Difference between revisions of "Rootfs over encrypted lvm"

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(Added warning about different keymaps between setting the luks passphrase and entering it at boot time)
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* <code>/dev/sda2</code> -- BIOS boot partition (not needed for MBR - only needed if you are using GPT) This step required for GRUB2. For more info, see: [http://www.funtoo.org/Funtoo_Linux_Installation#Prepare_Hard_Disk] for more information on GPT and MBR.  
* <code>/dev/sda2</code> -- BIOS boot partition (not needed for MBR - only needed if you are using GPT) This step required for GRUB2. For more info, see: [http://www.funtoo.org/Funtoo_Linux_Installation#Prepare_Hard_Disk] for more information on GPT and MBR.  
* <code>/dev/sda3</code> -- <code>/</code> partition, will be the drive with LUKS and LVM.
* <code>/dev/sda3</code> -- <code>/</code> partition, will be the drive with LUKS and LVM.
With UEFI:
* <code>/dev/sda1</code> -- <tt>/boot</tt>
* <code>/dev/sda2</code> -- <tt>/</tt> partition


=== Wipe the hard drive ===
=== Wipe the hard drive ===
{{Fancywarning|This action will destroy all data on the disk.}}
<console>
<console>
# ##i##gdisk /dev/sda
# ##i##gdisk /dev/sda
Line 19: Line 22:
Blank out MBR?: ##i##y ↵
Blank out MBR?: ##i##y ↵
</console>
</console>
 
{{Fancywarning|This action will destroy all data on the disk.}}
{{Note}} You will get a message about reaching the end of the device when the <code>dd</code> command has finished. This behavior is intended.


== Encrypting the drive ==
== Encrypting the drive ==
Line 28: Line 30:
# ##i##cryptsetup luksOpen /dev/sda3 dmcrypt_root
# ##i##cryptsetup luksOpen /dev/sda3 dmcrypt_root
</console>
</console>
There you'll be prompted to enter your password phrase for encrypted drive, type your paranoid password there.
There you'll be prompted to enter your password phrase for encrypted drive, type your paranoid password there.
 
{{Fancywarning|The default keymap at boot time is '''us'''. If you enter your passphrase using a different keymap, you won't be able to unlock your crypt volume if the passphrase contains any characters that are located elsewere on your keyboard layout that with the us layout.}}
= Create logical volumes =
= Create logical volumes =
<console>
<console>
Line 71: Line 72:
= Editing the fstab =
= Editing the fstab =
Fire up your favorite text editor to edit <code>/etc/fstab</code>. You want to put the following in the file:
Fire up your favorite text editor to edit <code>/etc/fstab</code>. You want to put the following in the file:
{{File
 
|/etc/fstab|<pre>
 
<pre>
# <fs>                  <mountpoint>  <type>    <opts>                          <dump/pass>
# <fs>                  <mountpoint>  <type>    <opts>                          <dump/pass>
/dev/sda1              /boot        ext2      noauto,noatime                  1 2
/dev/sda1              /boot        ext2      noauto,noatime                  1 2
Line 80: Line 82:
/dev/mapper/vg-portage  /usr/portage  ext4      noatime,nodiratime              0 0
/dev/mapper/vg-portage  /usr/portage  ext4      noatime,nodiratime              0 0
/dev/mapper/vg-home    /home        ext4      noatime,nodiratime              0 0
/dev/mapper/vg-home    /home        ext4      noatime,nodiratime              0 0
</pre>}}
</pre>


= Kernel options =
== Kernel options ==
{{Note}}This part is particularly important: pay close attention.
{{fancynote| This part is particularly important: pay close attention. }}<br>
{{kernelop
{{kernelop
| <br> |<pre>
|title=
|desc=
General setup --->
General setup --->
       [*] Initial RAM filesystem and RAM disk (initramfs/initrd) support
       [*] Initial RAM filesystem and RAM disk (initramfs/initrd) support
</pre>}}
}}
 
{{kernelop
{{kernelop
| <br> |<pre>
|title=
|desc=
Device Drivers --->
Device Drivers --->
       Generic Driver Options --->  
       Generic Driver Options --->  
       [*] Maintain a devtmpfs filesystem to mount at /dev
       [*] Maintain a devtmpfs filesystem to mount at /dev
</pre>}}
}}
 
{{kernelop
{{kernelop
| <br> |<pre>
|title=
|desc=
Device Drivers --->
Device Drivers --->
       [*] Multiple devices driver support --->
       [*] Multiple devices driver support --->
       <*>Device Mapper Support
       <*>Device Mapper Support
         <*> Crypt target support
         <*> Crypt target support
</pre>}}
}}
 
{{kernelop
{{kernelop
| <br> |<pre>
|title=
|desc=
Cryptographic API --->
Cryptographic API --->
       <*> XTS support
       <*> XTS support
       -*-AES cipher algorithms
       -*-AES cipher algorithms
</pre>}}
}}


= Initramfs setup and configuration =
= Initramfs setup and configuration =
Line 158: Line 161:
An example <code>/etc/boot.conf</code> for better-initramfs:
An example <code>/etc/boot.conf</code> for better-initramfs:


{{File
<pre>
|/etc/boot.conf|<pre>
boot {
boot {
   generate grub
   generate grub
Line 169: Line 171:
   initrd /initramfs.cpio.gz
   initrd /initramfs.cpio.gz
   params += enc_root=/dev/sda3 lvm luks root=/dev/mapper/vg-root  rootfstype=ext4 resume=swap:/dev/mapper/vg-swap quiet
   params += enc_root=/dev/sda3 lvm luks root=/dev/mapper/vg-root  rootfstype=ext4 resume=swap:/dev/mapper/vg-swap quiet
</pre>}}
</pre>


Now, run <code>boot-update</code> to write the configuration files to <code>/boot/grub/grub.cfg</code>
Now, run <code>boot-update</code> to write the configuration files to <code>/boot/grub/grub.cfg</code>
Line 176: Line 178:
Configure the bootloader as described above, with correct kernel and initramfs images names. An example for genkernel and grub2. You will be editing <code>/etc/boot.conf</code>:
Configure the bootloader as described above, with correct kernel and initramfs images names. An example for genkernel and grub2. You will be editing <code>/etc/boot.conf</code>:


{{File
<pre>
|/etc/boot.conf|<pre>
boot {
boot {
   generate grub
   generate grub
Line 187: Line 188:
   initrd initramfs-genkernel-x86_64-3.13.0
   initrd initramfs-genkernel-x86_64-3.13.0
   params += crypt_root=/dev/sda3 dolvm real_root=/dev/mapper/vg-root  rootfstype=ext4 resume=swap:/dev/mapper/vg-swap quiet
   params += crypt_root=/dev/sda3 dolvm real_root=/dev/mapper/vg-root  rootfstype=ext4 resume=swap:/dev/mapper/vg-swap quiet
</pre>}}
</pre>


== Lilo configuration ==
== Lilo configuration ==
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Example <code>/etc/lilo.conf</code>:
Example <code>/etc/lilo.conf</code>:


{{File
<pre>
|/etc/lilo.conf|<pre>
append="init=/linuxrc dolvm crypt_root=/dev/sda2 real_root=/dev/mapper/vg-root"
append="init=/linuxrc dolvm crypt_root=/dev/sda2 real_root=/dev/mapper/vg-root"
boot=/dev/sda
boot=/dev/sda
Line 211: Line 211:
initrd=/boot/initramfs-genkernel-x86_64-3.13.0
initrd=/boot/initramfs-genkernel-x86_64-3.13.0
label=funtoo
label=funtoo
</pre>}}
</pre>


== Syslinux bootloader setup ==
== Syslinux bootloader setup ==
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Example <code>/boot/extlinux/extlinux.conf</code>:
Example <code>/boot/extlinux/extlinux.conf</code>:


{{File
<pre>
|/boot/extlinux/extlinux.conf|<pre>
LABEL kernel1_bzImage-3.2.1
LABEL kernel1_bzImage-3.2.1
MENU LABEL Funtoo Linux bzImage-3.2.1
MENU LABEL Funtoo Linux bzImage-3.2.1
Line 234: Line 233:
INITRD /initramfs.cpio.gz
INITRD /initramfs.cpio.gz
APPEND rootfstype=ext4 luks enc_root=/dev/sda2 lvm root=/dev/mapper/vg-root
APPEND rootfstype=ext4 luks enc_root=/dev/sda2 lvm root=/dev/mapper/vg-root
</pre>}}
</pre>


= Final steps =
== Final steps ==
Umount everything, close encrypted drive and reboot
Umount everything, close encrypted drive and reboot
<console>
<console>
Line 276: Line 275:
</console>
</console>


= Additional links and information =
== Additional links and information ==
* [[gentoo-wiki:Root filesystem over LVM2, DM-Crypt and RAID|Root filesystem over LVM2, DM-Crypt, and RAID]]
* [[gentoo-wiki:Root filesystem over LVM2, DM-Crypt and RAID|Root filesystem over LVM2, DM-Crypt, and RAID]]
* [http://wiki.archlinux.org/index.php/System_Encryption_with_LUKS_for_dm-crypt System Encryption with LUKS for dm-crypt]
* [http://wiki.archlinux.org/index.php/System_Encryption_with_LUKS_for_dm-crypt System Encryption with LUKS for dm-crypt]

Revision as of 11:57, July 19, 2014

This howto describes how to setup LVM and rootfs with cryptoLUKS-encrypted drive. It is not meant to be a standalone installation guide, rather, it is meant to be read alongside the Funtoo Linux Installation Guide.

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 -- /boot partition.
  • /dev/sda2 -- BIOS boot partition (not needed for MBR - only needed if you are using GPT) This step required for GRUB2. For more info, see: [1] for more information on GPT and MBR.
  • /dev/sda3 -- / partition, will be the drive with LUKS and LVM.

With UEFI:

  • /dev/sda1 -- /boot
  • /dev/sda2 -- / partition

Wipe the hard drive

root # gdisk /dev/sda

Command: x ↵
Expert command: z ↵
About to wipe out GPT on /dev/sda. Proceed?: y ↵
GPT data structures destroyed! You may now partition the disk using fdisk or other utilities.
Blank out MBR?: y ↵
   Warning

This action will destroy all data on the disk.

Encrypting the drive

Read more about different cipher options here: [2]

root # cryptsetup --cipher aes-xts-plain64 luksFormat /dev/sda3
root # cryptsetup luksOpen /dev/sda3 dmcrypt_root

There you'll be prompted to enter your password phrase for encrypted drive, type your paranoid password there.

   Warning

The default keymap at boot time is us. If you enter your passphrase using a different keymap, you won't be able to unlock your crypt volume if the passphrase contains any characters that are located elsewere on your keyboard layout that with the us layout.

Create logical volumes

root # pvcreate /dev/mapper/dmcrypt_root
root # vgcreate vg /dev/mapper/dmcrypt_root
root # lvcreate -L10G --name root vg           
root # lvcreate -L2G --name swap vg
root # lvcreate -L5G --name portage vg
root # lvcreate -l 100%FREE -nhome vg

Feel free to specify your desired size by altering the numbers after the -L flag. For example, to make your portage dataset 20GB's, use the flag -L20G instead of -L5G.

Create a filesystem on volumes

root # mkfs.ext2 /dev/sda1
root # mkswap /dev/mapper/vg-swap
root # mkfs.ext4 /dev/mapper/vg-root
root # mkfs.ext4 /dev/mapper/vg-portage
root # mkfs.ext4 /dev/mapper/vg-home

Basic system setup

root # swapon /dev/mapper/vg-swap
root # mkdir /mnt/funtoo
root # mount /dev/mapper/vg-root /mnt/funtoo
root # mkdir -p /mnt/funtoo/{boot,usr/portage,home}
root # mount /dev/sda1 /mnt/funtoo/boot
root # mount /dev/mapper/vg-portage /mnt/funtoo/usr/portage
root # mount /dev/mapper/vg-home /mnt/funtoo/home

Now perform all the steps required for basic system install, please follow [3] don't forget to emerge the following before your install is finished:

  • cryptsetup
  • lvm2
  • a bootloader (grub recommended)
  • kernel sources

Editing the fstab

Fire up your favorite text editor to edit /etc/fstab. You want to put the following in the file:


# <fs>                  <mountpoint>  <type>    <opts>                          <dump/pass>
/dev/sda1               /boot         ext2      noauto,noatime                  1 2
/dev/mapper/vg-swap     none          swap      sw                              0 0
/dev/mapper/vg-root     /             ext4      noatime,nodiratime,defaults     0 1
/dev/sr0                /mnt/cdrom    auto      noauto,ro                       0 0
/dev/mapper/vg-portage  /usr/portage  ext4      noatime,nodiratime              0 0
/dev/mapper/vg-home     /home         ext4      noatime,nodiratime              0 0

Kernel options

   Note
This part is particularly important: pay close attention. 


General setup --->
      [*] Initial RAM filesystem and RAM disk (initramfs/initrd) support
Device Drivers --->
      Generic Driver Options ---> 
      [*] Maintain a devtmpfs filesystem to mount at /dev
Device Drivers --->
      [*] Multiple devices driver support --->
      <*>Device Mapper Support
        <*> Crypt target support
Cryptographic API --->
      <*> XTS support
      -*-AES cipher algorithms

Initramfs setup and configuration

Better-initramfs

Build your initramfs with better-initramfs project.

   Note

{{{1}}}

better-initramfs supports neither dynamic modules nor udev, so you should compile your kernel with built-in support for your block devices and file system support.

root # cd /opt
root # git clone git://github.com/slashbeast/better-initramfs.git
root # cd better-initramfs
root # less README.rst
root # bootstrap/bootstrap-all
root # make prepare
root # make image

Copy resulting initramfs.cpio.gz to /boot:

root # cp output/initramfs.cpio.gz /boot

Alternatively, a pre-compiled binary initramfs is available at https://bitbucket.org/piotrkarbowski/better-initramfs/downloads

root # wget https://bitbucket.org/piotrkarbowski/better-initramfs/downloads/release-x86_64-v0.7.2.tar.bz2
root # tar xf release-x86_64-v0.5.tar.bz2
root # cd release*
root # gzip initramfs.cpio
root # 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:

root # cd /opt/better-initramfs
root # git pull
root # less ChangeLog
   Note

{{{1}}}

Please read the ChangeLog carefuly and perform necessary updates to /etc/boot.conf. Also, please backup the working /boot/initramfs.cpio.gz and /etc/boot.conf before updating better-initramfs.

Genkernel

Funtoo's genkernel capable to create initramfs for encrypted drive. Compile and install kernel and initramfs of your favorite kernel sources:

root # genkernel --kernel-config=/path/to/your/custom-kernel-config --no-mrproper --makeopts=-j5 --install --lvm --luks all 

Bootloader Configuration

Grub2 configuration

better-initramfs

An example /etc/boot.conf for better-initramfs:

boot {
  generate grub
  default "Funtoo Linux"
  timeout 3
}
"Funtoo Linux" {
  kernel vmlinuz[-v]
  initrd /initramfs.cpio.gz
  params += enc_root=/dev/sda3 lvm luks root=/dev/mapper/vg-root  rootfstype=ext4 resume=swap:/dev/mapper/vg-swap quiet

Now, run boot-update to write the configuration files to /boot/grub/grub.cfg

genkernel

Configure the bootloader as described above, with correct kernel and initramfs images names. An example for genkernel and grub2. You will be editing /etc/boot.conf:

boot {
  generate grub
  default "Funtoo Linux"
  timeout 3
}
"Funtoo Linux" {
  kernel kernel-genkernel-x86_64-3.13.0
  initrd initramfs-genkernel-x86_64-3.13.0
  params += crypt_root=/dev/sda3 dolvm real_root=/dev/mapper/vg-root  rootfstype=ext4 resume=swap:/dev/mapper/vg-swap quiet

Lilo configuration

For oldschool geeks, an example for lilo bootloader. Emerge lilo with device-mapper support

root # echo 'sys-boot/lilo device-mapper' >> /etc/portage/package.use/lilo
root # emerge lilo

Example /etc/lilo.conf:

append="init=/linuxrc dolvm crypt_root=/dev/sda2 real_root=/dev/mapper/vg-root"
boot=/dev/sda
compact
default=funtoo
lba32
prompt
read-only
timeout=50
image=/boot/kernel-genkernel-x86_64-3.13.0
initrd=/boot/initramfs-genkernel-x86_64-3.13.0
label=funtoo

Syslinux bootloader setup

Syslinux is another advanced bootloader which you can find on all live CD's. Syslinux bootloader does not require additional BIOS boot partition. /dev/sda2 is the root partition.

root # emerge syslinux
root # mkdir /boot/extlinux
root # extlinux --install /boot/extlinux
root # dd bs=440 conv=notrunc count=1 if=/usr/share/syslinux/mbr.bin of=/dev/sda
- or -
root # sgdisk /dev/sda --attributes=1:set:2
root # dd bs=440 conv=notrunc count=1 if=/usr/share/syslinux/gptmbr.bin of=/dev/sda, for GPT partition

Example /boot/extlinux/extlinux.conf:

LABEL kernel1_bzImage-3.2.1
MENU LABEL Funtoo Linux bzImage-3.2.1
LINUX /bzImage-3.2.1
INITRD /initramfs.cpio.gz
APPEND rootfstype=ext4 luks enc_root=/dev/sda2 lvm root=/dev/mapper/vg-root

Final steps

Umount everything, close encrypted drive and reboot

root # umount -l -v /mnt/funtoo/{dev, proc, home, usr/portage, boot} 
root # vgchange -a n
root # 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
   
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Password:
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Additional links and information