Reading a LUKS keyfile from a FAT USB Drive during boot

[Philipp Ludwig]

My laptop is running an encrypted funtoo installation, which prompts me for the password of the root volume during boot. This works nice, but since I'm lazy I'd like to read the key from an USB drive.

Using the commandline parameter root_key=keyfile.bin this works fine if I boot my custom kernel, where support for FAT fileystems is built into the kernel (not as a module).

However, using the debian kernel this does not work, since the initramfs cannot mount the device - I guess because of missing support for the FAT fileysystem. I tried adding fat and vfat to /usr/share/genkernel/defaults in the line MODULES_FS, but without any luck.

Is this even possible or do I need to use something like ext4 on the USB drive?

[Oleg Vinichenko]

ext4 is also a module in debian kernel. the fix to it would loading the keyboard/usb modules before the luks and before mounting the rootfs. Currently genkernel does not do this. Alternatively those can be compiled in and not modules.

[mf2]

Thanks for your explanation and ongoing support oleg! I will look into alternative builder for the initramfs and maybe add a guide for the Surface Pro 4 to the Wiki. I will mark this as solved for now.

Edit: Wow, seems that I have made two different accounts. That's embarassing.