From dfd09dbcb6f8a562c9cec501efcd333e47e0a86b Mon Sep 17 00:00:00 2001 From: luc Date: Thu, 28 Aug 2025 21:48:03 +0200 Subject: [PATCH] docs/posts/03-security-improvements.md: update Added Void Linux compatibility. --- docs/posts/03-security-improvements.md | 108 +++++++++++++++++++++---- 1 file changed, 94 insertions(+), 14 deletions(-) diff --git a/docs/posts/03-security-improvements.md b/docs/posts/03-security-improvements.md index c4931b2..7efb896 100644 --- a/docs/posts/03-security-improvements.md +++ b/docs/posts/03-security-improvements.md @@ -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 + ``` + 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 -``` \ No newline at end of file +```