (!nsec_valid(times[0].tv_nsec) ||
+		    !nsec_valid(times[1].tv_nsec))
+			return -EINVAL;
+		if (times[0].tv_nsec == UTIME_NOW &&
+		    times[1].tv_nsec == UTIME_NOW)
+			times = NULL;
+	}
+
+	error = mnt_want_write(path->mnt);
+	if (error)
+		goto out;
+
+	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(mnt_user_ns(path->mnt), 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;
+}
+
+static int do_utimes_path(int dfd, const char __user *filename,
+		struct timespec64 *times, int flags)
+{
+	struct path path;
+	int lookup_flags = 0, error;
+
+	if (flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH))
+		return -EINVAL;
+
+	if (!(flags & AT_SYMLINK_NOFOLLOW))
+		lookup_flags |= LOOKUP_FOLLOW;
+	if (flags & AT_EMPTY_PATH)
+		lookup_flags |= LOOKUP_EMPTY;
+
+retry:
+	error = user_path_at(dfd, filename, lookup_flags, &path);
+	if (error)
+		return error;
+
+	error = vfs_utimes(&path, times);
+	path_put(&path);
+	if (retry_estale(error, lookup_flags)) {
+		lookup_flags |= LOOKUP_REVAL;
+		goto retry;
+	}
+
+	return error;
+}
+
+static int do_utimes_fd(int fd, struct timespec64 *times, int flags)
+{
+	struct fd f;
+	int error;
+
+	if (flags)
+		return -EINVAL;
+
+	f = fdget(fd);
+	if (!f.file)
+		return -EBADF;
+	error = vfs_utimes(&f.file->f_path, times);
+	fdput(f);
+	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)
+{
+	if (filename == NULL && dfd != AT_FDCWD)
+		return do_utimes_fd(dfd, times, flags);
+	return do_utimes_path(dfd, filename, times, flags);
+}
+
+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(&times, 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, &times->actime) ||
+		    get_user(tv[1].tv_sec, &times->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