add a hook to modify returned attributes.

Add a hook for modifying the returned attributes
in the SAML request.

inc/class-wp-saml-auth.php

@@ -362,6 +362,12 @@ function () use ( $redirect_to ) {
 			return new WP_Error( 'wp_saml_auth_no_attributes', esc_html__( 'No attributes were present in SAML response. Attributes are used to create and fetch users. Please contact your administrator', 'wp-saml-auth' ) );
 		}
 
+        // Some SAML providers return oddly shaped
+        // responses.
+        $attributes = apply_filters( 
+            'wp_saml_auth_patch_attributes', $attributes,
+             $provider);
+
 		$get_user_by = self::get_option( 'get_user_by' );
 		$attribute   = self::get_option( "user_{$get_user_by}_attribute" );
 		if ( empty( $attributes[ $attribute ][0] ) ) {