Iron Bars SHell

A buffer overflow and 2 string bugs were fixed.

A format string vulnerability in a syslog call was
fixed. This vulnerability could have allowed users
to access files outside the home directory.

Two segfaults, caused by non-US characters and empty files,
were fixed. Ctrl-Z is now ignored, and sample XTNL config files
were added for help.

Major bugfixes in the Makefile and the code. The messages about removing rights on illegal files are removed.

In this release, the admin has the opportunity to create a
separate cmds file for each user. This way the sysadmin has
complete control over sensitive applications, which should
only be allowed to a selected few. The admin also has the
opportunity to create a separate xtns file for each user. The
extensions policy has been changed. Now both globals.xtns
and the user extension files will list the extensions that are
_allowed_ ! While the code for the search of illegal/
dangerous material stored in user space is back, it will not
erase any files any more. Instead, it will remove all rights
from that file, so it can not be executed, or read. This is
another "defense line" to stop the user to execute programs,
stored in user space. The access to all Linux binaries and
source code files stored in user space is now be blocked.
Absolute path for restricted users cannot be longer then 255
characters. All files that are longer (with full path), will be
renamed. There are also minor bugfixes.