Resources

My main resources for this post is the talk here:

https://www.youtube.com/watch?v=ALn0hUxNszI&t=1288s

Credit to the Author.

I just took what he’s doing and made it work on my machine, instead of MIPS I’m running ARM though. I expand upon the examples in the talk by adding some stuff of my own.

Create a Dockerfile

MIPS from the talk in [Resources]:

FROM multiarch/debian-debootstrap:mips-buster-slim as qemu
FROM scratch
ADD ./firmware.tar.gz /
COPY --from=qemu /usr/bin/qemu-mips-static /usr/bin
CMD ["/usr/bin/qemu-mips-static", "bin/busybox"]
ENV ARCH=mips

ARM from my setup:

FROM multiarch/debian-debootstrap:armel-buster-slim as qemu
FROM scratch
ADD ./firmware.tar.gz /
COPY --from=qemu /usr/bin/qemu-arm-static /usr/bin
CMD ["/usr/bin/qemu-arm-static", "bin/busybox"]
ENV ARCH=arm

Build the Container

Use the command:

docker build --rm -t [NAME] -f dockerfile .

# example
docker build --rm -t ARMcontainer -f dockerfile .

Run the Container

Running the container is straight forward, however, I needed to load shared libaries as shown below.

docker run -it --rm [NAME]:latest [EXECUTABLE]

# example
docker run -it --rm router:latest sh

# in my case for the target firmware
docker run -it --rm armdocker:latest lib/ld-linux.so.3 --library-path lib/ userdisk/ControlCenter

Manually Loading Shared Libraries

docker run -it --rm armdocker:latest lib/ld-linux.so.2 --library-path lib/ bin/busybox
docker run -it --rm armdocker:latest lib/ld-linux.so.2 --library-path lib/ etc/init.d/rcS

Emulation of a Firmware Image

1. get the firmware
2. extract the filesystem
3. go to the file system root directory and do tar cvf firmware.tar.gz .
4. now copy firmware.tar.gz to the directory with the dockerfile
5. build the container
6. run the container with the above commands

you should now be running an emulation of the firmware inside a docker container.