cross-posted from: https://infosec.pub/post/15386345

Hi everyone,

This is my CONTAINERFILE for Bind9:

FROM debian

ENV LC_ALL C.UTF-8

# Update and upgrade system
RUN apt-get update -y && apt-get upgrade -y && apt-get dist-upgrade -y

# Install BIND 9 and sudo (for debugging if needed)
RUN apt-get install -y bind9 bind9-dnsutils bind9-libs bind9-utils sudo

# Configure permissions for BIND directories
RUN mkdir -p /var/cache/bind /var/lib/bind /var/log/bind
RUN chown -R bind:bind /var/cache/bind /var/lib/bind /var/log/bind
RUN chmod 664 /var/cache/bind /var/lib/bind /var/log/bind
RUN chmod -R 664 /var/cache/bind /var/lib/bind /var/log/bind

# Create and configure log files
RUN touch /var/log/bind/default.log /var/log/bind/update_debug.log /var/log/bind/security_info.log /var/log/bind/bind.log
RUN chown -R bind:bind /var/log/bind
RUN chmod 644 /var/log/bind/*.log

# Define volumes
VOLUME ["/etc/bind", "/var/cache/bind", "/var/lib/bind", "/var/log/bind"]

# Set the entrypoint to the named executable
ENTRYPOINT ["/usr/sbin/named"]

# Set the default command arguments for the named executable
CMD ["-g"]

I keep getting this error when I run it with podman:

26-Jul-2024 03:18:21.328 loading configuration from '/etc/bind/named.conf'
26-Jul-2024 03:18:21.328 directory '/var/cache/bind' is not writable
26-Jul-2024 03:18:21.332 /etc/bind/named.conf.options:2: parsing failed: permission denied

As you can see from the CONTAINERFILE, the bind user should be able to read and write to /var/cache/bind but for some reason it doesn’t.

I have been at this for a while and I’m at my wits end. Your help is appreciated!

  • Findmysec@infosec.pubOP
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    3 months ago

    This is a very useful trick, thanks.

    The problem was with the chmod, I changed it to include execute permissions for the user (764) and it worked. I’m also running named with a -u bind flag in “ENTRYPOINT” for insurance.