fix for enveloped signatures (#174)

Don't just remove the first signature node, find all the other signatures
whose digest reference matches too

lib/enveloped-signature.js

@@ -1,13 +1,29 @@
 var xpath = require('xpath');
+var utils = require('./utils');
 
 exports.EnvelopedSignature = EnvelopedSignature;
 
 function EnvelopedSignature() {
 }
 
-EnvelopedSignature.prototype.process = function (node) {
-  var signature = xpath.select("./*[local-name(.)='Signature' and namespace-uri(.)='http://www.w3.org/2000/09/xmldsig#']", node)[0];  
-  if (signature) signature.parentNode.removeChild(signature);
+EnvelopedSignature.prototype.process = function (node, options) {
+  if (null == options.signatureNode) {
+    // leave this for the moment...
+    var signature = xpath.select("./*[local-name(.)='Signature' and namespace-uri(.)='http://www.w3.org/2000/09/xmldsig#']", node)[0];
+    if (signature) signature.parentNode.removeChild(signature);
+    return node;
+  }
+  var signatureNode = options.signatureNode;
+  var expectedSignatureValue = utils.findFirst(signatureNode, ".//*[local-name(.)='SignatureValue']/text()").data;
+  var signatures = xpath.select(".//*[local-name(.)='Signature' and namespace-uri(.)='http://www.w3.org/2000/09/xmldsig#']", node);
+  for (var h in signatures) {
+    if (!signatures.hasOwnProperty(h)) continue;
+    var signature = signatures[h];
+    var signatureValue = utils.findFirst(signature, ".//*[local-name(.)='SignatureValue']/text()").data;
+    if (expectedSignatureValue === signatureValue) {
+      signature.parentNode.removeChild(signature);
+    }
+  }
   return node;
 };
 

lib/signed-xml.js

@@ -815,6 +815,7 @@ SignedXml.prototype.createReferences = function(doc, prefix) {
 SignedXml.prototype.getCanonXml = function(transforms, node, options) {
   options = options || {};
   options.defaultNsForPrefix = options.defaultNsForPrefix || SignedXml.defaultNsForPrefix;
+  options.signatureNode = this.signatureNode;
 
   var canonXml = node.cloneNode(true) // Deep clone