DragonFlyBSD

Changing the access and modification times of a file to anything other than
the current time can only be done by the owner of the file or the super-user as per
POSIX.

At present it is possible to do so just by having write access to the file.

A simple example follows:

touch foo; chown root:user foo; chmod 664 foo; touch -t 200805101024 foo

The last operation should normally fail.

I noticed this as part of my work on adding support for utimensat(). I believe
the fix can be consolidated outside of the implementation of the utimes/utimensat
system calls.