#!/usr/local/bin/perl
package Authen::NTLM;
use Authen::NTLM::DES;
use Authen::NTLM::MD4;
use MIME::Base64;
use vars qw($VERSION @ISA @EXPORT);
require Exporter;
=head1 NAME
Authen::NTLM - An NTLM authentication module
=head1 SYNOPSIS
use Mail::IMAPClient;
use Authen::NTLM;
my $imap = Mail::IMAPClient->new(Server=>'imaphost');
ntlm_user($username);
ntlm_password($password);
$imap->authenticate("NTLM", Authen::NTLM::ntlm);
:
$imap->logout;
ntlm_reset;
:
=head1 DESCRIPTION
This module provides methods to use NTLM authentication. It can
be used as an authenticate method with the Mail::IMAPClient module
to perform the challenge/response mechanism for NTLM connections
or it can be used on its own for NTLM authentication with other
protocols (eg. HTTP).
The implementation is a direct port of the code from F<fetchmail>
which, itself, has based its NTLM implementation on F<samba>. As
such, this code is not especially efficient, however it will still
take a fraction of a second to negotiate a login on a PII which is
likely to be good enough for most situations.
=head2 FUNCTIONS
=over 4
=item ntlm_domain()
Set the domain to use in the NTLM authentication messages.
Returns the new domain. Without an argument, this function
returns the current domain entry.
=item ntlm_user()
Set the username to use in the NTLM authentication messages.
Returns the new username. Without an argument, this function
returns the current username entry.
=item ntlm_passwd()
Set the password to use in the NTLM authentication messages.
Returns the new password. Without an argument, this function
returns the current password entry.
=item ntlm_reset()
Resets the NTLM challenge/response state machine so that the next
call to C<ntlm()> will produce an initial connect message.
=item ntlm()
Generate a reply to a challenge. The NTLM protocol involves an
initial empty challenge from the server requiring a message
response containing the username and domain (which may be empty).
The first call to C<ntlm()> generates this first message ignoring
any arguments.
The second time it is called, it is assumend that the argument is
the challenge string sent from the server. This will contain 8
bytes of data which are used in the DES functions to generate the
response authentication strings. The result of the call is the
final authentication string.
If C<ntlm_reset()> is called, then the next call to C<ntlm()> will
start the process again allowing multiple authentications within
an application.
=back
=head1 AUTHOR
Mark Bush <Mark.Bush@bushnet.demon.co.uk> - perl port
Eric S. Raymond - author of fetchmail
Andrew Tridgell and Jeremy Allison for SMB/Netbios code
=head1 SEE ALSO
L<perl>, L<Mail::IMAPClient>
=cut
$VERSION = "1.02";
@ISA = qw(Exporter);
@EXPORT = qw(ntlm ntlm_domain ntlm_user ntlm_password ntlm_reset);
my $domain = "";
my $user = "";
my $password = "";
my $str_hdr = "vvV";
my $hdr_len = 8;
my $ident = "NTLMSSP";
my $msg1_f = 0x0000b207;
my $msg1 = "Z8VV";
my $msg1_hlen = 16 + ($hdr_len*2);
my $msg2 = "Z8Va${hdr_len}Va8a8a${hdr_len}";
my $msg2_hlen = 12 + $hdr_len + 20 + $hdr_len;
my $msg3 = "Z8V";
my $msg3_tl = "V";
my $msg3_hlen = 12 + ($hdr_len*6) + 4;
my $state = 0;
sub ntlm_domain
{
if (@_)
{
$domain = shift;
}
return $domain;
}
sub ntlm_user
{
if (@_)
{
$user = shift;
}
return $user;
}
sub ntlm_password
{
if (@_)
{
$password = shift;
}
return $password;
}
sub ntlm_reset
{
$state = 0;
}
sub ntlm
{
my ($challenge) = @_;
my ($flags, $user_hdr, $domain_hdr,
$u_off, $d_off, $c_info, $lmResp, $ntResp, $lm_hdr,
$nt_hdr, $wks_hdr, $session_hdr, $lm_off, $nt_off,
$wks_off, $s_off, $u_user);
my $response;
if ($state)
{
$challenge =~ s/^\s*//;
$challenge = decode_base64($challenge);
$c_info = &decode_challenge($challenge);
$u_user = &unicode($user);
$domain = substr($c_info->{buffer}, 0, $c_info->{domain}{len});
$response = pack($msg3, $ident, 3);
$lmResp = &lmEncrypt($c_info->{data});
$ntResp = &ntEncrypt($c_info->{data});
$lm_off = $msg3_hlen;
$nt_off = $lm_off + length($lmResp);
$d_off = $nt_off + length($ntResp);
$u_off = $d_off + length($domain);
$wks_off = $u_off + length($u_user);
$s_off = $wks_off + length($u_user);
$lm_hdr = &hdr($lmResp, $msg3_hlen, $lm_off);
$nt_hdr = &hdr($ntResp, $msg3_hlen, $nt_off);
$domain_hdr = &hdr($domain, $msg3_hlen, $d_off);
$user_hdr = &hdr($u_user, $msg3_hlen, $u_off);
$wks_hdr = &hdr($u_user, $msg3_hlen, $wks_off);
$session_hdr = &hdr("", $msg3_hlen, $s_off);
$flags = pack($msg3_tl, $c_info->{flags});
$response .= $lm_hdr . $nt_hdr . $domain_hdr . $user_hdr .
$wks_hdr . $session_hdr . $flags .
$lmResp . $ntResp . $domain . $u_user . $u_user;
}
else # first response;
{
$response = pack($msg1, $ident, 1, $msg1_f);
$u_off = $msg1_hlen;
$d_off = $u_off + length($user);
$user_hdr = &hdr($user, $msg1_hlen, $u_off);
$domain_hdr = &hdr($domain, $msg1_hlen, $d_off);
$response .= $user_hdr . $domain_hdr . $user . $domain;
$state = 1;
}
return encode_base64($response, "");
}
sub hdr
{
my ($string, $h_len, $offset) = @_;
my ($res, $len);
$len = length($string);
if ($string)
{
$res = pack($str_hdr, $len, $len, $offset);
}
else
{
$res = pack($str_hdr, 0, 0, $offset - $h_len);
}
return $res;
}
sub decode_challenge
{
my ($challenge) = @_;
my $res;
my (@res, @hdr);
$res->{buffer} = substr($challenge, $msg2_hlen);
$challenge = substr($challenge, 0, $msg2_hlen);
@res = unpack($msg2, $challenge);
$res->{ident} = $res[0];
$res->{type} = $res[1];
@hdr = unpack($str_hdr, $res[2]);
$res->{domain}{len} = $hdr[0];
$res->{domain}{maxlen} = $hdr[1];
$res->{domain}{offset} = $hdr[2];
$res->{flags} = $res[3];
$res->{data} = $res[4];
$res->{reserved} = $res[5];
$res->{empty_hdr} = $res[6];
return $res;
}
sub unicode
{
my ($string) = @_;
my ($reply, $c, $z);
$z = sprintf "%c", 0;
foreach $c (split //, $string)
{
$reply .= $c . $z;
}
return $reply;
}
sub NTunicode
{
my ($string) = @_;
my ($reply, $c);
foreach $c (map {ord($_)} split(//, $string))
{
$reply .= pack("v", $c);
}
return $reply;
}
sub lmEncrypt
{
my ($data) = @_;
my $p14 = substr($password, 0, 14);
$p14 =~ tr/a-z/A-Z/;
$p14 .= "\0"x(14-length($p14));
my $p21 = E_P16($p14);
$p21 .= "\0"x(21-length($p21));
my $p24 = E_P24($p21, $data);
return $p24;
}
sub ntEncrypt
{
my ($data) = @_;
my $p21 = &E_md4hash;
$p21 .= "\0"x(21-length($p21));
my $p24 = E_P24($p21, $data);
return $p24;
}
sub E_md4hash
{
my $wpwd = &NTunicode($password);
my $p16 = mdfour($wpwd);
return $p16;
}
1;