feat: add PKCE

Author: avdb13

Diff for: src/shared/components/common/modal/create-or-edit-oauth-provider-modal.tsx

@@ -50,6 +50,7 @@ interface ProviderTextFieldProps extends ProviderFieldProps {
 }
 
 type ProviderBooleanProperties =
+  | "use_pkce"
   | "enabled"
   | "account_linking_enabled"
   | "auto_verify_email";
@@ -337,6 +338,18 @@ export default class CreateOrEditOAuthProviderModal extends Component<
                         handleBooleanPropertyChange,
                       )}
                     />
+                    <ProviderCheckboxField
+                      id="use-pkce"
+                      i18nKey="use_pkce"
+                      checked={provider?.use_pkce ?? false}
+                      onInput={linkEvent(
+                        {
+                          modal: this,
+                          property: "use_pkce",
+                        },
+                        handleBooleanPropertyChange,
+                      )}
+                    />
                     <ProviderCheckboxField
                       id="oauth-enabled"
                       i18nKey="oauth_enabled"

Diff for: src/shared/components/home/login.tsx

@@ -25,6 +25,7 @@ import { UnreadCounterService } from "../../services";
 import { RouteData } from "../../interfaces";
 import { IRoutePropsWithFetch } from "../../routes";
 import { simpleScrollMixin } from "../mixins/scroll-mixin";
+import { generatePKCE } from "@utils/helpers/oauth";
 
 interface LoginProps {
   prev?: string;
@@ -126,22 +127,31 @@ export async function handleUseOAuthProvider(params: {
   const redirectUri = `${window.location.origin}/oauth/callback`;
 
   const state = crypto.randomUUID();
+  const [code_challenge, code_verifier] = await generatePKCE();
+
+  const queryPairs = [
+    `client_id=${encodeURIComponent(params.oauth_provider.client_id)}`,
+    `response_type=code`,
+    `scope=${encodeURIComponent(params.oauth_provider.scopes)}`,
+    `redirect_uri=${encodeURIComponent(redirectUri)}`,
+    `state=${state}`,
+    ...(params.oauth_provider.use_pkce
+      ? [
+          `code_challenge=${encodeURIComponent(code_challenge)}`,
+          "code_challenge_method=S256",
+        ]
+      : []),
+  ];
+
   const requestUri =
-    params.oauth_provider.authorization_endpoint +
-    "?" +
-    [
-      `client_id=${encodeURIComponent(params.oauth_provider.client_id)}`,
-      `response_type=code`,
-      `scope=${encodeURIComponent(params.oauth_provider.scopes)}`,
-      `redirect_uri=${encodeURIComponent(redirectUri)}`,
-      `state=${state}`,
-    ].join("&");
+    params.oauth_provider.authorization_endpoint + "?" + queryPairs.join("&");
 
   // store state in local storage
   localStorage.setItem(
     "oauth_state",
     JSON.stringify({
       state,
+      pkce_code_verifier: code_verifier,
       oauth_provider_id: params.oauth_provider.id,
       redirect_uri: redirectUri,
       prev: params.prev ?? "/",

Diff for: src/shared/components/home/oauth/oauth-callback.tsx

@@ -79,6 +79,9 @@ export class OAuthCallback extends Component<OAuthCallbackRouteProps, State> {
         show_nsfw: local_oauth_state.show_nsfw,
         username: local_oauth_state.username,
         answer: local_oauth_state.answer,
+        ...(local_oauth_state?.pkce_code_verifier && {
+          pkce_code_verifier: local_oauth_state.pkce_code_verifier,
+        }),
       });
 
       switch (loginRes.state) {

Diff for: src/shared/components/home/oauth/oauth-provider-list-item.tsx

@@ -86,6 +86,10 @@ export default function OAuthProviderListItem({
               i18nKey="oauth_account_linking_enabled"
               data={boolToYesNo(provider.account_linking_enabled)}
             />
+            <TextInfoField
+              i18nKey="use_pkce"
+              data={boolToYesNo(provider.use_pkce)}
+            />
             <TextInfoField
               i18nKey="oauth_enabled"
               data={boolToYesNo(provider.enabled)}

Diff for: src/shared/components/home/oauth/oauth-providers-tab.tsx

@@ -36,6 +36,7 @@ const PRESET_OAUTH_PROVIDERS: ProviderToEdit[] = [
     scopes: "openid email",
     auto_verify_email: true,
     account_linking_enabled: true,
+    use_pkce: true,
     enabled: true,
   },
   // additional preset providers can be added here

Diff for: src/shared/utils/helpers/oauth.ts

@@ -0,0 +1,44 @@
+const PKCE_VERIFIER_LENGTH = 96;
+
+const PKCE_ALPHABET =
+  "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-._~";
+
+const PKCE_ALGORITHM = "SHA-256";
+
+function urlUnpaddedBase64Encode(value: string): string {
+  return btoa(
+    String.fromCharCode.apply(
+      null,
+      new Uint8Array(new TextEncoder().encode(value)),
+    ),
+  )
+    .replace(/\+/g, "-")
+    .replace(/\//g, "_")
+    .replace(/=+$/, "");
+}
+
+export async function generatePKCE(): Promise<[string, string]> {
+  const randomValues = crypto.getRandomValues(
+    new Uint32Array(PKCE_VERIFIER_LENGTH),
+  );
+
+  const code_verifier = urlUnpaddedBase64Encode(
+    Array.from(randomValues)
+      .map(n => PKCE_ALPHABET[n % PKCE_ALPHABET.length])
+      .join(""),
+  );
+  const code_verifier_digest = await crypto.subtle.digest(
+    PKCE_ALGORITHM,
+    new TextEncoder().encode(code_verifier),
+  );
+  const code_verifier_hash = new Uint8Array(code_verifier_digest);
+
+  let code_challenge = "";
+  for (let i = 0; i < code_verifier_hash.byteLength; i++) {
+    code_challenge = code_challenge.concat(
+      String.fromCharCode(code_verifier_hash[i]),
+    );
+  }
+
+  return [urlUnpaddedBase64Encode(code_challenge), code_verifier];
+}