Simplesamlphp unhandled exception error while using as SP - single-sign-on

Question

After successfully receiving the SAML 2.0 token while using simplesamlphp as a Service Provider I get the following error.
Oct 21 17:30:15 simplesamlphp DEBUG [6b6e3c270f] GenerateGroups - attribute 'eduPersonAffiliation' not found.
Oct 21 17:30:15 simplesamlphp DEBUG [6b6e3c270f] Session: doLogin("default-sp")
Oct 21 17:30:15 simplesamlphp WARNING [6b6e3c270f] Unable to find the SAML 2 binding used for this request.
Oct 21 17:30:15 simplesamlphp WARNING [6b6e3c270f] Request method: 'GET'
Oct 21 17:30:15 simplesamlphp ERROR [6b6e3c270f] SimpleSAML_Error_Error: UNHANDLEDEXCEPTION
Oct 21 17:30:15 simplesamlphp ERROR [6b6e3c270f] Backtrace:
Oct 21 17:30:15 simplesamlphp ERROR [6b6e3c270f] 0 /var/www/simplesamlphp/www/module.php:180 (N/A)
Oct 21 17:30:15 simplesamlphp ERROR [6b6e3c270f] Caused by: Exception: Unable to find the current binding.
Oct 21 17:30:15 simplesamlphp ERROR [6b6e3c270f] Backtrace:
Oct 21 17:30:15 simplesamlphp ERROR [6b6e3c270f] 2 /var/www/simplesamlphp/lib/SAML2/Binding.php:95 (SAML2_Binding::getCurrentBinding)
Oct 21 17:30:15 simplesamlphp ERROR [6b6e3c270f] 1 /var/www/simplesamlphp/modules/saml/www/sp/saml2-acs.php:11 (require)
Oct 21 17:30:15 simplesamlphp ERROR [6b6e3c270f] 0 /var/www/simplesamlphp/www/module.php:135 (N/A)
Oct 21 17:30:15 simplesamlphp ERROR [6b6e3c270f] Error report with id bd213fb5 generated.
My SP is set up like this:
**authsources.php**
'default-sp' => array(
'saml:SP',
'entityID' => NULL,
'idp' => NULL,
'discoURL' => NULL,
'RelayState' => '{link to my application}',
'acs.Bindings' => array(
'urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST',
'urn:oasis:names:tc:SAML:1.0:profiles:browser-post',
),
),
saml20-idp-remote.php
$metadata['https://{idp entity id}'] = array(
'metadata-set' => 'saml20-idp-remote',
'entityid' => 'https://{idp entity id}',
'name' => array(
'en' => 'IDP Name',
'no' => 'IDP name',
),
'description' => 'IDP desc',
'SingleSignOnService' =>
array (
0 =>
array (
'Binding' => 'urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST',
'Location' => '{SSO url}',
),
1 =>
array(
'Binding' => 'urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Artifact',
'Location' => '{SSO url}',
),
),
'SingleLogoutService' => '{SLO url}',
'certFingerprint' => '{the fingerprint}',
);
I am pretty new to Single Sign on. I have also hid the urls for confidentiality but I am not sure if I am missing something or whats causing this error to be thrown. If anyone could help point me in the right direction that would be greatly appreciated. I should also mention I am trying to use https://drupal.org/project/simplesamlphp_auth to hook into my application.
This is an IDP first flow. I am use mysql to store the sessions.

Answer 1

"Unable to find the current binding." means exactly that, that the current binding cannot be determined. Your saml20-idp-remote.php mentions HTTP-POST binding, and your log mentions Request method: 'GET', so probably something goes wrong while posting to https://…/module.php/saml/sp/saml2-acs.php/default-sp.
I'm just doing a wild guess here, but in my experience, the most common cause is a redirecting web server. Maybe you redirect to a different hostname? Do you force HTTPS? Check on the IdP that the URLs for the AssertionConsumerService are correct - they should lead directly to SimpleSamlPhp without any redirect.

Answer 2

I faced same situation.
THe saml entity was pointing to www.mysite.com
in the apache configuration we were redirecting www.mysite.com to mysite.com with redirect code 301, after changing to redirect code 307 to preserve get and post variables it started working fine.
Thanks,
Anubhav