fix: oauth state is encrypted

src/lib/oauth/providerUtil.ts

@@ -11,7 +11,7 @@ export function findProvider(
 export const githubAuth = {
   url: (clientId: string, state?: string, redirectUri?: string) =>
     `https://github.com/login/oauth/authorize?client_id=${clientId}&scope=read:user${
-      state ? `&state=${state}` : ''
+      state ? `&state=${encodeURIComponent(state)}` : ''
     }${redirectUri ? `&redirect_uri=${encodeURIComponent(redirectUri)}` : ''}`,
   user: async (accessToken: string) => {
     const res = await fetch('https://api.github.com/user', {
@@ -29,7 +29,7 @@ export const discordAuth = {
   url: (clientId: string, origin: string, state?: string, redirectUri?: string) =>
     `https://discord.com/api/oauth2/authorize?client_id=${clientId}&redirect_uri=${encodeURIComponent(
       redirectUri ?? `${origin}/api/auth/oauth/discord`,
-    )}&response_type=code&scope=identify${state ? `&state=${state}` : ''}`,
+    )}&response_type=code&scope=identify${state ? `&state=${encodeURIComponent(state)}` : ''}`,
   user: async (accessToken: string) => {
     const res = await fetch('https://discord.com/api/users/@me', {
       headers: {
@@ -47,7 +47,7 @@ export const googleAuth = {
     `https://accounts.google.com/o/oauth2/auth?client_id=${clientId}&redirect_uri=${encodeURIComponent(
       redirectUri ?? `${origin}/api/auth/oauth/google`,
     )}&response_type=code&access_type=offline&scope=https://www.googleapis.com/auth/userinfo.profile${
-      state ? `&state=${state}` : ''
+      state ? `&state=${encodeURIComponent(state)}` : ''
     }`,
   user: async (accessToken: string) => {
     const res = await fetch('https://www.googleapis.com/oauth2/v1/userinfo?alt=json', {
@@ -65,7 +65,7 @@ export const oidcAuth = {
   url: (clientId: string, origin: string, authorizeUrl: string, state?: string, redirectUri?: string) =>
     `${authorizeUrl}?client_id=${clientId}&redirect_uri=${encodeURIComponent(
       redirectUri ?? `${origin}/api/auth/oauth/oidc`,
-    )}&response_type=code&scope=openid+email+profile+offline_access${state ? `&state=${state}` : ''}`,
+    )}&response_type=code&scope=openid+email+profile+offline_access${state ? `&state=${encodeURIComponent(state)}` : ''}`,
   user: async (accessToken: string, userInfoUrl: string) => {
     const res = await fetch(userInfoUrl, {
       headers: {

src/lib/oauth/withOAuth.ts

@@ -2,7 +2,7 @@ import { NextApiReq, NextApiRes } from '@/lib/response';
 import { OAuthProviderType } from '@prisma/client';
 import { prisma } from '../db';
 import { findProvider } from './providerUtil';
-import { createToken } from '../crypto';
+import { createToken, decrypt } from '../crypto';
 import { config } from '../config';
 import { User } from '../db/models/user';
 import Logger, { log } from '../logger';
@@ -88,7 +88,14 @@ export const withOAuth =
 
     const userOauth = findProvider(provider, user?.oauthProviders ?? []);
 
-    if (state === 'link') {
+    let urlState;
+    try {
+      urlState = decrypt(decodeURIComponent(state ?? ''), config.core.secret);
+    } catch {
+      urlState = null;
+    }
+
+    if (urlState === 'link') {
       if (!user) return res.unauthorized('invalid session');
 
       if (findProvider(provider, user.oauthProviders))

src/pages/api/auth/oauth/discord.ts

@@ -6,8 +6,9 @@ import enabled from '@/lib/oauth/enabled';
 import { discordAuth } from '@/lib/oauth/providerUtil';
 import { fetchToDataURL } from '@/lib/base64';
 import Logger from '@/lib/logger';
+import { encrypt } from '@/lib/crypto';
 
-async function handler({ code, state, host }: OAuthQuery, logger: Logger): Promise<OAuthResponse> {
+async function handler({ code, host }: OAuthQuery, logger: Logger): Promise<OAuthResponse> {
   if (!config.features.oauthRegistration)
     return {
       error: 'OAuth registration is disabled.',
@@ -22,15 +23,18 @@ async function handler({ code, state, host }: OAuthQuery, logger: Logger): Promi
       error_code: 401,
     };
 
-  if (!code)
+  if (!code) {
+    const linkState = encrypt('link', config.core.secret);
+
     return {
       redirect: discordAuth.url(
         config.oauth.discord.clientId!,
         `${config.core.returnHttpsUrls ? 'https' : 'http'}://${host}`,
-        state,
+        linkState,
         config.oauth.discord.redirectUri ?? undefined,
       ),
     };
+  }
 
   const body = new URLSearchParams({
     client_id: config.oauth.discord.clientId!,

src/pages/api/auth/oauth/github.ts

@@ -1,13 +1,14 @@
 import { fetchToDataURL } from '@/lib/base64';
 import { config } from '@/lib/config';
+import { encrypt } from '@/lib/crypto';
 import Logger from '@/lib/logger';
 import { combine } from '@/lib/middleware/combine';
 import { method } from '@/lib/middleware/method';
 import enabled from '@/lib/oauth/enabled';
 import { githubAuth } from '@/lib/oauth/providerUtil';
 import { OAuthQuery, OAuthResponse, withOAuth } from '@/lib/oauth/withOAuth';
 
-async function handler({ code, state }: OAuthQuery, logger: Logger): Promise<OAuthResponse> {
+async function handler({ code }: OAuthQuery, logger: Logger): Promise<OAuthResponse> {
   if (!config.features.oauthRegistration)
     return {
       error: 'OAuth registration is disabled.',
@@ -22,14 +23,17 @@ async function handler({ code, state }: OAuthQuery, logger: Logger): Promise<OAu
       error_code: 401,
     };
 
-  if (!code)
+  if (!code) {
+    const linkState = encrypt('link', config.core.secret);
+
     return {
       redirect: githubAuth.url(
         config.oauth.github.clientId!,
-        state,
+        linkState,
         config.oauth.github.redirectUri ?? undefined,
       ),
     };
+  }
 
   const body = JSON.stringify({
     client_id: config.oauth.github.clientId!,

src/pages/api/auth/oauth/google.ts

@@ -1,13 +1,14 @@
 import { fetchToDataURL } from '@/lib/base64';
 import { config } from '@/lib/config';
+import { encrypt } from '@/lib/crypto';
 import Logger from '@/lib/logger';
 import { combine } from '@/lib/middleware/combine';
 import { method } from '@/lib/middleware/method';
 import enabled from '@/lib/oauth/enabled';
 import { googleAuth } from '@/lib/oauth/providerUtil';
 import { OAuthQuery, OAuthResponse, withOAuth } from '@/lib/oauth/withOAuth';
 
-async function handler({ code, state, host }: OAuthQuery, _logger: Logger): Promise<OAuthResponse> {
+async function handler({ code, host }: OAuthQuery, _logger: Logger): Promise<OAuthResponse> {
   if (!config.features.oauthRegistration)
     return {
       error: 'OAuth registration is disabled.',
@@ -22,15 +23,18 @@ async function handler({ code, state, host }: OAuthQuery, _logger: Logger): Prom
       error_code: 401,
     };
 
-  if (!code)
+  if (!code) {
+    const linkState = encrypt('link', config.core.secret);
+
     return {
       redirect: googleAuth.url(
         config.oauth.google.clientId!,
         `${config.core.returnHttpsUrls ? 'https' : 'http'}://${host}`,
-        state,
+        linkState,
         config.oauth.google.redirectUri ?? undefined,
       ),
     };
+  }
 
   const body = new URLSearchParams({
     client_id: config.oauth.google.clientId!,

src/pages/api/auth/oauth/oidc.ts

@@ -1,4 +1,5 @@
 import { config } from '@/lib/config';
+import { encrypt } from '@/lib/crypto';
 import Logger from '@/lib/logger';
 import { combine } from '@/lib/middleware/combine';
 import { method } from '@/lib/middleware/method';
@@ -7,7 +8,7 @@ import { oidcAuth } from '@/lib/oauth/providerUtil';
 import { OAuthQuery, OAuthResponse, withOAuth } from '@/lib/oauth/withOAuth';
 
 // thanks to @danejur for this https://github.com/diced/zipline/pull/372
-async function handler({ code, state, host }: OAuthQuery, _logger: Logger): Promise<OAuthResponse> {
+async function handler({ code, host }: OAuthQuery, _logger: Logger): Promise<OAuthResponse> {
   if (!config.features.oauthRegistration)
     return {
       error: 'OAuth registration is disabled.',
@@ -22,16 +23,19 @@ async function handler({ code, state, host }: OAuthQuery, _logger: Logger): Prom
       error_code: 401,
     };
 
-  if (!code)
+  if (!code) {
+    const linkState = encrypt('link', config.core.secret);
+
     return {
       redirect: oidcAuth.url(
         config.oauth.oidc.clientId!,
         `${config.core.returnHttpsUrls ? 'https' : 'http'}://${host}`,
         config.oauth.oidc.authorizeUrl!,
-        state,
+        linkState,
         config.oauth.oidc.redirectUri ?? undefined,
       ),
     };
+  }
 
   const body = new URLSearchParams({
     client_id: config.oauth.oidc.clientId!,