Dockerfile for CTF

Dockerfile

FROM ubuntu:18.04

ENV DEBIAN_FRONTEND=noninteractive

RUN apt update && apt install xinetd libc6-dev-i386 -y
RUN useradd -mU user
COPY ./flag /home/user
COPY ./prob /home/user
COPY ./xinetd.d /etc/xinetd.d/prob
RUN chmod 750 /home/user /home/user/prob
RUN chmod 440 /home/user/flag
RUN chown -R root:user /home/user
CMD ["/usr/sbin/xinetd", "-dontfork"]

 

docker-compose.yml

version: '3'

services:
    prob:
        build:
            context: .
            dockerfile: ./dockerfile
        ports:
            - "7777:7777"

 

xinetd.d

service prob
{
    disable     = no
    type        = UNLISTED
    wait        = no
    server      = /home/user/prob
    socket_type = stream
    protocol    = tcp
    user        = user
    port        = 7777
    flags       = REUSE
}

 

docker-compose up -d