Bug#839260: ghostscript: various sandbox bypasses

[Florian Weimer <fw@deneb.enyo.de>]

Package: ghostscript
Version: 9.19~dfsg-3
Tags: security
Severity: grave

Tavis Ormandy has reported several sandbox bypasses on the
oss-security mailing list.

  <http://www.openwall.com/lists/oss-security/2016/09/29/3>
    (also see follow-ups)

Filed upstream as:

  <http://bugs.ghostscript.com/show_bug.cgi?id=697169>
  <http://bugs.ghostscript.com/show_bug.cgi?id=697178>

This is a fairly important security issue because it introduces
vulnerabilities into CUPS and programs such as mail clients which use
mailcap entries and run Ghostscript indirectly.