Allow simple use of keyboard-interactive authentication

[joshuaspence]

I am trying to use remote_file with an SSH server configured with:

PasswordAuthentication no
ChallengeResponseAuthentication yes
UsePAM yes

The challenge-response authentication is a simple password prompt, which is equivalent to PasswordAuthentication.

[tenstad]

Hi! Could you try to make this testable in the playground? I tried to use pam pwdfile, but did not get the challange 🤔

FROM ubuntu:latest

COPY key.pub /root/.ssh/authorized_keys

RUN apt-get update && apt-get install -y --no-install-recommends \
    apache2-utils \
    libpam-pwdfile \
    openssh-server \
    sudo \
    && rm -rf /var/lib/apt/lists/* \
    && mkdir /var/run/sshd \
    && ssh-keygen -A \
    && sed -i "s/#\?LogLevel.*/LogLevel DEBUG/" /etc/ssh/sshd_config \
    && sed -i "s/#\?PermitRootLogin.*/PermitRootLogin yes/" /etc/ssh/sshd_config \
    && echo "PasswordAuthentication yes" >> /etc/ssh/sshd_config \
    && echo "ChallengeResponseAuthentication yes" >> /etc/ssh/sshd_config \
    && echo "KbdInteractiveAuthentication yes" >> /etc/ssh/sshd_config \
    && sed -i "/@include common-auth/a auth        required    pam_pwdfile.so pwdfile=/pampwd" /etc/pam.d/sshd \
    && adduser --disabled-password bob \
    && echo "root:password" | chpasswd \
    && htpasswd -cdb /pampwd root password \
    && echo "bob:pwd" | chpasswd \
    && htpasswd -db /pampwd bob pwd \
    && chmod 600 /root/.ssh/authorized_keys

EXPOSE 22
CMD ["/usr/sbin/sshd", "-D", "-E", "/var/log/sshd"]