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content/posts/linux/Desktop-Linux-Hardening.md
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@ -21,6 +21,64 @@ Most Linux distributions have an option within its installer for enabling LUKS f
By default, `cryptsetup` does not setup authenticated encryption. If you are configuring partitioning using the command line, you can enable integrity with the `--integrity` argument. By default, `cryptsetup` does not setup authenticated encryption. If you are configuring partitioning using the command line, you can enable integrity with the `--integrity` argument.
### TPM enrollment
If you have a [TPM](https://en.wikipedia.org/wiki/Trusted_Platform_Module) chip in your computer, you can use it in addition with LUKS.
A full guide how to install is available in this [gist](https://gist.github.com/jdoss/777e8b52c8d88eb87467935769c98a95) or in [Arch's documentation](https://wiki.archlinux.org/title/Trusted_Platform_Module#Data-at-rest_encryption_with_LUKS).
Check if you have TPM available :
```
# systemd-cryptenroll --tpm2-device=list
```
You must have Secure Boot enabled, to check so :
```
# mokutil --sb-state
```
If it's set to "Disabled", you need to enable it in the UEFI firmware.
Check your encrypted volumes :
```
# blkid -t TYPE=crypto_LUKS
```
Then, you can finally enroll your encrypted volumes :
```
# systemd-cryptenroll --tpm2-device=auto --tpm2-pcrs=0+2+4+7 /dev/sdX --tpm2-with-pin=yes
```
Replace sdX with the right volume.
It will ask you the passphrase (you have previously chosen with LUKS) then it will prompt you a PIN for TPM.
The PIN should be **different** from the LUKS passphrase.
If you have several volumes, you can redo the command with the right volume, etc.
Finally, edit `/etc/crypttab` and add at the end of each line `tpm2-device=auto,discard`, like so :
`luks-014aa5a6-a007-11ec-a054-7c10c93c41b1 UUID=0818cd36-a007-11ec-aaab-7c10c93c41b1 - tpm2-device=auto,discard`
Then, edit `/etc/default/grub` and add `rd.luks.options=tpm2-device=auto` in `GRUB_CMDLINE_LINUX`
You can optionally generate a recovery key :
```
# systemd-cryptenroll --recovery-key /dev/sdX
```
Check and reboot :
```
# systemd-cryptenroll /dev/sdX
SLOT TYPE
0 password
1 tpm2
2 recovery
```
When booting, it will ask you the password for LUKS, then the TPM2 PIN.
Note that with secure boot enabled, you should manually sign your NVidia drivers with [akmod](https://github.com/larsks/akmod-sign-modules).
### Encrypted Swap ### Encrypted Swap
Consider using [encrypted swap](https://wiki.archlinux.org/title/Dm-crypt/Swap_encryption) or [ZRAM](https://wiki.archlinux.org/title/Swap#zram-generator) instead of unencrypted swap to avoid potential security issues with sensitive data being pushed to [swap space](https://en.wikipedia.org/wiki/Memory_paging). While ZRAM can be set up post-installation, if you want to use encrypted swap, you should set it up while partitioning your drive. Consider using [encrypted swap](https://wiki.archlinux.org/title/Dm-crypt/Swap_encryption) or [ZRAM](https://wiki.archlinux.org/title/Swap#zram-generator) instead of unencrypted swap to avoid potential security issues with sensitive data being pushed to [swap space](https://en.wikipedia.org/wiki/Memory_paging). While ZRAM can be set up post-installation, if you want to use encrypted swap, you should set it up while partitioning your drive.