[Bug]: sudo execution failed during customize-image.sh execution

[Lebensgefahr]

What happened?

This is not actually a bug and can be closed, but I hope it will save other users time.

I am building an Armbian image for my printer. customize-image.sh is used to install Klipper and other related software using KIAUH.
I encountered the following error:
sudo: effective uid is not 0, is /usr/bin/sudo on a file system with the 'nosuid' option set or an NFS file system without root privileges?

This happened while running:
printf '1\n1\n1\nn\n2\nY\n4\nY\n80\nB\nQ\n' | sudo -u mks ./kiauh.sh

mks is an unprivileged user with passwordless sudo.
KIAUH attempts to install packages and complete command can look like this:
sudo -u mks sudo SOMETHING

The previous build succeeded on September 6, 2025. I remember that missing qemu-user-static package caused build failures.
I did not change anything in customize-image.sh, but the build started failing.
After investigating, I discovered that the C flag was missing in the binfmt_misc entry for qemu-aarch64:

cat /proc/sys/fs/binfmt_misc/qemu-aarch64 
enabled
interpreter /usr/libexec/qemu-binfmt/aarch64-binfmt-P
flags: PF
offset 0
magic 7f454c460201010000000000000000000200b700
mask ffffffffffffff00fffffffffffffffffeffffff

As described here:
https://en.wikipedia.org/wiki/Binfmt_misc
The fix is:

sudo bash -c 'echo -1 > /proc/sys/fs/binfmt_misc/qemu-aarch64'
sudo bash -c 'echo ":qemu-aarch64:M::\x7f\x45\x4c\x46\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\xb7\x00:\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff:/usr/libexec/qemu-binfmt/aarch64-binfmt-P:CFP" > /proc/sys/fs/binfmt_misc/register'

After that:

cat /proc/sys/fs/binfmt_misc/qemu-aarch64 
enabled
interpreter /usr/libexec/qemu-binfmt/aarch64-binfmt-P
flags: POCF
offset 0
magic 7f454c460201010000000000000000000200b700
mask ffffffffffffff00fffffffffffffffffeffffff

How to reproduce?

Create an unprivileged user inside custimize-image.sh with sudoers.d file and run:

sudo -u UNPRIVILIGED_USER_WITH_SUDO sudo

Branch

main (main development branch)

On which host OS are you running the build script and observing this problem?

Ubuntu 24.04 Noble

Are you building on Windows WSL2?

• Yes, my Ubuntu/Debian/OtherOS is running on WSL2

Relevant log URL

No response

Code of Conduct

• I agree to follow this project's Code of Conduct

[github-actions]

Jira ticket: AR-2786