wtf

intercepting-communication/udp-2/.init

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+../.init

intercepting-communication/udp-2/DESCRIPTION.md

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+Though we didn't explore this for TCP, in addition to selecting the destination port, both TCP and UDP can set their _source_ port.
+We'll practice that here --- you can set the source port with `s.bind` on the socket, exactly how a server does it to set their listening port.

intercepting-communication/udp-2/run

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+#!/usr/bin/exec-suid --real -- /usr/bin/python -I
+
+import psutil
+import socket
+import os
+
+from dojjail import Host, Network
+
+flag = open("/flag").read()
+parent_process = psutil.Process(os.getppid())
+
+class ServerHost(Host):
+    def entrypoint(self):
+        server_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+        server_socket.bind(("0.0.0.0", 31337))
+        while True:
+            try:
+                client_message, (client_host, client_port) = server_socket.recvfrom(1024)
+                while True:
+                    if client_port != 31338:
+                        break
+                    if not client_message:
+                        break
+                    if client_message == b"Hello, World!\n":
+                        server_socket.sendto(flag.encode(), (client_host, client_port))
+                        break
+            except ConnectionError:
+                continue
+
+user_host = Host("ip-10-0-0-1", privileged_uid=parent_process.uids().effective)
+server_host = ServerHost("ip-10-0-0-2")
+network = Network(hosts={user_host: "10.0.0.1", server_host: "10.0.0.2"}, subnet="10.0.0.0/24")
+network.run()
+
+user_host.interactive(environ=parent_process.environ())