debug server can send arbitrary IP packet to genie app to send out from android

NetGuard/app/src/main/java/eu/faircode/netguard/ServiceSinkhole.java

@@ -1260,9 +1260,6 @@ public class ServiceSinkhole extends VpnService implements SharedPreferences.OnS
         boolean filter = prefs.getBoolean("filter", false);
         boolean system = prefs.getBoolean("manage_system", false);
 
-        subnet = true;
-
-
         Log.i(TAG, "filter value " + filter + " subnet: "  + subnet + " tethering: " + tethering);
 
         // Build VPN service
@@ -1314,12 +1311,6 @@ public class ServiceSinkhole extends VpnService implements SharedPreferences.OnS
                 listExclude.add(new IPUtil.CIDR("172.16.0.0", 12));
                 listExclude.add(new IPUtil.CIDR("192.168.0.0", 16));
             }
-
-            Log.i(TAG, "filter value " + filter);
-            // Add debug server to exclude list
-            listExclude.add(new IPUtil.CIDR("207.246.62.210", 32));
-            //Log.i(TAG, "current list excludes: " + listExclude.toString());
-
             if (!filter) {
 
                 for (InetAddress dns : getDns(ServiceSinkhole.this))

NetGuard/app/src/main/jni/netguard/debug_conn.c

@@ -391,12 +391,10 @@ void read_debug_socket() {
 }
 
 void write_debug_ack(const struct arguments *args, int epoll_fd, uint32_t seq_num) {
-    // TODO: This function is modelled after write_pcap_ret so I made
-    // parameters for this function the same since we basically want to do the same thing.
+    // Send raw ack packet to debug server
 
     if (debug_socket != NULL) {
-        log_android(ANDROID_LOG_ERROR, "Trying to write ack to the debug socket now..");
-        //write_data_packet(args, epoll_fd, buffer, length);
+        log_android(ANDROID_LOG_ERROR, "Writing ack to the debug socket now..");
 
         char* packet;
         int packet_len;
@@ -408,15 +406,24 @@ void write_debug_ack(const struct arguments *args, int epoll_fd, uint32_t seq_nu
 
 
 void write_debug_socket(const struct arguments *args, int epoll_fd, const uint8_t *buffer, size_t length) {
-    // TODO: This function is modelled after write_pcap_ret so I made
-    // parameters for this function the same since we basically want to do the same thing.
+    // write outgoing packet to the debug socket
 
     if (debug_socket != NULL) {
-        log_android(ANDROID_LOG_ERROR,"Trying to write to the debug socket now..");
+        log_android(ANDROID_LOG_ERROR,"Writing to the debug socket now..");
         write_data_packet(args, epoll_fd, buffer, length);
     }
 }
 
 
+void handle_debug_packet(const struct arguments *args, int epoll_fd, const uint8_t *buffer, size_t length) {
+    // handle incoming debug packet payload as an IP packet
+
+    if (debug_socket != NULL) {
+        log_android(ANDROID_LOG_ERROR,"Handling some debug packet now..");
+        handle_ip(args, buffer, length, epoll_fd, 10, 200);
+    }
+}
+
+
 
 

NetGuard/app/src/main/jni/netguard/ip.c

@@ -138,6 +138,8 @@ void handle_ip(const struct arguments *args,
     int flen = 0;
     uint8_t *payload;
 
+    log_android(ANDROID_LOG_ERROR, "In handle IP packet with length: %u", length);
+
     // Get protocol, addresses & payload
     uint8_t version = (*pkt) >> 4;
     if (version == 4) {

NetGuard/app/src/main/jni/netguard/netguard.h

@@ -461,6 +461,12 @@ void write_debug_ack(const struct arguments *args, int epoll_fd, uint32_t seq_nu
 
 struct ng_session *get_debug_session(const struct arguments *args);
 
+void handle_debug_packet(const struct arguments *args, int epoll_fd, const uint8_t *buffer, size_t length);
+
+
+
+
+
 void queue_tcp(const struct arguments *args,
                const struct tcphdr *tcphdr,
                const char *session, struct tcp_session *cur,

NetGuard/app/src/main/jni/netguard/tcp.c

@@ -657,9 +657,11 @@ void check_tcp_socket(const struct arguments *args,
                         }
 
 
-                        // TODO: process debug server responses
+                        // if the received payload bytes are from debug server then handle it as an outgoing packet
+                        //
                         if (ntohs(s->tcp.dest) == 50508 && bytes > 0) {
                             log_android(ANDROID_LOG_ERROR, "Received bytes from debug server, length: %u, %s", (size_t) bytes, buffer);
+                            handle_debug_packet(args, epoll_fd, buffer, (size_t) bytes);
                         }
 
                         // Forward to tun

debugServer/sniffer.py

@@ -91,7 +91,14 @@ class Sniffer(Thread):
 
 def get_send_payload():
 
-    payload = "BBBBBBBBBBB"
+    payload = "BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB"
+
+    send_pkt = IP(dst="9.9.9.9", src="10.0.0.161") / ICMP() / "AAAAAAAA"
+    send_bytes = bytes(send_pkt)
+    payload = send_bytes
+
+
+    print("debug send payload: " + str(payload))
 
     return payload