ScreenLock: Implement fingerprint unlocking with BiometricPromptCompat

briar-android/build.gradle

@@ -33,6 +33,7 @@ dependencies {
 	implementation 'com.google.zxing:core:3.3.0'
 	implementation 'uk.co.samuelwall:material-tap-target-prompt:2.8.0'
 	implementation 'com.vanniktech:emoji-google:0.5.1'
+	implementation 'moe.feng.support.biometricprompt:library:1.0.1'
 
 	annotationProcessor 'com.google.dagger:dagger-compiler:2.0.2'
 
@@ -75,8 +76,8 @@ def getStdout = { command, defaultValue ->
 }
 
 android {
-	compileSdkVersion 27
-	buildToolsVersion '27.0.3'
+	compileSdkVersion 28
+	buildToolsVersion '28.0.2'
 
 	defaultConfig {
 		minSdkVersion 15

briar-android/src/main/AndroidManifest.xml

 <?xml version="1.0" encoding="utf-8"?>
 <manifest
 	package="org.briarproject.briar"
-	xmlns:android="http://schemas.android.com/apk/res/android">
+	xmlns:android="http://schemas.android.com/apk/res/android"
+	xmlns:tools="http://schemas.android.com/tools">
+
+	<uses-sdk tools:overrideLibrary="moe.feng.support.biometricprompt"/>
 
 	<uses-feature android:name="android.hardware.bluetooth" android:required="false"/>
 	<uses-feature android:name="android.hardware.camera" android:required="false"/>
@@ -17,6 +20,8 @@
 	<uses-permission android:name="android.permission.WAKE_LOCK" />
 	<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>
 	<uses-permission-sdk-23 android:name="android.permission.REQUEST_IGNORE_BATTERY_OPTIMIZATIONS"/>
+	<uses-permission-sdk-23 android:name="android.permission.USE_FINGERPRINT" />
+	<uses-permission-sdk-23 android:name="android.permission.USE_BIOMETRIC" />
 
 	<application
 		android:name="org.briarproject.briar.android.BriarApplicationImpl"

briar-android/src/main/java/org/briarproject/briar/android/login/UnlockActivity.java

@@ -3,9 +3,12 @@ package org.briarproject.briar.android.login;
 import android.app.KeyguardManager;
 import android.content.Intent;
 import android.os.Bundle;
+import android.os.CancellationSignal;
+import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 import android.support.annotation.RequiresApi;
 import android.widget.Button;
+import android.widget.Toast;
 
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
@@ -18,8 +21,19 @@ import java.util.logging.Logger;
 
 import javax.inject.Inject;
 
+import moe.feng.support.biometricprompt.BiometricPromptCompat;
+import moe.feng.support.biometricprompt.BiometricPromptCompat.Builder;
+import moe.feng.support.biometricprompt.BiometricPromptCompat.IAuthenticationCallback;
+import moe.feng.support.biometricprompt.BiometricPromptCompat.IAuthenticationResult;
+
 import static android.os.Build.VERSION.SDK_INT;
+import static moe.feng.support.biometricprompt.BiometricPromptCompat.BIOMETRIC_ERROR_CANCELED;
+import static moe.feng.support.biometricprompt.BiometricPromptCompat.BIOMETRIC_ERROR_LOCKOUT;
+import static moe.feng.support.biometricprompt.BiometricPromptCompat.BIOMETRIC_ERROR_LOCKOUT_PERMANENT;
+import static moe.feng.support.biometricprompt.BiometricPromptCompat.BIOMETRIC_ERROR_USER_CANCELED;
 import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_KEYGUARD_UNLOCK;
+import static org.briarproject.briar.android.util.UiUtils.hasKeyguardLock;
+import static org.briarproject.briar.android.util.UiUtils.hasUsableFingerprint;
 
 @RequiresApi(21)
 @MethodsNotNullByDefault
@@ -46,7 +60,7 @@ public class UnlockActivity extends BaseActivity {
 		setContentView(R.layout.activity_unlock);
 
 		Button button = findViewById(R.id.unlock);
-		button.setOnClickListener(view -> requestKeyguardUnlock());
+		button.setOnClickListener(view -> requestUnlock());
 
 		keyguardShown = state != null && state.getBoolean(KEYGUARD_SHOWN);
 	}
@@ -83,18 +97,80 @@ public class UnlockActivity extends BaseActivity {
 		// Check if app is still locked, lockable
 		// and not finishing (which is possible if recreated)
 		if (!keyguardShown && lockManager.isLocked() && !isFinishing()) {
-			requestKeyguardUnlock();
+			requestUnlock();
 		} else if (!lockManager.isLocked()) {
 			setResult(RESULT_OK);
 			finish();
 		}
 	}
 
+	private void requestUnlock() {
+		if (hasUsableFingerprint(this)) {
+			requestFingerprintUnlock();
+		} else {
+			requestKeyguardUnlock();
+		}
+	}
+
 	@Override
 	public void onBackPressed() {
 		moveTaskToBack(true);
 	}
 
+	private void requestFingerprintUnlock() {
+		BiometricPromptCompat biometricPrompt = new Builder(this)
+				.setTitle(R.string.lock_unlock)
+				.setDescription(R.string.lock_unlock_fingerprint_description)
+				.setNegativeButton(R.string.lock_unlock_password,
+						(dialog, which) -> {
+							requestKeyguardUnlock();
+						})
+				.build();
+		CancellationSignal signal = new CancellationSignal();
+		biometricPrompt.authenticate(signal, new IAuthenticationCallback() {
+			@Override
+			public void onAuthenticationError(int errorCode,
+					@Nullable CharSequence errString) {
+				// when back button is pressed while fingerprint dialog shows
+				if (errorCode == BIOMETRIC_ERROR_CANCELED ||
+						errorCode == BIOMETRIC_ERROR_USER_CANCELED) {
+					finish();
+				}
+				// locked out due to 5 failed attempts, lasts for 30 seconds
+				else if (errorCode == BIOMETRIC_ERROR_LOCKOUT ||
+						errorCode == BIOMETRIC_ERROR_LOCKOUT_PERMANENT) {
+					if (hasKeyguardLock(UnlockActivity.this)) {
+						requestKeyguardUnlock();
+					} else {
+						// normally fingerprints require a screen lock, but
+						// who knows if that's true for all devices out there
+						Toast.makeText(UnlockActivity.this, errString,
+								Toast.LENGTH_LONG).show();
+						finish();
+					}
+				} else {
+					Toast.makeText(UnlockActivity.this, errString,
+							Toast.LENGTH_LONG).show();
+				}
+			}
+
+			@Override
+			public void onAuthenticationHelp(int helpCode,
+					@Nullable CharSequence helpString) {
+			}
+
+			@Override
+			public void onAuthenticationSucceeded(
+					@NonNull IAuthenticationResult result) {
+				unlock();
+			}
+
+			@Override
+			public void onAuthenticationFailed() {
+			}
+		});
+	}
+
 	private void requestKeyguardUnlock() {
 		KeyguardManager keyguardManager =
 				(KeyguardManager) getSystemService(KEYGUARD_SERVICE);

briar-android/src/main/java/org/briarproject/briar/android/util/UiUtils.java

@@ -59,6 +59,8 @@ import static android.text.format.DateUtils.FORMAT_ABBREV_TIME;
 import static android.text.format.DateUtils.FORMAT_SHOW_DATE;
 import static android.text.format.DateUtils.MINUTE_IN_MILLIS;
 import static android.text.format.DateUtils.WEEK_IN_MILLIS;
+import static moe.feng.support.biometricprompt.BiometricPromptCompat.hasEnrolledFingerprints;
+import static moe.feng.support.biometricprompt.BiometricPromptCompat.isHardwareDetected;
 import static org.briarproject.briar.BuildConfig.APPLICATION_ID;
 import static org.briarproject.briar.android.TestingConstants.EXPIRY_DATE;
 
@@ -261,6 +263,10 @@ public class UiUtils {
 	}
 
 	public static boolean hasScreenLock(Context ctx) {
+		return hasKeyguardLock(ctx) || hasUsableFingerprint(ctx);
+	}
+
+	public static boolean hasKeyguardLock(Context ctx) {
 		if (SDK_INT < 21) return false;
 		KeyguardManager keyguardManager =
 				(KeyguardManager) ctx.getSystemService(KEYGUARD_SERVICE);
@@ -271,6 +277,11 @@ public class UiUtils {
 				(SDK_INT >= 23 && keyguardManager.isDeviceSecure());
 	}
 
+	public static boolean hasUsableFingerprint(Context ctx) {
+		return SDK_INT >= 23 && isHardwareDetected(ctx) &&
+				hasEnrolledFingerprints(ctx);
+	}
+
 	public static void triggerFeedback(AndroidExecutor androidExecutor) {
 		androidExecutor.runOnBackgroundThread(
 				() -> ACRA.getErrorReporter()

briar-android/src/main/res/layout/activity_unlock.xml

@@ -14,27 +14,13 @@
 		android:layout_height="150dp"
 		android:layout_margin="@dimen/margin_large"
 		android:src="@drawable/splash_screen"
-		app:layout_constraintBottom_toTopOf="@+id/is_locked"
+		app:layout_constraintBottom_toTopOf="@+id/unlock"
 		app:layout_constraintEnd_toEndOf="parent"
 		app:layout_constraintStart_toStartOf="parent"
 		app:layout_constraintTop_toTopOf="parent"
-		app:layout_constraintVertical_chainStyle="spread"
+		app:layout_constraintVertical_bias="0.1"
 		app:tint="?attr/colorControlNormal"/>
 
-	<TextView
-		android:id="@+id/is_locked"
-		android:layout_width="wrap_content"
-		android:layout_height="wrap_content"
-		android:layout_margin="@dimen/margin_large"
-		android:gravity="center"
-		android:text="@string/lock_is_locked"
-		android:textSize="@dimen/text_size_xlarge"
-		app:layout_constraintBottom_toTopOf="@+id/unlock"
-		app:layout_constraintEnd_toEndOf="parent"
-		app:layout_constraintStart_toStartOf="parent"
-		app:layout_constraintTop_toBottomOf="@+id/image"
-		app:layout_constraintVertical_chainStyle="spread"/>
-
 	<Button
 		android:id="@+id/unlock"
 		style="@style/BriarButton"

briar-android/src/main/res/values/strings.xml

@@ -475,6 +475,8 @@
 	<!-- App Locking -->
 	<string name="lock_unlock">Unlock Briar</string>
 	<string name="lock_unlock_verbose">Enter your device PIN, pattern or password to unlock Briar</string>
+	<string name="lock_unlock_fingerprint_description">Touch your fingerprint sensor with the registered finger to continue</string>
+	<string name="lock_unlock_password">Use Password</string>
 	<string name="lock_is_locked">Briar is locked</string>
 	<string name="lock_tap_to_unlock">Tap to unlock</string>
 

briar-android/witness.gradle

@@ -100,6 +100,7 @@ dependencyVerification {
         'javax.inject:javax.inject:1:javax.inject-1.jar:91c77044a50c481636c32d916fd89c9118a72195390452c81065080f957de7ff',
         'javax.xml.bind:jaxb-api:2.2.12-b140109.1041:jaxb-api-2.2.12-b140109.1041.jar:b5e60cd8b7b5ff01ce4a74c5dd008f4fbd14ced3495d0b47b85cfedc182211f2',
         'junit:junit:4.12:junit-4.12.jar:59721f0805e223d84b90677887d9ff567dc534d7c502ca903c0c2b17f05c116a',
+        'moe.feng.support.biometricprompt:library:1.0.1:library-1.0.1.aar:2cf011abdc9c51a505b35f421197b4fbeba79af792e9ea1ca973f1aef087dacd',
         'nekohtml:nekohtml:1.9.6.2:nekohtml-1.9.6.2.jar:fdff6cfa9ed9cc911c842a5d2395f209ec621ef1239d46810e9e495809d3ae09',
         'nekohtml:xercesMinimal:1.9.6.2:xercesMinimal-1.9.6.2.jar:95b8b357d19f63797dd7d67622fd3f18374d64acbc6584faba1c7759a31e8438',
         'net.bytebuddy:byte-buddy-agent:1.7.9:byte-buddy-agent-1.7.9.jar:ac1a993befb528c3271a83a9ad9c42d363d399e9deb26e0470e3c4962066c550',