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Need help: USB unlock LUKS on Alpine Linux
(lemmy.zip)
Hi folks,
I have Alpine Linux installed in an encrypted LUKS partition. I came across this tutorial which shows how to setup a key in a USB drive and when the drive is inserted and the computer booted, the LUKS partition auto-unlocks with the key on the USB drive.
I would like to setup the same thing but I do not have Alpine linux installed on ZFS, so I'm looking for ways to adapt the instructions.
So far, what I've done is:
- I've setup the key on the usb stick and I can unlock the LUKS partition with that key.
- create a
/etc/mkinitfs/features.d/usb-unlock.shscript with the following content:
(the echo to /dev/kmesg was to check whether the script did indeed run at boot by trying to print to the kernel messages but I can't find anything in the kernel messages).
#!/bin/sh
echo "usb-unlock script starting..." > /dev/kmsg
USB_MOUNT="/mnt/my-usb-key" # The USB stick mounting point
LUKS_KEY_FILE="awesome.key" # The name of your keyfile on the USB stick
# Search for the USB stick with the key
for device in $(ls /dev/disk/by-uuid/*); do
mount $device $USB_MOUNT 2>/dev/null
if [ -f "$USB_MOUNT/$LUKS_KEY_FILE" ]; then
# Unlock the LUKS partition
cryptsetup luksOpen /dev/sda3 cryptroot \
--key-file "$USB_MOUNT/$LUKS_KEY_FILE" && exit 0
fi
umount $USB_MOUNT
done
echo "No USB key found, falling back to password prompt." # this message never appears, despite not having found the key on the usb stick
echo "usb-unlock script ending." > /dev/kmsg
- I added
usb-unlockto thefeaturesinmkinitfs.conf:
mytestalpine:~# cat /etc/mkinitfs/mkinitfs.conf
features="ata base ide scsi usb virtio ext4 cryptsetup keymap usb-unlock"
- run
mkinitfsto rebuild the initramfs. Then reboot to test the implementation, which was unsuccessful.
What am I missing / doing wrong? Thank you for your help!
Edit: forgot to add step 4
sleep.
my tip: put your phone on silent and place it in another room to prevent you from reflexively taking it while you struggle to fall asleep. just make sure to have the alarm volume be high enough for you to wake up.