341 lines
12 KiB
Plaintext
341 lines
12 KiB
Plaintext
import {isIP} from 'node:net';
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/**
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* @external URL
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* @see {@link https://developer.mozilla.org/en-US/docs/Web/API/URL|URL}
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*/
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/**
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* @module utils/referrer
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* @private
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*/
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/**
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* @see {@link https://w3c.github.io/webappsec-referrer-policy/#strip-url|Referrer Policy §8.4. Strip url for use as a referrer}
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* @param {string} URL
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* @param {boolean} [originOnly=false]
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*/
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export function stripURLForUseAsAReferrer(url, originOnly = false) {
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// 1. If url is null, return no referrer.
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if (url == null) { // eslint-disable-line no-eq-null, eqeqeq
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return 'no-referrer';
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}
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url = new URL(url);
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// 2. If url's scheme is a local scheme, then return no referrer.
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if (/^(about|blob|data):$/.test(url.protocol)) {
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return 'no-referrer';
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}
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// 3. Set url's username to the empty string.
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url.username = '';
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// 4. Set url's password to null.
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// Note: `null` appears to be a mistake as this actually results in the password being `"null"`.
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url.password = '';
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// 5. Set url's fragment to null.
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// Note: `null` appears to be a mistake as this actually results in the fragment being `"#null"`.
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url.hash = '';
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// 6. If the origin-only flag is true, then:
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if (originOnly) {
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// 6.1. Set url's path to null.
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// Note: `null` appears to be a mistake as this actually results in the path being `"/null"`.
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url.pathname = '';
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// 6.2. Set url's query to null.
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// Note: `null` appears to be a mistake as this actually results in the query being `"?null"`.
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url.search = '';
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}
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// 7. Return url.
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return url;
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}
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/**
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* @see {@link https://w3c.github.io/webappsec-referrer-policy/#enumdef-referrerpolicy|enum ReferrerPolicy}
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*/
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export const ReferrerPolicy = new Set([
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'',
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'no-referrer',
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'no-referrer-when-downgrade',
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'same-origin',
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'origin',
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'strict-origin',
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'origin-when-cross-origin',
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'strict-origin-when-cross-origin',
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'unsafe-url'
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]);
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/**
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* @see {@link https://w3c.github.io/webappsec-referrer-policy/#default-referrer-policy|default referrer policy}
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*/
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export const DEFAULT_REFERRER_POLICY = 'strict-origin-when-cross-origin';
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/**
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* @see {@link https://w3c.github.io/webappsec-referrer-policy/#referrer-policies|Referrer Policy §3. Referrer Policies}
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* @param {string} referrerPolicy
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* @returns {string} referrerPolicy
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*/
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export function validateReferrerPolicy(referrerPolicy) {
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if (!ReferrerPolicy.has(referrerPolicy)) {
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throw new TypeError(`Invalid referrerPolicy: ${referrerPolicy}`);
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}
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return referrerPolicy;
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}
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/**
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* @see {@link https://w3c.github.io/webappsec-secure-contexts/#is-origin-trustworthy|Referrer Policy §3.2. Is origin potentially trustworthy?}
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* @param {external:URL} url
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* @returns `true`: "Potentially Trustworthy", `false`: "Not Trustworthy"
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*/
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export function isOriginPotentiallyTrustworthy(url) {
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// 1. If origin is an opaque origin, return "Not Trustworthy".
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// Not applicable
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// 2. Assert: origin is a tuple origin.
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// Not for implementations
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// 3. If origin's scheme is either "https" or "wss", return "Potentially Trustworthy".
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if (/^(http|ws)s:$/.test(url.protocol)) {
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return true;
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}
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// 4. If origin's host component matches one of the CIDR notations 127.0.0.0/8 or ::1/128 [RFC4632], return "Potentially Trustworthy".
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const hostIp = url.host.replace(/(^\[)|(]$)/g, '');
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const hostIPVersion = isIP(hostIp);
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if (hostIPVersion === 4 && /^127\./.test(hostIp)) {
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return true;
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}
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if (hostIPVersion === 6 && /^(((0+:){7})|(::(0+:){0,6}))0*1$/.test(hostIp)) {
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return true;
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}
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// 5. If origin's host component is "localhost" or falls within ".localhost", and the user agent conforms to the name resolution rules in [let-localhost-be-localhost], return "Potentially Trustworthy".
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// We are returning FALSE here because we cannot ensure conformance to
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// let-localhost-be-loalhost (https://tools.ietf.org/html/draft-west-let-localhost-be-localhost)
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if (url.host === 'localhost' || url.host.endsWith('.localhost')) {
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return false;
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}
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// 6. If origin's scheme component is file, return "Potentially Trustworthy".
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if (url.protocol === 'file:') {
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return true;
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}
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// 7. If origin's scheme component is one which the user agent considers to be authenticated, return "Potentially Trustworthy".
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// Not supported
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// 8. If origin has been configured as a trustworthy origin, return "Potentially Trustworthy".
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// Not supported
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// 9. Return "Not Trustworthy".
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return false;
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}
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/**
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* @see {@link https://w3c.github.io/webappsec-secure-contexts/#is-url-trustworthy|Referrer Policy §3.3. Is url potentially trustworthy?}
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* @param {external:URL} url
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* @returns `true`: "Potentially Trustworthy", `false`: "Not Trustworthy"
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*/
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export function isUrlPotentiallyTrustworthy(url) {
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// 1. If url is "about:blank" or "about:srcdoc", return "Potentially Trustworthy".
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if (/^about:(blank|srcdoc)$/.test(url)) {
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return true;
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}
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// 2. If url's scheme is "data", return "Potentially Trustworthy".
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if (url.protocol === 'data:') {
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return true;
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}
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// Note: The origin of blob: and filesystem: URLs is the origin of the context in which they were
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// created. Therefore, blobs created in a trustworthy origin will themselves be potentially
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// trustworthy.
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if (/^(blob|filesystem):$/.test(url.protocol)) {
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return true;
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}
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// 3. Return the result of executing §3.2 Is origin potentially trustworthy? on url's origin.
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return isOriginPotentiallyTrustworthy(url);
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}
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/**
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* Modifies the referrerURL to enforce any extra security policy considerations.
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* @see {@link https://w3c.github.io/webappsec-referrer-policy/#determine-requests-referrer|Referrer Policy §8.3. Determine request's Referrer}, step 7
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* @callback module:utils/referrer~referrerURLCallback
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* @param {external:URL} referrerURL
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* @returns {external:URL} modified referrerURL
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*/
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/**
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* Modifies the referrerOrigin to enforce any extra security policy considerations.
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* @see {@link https://w3c.github.io/webappsec-referrer-policy/#determine-requests-referrer|Referrer Policy §8.3. Determine request's Referrer}, step 7
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* @callback module:utils/referrer~referrerOriginCallback
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* @param {external:URL} referrerOrigin
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* @returns {external:URL} modified referrerOrigin
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*/
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/**
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* @see {@link https://w3c.github.io/webappsec-referrer-policy/#determine-requests-referrer|Referrer Policy §8.3. Determine request's Referrer}
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* @param {Request} request
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* @param {object} o
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* @param {module:utils/referrer~referrerURLCallback} o.referrerURLCallback
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* @param {module:utils/referrer~referrerOriginCallback} o.referrerOriginCallback
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* @returns {external:URL} Request's referrer
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*/
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export function determineRequestsReferrer(request, {referrerURLCallback, referrerOriginCallback} = {}) {
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// There are 2 notes in the specification about invalid pre-conditions. We return null, here, for
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// these cases:
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// > Note: If request's referrer is "no-referrer", Fetch will not call into this algorithm.
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// > Note: If request's referrer policy is the empty string, Fetch will not call into this
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// > algorithm.
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if (request.referrer === 'no-referrer' || request.referrerPolicy === '') {
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return null;
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}
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// 1. Let policy be request's associated referrer policy.
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const policy = request.referrerPolicy;
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// 2. Let environment be request's client.
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// not applicable to node.js
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// 3. Switch on request's referrer:
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if (request.referrer === 'about:client') {
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return 'no-referrer';
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}
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// "a URL": Let referrerSource be request's referrer.
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const referrerSource = request.referrer;
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// 4. Let request's referrerURL be the result of stripping referrerSource for use as a referrer.
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let referrerURL = stripURLForUseAsAReferrer(referrerSource);
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// 5. Let referrerOrigin be the result of stripping referrerSource for use as a referrer, with the
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// origin-only flag set to true.
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let referrerOrigin = stripURLForUseAsAReferrer(referrerSource, true);
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// 6. If the result of serializing referrerURL is a string whose length is greater than 4096, set
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// referrerURL to referrerOrigin.
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if (referrerURL.toString().length > 4096) {
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referrerURL = referrerOrigin;
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}
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// 7. The user agent MAY alter referrerURL or referrerOrigin at this point to enforce arbitrary
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// policy considerations in the interests of minimizing data leakage. For example, the user
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// agent could strip the URL down to an origin, modify its host, replace it with an empty
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// string, etc.
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if (referrerURLCallback) {
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referrerURL = referrerURLCallback(referrerURL);
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}
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if (referrerOriginCallback) {
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referrerOrigin = referrerOriginCallback(referrerOrigin);
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}
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// 8.Execute the statements corresponding to the value of policy:
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const currentURL = new URL(request.url);
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switch (policy) {
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case 'no-referrer':
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return 'no-referrer';
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case 'origin':
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return referrerOrigin;
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case 'unsafe-url':
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return referrerURL;
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case 'strict-origin':
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// 1. If referrerURL is a potentially trustworthy URL and request's current URL is not a
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// potentially trustworthy URL, then return no referrer.
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if (isUrlPotentiallyTrustworthy(referrerURL) && !isUrlPotentiallyTrustworthy(currentURL)) {
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return 'no-referrer';
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}
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// 2. Return referrerOrigin.
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return referrerOrigin.toString();
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case 'strict-origin-when-cross-origin':
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// 1. If the origin of referrerURL and the origin of request's current URL are the same, then
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// return referrerURL.
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if (referrerURL.origin === currentURL.origin) {
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return referrerURL;
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}
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// 2. If referrerURL is a potentially trustworthy URL and request's current URL is not a
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// potentially trustworthy URL, then return no referrer.
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if (isUrlPotentiallyTrustworthy(referrerURL) && !isUrlPotentiallyTrustworthy(currentURL)) {
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return 'no-referrer';
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}
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// 3. Return referrerOrigin.
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return referrerOrigin;
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case 'same-origin':
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// 1. If the origin of referrerURL and the origin of request's current URL are the same, then
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// return referrerURL.
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if (referrerURL.origin === currentURL.origin) {
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return referrerURL;
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}
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// 2. Return no referrer.
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return 'no-referrer';
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case 'origin-when-cross-origin':
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// 1. If the origin of referrerURL and the origin of request's current URL are the same, then
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// return referrerURL.
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if (referrerURL.origin === currentURL.origin) {
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return referrerURL;
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}
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// Return referrerOrigin.
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return referrerOrigin;
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case 'no-referrer-when-downgrade':
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// 1. If referrerURL is a potentially trustworthy URL and request's current URL is not a
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// potentially trustworthy URL, then return no referrer.
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if (isUrlPotentiallyTrustworthy(referrerURL) && !isUrlPotentiallyTrustworthy(currentURL)) {
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return 'no-referrer';
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}
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// 2. Return referrerURL.
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return referrerURL;
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default:
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throw new TypeError(`Invalid referrerPolicy: ${policy}`);
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}
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}
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/**
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* @see {@link https://w3c.github.io/webappsec-referrer-policy/#parse-referrer-policy-from-header|Referrer Policy §8.1. Parse a referrer policy from a Referrer-Policy header}
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* @param {Headers} headers Response headers
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* @returns {string} policy
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*/
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export function parseReferrerPolicyFromHeader(headers) {
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// 1. Let policy-tokens be the result of extracting header list values given `Referrer-Policy`
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// and response’s header list.
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const policyTokens = (headers.get('referrer-policy') || '').split(/[,\s]+/);
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// 2. Let policy be the empty string.
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let policy = '';
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// 3. For each token in policy-tokens, if token is a referrer policy and token is not the empty
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// string, then set policy to token.
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// Note: This algorithm loops over multiple policy values to allow deployment of new policy
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// values with fallbacks for older user agents, as described in § 11.1 Unknown Policy Values.
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for (const token of policyTokens) {
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if (token && ReferrerPolicy.has(token)) {
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policy = token;
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}
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}
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// 4. Return policy.
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return policy;
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}
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