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@fopina
Created September 3, 2021 01:01
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onion-pi setup (reversed, WiFi as WAN)

Walkthrough to setup a raspberry pi as an onion router. Pretty much like onion-pi but WiFi as WAN instead (bonus: no hostapd required).

As a Pi0w or a Pi1 can easily be powered by the laptop USB, this setup makes a TOR-WiFi (bulky) dongle out of a Pi!!

This should (will?) be converted into an ansible playbook (or even pre-cooked image)

SDCard

  • Download latest raspios
  • Dump it on an sd card, eg:
    sudo dd if=2021-05-07-raspios-buster-armhf-lite.img of=/dev/rdisk2 bs=1m
    
  • Mount the boot partition of the sd card (if it isn't already) and;
    • create ssh empty file to enable ssh on boot
    • create wpa_supplicant.conf to connect to your local WiFi on boot, eg:
      ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
      network={
          ssid="myHome"
          psk="mynetworkpassword"
          key_mgmt=WPA-PSK
      }
      
  • Unmount, plug it in the Pi and boot it. If DHCP hostname resolution is working, raspberrypi should resolve to its IP, otherwise just portscan the network on 22 :)

Setup

This all go into a session of ssh pi@raspberrypi (with default password of raspberry) and sudo -s

  • Change pi password (or create a whole new user - onion?)
  • Change hostname (update /etc/hosts and /etc/hostname)
  • Uninstall or disable services that are useless for this
    systemctl disable triggerhappy alsa-state avahi-daemon avahi-daemon.socket
    
  • Install tor apt install -y tor
  • Edit /etc/tor/torc and add these lines on top
    Log notice file /var/log/tor/notices.log
    VirtualAddrNetwork 10.192.0.0/10
    AutomapHostsSuffixes .onion,.exit
    AutomapHostsOnResolve 1
    TransPort 192.168.42.1:9040
    DNSPort 192.168.42.1:53
    
  • Set up iptables
    iptables -F
    iptables -t nat -F
    iptables -t nat -A PREROUTING -i eth0 -p udp --dport 53 -j REDIRECT --to-ports 53
    iptables -t nat -A PREROUTING -i eth0 -p tcp --syn -j REDIRECT --to-ports 9040
    
  • Save rules
    apt install -y iptables-persistent
    iptables-save > /etc/iptables/rules.v4
    
  • Set static IP on eth0, by adding these lines to /etc/dhcpcd.conf
    interface eth0
    static ip_address=192.168.42.1/24
    
  • Setup DHCP server (or not, if you don't mind the extra work for reasonable doubt)
    • Install
      apt install -y isc-dhcp-server
      
    • Bind server to eth0 - edit /etc/default/isc-dhcp-server and set these values:
    INTERFACESv4="eth0"
    INTERFACESv6=""
    
    • Setup subnet in /etc/dhcp/dhcpd.conf
    subnet 192.168.42.0 netmask 255.255.255.224 {
      range 192.168.42.10 192.168.42.20;
      option routers 192.168.42.1;
      option domain-name-servers 192.168.42.1;
    }
    

Issues

Static IP with dhcpcd5 sucks: it only sets the IP once cable is plugged yet TOR requires IP to be set in order to bind to it - MAKE SURE you always connect the ethernet cable to the powered laptop before turning on the Pi...

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