Paranoid - Paranoia support for safer programs

       Arthur Corliss (corliss@digitalmages.com)

       While this module itself doesn't have any external dependencies various child modules do.  Please check
       their documentation for any particulars should you use them.

       This collection of modules started out as modules which perform things (debatably) in a safer and taint-
       safe manner.  Since then it's also grown to include functionality that fit into the same framework and
       conventions of the original modules, including keeping the debug hooks for command-line debugging.

       All the modules below are intended to be used directly in your programs if you need the functionality
       they provide.

       This module does provide one function meant to secure your environment enough to satisfy taint-enabled
       programs, and as a container which holds the last reported error from any code in the Paranoid framework.

       This module exports the following symbols by default:

           psecureEnv

       The following specialized import lists also exist:

           List        Members
           --------------------------------------------------------
           all         @defaults PTRUE_ZERO

       This  software  is  free  software.   Similar to Perl, you can redistribute it and/or modify it under the
       terms of either:

         a)     the GNU General Public License
                <https://www.gnu.org/licenses/gpl-1.0.html> as published by the
                Free Software Foundation <http://www.fsf.org/>; either version 1
                <https://www.gnu.org/licenses/gpl-1.0.html>, or any later version
                <https://www.gnu.org/licenses/license-list.html#GNUGPL>, or
         b)     the Artistic License 2.0
                <https://opensource.org/licenses/Artistic-2.0>,

       subject to the following additional term:  No trademark rights to "Paranoid" have been  or  are  conveyed
       under  any  of  the  above  licenses.  However, "Paranoid" may be used fairly to describe this unmodified
       software, in good faith, but not as a trademark.

       (c)  2005  -  2020,  Arthur  Corliss  (corliss@digitalmages.com)  (tm)  2008  -   2020,   Paranoid   Inc.
       (www.paranoid.com)

perl v5.38.2                                       2024-03-07                                      Paranoid(3pm)

       Paranoid - Paranoia support for safer programs

       The following modules are available for use.  You should check their POD for specifics on use:

       o   Paranoid::Args: Command-line argument parsing functions

       o   Paranoid::Data: Misc. data manipulation functions

       o   Paranoid::Data::AVLTree: AVL-Balanced Tree Class

       o   Paranoid::Data::AVLTree::AVLNode: AVL-Balanced Tree Node Class

       o   Paranoid::Debug: Command-line debugging framework and functions

       o   Paranoid::Filesystem: Filesystem operation functions

       o   Paranoid::Glob: Paranoid Glob objects

       o   Paranoid::IO: File I/O wrappers for sysopen, etc.

       o   Paranoid::IO::FileMultiplexer: File Multiplexer Object

       o   Paranoid::IO::FileMultiplexer::Block: Block-level Allocator/Accessor

       o   Paranoid::IO::FileMultiplexer::Block::BATHeader: BAT Header Block

       o   Paranoid::IO::FileMultiplexer::Block::FileHeader: File Header Block

       o   Paranoid::IO::FileMultiplexer::Block::StreamHeader: Stream Header Block

       o   Paranoid::IO::Line: I/O functions for working with line-based files

       o   Paranoid::IO::Lockfile: I/O functions for working with lock files

       o   Paranoid::Input: Input-related functions (file reading, detainting)

       o   Paranoid::Log: Unified logging framework and functions

       o   Paranoid::Log::Buffer: Buffered-based logging mechanism

       o   Paranoid::Log::File: File-based logging mechanism

       o   Paranoid::Module: Run-time module loading functions

       o   Paranoid::Network: Network-related functions

       o   Paranoid::Network::IPv4: General IPv4-related functions

       o   Paranoid::Network::IPv6: General IPv6-related functions

       o   Paranoid::Network::Socket: Wrapper module for Socket & Socket6

       o   Paranoid::Process: Process management functions

psecureEnv
         psecureEnv("/bin:/usr/bin");

       This function deletes some of the dangerous environment variables that can be used to subvert perl when
       being run in setuid applications.  It also sets the path, either to the passed argument (if passed) or a
       default of "/bin:/sbin:/usr/bin:/usr/sbin".

       NOTE: I did explicitly exclude /usr/local directories from the default path for the following reason:
       /usr/local is often used by admins to stash random scripts and programs which may not have undergone any
       serious scrutiny and review for security issues.  Only the base OS directories are presumed as safe, and
       even that may be stretching the truth as it is.  You can override the defaults as desired.

   Paranoid::ERROR
         $errMsg = Paranoid::ERROR;
         Paranoid::ERROR = $errMsg;

       This lvalue function is not exported and must be referenced via the Paranoid namespace.

   PTRUE_ZERO
       This is a constant that evaluates to '0 but true', which allows 0 to be passed for boolean true use-
       cases.

         use Paranoid;

         $errMsg = Paranoid::ERROR;

         psecureEnv("/bin:/usr/bin");

         sub foo {
           # this function can return '0' as a valid return value
           # that should be construed as a boolean true value

           return PTRUE_ZERO;
         }

       Taint-mode programming can be somewhat of an adventure until you know all the places considered dangerous
       under perl's taint mode.  The following functions should generally have their arguments detainted before
       using:

         exec        system      open        glob
         unlink      mkdir       chdir       rmdir
         chown       chmod       umask       utime
         link        symlink     kill        eval
         truncate    ioctl       fcntl       chroot
         setpgrp     setpriority syscall     socket
         socketpair  bind        connect

       $Id: lib/Paranoid.pm, 2.10 2022/03/08 00:01:04 acorliss Exp $