Kernel module determination error messages should be more verbose

[steev]

I am running into an issue where I am attempting to run fakemachine inside either a podman or a docker container, and with both of them, I am simply getting the error:

fakemachine: modules path couldn't be determined

For example:

┌──(root㉿buildbox)-[/source]
└─# fakemachine -m 4096 -s 32G -v $(pwd) -b kvm
fakemachine: modules path couldn't be determined

┌──(root㉿buildbox)-[/source]
└─# uname -a
Linux buildbox 6.12.20-amd64 #1 SMP PREEMPT_DYNAMIC Kali 6.12.20-1kali1 (2025-03-26) x86_64 GNU/Linux

┌──(root㉿buildbox)-[/source]
└─# ls /lib/modules/6.12.20-amd64/                                                                                      
kernel             modules.builtin            modules.builtin.modinfo  modules.devname  modules.symbols
modules.alias      modules.builtin.alias.bin  modules.dep              modules.order    modules.symbols.bin
modules.alias.bin  modules.builtin.bin        modules.dep.bin          modules.softdep  modules.weakdep

┌──(root㉿buildbox)-[/source]
└─# ls /lib/modules/6.12.20-amd64/kernel/
arch  block  crypto  drivers  fs  lib  mm  net  sound

The modules are there, and if I run fakemachine on the host, instead of in docker or podman, it runs just fine.

Edit: So, my Dockerfile looks like this:

FROM docker.io/kalilinux/kali-rolling

RUN apt-get update \
 && apt-get install --no-install-recommends -y \
    arch-test autoconf automake bc bison \
    build-essential cgpt cgroup-tools cmake \
    crossbuild-essential-arm64 \
    crossbuild-essential-armhf \
    crossbuild-essential-armel \
    curl dbus device-tree-compiler dosfstools \
    e2fsprogs eatmydata flex gawk \
    gcc-arm-none-eabi git gnupg kpartx \
    libncurses-dev libgnutls28-dev lsb-release \
    libssl-dev lsof lzma lzop m4 make mmdebstrap \
    parted pixz pkg-config python3-dev qemu-user-static \
    rsync swig u-boot-tools uuid-dev \
 && apt-get install --no-install-recommends -y \
    fakemachine \
 && apt-get clean

Just a quick and dirty one to try to get things working, while keeping the image small. However, if I simply remove that --no-install-recommends from the fakemachine install line, then I am able to start fakemachine inside docker/podman without issue.

Potentially related, it would be nice to know what kernel module options are required for this to work properly. I run a custom kernel build on an arm64 laptop and I cannot seem to fully figure out the options to make fakemachine work. I either run into the modules path couldn't be determined, or I run into #196 which means I am missing something else, but I do not know what it might be.

[obbardc]

@steev can you please add another issue for the second question?

[obbardc]

@steev can you please add another issue for the second question?

I created #268 to capture that request.

[obbardc]

@steev it's a bit hard to reproduce this issue (of course i do agree the error message needs to be improved)

but I added this to the Dockerfile from #266 near the end:

RUN rm -rf /usr/lib/modules/*/kernel/*

and I get:

fakemachine: modules path couldn't be determined

so that's a good start!

[steev]

Hi @obbardc unfortunately, that machine is no longer accessible to me, and iirc, I was trying to build a Docker image with fakemachine installed on it to use as part of trying to build the kali arm images inside of Gitlab CI (to get around needing to run private runners) - iirc, I ended up needing to install linux-image-$DEBARCH (where debarch is a variable for the debian architecture) in order to get it to run correctly in the Docker/podman image - I think it was needing the kernel image to be installed.

I wish I still had access to the systems, but unfortunately I was laid off and no longer have access.

[obbardc]

Hi @obbardc unfortunately, that machine is no longer accessible to me, and iirc, I was trying to build a Docker image with fakemachine installed on it to use as part of trying to build the kali arm images inside of Gitlab CI (to get around needing to run private runners) - iirc, I ended up needing to install linux-image-$DEBARCH (where debarch is a variable for the debian architecture) in order to get it to run correctly in the Docker/podman image - I think it was needing the kernel image to be installed.

I wish I still had access to the systems, but unfortunately I was laid off and no longer have access.

Sorry to hear that :/.

I think this issue is still valid, the error message when not finding kernel or specific modules isn't very descriptive at all and the code needs reworking to bubble up errors. So I'd like to keep this issue open and propose a fix when I get some time.