PVE mit ZFS und native encryption

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Proxmox Virtual Environment hat meinen alten XEN Server abgelöst. Die Festplatten werden wieder verschlüsselt, damit beim Wechsel diese nicht mehr gelöscht werden müssen.

Installation von PVE mit ZFS

Die Installation erfolgte mittels ISO Datei auf einem USB-Stick. Als Filesystem wählte ich ZFS mit RAID 1 auf zwei SSD mit Standard Parametern.

Lokale Anpassungen

Deaktiviere Proxmox Subscription Warnung

Deaktivierung der nervigen Warnung über eine fehlende Subscription: Über /etc/rc.local starte ich ein kleines script remove-proxmox-subscription-notice.sh

Encrypted ZFS Volume

Ich habe ein Verzeichnis '/etc/cryptkey' angelegt, dass alle zur Verschlüsselung notwendigen Dateien aufnimmt:

  • keymanager_zfs.sh - Key Management Tool
  • keyscript.sh - Startscript (Bootprozess)
  • key_zfs.conf - Konfigurationsdetails
  • root - Zertifikat (ZFS KEY)
root# ls -l /etc/cryptkey
-rwxr-x--- 1 root root 9542 Dec 19 22:40 keymanager_zfs.sh
-rwxr-x--- 1 root root  680 Dec 19 20:49 keyscript_zfs.sh
-r-------- 1 root root  859 Dec 19 21:46 key_zfs.conf
-r-------- 1 root root  130 Dec 19 20:49 root

Das Key Management Tool keymanagement.sh habe ich in einem Forum gefunden. Damit wird ein zufälliger 64-Byte KEY mit SSL verschlüsselt und mit einem (SSL-) Passwort versehen abgespeichert.

Dieser ZFS KEY (/etc/cryptkey/root) kann nur mit dem SSL Passwort ausgelesen werden. Das Passwort wird aber nicht auf der Festplatte gespeichert, die das ZFS Volume beherbergt. Trotzdem soll der Bootvorgang das ZFS Volume mit diesem KEY ohne (manuelle!) Eingabe des Passworts entschlüsseln können - aber nicht müssen.

Die Lösung: Der KEY wird nicht nur im File root mittels SSL verschlüsselt gespeichert, sondern auch auf einem USB-Stick. Dabei kann ein anderes Passwort verwendet werden - muss aber nicht. Ich verwende für jeden USB-Stick ein individuelles Passwort, welches ich nirgends extra speichern möchte. Als Passwort verwende ich daher die ID des USB-Sticks: /dev/diskby-id/<usb-stick-id> Dieses steht auf dem Server automatisch zur Verfügung, ohne das es irgendwo gespeichert ist. Der Server kann also das verschlüsselte ZFS Volume mit dem auf dem Stick gespeicherten, SSL verschlüsseltem KEY entschlüsseln, indem er als Passwort seine eigene ID verwendet.

Steckt der USB-Stick nicht im Server, wird der KEY aus dem File root ausgelesen, was allerdings eine manuelle Eingabe des Passwortes erfordert. Das wird im Bootvorgang also fehlschlagen, der Server bootet, ohne das verschlüsselte ZFS Volume zu mounten.

Ein Aufruf des Startscriptes keyscript.sh liest in diesem Falle den ZFS KEY aus dem File root aus, fragt dabei das Passwort manuell ab, und bindet das Volume in einem solchen Fall nachträglich ein.

ZFS KEY anlegen

ZFS KEY erzeugen, mit SSL verschlüsseln und speichern. Default ist 64BYTE mit Filename = <userid> (also root). 

root# cd /etc/cryptkey
./keymanager makekey

encrypted ZFS Volume anlegen

Default ist Filename = <userid> (also root). 

./keymanager_zfs.sh zfscreate -v rpool/encrypted_data

Unlock encrypted ZFS Pool

Files

/root

remove-proxmox-subscription-notice.sh

Das Script remove-proxmox-subscription-notice.sh sdeaktiviert die Subscription Warnung im Webinterface. Ich starte es über /etc/rc.local. 

#!/bin/sh
sed -Ezi.bak "s/(Ext.Msg.show\(\{\s+title: gettext\('No valid sub)/void\(\{ \/\/\1/g" /usr/share/javascript/proxmox-widget-toolkit/proxmoxlib.js && systemctl restart pveproxy.service

/etc/rc.local

Deaktiviere Subscription Warnung, aktiviere den encrypted ZFS Pool. 

#!/bin/sh -e
# local init script

# load ZFS encryption key on boot from USB Stick
if [ -r /etc/cryptkey/key_zfs.conf ]; then
    /etc/cryptkey/keyscript_zfs.sh
fi

/root/remove-proxmox-subscription-notice.sh

# evtl. Sleepmodus für HDD Festplatten aktivieren
#[ -e /dev/sda ] && hdparm -Y -S 242 /dev/sda || true
#[ -e /dev/sdb ] && hdparm -Y -S 242 /dev/sdb || true

mount -a

exit 0

/etc/cryptkey

key_zfs.conf

Definition wo auf dem USB Stick der ZFS KEY gespeichert wird, und wie das ZFS Volume heisst:

  • USB_ZFSVOL - verschlüsseltes ZFS Volume
  • USB_STICK - USB Stick Name (ID)
# config file for ZFS encryption with multiple keyfiles
#
# concept: the keyfile for ZFS encryption is stored
#          on an USB Stick, encrypted with a fixed password (used for booting)
#          on filesystem, encrypted with a different password (not in any script)
#
# this gives the possibility to load the ZFS encryption key
#   - at boot without password prompt ==> if the USB_STICK is connected
#   - manually with a different(!) password ==> if the USB_STICK is defect

# name of encrypted ZFS volume
USB_ZFSVOL=rpool/encrypted_data

# name of USB Stick on /dev/disk/by-id
USB_STICK=usb-Memorybird_P_100074AE3400109-0:0

# where the encrypted password is stored on USB Stick (raw data before 1st partition)
USB_SKIP=2560
USB_COUNT=130
USB_BSIZE=1
USB_PASSWORD=$USB_STICK

keyscript.sh

Startscript für den Bootvorgang, wird aus /etc/rc.local gestartet. 

#!/bin/bash

CONFIG=/etc/cryptkey/key_zfs.conf
SCRIPT=/etc/cryptkey/keymanager_zfs.sh
ENC_KEY=/run/.cryptkey/usb_key_zfs.enc

[ -r $CONFIG ] || exit 0
. $CONFIG

if [ -e /dev/disk/by-id/$USB_STICK ]; then

    # extract encrypted key from usb stick
    mkdir -p $(dirname $ENC_KEY)
    chmod 400 $(dirname $ENC_KEY)
    dd if=/dev/disk/by-id/$USB_STICK of=$ENC_KEY bs=$USB_BSIZE count=$USB_COUNT skip=$USB_SKIP >/dev/null 2>&1
    chmod 400 $ENC_KEY

    $SCRIPT zfsload -s $(dirname $ENC_KEY) -n $(basename $ENC_KEY) -p "$USB_STICK" -v $USB_ZFSVOL || \
        $SCRIPT zfsload -s $(dirname $CONFIG) -v $USB_ZFSVOL
else
    $SCRIPT zfsload -s $(dirname $CONFIG) -v $USB_ZFSVOL
fi

keymanager_zfs.sh

Das Key Management Tool habe ich in einem Forum gefunden: keymanager.sh 

#!/bin/bash
# zfs multiple passwords
# found at: https://forums.gentoo.org/viewtopic-t-1122263-start-0.html
#
# keymanager.sh

case $1 in
   "makekey")
      #default values
      keysize=64
      keyname=$USER
      [ ! -z $SUDOUSER ] && keyname=$SUDOUSER
      store=.
      cnt=1
      ls=1
      for a in "$@"
      do
         let cnt+=1
         case $a in
            -k | --keysize)
               keysize=${!cnt}
               ls=1
            ;;
            -s | --keystore)
               store=${!cnt}
               ls=1
            ;;
            -n | --keyname)
               keyname=${!cnt}
               ls=1
            ;;
            -p | --password)
               pass=${!cnt}
               ls=1
            ;;
            -*)
               echo $1: unknown argument $a
               exit 255
            ;;
            *)
               # if we get here twice in a row, something is wrong
               [ $ls = 0 ] && echo $1: unknown argument $a && exit 254
               ls=0
            ;;
         esac
      done
      mkdir -p $store
      key=`openssl rand -base64 $keysize |tr -d '\n='`
      [ $? != 0 ] && echo "Keygeneration failed" && exit 3
      key="KEY${key:0:$keysize}"
      [ -e ${store}/${keyname} ] && echo Key exists. I will not overwrite ${store}/${keyname} && exit 252
      if [ -z $pass ] ; then
         openssl enc -aes-256-cbc -a -pbkdf2 -iter 1000000 <<< ${key} > ${store}/${keyname}
      else
         openssl enc -aes-256-cbc -a -pbkdf2 -iter 1000000 -pass pass:${pass} <<< ${key} > ${store}/${keyname}
      fi
      [ $? != 0 ] && echo "Encryption failed" && rm ${store}/${keyname} && exit 4
      chmod 600 ${store}/${keyname}
   ;;
   "zfscreate")
      #default values
      keyname=$USER
      [ ! -z $SUDOUSER ] && keyname=$SUDOUSER
      store=.
      opt=""
      cnt=1
      ls=1
      for a in "$@"
      do
         let cnt+=1
         case $a in
            -s | --keystore)
               store=${!cnt}
               ls=1
            ;;
            -n | --keyname)
               keyname=${!cnt}
               ls=1
            ;;
            -p | --password)
               pass=${!cnt}
               ls=1
            ;;
            -v | --volname)
               vol=${!cnt}
               ls=1
            ;;
            -o)
               opt="$opt -o ${!cnt}"
               ls=1
            ;;
            -*)
               echo $1: unknown argument $a
               exit 255
            ;;
            *)
               # if we get here twice in a row, something is wrong
               [ $ls = 0 ] && echo $1: unknown argument $a && exit 254
               ls=0
            ;;
         esac
      done
      [ -z $vol ] && echo $1 needs volumeName. Use -v volumename
      [ ! -r  ${store}/${keyname} ] && echo Key not accessible ${store}/${keyname} && exit 123
      if [ -z $pass ] ; then
         key=`openssl enc -aes-256-cbc -a -pbkdf2 -iter 1000000 -d < ${store}/${keyname}`
      else
         key=`openssl enc -aes-256-cbc -a -pbkdf2 -iter 1000000 -d -pass pass:${pass} < ${store}/${keyname}`
      fi
      [ "KEY" != ${key:0:3} ] && echo Key decrypt failed && exit 10
      defopt=""
      [[ "$opt" != *"encryption="* ]] && defopt="$defopt -o encryption=on"
      [[ "$opt" != *"keyformat="* ]] && defopt="$defopt -o keyformat=passphrase"
      zfs create $defopt $opt $vol <<< $key

   ;;
   "zfsload")
      #default values
      keyname=$USER
      [ ! -z $SUDOUSER ] && keyname=$SUDOUSER
      store=.
      opt=""
      cnt=1
      ls=1
      for a in "$@"
      do
         let cnt+=1
         case $a in
            -s | --keystore)
               store=${!cnt}
               ls=1
            ;;
            -n | --keyname)
               keyname=${!cnt}
               ls=1
            ;;
            -p | --password)
               pass=${!cnt}
               ls=1
            ;;
            -v | --volname)
               vol=${!cnt}
               ls=1
            ;;
            -*)
               echo $1: unknown argument $a
               exit 255
            ;;
            *)
               # if we get here twice in a row, something is wrong
               [ $ls = 0 ] && echo $1: unknown argument $a && exit 254
               ls=0
            ;;
         esac
      done
      [ -z $vol ] && echo $1 needs volumeName. Use -v volumename
      zfs get keystatus |grep $vol |grep " available" && echo Key already loaded, nothing to do && exit 0
      [ ! -r  ${store}/${keyname} ] && echo Key not accessible ${store}/${keyname} && exit 123
      if [ -z $pass ] ; then
         key=`openssl enc -aes-256-cbc -a -pbkdf2 -iter 1000000 -d < ${store}/${keyname}`
      else
         key=`openssl enc -aes-256-cbc -a -pbkdf2 -iter 1000000 -d -pass pass:${pass} < ${store}/${keyname}`
      fi
      [ "KEY" != "${key:0:3}" ] && echo Key decrypt failed && exit 10
      zfs load-key $vol <<< $key
   ;;
   "useradd")
      #default values
      keyname=$USER
      [ ! -z $SUDOUSER ] && keyname=$SUDOUSER
      newkeyname=$USER
      [ ! -z $SUDOUSER ] && newkeyname=$SUDOUSER
      store=.
      opt=""
      cnt=1
      ls=1
      for a in "$@"
      do
         let cnt+=1
         case $a in
            -s | --keystore)
               store=${!cnt}
               ls=1
            ;;
            -n | --keyname)
               keyname=${!cnt}
               ls=1
            ;;
            -p | --password)
               pass=${!cnt}
               ls=1
            ;;
            -m | --newkeyname)
               newkeyname=${!cnt}
               ls=1
            ;;
            -q | --newpass)
               newpass=${!cnt}
               ls=1
            ;;
            -*)
               echo $1: unknown argument $a
               exit 255
            ;;
            *)
               # if we get here twice in a row, something is wrong
               [ $ls = 0 ] && echo $1: unknown argument $a && exit 254
               ls=0
            ;;
         esac
      done
      [ ! -r  ${store}/${keyname} ] && echo Key not accessible ${store}/${keyname} && exit 123
      if [ -z $pass ] ; then
         echo Decrypting key
         key=`openssl enc -aes-256-cbc -a -pbkdf2 -iter 1000000 -d < ${store}/${keyname}`
      else
         key=`openssl enc -aes-256-cbc -a -pbkdf2 -iter 1000000 -d -pass pass:${pass} < ${store}/${keyname}`
      fi
      [ "KEY" != ${key:0:3} ] && echo Key decrypt failed && exit 10

      [ -e ${store}/${newkeyname} ] && echo New key exists. I will not overwrite ${store}/${newkeyname} && exit 252
      if [ -z $newpass ] ; then
         echo Encrypting key
         openssl enc -aes-256-cbc -a -pbkdf2 -iter 1000000 <<< ${key} > ${store}/${newkeyname}
      else
         openssl enc -aes-256-cbc -a -pbkdf2 -iter 1000000 -pass pass:${newpass} <<< ${key} > ${store}/${newkeyname}
      fi
      chmod 600 ${store}/${newkeyname}
   ;;
   *)
      iam=`basename $0`
      echo Usage:
      echo "$iam makekey [-k keySize] [-s keystoreFolder] [-n keyname] [-p password]"
      echo "   Generates at random string (base_64 characters) of length keySize "
      echo "   encrypts it by password, and stores the encrypted string in"
      echo "   folder keystoreFolder."
      echo "   If password is not given, it will be requested from stdin."
      echo "   If no keyname is given, the current username will be used as keyname."
      echo "   If no keystoreFolder is given, the current folder will be used."
      echo "   If no keysize is given, default 64 will be used"
      echo
      echo "$iam zfscreate [-s keystoreFolder] [-n keyname] [-p password] -v volumename [-o zfsoption [-o ....]]"
      echo "   Creates a zfs volume named volumename encrypted with key"
      echo "   previously generated by makekey."
      echo "   Default zfsoption are -o encryption=on -o keyformat=passphrase"
      echo "   Additional zfsoptions may be specified."
      echo "   Password is used to decrypt key. If password is not given, it "
      echo "   will be requested from stdin."
      echo "   If no keyname is given, the current username will be used as keyname."
      echo "   If no keystoreFolder is given, the current folder will be used."
      echo
      echo "$iam zfsload [-s keystoreFolder] [-n keyname] [-p password] -v volumename"
      echo "   Decrypts key previously generated by makekey and executes zfs load-key"
      echo "   Password is used to decrypt key. If password is not given, it "
      echo "   will be requested from stdin."
      echo "   If no keyname is given, the current username will be used as keyname."
      echo "   If no keystoreFolder is given, the current folder will be used."
      echo
      echo "$iam useradd [-s keystoreFolder] [-n keyname] [-p password] [-m newkeyname] [-q newpass] "
      echo "   Makes a key previously generated by makekey available to anotheruser."
      echo "   That is, decrypts the key saved under keyname using password, then"
      echo "   saves it under newkeyname encryoted by using newpass"
      echo "   Password is used to decrypt key. If password is not given, it "
      echo "   will be requested from stdin."
      echo "   Newpassw is used to encrypt key. If newpass is not given, it "
      echo "   will be requested from stdin."
      echo "   If no keyname is given, the current username will be used as keyname."
      echo "   If no newkeyname is given, the current username will be used as keyname."
      echo "   If no keystoreFolder is given, the current folder will be used."
   ;;
esac
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