Dockerfile with LD_PRELOAD

Dockerfile

FROM ubuntu:18.04

RUN DEBIAN_FRONTEND=noninteractive apt-get update -y && apt-get install -y \
    socat \
&& rm -rf /var/lib/apt/lists/*

RUN useradd -m my-challenge

WORKDIR /home/my-challenge

COPY my-challenge
COPY libc.so.6 .
COPY ld-2.27.so .
COPY flag .
RUN chown -R root:my-challenge /home/my-challenge && \
    chmod -R 750 /home/my-challenge && \
    chmod 740 /home/my-challenge/flag

EXPOSE 4444
USER my-challenge
CMD while true; do \
        socat TCP-LISTEN:4444,reuseaddr,fork EXEC:"env LD_PRELOAD=./libc.so.6 ./ld-2.27.so ./my-challenge",stderr; \
    done