[cipher][archlinux][disk encryption][btrfs] 磁盘分区加密 + btrfs

科普链接：https://wiki.archlinux.org/index.php/Disk_encryption

前面的链接关于硬盘加密，讲了几种，基本上就是选dm-crypt with LUKS

在grub中，解密根分区以及/boot分区。

dm-crypt文档：https://wiki.archlinux.org/index.php/Dm-crypt

使用 dm-crypt加密一个非根分区。https://wiki.archlinux.org/index.php/Dm-crypt/Encrypting_a_non-root_file_system

dm-crypt 的两种加密方式： PLAIN， LUKS（Linux Unified Key Setup）。

具体什么区别我也不太知道，简单来说就是LUKS在文件系统（硬盘分区？）里存储了与加密信息加密方式相关的元数据。而PLAIN中没有。LUKS是dm-crypt的默认方式。

一堆破文档，都不及man手册讲的清楚。

DESCRIPTION
       cryptsetup  is  used  to  conveniently setup dm-crypt managed device-mapper mappings. These include plain dm-crypt volumes and
       LUKS volumes. The difference is that LUKS uses a metadata header and can hence offer more features than plain dm-crypt. On the
       other hand, the header is visible and vulnerable to damage.

这个man，写的这么好，在我看过的man里边可以排前三。

/home/tong/bin [tong@T7] [:]
> man cryptsetup

一： 弄了台虚拟机做实验先：

[root@t206 arch-crypt]# qemu-system-x86_64 -vnc 0.0.0.0: --enable-kvm -smp  -m 1G -drive file=disk.qcow2,if=virtio -net bridge -net nic,model=virtio -cdrom ../iso/archlinux-2017.05.-x86_64.iso 

二： 加密非根分区

1.  格式化LUKS分区

root@archiso ~ # cryptsetup luksFormat /dev/vda

WARNING!
========
This will overwrite data on /dev/vda irrevocably.

Are you sure? (Type uppercase yes): YES
Enter passphrase:
Verify passphrase:
cryptsetup luksFormat /dev/vda  .00s user .01s system % cpu 12.157 total
root@archiso ~ # 

后边还能加一个参数 keyfile。意思是将keyfile里边的内容作为密码。

2.  挂载加密分区（解密）

root@archiso ~ # cryptsetup open /dev/vda vd_root
Enter passphrase for /dev/vda:
root@archiso ~ # ll /dev/mapper/vd_root
lrwxrwxrwx  root root  Jun   : /dev/mapper/vd_root -> ../dm-

3.  初始化文件系统

 root@archiso ~ # mkfs.xfs /dev/mapper/vd_root           

4.  挂载使用

root@archiso ~ # mount /dev/mapper/vd_root mnt
root@archiso ~ # ll
total
-rw-r--r--  root root  May   : install.txt
drwxr-xr-x  root root     Jun   : mnt
root@archiso ~ # cd mnt
root@archiso ~/mnt # ll
total
root@archiso ~/mnt # touch
root@archiso ~/mnt # touch txt
root@archiso ~/mnt # vim txt
root@archiso ~/mnt # cat txt 

root@archiso ~/mnt # ls
  txt
root@archiso ~/mnt # ll
total
-rw-r--r--  root root  Jun   :
-rw-r--r--  root root  Jun   : txt
root@archiso ~/mnt # cd ..

5. 卸载关闭

root@archiso ~ # umount mnt
root@archiso ~ # cryptsetup close vd_root
root@archiso ~ # ll /dev/mapper
total
crw-------  root root ,  Jun   : control
root@archiso ~ # 

三， 加密全系统

https://wiki.archlinux.org/index.php/Dm-crypt/Encrypting_an_entire_system

有多种方式，以及包括boot分区加密等。内容很多

boot分区，MBR加密：https://wiki.archlinux.org/index.php/Dm-crypt/Specialties#Securing_the_unencrypted_boot_partition

chkboot（检查分区是否被串改？）

首先，我选用简单的方法，在LUKS上创建btrfs。查看上述文档的btrfs章节。

btrfs的详细内容，branch到这里：http://www.cnblogs.com/hugetong/p/6934247.html

全系统加密的关键在于，initrd，grub，boot partition，以及kernel。

分区什么的，与非根分区没什么区别，不再叙述。

还是有区别的，这块盘，我需要分出boot partition，swap partition，如果是uEFI的话，还有ESP分区。

有关 parted的unit问题 https://www.gnu.org/software/parted/manual/parted.html#unit

1.  分区表使用 GPT

root@archiso ~ # parted /dev/vda
GNU Parted 3.2
Using /dev/vda
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) mktable gpt

2.  创建BIOS grub分区

　　bios_grub分区只需要31KiB，但是为了对齐以及扩展，我们用1MiB

https://www.gnu.org/software/grub/manual/html_node/BIOS-installation.html

(parted) mkpart fat32 1MiB 2MiB
(parted) set  bios_grub on
(parted) print
Model: Virtio Block Device (virtblk)
Disk /dev/vda: 20971520kiB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags: 

Number  Start    End      Size     File system  Name  Flags
       1024kiB  2048kiB  1024kiB                     bios_grub

(parted)                               

3. 创建boot分区。挂载根分区前的所有内容，都在这个分区里，我们选择1G的大小。

　　A suggested size for /boot is 200 MiB unless using UEFI, in which case greater than 512 MiB is needed.

(parted) mkpart ext4 2MiB 1026MiB
(parted) print
Model: Virtio Block Device (virtblk)
Disk /dev/vda: 20971520kiB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags: 

Number  Start    End         Size        File system  Name  Flags
       1024kiB  2048kiB     1024kiB                        bios_grub
       2048kiB  1050624kiB  1048576kiB

(parted)                                           

4. swap分区。 时至今日，swap分区的大小已经没有要求了。要求只来自suspend and hibernate。

　　文件 /sys/power/image_size 中配置了系统对于hibernate image大小的限制。默认为RAM大小的2/5

　　https://wiki.archlinux.org/index.php/Partitioning#Swap

　　https://wiki.archlinux.org/index.php/Power_management/Suspend_and_hibernate#Hibernation

(parted) mkpart primary linux-swap 1026MiB 3074MiB
(parted) print
Model: Virtio Block Device (virtblk)
Disk /dev/vda: 20480MiB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags: 

Number  Start    End      Size     File system     Name  Flags
       .00MiB  .00MiB  .00MiB                        bios_grub
       .00MiB  1026MiB  1024MiB
       1026MiB  3074MiB  2048MiB  linux-swap(v1)

(parted)                                           

5.  剩下的空间做成 crypt-LUKS + btrfs

(parted) mkpart primary 3074MiB %
(parted) print
Model: Virtio Block Device (virtblk)
Disk /dev/vda: 20480MiB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags: 

Number  Start    End       Size      File system     Name  Flags
       .00MiB  .00MiB   .00MiB                         bios_grub
       .00MiB  1026MiB   1024MiB
       1026MiB  3074MiB   2048MiB   linux-swap(v1)
       3074MiB  20479MiB  17405MiB

(parted)                        

初始化各分区文件系统，与前文操作一至

root@archiso ~ # mkfs.fat /dev/sda1
mkfs.fat 4.1 (--)
mkfs.fat: unable to open /dev/sda1: No such file or directory
 root@archiso ~ # mkfs.fat /dev/vda1                                                                                                 :(
mkfs.fat 4.1 (--)
root@archiso ~ # mkfs.fat /dev/vda2
mkfs.fat 4.1 (--)
root@archiso ~ # mkswap /dev/vda3
Setting up swapspace version , size =  GiB ( bytes)
no label, UUID=3b11937b-85fb-4c8a-8f8f-97e75097b4e1
root@archiso ~ # cryptsetup luksFormat /dev/vda4 

WARNING!
========
This will overwrite data on /dev/vda4 irrevocably.

Are you sure? (Type uppercase yes): YES
Enter passphrase:
Verify passphrase:
cryptsetup luksFormat /dev/vda4  .00s user .03s system % cpu 20.180 total
root@archiso ~ # cryptsetup luksFormat /dev/vda4

WARNING!
========
This will overwrite data on /dev/vda4 irrevocably.

Are you sure? (Type uppercase yes): YES
Enter passphrase:
Verify passphrase:
Passphrases do not match.
 root@archiso ~ # cryptsetup luksFormat /dev/vda4                                                                                    :(

WARNING!
========
This will overwrite data on /dev/vda4 irrevocably.

Are you sure? (Type uppercase yes): YES
Enter passphrase:
Verify passphrase:
root@archiso ~ # cryptsetup luksFormat /dev/vda4

WARNING!
========
This will overwrite data on /dev/vda4 irrevocably.

Are you sure? (Type uppercase yes): YES
Enter passphrase:
Verify passphrase:
root@archiso ~ #
root@archiso ~ #
root@archiso ~ #
root@archiso ~ # parted -l /dev/vda
Warning: Unable to open /dev/sr0 read-write (Read-only file system).  /dev/sr0
has been opened read-only.
Model: QEMU QEMU DVD-ROM (scsi)
Disk /dev/sr0: 504MB
Sector size (logical/physical): 2048B/2048B
Partition Table: msdos
Disk Flags: 

Number  Start  End    Size   Type     File system  Flags
       336kB  269MB  268MB  primary               esp

Model: Virtio Block Device (virtblk)
Disk /dev/vda: .5GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags: 

Number  Start   End     Size    File system     Name       Flags
       1049kB  2097kB  1049kB                  bios_grub  bios_grub
       2097kB  1076MB  1074MB  fat32           boot
       1076MB  3223MB  2147MB  linux-swap(v1)  swap
       3223MB  .5GB  .3GB                  root

root@archiso ~ # 

挂载crypt分区后，创建btrfs文件系统。

root@archiso ~ # cryptsetup open --type luks /dev/vda4 crypt_root
Enter passphrase for /dev/vda4:
root@archiso ~ # mkdir mnt
root@archiso ~ # mkfs.btrfs -L root /dev/mapper/crypt_root                                                                          :(
btrfs-progs v4.10.2
See http://btrfs.wiki.kernel.org for more information.

Label:              root
UUID:               cd3b27fb-f257-4afc-b402-fec0550d014e
Node size:
Sector size:
Filesystem size:    .00GiB
Block group profiles:
  Data:             single            .00MiB
  Metadata:         DUP               .00GiB
  System:           DUP               .00MiB
SSD detected:       no
Incompat features:  extref, skinny-metadata
Number of devices:
Devices:
   ID        SIZE  PATH
        .00GiB  /dev/mapper/crypt_root

root@archiso ~ # mount /dev/mapper/crypt_root mnt
root@archiso ~ # btrfs subvolume create mnt/top                                                                                     :(
Create subvolume 'mnt/top'
root@archiso ~/mnt # cd top
root@archiso ~/mnt/top # mkdir snapshot
root@archiso ~/mnt/top # btrfs subvolume create root
Create subvolume './root'
root@archiso ~/mnt/top # btrfs subvolume create home
Create subvolume './home'
root@archiso ~/mnt/top # ll
total
drwxr-xr-x  root root  Jun   : home
drwxr-xr-x  root root  Jun   : root
drwxr-xr-x  root root  Jun   : snapshot
root@archiso ~/mnt/top # cd ..
root@archiso ~/mnt # ls
top
root@archiso ~/mnt # cd ..
root@archiso ~ # ls
install.txt  mnt
root@archiso ~ # btrfs subvolume list mnt
ID  gen  top level  path top
ID  gen  top level  path top/root
ID  gen  top level  path top/home
root@archiso ~ #
root@archiso ~ #
root@archiso ~ # umount mnt
root@archiso ~ # cryptsetup close /dev/mapper/crypt_root
root@archiso ~ # 

6. 安装系统

6.1 安装目录树结构挂起来

root@archiso ~ # parted -l /dev/sda
Number  Start   End     Size    File system     Name       Flags
       1049kB  2097kB  1049kB                  bios_grub  bios_grub
       2097kB  1076MB  1074MB  fat32           boot
       1076MB  3223MB  2147MB  linux-swap(v1)  swap
       3223MB  .5GB  .3GB                  root
root@archiso ~ # btrfs subvolume list mnt
ID  gen  top level  path top
ID  gen  top level  path top/root
ID  gen  top level  path top/home
root@archiso ~ # mount -o compress=lzo,subvol=top/root /dev/mapper/crypt_root mnt
root@archiso ~ # mkdir mnt/boot
root@archiso ~ # mkdir mnt/home
root@archiso ~ # mount -o compress=lzo,subvol=top/home /dev/mapper/crypt_root mnt/home
root@archiso ~ # mount /dev/vda2 mnt/boot
root@archiso ~ # swapon /dev/vda3 

6.2  设置键盘

6.3  查看boot mode

6.4  设置时间

root@archiso ~ # ll /etc/localtime
lrwxrwxrwx  root root  May   : /etc/localtime -> /usr/share/zoneinfo/UTC
root@archiso ~ # rm /etc/localtime
root@archiso ~ # ln -s /usr/share/zoneinfo/Asia/Shanghai /etc/localtime
root@archiso ~ # timedatectl set-ntp true
root@archiso ~ # timedatectl status
      Local time: Sat -- :: CST
  Universal time: Sat -- :: UTC
        RTC time: Sat -- ::
       Time zone: Asia/Shanghai (CST, +)
 Network time on: yes
NTP synchronized: no
 RTC in local TZ: no
root@archiso ~ # date
Sat Jun   :: CST
root@archiso ~ # 

6.5  修改 /etc/pacman.d/mirrorlist

6.6  strap 根分区

root@archiso ~ # pacstrap mnt base

6.7  生成分区挂载信息

root@archiso ~ # genfstab -U mnt >> mnt/etc/fstab 

6.8  change root

root@archiso ~ # arch-chroot mnt
[root@archiso /]# ll

6.9  改时区

[root@archiso /]# ln -sf /usr/share/zoneinfo/Asia/Shanghai /etc/localtime 
[root@archiso /]# hwclock --systohc

6.10  本地化 localizations

[root@archiso /]# vi /etc/locale.gen
[root@archiso /]# locale-gen
Generating locales...
  en_US.UTF-... done
  zh_CN.GBK... done
  zh_CN.UTF-... done
  zh_CN.GB2312... done
Generation complete.
[root@archiso /]# echo "LANG=en_US.UTF-8" >> /etc/locale.conf

6.11  config network with netctl

[root@archiso netctl]# cp examples/ethernet-static lan0
[root@archiso netctl]# vi lan0
[root@archiso netctl]# netctl list
* lan0

6.12 初始化 initramfs

根分区是加密的，ramfs 复杂解密，所以关于加密的所有特异性配置，都在这里了。

[root@archiso ~]# vim /etc/mkinitcpio.conf 
[root@archiso etc]# diff mkinitcpio.conf mkinitcpio.conf.bak  
52c52
< HOOKS="base udev autodetect modconf keyboard keymap block encrypt filesystems fsck"
---
> HOOKS="base udev autodetect modconf block filesystems keyboard fsck"
[root@archiso etc]# 

mkinitcpio 时有一个错误

==> ERROR: file not found: `fsck.btrfs'

安装 btrfs-progs, 它默认不再base里。

[root@archiso etc]# pacman -S btrfs-progs

制作 initramfs

[root@archiso etc]# mkinitcpio -p linux
==> Building image from preset: /etc/mkinitcpio.d/linux.preset: 'default'
  -> -k /boot/vmlinuz-linux -c /etc/mkinitcpio.conf -g /boot/initramfs-linux.img
==> Starting build: 4.11.--ARCH
  -> Running build hook: [base]
  -> Running build hook: [udev]
  -> Running build hook: [autodetect]
  -> Running build hook: [modconf]
  -> Running build hook: [keyboard]
  -> Running build hook: [keymap]
  -> Running build hook: [block]
  -> Running build hook: [encrypt]
  -> Running build hook: [filesystems]
  -> Running build hook: [keyboard]
  -> Running build hook: [fsck]
==> Generating module dependencies
==> Creating gzip-compressed initcpio image: /boot/initramfs-linux.img
==> Image generation successful
==> Building image from preset: /etc/mkinitcpio.d/linux.preset: 'fallback'
  -> -k /boot/vmlinuz-linux -c /etc/mkinitcpio.conf -g /boot/initramfs-linux-fallback.img -S autodetect
==> Starting build: 4.11.--ARCH
  -> Running build hook: [base]
  -> Running build hook: [udev]
  -> Running build hook: [modconf]
  -> Running build hook: [keyboard]
  -> Running build hook: [keymap]
  -> Running build hook: [block]
==> WARNING: Possibly missing firmware for module: wd719x
==> WARNING: Possibly missing firmware for module: aic94xx
  -> Running build hook: [encrypt]
  -> Running build hook: [filesystems]
  -> Running build hook: [keyboard]
  -> Running build hook: [fsck]
==> Generating module dependencies
==> Creating gzip-compressed initcpio image: /boot/initramfs-linux-fallback.img
==> Image generation successful
[root@archiso etc]# 

根据：https://wiki.archlinux.org/index.php/Btrfs#Corruption_recovery 可以选择性添加如下配置：

14c14
< BINARIES="/usr/bin/btrfs"
---
> BINARIES=""

6.13 设置 password

[root@archiso etc]# passwd
New password:
Retype new password:
passwd: password updated successfully
[root@archiso etc]# 

6.14 安装 boot loader

https://wiki.archlinux.org/index.php/GRUB

[root@archiso etc]# pacman -S grub

[root@archiso etc]# grub-install --target=i386-pc /dev/vda
Installing for i386-pc platform.
Installation finished. No error reported.
[root@archiso etc]# 

https://wiki.archlinux.org/index.php/GRUB#Generate_the_main_configuration_file

[root@archiso ~]# vim /etc/default/grub

https://wiki.archlinux.org/index.php/Dm-crypt/System_configuration#Boot_loader

[root@archiso ~]# diff /etc/default/grub /etc/default/grub.bak
4c4
< GRUB_CMDLINE_LINUX_DEFAULT="cryptdevice=UUID=38312920-93be-4ff6-ba88-e53505fcfb93:vd_root resume=UUID=3b11937b-85fb-4c8a-8f8f-97e75097b4e1 quiet"
---
> GRUB_CMDLINE_LINUX_DEFAULT="quiet"
[root@archiso ~]# 

[root@archiso ~]# vim /boot/grub/grub.cfg

7  重启

reboot