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The biggest issue is that is not possible to provision accounts for customers in OTRS before they have logged in. This is because there is no way of knowing a user's details until they have authenticated. To overcome this I wrote two a new authentication modules module for OTRS that creates customer accounts on the fly (auto-provisioning).

Below is the recipe for getting OTRS to work with federated authentication using Ubuntu 14.04, OTRS 3.3.8 and mod_auth_mellon 0.7. If you manage to implement it on another combination of software, please let me know.

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Code Block
themeMidnight
languageerl
        MellonEnable "info"
        MellonSecureCookie On
        MellonSessionDump Off
        MellonUser eduPersonPrincipalName
        MellonSamlResponseDump Off
        MellonEndpointPath "/mellon"
        MellonSPPrivateKeyFile /etc/apache2/mellon/sp.key
        MellonSPCertFile /etc/apache2/mellon/sp.crt
        MellonIdPMetadataFile /etc/apache2/mellon/idp.xml
        # To avoid security holes, first unset any existing header

 

 

As you can see, the attribute eduPersonPrincipalName is being used as the username. This is the attribute that should always be sent by the IdP. In other words, you have to make that authentication doesn't go through when there is an eduPersonPrincipalName. mod_auth_mellon populate the REMOTE_USER environment variable with the value of this SAML attribute.

Info

Keep in mind that eduPersonPrincipalName might work well in a controller environment, such a a national identity federation, where the attribute is always present, validated, etc. It might not be so smart if you use a SAML proxy, in which case you could end up with different users with the same eduPersonPrincipalName.

 

By this time, you should be able to download the Service Provider metadata from https://otrs.example.com/mellon/metadata, and use it to add it to your IdP, thereby creating a trust relationship.

And once that is done, you should be able to authenticate by going to https://otrs.example.org/mellon.

 

Adding the new module to OTRS

 

Create the file Kernel/System/CustomerAuth/HTTPBasicAuthMellon.pm and copy the code below in it:

Code Block
themeMidnight
languageperl
# --
# Kernel/System/CustomerAuth/HTTPBasicAuthMellon.pm
# Provides HTTPBasic authentication for use with Apache's mod_auth_mellon.
# This module auto-provisions customer users.
# Dick Visser <visser@terena.org> 2014-08-22
# Copyright (C) TERENA, http://www.terena.org
# --
# This software comes with ABSOLUTELY NO WARRANTY. For details, see
# the enclosed file COPYING for license information (AGPL). If you
# did not receive this file, see http://www.gnu.org/licenses/agpl.txt.
# --
package Kernel::System::CustomerAuth::HTTPBasicAuthMellon;
use strict;
use warnings;
sub new {
    my ( $Type, %Param ) = @_;
    # allocate new hash for object
    my $Self = {};
    bless( $Self, $Type );
    # check needed objects
    for (qw(LogObject ConfigObject DBObject MainObject EncodeObject)) {
        $Self->{$_} = $Param{$_} || die "No $_!";
    }
    $Self->{CustomerUserObject} = Kernel::System::CustomerUser->new( %{$Self} );
    # Mellon environment vars
    $Self->{MailEnvVar}
        = $Self->{ConfigObject}->Get( 'Customer::AuthModule::HTTPBasicAuthMellon::MailEnvVar')
	|| 'MELLON_mail';
    $Self->{FirstNameEnvVar}
        = $Self->{ConfigObject}->Get('Customer::AuthModule::HTTPBasicAuthMellon::FirstNameEnvVar')
	|| 'MELLON_givenName';
    $Self->{LastNameEnvVar}
        = $Self->{ConfigObject}->Get( 'Customer::AuthModule::HTTPBasicAuthMellon::LastNameEnvVar')
	|| 'MELLON_sn';
    $Self->{CustomerIDEnvVar}
        = $Self->{ConfigObject}->Get( 'Customer::AuthModule::HTTPBasicAuthMellon::CustomerIDEnvVar')
	|| 'MELLON_customer_id';
    # Debug 0=off 1=on
    $Self->{Debug} = 1;
    $Self->{Count} = $Param{Count} || '';
    return $Self;
}
sub GetOption {
    my ( $Self, %Param ) = @_;
    # check needed stuff
    if ( !$Param{What} ) {
        $Self->{LogObject}->Log( Priority => 'error', Message => "Need What!" );
        return;
    }
    # module options
    my %Option = ( PreAuth => 1, );
    # return option
    return $Option{ $Param{What} };
}
sub Auth {
    my ( $Self, %Param ) = @_;
    # Get attributes values from environment variables
    my $User       = $ENV{REMOTE_USER};
    my $Mail       = $ENV{$Self->{MailEnvVar}} || 'invalid_email@noreply.com';
    my $FirstName  = $ENV{$Self->{FirstNameEnvVar}} || 'first_name';
    my $LastName   = $ENV{$Self->{LastNameEnvVar}} || 'last_name';
    my $CustomerID = $ENV{$Self->{CustomerIDEnvVar}} || 'default_customer';
    my $RemoteAddr = $ENV{REMOTE_ADDR} || 'Got no REMOTE_ADDR env!';
    # return on no user
    if ( !$User ) {
        $Self->{LogObject}->Log(
            Priority => 'notice',
            Message =>
                "No \$ENV{REMOTE_USER}, so not authenticated yet. Redirecting to authenticate (client REMOTE_ADDR: $RemoteAddr).",
        );
        return;
    }
    # replace parts of login
    my $Replace = $Self->{ConfigObject}->Get(
        'Customer::AuthModule::HTTPBasicAuth::Replace' . $Self->{Count},
    );
    if ($Replace) {
        $User =~ s/^\Q$Replace\E//;
    }
    # regexp on login
    my $ReplaceRegExp = $Self->{ConfigObject}->Get(
        'Customer::AuthModule::HTTPBasicAuth::ReplaceRegExp' . $Self->{Count},
    );
    if ($ReplaceRegExp) {
        $User =~ s/$ReplaceRegExp/$1/;
    }
    # Log Apache environment vars in debug mode
    if ( $Self->{Debug} > 0 ) {
        $Self->{LogObject}->Log(
            Priority => 'debug',
            Message => 'Apache environment vars:'
        );
        foreach my $var (sort keys %ENV) {
            $Self->{LogObject}->Log(
                Priority => 'debug',
                Message =>   $var . "=" . $ENV{$var},
            );
        }
    }
    # log
    $Self->{LogObject}->Log(
        Priority => 'notice',
        Message  => "User '$User' Authentication ok (REMOTE_ADDR: $RemoteAddr).",
    );

    # Auto-provisiong.
    # First check if customer exists
    my %UserTest = $Self->{CustomerUserObject}->CustomerUserDataGet( User => $User );
    if (! %UserTest) {
        $Self->{LogObject}->Log(
            Priority => 'notice',
            Message  => "User '$User' doesn't have an account here yet, provisioning it now",
        );
        # Add new customer
        my $newuser = $Self->{CustomerUserObject}->CustomerUserAdd(
            Source         => 'CustomerUser',
            UserFirstname  => $FirstName,
            UserLastname   => $LastName,
            UserCustomerID => $CustomerID,
            UserLogin      => $User,
            UserPassword   => $Self->{CustomerUserObject}->GenerateRandomPassword(),
            UserEmail      => $Mail,
            ValidID        => 1,
        

...

    UserID         => 1,
        

...

 );
 

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...

 

...

 

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}
    # return user
  

...

 

...

 

...

return $User;
}
1;

 

Configuration

When creating a new customer, we also need data for several other fields: first name, last name, e-mail, and customID. Since mod_auth_mellon copies all the SAML attributes into Apache environment variables anyway, we can use them. The module uses the standard SAML attributes (prefixed with MELLON_ because that's their environment variable name) wherever possible:

 Apache environment variable
First nameMELLON_givenName
Last nameMELLON_sn
e-mail addressMELLON_mail
customerIDMELLON_otrs_customer_id

 

You can override these values in your OTRS configuration.

Your

 

 

As you can see, the attribute eduPersonPrincipalName is being used as the username. This is the attribute that should always be send by the IdP.

Note

I had problems getting things to work if the environment variable was REMOTE_USER. I think there is some issue with mod_auth_mellon trying to overwrite that, but I didn't have time to find the cause. It worked with everything else than REMOTE_USER though (wink)

 

By this time, you should be able to download the Service Provider metadata from https://otrs.example.com/mellon/metadata, and use it to add it to your IdP, thereby creating a trust relationship.

Once that is done, you should be able to authenticate by going to https://otrs.example.org/mellon.

 

Adding the new methods to OTRS

Download the archive containing the methods and unpack it over your OTRS tree. It contains two files, both called HTTPBasicAuthMellon.pm, which go into System/Kernel/Auth and System/Kernel/CustomerAuth.

Once they're there, change your configuration (System/Config.pm) to include these statements:

 

Code Block
themeMidnight
languageperl
    # Customer Auth 
    $Self->{'Customer::AuthModule'} = 'Kernel::System::CustomerAuth::HTTPBasicAuthMellon';
    # Customer user are automagically created (auto-provisioned) using the environment vars below Uncomment to override the environment vars to be used
    $Self->{'Customer::AuthModule::HTTPBasicAuthMellon::UsernameEnvVar'} = 'MELLON_eduPersonPrincipalName';
    $Self->{'Customer::AuthModule::HTTPBasicAuthMellon::UsernameEnvVarMailEnvVar'} = 'MELLON_eduPersonPrincipalNamemail';
    $Self->{'Customer::AuthModule::HTTPBasicAuthMellon::MailEnvVarFirstNameEnvVar'} = 'MELLON_mailgivenName';
    $Self->{'Customer::AuthModule::HTTPBasicAuthMellon::FirstNameEnvVarLastNameEnvVar'} = 'MELLON_givenNamesn';
    $Self->{'Customer::AuthModule::HTTPBasicAuthMellon::LastNameEnvVarCustomerIDEnvVar'} = 'MELLON_otrs_sncustomer_id';
    $Self->{'CustomerPanelLoginURL'}    = 'https://otrs.example.com/mellon/login?ReturnTo=/customer.pl';
    $Self->{'CustomerPanelLogoutURL'}   = 'https://otrs.example.com/mellon/logout?ReturnTo=http://www.terena.org';
    # Because auto-provisioned users will all have the same e-mail address
    $Self->{CustomerUser}->{CustomerUserEmailUniqCheck} = 0;

    # Agents are NOT auto-provisioned. The will have to be created manually.
    # To find their username, they could first log in as a customer, so that you can see their username
    # in the Customer User Manager overview.
    $Self->{'AuthModule'} = 'Kernel::System::Auth::HTTPBasicAuthMellon';
    # Only this one is needed
    $Self->{'AuthModule::HTTPBasicAuthMellon::UsernameEnvVar'} = 'MELLON_eduPersonPrincipalNameHTTPBasicAuth';
    $Self->{'LoginURL'} = 'https://otrs.example.com/mellon/login?ReturnTo=/index.pl';
    $Self->{'LogoutURL'}        = 'https://otrs.example.com/mellon/logout?ReturnTo=http://www.terena.org';

 

At this point, you should be able to log in to the site as an admin with your new account.

If you log in to the customer page, your account will be automatically created.

 

I don't even trust my own Perl skills, so use all of this with care (smile)