name: Run Collaborative CTF Environment

on:

workflow_dispatch:

inputs:

ngrok_token:

description: Token to use for ngrok (optional)

required: false

additional_packages:

description: Install CTF packages

required: true

type: boolean

default: true

jobs:

start_server:

name: Set up and start the collaborative CTF server

runs-on: ubuntu-20.04

steps:

- name: Install base packages

run: |

# Fix certificate issue with pyopenssl

python3 -m pip install --upgrade pip setuptools wheel pyopenssl

python -m pip install --upgrade pip setuptools wheel pyopenssl

sudo apt-get update

# NOTE: upgrading takes way too long, and doesn't seem totally

# necessary; hence it has been commented out

# sudo apt-get --yes upgrade

# NOTE: many of these are already installed; included for posterity

# TODO: add other packages for CTF stuff

PACKAGES=(

binutils

curl

wget

gcc

tmux

neovim

)

sudo apt-get --yes install ${PACKAGES[@]}

- name: Install additional packages

if: ${{ inputs.additional_packages }}

run: |

# NOTE: many of these are already installed; included for posterity

# TODO: add other packages for CTF stuff

PACKAGES=(

nmap

htop

gdb

netcat

socat

build-essential

imagemagick

jq

binwalk

exiftool

hashcat

qemu

valgrind

)

sudo apt-get --yes install ${PACKAGES[@]}

PIP_PACKAGES=(

pwntools

ciphey

ofrak

)

python3 -m pip install --upgrade ${PIP_PACKAGES[@]}

# Install pup, not available on apt

mkdir -p ~/Downloads;

cd ~/Downloads;

wget \

--output-document pup_v0.4.0_linux_amd64.zip \

"https://github.com/ericchiang/pup/releases/download/v0.4.0/pup_v0.4.0_linux_amd64.zip";

unzip pup_v0.4.0_linux_amd64.zip;

sudo mv ./pup /usr/local/bin/pup;

# Make CTF files from the repo available in the ~/ctf directory

- uses: actions/checkout@v2

- name: Move checked out repository to ~/ctf

run: |

cd

mv "$GITHUB_WORKSPACE" ~/ctf

# Re-create the workspace directory, otherwise subsequent steps start

# in a folder that doesn't exist and immediately fail

mkdir --parents "$GITHUB_WORKSPACE"

- name: Install dotfiles

run: |

cd ~/ctf/dotfiles

bash install.sh

cp ./ttyd_run.sh ~/ttyd_run.sh

cp ./ngrok.yml ~/ngrok.yml

# Change the runner password to "ctf"; by default it has no password,

# which complicates some things like connecting via SSH

echo "runner:ctf" | sudo chpasswd

# Add a command to kill the action by killing the "sleep" process

echo 'alias quit="pkill sleep"' >> ~/.bashrc

- name: Install ngrok and run in the background as a daemon

run: |

# Only proceed if there is a user-supplied authtoken for ngrok.

# Prefer one submitted with a workflow dispatch, but accept one

# stored as a repository secret.

NGROK_AUTHTOKEN="${{ github.event.inputs.ngrok_token }}"

if [ -z "$NGROK_AUTHTOKEN" ]; then

NGROK_AUTHTOKEN="${{ secrets.NGROK_TOKEN }}"

fi

if [ -z "$NGROK_AUTHTOKEN" ]; then

exit 0

fi

# Add the authtoken to the ngrok configuration file

echo "authtoken: $NGROK_AUTHTOKEN" >> ~/ngrok.yml

# Download and install ngrok

cd

wget \

--quiet \

--output-document ngrok.zip \

"https://bin.equinox.io/c/4VmDzA7iaHb/ngrok-stable-linux-amd64.zip"

unzip ngrok.zip

sudo mv ngrok /usr/local/bin/ngrok

touch ~/ngrok.log

# Run ngrok in the background as a daemon

start-stop-daemon \

--start \

--background \

--chdir ~/ctf \

--exec /usr/local/bin/ngrok \

-- \

start \

-config ~/ngrok.yml \

ttyd ssh

- name: Install ttyd and run in the background as a daemon

run: |

# xterm is required for tmux/ttyd. Installed here to highlight that

# this is the specific part of the script that requires it.

sudo apt-get --yes install xterm

# Download and install ttyd

cd

wget \

--quiet \

--output-document ttyd \

"https://github.com/tsl0922/ttyd/releases/download/1.6.1/ttyd_linux.x86_64"

chmod +x ttyd

sudo mv ttyd /usr/local/bin/ttyd

# Run ttyd in the background as a daemon

start-stop-daemon \

--start \

--background \

--chdir ~/ctf \

--exec /usr/local/bin/ttyd \

-- \

--port 7681 \

--credential runner:ctf \

/bin/bash ~/ttyd_run.sh

- name: Install Tor and run a hidden service in the background as a daemon

run: |

sudo apt-get --yes install tor

# Sometimes it's already running for some reason...?

sudo service tor stop

sudo killall tor || true

# Generate a random port for Tor to use since the default is often

# taken

export TOR_SOCKS_PORT="$((1025 + RANDOM % 8975))"

# Run a hidden service in the background as a daemon -- allow

# connecting to the ttyd instance via a browser and allow SSH

tor \

--runasdaemon 1 \

--socksport $TOR_SOCKS_PORT \

--hiddenservicedir /home/runner/tor_service \

--hiddenserviceport "80 127.0.0.1:7681" \

--hiddenserviceport "22 127.0.0.1:22"

- name: Install PyJam and create a tunnel in the background

run: |

sudo apt-get install -y wireguard

curl https://tunnel.pyjam.as/7681 > /tmp/7681.conf

wg-quick up /tmp/7681.conf

- name: Display connection information

run: |

# Start a tmux session in the background whose window group everyone

# will share

tmux new-session -d -c ~/ctf -s ctf

echo Waiting for things to start up...

sleep 20s

echo

echo When connecting, use username "'runner'" and password "'ctf'"

echo

# Print Tor connection info

echo To connect securely over Tor:

printf "http://%s\n" "$(cat ~/tor_service/hostname)"

printf \

"ssh -o ProxyCommand='nc -x localhost:9150 %%h %%p' ssh://runner@%s\n\n" \

"$(cat ~/tor_service/hostname)"

# Print ngrok connection info (if applicable)

NGROK_AUTHTOKEN="${{ github.event.inputs.ngrok_token }}"

if [ -z "$NGROK_AUTHTOKEN" ]; then

NGROK_AUTHTOKEN="${{ secrets.NGROK_TOKEN }}"

fi

if [ -n "$NGROK_AUTHTOKEN" ]; then

echo "To connect using ngrok (i.e., not Tor):"

cat ~/ngrok.log \

| jq .url \

| grep -v "null" \

| tr -d '"' \

| sed 's/tcp:\/\/\(.*\)/ssh ssh:\/\/runner@\1/g' \

| sort

fi

echo 'To connect via PyJam (over HTTPS):'

cat /tmp/7681.conf \

| grep https \

| sed 's/.*\(https:\/\/[^ ]*\).*/\1/g'

- name: Wait...

run: |

# Wait... This process will be killed to end the Action. Return a

# non-failure exit code in any case so that there are no unnecessary

# notifications about a failed Actions workflow.

sleep 6h || true

- name: Clean up

run: |

echo Done!