Ghostscript/GhostPDL 9.28 Release Candidate 4

Sorry to do this again, but our internal testing uncovered another edge
case problem with the file access controls - unfortunately, fixing it
required changes to the code that adds paths to the permitted lists, and
the code that validates file access permissions - essentially, the
'guts' of the new functionality. The changes are relatively small, but
are touched whenever the access control code is called.

In this case, there was a very small chance of a security breach
(although, it would rely on gs being called with a specifically
formatted output file name on the command line), hence feeling the need
to make the change.

This doesn't delay the 9.28 release further than when rc3 came out, as
long as this is the last release candidate (please!).


The release candidate 4 archives and Windows installers are in the usual
place:

https://github.com/ArtifexSoftware/ghostpdl-downloads/releases/tag/gs928rc4


Once again, I'm going to reiterate comments from the previous candidates
here, just in case anyone missed it the previous times around:


There are some very important changes in this release:

First: we have ground-up rewritten the file access controls that were
the major benefit of the "SAFER" code.

Second: as we've promised (threatened?) for years, SAFER is now enabled
by default (it can still be disabled with "-dNOSAFER").

Third: those of you still paying attention will probably have worked out
that the implication of the above two points is that some very new code
is being enabled by default!

As a consequence, we want to give users an extended chance to find what
we did wrong.

Note that the previous SAFER behaviour can still be accessed by using
"-dSAFER -dOLDSAFER" - but this will only be true until we're convinced
we've got no reason to keep the old behaviour.



Please give the release candidate a try on your system if you're
interested in helping test the release-in-progress. Your feedback is
always appreciated, but especially so with this release.


All the best (and sorry, again!),

Chris