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⇤ ← Revision 1 as of 2017-10-10 23:49:15
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| While encrypting your disks is a good idea, it also presents you with the problem that you have to enter the passphrase when booting the system. Entering the passphrase is really what the security is about, so circumventing this is really hosing you security. | While encrypting your disks is a good idea, it also presents you with the problem that you have to enter the passphrase when booting the system. Running the KVM Host as a headless system with no keyboard attached really introduces a problem. Entering the passphrase is what the security is about, so circumventing this is really hosing you security. |
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| find yourself a good passphrase echo -n "uptime" | md5sum | dd of=keyfile_md1 bs=1 count=32 |
== Add a New Luks Key == |
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| cryptsetup luksAddKey /dev/md1 keyfile_md1 | Find yourself a good passphrase. {{{ $ echo -n "uptime" | md5sum | dd of=keyfile_md1 bs=1 count=32 }}} Add the New Key. {{{ # cryptsetup luksAddKey /dev/md1 keyfile_md1 |
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| }}} | |
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| insert your usb storage device, has to hold 32 bytes, hard to find a device that small i use a 4GB usb storage device myself | == Put the Key on A USB Storage Device == |
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| make the usb storage device look like its just garbage data | Insert your usb storage device, has to hold 32 bytes, hard to find a device that small I use a 4GB usb storage device myself. Make the usb storage device look like its just garbage data. |
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| dd if=/dev/urandom of=/dev/sde | {{{ # dd if=/dev/urandom of=/dev/sde }}} |
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| put the key on it | Put the key on it. |
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| dd if=keyfile_md1 of=/dev/sde | {{{ # dd if=keyfile_md1 of=/dev/sde }}} |
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== Getting the Initramfs == |
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| }}} |
KVM Host Booting from Luks Encryption
While encrypting your disks is a good idea, it also presents you with the problem that you have to enter the passphrase when booting the system. Running the KVM Host as a headless system with no keyboard attached really introduces a problem. Entering the passphrase is what the security is about, so circumventing this is really hosing you security.
Add a New Luks Key
Find yourself a good passphrase.
$ echo -n "uptime" | md5sum | dd of=keyfile_md1 bs=1 count=32
Add the New Key.
# cryptsetup luksAddKey /dev/md1 keyfile_md1 Enter any existing passphrase:
Put the Key on A USB Storage Device
Insert your usb storage device, has to hold 32 bytes, hard to find a device that small I use a 4GB usb storage device myself. Make the usb storage device look like its just garbage data.
# dd if=/dev/urandom of=/dev/sde
Put the key on it.
# dd if=keyfile_md1 of=/dev/sde
Getting the Initramfs
ok now we have the key on our usb-storage device. Next we need to initrd image to be able to use that information.
SOURCE="/dev/md1"
TARGET="md1_crypt"
while [ ! -e /dev/mapper/${TARGET} ]
do
while read a b c DEVICE
do
if [ ! -e /dev/mapper/${TARGET} ]
then
if [ -e /dev/${DEVICE} ]
then
#echo -n "$DEVICE "
dd if=/dev/${DEVICE} of=proposedkey bs=1 count=32 > /dev/null 2>&1
cryptsetup luksOpen ${SOURCE} ${TARGET} --key-file proposedkey > /dev/null 2>&1
fi
fi
done</proc/partitions
done
cryptsetup luksClose /dev/mapper/${TARGET}
cat proposedkeythis script is not optimized in any way, but it checks all partitions in /proc/partitions until it finds a valid key. Save the script as root/install/luks/keyscript.sh
now edit /etc/crypttab
md1_crypt UUID=72deeb7f-2289-40c5-99c1-52238afb78ef none luks
becomes md1_crypt UUID=72deeb7f-2289-40c5-99c1-52238afb78ef none luks,keyscript=/root/install/luks/keyscript.sh
update-initramfs -u update-grub
reboot and test