Shibboleth

This page details how to install and integrate Shibboleth with EPrints 3.3 on a CentOS 7 operating system. The process should be fairly similar for other modern RedHat-based Linux distributions such as RHEL 7 and Fedora 21/22. However, it will somewhat different for Debian-based Linux, such as Ubuntu and Debian itself and other Linux distributions. Typically, this will just be different package names and different commands to manage applications.

Generally, it is a good idea to run EPrints with HTTPS when using Shibboleth authentication for increased security on the attributes being sent back by the Shibboleth Identity Provider (IdP). Therefore, it is assumed that EPrints has already been set up to use HTTPS and there already exists an ssl/securevhost.conf under the archive directory structure.

Installing Shibboleth

• First, add the Shibboleth repository to your list of Yum repositories:

 root> cd /etc/yum.repos.d/
 root> wget http://download.opensuse.org/repositories/security:shibboleth/CentOS_7/security:shibboleth.repo

• Now you can use Yum to install all package dependencies:

 root> yum install log4shib opensaml shibboleth unixODBC xerces-c xml-security-c xmltooling 

• You may be prompted to accept the importing of the key for the Shibboleth repository, for which you should type y and press enter.

• Once all the packages are installed you will need to specify that the Shibboleth Curl library should be loaded, by adding the following line to /etc/ld.so.conf.d/shibboleth_libs.conf:

 /opt/shibboleth/lib64

• Once you have done that, run ldconfig and then check shibd has no issues:

 root> ldconfig
 root> shibd -t

• shibd -t should return a couple of warning, like those listed below. These are due to it not yet being configured.

 2015-05-11 10:39:01 WARN Shibboleth.Application : insecure cookieProps setting, set to "https" for SSL/TLS-only usage
 2015-05-11 10:39:01 WARN Shibboleth.Application : handlerSSL should be enabled for SSL/TLS-enabled web sites
 2015-05-11 10:39:01 WARN Shibboleth.Application : no MetadataProvider available, configure at least one for standard SSO usage
 overall configuration is loadable, check console for non-fatal problems

• If there are no other warning or error messages from shibd -t, you can start it properly and check to make sure it is running.

 root> systemctl start shibd.service
 root> ps aux | grep shib
 shibd    29338  0.4  0.7 419784 15024 ?        Ssl  11:16   0:00 /usr/sbin/shibd -p /var/run/shibboleth/shibd.pid -f -w 30
 root     29345  0.0  0.0 112640   940 pts/2    S+   11:17   0:00 grep --color=auto -i shib

Configuring Shibboleth

• Replace /etc/shibboleth/shibboleth2.xml with the following. Substitute foo.eprints.org for the hostname of your EPrints repository, https://shib.foo.example.org/idp/shibboleth with the entity ID for you Shibboleth IdP and foo in the pathname of files with the name or your repository (e.g. foo/attribute-map.xml becomes myrepo/attribute-map.xml).

 <SPConfig xmlns="urn:mace:shibboleth:2.0:native:sp:config"
   xmlns:conf="urn:mace:shibboleth:2.0:native:sp:config"
   xmlns:saml="urn:oasis:names:tc:SAML:2.0:assertion"
   xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol"    
   xmlns:md="urn:oasis:names:tc:SAML:2.0:metadata"
   clockSkew="180">
 
   <ApplicationDefaults entityID="https://foo.eprints.org/shibboleth"
                        REMOTE_USER="eppn persistent-id targeted-id">
 
     <Sessions lifetime="28800" timeout="3600" relayState="ss:mem"
                 checkAddress="false" handlerSSL="true" cookieProps="https">
       <SSO entityID="https://shib.foo.example.org/idp/shibboleth">
             SAML2 SAML1
       </SSO>
       <Logout>SAML2 Local</Logout>
       <Handler type="MetadataGenerator" Location="/Metadata" signing="false"/>
       <Handler type="Status" Location="/Status" acl="127.0.0.1 ::1"/>
       <Handler type="Session" Location="/Session" showAttributeValues="false"/>
       <Handler type="DiscoveryFeed" Location="/DiscoFeed"/>
     </Sessions>
 
     <Errors supportContact="root@localhost" helpLocation="/about.html" styleSheet="/shibboleth/main.css"/>
     <MetadataProvider type="XML" file="foo/idp-metadata.xml"/>
     <AttributeExtractor type="XML" validate="true" reloadChanges="false" path="foo/attribute-map.xml"/>
     <AttributeResolver type="Query" subjectMatch="true"/>
     <AttributeFilter type="XML" validate="true" path="attribute-policy.xml"/>
     <CredentialResolver type="File" key="foo/sp-key.pem" certificate="foo/sp-cert.pem"/>
 
   </ApplicationDefaults>
 
   <SecurityPolicyProvider type="XML" validate="true" path="security-policy.xml"/>
   <ProtocolProvider type="XML" validate="true" reloadChanges="false" path="protocols.xml"/>
   
 </SPConfig>

• Create the directory /etc/shibboleth/foo, substituting foo for your repository name.

 root> mkdir /etc/shibboleth/foo

• Copy attribute-map.xml into this new directory.

 cp /etc/shibboleth/attribute-map.xml /etc/shibboleth/foo/

• Temporarily rename sp-cert.pem and sp-key.pem in /etc/shibboleth/ to sp-cert.pem.old and sp-key.pem.old.

 root> cd /etc/shibboleth
 root> mv sp-cert.pem sp-cert.pem.old
 root> mv sp-key.pem sp-key.pem.old

• Run keygen.sh from the /etc/shibboleth/ directory, as follows replacing foo.eprints.org with your EPrints repository hostname.

 root> cd /etc/shibboleth
 root> ./keygen.sh -f -h foo.eprints.org -e https://foo.eprints.org/shibboleth

• Move the new sp-cert.pem and sp-key.pem to /etc/shibboleth/foo/ amd move the .old files back in place:

 root> cd /etc/shibboleth
 root> mv sp-cert.pem sp-key.pem foo/
 root> mv sp-cert.pem.old sp-cert.pem
 root> mv sp-key.pem sp-key.pem

• Check that sp-cert.pem and sp-key.pem in /etc/shibboleth/foo/ still have the owner and group shibd.

 root> ls -l /etc/shibboleth/foo/sp-*
 -rw-r--r-- 1 shibd shibd 1192 May  6 19:04 /etc/shibboleth/foo/sp-cert.pem
 -rw------- 1 shibd shibd 1708 May  6 19:04 /etc/shibboleth/foo/sp-key.pem

• Use wget to download the metadata from your Shibboleth IdP (e.g. shib.foo.example.org) to the /etc/shibboleth/foo/ directory.

 root> wget -O /etc/shibboleth/foo/idp-metadata.xml https://shib.foo.example.org/idp/shibboleth

Configuring Apache and EPrints

N.B. All these actions should be carried out by the eprints user, except when prepended with root> which means the command should be run as the root user.

• Add the following configuration to your archive's ssl/securevhost.conf, after the Include /opt/eprints3/cfg/apache_ssl/foo.conf, substituting foo for your archive's name where appropriate. (This assumes you are running Apache 2.4 or greater).

Alias /shibboleth /opt/eprints3/archives/foo/shibboleth
<Location "/shibboleth">
  SetHandler perl-script
  PerlHandler ModPerl::Registry
  PerlSendHeader Off
  Options ExecCGI FollowSymLinks

  AuthType shibboleth
  ShibRequestSetting requireSession 1
  require shib-session
</Location>

<Location /cgi/shibboleth>
  AuthType shibboleth
  ShibRequestSetting requireSession 1
  require shib-session
</Location>

• Copy the following code into your archive (e.g. /opt/eprints3/archives/foo/) as cgi/shibboleth.

use EPrints;
use strict;
my $session = new EPrints::Session;
exit( 0 ) unless( defined $session );

$session->send_http_header( content_type=>"text/html" );

print "<html><head/><body><code>\n";

foreach my $key (sort keys(%ENV)) {
  print "<p>$key = $ENV{$key}</p>";
}
 
print "</code></body></html>";
$session->terminate;
exit;

• Now restart Shibboleth and Apache:

 root> systemctl restart shibd.service
 root> apachectl restart

• In a web browser go the /cgi/shibboleth page for your repository, (e.g. https://foo.eprints.org/cgi/shibboleth). You should be redirected to an error page for your your Shibboleth IdP (e.g. https://shib.foo.example.org/idp/profile/SAML2/Redirect/SSO?...).

• If instead you are displayed with a list of key values or are forbidden to access the page, you have not configured Apache properly, if so, see Apache_Configuration_Issues under Troubleshooting. If you see an error message like the one below, you have not set up Shibboleth properly, if so, see Shibboleth_Configuration_Issues under Troubleshooting.

opensaml::saml2md::MetadataException
The system encountered an error at Wed May 6 15:19:27 2015
To report this problem, please contact the site administrator at root@localhost.
Please include the following message in any email:
opensaml::saml2md::MetadataException at (http://foo.eprints.org/cgi/shibboleth)
Unable to locate metadata for identity provider (https://shib.foo.example.org/idp/shibboleth)

• Next, copy the following code into your archive (e.g. /opt/eprints3/archives/foo/) as cfg/cfg.d/zz_shibboleth.pl. This is needed to redirect login and logout to use Shibboleth rather than local login.

$c->{get_login_url} = sub {
  my( $session, $target ) = @_;

  # preserve CGI params
  $session->read_params;
  $target = $session->get_url(
    host => 1,
    path => "auto",
    query => 1,
  );

  my $url = URI->new( $session->config( "https_url" )  . "/shibboleth/login" );
  $url->query_form( target => "$target" );
  return "$url";
};

$c->{on_logout} = sub {
  my( $session ) = @_;
  my $query = $session->query;
  return unless defined $query;

  # remove _shibsession_ cookie
  my( $shibname, $shibvalue );
  for( $query->cookie() ) {
    if( $_ =~ /^_shibsession/ ) {
      $shibname = $_;
      $shibvalue = $query->cookie( $shibname );
    }
  }

  my $cookie = $query->cookie(
    -name    => $shibname,
    -path    => "/",
    -value   => "",
    -host  => $session->config("cookie_domain"),
    -expires => "-1d",
  );
  EPrints::Apache::AnApache::header_out(
    $session->{request},
    "Set-Cookie" => $cookie 
  );
};

push @{$c->{rewrite_exceptions}}, "/shibboleth/";

• Create a folder at the top level of your archive (e.g. /opt/eprints3/archives/foo/) called shibboleth and copy the main CSS file for Shibboleth into this folder:

eprints> mkdir /opt/eprints3/archives/foo/shibboleth/
eprints> cp /usr/share/shibboleth/main.css /opt/eprints3/archives/foo/shibboleth/

• Now, copy the following code into your archive (e.g. /opt/eprints3/archives/foo/) as shibboleth/login. This is the most basic login script that should work with the minimal attributes any Shibboleth IdP returns; logging in users with existing accounts and creating new accounts for users logging in for the first time. Look under the Customisation section for advice on how to modify this script to meet your requirements.

use EPrints;
use strict;

my $session = EPrints::Session->new();
my $url = $session->param( "target" );
$url = $session->get_repository->get_conf( "userhome" ) unless EPrints::Utils::is_set( $url );

my $user = &get_user;

if( defined $user ) {
  $user->set_value( "last_login", EPrints::Time::get_iso_timestamp() );
  $user->commit;

  EPrints::DataObj::LoginTicket->expire_all( $session );
  $session->dataset( "loginticket" )->create_dataobj({
    userid => $user->id,
  })->set_cookies();

  $session->redirect( $url );
}
else {
  $session->redirect( $session->get_repository->get_conf( "base_dir" ) . "/account_required.html");
}

$session->terminate;
  
sub get_user {
  my ( $username, $email ) = ( undef, );
  if( $ENV{eppn} ) {
   ( $username ) = split( /@/, $ENV{eppn}, 2);
   $username = lc( $username );
   $email = $ENV{eppn};
  }
  return unless EPrints::Utils::is_set( $username );
  my $user = $session->user_by_username( $username );
  $user->set_value( "email", $email );
  $user->commit;
  return $user;
}

• Next, add the following markup to cfg/lang/en/static/account_required.xpage under your archive (e.g. /opt/eprints3/archives/foo/). Substituting staff and students of the University of Foo to describe to which particular group of people logged in access is restricted.

<?xml version="1.0" standalone="no" ?>
<!DOCTYPE page SYSTEM "entities.dtd" >
<xpage:page xmlns="http://www.w3.org/1999/xhtml" xmlns:xpage="http://eprints.org/ep3/xpage" xmlns:epc="http://eprints.org/ep3/control">
<xpage:title>Login Failed</xpage:title>
<xpage:body>
   <p style='text-align: center;'>Please note that only staff and students of the University of Foo may log in to <epc:phrase ref="archive_name" /></p>
</xpage:body>
</xpage:page>

• Now, reload Apache.

 root> apachectl reload

• In a web browser go to the /shibboleth/login page for your repository, (e.g. https://foo.eprints.org/shibboleth/login). Like before with /cgi/shibboleth you should be taken to your Shibboleth IdP's site albeit displaying an error message.

• The Shibboleth IdP shows an error message because EPrints as a Shibboleth Service Provider is not yet registered with it. To do this you need to send the administrator of the Shibboleth IdP the metadata for your Service Provider. By default this is not externally accessible, so you will need to do a wget from the command line:

 wget --no-check-certificate -O - -o /dev/null https://localhost/Shibboleth.sso/Metadata | xmllint --format - > ~/sp-metadata.xml

• If you get no error messages, this command will have saved you Shibboleth Service Provider metadata in a file in your home directory called sp-metadata.xml, which you can now email to the administrator of the Shibboleth Identity Provider and then wait for them to get back to you to tell you it has been registered.

• Once registered, use a web browser to go to /shibboleth/login page for your repository, (e.g. https://foo.eprints.org/shibboleth/login) again. This time you should be prompted for a username and password on the Shibboleth IdP site. Once you have typed this in and clicked to login, you should be returned to EPrints on the /cgi/users/home page for your repository. If not, see Login Issues under Troubleshooting below.

Troubleshooting

Apache Configuration Issues

To be added.

Shibboleth Configuration Issues

To be added.

Login Issues

To be added.

Customisation

Shibboleth /etc/shibboleth/foo/attribute-map.xml config

To be added.

EPrints /shibboleth/login script

To be added.

Further Information

• Older instructions of how to set up EPrints for Shibboleth using UK Access management Federation discovery service is available here.

• For general information about installing and configuring Shibboleth click here.