ISA project 2022/2023

Tunneling of data transmissions via DNS queries

Author: Patrik Sehnoutek
Login: xsehno01
Date: 24.10.2022

Description

This project focuses on the implementation of an application for tunneling data through DNS queries. It implements client and server application.

Usage

• run everything in the root folder of the project

$ make

$ sudo ./dns_receiver {BASE_HOST} {DST_DIRPATH}
     
       {BASE_HOST}          is used to set the base domain to receive data
       {DST_DIRPATH}        path under which all incoming data/files will be saved (the path specified by the client will be created under this directory)

$ sudo ./dns_sender [-u UPSTREAM_DNS_IP] {BASE_HOST} {DST_FILEPATH} [SRC_FILEPATH]

       -u UPSTREAM_DNS_IP   is used to force a remote DNS server, default value: DNS server set in the system
       {BASE_HOST}          is used to set the base domain of all transfers, i.e. queries will be sent to addresses *.{BASE_HOST}
       {DST_FILEPATH}       path under which the data will be saved on server
       [SRC_FILEPATH]       path to the file that will be sent, if not specified applicaton reads data from STDIN

Usage examples

Open two terminals. You can run client application as many times as you want.

1. run server application

$ sudo ./dns_receiver example.com test-directory/

2. run client application

$ sudo -u 127.0.0.1 ./dns_sender example.com output-data.txt input-data.txt

$ sudo ./dns_sender example.com output-data.txt

Restrictions

• application doesn't support IPv6 protocol

List of uploaded files

• receiver/dns_receiver_events.c
• receiver/dns_receiver_events.h
• sender/dns_sender_events.c
• sender/dns_sender_events.h
• base32.c
• base32.h
• dns.h
• error.h
• Makefile
• README.md
• manual.pdf