1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
|
# --
# Copyright (C) 2001-2021 OTRS AG, https://otrs.com/
# --
# This software comes with ABSOLUTELY NO WARRANTY. For details, see
# the enclosed file COPYING for license information (GPL). If you
# did not receive this file, see https://www.gnu.org/licenses/gpl-3.0.txt.
# --
package Kernel::System::Auth::TwoFactor::GoogleAuthenticator;
use strict;
use warnings;
use Digest::SHA qw(sha1);
use Digest::HMAC qw(hmac_hex);
our @ObjectDependencies = (
'Kernel::Config',
'Kernel::System::DateTime',
'Kernel::System::Log',
'Kernel::System::User',
);
sub new {
my ( $Type, %Param ) = @_;
# allocate new hash for object
my $Self = {};
bless( $Self, $Type );
$Self->{Count} = $Param{Count} || '';
return $Self;
}
sub Auth {
my ( $Self, %Param ) = @_;
# check needed stuff
for my $Needed (qw(User UserID)) {
if ( !$Param{$Needed} ) {
$Kernel::OM->Get('Kernel::System::Log')->Log(
Priority => 'error',
Message => "Need $Needed!"
);
return;
}
}
my $ConfigObject = $Kernel::OM->Get('Kernel::Config');
my $SecretPreferencesKey = $ConfigObject->Get("AuthTwoFactorModule$Self->{Count}::SecretPreferencesKey") || '';
if ( !$SecretPreferencesKey ) {
$Kernel::OM->Get('Kernel::System::Log')->Log(
Priority => 'error',
Message => "Found no configuration for SecretPreferencesKey in AuthTwoFactorModule.",
);
return;
}
# check if user has secret stored in preferences
my %UserPreferences = $Kernel::OM->Get('Kernel::System::User')->GetPreferences(
UserID => $Param{UserID},
);
if ( !$UserPreferences{$SecretPreferencesKey} ) {
# if login without a stored secret key is permitted, this counts as passed
if ( $ConfigObject->Get("AuthTwoFactorModule$Self->{Count}::AllowEmptySecret") ) {
return 1;
}
# otherwise login counts as failed
$Kernel::OM->Get('Kernel::System::Log')->Log(
Priority => 'error',
Message => "Found no SecretPreferencesKey for user $Param{User}.",
);
return;
}
# if we get to here (user has preference), we need a passed token
if ( !$Param{TwoFactorToken} ) {
$Kernel::OM->Get('Kernel::System::Log')->Log(
Priority => 'notice',
Message => "User: $Param{User} two factor authentication failed (TwoFactorToken missing).",
);
return;
}
# generate otp based on secret from preferences
my $OTP = $Self->_GenerateOTP(
Secret => $UserPreferences{$SecretPreferencesKey},
);
# compare against user provided otp
if ( $Param{TwoFactorToken} ne $OTP ) {
# check if previous token is also to be accepted
if ( $ConfigObject->Get("AuthTwoFactorModule$Self->{Count}::AllowPreviousToken") ) {
# try again with previous otp (from 30 seconds ago)
$OTP = $Self->_GenerateOTP(
Secret => $UserPreferences{$SecretPreferencesKey},
Previous => 1,
);
}
if ( $Param{TwoFactorToken} ne $OTP ) {
# log failure
$Kernel::OM->Get('Kernel::System::Log')->Log(
Priority => 'notice',
Message => "User: $Param{User} two factor authentication failed (non-matching otp).",
);
return;
}
}
# log success
$Kernel::OM->Get('Kernel::System::Log')->Log(
Priority => 'notice',
Message => "User: $Param{User} two factor authentication ok.",
);
return 1;
}
sub _GenerateOTP {
my ( $Self, %Param ) = @_;
# algorithm based on RfC 6238
#
# get unix timestamp divided by 30
#
my $DateTimeObject = $Kernel::OM->Create('Kernel::System::DateTime');
my $TimeStamp = $DateTimeObject->ToEpoch();
$TimeStamp = int( $TimeStamp / 30 );
# on request use previous 30-second time period
if ( $Param{Previous} ) {
--$TimeStamp;
}
# extend to 16 character hex value
my $PaddedTimeStamp = sprintf "%016x", $TimeStamp;
# encrypt timestamp with secret
my $PackedTimeStamp = pack 'H*', $PaddedTimeStamp;
my $Base32Secret = $Self->_DecodeBase32( Secret => $Param{Secret} );
my $HMAC = hmac_hex( $PackedTimeStamp, $Base32Secret, \&sha1 );
# now treat hmac to get 6 numerical digits
# Use 4 last bits as offset, then truncate to 4 bytes starting at the offset and remove most significant bit
my $Offset = hex( substr( $HMAC, -1 ) );
my $TruncatedHMAC = hex( substr( $HMAC, $Offset * 2, 8 ) ) & 0x7fffffff;
# use last 6 digits (modulo 1.000.000) as token
my $Token = $TruncatedHMAC % 1000000;
# make sure to use all 6 digits (0-padded)
return sprintf( "%06d", $Token );
}
sub _DecodeBase32 {
my ( $Self, %Param ) = @_;
# based on RfC 3548, code inspired by MIME::Base32
# convert all characters to upper case and remove whitespace (not allowed for base32)
my $Key = uc $Param{Secret};
$Key =~ s{ [ ]+ }{}xmsg;
# turn into binary characters
$Key =~ tr|A-Z2-7|\0-\37|;
# unpack into binary
$Key = unpack 'B*', $Key;
# cut three most significant bits for each byte
$Key =~ s{ 0{3} ( .{5} ) }{$1}xmsg;
# trim string to full 8 bit units
my $Length = length $Key;
if ( $Length % 8 ) {
$Key = substr( $Key, 0, $Length - $Length % 8 );
}
# pack back up
$Key = pack 'B*', $Key;
return $Key;
}
1;
|
