Enable PKCE by default for Keycloak JS (#26412)

Closes #26411

Signed-off-by: Jon Koops <jonkoops@gmail.com>

docs/documentation/release_notes/topics/24_0_0.adoc

@@ -6,9 +6,15 @@ image::images/new-welcome-screen.png["A screenshot of the new welcome page, show
 
 If you are using a custom theme, you may need to update it to support the new welcome page. For more details consult the link:{upgradingguide_link}[{upgradingguide_name}].
 
-= Keycloak JS using `exports` field
+= Keycloak JS
 
-The Keycloak JS adapter now uses the https://webpack.js.org/guides/package-exports/[`exports` field] in `package.json`. This change improves support for more modern bundlers like Webpack 5 and Vite, but comes with some unavoidable breaking changes. Consult the link:{upgradingguide_link}[{upgradingguide_name}] for more details.
+== Using `exports` field in `package.json`
+
+The Keycloak JS adapter now uses the https://webpack.js.org/guides/package-exports/[`exports` field] in its `package.json`. This change improves support for more modern bundlers like Webpack 5 and Vite, but comes with some unavoidable breaking changes. Consult the link:{upgradingguide_link}[{upgradingguide_name}] for more details.
+
+== PKCE enabled by default
+
+The Keycloak JS adapter now sets the `pkceMethod` option to `S256` by default. This enables Proof Key Code Exchange (https://datatracker.ietf.org/doc/html/rfc7636[PKCE]) for all applications using the adapter. If you are using the adapter on a system that doesn't support PKCE, you can set the `pkceMethod` option to `false` to disable it.
 
 = Truststore Improvements
 

docs/documentation/securing_apps/topics/oidc/javascript-adapter.adoc

@@ -369,7 +369,8 @@ to {project_name} will contain the scope parameter `scope=openid address phone`.
 * flow - Set the OpenID Connect flow. Valid values are `standard`, `implicit` or `hybrid`.
 * enableLogging - Enables logging messages from Keycloak to the console (default is `false`).
 * pkceMethod - The method for Proof Key Code Exchange (https://datatracker.ietf.org/doc/html/rfc7636[PKCE]) to use. Configuring this value enables the PKCE mechanism. Available options:
-    - "S256" - The SHA256 based PKCE method
+    - "S256" - The SHA256 based PKCE method (default)
+    - false - PKCE is disabled.
 * acrValues - Generates the `acr_values` parameter which refers to authentication context class reference and allows clients to declare the required assurance level requirements, e.g. authentication mechanisms. See https://openid.net/specs/openid-connect-modrna-authentication-1_0.html#acr_values[Section 4. acr_values request values and level of assurance in OpenID Connect MODRNA Authentication Profile 1.0].
 * messageReceiveTimeout - Set a timeout in milliseconds for waiting for message responses from the Keycloak server. This is used, for example, when waiting for a message during 3rd party cookies check. The default value is 10000.
 * locale - When onLoad is 'login-required', sets the 'ui_locales' query param in compliance with https://openid.net/specs/openid-connect-core-1_0.html#AuthRequest[section 3.1.2.1 of the OIDC 1.0 specification].

js/apps/account-ui/src/main.tsx

@@ -13,7 +13,6 @@ import { routes } from "./routes";
 await Promise.all([
   keycloak.init({
     onLoad: "check-sso",
-    pkceMethod: "S256",
   }),
   i18n.init(),
 ]);

js/apps/admin-ui/src/keycloak.ts

@@ -11,7 +11,6 @@ export const keycloak = new Keycloak({
 export async function initKeycloak() {
   const authenticated = await keycloak.init({
     onLoad: "check-sso",
-    pkceMethod: "S256",
   });
 
   // Force the user to login if not authenticated.

js/libs/keycloak-js/dist/keycloak.d.ts

@@ -22,7 +22,7 @@ export type KeycloakOnLoad = 'login-required'|'check-sso';
 export type KeycloakResponseMode = 'query'|'fragment';
 export type KeycloakResponseType = 'code'|'id_token token'|'code id_token token';
 export type KeycloakFlow = 'standard'|'implicit'|'hybrid';
-export type KeycloakPkceMethod = 'S256';
+export type KeycloakPkceMethod = 'S256' | false;
 
 export interface KeycloakConfig {
 	/**
@@ -169,9 +169,8 @@ export interface KeycloakInitOptions {
 	flow?: KeycloakFlow;
 
 	/**
-	 * Configures the Proof Key for Code Exchange (PKCE) method to use.
+	 * Configures the Proof Key for Code Exchange (PKCE) method to use. This will default to 'S256'.
-	 * The currently allowed method is 'S256'.
+	 * Can be disabled by passing `false`.
-	 * If not configured, PKCE will not be used.
 	 */
 	pkceMethod?: KeycloakPkceMethod;
 

js/libs/keycloak-js/src/keycloak.js

@@ -134,9 +134,11 @@ function Keycloak (config) {
 
             if (initOptions.pkceMethod) {
                 if (initOptions.pkceMethod !== "S256") {
-                    throw 'Invalid value for pkceMethod';
+                    throw new TypeError(`Invalid value for 'pkceMethod', expected 'S256' but got '${initOptions.pkceMethod}'.`);
                 }
                 kc.pkceMethod = initOptions.pkceMethod;
+            } else {
+                kc.pkceMethod = "S256";
             }
 
             if (typeof initOptions.enableLogging === 'boolean') {
@@ -374,19 +376,18 @@ function Keycloak (config) {
     }
 
     function generatePkceChallenge(pkceMethod, codeVerifier) {
-        switch (pkceMethod) {
+        if (pkceMethod !== "S256") {
-            // The use of the "plain" method is considered insecure and therefore not supported.
+            throw new TypeError(`Invalid value for 'pkceMethod', expected 'S256' but got '${pkceMethod}'.`);
-            case "S256":
+        }
+
         // hash codeVerifier, then encode as url-safe base64 without padding
-                var hashBytes = new Uint8Array(sha256.arrayBuffer(codeVerifier));
+        const hashBytes = new Uint8Array(sha256.arrayBuffer(codeVerifier));
-                var encodedHash = bytesToBase64(hashBytes)
+        const encodedHash = bytesToBase64(hashBytes)
             .replace(/\+/g, '-')
             .replace(/\//g, '_')
             .replace(/\=/g, '');
+
         return encodedHash;
-            default:
-                throw 'Invalid value for pkceMethod';
-        }
     }
 
     function buildClaimsParameter(requestedAcr){

themes/src/main/resources/theme/keycloak.v2/account/index.ftl

@@ -127,7 +127,7 @@
                 realm: realm,
                 clientId: 'account-console'
             });
-            keycloak.init({onLoad: 'check-sso', pkceMethod: 'S256', promiseType: 'native'}).then((authenticated) => {
+            keycloak.init({onLoad: 'check-sso'}).then((authenticated) => {
                 isReactLoading = true;
                 toggleReact();
                 if (!keycloak.authenticated) {