Mail::SpamCannibal::Session - session management utilities

  use Mail::SpamCannibal::Session qw(
	encode
	decode
	mac
	new_ses
	clean
	validate
	sesswrap
  );

  $encoded = encode($string);
  $string = decode($encoded);
  $mac = mac(@elements);
  $sess_id=new_ses($base64ID,$session_dir,\$error,$ses_val);
  $var = clean($tainted);
  $user=validate($session_dir,$sess_id,$secret,\$error,$expire);
  ($user,$content,$file)=validate($session_dir,$sess_id,$secret,\$error,$expire);
  $rv = sesswrap($command,$stdin);

Mail::SpamCannibal::Session provides utilities to manage web sessions.

* $encoded = encode($string);

This function encodes an ascii string into the URL and Filename safe Base64 character set. Character 62 (0x3E) "+" is replaced with a "-" (minus sign) and character 63 (0x3F) "/" is replaced with a "_" (underscore). Pad characters "=" are removed.

  input:	ascii string
  returns:	modified Base64 encoded string

* $string = decode($encoded);

This function decodes a <URL and Filename safe> Base64 encoded string.

  input:	encoded string
  returns:	text string

* $mac = mac(@elements);

This function makes a URL and Filename safe BASE64 MD5 hash of from the supplies text string(s). Character 62 (0x3E) "+" is replaced with a "-" (minus sign) and character 63 (0x3F) "/" is replaced with a "_" (underscore).

  input:	one or more input elements
  returns:	modified base64 string

* $sess_id = new_ses($base64ID,$session_dir,\$error,$ses_val);

Create a new session and return the identifying string.

  input:	session directory path,
		base64 unique ID, (URL safe)
		secret key for MAC,
		pointer to $error scalar,
		[optional] value for session
		file contents, default -1

Normally the session file is created containing a -1 with the presumption that the login procedure and password verification was successful. If the application needs to track conditional login attempts, then the session value can be initialized to a positive value and the 'validate' function (below) will return a false (undef) for 'user' when called with a SCALAR return value. The application must set the session value negative for the 'user' string to be returned.

  returns:	session ID or undef

* $var = clean($tainted);

Clean a tainted variable;

  input:	tainted var
  returns:	clean var

* $user=validate($session_dir,$sess_id,$secret,\$error,$expire);

* ($user,$content,$file)=validate($session_dir,$sess_id,$secret,\$error,$expire);

Validate a current session. The session directory is swept for sessions that have exceeded the expire time (seconds), then checked for the presence of a matching session. On error, a descriptive message is placed in the external scalar $error and undef is returned.

  input:	session directory path,
		session ID,
		secret key for MAC,
		pointer to error,
		expire (seconds) [optional]
			default = 15 minutes

  returns:	scalar: user name or undef
		array: (user,contents,sess file)
			or ()

NOTE: in SCALAR mode, the return value will always be false if the session contents are > 0.

* $rv = sesswrap($command,$stdin);

Execute a session wrap command and return results.

  input:	command string,
		stdin string [optional]
  returns:	wrapper output

The wrapper is opened with the command string in it's command line. $stdin, if any, is written to the wrapper's STDIN.

For calls which have a $stdin argument, this routine uses 'fork' and spawns a child httpd process. The routine is enhanced for modperl to properly kill off the child

	none

	encode
	decode
	mac
	new_ses
	validate
	sesswrap

Copyright 2003 - 2005 , Michael Robinton <michael@bizsystems.com>

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

Michael Robinton <michael@bizsystems.com>