'use strict';

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 *     Any commits to this file should be reviewed with security in mind.  *
 *   Changes to this file can potentially create security vulnerabilities. *
 *          An approval from 2 Core members with history of modifying      *
 *                         this file is required.                          *
 *                                                                         *
 *  Does the change somehow allow for arbitrary javascript to be executed? *
 *    Or allows for someone to change the prototype of built-in objects?   *
 *     Or gives undesired access to variables likes document or window?    *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

var $sanitizeMinErr = angular.$$minErr('$sanitize');

/**
 * @ngdoc module
 * @name ngSanitize
 * @description
 *
 * # ngSanitize
 *
 * The `ngSanitize` module provides functionality to sanitize HTML.
 *
 *
 * <div doc-module-components="ngSanitize"></div>
 *
 * See {@link ngSanitize.$sanitize `$sanitize`} for usage.
 */

/**
 * @ngdoc service
 * @name $sanitize
 * @kind function
 *
 * @description
 *   Sanitizes an html string by stripping all potentially dangerous tokens.
 *
 *   The input is sanitized by parsing the HTML into tokens. All safe tokens (from a whitelist) are
 *   then serialized back to properly escaped html string. This means that no unsafe input can make
 *   it into the returned string.
 *
 *   The whitelist for URL sanitization of attribute values is configured using the functions
 *   `aHrefSanitizationWhitelist` and `imgSrcSanitizationWhitelist` of {@link ng.$compileProvider
 *   `$compileProvider`}.
 *
 *   The input may also contain SVG markup if this is enabled via {@link $sanitizeProvider}.
 *
 * @param {string} html HTML input.
 * @returns {string} Sanitized HTML.
 *
 * @example
   <example module="sanitizeExample" deps="angular-sanitize.js">
   <file name="index.html">
     <script>
         angular.module('sanitizeExample', ['ngSanitize'])
           .controller('ExampleController', ['$scope', '$sce', function($scope, $sce) {
             $scope.snippet =
               '<p style="color:blue">an html\n' +
               '<em onmouseover="this.textContent=\'PWN3D!\'">click here</em>\n' +
               'snippet</p>';
             $scope.deliberatelyTrustDangerousSnippet = function() {
               return $sce.trustAsHtml($scope.snippet);
             };
           }]);
     </script>
     <div ng-controller="ExampleController">
        Snippet: <textarea ng-model="snippet" cols="60" rows="3"></textarea>
       <table>
         <tr>
           <td>Directive</td>
           <td>How</td>
           <td>Source</td>
           <td>Rendered</td>
         </tr>
         <tr id="bind-html-with-sanitize">
           <td>ng-bind-html</td>
           <td>Automatically uses $sanitize</td>
           <td><pre>&lt;div ng-bind-html="snippet"&gt;<br/>&lt;/div&gt;</pre></td>
           <td><div ng-bind-html="snippet"></div></td>
         </tr>
         <tr id="bind-html-with-trust">
           <td>ng-bind-html</td>
           <td>Bypass $sanitize by explicitly trusting the dangerous value</td>
           <td>
           <pre>&lt;div ng-bind-html="deliberatelyTrustDangerousSnippet()"&gt;
&lt;/div&gt;</pre>
           </td>
           <td><div ng-bind-html="deliberatelyTrustDangerousSnippet()"></div></td>
         </tr>
         <tr id="bind-default">
           <td>ng-bind</td>
           <td>Automatically escapes</td>
           <td><pre>&lt;div ng-bind="snippet"&gt;<br/>&lt;/div&gt;</pre></td>
           <td><div ng-bind="snippet"></div></td>
         </tr>
       </table>
       </div>
   </file>
   <file name="protractor.js" type="protractor">
     it('should sanitize the html snippet by default', function() {
       expect(element(by.css('#bind-html-with-sanitize div')).getInnerHtml()).
         toBe('<p>an html\n<em>click here</em>\nsnippet</p>');
     });

     it('should inline raw snippet if bound to a trusted value', function() {
       expect(element(by.css('#bind-html-with-trust div')).getInnerHtml()).
         toBe("<p style=\"color:blue\">an html\n" +
              "<em onmouseover=\"this.textContent='PWN3D!'\">click here</em>\n" +
              "snippet</p>");
     });

     it('should escape snippet without any filter', function() {
       expect(element(by.css('#bind-default div')).getInnerHtml()).
         toBe("&lt;p style=\"color:blue\"&gt;an html\n" +
              "&lt;em onmouseover=\"this.textContent='PWN3D!'\"&gt;click here&lt;/em&gt;\n" +
              "snippet&lt;/p&gt;");
     });

     it('should update', function() {
       element(by.model('snippet')).clear();
       element(by.model('snippet')).sendKeys('new <b onclick="alert(1)">text</b>');
       expect(element(by.css('#bind-html-with-sanitize div')).getInnerHtml()).
         toBe('new <b>text</b>');
       expect(element(by.css('#bind-html-with-trust div')).getInnerHtml()).toBe(
         'new <b onclick="alert(1)">text</b>');
       expect(element(by.css('#bind-default div')).getInnerHtml()).toBe(
         "new &lt;b onclick=\"alert(1)\"&gt;text&lt;/b&gt;");
     });
   </file>
   </example>
 */


/**
 * @ngdoc provider
 * @name $sanitizeProvider
 *
 * @description
 * Creates and configures {@link $sanitize} instance.
 */
function $SanitizeProvider() {
  var svgEnabled = false;

  this.$get = ['$$sanitizeUri', function($$sanitizeUri) {
    if (svgEnabled) {
      angular.extend(validElements, svgElements);
    }
    return function(html) {
      var buf = [];
      htmlParser(html, htmlSanitizeWriter(buf, function(uri, isImage) {
        return !/^unsafe:/.test($$sanitizeUri(uri, isImage));
      }));
      return buf.join('');
    };
  }];


  /**
   * @ngdoc method
   * @name $sanitizeProvider#enableSvg
   * @kind function
   *
   * @description
   * Enables a subset of svg to be supported by the sanitizer.
   *
   * <div class="alert alert-warning">
   *   <p>By enabling this setting without taking other precautions, you might expose your
   *   application to click-hijacking attacks. In these attacks, sanitized svg elements could be positioned
   *   outside of the containing element and be rendered over other elements on the page (e.g. a login
   *   link). Such behavior can then result in phishing incidents.</p>
   *
   *   <p>To protect against these, explicitly setup `overflow: hidden` css rule for all potential svg
   *   tags within the sanitized content:</p>
   *
   *   <br>
   *
   *   <pre><code>
   *   .rootOfTheIncludedContent svg {
   *     overflow: hidden !important;
   *   }
   *   </code></pre>
   * </div>
   *
   * @param {boolean=} regexp New regexp to whitelist urls with.
   * @returns {boolean|ng.$sanitizeProvider} Returns the currently configured value if called
   *    without an argument or self for chaining otherwise.
   */
  this.enableSvg = function(enableSvg) {
    if (angular.isDefined(enableSvg)) {
      svgEnabled = enableSvg;
      return this;
    } else {
      return svgEnabled;
    }
  };
}

function sanitizeText(chars) {
  var buf = [];
  var writer = htmlSanitizeWriter(buf, angular.noop);
  writer.chars(chars);
  return buf.join('');
}


// Regular Expressions for parsing tags and attributes
var SURROGATE_PAIR_REGEXP = /[\uD800-\uDBFF][\uDC00-\uDFFF]/g,
  // Match everything outside of normal chars and " (quote character)
  NON_ALPHANUMERIC_REGEXP = /([^\#-~ |!])/g;


// Good source of info about elements and attributes
// http://dev.w3.org/html5/spec/Overview.html#semantics
// http://simon.html5.org/html-elements

// Safe Void Elements - HTML5
// http://dev.w3.org/html5/spec/Overview.html#void-elements
var voidElements = toMap("area,br,col,hr,img,wbr");

// Elements that you can, intentionally, leave open (and which close themselves)
// http://dev.w3.org/html5/spec/Overview.html#optional-tags
var optionalEndTagBlockElements = toMap("colgroup,dd,dt,li,p,tbody,td,tfoot,th,thead,tr"),
    optionalEndTagInlineElements = toMap("rp,rt"),
    optionalEndTagElements = angular.extend({},
                                            optionalEndTagInlineElements,
                                            optionalEndTagBlockElements);

// Safe Block Elements - HTML5
var blockElements = angular.extend({}, optionalEndTagBlockElements, toMap("address,article," +
        "aside,blockquote,caption,center,del,dir,div,dl,figure,figcaption,footer,h1,h2,h3,h4,h5," +
        "h6,header,hgroup,hr,ins,map,menu,nav,ol,pre,section,table,ul"));

// Inline Elements - HTML5
var inlineElements = angular.extend({}, optionalEndTagInlineElements, toMap("a,abbr,acronym,b," +
        "bdi,bdo,big,br,cite,code,del,dfn,em,font,i,img,ins,kbd,label,map,mark,q,ruby,rp,rt,s," +
        "samp,small,span,strike,strong,sub,sup,time,tt,u,var"));

// SVG Elements
// https://wiki.whatwg.org/wiki/Sanitization_rules#svg_Elements
// Note: the elements animate,animateColor,animateMotion,animateTransform,set are intentionally omitted.
// They can potentially allow for arbitrary javascript to be executed. See #11290
var svgElements = toMap("circle,defs,desc,ellipse,font-face,font-face-name,font-face-src,g,glyph," +
        "hkern,image,linearGradient,line,marker,metadata,missing-glyph,mpath,path,polygon,polyline," +
        "radialGradient,rect,stop,svg,switch,text,title,tspan,use");

// Blocked Elements (will be stripped)
var blockedElements = toMap("script,style");

var validElements = angular.extend({},
                                   voidElements,
                                   blockElements,
                                   inlineElements,
                                   optionalEndTagElements);

//Attributes that have href and hence need to be sanitized
var uriAttrs = toMap("background,cite,href,longdesc,src,usemap,xlink:href");

var htmlAttrs = toMap('abbr,align,alt,axis,bgcolor,border,cellpadding,cellspacing,class,clear,' +
    'color,cols,colspan,compact,coords,dir,face,headers,height,hreflang,hspace,' +
    'ismap,lang,language,nohref,nowrap,rel,rev,rows,rowspan,rules,' +
    'scope,scrolling,shape,size,span,start,summary,tabindex,target,title,type,' +
    'valign,value,vspace,width');

// SVG attributes (without "id" and "name" attributes)
// https://wiki.whatwg.org/wiki/Sanitization_rules#svg_Attributes
var svgAttrs = toMap('accent-height,accumulate,additive,alphabetic,arabic-form,ascent,' +
    'baseProfile,bbox,begin,by,calcMode,cap-height,class,color,color-rendering,content,' +
    'cx,cy,d,dx,dy,descent,display,dur,end,fill,fill-rule,font-family,font-size,font-stretch,' +
    'font-style,font-variant,font-weight,from,fx,fy,g1,g2,glyph-name,gradientUnits,hanging,' +
    'height,horiz-adv-x,horiz-origin-x,ideographic,k,keyPoints,keySplines,keyTimes,lang,' +
    'marker-end,marker-mid,marker-start,markerHeight,markerUnits,markerWidth,mathematical,' +
    'max,min,offset,opacity,orient,origin,overline-position,overline-thickness,panose-1,' +
    'path,pathLength,points,preserveAspectRatio,r,refX,refY,repeatCount,repeatDur,' +
    'requiredExtensions,requiredFeatures,restart,rotate,rx,ry,slope,stemh,stemv,stop-color,' +
    'stop-opacity,strikethrough-position,strikethrough-thickness,stroke,stroke-dasharray,' +
    'stroke-dashoffset,stroke-linecap,stroke-linejoin,stroke-miterlimit,stroke-opacity,' +
    'stroke-width,systemLanguage,target,text-anchor,to,transform,type,u1,u2,underline-position,' +
    'underline-thickness,unicode,unicode-range,units-per-em,values,version,viewBox,visibility,' +
    'width,widths,x,x-height,x1,x2,xlink:actuate,xlink:arcrole,xlink:role,xlink:show,xlink:title,' +
    'xlink:type,xml:base,xml:lang,xml:space,xmlns,xmlns:xlink,y,y1,y2,zoomAndPan', true);

var validAttrs = angular.extend({},
                                uriAttrs,
                                svgAttrs,
                                htmlAttrs);

function toMap(str, lowercaseKeys) {
  var obj = {}, items = str.split(','), i;
  for (i = 0; i < items.length; i++) {
    obj[lowercaseKeys ? angular.lowercase(items[i]) : items[i]] = true;
  }
  return obj;
}

var inertBodyElement;
(function(window) {
  var doc;
  if (window.document && window.document.implementation) {
    doc = window.document.implementation.createHTMLDocument("inert");
  } else {
    throw $sanitizeMinErr('noinert', "Can't create an inert html document");
  }
  var docElement = doc.documentElement || doc.getDocumentElement();
  var bodyElements = docElement.getElementsByTagName('body');

  // usually there should be only one body element in the document, but IE doesn't have any, so we need to create one
  if (bodyElements.length === 1) {
    inertBodyElement = bodyElements[0];
  } else {
    var html = doc.createElement('html');
    inertBodyElement = doc.createElement('body');
    html.appendChild(inertBodyElement);
    doc.appendChild(html);
  }
})(window);

/**
 * @example
 * htmlParser(htmlString, {
 *     start: function(tag, attrs) {},
 *     end: function(tag) {},
 *     chars: function(text) {},
 *     comment: function(text) {}
 * });
 *
 * @param {string} html string
 * @param {object} handler
 */
function htmlParser(html, handler) {
  if (html === null || html === undefined) {
    html = '';
  } else if (typeof html !== 'string') {
    html = '' + html;
  }
  inertBodyElement.innerHTML = html;

  //mXSS protection
  var mXSSAttempts = 5;
  do {
    if (mXSSAttempts === 0) {
      throw $sanitizeMinErr('uinput', "Failed to sanitize html because the input is unstable");
    }
    mXSSAttempts--;

    // strip custom-namespaced attributes on IE<=11
    if (document.documentMode <= 11) {
      stripCustomNsAttrs(inertBodyElement);
    }
    html = inertBodyElement.innerHTML; //trigger mXSS
    inertBodyElement.innerHTML = html;
  } while (html !== inertBodyElement.innerHTML);

  var node = inertBodyElement.firstChild;
  while (node) {
    switch (node.nodeType) {
      case 1: // ELEMENT_NODE
        handler.start(node.nodeName.toLowerCase(), attrToMap(node.attributes));
        break;
      case 3: // TEXT NODE
        handler.chars(node.textContent);
        break;
    }

    var nextNode;
    if (!(nextNode = node.firstChild)) {
      if (node.nodeType == 1) {
        handler.end(node.nodeName.toLowerCase());
      }
      nextNode = node.nextSibling;
      if (!nextNode) {
        while (nextNode == null) {
          node = node.parentNode;
          if (node === inertBodyElement) break;
          nextNode = node.nextSibling;
          if (node.nodeType == 1) {
            handler.end(node.nodeName.toLowerCase());
          }
        }
      }
    }
    node = nextNode;
  }

  while (node = inertBodyElement.firstChild) {
    inertBodyElement.removeChild(node);
  }
}

function attrToMap(attrs) {
  var map = {};
  for (var i = 0, ii = attrs.length; i < ii; i++) {
    var attr = attrs[i];
    map[attr.name] = attr.value;
  }
  return map;
}


/**
 * Escapes all potentially dangerous characters, so that the
 * resulting string can be safely inserted into attribute or
 * element text.
 * @param value
 * @returns {string} escaped text
 */
function encodeEntities(value) {
  return value.
    replace(/&/g, '&amp;').
    replace(SURROGATE_PAIR_REGEXP, function(value) {
      var hi = value.charCodeAt(0);
      var low = value.charCodeAt(1);
      return '&#' + (((hi - 0xD800) * 0x400) + (low - 0xDC00) + 0x10000) + ';';
    }).
    replace(NON_ALPHANUMERIC_REGEXP, function(value) {
      return '&#' + value.charCodeAt(0) + ';';
    }).
    replace(/</g, '&lt;').
    replace(/>/g, '&gt;');
}

/**
 * create an HTML/XML writer which writes to buffer
 * @param {Array} buf use buf.join('') to get out sanitized html string
 * @returns {object} in the form of {
 *     start: function(tag, attrs) {},
 *     end: function(tag) {},
 *     chars: function(text) {},
 *     comment: function(text) {}
 * }
 */
function htmlSanitizeWriter(buf, uriValidator) {
  var ignoreCurrentElement = false;
  var out = angular.bind(buf, buf.push);
  return {
    start: function(tag, attrs) {
      tag = angular.lowercase(tag);
      if (!ignoreCurrentElement && blockedElements[tag]) {
        ignoreCurrentElement = tag;
      }
      if (!ignoreCurrentElement && validElements[tag] === true) {
        out('<');
        out(tag);
        angular.forEach(attrs, function(value, key) {
          var lkey=angular.lowercase(key);
          var isImage = (tag === 'img' && lkey === 'src') || (lkey === 'background');
          if (validAttrs[lkey] === true &&
            (uriAttrs[lkey] !== true || uriValidator(value, isImage))) {
            out(' ');
            out(key);
            out('="');
            out(encodeEntities(value));
            out('"');
          }
        });
        out('>');
      }
    },
    end: function(tag) {
      tag = angular.lowercase(tag);
      if (!ignoreCurrentElement && validElements[tag] === true && voidElements[tag] !== true) {
        out('</');
        out(tag);
        out('>');
      }
      if (tag == ignoreCurrentElement) {
        ignoreCurrentElement = false;
      }
    },
    chars: function(chars) {
      if (!ignoreCurrentElement) {
        out(encodeEntities(chars));
      }
    }
  };
}


/**
 * When IE9-11 comes across an unknown namespaced attribute e.g. 'xlink:foo' it adds 'xmlns:ns1' attribute to declare
 * ns1 namespace and prefixes the attribute with 'ns1' (e.g. 'ns1:xlink:foo'). This is undesirable since we don't want
 * to allow any of these custom attributes. This method strips them all.
 *
 * @param node Root element to process
 */
function stripCustomNsAttrs(node) {
  if (node.nodeType === Node.ELEMENT_NODE) {
    var attrs = node.attributes;
    for (var i = 0, l = attrs.length; i < l; i++) {
      var attrNode = attrs[i];
      var attrName = attrNode.name.toLowerCase();
      if (attrName === 'xmlns:ns1' || attrName.indexOf('ns1:') === 0) {
        node.removeAttributeNode(attrNode);
        i--;
        l--;
      }
    }
  }

  var nextNode = node.firstChild;
  if (nextNode) {
    stripCustomNsAttrs(nextNode);
  }

  nextNode = node.nextSibling;
  if (nextNode) {
    stripCustomNsAttrs(nextNode);
  }
}



// define ngSanitize module and register $sanitize service
angular.module('ngSanitize', []).provider('$sanitize', $SanitizeProvider);