dummyAnchor href check

Author: archmoj

src/lib/svg_text_utils.js

@@ -604,14 +604,9 @@ function buildSVGText(containerNode, str) {
                     var href = getQuotedMatch(extra, HREFMATCH);
 
                     if(href) {
-                        // check safe protocols
-                        var dummyAnchor = document.createElement('a');
-                        dummyAnchor.href = href;
-                        if(PROTOCOLS.indexOf(dummyAnchor.protocol) !== -1) {
-                            // Decode href to allow both already encoded and not encoded
-                            // URIs. Without decoding prior encoding, an already encoded
-                            // URI would be encoded twice producing a semantically different URI.
-                            nodeSpec.href = encodeURI(decodeURI(href));
+                        var safeHref = sanitizeHref(href);
+                        if(safeHref) {
+                            nodeSpec.href = safeHref;
                             nodeSpec.target = getQuotedMatch(extra, TARGETMATCH) || '_blank';
                             nodeSpec.popup = getQuotedMatch(extra, POPUPMATCH);
                         }
@@ -626,6 +621,27 @@ function buildSVGText(containerNode, str) {
     return hasLink;
 }
 
+function sanitizeHref(href) {
+    var decodedHref = encodeURI(decodeURI(href));
+    var dummyAnchor1 = document.createElement('a');
+    var dummyAnchor2 = document.createElement('a');
+    dummyAnchor1.href = href;
+    dummyAnchor2.href = decodedHref;
+
+    var p1 = dummyAnchor1.protocol;
+    var p2 = dummyAnchor2.protocol;
+
+    // check safe protocols
+    if(
+        PROTOCOLS.indexOf(p1) !== -1 &&
+        PROTOCOLS.indexOf(p2) !== -1
+    ) {
+        return decodedHref;
+    } else {
+        return '';
+    }
+}
+
 /*
  * sanitizeHTML: port of buildSVGText aimed at providing a clean subset of HTML
  * @param {string} str: the html string to clean
@@ -660,10 +676,9 @@ exports.sanitizeHTML = function sanitizeHTML(str) {
                     var href = getQuotedMatch(extra, HREFMATCH);
 
                     if(href) {
-                        var dummyAnchor = document.createElement('a');
-                        dummyAnchor.href = href;
-                        if(PROTOCOLS.indexOf(dummyAnchor.protocol) !== -1) {
-                            nodeAttrs.href = encodeURI(decodeURI(href));
+                        var safeHref = sanitizeHref(href);
+                        if(safeHref) {
+                            nodeAttrs.href = safeHref;
                             var target = getQuotedMatch(extra, TARGETMATCH);
                             if(target) {
                                 nodeAttrs.target = target;

test/jasmine/tests/svg_text_utils_test.js

@@ -85,6 +85,16 @@ describe('svg+text utils', function() {
             d3.selectAll('.text-tester').remove();
         });
 
+        it('checks for XSS attack in href protocol', function() {
+            var node = mockTextSVGElement(
+                '<a href="j%61vascript:alert(\'attack\')">XSS</a>'
+            );
+
+            expect(node.text()).toEqual('XSS');
+            assertAnchorAttrs(node);
+            assertAnchorLink(node, null);
+        });
+
         it('checks for XSS attack in href', function() {
             var node = mockTextSVGElement(
                 '<a href="javascript:alert(\'attack\')">XSS</a>'
@@ -534,6 +544,14 @@ describe('sanitizeHTML', function() {
         d3.selectAll('.text-tester').remove();
     });
 
+    it('checks for XSS attack in href protocol', function() {
+        var innerHTML = mockHTML(
+            '<a href="j%61vascript:alert(\'attack\')">XSS</a>'
+        );
+
+        expect(innerHTML).toEqual('<a>XSS</a>');
+    });
+
     it('checks for XSS attack in href', function() {
         var innerHTML = mockHTML(
             '<a href="javascript:alert(\'attack\')">XSS</a>'