docs/posts/03-security-improvements.md: update

Added Void Linux compatibility.
This commit is contained in:
Luc Bijl 2025-08-28 21:48:03 +02:00
parent b5e73a228d
commit dfd09dbcb6

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@ -9,6 +9,7 @@ authors:
tags:
- Alpine Linux
- Gentoo Linux
- Void Linux
categories:
- Security
---
@ -23,9 +24,24 @@ Linux Security Modules (LSM) is a framework that allows the implementation of va
These security modules may be enabled by adding them to the kernel `cmdline`:
``` shell title="/etc/kernel/cmdline"
... lsm=landlock,lockdown,yama,integrity ...
```
=== "Alpine Linux"
``` shell title="/etc/kernel-hooks.d/secureboot.conf"
cmdline="... lsm=landlock,lockdown,yama,integrity ..."
```
=== "Gentoo Linux"
``` shell title="/etc/kernel/cmdline"
... lsm=landlock,lockdown,yama,integrity ...
```
=== "Void Linux"
``` shell title="/etc/dracut.conf.d/cmdline.conf"
kernel_cmdline="... lsm=landlock,lockdown,yama,integrity ..."
```
### Landlock
@ -69,23 +85,55 @@ AppArmor is a security module that provides a simpler alternative to SELinux. It
sh# apk add apparmor apparmor-utils apparmor-profiles
```
and add it to the boot runlevel:
``` shell-session
sh# rc-update add apparmor boot
```
=== "Gentoo Linux"
``` shell-session
sh# emerge -a apparmor apparmor-utils apparmor-profiles
```
and add it to the boot runlevel:
and add it to the boot runlevel:
``` shell-session
sh# rc-update add apparmor boot
```
``` shell-session
sh# rc-update add apparmor boot
```
=== "Void Linux"
``` shell-session
sh# xbps-install apparmor apparmor-utils apparmor-profiles
```
and add the service:
``` shell-session
sh# ln -s /etc/sv/apparmor /var/service
```
Add `apparmor` to the kernel `cmdline` to make it operational:
``` shell title="/etc/kernel/cmdline"
... lsm=...,apparmor apparmor=1 ...
```
=== "Alpine Linux"
``` shell title="/etc/kernel-hooks.d/secureboot.conf"
cmdline="... lsm=...,apparmor apparmor=1 ..."
```
=== "Gentoo Linux"
``` shell title="/etc/kernel/cmdline"
... lsm=...,apparmor apparmor=1 ...
```
=== "Void Linux"
``` shell title="/etc/dracut.conf.d/cmdline.conf"
kernel_cmdline="... lsm=...,apparmor apparmor=1 ..."
```
Then reconfigure the `kernel`:
@ -101,6 +149,12 @@ Then reconfigure the `kernel`:
sh# emerge --config gentoo-kernel
```
=== "Void Linux"
``` shell-session
sh# xbps-reconfigure -f linux<version>
```
You can check the status of `apparmor` with `apparmor-utils`:
``` shell-session
@ -111,9 +165,23 @@ sh# aa-status
Boot parameters configure the bootloader to parse the relevant settings to the kernel at boot. Hardening the boot process will improve the overall security of the system. The listed boot parameters in this chapter can be parsed into the kernel `cmdline`:
``` shell title="/etc/kernel/cmdline"
... slab_nomerge init_on_alloc=1 init_on_free=1 page_alloc.shuffle=1 pti=on ...
```
=== "Alpine Linux"
``` shell title="/etc/kernel-hooks.d/secureboot.conf"
cmdline="... slab_nomerge init_on_alloc=1 init_on_free=1 page_alloc.shuffle=1 pti=on ..."
```
=== "Gentoo Linux"
``` shell title="/etc/kernel/cmdline"
... slab_nomerge init_on_alloc=1 init_on_free=1 page_alloc.shuffle=1 pti=on ...
```
=== "Void Linux"
``` shell title="/etc/dracut.conf.d/cmdline.conf"
kernel_cmdline="... slab_nomerge init_on_alloc=1 init_on_free=1 page_alloc.shuffle=1 pti=on ..."
```
### Mitigations of system vulnerabilities
@ -275,6 +343,12 @@ The default memory allocator of `musl` is already reasonably secure but not as s
sh# emerge -a hardened-malloc
```
=== "Void Linux"
``` shell-session
sh# xbps-install hardened-malloc
```
and set it to system-wide edit:
``` shell title="/etc/ld-musl-x86_64.path"
@ -308,8 +382,14 @@ Improve the security of the system by increasing the entropy with the `jitterent
sh# emerge -a jitterentropy
```
=== "Void Linux"
``` shell-session
sh# xbps-install jitterentropy
```
and make sure that the module gets loaded:
``` shell title="/etc/modules-load.d/entropy.conf"
jitterentropy_rng
```
```