Does not validate Signature when authenticating via HTTP redirect

[Yanchek99]

When using HTTP-Redirect Binding for SSO, the Signature Algorithm and the Signature are parameters in the request. This gem does not currently support getting those attributes from the request and validating them. Only when the data comes from a HTTP post is the Signature and Algorithm part of the AuthRequest xml. Therefore no signing validation is done when Authentication is happening from an HTTP Redirect.

Example:

Started GET "/saml/auth?SAMLRequest=jZJRb9sgFIXf9ysQ7wSwldhGcaqsUbVI3RY17h76MlFMEiR88QC3278fsRep09aqvHHvubrfObrLq5%2BdRU%2FaB%2BOgxnzGMNKgXGvgWOP75oaU%2BGq1DLKzvVgP8QR3%2BsegQ0RpDoIYGzUePAgngwkCZKeDiErs159vRTZjovcuOuUsnkbeFssQtI%2BJBaPtpsbfi7zNVJVlcp7njB2YKuYZk8Wc80KVRV6ydrGQVXV45Bh9u7jIzi62IQx6CyFKiKnE%2BIKwnLCq4QvBS8GrB4x2f9A%2BGpgMv4X2OImC%2BNQ0O7L7um8wWl9wrx2EodN%2Br%2F2TUfr%2B7rbGpxh7Qal1StqTC1GUrGQUo02Kz4CMI%2Bs%2FomST0XOsVKa48ZS9GN34F6G%2FN8bV%2Fymee6IcRA2R9nY4Ggi0M2Ccl3DU5LyAZIyE5NemrzkCcUCX9AXL5Si%2BpOXbzc5Zo36htbXu%2BdprGXWNox80RjfOdzK%2BjstnfKyYlhxGqRgg9FqZg9Et%2FoBeeXQ10fx9lavf&RelayState=testValidate&SigAlg=http%3A%2F%2Fwww.w3.org%2F2001%2F04%2Fxmldsig-more%23rsa-sha256&Signature=eIHdZLz5VL0OF6ZkieDWcEDFWQ40yyKavS2jQMj1EplB8hsRbsplOyq%2B8gj5F91UBJIfaz8jKNXULDyeY7iXjX4kIDUqJuX69CgY7GS%2Fb%2FTpsRc7l4YDyhlhzHOH%2B2WSjiMzrofTYhh8zNiXJeXyHHhwvg0EleAJc8Uz2892NXFDWIxXfbY%2FA4cbBqUTz0vvl4q99Kns6v%2BDBHntA52W%2FjgMEed08GGTP2vQewUpT3V3eJb98nHJOqvJzu8qK8YM%2Fv9xGNMc1nvt8UJ8kY8uaLjWVg1ABs0X2mjqDfc5yXHqZQThlSSUBX3N1w%2FvZBzVtYjtkuJVWEpnejazJ8ginw%3D%3D" for 127.0.0.1 at 2016-03-09 09:18:18 -0700
Processing by SamlIdpController#create as HTML
  Parameters: {"SAMLRequest"=>"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", "RelayState"=>"testValidate", "SigAlg"=>"http://www.w3.org/2001/04/xmldsig-more#rsa-sha256", "Signature"=>"eIHdZLz5VL0OF6ZkieDWcEDFWQ40yyKavS2jQMj1EplB8hsRbsplOyq+8gj5F91UBJIfaz8jKNXULDyeY7iXjX4kIDUqJuX69CgY7GS/b/TpsRc7l4YDyhlhzHOH+2WSjiMzrofTYhh8zNiXJeXyHHhwvg0EleAJc8Uz2892NXFDWIxXfbY/A4cbBqUTz0vvl4q99Kns6v+DBHntA52W/jgMEed08GGTP2vQewUpT3V3eJb98nHJOqvJzu8qK8YM/v9xGNMc1nvt8UJ8kY8uaLjWVg1ABs0X2mjqDfc5yXHqZQThlSSUBX3N1w/vZBzVtYjtkuJVWEpnejazJ8ginw=="}

[jphenow]

This seems to be related or is the same as #42, but leaving for now.

[militarpancho]

Hi!, Any advances on this feature?