Encrypt logs before handing them to crash report process

bramble-android/src/main/java/org/briarproject/bramble/util/AndroidUtils.java

@@ -31,6 +31,7 @@ public class AndroidUtils {
 	private static final String FAKE_BLUETOOTH_ADDRESS = "02:00:00:00:00:00";
 
 	private static final String STORED_REPORTS = "dev-reports";
+	private static final String STORED_LOGCAT = "dev-logcat";
 
 	public static Collection<String> getSupportedArchitectures() {
 		List<String> abis = new ArrayList<>();
@@ -107,6 +108,10 @@ public class AndroidUtils {
 		return ctx.getDir(STORED_REPORTS, MODE_PRIVATE);
 	}
 
+	public static File getLogcatFile(Context ctx) {
+		return new File(ctx.getFilesDir(), STORED_LOGCAT);
+	}
+
 	/**
 	 * Returns an array of supported content types for image attachments.
 	 * GIFs can't be compressed on API < 24 so they're not supported.

bramble-api/src/main/java/org/briarproject/bramble/api/reporting/DevConfig.java

@@ -13,4 +13,6 @@ public interface DevConfig {
 	String getDevOnionAddress();
 
 	File getReportDir();
+
+	File getLogcatFile();
 }

briar-android/build.gradle

@@ -136,6 +136,7 @@ dependencies {
 	testImplementation "org.jmock:jmock:$jmockVersion"
 	testImplementation "org.jmock:jmock-junit4:$jmockVersion"
 	testImplementation "org.jmock:jmock-legacy:$jmockVersion"
+	testAnnotationProcessor "com.google.dagger:dagger-compiler:2.24"
 
 	androidTestImplementation project(path: ':bramble-api', configuration: 'testOutput')
 	androidTestImplementation 'androidx.test.ext:junit:1.1.2'

briar-android/src/main/java/org/briarproject/briar/android/AndroidComponent.java

@@ -34,6 +34,7 @@ import org.briarproject.briar.BriarCoreModule;
 import org.briarproject.briar.android.attachment.AttachmentModule;
 import org.briarproject.briar.android.attachment.media.MediaModule;
 import org.briarproject.briar.android.conversation.glide.BriarModelLoader;
+import org.briarproject.briar.android.logging.CachingLogHandler;
 import org.briarproject.briar.android.login.SignInReminderReceiver;
 import org.briarproject.briar.android.view.EmojiTextInputView;
 import org.briarproject.briar.api.android.AndroidNotificationManager;
@@ -179,6 +180,10 @@ public interface AndroidComponent
 
 	AndroidWakeLockManager wakeLockManager();
 
+	CachingLogHandler logHandler();
+
+	Thread.UncaughtExceptionHandler exceptionHandler();
+
 	void inject(SignInReminderReceiver briarService);
 
 	void inject(BriarService briarService);

briar-android/src/main/java/org/briarproject/briar/android/AppModule.java

@@ -33,12 +33,13 @@ import org.briarproject.briar.android.account.SetupModule;
 import org.briarproject.briar.android.contact.ContactListModule;
 import org.briarproject.briar.android.forum.ForumModule;
 import org.briarproject.briar.android.keyagreement.ContactExchangeModule;
+import org.briarproject.briar.android.logging.LoggingModule;
 import org.briarproject.briar.android.login.LoginModule;
 import org.briarproject.briar.android.navdrawer.NavDrawerModule;
 import org.briarproject.briar.android.privategroup.conversation.GroupConversationModule;
-import org.briarproject.briar.android.settings.SettingsModule;
 import org.briarproject.briar.android.privategroup.list.GroupListModule;
 import org.briarproject.briar.android.reporting.DevReportModule;
+import org.briarproject.briar.android.settings.SettingsModule;
 import org.briarproject.briar.android.sharing.SharingModule;
 import org.briarproject.briar.android.test.TestAvatarCreatorImpl;
 import org.briarproject.briar.android.viewmodel.ViewModelModule;
@@ -74,6 +75,7 @@ import static org.briarproject.briar.android.TestingConstants.IS_DEBUG_BUILD;
 		SetupModule.class,
 		DozeHelperModule.class,
 		ContactExchangeModule.class,
+		LoggingModule.class,
 		LoginModule.class,
 		NavDrawerModule.class,
 		ViewModelModule.class,
@@ -192,6 +194,11 @@ public class AppModule {
 			public File getReportDir() {
 				return AndroidUtils.getReportDir(app.getApplicationContext());
 			}
+
+			@Override
+			public File getLogcatFile() {
+				return AndroidUtils.getLogcatFile(app.getApplicationContext());
+			}
 		};
 		return devConfig;
 	}

briar-android/src/main/java/org/briarproject/briar/android/BriarApplication.java

@@ -6,9 +6,6 @@ import android.content.SharedPreferences;
 import org.briarproject.bramble.BrambleApplication;
 import org.briarproject.briar.android.navdrawer.NavDrawerActivity;
 
-import java.util.Collection;
-import java.util.logging.LogRecord;
-
 /**
  * This exists so that the Application object will not necessarily be cast
  * directly to the Briar application object.
@@ -17,8 +14,6 @@ public interface BriarApplication extends BrambleApplication {
 
 	Class<? extends Activity> ENTRY_ACTIVITY = NavDrawerActivity.class;
 
-	Collection<LogRecord> getRecentLogRecords();
-
 	AndroidComponent getApplicationComponent();
 
 	SharedPreferences getDefaultSharedPreferences();

briar-android/src/main/java/org/briarproject/briar/android/BriarApplicationImpl.java

@@ -20,12 +20,10 @@ import org.briarproject.bramble.BrambleCoreEagerSingletons;
 import org.briarproject.briar.BriarCoreEagerSingletons;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.logging.CachingLogHandler;
-import org.briarproject.briar.android.reporting.BriarExceptionHandler;
 import org.briarproject.briar.android.util.UiUtils;
 
-import java.util.Collection;
+import java.lang.Thread.UncaughtExceptionHandler;
 import java.util.logging.Handler;
-import java.util.logging.LogRecord;
 import java.util.logging.Logger;
 
 import androidx.annotation.NonNull;
@@ -42,16 +40,11 @@ public class BriarApplicationImpl extends Application
 	private static final Logger LOG =
 			getLogger(BriarApplicationImpl.class.getName());
 
-	private final CachingLogHandler logHandler = new CachingLogHandler();
-	private final BriarExceptionHandler exceptionHandler =
-			new BriarExceptionHandler(this);
-
 	private AndroidComponent applicationComponent;
 	private volatile SharedPreferences prefs;
 
 	@Override
 	protected void attachBaseContext(Context base) {
-		Thread.setDefaultUncaughtExceptionHandler(exceptionHandler);
 		if (prefs == null)
 			prefs = PreferenceManager.getDefaultSharedPreferences(base);
 		// Loading the language needs to be done here.
@@ -67,6 +60,11 @@ public class BriarApplicationImpl extends Application
 
 		if (IS_DEBUG_BUILD) enableStrictMode();
 
+		applicationComponent = createApplicationComponent();
+		UncaughtExceptionHandler exceptionHandler =
+				applicationComponent.exceptionHandler();
+		Thread.setDefaultUncaughtExceptionHandler(exceptionHandler);
+
 		Logger rootLogger = getLogger("");
 		Handler[] handlers = rootLogger.getHandlers();
 		// Disable the Android logger for release builds
@@ -78,12 +76,12 @@ public class BriarApplicationImpl extends Application
 			// Restore the default handlers after the level raising handler
 			for (Handler handler : handlers) rootLogger.addHandler(handler);
 		}
+		CachingLogHandler logHandler = applicationComponent.logHandler();
 		rootLogger.addHandler(logHandler);
 		rootLogger.setLevel(IS_DEBUG_BUILD ? FINE : INFO);
 
 		LOG.info("Created");
 
-		applicationComponent = createApplicationComponent();
 		EmojiManager.install(new GoogleEmojiProvider());
 	}
 
@@ -136,11 +134,6 @@ public class BriarApplicationImpl extends Application
 		return applicationComponent;
 	}
 
-	@Override
-	public Collection<LogRecord> getRecentLogRecords() {
-		return logHandler.getRecentLogRecords();
-	}
-
 	@Override
 	public AndroidComponent getApplicationComponent() {
 		return applicationComponent;

briar-android/src/main/java/org/briarproject/briar/android/logging/BriefLogFormatter.java

@@ -4,6 +4,7 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import java.text.DateFormat;
 import java.text.SimpleDateFormat;
+import java.util.Collection;
 import java.util.Date;
 import java.util.TimeZone;
 import java.util.logging.Formatter;
@@ -17,6 +18,16 @@ import static java.util.Locale.US;
 @NotNullByDefault
 public class BriefLogFormatter extends Formatter {
 
+	public static String formatLog(Formatter formatter,
+			Collection<LogRecord> logRecords) {
+		StringBuilder sb = new StringBuilder();
+		for (LogRecord record : logRecords) {
+			String formatted = formatter.format(record);
+			sb.append(formatted).append('\n');
+		}
+		return sb.toString();
+	}
+
 	private final Object lock = new Object();
 	private final DateFormat dateFormat; // Locking: lock
 	private final Date date; // Locking: lock

briar-android/src/main/java/org/briarproject/briar/android/logging/CachingLogHandler.java

@@ -21,6 +21,10 @@ public class CachingLogHandler extends Handler {
 	// Locking: lock
 	private final Queue<LogRecord> recent = new LinkedList<>();
 
+	// package-private constructor
+	CachingLogHandler() {
+	}
+
 	@Override
 	public void publish(LogRecord record) {
 		synchronized (lock) {

briar-android/src/main/java/org/briarproject/briar/android/logging/LogDecrypter.java

@@ -0,0 +1,16 @@
+package org.briarproject.briar.android.logging;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.util.AndroidUtils;
+
+import androidx.annotation.Nullable;
+
+@NotNullByDefault
+public interface LogDecrypter {
+	/**
+	 * Returns decrypted log records from {@link AndroidUtils#getLogcatFile}
+	 * or null if there was an error reading the logs.
+	 */
+	@Nullable
+	String decryptLogs(@Nullable byte[] logKey);
+}

briar-android/src/main/java/org/briarproject/briar/android/logging/LogDecrypterImpl.java

@@ -0,0 +1,61 @@
+package org.briarproject.briar.android.logging;
+
+import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.reporting.DevConfig;
+import org.briarproject.bramble.api.transport.StreamReaderFactory;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Scanner;
+import java.util.logging.Logger;
+
+import javax.inject.Inject;
+
+import androidx.annotation.Nullable;
+
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.util.LogUtils.logException;
+
+@NotNullByDefault
+class LogDecrypterImpl implements LogDecrypter {
+
+	private static final Logger LOG =
+			getLogger(LogDecrypterImpl.class.getName());
+
+	private final DevConfig devConfig;
+	private final StreamReaderFactory streamReaderFactory;
+
+	@Inject
+	LogDecrypterImpl(DevConfig devConfig,
+			StreamReaderFactory streamReaderFactory) {
+		this.devConfig = devConfig;
+		this.streamReaderFactory = streamReaderFactory;
+	}
+
+	@Nullable
+	@Override
+	public String decryptLogs(@Nullable byte[] logKey) {
+		if (logKey == null) return null;
+		SecretKey key = new SecretKey(logKey);
+		File logFile = devConfig.getLogcatFile();
+		try (InputStream in = new FileInputStream(logFile)) {
+			InputStream reader =
+					streamReaderFactory.createLogStreamReader(in, key);
+			Scanner s = new Scanner(reader);
+			StringBuilder sb = new StringBuilder();
+			while (s.hasNextLine()) sb.append(s.nextLine()).append("\n");
+			s.close();
+			return sb.toString();
+		} catch (IOException e) {
+			logException(LOG, WARNING, e);
+			return null;
+		} finally {
+			//noinspection ResultOfMethodCallIgnored
+			logFile.delete();
+		}
+	}
+}

briar-android/src/main/java/org/briarproject/briar/android/logging/LogEncrypter.java

@@ -0,0 +1,16 @@
+package org.briarproject.briar.android.logging;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.util.AndroidUtils;
+
+import androidx.annotation.Nullable;
+
+@NotNullByDefault
+public interface LogEncrypter {
+	/**
+	 * Writes encrypted log records to {@link AndroidUtils#getLogcatFile}
+	 * and returns the encryption key if everything went fine.
+	 */
+	@Nullable
+	byte[] encryptLogs();
+}

briar-android/src/main/java/org/briarproject/briar/android/logging/LogEncrypterImpl.java

@@ -0,0 +1,77 @@
+package org.briarproject.briar.android.logging;
+
+import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.reporting.DevConfig;
+import org.briarproject.bramble.api.transport.StreamWriter;
+import org.briarproject.bramble.api.transport.StreamWriterFactory;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.OutputStreamWriter;
+import java.io.Writer;
+import java.util.logging.Formatter;
+import java.util.logging.LogRecord;
+import java.util.logging.Logger;
+
+import javax.inject.Inject;
+
+import androidx.annotation.Nullable;
+
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.util.LogUtils.logException;
+
+@NotNullByDefault
+class LogEncrypterImpl implements LogEncrypter {
+
+	private static final Logger LOG =
+			getLogger(LogEncrypterImpl.class.getName());
+
+	private final DevConfig devConfig;
+	private final CachingLogHandler logHandler;
+	private final CryptoComponent crypto;
+	private final StreamWriterFactory streamWriterFactory;
+
+	@Inject
+	LogEncrypterImpl(DevConfig devConfig,
+			CachingLogHandler logHandler,
+			CryptoComponent crypto,
+			StreamWriterFactory streamWriterFactory) {
+		this.devConfig = devConfig;
+		this.logHandler = logHandler;
+		this.crypto = crypto;
+		this.streamWriterFactory = streamWriterFactory;
+	}
+
+	@Nullable
+	@Override
+	public byte[] encryptLogs() {
+		SecretKey logKey = crypto.generateSecretKey();
+		File logFile = devConfig.getLogcatFile();
+		try (OutputStream out = new FileOutputStream(logFile)) {
+			StreamWriter streamWriter =
+					streamWriterFactory.createLogStreamWriter(out, logKey);
+			Writer writer =
+					new OutputStreamWriter(streamWriter.getOutputStream());
+			writeLogString(writer);
+			writer.close();
+			return logKey.getBytes();
+		} catch (IOException e) {
+			logException(LOG, WARNING, e);
+			return null;
+		}
+	}
+
+	private void writeLogString(Writer writer) throws IOException {
+		Formatter formatter = new BriefLogFormatter();
+		for (LogRecord record : logHandler.getRecentLogRecords()) {
+			String formatted = formatter.format(record);
+			writer.append(formatted).append('\n');
+		}
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/logging/LoggingModule.java

@@ -0,0 +1,29 @@
+package org.briarproject.briar.android.logging;
+
+import javax.inject.Singleton;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public class LoggingModule {
+
+	@Provides
+	@Singleton
+	CachingLogHandler provideCachingLogHandler() {
+		return new CachingLogHandler();
+	}
+
+	@Provides
+	@Singleton
+	LogEncrypter provideLogEncrypter(LogEncrypterImpl logEncrypter) {
+		return logEncrypter;
+	}
+
+	@Provides
+	@Singleton
+	LogDecrypter provideLogDecrypter(LogDecrypterImpl logDecrypter) {
+		return logDecrypter;
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/reporting/BriarExceptionHandler.java

@@ -1,29 +1,40 @@
 package org.briarproject.briar.android.reporting;
 
-import android.content.Context;
+import android.app.Application;
 import android.os.Process;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.briar.android.logging.LogEncrypter;
 
 import java.lang.Thread.UncaughtExceptionHandler;
 
+import javax.inject.Inject;
+
 import static org.briarproject.briar.android.util.UiUtils.startDevReportActivity;
 
 @NotNullByDefault
-public class BriarExceptionHandler implements UncaughtExceptionHandler {
+class BriarExceptionHandler implements UncaughtExceptionHandler {
 
-	private final Context ctx;
+	private final Application app;
+	private final LogEncrypter logEncrypter;
 	private final long appStartTime;
 
-	public BriarExceptionHandler(Context ctx) {
-		this.ctx = ctx;
-		this.appStartTime = System.currentTimeMillis();
+	@Inject
+	BriarExceptionHandler(Application app, LogEncrypter logEncrypter) {
+		this.app = app;
+		this.logEncrypter = logEncrypter;
+		appStartTime = System.currentTimeMillis();
 	}
 
 	@Override
 	public void uncaughtException(Thread t, Throwable e) {
+		// encrypt logs to disk before handing over to new process
+		// the intent has limited space, so we can't reliably store them there.
+		byte[] logKey = logEncrypter.encryptLogs();
+
 		// activity runs in its own process, so we can kill the old one
-		startDevReportActivity(ctx, CrashReportActivity.class, e, appStartTime);
+		startDevReportActivity(app.getApplicationContext(),
+				CrashReportActivity.class, e, appStartTime, logKey);
 		Process.killProcess(Process.myPid());
 		System.exit(10);
 	}

briar-android/src/main/java/org/briarproject/briar/android/reporting/BriarReportCollector.java

@@ -25,8 +25,6 @@ import org.briarproject.bramble.api.Pair;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.briar.BuildConfig;
 import org.briarproject.briar.R;
-import org.briarproject.briar.android.BriarApplication;
-import org.briarproject.briar.android.logging.BriefLogFormatter;
 import org.briarproject.briar.android.reporting.ReportData.MultiReportInfo;
 import org.briarproject.briar.android.reporting.ReportData.ReportItem;
 import org.briarproject.briar.android.reporting.ReportData.SingleReportInfo;
@@ -41,8 +39,6 @@ import java.net.InetAddress;
 import java.net.UnknownHostException;
 import java.text.SimpleDateFormat;
 import java.util.Date;
-import java.util.logging.Formatter;
-import java.util.logging.LogRecord;
 
 import javax.annotation.concurrent.Immutable;
 
@@ -74,8 +70,8 @@ class BriarReportCollector {
 		this.ctx = ctx;
 	}
 
-	public ReportData collectReportData(@Nullable Throwable t,
-			long appStartTime) {
+	ReportData collectReportData(@Nullable Throwable t, long appStartTime,
+			String logs) {
 		ReportData reportData = new ReportData()
 				.add(getBasicInfo(t))
 				.add(getDeviceInfo());
@@ -86,7 +82,7 @@ class BriarReportCollector {
 				.add(getStorage())
 				.add(getConnectivity())
 				.add(getBuildConfig())
-				.add(getLogcat())
+				.add(getLogcat(logs))
 				.add(getDeviceFeatures());
 	}
 
@@ -313,15 +309,8 @@ class BriarReportCollector {
 				buildConfig);
 	}
 
-	private ReportItem getLogcat() {
-		BriarApplication app = (BriarApplication) ctx.getApplicationContext();
-		StringBuilder sb = new StringBuilder();
-		Formatter formatter = new BriefLogFormatter();
-		for (LogRecord record : app.getRecentLogRecords()) {
-			sb.append(formatter.format(record)).append('\n');
-		}
-		return new ReportItem("Logcat", R.string.dev_report_logcat,
-				sb.toString());
+	private ReportItem getLogcat(String logs) {
+		return new ReportItem("Logcat", R.string.dev_report_logcat, logs);
 	}
 
 	private ReportItem getDeviceFeatures() {

briar-android/src/main/java/org/briarproject/briar/android/reporting/CrashReportActivity.java

@@ -35,6 +35,7 @@ public class CrashReportActivity extends BaseActivity
 
 	public static final String EXTRA_THROWABLE = "throwable";
 	public static final String EXTRA_APP_START_TIME = "appStartTime";
+	public static final String EXTRA_APP_LOGCAT = "logcat";
 
 	@Inject
 	ViewModelProvider.Factory viewModelFactory;
@@ -56,7 +57,8 @@ public class CrashReportActivity extends BaseActivity
 		Intent intent = getIntent();
 		Throwable t = (Throwable) intent.getSerializableExtra(EXTRA_THROWABLE);
 		long appStartTime = intent.getLongExtra(EXTRA_APP_START_TIME, -1);
-		viewModel.init(t, appStartTime);
+		byte[] logKey = intent.getByteArrayExtra(EXTRA_APP_LOGCAT);
+		viewModel.init(t, appStartTime, logKey);
 		viewModel.getShowReport().observeEvent(this, show -> {
 			if (show) displayFragment(true);
 		});

briar-android/src/main/java/org/briarproject/briar/android/reporting/DevReportModule.java

@@ -15,4 +15,8 @@ public abstract class DevReportModule {
 	@ViewModelKey(ReportViewModel.class)
 	abstract ViewModel bindReportViewModel(ReportViewModel reportViewModel);
 
+	@Binds
+	abstract Thread.UncaughtExceptionHandler bindUncaughtExceptionHandler(
+			BriarExceptionHandler handler);
+
 }

briar-android/src/main/java/org/briarproject/briar/android/reporting/ReportViewModel.java

@@ -11,6 +11,9 @@ import org.briarproject.bramble.api.plugin.TorConstants;
 import org.briarproject.bramble.api.reporting.DevReporter;
 import org.briarproject.bramble.util.AndroidUtils;
 import org.briarproject.briar.R;
+import org.briarproject.briar.android.logging.BriefLogFormatter;
+import org.briarproject.briar.android.logging.CachingLogHandler;
+import org.briarproject.briar.android.logging.LogDecrypter;
 import org.briarproject.briar.android.reporting.ReportData.MultiReportInfo;
 import org.briarproject.briar.android.viewmodel.LiveEvent;
 import org.briarproject.briar.android.viewmodel.MutableLiveEvent;
@@ -19,6 +22,7 @@ import org.json.JSONException;
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.util.UUID;
+import java.util.logging.Formatter;
 import java.util.logging.Logger;
 
 import javax.inject.Inject;
@@ -36,13 +40,16 @@ import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.api.plugin.Plugin.State.ACTIVE;
 import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
+import static org.briarproject.briar.android.logging.BriefLogFormatter.formatLog;
 
 @NotNullByDefault
-public class ReportViewModel extends AndroidViewModel {
+class ReportViewModel extends AndroidViewModel {
 
 	private static final Logger LOG =
 			getLogger(ReportViewModel.class.getName());
 
+	private final CachingLogHandler logHandler;
+	private final LogDecrypter logDecrypter;
 	private final BriarReportCollector collector;
 	private final DevReporter reporter;
 	private final PluginManager pluginManager;
@@ -58,18 +65,39 @@ public class ReportViewModel extends AndroidViewModel {
 	private boolean isFeedback;
 
 	@Inject
-	public ReportViewModel(@NonNull Application application,
-			DevReporter reporter, PluginManager pluginManager) {
+	ReportViewModel(@NonNull Application application,
+			CachingLogHandler logHandler,
+			LogDecrypter logDecrypter,
+			DevReporter reporter,
+			PluginManager pluginManager) {
 		super(application);
-		this.collector = new BriarReportCollector(application);
+		collector = new BriarReportCollector(application);
+		this.logHandler = logHandler;
+		this.logDecrypter = logDecrypter;
 		this.reporter = reporter;
 		this.pluginManager = pluginManager;
 	}
 
-	void init(@Nullable Throwable t, long appStartTime) {
+	void init(@Nullable Throwable t, long appStartTime,
+			@Nullable byte[] logKey) {
 		isFeedback = t == null;
 		if (reportData.getValue() == null) new SingleShotAndroidExecutor(() -> {
-			ReportData data = collector.collectReportData(t, appStartTime);
+			String decryptedLogs;
+			if (isFeedback) {
+				Formatter formatter = new BriefLogFormatter();
+				decryptedLogs =
+						formatLog(formatter, logHandler.getRecentLogRecords());
+			} else {
+				decryptedLogs = logDecrypter.decryptLogs(logKey);
+				if (decryptedLogs == null) {
+					// error decrypting logs, get logs from this process
+					Formatter formatter = new BriefLogFormatter();
+					decryptedLogs = formatLog(formatter,
+							logHandler.getRecentLogRecords());
+				}
+			}
+			ReportData data =
+					collector.collectReportData(t, appStartTime, decryptedLogs);
 			reportData.postValue(data);
 		}).start();
 	}
@@ -110,8 +138,8 @@ public class ReportViewModel extends AndroidViewModel {
 	}
 
 	/**
-	 * The content of the report
-	 * that will be loaded after {@link #init(Throwable, long)} was called.
+	 * The content of the report that will be loaded after
+	 * {@link #init(Throwable, long, byte[])} was called.
 	 */
 	LiveData<ReportData> getReportData() {
 		return reportData;

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

@@ -97,6 +97,7 @@ import static java.util.concurrent.TimeUnit.DAYS;
 import static org.briarproject.bramble.util.AndroidUtils.getSupportedImageContentTypes;
 import static org.briarproject.briar.BuildConfig.APPLICATION_ID;
 import static org.briarproject.briar.android.TestingConstants.EXPIRY_DATE;
+import static org.briarproject.briar.android.reporting.CrashReportActivity.EXTRA_APP_LOGCAT;
 import static org.briarproject.briar.android.reporting.CrashReportActivity.EXTRA_APP_START_TIME;
 import static org.briarproject.briar.android.reporting.CrashReportActivity.EXTRA_THROWABLE;
 
@@ -357,16 +358,17 @@ public class UiUtils {
 	}
 
 	public static void triggerFeedback(Context ctx) {
-		startDevReportActivity(ctx, FeedbackActivity.class, null, null);
+		startDevReportActivity(ctx, FeedbackActivity.class, null, null, null);
 	}
 
 	public static void startDevReportActivity(Context ctx,
 			Class<? extends FragmentActivity> activity, @Nullable Throwable t,
-			@Nullable Long appStartTime) {
+			@Nullable Long appStartTime, @Nullable byte[] logKey) {
 		final Intent dialogIntent = new Intent(ctx, activity);
 		dialogIntent.setFlags(FLAG_ACTIVITY_NEW_TASK);
 		dialogIntent.putExtra(EXTRA_THROWABLE, t);
 		dialogIntent.putExtra(EXTRA_APP_START_TIME, appStartTime);
+		dialogIntent.putExtra(EXTRA_APP_LOGCAT, logKey);
 		ctx.startActivity(dialogIntent);
 	}
 

briar-android/src/test/java/org/briarproject/briar/android/logging/LogEncryptionDecryptionTest.java

@@ -0,0 +1,66 @@
+package org.briarproject.briar.android.logging;
+
+import org.briarproject.bramble.test.BrambleMockTestCase;
+import org.junit.ClassRule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+
+import java.io.IOException;
+import java.security.SecureRandom;
+import java.util.ArrayList;
+import java.util.logging.Level;
+import java.util.logging.LogRecord;
+
+import static java.util.logging.Level.FINE;
+import static java.util.logging.Level.INFO;
+import static java.util.logging.Level.SEVERE;
+import static java.util.logging.Level.WARNING;
+import static org.briarproject.bramble.util.StringUtils.getRandomString;
+import static org.briarproject.briar.android.logging.BriefLogFormatter.formatLog;
+import static org.junit.Assert.assertEquals;
+
+public class LogEncryptionDecryptionTest extends BrambleMockTestCase {
+
+	@ClassRule
+	public static TemporaryFolder folder = new TemporaryFolder();
+
+	private final SecureRandom random;
+	private final CachingLogHandler cachingLogHandler;
+	private final LogEncrypter logEncrypter;
+	private final LogDecrypter logDecrypter;
+	private final BriefLogFormatter logFormatter = new BriefLogFormatter();
+
+	public LogEncryptionDecryptionTest() throws IOException {
+		LoggingComponent loggingComponent = DaggerLoggingComponent.builder()
+				.loggingTestModule(new LoggingTestModule(folder.newFile()))
+				.build();
+		random = loggingComponent.random();
+		logEncrypter = loggingComponent.logEncrypter();
+		logDecrypter = loggingComponent.logDecrypter();
+		cachingLogHandler = loggingComponent.cachingLogHandler();
+	}
+
+	@Test
+	public void testEncryptedMatchesDecrypted() {
+		ArrayList<LogRecord> logRecords =
+				new ArrayList<>(random.nextInt(99) + 1);
+		for (int i = 0; i < logRecords.size(); i++) {
+			LogRecord logRecord = getRandomLogRecord();
+			cachingLogHandler.publish(logRecord);
+			logRecords.add(logRecord);
+		}
+		byte[] logKey = logEncrypter.encryptLogs();
+		assertEquals(formatLog(logFormatter, logRecords),
+				logDecrypter.decryptLogs(logKey));
+	}
+
+	private LogRecord getRandomLogRecord() {
+		Level[] levels = {SEVERE, WARNING, INFO, FINE};
+		Level level = levels[random.nextInt(levels.length)];
+		LogRecord logRecord =
+				new LogRecord(level, getRandomString(random.nextInt(128) + 1));
+		logRecord.setLoggerName(getRandomString(random.nextInt(23) + 1));
+		return logRecord;
+	}
+
+}

briar-android/src/test/java/org/briarproject/briar/android/logging/LoggingComponent.java

@@ -0,0 +1,29 @@
+package org.briarproject.briar.android.logging;
+
+import org.briarproject.bramble.BrambleCoreModule;
+import org.briarproject.bramble.test.TestSecureRandomModule;
+
+import java.security.SecureRandom;
+
+import javax.inject.Singleton;
+
+import dagger.Component;
+
+@Singleton
+@Component(modules = {
+		BrambleCoreModule.class,
+		TestSecureRandomModule.class,
+		LoggingModule.class,
+		LoggingTestModule.class,
+})
+public interface LoggingComponent {
+
+	SecureRandom random();
+
+	CachingLogHandler cachingLogHandler();
+
+	LogEncrypter logEncrypter();
+
+	LogDecrypter logDecrypter();
+
+}

briar-android/src/test/java/org/briarproject/briar/android/logging/LoggingTestModule.java

@@ -0,0 +1,52 @@
+package org.briarproject.briar.android.logging;
+
+import org.briarproject.bramble.api.crypto.PublicKey;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.reporting.DevConfig;
+
+import java.io.File;
+
+import javax.inject.Singleton;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+class LoggingTestModule {
+
+	private final File logFile;
+
+	LoggingTestModule(File logFile) {
+		this.logFile = logFile;
+	}
+
+	@Provides
+	@Singleton
+	DevConfig provideDevConfig() {
+		@NotNullByDefault
+		DevConfig devConfig = new DevConfig() {
+			@Override
+			public PublicKey getDevPublicKey() {
+				throw new UnsupportedOperationException();
+
+			}
+
+			@Override
+			public String getDevOnionAddress() {
+				throw new UnsupportedOperationException();
+			}
+
+			@Override
+			public File getReportDir() {
+				throw new UnsupportedOperationException();
+			}
+
+			@Override
+			public File getLogcatFile() {
+				return logFile;
+			}
+		};
+		return devConfig;
+	}
+
+}