Implement the sign-in screen test app for manual testing

chrome/test/data/extensions/signin_screen_test_app/app/background.js

Index: chrome/test/data/extensions/signin_screen_test_app/app/background.js
diff --git a/chrome/test/data/extensions/signin_screen_test_app/app/background.js b/chrome/test/data/extensions/signin_screen_test_app/app/background.js
index bab4458f6ea84fe671526db66d7be5e5495fb6a1..7ff0d8cb27ce2e479fd1e512e470a716b4b63ee4 100644
--- a/chrome/test/data/extensions/signin_screen_test_app/app/background.js
+++ b/chrome/test/data/extensions/signin_screen_test_app/app/background.js
@@ -2,4 +2,336 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-console.log('The sign-in screen test app loaded');
+// The background script of the test app. The app exposes a certificate to
+// Chrome via chrome.certificateProvider API. This allows to test that the app
+// and the API work by initiating an SSL connection that requests the client
+// certificate. The app also tests displaying of the PIN dialog. Note that the
+// app does NOT implement the real signing operation, therefore it's expected
+// that the SSL connections will fail to establish in the end.
+
+

[pmarko, 2017/05/11 18:24:43]

Consider adding a short comment here that debug output is on the console and
remote debugging is expected to read it because of UI limitations of apps
running on the sign-in screen.

[emaxx, 2017/05/11 20:12:30]

Done.

+// Raw contents of the DER-encoded X.509 certificate.
+// Generated using the following command (assuming that the certificate was
+// bundled in the PKCS #12 archive <path_to_pkcs12_file>):
+//   openssl pkcs12 -in <path_to_pkcs12_file> -nodes | \
+//     openssl x509 -outform der | xxd -i
+// Current certificate expires on Dec 15, 2017.
+var TEST_CERTIFICATE =
+    (new Uint8Array([
+      0x30, 0x82, 0x06, 0x78, 0x30, 0x82, 0x05, 0x60, 0xa0, 0x03, 0x02, 0x01,
+      0x02, 0x02, 0x0a, 0x17, 0xa5, 0x51, 0x7c, 0x00, 0x00, 0x00, 0x00, 0x00,
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+      0x98, 0xb7, 0x64, 0xf2, 0xef, 0x7d, 0xb8, 0x11, 0x25, 0x2d, 0xb9, 0xce,
+      0x9b, 0xb2, 0x4c, 0xde, 0x5b, 0x1e, 0x33, 0x6e, 0xa9, 0x1b, 0xbf, 0x8b,
+      0x1c, 0x9a, 0x00, 0x3b, 0x28, 0x13, 0x00, 0x5c, 0x3c, 0x3b, 0x69, 0x50,
+      0x5e, 0xb6, 0xfd, 0x98
+    ])).buffer;
+
+// Pretend to support all types of hashes.
+var TEST_CERTIFICATE_SUPPORTED_HASHES =

[pmarko, 2017/05/11 18:24:42]

Should we refer to chrome/common/extensions/api/certificate_provider.idl in a
comment here or is that excessive?

[emaxx, 2017/05/11 20:12:30]

Done. Decided to refer to the public documentation though.

+    ['MD5_SHA1', 'SHA1', 'SHA256', 'SHA384', 'SHA512'];
+
+// The expected PIN code.
+var VALID_PIN = '1234';
+
+// The number of wrong attempts after which requesting the PIN will be stopped.
+var MAXIMUM_PIN_FAILED_ATTEMPT_COUNT = 3;
+
+// Data that is used as a response for the sign digest request. This data is
+// random and invalid (as obtaining the real signature requires bundling the
+// extension with a private key and with a piece of cryptographic code).
+var FAKE_SIGN_DIGEST_REQUEST_RESPONSE = (new Uint8Array([1, 2, 3])).buffer;
+
+
+function log(message) {
+  console.log('[Sign-in Screen Test App] ' + message);
+}
+
+function logError(message) {
+  console.error('[Sign-in Screen Test App] ' + message);
+}
+
+// Returns the text dump of the array of objects of CertificateInfo type from
+// the chrome.certificateProvider API.
+function dumpCertificateInfos(certificateInfos) {
+  var transformedList = certificateInfos.map(function(certificateInfo) {
+    var transformedItem = Object.assign({}, certificateInfo);
+    transformedItem.certificate =
+        Array.from(new Uint8Array(certificateInfo.certificate));
+    return transformedItem;
+  });
+  return JSON.stringify(transformedList);
+}
+
+function dumpArrayBuffer(arrayBuffer) {
+  return '[' + (new Uint8Array(arrayBuffer)) + ']';
+}
+
+function arrayBufferEquals(firstArrayBuffer, secondArrayBuffer) {
+  return dumpArrayBuffer(firstArrayBuffer) ==
+      dumpArrayBuffer(secondArrayBuffer);
+}
+
+// Listener for the chrome.certificateProvider.onCertificatesRequested event.
+function certificatesRequestedListener(reportCallback) {
+  log('The onCertificatesRequested event received');
+  var response = [{
+    certificate: TEST_CERTIFICATE,
+    supportedHashes: TEST_CERTIFICATE_SUPPORTED_HASHES
+  }];
+  log('Responding with ' + response.length +
+      ' certificate(s): ' + dumpCertificateInfos(response));
+  reportCallback(response, function(rejectedCertificates) {
+    if (chrome.runtime.lastError) {
+      logError(
+          'Failed to report the certificates: ' +
+          chrome.runtime.lastError.message);
+      return;
+    }
+    if (rejectedCertificates.length) {
+      logError(
+          rejectedCertificates.length + ' certificate(s) were rejected: ' +
+          dumpCertificateInfos(rejectedCertificates));

[pmarko, 2017/05/11 18:24:43]

nit: This seems to be an array of the certificates, not of CertificateInfos
[1][2]. Not that it mattered while we're only providing valid certs :)

[1]
https://cs.chromium.org/chromium/src/chrome/common/extensions/api/certificate...
[2]
https://cs.chromium.org/chromium/src/chrome/browser/extensions/api/certificat...

[emaxx, 2017/05/11 20:12:30]

Oh, good catch. Fixed.

+      return;
+    }
+    log('Successfully reported the certificates');
+  });
+}
+
+// Listener for the chrome.certificateProvider.onSignDigestRequested event.
+function signDigestRequestedListener(request, reportCallback) {
+  log('The onSignDigestRequested event received: signRequestId=' +
+      request.signRequestId + ', digest=' + dumpArrayBuffer(request.digest) +
+      ', hash="' + request.hash +
+      '", certificate=' + dumpArrayBuffer(request.certificate));
+  if (!arrayBufferEquals(request.certificate, TEST_CERTIFICATE)) {
+    logError('The signing request refers to an unknown certificate');
+    abandonSignRequest(request, reportCallback);
+    return;
+  }
+  inputPinAndProcessSignRequest(
+      1 /* attemptNumber */, null /* errorType */, request, reportCallback);
+}
+
+// Requests the PIN from the user and responds to the sign digest request - with
+// some data if the PIN was entered successfully, or with an error otherwise.
+function inputPinAndProcessSignRequest(
+    attemptNumber, errorType, signRequest, signRequestReportCallback) {
+  requestPin(
+      signRequest.signRequestId, attemptNumber, errorType, function(userInput) {
+        if (chrome.runtime.lastError) {
+          logError(
+              'The PIN request failed: ' + chrome.runtime.lastError.message);
+          abandonSignRequest(signRequest, signRequestReportCallback);
+          return;
+        }
+        log('The PIN dialog returned "' + userInput + '"');
+        if (userInput == VALID_PIN) {
+          log('The entered PIN is correct');
+          stopPinRequest(null /* errorType */, signRequest.signRequestId);
+          processSignRequestWithValidPin(
+              signRequest, signRequestReportCallback);
+        } else if (attemptNumber < MAXIMUM_PIN_FAILED_ATTEMPT_COUNT) {
+          log('The entered PIN is wrong, showing the dialog again');
+          inputPinAndProcessSignRequest(
+              attemptNumber + 1, 'INVALID_PIN', signRequest,
+              signRequestReportCallback);
+        } else {
+          log('The entered PIN is wrong, and no attempts left');
+          stopPinRequest('MAX_ATTEMPTS_EXCEEDED', signRequest.signRequestId);
+          abandonSignRequest(signRequest, signRequestReportCallback);
+        }
+      });
+}
+
+// Requests the PIN from the user by displaying the PIN dialog. The passed
+// callback will be called with the string entered by the user, or with null in
+// case of an error.
+function requestPin(signRequestId, attemptNumber, errorType, callback) {
+  var parameters = {signRequestId: signRequestId};
+  if (errorType) {
+    parameters.errorType = errorType;
+    parameters.attemptsLeft =
+        MAXIMUM_PIN_FAILED_ATTEMPT_COUNT - attemptNumber + 1;
+  }
+  log('Requesting PIN with parameters ' + JSON.stringify(parameters));
+  chrome.certificateProvider.requestPin(parameters, function(result) {
+    callback(result ? result.userInput : null);
+  });
+}
+
+// Stops the PIN request: if there is no error passed, the PIN dialog is closed;

[pmarko, 2017/05/11 18:24:42]

nit: if no error is passed (null)

[emaxx, 2017/05/11 20:12:30]

Done.

+// if there is some, then it will be displayed in the inputless dialog.

[pmarko, 2017/05/11 18:24:43]

What does inputless mean here?

[emaxx, 2017/05/11 20:12:30]

Reworded this to a clearer "the dialog that allows no further input".

+function stopPinRequest(errorType, signRequestId) {
+  var parameters = {signRequestId: signRequestId};
+  if (errorType)
+    parameters.errorType = errorType;
+  log('Stopping the PIN request with parameters ' + JSON.stringify(parameters));
+  chrome.certificateProvider.stopPinRequest(parameters, function() {
+    if (chrome.runtime.lastError) {
+      logError(
+          'Failed to stop the PIN request: ' +
+          chrome.runtime.lastError.message);
+      return;
+    }
+    log('Successfully stopped the PIN request');
+  });
+}
+
+// Responds to the signing request after the PIN was entered correctly.
+function processSignRequestWithValidPin(
+    signRequest, signRequestReportCallback) {
+  log('Responding to the signing request with a fake data');
+  signRequestReportCallback(FAKE_SIGN_DIGEST_REQUEST_RESPONSE);
+}
+
+// Responds to the signing request with an error, which unblocks Chrome from
+// waiting for the response from this extension.
+function abandonSignRequest(signRequest, signRequestReportCallback) {
+  log('Responding to the signing request with an error');
+  signRequestReportCallback();
+}
+
+
+log('Loaded');
+if (chrome.certificateProvider) {
+  chrome.certificateProvider.onCertificatesRequested.addListener(
+      certificatesRequestedListener);
+  chrome.certificateProvider.onSignDigestRequested.addListener(
+      signDigestRequestedListener);
+  log('Successfully set up listeners for the certificateProvider API');
+} else {
+  logError('The certificateProvider API is unavailable');
+}