MasCanc2.0

From its name, it sounds good , but really complicated! I had two lazy hours during my last working day and I started to play with Net:erver:reFork and with GSSAPI. They are Perl module (the language of the future, for me! ). So I created this server that does nothing but it authenticates with GSSAPI. It will be a good starting point for the future. I used the gss-client pre of the GSSAPI distribution. The server is this:

#!/usr/bin/perl 
package MyPackage;

use base qw(Net:erver:reFork);
use strict;
use warnings;

use Getopt::Long;
use Sys::Hostname;


use GSSAPI;
use MIME::Base64;

use IO:ocket::INET;


my $self = shift;
my $keytabfile;
$keytabfile = "./ciccio.keytab";
$ENV{KRB5_KTNAME} = "FILE:".$keytabfile;
if (! -r $keytabfile) 
{
    die "Cannot read ". $keytabfile .": $!";
}

print STDERR "SERVER set environment variable KRB5_KTNAME to " . $ENV{KRB5_KTNAME} . "\n";


sub process_main
{
    my $self = shift;
    while () 
    {
	
        s/\r?\n$//;
        print "You said \"$_\"\r\n"; # basic echo
        last if /quit/i;
    }
    
}

sub process_request
{
    
#
# Servers need keytab files, the only standard so far is /etc/krb5.keytab.
# That's the file meant to contain keys for the local machine. It is readable
# only by root for security reasons. In this case the name is host@machinename.
#


    

    my $error = 0;
    
    while (! $error) {
	
	my $server_context;
	print  STDERR "\nSERVER::waiting for request ...\n";


	print STDERR "SERVER::accepted connection from client ...\n";
	my $gss_input_token = ;
	

	print  STDERR "SERVER::received token (length is " . length($gss_input_token) . ")n";

	$gss_input_token = depre_base64($gss_input_token);
	
	if (length($gss_input_token) ) {
	    my $status = GSSAPI::Context::accept($server_context,
						 GSS_C_NO_CREDENTIAL,
						 $gss_input_token,
						 GSS_C_NO_CHANNEL_BINDINGS,
						 my $gss_client_name,
						 my $out_mech,
						 my $gss_output_token,
						 my $out_flags,
						 my $out_time,
						 my $gss_delegated_cred);
	    
	    $status or  gss_exit("Unable to accept security context", $status);
	    my $client_name;
	    $status = $gss_client_name->display($client_name);
	    $status or  gss_exit("Unable to display client name", $status);
	    print  STDERR "SERVER::authenticated client name is $client_name\n" if $client_name;
	    
	    if($gss_output_token) {
		print  STDERR "SERVER::Have mutual token to send ...\n";
		print  STDERR "SERVER::GSS token size: " . length($gss_output_token) . "\n";
		
		#
		# $gss_output_token is binary data
		#
		
		my $enc_token = enpre_base64($gss_output_token, '');
		
		print "$enc_token\n";
		print  STDERR "SERVER::sent token (length is " . length($gss_output_token) . ")\n";
	    }
	}
	
	else
	{
	    print STDERR "SERVER::Token fails";
	    exit;
	}
	# Client is authenticated
	process_main();

    }
    
    print "SERVER::exiting after error\n";
    
################################################################################
    
    
    
    
    
} #process request



sub gss_exit {
  my $errmsg = shift;
  my $status = shift;

  my @major_errors = $status->generic_message();
  my @minor_errors = $status->specific_message();

  print STDERR "$errmsgn";
  foreach my $s (@major_errors) {
    print STDERR "  MAJOR::$s\n";
  }
  foreach my $s (@minor_errors) {
    print STDERR "  MINOR::$s\n";
  }
  return 1;
}



MyPackage->run(port => 3000);