RHEL：無密碼的 FDE - 從分區上的密鑰啟動

我正在嘗試在 RHEL 7.2 上使用 LVM 加密我的作業系統，並通過使用未加密分區上的密鑰啟動它而無需輸入密碼。

LV    VG    Attr     LSize  Pool Origin Data%  Meta%  Move Log Cpy%Sync Convert
home rhel -wi-ao---- 22.35g                                                 
root rhel -wi-ao---- 27.94g                                                 
swap rhel -wi-ao----  1.86g   

我創建了一個未加密的掛載點/media，在其中使用以下命令生成了一個密鑰：

dd bs=512 count=4 if=/dev/urandom of=/media/fdekey iflag=fullblock

我用我的密碼添加了密鑰，如下所示：

cryptsetup luksAddKey /dev/mapper/rhel-root /media/fdekey
cryptsetup luksAddKey /dev/mapper/rhel-home /media/fdekey
cryptsetup luksAddKey /dev/mapper/rhel-swap /media/fdekey

然後我編輯/etc/crypttab以添加密鑰：

luks-b7ac522a-52fd-4540-917d-3454dafdf7dc UUID=b7ac522a-52fd-4540-917d-3454dafdf7dc /media/fdekey luks
luks-ad431e02-a49d-4ba3-bf9c-06e7a9f9a7f9 UUID=ad431e02-a49d-4ba3-bf9c-06e7a9f9a7f9 /media/fdekey luks
luks-a3819933-91d5-434b-bb6c-42d273bb34c2 UUID=a3819933-91d5-434b-bb6c-42d273bb34c2 /media/fdekey luks

修改的/etc/dracut.conf

# dracut modules to omit
omit_dracutmodules+="systemd"

# dracut modules to add to the default
add_dracutmodules+="crypt lvm"

修改/etc/default/grub：

rd.luks.key=/media/fdekey:LABEL=media

生成的grub：

grub2-mkconfig -o /boot/grub2/grub.cfg

生成的initramfs：

dracut -fv

輸出df -h：

Filesystem      Size  Used Avail Use% Mounted on
/dev/dm-3        28G  876M   28G   4% /
devtmpfs        9.6G     0  9.6G   0% /dev
tmpfs           9.6G     0  9.6G   0% /dev/shm
tmpfs           9.6G  8.4M  9.6G   1% /run
tmpfs           9.6G     0  9.6G   0% /sys/fs/cgroup
/dev/sda2       4.5G   19M  4.2G   1% /media
/dev/sda1       950M  133M  818M  14% /boot
/dev/dm-5        23G   33M   23G   1% /home
tmpfs           2.0G     0  2.0G   0% /run/user/0

輸出fdisk -l：

Disk /dev/sda: 64.4 GB, 64424509440 bytes, 125829120 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x000a0a6e

  Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048     1953791      975872   83  Linux
/dev/sda2         1953792    11718655     4882432   83  Linux
/dev/sda3        11718656   121114623    54697984   8e  Linux LVM

Disk /dev/mapper/rhel-root: 30.0 GB, 30001856512 bytes, 58597376 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/mapper/rhel-swap: 2000 MB, 2000683008 bytes, 3907584 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/mapper/luks-b7ac522a-52fd-4540-917d-3454dafdf7dc: 1998 MB, 1998585856 bytes, 3903488 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/mapper/luks-a3819933-91d5-434b-bb6c-42d273bb34c2: 30.0 GB, 29999759360 bytes, 58593280 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/mapper/rhel-home: 24.0 GB, 23999807488 bytes, 46874624 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/mapper/luks-ad431e02-a49d-4ba3-bf9c-06e7a9f9a7f9: 24.0 GB, 23997710336 bytes, 46870528 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

我覺得我錯過了一些步驟。啟動後，我仍然被要求輸入密碼。

我需要將我的密鑰文件的路徑添加到dracut.conf並重建 initramfs。

echo 'install_items+="/media/key"' >> /etc/dracut.conf
dracut -fv

看起來您在修改磁碟配置後忘記重新創建 initramfs。要在 RHEL 6/7 中重新創建它，只需以 root 身份執行

dracut --force

引用自：https://unix.stackexchange.com/questions/268160