Merge branch 'tor-snowflake' into 'master'

tor-over-snowflake

Closes #9045

See merge request leap/bitmask_android!138

1 files changed, 178 insertions, 0 deletions

diff --git a/app/src/main/java/se/leap/bitmaskclient/tor/ClientTransportPlugin.java b/app/src/main/java/se/leap/bitmaskclient/tor/ClientTransportPlugin.java
new file mode 100644
index 00000000..764d5f06
--- /dev/null
+++ b/app/src/main/java/se/leap/bitmaskclient/tor/ClientTransportPlugin.java
@@ -0,0 +1,178 @@
+package se.leap.bitmaskclient.tor;
+/**
+ * Copyright (c) 2021 LEAP Encryption Access Project and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+import android.content.Context;
+import android.os.FileObserver;
+import android.util.Log;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import org.torproject.jni.ClientTransportPluginInterface;
+
+import java.io.BufferedReader;
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.lang.ref.WeakReference;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.Scanner;
+import java.util.Vector;
+import java.util.concurrent.TimeoutException;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import IPtProxy.IPtProxy;
+
+public class ClientTransportPlugin implements ClientTransportPluginInterface {
+    public static String TAG = ClientTransportPlugin.class.getSimpleName();
+
+    private HashMap<String, String> mFronts;
+    private final WeakReference<Context> contextRef;
+    private long snowflakePort = -1;
+    private FileObserver logFileObserver;
+    private static final Pattern SNOWFLAKE_LOG_TIMESTAMP_PATTERN = Pattern.compile("((19|2[0-9])[0-9]{2}\\/\\d{1,2}\\/\\d{1,2} \\d{1,2}:\\d{1,2}:\\d{1,2}) ([\\S|\\s]+)");
+
+    public ClientTransportPlugin(Context context) {
+        this.contextRef = new WeakReference<>(context);
+        loadCdnFronts(context);
+    }
+
+    @Override
+    public void start() {
+        Context context = contextRef.get();
+        if (context == null) {
+            return;
+        }
+        File logfile = new File(context.getApplicationContext().getCacheDir(), "snowflake.log");
+        Log.d(TAG, "logfile at " + logfile.getAbsolutePath());
+        try {
+            if (logfile.exists()) {
+                logfile.delete();
+            }
+            logfile.createNewFile();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+
+        //this is using the current, default Tor snowflake infrastructure
+        String target = getCdnFront("snowflake-target");
+        String front = getCdnFront("snowflake-front");
+        String stunServer = getCdnFront("snowflake-stun");
+        Log.d(TAG, "startSnowflake. target: " + target + ", front:" + front + ", stunServer" + stunServer);
+        snowflakePort = IPtProxy.startSnowflake( stunServer, target, front, logfile.getAbsolutePath(), false, false, true, 5);
+        Log.d(TAG, "startSnowflake running on port: " + snowflakePort);
+        watchLogFile(logfile);
+    }
+
+    private void watchLogFile(File logfile) {
+        final Vector<String> lastBuffer = new Vector<>();
+        logFileObserver = new FileObserver(logfile.getAbsolutePath()) {
+            @Override
+            public void onEvent(int event, @Nullable String name) {
+                if (FileObserver.MODIFY == event) {
+                    try (Scanner scanner = new Scanner(logfile)) {
+                        Vector<String> currentBuffer = new Vector<>();
+                        while (scanner.hasNextLine()) {
+                            currentBuffer.add(scanner.nextLine());
+                        }
+                        if (lastBuffer.size() < currentBuffer.size()) {
+                            int startIndex =  lastBuffer.size() > 0 ? lastBuffer.size() - 1 : 0;
+                            int endIndex = currentBuffer.size() - 1;
+                            Collection<String> newMessages = currentBuffer.subList(startIndex, endIndex);
+                            for (String message : newMessages) {
+                                logSnowflakeMessage(message);
+                            }
+                            lastBuffer.addAll(newMessages);
+                        }
+                    } catch (FileNotFoundException e) {
+                        e.printStackTrace();
+                    }
+                }
+            }
+        };
+        logFileObserver.startWatching();
+    }
+
+    @Override
+    public void stop() {
+        IPtProxy.stopSnowflake();
+         try {
+            TorStatusObservable.waitUntil(this::isSnowflakeOff, 10);
+        } catch (InterruptedException | TimeoutException e) {
+            e.printStackTrace();
+        }
+        snowflakePort = -1;
+        logFileObserver.stopWatching();
+    }
+
+    private boolean isSnowflakeOff() {
+        return TorStatusObservable.getSnowflakeStatus() == TorStatusObservable.SnowflakeStatus.OFF;
+    }
+
+    @Override
+    public String getTorrc() {
+        return "UseBridges 1\n" +
+                "ClientTransportPlugin snowflake socks5 127.0.0.1:" + snowflakePort + "\n" +
+                "Bridge snowflake 192.0.2.3:1";
+    }
+
+    private void loadCdnFronts(Context context) {
+        if (mFronts == null) {
+            mFronts = new HashMap<>();
+        }
+        try {
+            BufferedReader reader = new BufferedReader(new InputStreamReader(context.getAssets().open("fronts")));
+            String line;
+            while (true) {
+                line = reader.readLine();
+                if (line == null) break;
+                String[] front = line.split(" ");
+                mFronts.put(front[0], front[1]);
+                Log.d(TAG, "front: " + front[0] + ", " + front[1]);
+            }
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+
+    @Nullable
+    private String getCdnFront(String service) {
+        if (mFronts != null) {
+            return mFronts.get(service);
+        }
+        return null;
+    }
+
+    private void logSnowflakeMessage(String message) {
+        Matcher matcher = SNOWFLAKE_LOG_TIMESTAMP_PATTERN.matcher(message);
+        if (matcher.matches()) {
+            try {
+                String strippedString = matcher.group(3).trim();
+                if (strippedString.length() > 0) {
+                    TorStatusObservable.logSnowflakeMessage(contextRef.get(), strippedString);
+                }
+            } catch (IndexOutOfBoundsException | IllegalStateException e) {
+                e.printStackTrace();
+            }
+        } else {
+            TorStatusObservable.logSnowflakeMessage(contextRef.get(), message);
+        }
+    }
+}