Namestite in nastavite CentOS 7 za oddaljeno odklepanje LVM na šifriranju diska LUKS z uporabo SSH

LUKS (Linux Unified Key Setup) je eden od različnih formatov šifriranja diska, ki je na voljo za Linux in je neodvisen od platforme. Ta vadnica vam bo zagotovila korenske in izmenjalne particije znotraj nosilca LVM (Linux Volume Manager), ki se nahaja znotraj šifrirane particije LUKS. Ta vadnica vam omogoča tudi odklepanje particije LUKS na daljavo z uporabo poenostavljenega strežnika SSH z uporabo katerega koli združljivega odjemalskega programa SSH.

Predpogoji

• Primerek strežnika knjižnice CentOS 7 x64 Minimal ISO Library.
• Uporabnik sudo .
• Javni ključ(i) SSH .
• Dracut-Crypt-SSH .

1. korak: Nastavitev okolja

Na strani Razmestitev strežnikov naredite naslednje:

• V Server Locationrazdelku izberite lokacijo strežnika .
• Izberite CentOS7pod ISO Libraryzavihkom Server Typerazdelka.
• V razdelku izberite specifikacije strojne opreme, ki jih potrebujete Server Size.
• Kliknite Deploy Nowgumb.

Uporabite View Consolemožnost za dostop do primerka VPS prek konzole noVNC.

2. korak: Zaženite namestitveni program za besedilni način CentOS 7

Izberite Install CentOS Linux 7možnost.

Pritisnite Tabtipko.

Vnesite textpo, vmlinuz initrd=initrd.img inst.stage2=hd:LABEL=CentOS\x207\x20\86_64 quiettako da izgleda takole vmlinuz initrd=initrd.img inst.stage2=hd:LABEL=CentOS\x207\x20\86_64 quiet textin pritisnite Entertipko.

VPS se bo zdaj zagnal v namestitveni program CentOS v besedilnem načinu. V konzoli noVNC boste videli zaslon, kot je prikazano na spodnji sliki.

3. korak: Nastavite LVM na LUKS Full Disk Encryption

S Alt + Right Arrow Keykombinacijo se pomaknite do konzole TTY2 in vnesite ukaze v ukazno vrstico.

Vnesite spodnje ukaze, da ustvarite particijo, ki vsebuje zagonski nalagalnik GRUB2, nešifrirano /bootparticijo in primarno particijo, ki bo vsebovala particijo LUKS.

parted -a opt -s /dev/vda mklabel gpt
parted -s /dev/vda unit mb
parted -s /dev/vda mkpart primary 1 3
parted -s /dev/vda name 1 grub
parted -s /dev/vda set 1 bios_grub on
parted -s /dev/vda mkpart primary 3 259
parted -s /dev/vda name 2 boot
parted -s /dev/vda mkpart primary 259 100%
parted -s /dev/vda name 3 root

Vnesite naslednji ukaz, da prikažete postavitev particije.

parted -s /dev/vda print

Nato napolnite imenovano rootfsparticijo s psevdo-naključnimi podatki. To bo trajalo nekaj več kot pol ure.

dd if=/dev/urandom of=/dev/vda3 bs=1M status=progress

V CentOS 7 cryptsetupukazi uporabljajo privzeto šifro aes-xts-plain64, privzeto velikost ključa 256 bitov in privzeto razpršitev SHA1. Namesto tega bo particija LUKS ustvarjena z varnejšo šifro Serpent, z velikostjo ključa 512 bitov in s hashom Whirlpool.

cryptsetup luksFormat /dev/vda3 -c serpent-xts-plain64 -h whirlpool -s 512

Vnesite odgovore, ko boste pozvani z naslednjimi poizvedbami, nato pritisnite Entertipko:

• Ali si prepričan? (Vnesite velike črke da):YES
• Vnesite geslo: strong-password
• Preverite geslo: strong-password

Izbirno: varnostno kopirajte glavo particije LUKS

Opozorilo To bo omogočilo root prijavo in kopiranje brez poziva za geslo. Ukinite ta strežnik SSH, ko pridobite /tmp/luks-header-backup.imgdatoteko.

Za varno shranjevanje shranite kopijo glave particije LUKS. To zagotavlja, da če je glava vaše LUKS particije nekako poškodovana, jo je mogoče obnoviti. Če je glava poškodovana brez delujoče varnostne kopije, so vaši podatki za vedno izgubljeni.

cryptsetup luksHeaderBackup /dev/vda3 --header-backup-file /tmp/luks-header-backup.img

Če želite kopirati /tmp/luks-header-backup.imgdatoteko s strežnika, je treba začasno zagnati strežnik SSH z uporabo izvedljive varne kopije scpna odjemalskem gostitelju, da jo pridobi.

Vnesite spodnji ukaz, da ustvarite gostiteljske ključe SSH.

sshd-keygen

Vnesite spodnji ukaz, da ustvarite /etc/ssh/sshd_configdatoteko.

cp /etc/ssh/sshd_config.anaconda /etc/ssh/sshd_config

Vnesite spodnji ukaz, da uredite /etc/ssh/sshd_configdatoteko.

vi /etc/ssh/sshd_config

Za urejanje datoteke pritisnite Inserttipko in s puščičnimi tipkami se pomaknite do odsekov datoteke, ki jih je treba urediti.

V prvi vrstici spremenite številko v Port 22iz privzetega v 22naključno število po vaši izbiri med 1025in 65535. (Primer: vrata 25782)

Pomaknite se navzdol do vrstice številka trinajst, pritisnite Endtipko in pritisnite Entertipko.

V naslednji vrstici dodajte HostKey /etc/ssh/ssh_host_ed25519_keyin pritisnite Entertipko.

V naslednji vrstici dodajte HostKey /etc/ssh/ssh_host_rsa_keyin pritisnite Entertipko.

Pritisnite Esctipko, vnesite :wqin pritisnite Entertipko, da shranite datoteko.

Privzeti omrežni vmesnik eth0potrebuje naslov IP. Vnesite spodnji ukaz, da eth0omrežnemu vmesniku dodelite naslov IP, ki je naveden za vaš primerek .

dhclient

Vnesite naslednji ukaz, da prikažete dodeljeni naslov IP. Naslov IP bo naveden takoj za inetin pred netmask. (Primer: inet 192.0.2.1omrežna maska)

ifconfig eth0

Vnesite naslednji ukaz, da zaženete strežnik SSH.

/usr/sbin/sshd

Če uporabljate scpukaz iz ukazne vrstice na odjemalskem računalniku, uporabite spodnji ukaz kot predlogo za pridobitev /tmp/luks-header-backup.imgdatoteke. Zamenjajte 25782z dejansko številko vrat, dodeljeno v /etc/ssh/sshd_config. Zamenjajte 192.0.2.1z dejansko dodeljenim naslovom IP.

scp -P 25782 [email protected]:/tmp/luks-header-backup.img .

Po pridobitvi luks-header-backup.imgdatoteke takoj ukinite strežnik SSH, tako da v okno konzole noVNC vnesete spodnji ukaz.

killall sshd

Odprite particijo LUKS, da nastavite fizični nosilec LVM, ki bo v notranjosti.

cryptsetup luksOpen /dev/vda3 centos

Vnesite prej ustvarjeno geslo, da odprete particijo LUKS, ko ste pozvani, nato pritisnite Entertipko.

Vnesite geslo za /dev/vda3:strong-password

Spodaj vnesite naslednji ukaz:

ls /dev/mapper

Vsebuje naslednje datoteke z imenom centos, control, live-basein live-rw. To centosje particija LUKS.

Vnesite spodnji ukaz, da ustvarite fizični nosilec LVM.

pvcreate /dev/mapper/centos

Ko bo uspešno, boste prejeli naslednje sporočilo:

Physical volume "/dev/mapper/centos" successfully created

Vnesite spodnji ukaz, da ustvarite skupino nosilcev LVM.

vgcreate ssd /dev/mapper/centos

Ko bo uspešno, boste prejeli naslednje sporočilo:

Volume group "ssd" successfully created

Vnesite spodnji ukaz, da ustvarite logični nosilec LVM za izmenjalno particijo. Uporabite zdravo presojo, da ustvarite izmenjalno particijo potrebne velikosti (-L = velikost nosilca) na podlagi vašega primerka VPS.

lvcreate -L 1G -n swap ssd

Ko bo uspešno, boste prejeli naslednje sporočilo:

Logical volume "swap" created

Vnesite spodnji ukaz, da ustvarite logični nosilec LVM za korensko particijo. S tem boste porabili preostali prosti prostor, medtem ko boste rezervirali pet odstotkov (5 %) za vsebovanje posnetkov LVM vaših logičnih nosilcev, če se tako odločite.

lvcreate -l 95%FREE -n root ssd

Ko bo uspešno, boste prejeli naslednje sporočilo:

Logical volume "root" created

Prikažite fizični volumen LVM.

pvdisplay

V konzoli noVNC boste videli besedilo, podobno tistemu, ki je prikazano na spodnji sliki.

Prikažite skupino nosilcev LVM.

vgdisplay

V konzoli noVNC boste videli besedilo, podobno tistemu, ki je prikazano na spodnji sliki.

Prikažite logične nosilce LVM.

lvdisplay

V konzoli noVNC boste videli besedilo, podobno tistemu, ki je prikazano na spodnji sliki.

Vnesite spodnji ukaz, da deaktivirate skupino nosilcev LVM. To je treba dokončati, da lahko cryptsetupv naslednjem koraku zaprete particijo LUKS.

vgchange -a n

Ko bo uspešno, boste prejeli naslednje sporočilo:

0 logical volume(s) in volume group "ssd" now active

Zaprite glasnost LUKS.

cryptsetup luksClose centos

Spodaj vnesite naslednji ukaz:

ls /dev/mapper

It will contain the following files named control, live-base and live-rw. The centos file, containing the LUKS partition, will be missing to ensure that that it was closed properly.

Type reboot and press the Enter key to reboot.

Step 4: Start The CentOS 7 GUI Mode Installer

Select the Install CentOS Linux 7 option and press the Enter key.

The VPS will now boot into the GUI mode CentOS installer. You will see a screen in the noVNC console like pictured in the image below. Select Install CentOS 7 (1) and press the Enter key.

On the WELCOME TO CENTOS 7 screen, click the blue Continue button (1).

Attention If you're not using the default language of English and the locale of the United States, input your language in the search bar (1). Click on the language (2) and the appropriate locale (3) associated with it. When satisfied, click the blue Continue button (4).

On the INSTALLATION SUMMARY screen, click on INSTALLATION DESTINATION (Automatic partitioning selected) (1) under SYSTEM.

On the INSTALLATION DESTINATION screen, select the I will configure partitioning (1) option under Other Storage Options (Partitioning) and click the blue Done button (2) at the top left of the screen.

On the MANUAL PARTITIONING screen, click on the Unknown expandable accordion (1). It will reveal three partitions named BIOS Boot (vda1), Unknown (vda2) and Encrypted (LUKS) (vda3).

With the BIOS Boot partition highlighted in blue (1), select the checkbox option of Reformat (2) next to the File System: accordion and click the Update Settings button (3).

Click on the Unknown partition (1) so that it is highlighted in blue. Select the checkbox option of Reformat (2) next to the File System: accordion. Select ext2 in the File System: accordion (3), enter /boot in the text field (4) under Mount Point:, enter boot in the text field (5) under Label: and click the Update Settings button (6).

Click on the Encrypted (LUKS) partition (1) so that it is highlighted in blue. Enter the passphrase you created for LUKS partition in Step 3: Setup LVM On LUKS Full Disk Encryption in the Passphrase: text field (2) and click the Unlock button (3).

A new Unknown expandable accordion (1) will appear. It will reveal two partitions named Unknown (ssd-root) and Unknown (ssd-swap).

With the Unknown (ssd-root) partition (1) highlighted in blue, select the checkbox option of Reformat (2) next to the File System: accordion. Select xfs in the File System: accordion (3), enter / in the text field (4) under Mount Point:, enter root in the text field (5) under Label: and click the Update Settings button (6).

Click on the Unknown (ssd-swap) (1) partition so that it is highlighted in blue. Select the checkbox option of Reformat (2) next to the File System: accordion. Select swap in the File System: accordion (3), enter swap in the text field (4) under Label: and click the Update Settings button (5).

Click the blue Done button (1) at the top left of the screen.

A box named SUMMARY OF CHANGES will pop up. Click the Accept Changes button (1). This will bring you back to the WELCOME TO CENTOS 7 screen.

Click on NETWORK & HOST NAME (Not connected) (1) under SYSTEM.

On the NETWORK & HOST NAME screen, move the slider (1), next to the right of Ethernet(eth0) field, from the OFF position to the ON position. If you want to use a custom hostname instead of the default (192.0.2.1.vultr.com) in the Host name: text box (2), change it. Click the blue Done button (3) at the top left of the screen. This will bring you back to the WELCOME TO CENTOS 7 screen.

When you are satisfied with the options on the WELCOME TO CENTOS 7 screen, click the blue Begin Installation button (1).

On the CONFIGURATION screen, click on ROOT PASSWORD (Root password is not set) (1) under USER SETTINGS.

On the ROOT PASSWORD screen, enter a strong password in both the Root Password: (1) and Confirm: (2) text fields. Click the blue Done button (3) at the top left of the screen. This will bring you back to the CONFIGURATION screen.

On the CONFIGURATION screen, click on USER CREATION (No user will be created) (1) under USER SETTINGS.

On the CREATE USER screen, enter your full name in the Full name text field (1), an username in the User name text field (2), a strong password in both the Password (3) and Confirm password (4) text fields. Click on the Advanced... button (5).

A box named ADVANCED USER CONFIGURATION will pop up. In the Add user to the following groups: text field (1) under Group Membership, enter wheel and click the Save Changes button (2).

Click the blue Done button (1) at the top left of the screen.

The post-installation process will now commence. It will take a few minutes to complete. When it is finished, click on the blue Reboot button (1) to reboot your VPS instance.

Navigate back to the VULTR Server Management Screen. Click on the Settings link at the top. Click on Custom ISO on the menu on the left side. On the Custom ISO page, click on the Remove ISO button to unmount the ISO and reboot into your CentOS 7 VPS instance. Click the OK button when prompted and the VPS instance will reboot.

Navigate back to the View Console window to access the VPS instance via the noVNC console. Refresh the window if noVNC has disconnected.

You will be prompted to enter the passphrase (Example: Please enter passphrase for disk primary (luks-xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx)!:) you created for LUKS partition in Step 3: Setup LVM On LUKS Full Disk Encryption. Enter the passphrase and press the Enter key.

You will then be presented with the console login prompt. You can now close the noVNC console window.

Step 5: Update The System

Log in via SSH with a regular user and update the system as follows.

sudo yum install epel-release -y
sudo yum clean all && sudo yum update -y

Step 6: Install Dracut-Crypt-SSH

While still logged in as a regular user, type the following commands below to install dracut-crypt-ssh.

sudo yum install wget -y
sudo wget -O /etc/yum.repos.d/rbu-dracut-crypt-ssh-epel-7.repo https://copr.fedorainfracloud.org/coprs/rbu/dracut-crypt-ssh/repo/epel-7/rbu-dracut-crypt-ssh-epel-7.repo
sudo yum install dracut-crypt-ssh -y

Type the following command below to install the nano editor to ease editing of files.

sudo yum install nano -y

You will need to edit the default grub file located in /etc/default/grub.

sudo nano /etc/default/grub

Insert rd.neednet=1 ip=dhcp between GRUB_CMDLINE_LINUX="crashkernel=auto and rd.luks.uuid=luks-xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.

Save the file by entering the following keyboard combinations. Press the Ctrl + x keys, press the y key and press the Enter key.

Regenerate you GRUB configuration file by type the command below.

sudo grub2-mkconfig -o /etc/grub2.cfg 

Backup the original /etc/dracut.conf.d/crypt-ssh.conf by typing the following command below.

sudo mv /etc/dracut.conf.d/crypt-ssh.conf /etc/dracut.conf.d/crypt-ssh.conf.orig

Create a new /etc/dracut.conf.d/crypt-ssh.conf file by typing the following command below.

sudo nano /etc/dracut.conf.d/crypt-ssh.conf

Copy and paste the following text below into the nano editor.

dropbear_acl="/etc/dropbear/keys/authorized_keys"
dropbear_ecdsa_key="/etc/dropbear/keys/ssh_ecdsa_key"
dropbear_rsa_key="/etc/dropbear/keys/ssh_rsa_key"

Create the directory keys under /etc/dropbear/, with the necessary directory permissions, that will hold the authorized_keys, ssh_ecdsa_key and ssh_rsa_key files.

sudo mkdir /etc/dropbear/keys/; sudo chmod /etc/dropbear/keys/

Generate the ssh_ecdsa_key and ssh_rsa_key files with the ssh_keygen program by typing the following commands below. Press the Enter key twice, for each command, when prompted for passphrases.

sudo ssh-keygen -t ecdsa -f /etc/dropbear/keys/ssh_ecdsa_key
sudo ssh-keygen -t rsa -f /etc/dropbear/keys/ssh_rsa_key

Change the file permissions on ssh_ecdsa_key, ssh_ecdsa_key.pub, ssh_rsa_key and ssh_rsa_key.pub by typing the command below.

sudo chmod 400 /etc/dropbear/keys/*_key; sudo chmod 444 /etc/dropbear/keys/*.pub

Generate public keys using the How Do I Generate SSH Keys? tutorial, found at the beginning of the tutorial under Prerequisites, for your prospective client operating system.

Copy and paste all the text in the public key into the /etc/dropbear/keys/authorized_keys file using the nano program by typing the command below.

sudo nano /etc/dropbear/keys/authorized_keys

You must first build the initramfs and any subsequent update of the dracut-crypt-ssh configuration. Type the following command below for the initial build of the initramfs.

sudo dracut -f

Once that's complete, your CentOS 7 install is set up to listen for your SSH client to connect and allow you to unlock the LUKS partition using your passphrase. You may now reboot your CentOS 7 instance by typing the command below.

sudo reboot

V vaših odjemalskih sistemih si oglejte razdelke 3.3. Unlocking the volumes interactivelyin 3.4. Unlocking using theodklenite commandstran Dracut-Crypt-SSH GitHub, da izsilite poziv za geslo ali uporabite unlockukaz, da odprete svojo particijo LUKS iz odjemalca SSH.