fix: certificate in Apple Game Center auth adapter not validated; thi…

…s fixes a security vulnerability in which authentication could be bypassed using a fake certificate; if you are using the Apple Gamer Center auth adapter it is your responsibility to keep its root certificate up-to-date and we advice you read the security advisory ([GHSA-rh9j-f5f8-rvgc](GHSA-rh9j-f5f8-rvgc))

.github/workflows/ci.yml

@@ -43,6 +43,8 @@ jobs:
       PARSE_SERVER_TEST_CACHE: ${{ matrix.PARSE_SERVER_TEST_CACHE }}
       NODE_VERSION: ${{ matrix.NODE_VERSION }}
     steps:
+      - name: Fix usage of insecure GitHub protocol
+        run: sudo git config --system url."https://github".insteadOf "git://github"
       - uses: actions/checkout@v2
       - name: Use Node.js ${{ matrix.NODE_VERSION }}
         uses: actions/setup-node@v1
@@ -89,6 +91,8 @@ jobs:
       POSTGRES_MAJOR_VERSION: 11
       PARSE_SERVER_TEST_DATABASE_URI: postgres://postgres:postgres@localhost:5432/parse_server_postgres_adapter_test_database
     steps:
+      - name: Fix usage of insecure GitHub protocol
+        run: sudo git config --system url."https://github".insteadOf "git://github"
       - uses: actions/checkout@v2
       - name: Use Node.js 10
         uses: actions/setup-node@v1

spec/AuthenticationAdapters.spec.js

@@ -1644,8 +1644,41 @@ describe('apple signin auth adapter', () => {
 
 describe('Apple Game Center Auth adapter', () => {
   const gcenter = require('../lib/Adapters/Auth/gcenter');
-
+  const fs = require('fs');
+  const testCert = fs.readFileSync(__dirname + '/support/cert/game_center.pem');
+  it('can load adapter', async () => {
+    const options = {
+      gcenter: {
+        rootCertificateUrl:
+          'https://cacerts.digicert.com/DigiCertTrustedG4CodeSigningRSA4096SHA3842021CA1.crt.pem',
+      },
+    };
+    const { adapter, appIds, providerOptions } = authenticationLoader.loadAuthAdapter(
+      'gcenter',
+      options
+    );
+    await adapter.validateAppId(
+      appIds,
+      { publicKeyUrl: 'https://static.gc.apple.com/public-key/gc-prod-4.cer' },
+      providerOptions
+    );
+  });
   it('validateAuthData should validate', async () => {
+    const options = {
+      gcenter: {
+        rootCertificateUrl:
+          'https://cacerts.digicert.com/DigiCertTrustedG4CodeSigningRSA4096SHA3842021CA1.crt.pem',
+      },
+    };
+    const { adapter, appIds, providerOptions } = authenticationLoader.loadAuthAdapter(
+      'gcenter',
+      options
+    );
+    await adapter.validateAppId(
+      appIds,
+      { publicKeyUrl: 'https://static.gc.apple.com/public-key/gc-prod-4.cer' },
+      providerOptions
+    );
     // real token is used
     const authData = {
       id: 'G:1965586982',
@@ -1656,29 +1689,49 @@ describe('Apple Game Center Auth adapter', () => {
       salt: 'DzqqrQ==',
       bundleId: 'cloud.xtralife.gamecenterauth',
     };
-
+    gcenter.cache['https://static.gc.apple.com/public-key/gc-prod-4.cer'] = testCert;
     await gcenter.validateAuthData(authData);
   });
 
   it('validateAuthData invalid signature id', async () => {
+    const { adapter, appIds, providerOptions } = authenticationLoader.loadAuthAdapter(
+      'gcenter',
+      {}
+    );
+    await adapter.validateAppId(
+      appIds,
+      { publicKeyUrl: 'https://static.gc.apple.com/public-key/gc-prod-4.cer' },
+      providerOptions
+    );
     const authData = {
       id: 'G:1965586982',
-      publicKeyUrl: 'https://static.gc.apple.com/public-key/gc-prod-4.cer',
+      publicKeyUrl: 'https://static.gc.apple.com/public-key/gc-prod-6.cer',
       timestamp: 1565257031287,
       signature: '1234',
       salt: 'DzqqrQ==',
-      bundleId: 'cloud.xtralife.gamecenterauth',
+      bundleId: 'com.example.com',
     };
-
-    try {
-      await gcenter.validateAuthData(authData);
-      fail();
-    } catch (e) {
-      expect(e.message).toBe('Apple Game Center - invalid signature');
-    }
+    await expectAsync(gcenter.validateAuthData(authData)).toBeRejectedWith(
+      new Parse.Error(Parse.Error.SCRIPT_FAILED, 'Apple Game Center - invalid signature')
+    );
   });
 
   it('validateAuthData invalid public key http url', async () => {
+    const options = {
+      gcenter: {
+        rootCertificateUrl:
+          'https://cacerts.digicert.com/DigiCertTrustedG4CodeSigningRSA4096SHA3842021CA1.crt.pem',
+      },
+    };
+    const { adapter, appIds, providerOptions } = authenticationLoader.loadAuthAdapter(
+      'gcenter',
+      options
+    );
+    await adapter.validateAppId(
+      appIds,
+      { publicKeyUrl: 'https://static.gc.apple.com/public-key/gc-prod-4.cer' },
+      providerOptions
+    );
     const publicKeyUrls = [
       'example.com',
       'http://static.gc.apple.com/public-key/gc-prod-4.cer',
@@ -1706,6 +1759,78 @@ describe('Apple Game Center Auth adapter', () => {
       )
     );
   });
+
+  it('should not validate Symantec Cert', async () => {
+    const options = {
+      gcenter: {
+        rootCertificateUrl:
+          'https://cacerts.digicert.com/DigiCertTrustedG4CodeSigningRSA4096SHA3842021CA1.crt.pem',
+      },
+    };
+    const { adapter, appIds, providerOptions } = authenticationLoader.loadAuthAdapter(
+      'gcenter',
+      options
+    );
+    await adapter.validateAppId(
+      appIds,
+      { publicKeyUrl: 'https://static.gc.apple.com/public-key/gc-prod-4.cer' },
+      providerOptions
+    );
+    expect(() =>
+      gcenter.verifyPublicKeyIssuer(
+        testCert,
+        'https://static.gc.apple.com/public-key/gc-prod-4.cer'
+      )
+    );
+  });
+
+  it('adapter should load default cert', async () => {
+    const options = {
+      gcenter: {},
+    };
+    const { adapter, appIds, providerOptions } = authenticationLoader.loadAuthAdapter(
+      'gcenter',
+      options
+    );
+    await adapter.validateAppId(
+      appIds,
+      { publicKeyUrl: 'https://static.gc.apple.com/public-key/gc-prod-4.cer' },
+      providerOptions
+    );
+    const previous = new Date();
+    await adapter.validateAppId(
+      appIds,
+      { publicKeyUrl: 'https://static.gc.apple.com/public-key/gc-prod-4.cer' },
+      providerOptions
+    );
+
+    const duration = new Date().getTime() - previous.getTime();
+    expect(duration).toEqual(0);
+  });
+
+  it('adapter should throw', async () => {
+    const options = {
+      gcenter: {
+        rootCertificateUrl: 'https://example.com',
+      },
+    };
+    const { adapter, appIds, providerOptions } = authenticationLoader.loadAuthAdapter(
+      'gcenter',
+      options
+    );
+    await expectAsync(
+      adapter.validateAppId(
+        appIds,
+        { publicKeyUrl: 'https://static.gc.apple.com/public-key/gc-prod-4.cer' },
+        providerOptions
+      )
+    ).toBeRejectedWith(
+      new Parse.Error(
+        Parse.Error.OBJECT_NOT_FOUND,
+        'Apple Game Center auth adapter parameter `rootCertificateURL` is invalid.'
+      )
+    );
+  });
 });
 
 describe('phant auth adapter', () => {

spec/support/cert/game_center.pem

@@ -0,0 +1,28 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----

src/Adapters/Auth/gcenter.js

@@ -14,7 +14,8 @@ const authData = {
 const { Parse } = require('parse/node');
 const crypto = require('crypto');
 const https = require('https');
-
+const { pki } = require('node-forge');
+const ca = { cert: null, url: null };
 const cache = {}; // (publicKey -> cert) cache
 
 function verifyPublicKeyUrl(publicKeyUrl) {
@@ -52,39 +53,53 @@ async function getAppleCertificate(publicKeyUrl) {
     path: url.pathname,
     method: 'HEAD',
   };
-  const headers = await new Promise((resolve, reject) =>
+  const cert_headers = await new Promise((resolve, reject) =>
     https.get(headOptions, res => resolve(res.headers)).on('error', reject)
   );
+  const validContentTypes = ['application/x-x509-ca-cert', 'application/pkix-cert'];
   if (
-    headers['content-type'] !== 'application/pkix-cert' ||
-    headers['content-length'] == null ||
-    headers['content-length'] > 10000
+    !validContentTypes.includes(cert_headers['content-type']) ||
+    cert_headers['content-length'] == null ||
+    cert_headers['content-length'] > 10000
   ) {
     throw new Parse.Error(
       Parse.Error.OBJECT_NOT_FOUND,
       `Apple Game Center - invalid publicKeyUrl: ${publicKeyUrl}`
     );
   }
+  const { certificate, headers } = await getCertificate(publicKeyUrl);
+  if (headers['cache-control']) {
+    const expire = headers['cache-control'].match(/max-age=([0-9]+)/);
+    if (expire) {
+      cache[publicKeyUrl] = certificate;
+      // we'll expire the cache entry later, as per max-age
+      setTimeout(() => {
+        delete cache[publicKeyUrl];
+      }, parseInt(expire[1], 10) * 1000);
+    }
+  }
+  return verifyPublicKeyIssuer(certificate, publicKeyUrl);
+}
+
+function getCertificate(url, buffer) {
   return new Promise((resolve, reject) => {
     https
-      .get(publicKeyUrl, res => {
-        let data = '';
+      .get(url, res => {
+        const data = [];
         res.on('data', chunk => {
-          data += chunk.toString('base64');
+          data.push(chunk);
         });
         res.on('end', () => {
-          const cert = convertX509CertToPEM(data);
-          if (res.headers['cache-control']) {
-            var expire = res.headers['cache-control'].match(/max-age=([0-9]+)/);
-            if (expire) {
-              cache[publicKeyUrl] = cert;
-              // we'll expire the cache entry later, as per max-age
-              setTimeout(() => {
-                delete cache[publicKeyUrl];
-              }, parseInt(expire[1], 10) * 1000);
-            }
+          if (buffer) {
+            resolve({ certificate: Buffer.concat(data), headers: res.headers });
+            return;
           }
-          resolve(cert);
+          let cert = '';
+          for (const chunk of data) {
+            cert += chunk.toString('base64');
+          }
+          const certificate = convertX509CertToPEM(cert);
+          resolve({ certificate, headers: res.headers });
         });
       })
       .on('error', reject);
@@ -115,6 +130,30 @@ function verifySignature(publicKey, authData) {
   }
 }
 
+function verifyPublicKeyIssuer(cert, publicKeyUrl) {
+  const publicKeyCert = pki.certificateFromPem(cert);
+  if (!ca.cert) {
+    throw new Parse.Error(
+      Parse.Error.OBJECT_NOT_FOUND,
+      'Apple Game Center auth adapter parameter `rootCertificateURL` is invalid.'
+    );
+  }
+  try {
+    if (!ca.cert.verify(publicKeyCert)) {
+      throw new Parse.Error(
+        Parse.Error.OBJECT_NOT_FOUND,
+        `Apple Game Center - invalid publicKeyUrl: ${publicKeyUrl}`
+      );
+    }
+  } catch (e) {
+    throw new Parse.Error(
+      Parse.Error.OBJECT_NOT_FOUND,
+      `Apple Game Center - invalid publicKeyUrl: ${publicKeyUrl}`
+    );
+  }
+  return cert;
+}
+
 // Returns a promise that fulfills if this user id is valid.
 async function validateAuthData(authData) {
   if (!authData.id) {
@@ -126,11 +165,31 @@ async function validateAuthData(authData) {
 }
 
 // Returns a promise that fulfills if this app id is valid.
-function validateAppId() {
-  return Promise.resolve();
+async function validateAppId(appIds, authData, options = {}) {
+  if (!options.rootCertificateUrl) {
+    options.rootCertificateUrl =
+      'https://cacerts.digicert.com/DigiCertTrustedG4CodeSigningRSA4096SHA3842021CA1.crt.pem';
+  }
+  if (ca.url === options.rootCertificateUrl) {
+    return;
+  }
+  const { certificate, headers } = await getCertificate(options.rootCertificateUrl, true);
+  if (
+    headers['content-type'] !== 'application/x-pem-file' ||
+    headers['content-length'] == null ||
+    headers['content-length'] > 10000
+  ) {
+    throw new Parse.Error(
+      Parse.Error.OBJECT_NOT_FOUND,
+      'Apple Game Center auth adapter parameter `rootCertificateURL` is invalid.'
+    );
+  }
+  ca.cert = pki.certificateFromPem(certificate);
+  ca.url = options.rootCertificateUrl;
 }
 
 module.exports = {
   validateAppId,
   validateAuthData,
+  cache,
 };