Validate issuer on logout requests/responses if configured

README.md

@@ -125,6 +125,8 @@ type Profile = {
   * `validateInResponseTo`: if truthy, then InResponseTo will be validated from incoming SAML responses
   * `requestIdExpirationPeriodMs`: Defines the expiration time when a Request ID generated for a SAML request will not be valid if seen in a SAML response in the `InResponseTo` field.  Default is 8 hours.
   * `cacheProvider`: Defines the implementation for a cache provider used to store request Ids generated in SAML requests as part of `InResponseTo` validation.  Default is a built-in in-memory cache provider.  For details see the 'Cache Provider' section.
+ * **Issuer Validation**
+  * `samlIssuer`: if provided, then the IdP issuer will be validated for incoming Logout Requests/Responses
  * **Passport**
   * `passReqToCallback`: if truthy, `req` will be passed as the first argument to the verify callback (default: `false`)
   * `name`: Optionally, provide a custom name. (default: `saml`). Useful If you want to instantiate the strategy multiple times with different configurations,

lib/passport-saml/saml.js

@@ -845,12 +845,14 @@ SAML.prototype.verifyLogoutResponse = function (doc) {
 };
 
 SAML.prototype.verifyIssuer = function (samlMessage) {
-  var issuer = samlMessage.Issuer;
-  if (issuer && this.options.samlIssuer) {
-    if (issuer[0] !== this.options.samlIssuer && issuer[0]._ !== this.options.samlIssuer)
-      throw 'Unknown SAML issuer. Expected: ' + this.options.samlIssuer + ' Received: ' + issuer[0];
-  } else {
-    throw 'Missing SAML issuer';
+  if(this.options.samlIssuer) {
+    var issuer = samlMessage.Issuer;
+    if (issuer) {
+      if (issuer[0] !== this.options.samlIssuer && issuer[0]._ !== this.options.samlIssuer)
+        throw 'Unknown SAML issuer. Expected: ' + this.options.samlIssuer + ' Received: ' + issuer[0];
+    } else {
+      throw 'Missing SAML issuer';
+    }
   }
 };