From a5605fc89fa5d19f08a50d4a30c9b02e332436f2 Mon Sep 17 00:00:00 2001
From: Mario Danic <mario@lovelyhq.com>
Date: Fri, 15 Feb 2019 10:59:33 +0100
Subject: [PATCH] Begin implementing biometric magic

Signed-off-by: Mario Danic <mario@lovelyhq.com>
---
 app/build.gradle                              |  2 +-
 app/src/main/AndroidManifest.xml              |  4 ++
 .../talk/activities/BaseActivity.java         | 39 +++++++++++++++++-
 .../nextcloud/talk/utils/HandlerExecutor.java | 41 +++++++++++++++++++
 .../nextcloud/talk/utils/SecurityUtils.java   | 26 ++++++++++++
 app/src/main/res/values/strings.xml           |  2 +
 6 files changed, 112 insertions(+), 2 deletions(-)
 create mode 100644 app/src/main/java/com/nextcloud/talk/utils/HandlerExecutor.java

diff --git a/app/build.gradle b/app/build.gradle
index 35a06ea24..1a9310a4d 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -120,7 +120,7 @@ dependencies {
     implementation "android.arch.work:work-rxjava2:${workVersion}"
     androidTestImplementation "android.arch.work:work-testing:${workVersion}"
 
-
+    implementation 'androidx.biometric:biometric:1.0.0-alpha03'
     implementation "androidx.lifecycle:lifecycle-extensions:2.0.0"
 
     implementation 'androidx.multidex:multidex:2.0.0'
diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index 31e9392d2..78dbc8c2c 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -34,6 +34,10 @@
     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
     <uses-permission android:name="android.permission.WAKE_LOCK"/>
 
+    <uses-permission android:name="android.permission.USE_BIOMETRIC" />
+    <!-- This permission is deprecated in Android P  -->
+    <uses-permission android:name="android.permission.USE_FINGERPRINT" />
+
     <application
         android:name=".application.NextcloudTalkApplication"
         android:allowBackup="true"
diff --git a/app/src/main/java/com/nextcloud/talk/activities/BaseActivity.java b/app/src/main/java/com/nextcloud/talk/activities/BaseActivity.java
index eaf6e645b..6f40fd0a9 100644
--- a/app/src/main/java/com/nextcloud/talk/activities/BaseActivity.java
+++ b/app/src/main/java/com/nextcloud/talk/activities/BaseActivity.java
@@ -26,16 +26,19 @@ import android.content.Context;
 import android.content.Intent;
 import android.os.Build;
 import android.os.Bundle;
+import android.os.Handler;
 import android.util.Log;
 import android.view.WindowManager;
 import android.webkit.SslErrorHandler;
 import androidx.annotation.Nullable;
 import androidx.annotation.RequiresApi;
 import androidx.appcompat.app.AppCompatActivity;
+import androidx.biometric.BiometricPrompt;
 import autodagger.AutoInjector;
 import com.nextcloud.talk.R;
 import com.nextcloud.talk.application.NextcloudTalkApplication;
 import com.nextcloud.talk.events.CertificateEvent;
+import com.nextcloud.talk.utils.HandlerExecutor;
 import com.nextcloud.talk.utils.SecurityUtils;
 import com.nextcloud.talk.utils.preferences.AppPreferences;
 import com.nextcloud.talk.utils.ssl.MagicTrustManager;
@@ -49,6 +52,7 @@ import java.security.cert.CertificateParsingException;
 import java.security.cert.X509Certificate;
 import java.text.DateFormat;
 import java.util.List;
+import java.util.concurrent.Executor;
 
 @AutoInjector(NextcloudTalkApplication.class)
 public class BaseActivity extends AppCompatActivity {
@@ -61,6 +65,9 @@ public class BaseActivity extends AppCompatActivity {
     @Inject
     AppPreferences appPreferences;
 
+    @Inject
+    Context context;
+
     private KeyguardManager keyguardManager;
 
     @Override
@@ -93,11 +100,33 @@ public class BaseActivity extends AppCompatActivity {
         keyguardManager = (KeyguardManager) getSystemService(Context.KEYGUARD_SERVICE);
         if (keyguardManager != null && keyguardManager.isKeyguardSecure() && appPreferences.getIsScreenLocked()) {
             if (!SecurityUtils.checkIfWeAreAuthenticated(appPreferences.getScreenLockTimeout())) {
-                showAuthenticationScreen();
+                if (SecurityUtils.isFingerprintAvailable(context)) {
+                    showBiometricDialog();
+                } else {
+                    showAuthenticationScreen();
+                }
             }
         }
     }
 
+    @RequiresApi(api = Build.VERSION_CODES.M)
+    private void showBiometricDialog() {
+        final BiometricPrompt.PromptInfo promptInfo = new BiometricPrompt.PromptInfo.Builder()
+                .setTitle(String.format(context.getString(R.string.nc_biometric_unlock), context.getString(R.string.nc_app_name)))
+                .setNegativeButtonText(context.getString(R.string.nc_cancel))
+                .build();
+
+        Executor mainExecutor = new HandlerExecutor(new Handler(getMainLooper()));
+
+        final BiometricPrompt biometricPrompt = new BiometricPrompt(this, mainExecutor,
+                new BiometricPrompt.AuthenticationCallback() {
+
+                }
+        );
+
+        biometricPrompt.authenticate(promptInfo, SecurityUtils.getCryptoObject());
+    }
+
     private void showAuthenticationScreen() {
         Intent intent = keyguardManager.createConfirmDeviceCredentialIntent(null, null);
         if (intent != null) {
@@ -190,4 +219,12 @@ public class BaseActivity extends AppCompatActivity {
         super.onStop();
         eventBus.unregister(this);
     }
+
+    @Override
+    public void onPause() {
+        super.onPause();
+        if (!disposable.isDisposed()) {
+            disposable.dispose();
+        }
+    }
 }
diff --git a/app/src/main/java/com/nextcloud/talk/utils/HandlerExecutor.java b/app/src/main/java/com/nextcloud/talk/utils/HandlerExecutor.java
new file mode 100644
index 000000000..89521f659
--- /dev/null
+++ b/app/src/main/java/com/nextcloud/talk/utils/HandlerExecutor.java
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.nextcloud.talk.utils;
+import android.os.Handler;
+import androidx.annotation.NonNull;
+
+import java.util.concurrent.Executor;
+import java.util.concurrent.RejectedExecutionException;
+/**
+ * An adapter {@link Executor} that posts all executed tasks onto the given
+ * {@link Handler}.
+ *
+ * @hide
+ */
+public class HandlerExecutor implements Executor {
+    private final Handler mHandler;
+
+    public HandlerExecutor(@NonNull Handler handler) {
+        mHandler = handler;
+    }
+
+    @Override
+    public void execute(Runnable command) {
+        if (!mHandler.post(command)) {
+            throw new RejectedExecutionException(mHandler + " is shutting down");
+        }
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/nextcloud/talk/utils/SecurityUtils.java b/app/src/main/java/com/nextcloud/talk/utils/SecurityUtils.java
index 90424b7ee..0074c8863 100644
--- a/app/src/main/java/com/nextcloud/talk/utils/SecurityUtils.java
+++ b/app/src/main/java/com/nextcloud/talk/utils/SecurityUtils.java
@@ -20,6 +20,7 @@
 
 package com.nextcloud.talk.utils;
 
+import android.content.Context;
 import android.content.res.Resources;
 import android.os.Build;
 import android.security.keystore.KeyGenParameterSpec;
@@ -28,6 +29,8 @@ import android.security.keystore.KeyProperties;
 import android.security.keystore.UserNotAuthenticatedException;
 import android.util.Log;
 import androidx.annotation.RequiresApi;
+import androidx.biometric.BiometricPrompt;
+import androidx.core.hardware.fingerprint.FingerprintManagerCompat;
 import com.nextcloud.talk.R;
 import com.nextcloud.talk.application.NextcloudTalkApplication;
 
@@ -77,6 +80,24 @@ public class SecurityUtils {
         }
     }
 
+    @RequiresApi(api = Build.VERSION_CODES.M)
+    public static BiometricPrompt.CryptoObject getCryptoObject() {
+        Cipher cipher = null;
+        try {
+            cipher = Cipher.getInstance(KeyProperties.KEY_ALGORITHM_AES + "/" + KeyProperties.BLOCK_MODE_GCM + "/" + KeyProperties.ENCRYPTION_PADDING_NONE);
+        } catch (NoSuchAlgorithmException e) {
+            Log.w(TAG, e.getLocalizedMessage());
+        } catch (NoSuchPaddingException e) {
+            Log.w(TAG, e.getLocalizedMessage());
+        }
+
+        BiometricPrompt.CryptoObject cryptoObject = null;
+        if (cipher != null) {
+            cryptoObject = new BiometricPrompt.CryptoObject(cipher);
+        }
+
+        return cryptoObject;
+    }
     @RequiresApi(api = Build.VERSION_CODES.M)
     public static void createKey(String validity) {
         try {
@@ -109,4 +130,9 @@ public class SecurityUtils {
         int indexOfValidity = entryValues.indexOf(validity);
         return entryIntValues[indexOfValidity];
     }
+
+    public static boolean isFingerprintAvailable(Context context) {
+        FingerprintManagerCompat fingerprintManager = FingerprintManagerCompat.from(context);
+        return fingerprintManager.isHardwareDetected() && fingerprintManager.hasEnrolledFingerprints();
+    }
 }
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index e7e96bd00..ba81ddcd9 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -112,6 +112,8 @@
     <string name="nc_screen_lock_timeout_three_hundred">300</string>
     <string name="nc_screen_lock_timeout_six_hundred">600</string>
 
+    <string name="nc_biometric_unlock">Unlock %1$s</string>
+    <string name="nc_cancel">Cancel</string>
 
     <string name="nc_no_proxy">No proxy</string>
     <string name="nc_username">Username</string>