Using the X509 authentication source with simpleSAMLphp
=======================================================
The authX509 module provides X509 authentication with certificate
validation. For now there is only one authentication source:
* authX509userCert Validate against LDAP userCertificate attribute
More validation schemes (OCSP, CRL, local list) might be added later.
Configuring Apache
------------------
This module assumes that the server requests a client certificate, and
stores it in the environment variable SSL_CLIENT_CERT. This can be achieved
with such a configuration:
SSLEngine on
SSLCertificateFile /etc/openssl/certs/server.crt
SSLCertificateKeyFile /etc/openssl/private/server.key
SSLCACertificateFile /etc/openssl/certs/ca.crt
SSLVerifyClient require
SSLVerifyDepth 2
SSLOptions +ExportCertData
Note that SSLVerifyClient can be set to optional if you want to support
both certificate and plain login authentication at the same time (more on
this later).
If your server or your client (or both!) have TLS renegotiation disabled
as a workaround for CVE-2009-3555, then the configuration directive above
must not appear in a <Directory>, <Location>, or in a name-based
<VirtualHost>. You can only use them server-wide, or in <VirtualHost>s
with different IP address/port combinations.
Setting up the authX509 module
------------------------------
The first thing you need to do is to enable the module:
touch modules/authX509/enable
Then you must add it as an authentication source. Here is an
example authsources.php entry:
'x509' => array(
'authX509:X509userCert',
'hostname' => 'ldaps://ldap.example.net',
'enable_tls' => FALSE,
'attributes' => array("cn", "uid", "mail", "ou", "sn"),
'search.enable' => TRUE,
'search.attributes' => array('uid', 'mail'),
'search.base' => 'dc=example,dc=net',
'authX509:x509attributes' => array('UID' => 'uid'),
'authX509:ldapusercert' => array('userCertificate;binary'),
),
The configuration is the same as for the LDAP module, except for
two options:
* x509attributes is used to map a certificate subject attribute to
an LDAP attribute. It is used to find the certificate
owner in LDAP from the certificate subject. If multiple
mappings are provided, any mapping will match (this
is a logical OR). Default is array('UID' => 'uid').
* ldapusercert the LDAP attribute in which the user certificate will
be found. Default is userCertificate;binary. This can
be set to NULL to avoid looking up the certificate in
LDAP.
Uploading certificate in LDAP
-----------------------------
Certificates are usually stored in LDAP as DER, in binary. Here is
how to convert from PEM to DER:
openssl x509 -in cert.pem -inform PEM -outform DER -out cert.der
Here is some LDIF to upload the certificate in the directory:
dn: uid=jdoe,dc=example,dc=net
changetype: modify
add: userCertificate;binary
userCertificate;binary:< file:///path/to/cert.der
Supporting both certificate and login authentication
====================================================
In your Apache configuration, set SSLVerifyClient to optional. Then you
can hack your metadata/saml20-idp-hosted.php file that way:
$auth_source = empty($_SERVER['SSL_CLIENT_CERT']) ? 'ldap' : 'x509';
$metadata = array(
'__DYNAMIC:1__' => array(
'host' => '__DEFAULT__',
'privatekey' => 'server.key',
'certificate' => 'server.crt',
'auth' => $auth_source,
'authority' => 'login',
'userid.attribute' => 'uid',
'logouttype' => 'iframe',
'attributes.NameFormat' =>
'urn:oasis:names:tc:SAML:2.0:attrname-format:uri',
)
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