Require a CSRF code for Twitter and JIRA (OAuth 1) logins

Summary:
OAuth1 doesn't have anything like the `state` parameter, and I overlooked that we need to shove one in there somewhere. Append it to the callback URI. This functions like `state` in OAuth2.

Without this, an attacker can trick a user into logging into Phabricator with an account the attacker controls.

Test Plan:
  - Logged in with JIRA.
  - Logged in with Twitter.
  - Logged in with Facebook (an OAuth2 provider).
  - Linked a Twitter account.
  - Linked a Facebook account.
  - Jiggered codes in URIs and verified that I got the exceptions I expected.

Reviewers: btrahan, arice

Reviewed By: arice

CC: arice, chad, aran

Differential Revision: https://secure.phabricator.com/D8318

src/applications/auth/application/PhabricatorApplicationAuth.php

@@ -76,7 +76,8 @@ final class PhabricatorApplicationAuth extends PhabricatorApplication {
           '(?P<action>enable|disable)/(?P<id>\d+)/' =>
             'PhabricatorAuthDisableController',
         ),
-        'login/(?P<pkey>[^/]+)/' => 'PhabricatorAuthLoginController',
+        'login/(?P<pkey>[^/]+)/(?:(?P<extra>[^/]+)/)?' =>
+          'PhabricatorAuthLoginController',
         'register/(?:(?P<akey>[^/]+)/)?' => 'PhabricatorAuthRegisterController',
         'start/' => 'PhabricatorAuthStartController',
         'validate/' => 'PhabricatorAuthValidateController',

src/applications/auth/controller/PhabricatorAuthLoginController.php

@@ -4,6 +4,7 @@ final class PhabricatorAuthLoginController
   extends PhabricatorAuthController {
 
   private $providerKey;
+  private $extraURIData;
   private $provider;
 
   public function shouldRequireLogin() {
@@ -12,6 +13,11 @@ final class PhabricatorAuthLoginController
 
   public function willProcessRequest(array $data) {
     $this->providerKey = $data['pkey'];
+    $this->extraURIData = idx($data, 'extra');
+  }
+
+  public function getExtraURIData() {
+    return $this->extraURIData;
   }
 
   public function processRequest() {

src/applications/auth/provider/PhabricatorAuthProvider.php

@@ -441,4 +441,38 @@ abstract class PhabricatorAuthProvider {
     return null;
   }
 
+  protected function getAuthCSRFCode(AphrontRequest $request) {
+    $phcid = $request->getCookie(PhabricatorCookies::COOKIE_CLIENTID);
+    if (!strlen($phcid)) {
+      throw new Exception(
+        pht(
+          'Your browser did not submit a "%s" cookie with client state '.
+          'information in the request. Check that cookies are enabled. '.
+          'If this problem persists, you may need to clear your cookies.',
+          PhabricatorCookies::COOKIE_CLIENTID));
+    }
+
+    return PhabricatorHash::digest($phcid);
+  }
+
+  protected function verifyAuthCSRFCode(AphrontRequest $request, $actual) {
+    $expect = $this->getAuthCSRFCode($request);
+
+    if (!strlen($actual)) {
+      throw new Exception(
+        pht(
+          'The authentication provider did not return a client state '.
+          'parameter in its response, but one was expected. If this '.
+          'problem persists, you may need to clear your cookies.'));
+    }
+
+    if ($actual !== $expect) {
+      throw new Exception(
+        pht(
+          'The authentication provider did not return the correct client '.
+          'state parameter in its response. If this problem persists, you may '.
+          'need to clear your cookies.'));
+    }
+  }
+
 }

src/applications/auth/provider/PhabricatorAuthProviderOAuth.php

@@ -35,9 +35,7 @@ abstract class PhabricatorAuthProviderOAuth extends PhabricatorAuthProvider {
 
   protected function renderLoginForm(AphrontRequest $request, $mode) {
     $adapter = $this->getAdapter();
-    $adapter->setState(
+    $adapter->setState($this->getAuthCSRFCode($request));
-      PhabricatorHash::digest(
-        $request->getCookie(PhabricatorCookies::COOKIE_CLIENTID)));
 
     $scope = $request->getStr('scope');
     if ($scope) {
@@ -71,6 +69,8 @@ abstract class PhabricatorAuthProviderOAuth extends PhabricatorAuthProvider {
       return array($account, $response);
     }
 
+    $this->verifyAuthCSRFCode($request, $request->getStr('state'));
+
     $code = $request->getStr('code');
     if (!strlen($code)) {
       $response = $controller->buildProviderErrorResponse(
@@ -82,30 +82,6 @@ abstract class PhabricatorAuthProviderOAuth extends PhabricatorAuthProvider {
       return array($account, $response);
     }
 
-    if ($adapter->supportsStateParameter()) {
-      $phcid = $request->getCookie(PhabricatorCookies::COOKIE_CLIENTID);
-      if (!strlen($phcid)) {
-        $response = $controller->buildProviderErrorResponse(
-          $this,
-          pht(
-            'Your browser did not submit a "%s" cookie with OAuth state '.
-            'information in the request. Check that cookies are enabled. '.
-            'If this problem persists, you may need to clear your cookies.',
-            PhabricatorCookies::COOKIE_CLIENTID));
-      }
-
-      $state = $request->getStr('state');
-      $expect = PhabricatorHash::digest($phcid);
-      if ($state !== $expect) {
-        $response = $controller->buildProviderErrorResponse(
-          $this,
-          pht(
-            'The OAuth provider did not return the correct "state" parameter '.
-            'in its response. If this problem persists, you may need to clear '.
-            'your cookies.'));
-      }
-    }
-
     $adapter->setCode($code);
 
     // NOTE: As a side effect, this will cause the OAuth adapter to request

src/applications/auth/provider/PhabricatorAuthProviderOAuth1.php

@@ -55,6 +55,15 @@ abstract class PhabricatorAuthProviderOAuth1 extends PhabricatorAuthProvider {
     $response = null;
 
     if ($request->isHTTPPost()) {
+      // Add a CSRF code to the callback URI, which we'll verify when
+      // performing the login.
+
+      $client_code = $this->getAuthCSRFCode($request);
+
+      $callback_uri = $adapter->getCallbackURI();
+      $callback_uri = $callback_uri.$client_code.'/';
+      $adapter->setCallbackURI($callback_uri);
+
       $uri = $adapter->getClientRedirectURI();
       $response = id(new AphrontRedirectResponse())->setURI($uri);
       return array($account, $response);
@@ -70,6 +79,8 @@ abstract class PhabricatorAuthProviderOAuth1 extends PhabricatorAuthProvider {
     // NOTE: You can get here via GET, this should probably be a bit more
     // user friendly.
 
+    $this->verifyAuthCSRFCode($request, $controller->getExtraURIData());
+
     $token = $request->getStr('oauth_token');
     $verifier = $request->getStr('oauth_verifier');