Rootfs over encrypted lvm
This howto describes how to setup LVM and rootfs with cryptoLUKS-encrypted drive
Prepare the hard drive and partitions
This is an example partition scheme, you may want to choose differently.
/dev/sda1 used as /boot. /dev/sda2 will be encrypted drive with LVM.
/dev/sda1 /dev/sda2 dd if=/dev/zero of=/dev/sda2 bs=100M dd if=/dev/urandom of=/dev/sda2 bs=100M
dd part is optional, only for security reason by overwriting the lingering data on the device with random data. It takes around 6 hours to complete for a 200GB drive.
Note that you will get a message about reaching the end of the device. That's intentional and desired in this case so that this command works without knowing the size of your device.
Encrypting the drive
root # cryptsetup -c aes-xts-plain64 luksFormat /dev/sda2 root # cryptsetup luksOpen /dev/sda2 dmcrypt_root
There you'll be prompted to enter your password phrase for encrypted drive, type your paranoid password there.
Create logical volumes
pvcreate /dev/mapper/dmcrypt_root vgcreate vg /dev/mapper/dmcrypt_root lvcreate -L10G -nroot vg lvcreate -L2G -nswap vg lvcreate -L5G -nportage vg lvcreate -l 100%FREE -nhome vg
Feel free to specify your desired size
Create a filesystem on volumes
mkfs.ext2 /dev/sda1 mkswap /dev/mapper/vg-swap mkfs.ext4 /dev/mapper/vg-root mkreiserfs /dev/mapper/vg-portage mkfs.xfs /dev/mapper/vg-home
Basic system setup
swapon /dev/mapper/vg-swap mount /dev/mapper/vg-root /mnt/funtoo mkdir /mnt/funtoo/boot mount /dev/sda1 /mnt/funtoo/boot
Now perform all the steps required for basic system install, please follow [1] don't forget to emerge next packages:
# emerge cryptsetup lvm2 grub foo-sources
Re-emerge sys-apps/busybox and sys-fs/cryptsetup with the "static" USE flag
Kernel options
Important, do not miss this part. Under General setup --->
[*] Initial RAM filesystem and RAM disk (initramfs/initrd) support
Under Device Drivers --->
Generic Driver Options ---> [*] Maintain a devtmpfs filesystem to mount at /dev [*] Multiple devices driver support ---> <*>Device Mapper Support <*> Crypt target support
Under Cryptographic API --->
-*-AES cipher algorithms <*> XTS support (EXPERIMENTAL)
Initramfs setup and configuration
Build your initramfs with better-initramfs project.
better-initramfs supports neither dynamic modules nor udev, so you should compile your kernel with built-in support for your block devices.
# git clone git@bitbucket.org:piotrkarbowski/better-initramfs.git # cd better-initramfs # less README.rst # bootstrap/bootstrap-all # make prepare # make image
Copy resulting initramfs.cpio.gz to /boot.
# cp output/initramfs.cpio.gz /boot
Alternatively pre-compiled binary initramfs available at https://bitbucket.org/piotrkarbowski/better-initramfs/downloads
# wget https://bitbucket.org/piotrkarbowski/better-initramfs/downloads/release-x86_64-v0.7.2.tar.bz2 # tar xf release-x86_64-v0.5.tar.bz2 # cd release* # gzip initramfs.cpio # cp initramfs.cpio.gz /boot
Remember, better-initramfs project is a work in progress, so you need to update from time to time. It can be done easily with git. Go to the better-initramfs source dir and follow:
# git pull # less ChangeLog
Please, read the ChangeLog carefuly and do necessary updates, to /etc/boot.conf, the example config below. Please, backup working initramfs.cpio.gz and /etc/boot.conf before updating initramfs.
Genkernel approach
Funtoo's genkernel capable to create initramfs for encrypted drive. Compile and install kernel and initramfs of your favorite kernel sources:
genkernel --kernel-config=/path/to/your/custom-kernel-config --no-mrproper --makeopts=-j5 --install --lvm --luks all
Configure the bootloader as described above, with correct kernel and initramfs images names. An example for genkernel and grub2:
Grub2 configuration
An example of /etc/boot.conf for better-initramfs
Template:Code
Lilo configuration
For oldschool geeks, an example for lilo bootloader. Emerge lilo with device-mapper support
# echo 'sys-boot/lilo device-mapper' >> /etc/portage/package.use/lilo # emerge lilo
Syslinux bootloader setup
Syslinux is another advanced bootloader which you can find on all live CD's.
# emerge syslinux # mkdir /boot/extlinux # extlinux --install /boot/extlinux # dd bs=440 conv=notrunc count=1 if=/usr/share/syslinux/mbr.bin of=/dev/sda - or - # sgdisk /dev/sda --attributes=1:set:2 # dd bs=440 conv=notrunc count=1 if=/usr/share/syslinux/gptmbr.bin of=/dev/sda, for GPT partition
Final steps
Umount everything, close encrypted drive and reboot
umount /mnt/funtoo/proc (/dev, /home, /usr/portage, /boot) vgchange -a n cryptsetup luksClose /dev/sda2 dmcrypt_root
After reboot you will get the following:
>>> better-initramfs started. Kernel version 2.6.35-gentoo-r10 >>> Create all the symlinks to /bin/busybox. >>> Initiating /dev/dir >>> Getting LVM volumes up (if any) Reding all physical volumes. This make take awhile... No volume group found No volume group found >>> Opening encrypted partition and mapping to /dev/mapper/dmcrypt_root Enter passphrase fore /dev/sda2:
Type your password
>>> Again, getting LVM volumes up (if any, after map dmcrypt). Reading all physical volumes. This may take a while... Found volume group "vg" using metadata type lvm2 4 logical volume(s) in volume group "vg" now active >>> Mounting rootfs to /newroot >>> Umounting /sys and /proc. >>> Switching root to /newroot and executing /sbin/init. INIT: version 2.88 booting Loading /libexec/rc/console/keymap OpenRC 0.6.1 is starting up Funtoo Linux (x86_64) ...boot messages omitted for clarity orion login: oleg Password: Last login: Thu Oct 14 20:49:21 EEST 2010 on tty1 oleg@orion ~ %