Fix permission checking for the new utimensat() system call

Commit 1c710c896e added the utimensat()
system call, but didn't handle the case of checking for the writability
of the target right, when the target was a file descriptor, not a
filename.

We cannot use vfs_permission(MAY_WRITE) for that case, and need to
simply check whether the file descriptor is writable.  The oops from
using the wrong function was noticed and narrowed down by Markus
Trippelsdorf.

Cc: Ulrich Drepper <drepper@redhat.com>
Cc: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Al Viro <viro@ftp.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Linus Torvalds 2007-07-08 12:02:55 -07:00
parent 4e99325b46
commit 1e5de2837c

View file

@ -106,9 +106,16 @@ long do_utimes(int dfd, char __user *filename, struct timespec *times, int flags
if (IS_IMMUTABLE(inode))
goto dput_and_out;
if (current->fsuid != inode->i_uid &&
(error = vfs_permission(&nd, MAY_WRITE)) != 0)
goto dput_and_out;
if (current->fsuid != inode->i_uid) {
if (f) {
if (!(f->f_mode & FMODE_WRITE))
goto dput_and_out;
} else {
error = vfs_permission(&nd, MAY_WRITE);
if (error)
goto dput_and_out;
}
}
}
mutex_lock(&inode->i_mutex);
error = notify_change(dentry, &newattrs);