From 5afdb3d3ed61efd547b3756e5c1c4f119e126500 Mon Sep 17 00:00:00 2001
From: cyBerta <cyberta@riseup.net>
Date: Mon, 27 Jun 2022 23:06:09 +0200
Subject: allow to pin a custom obfs4 bridge during compile time

---
 app/build.gradle                                    |  2 ++
 .../openvpn/core/connection/Obfs4Connection.java    |  5 +++--
 .../leap/bitmaskclient/eip/VpnConfigGenerator.java  | 21 +++++++++++++++++----
 .../pluggableTransports/Obfs4Options.java           |  1 +
 4 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/app/build.gradle b/app/build.gradle
index 73dfcc0c..3e4f4ee2 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -50,6 +50,7 @@ android {
     buildConfigField "String", "obfsvpn_port", '""'
     buildConfigField "String", "obfsvpn_ip", '""'
     buildConfigField "String", "obfsvpn_cert", '""'
+    buildConfigField 'boolean', 'obfsvpn_use_kcp', 'false'
 
     // static update url pointing to the latest stable release apk
     buildConfigField "String", "update_apk_url", '"https://dl.bitmask.net/client/android/Bitmask-Android-latest.apk"'
@@ -147,6 +148,7 @@ android {
       buildConfigField "String", "obfsvpn_port", '""'
       buildConfigField "String", "obfsvpn_ip", '""'
       buildConfigField "String", "obfsvpn_cert", '""'
+      buildConfigField 'boolean', 'obfsvpn_use_kcp', 'false'
 
       //Build Config Fields for automatic apk update checks
 
diff --git a/app/src/main/java/de/blinkt/openvpn/core/connection/Obfs4Connection.java b/app/src/main/java/de/blinkt/openvpn/core/connection/Obfs4Connection.java
index 393afd94..7cfe4988 100644
--- a/app/src/main/java/de/blinkt/openvpn/core/connection/Obfs4Connection.java
+++ b/app/src/main/java/de/blinkt/openvpn/core/connection/Obfs4Connection.java
@@ -19,20 +19,21 @@ public class Obfs4Connection extends Connection {
 
     public Obfs4Connection(Obfs4Options options) {
         if (BuildConfig.use_obfsvpn) {
-            setUseUdp(options.udp);
             setServerName(options.remoteIP);
             setServerPort(options.remotePort);
             setProxyName(ObfsVpnClient.SOCKS_IP);
             setProxyPort(ObfsVpnClient.SOCKS_PORT);
             setProxyType(ProxyType.SOCKS5);
         } else {
-            setUseUdp(false);
             setServerName(DISPATCHER_IP);
             setServerPort(DISPATCHER_PORT);
             setProxyName("");
             setProxyPort("");
             setProxyType(ProxyType.NONE);
         }
+        // while udp/kcp might be used on the wire,
+        // we don't use udp for openvpn in case of a obfs4 connection
+        setUseUdp(false);
         setProxyAuthUser(null);
         setProxyAuthPassword(null);
         setUseProxyAuth(false);
diff --git a/app/src/main/java/se/leap/bitmaskclient/eip/VpnConfigGenerator.java b/app/src/main/java/se/leap/bitmaskclient/eip/VpnConfigGenerator.java
index 061c1aa3..695e3b50 100644
--- a/app/src/main/java/se/leap/bitmaskclient/eip/VpnConfigGenerator.java
+++ b/app/src/main/java/se/leap/bitmaskclient/eip/VpnConfigGenerator.java
@@ -56,6 +56,8 @@ import static se.leap.bitmaskclient.pluggableTransports.ObfsVpnClient.SOCKS_PORT
 import static se.leap.bitmaskclient.pluggableTransports.Shapeshifter.DISPATCHER_IP;
 import static se.leap.bitmaskclient.pluggableTransports.Shapeshifter.DISPATCHER_PORT;
 
+import android.os.Build;
+
 public class VpnConfigGenerator {
     private JSONObject generalConfiguration;
     private JSONObject gateway;
@@ -144,7 +146,15 @@ public class VpnConfigGenerator {
         String cert = transportOptions.getString("cert");
         String port = obfs4Transport.getJSONArray(PORTS).getString(0);
         String ip = gateway.getString(IP_ADDRESS);
-        return new Obfs4Options(ip, port, cert, iatMode, false);
+        boolean udp = false;
+
+        if (BuildConfig.obfsvpn_pinning) {
+            cert = BuildConfig.obfsvpn_cert;
+            port = BuildConfig.obfsvpn_port;
+            ip = BuildConfig.obfsvpn_port;
+            udp = BuildConfig.obfsvpn_use_kcp;
+        }
+        return new Obfs4Options(ip, port, cert, iatMode, udp);
     }
 
     private String generalConfiguration() {
@@ -334,10 +344,13 @@ public class VpnConfigGenerator {
         String route = "route " + ipAddress + " 255.255.255.255 net_gateway" + newLine;
         stringBuilder.append(route);
         if (BuildConfig.use_obfsvpn) {
-            String proxy = SOCKS_PROXY + " " + SOCKS_IP + " " + SOCKS_PORT + newLine;
-            stringBuilder.append(proxy);
+            String remote;
+            if (BuildConfig.obfsvpn_pinning) {
+                remote = REMOTE + " " + BuildConfig.obfsvpn_ip + " " + BuildConfig.obfsvpn_port + newLine;
+            } else {
+                remote = REMOTE + " " + ipAddress + " " + ports.getString(0) + newLine;
+            }
 
-            String remote = REMOTE + " " + ipAddress + " " + ports.getString(0) + newLine;
             stringBuilder.append(remote);
         } else {
             String remote = REMOTE + " " + DISPATCHER_IP + " " + DISPATCHER_PORT + " tcp" + newLine;
diff --git a/app/src/main/java/se/leap/bitmaskclient/pluggableTransports/Obfs4Options.java b/app/src/main/java/se/leap/bitmaskclient/pluggableTransports/Obfs4Options.java
index ab6ea445..b96f88ca 100644
--- a/app/src/main/java/se/leap/bitmaskclient/pluggableTransports/Obfs4Options.java
+++ b/app/src/main/java/se/leap/bitmaskclient/pluggableTransports/Obfs4Options.java
@@ -7,6 +7,7 @@ public class Obfs4Options implements Serializable {
     public String iatMode;
     public String remoteIP;
     public String remotePort;
+    // openvpn is still using tcp, obfs4 is wrapped in kcp, if udp == true
     public boolean udp;
 
     public Obfs4Options(String remoteIP, String remotePort, String cert, String iatMode, boolean udp) {
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