Hi, I’m in a process of making fast, (extrenely) secure, and modern laptop. Currently I have Arch Linux with encrypted root partition (unlocked with Nitrokey or long password), secure boot, linux-hardened, firewalld, etc.

I’m running linux-hardened with custom config. I enabled AMD SME, kernel lockdown, added some xanmod patch for more specific cpus, and disabled some unnedded drivers (only those that I’m 100% sure I don’t need - Intel, NVidia, Microsoft, Google, Amazon, Virtio). Currently it takes ~50 minutes to recompile the kernel. Are there any tutorials what drivers to disable to speed up this process? After doing that I will try to compile it with -O3 and LTO. Do you know any patches for performance?

I’m planning to enable encrypted swap, install ClaimAV and install flatpak versions for every non open-source app I have.

I also want to have SELinux. Does anyone know where can I learn it? I had it on Fedora and it was not fun using it.

What are other ways I can make my laptop more secure?

  • ourob@discuss.tchncs.deEnglish
    242·
    10 months ago

    Look into installing AppArmor instead of SELinux. AppArmor is easier to configure, and SELinux is not officially supported on Arch.

    • GravitySpoiled@lemmy.mlEnglish
      6·
      10 months ago

      Running SELinux under a Linux distribution requires three things: An SELinux enabled kernel, SELinux Userspace tools and libraries, and SELinux Policies (mostly based on the Reference Policy). Some common Linux programs will also need to be patched/compiled with SELinux features.

      Now I know why I didn’t bother with selinux back when I used arch. I never had any issues with it on fedora with zero maintenance.

  • vatson112@lemm.ee
    6·
    10 months ago

    There are also some kernel settings that you may find useful. Currently I am on the mobile and cannot remember the names. Text me if you need help

    Network:

    Enable rp and arp filter

    Disable IP forwarding if you don’t use docker

    Disable tcp timestamp

    Disable icmp broadcast

    Enable syncookies

    Enable source route checking

    Other:

    Enable hard and soft link protection (it is may broke your system, use carefully)

    Enable kptr restrict

    Disable kexec

    Disable sysrq

    Enable randomize virtual memory address

    Disable JIT for ebpf programms

    Disable loading drivers via modprobe in live kernel.

    Also check which hardware mitigations is disabled in your kernel. (Spectre, meltdawn) You may enable KASL

    Also use selinux or apparmor. I prefer Selinux.

    Enable auditd and configure it for auditing actions that your find useful.

    • chevy9294OPEnglish
      2·
      10 months ago

      Thank you for the list! Do you maybe know where can I find explanations what does each option do? I know only half of them and I already use some of them.

      • vatson112@lemm.ee
        3·
        10 months ago

        I will describe settings that are not so easy to google and a few new thoughts.

        kptr restrict:

        https://wiki.archlinux.org/title/security

        https://lwn.net/Articles/420403/

        Kexec:

        You may google about mechanics, but basically, it is just a mechanism to ‘reexec’ your kernel to something different, usually another kernel, but you can boot netboot.xyz, for example.

        But now imagine that it will boot a kernel that will dump the output of all your traffic, or will dump all your keyboard keypresses (keylogger).

        These are unlikely scenarios. But I prefer to disable this feature since I don’t use it anyway.

        Also, about keyloggers. Any program inside your X session may grab all your keyboard events. Literally last week I wrote a keylogger in rust in 70 lines of code. Therefore, use Wayland.

        Ebpf JIT:

        There I misleaded you.

        There is some new information about JIT and security. See https://youtu.be/kvt4wdXEuRU?si=3imn8PAEbvgjWTU3

        According to the update, you need to set bpf_jit_harden=2 and unprivileged_bpf_disabled=1. (Even unprivileged ebpf may crash your kernel. For some unknown reason, this is not recognized as a problem.)

        Randomize virtual memory address:

        https://www.techtarget.com/searchsecurity/definition/address-space-layout-randomization-ASLR#:~:text=Address space layout randomization (ASLR) is a memory-protection,executables are loaded into memory.

        systemd

        If you use systemd your can use systemd-analyze tool to harden your units settings.

        Also, I remember the tool you can use.

        There are some security certifications - most used are pcidss or stig. There are guidelines to improve security.

        You can use openscap with a profile (pcidss or stig or both) and it will check if your system satisfies these guidelines.

        This may give you some thoughts.

        • chevy9294OPEnglish
          1·
          10 months ago

          Thank you very much for this detailed explanation! Looks like kptr and kexec are already disabled and enabled randomized virtual memory address in the hardened kernel. I will check for ebpf. Security certs seem interesting, I will defenetly look into them.

  • Pantherina@feddit.de
    5·
    10 months ago

    Look at secureblue for more things

    • hardened malloc (preloading is somewhat complex for flatpaks)
    • maybe more kargs

    That custom kernel sounds very cool. Not sure if replacing it works on Fedora Atomic, would be very much needed

    SELinux confined users is also very important, SELinux is kinda contradictory to flatpak though, as they do the same things often and Flatpaks often dont work because they are not built for it.

    • chevy9294OPEnglish
      2·
      10 months ago

      I will try hardened_malloc, I already use it on my phone. I have GrapheneOS.

      • Pantherina@feddit.de
        2·
        10 months ago

        Same. It works really well, I am doing some kind of project building a hardened Firefox. It has hardened build parameters, removed jemalloc (so it uses hardened_malloc, otherwise it fails to start with memory issues), and I also experiment with various optimization flags as I have a x86_64-v4 intel CPU.

        This repo is also interesting.

        Secureblue has Chromium preinstalled with a hardening and also privacy policy, but I used googerteller and damn that thing pings Google every second, its scary.

        • chevy9294OPEnglish
          1·
          10 months ago

          Now I’ve installed it and Librewolf works nornally. Is that normal or is malloc not working or is Librewolf compiled with hardened malloc?

          I’ve heard about googerteller and I never thought someone will use it (except to try it)

          • Pantherina@feddit.de
            3·
            10 months ago

            Librewolf uses jemalloc and I have no idea but Flatpak browsers are not broken.

            I also asked Fedora people and Fedora Firefox also allows replacing the malloc, but as the package is already removed from the image you cant normally install it back.

            Yup, googerteller is damn scary. Chromium contacts Google when opening the profile picker, loading the addons, listing saved passwords

  • bodaciousFern@lemmy.dbzer0.com
    2·
    10 months ago

    50 minutes seems way too long - I run Gentoo on a 2nd gen i5 and my kernel compile is always under 20 minutes.

    You are using make -j4 or make -j(number of CPU cores) for parallel compile, right?

    • chevy9294OPEnglish
      2·
      10 months ago

      On laptop with Ryzen 5 5500U (12 threads) it takes 50 minutes and on desktop with Ryzen 7 3700X (16 threads) it takes 20 minutes. I use all threads to compile the kernel.

      It compiles way waster with Gentoo, because it has minimal config. I used the default config from Arch repos and modified it. It’s full of unneeded drivers, but I’m scared of disabling them. I already disabled wrong drivers a few times and had to use different kernel to boot.

  • Atemu@lemmy.ml
    1·
    10 months ago

    Currently it takes ~50 minutes to recompile the kernel. Are there any tutorials what drivers to disable to speed up this process?

    Step 1: Buy a faster CPU.

    The only thing you could do is ccache but that’s just a cache and can get invalidated whenever.

    After doing that I will try to compile it with -O3 and LTO.

    Don’t use -O3, especially when your goal is to harden. It has no measurable benefit beyond measurement bias due to memory layout changes and some of its optimisations may produce wrong code which is a big no-no if your goal is to harden.

    install ClaimAV

    Are you planning to host a file share for Windows system or what are you trying to achieve using ClamAV?

    install flatpak versions for every non open-source app

    You’re going to such lengths and even consider snake oil in order to “harden” your system and then you’re telling me you want to run proprietary (often known malicious) software on it?

    What are you trying to achieve here? What do you want to protect against whom? Create a proper threat model before you wildly apply “hardening” that is likely ineffective at protecting against the threats that actually matter to you.

    I also want to have SELinux.

    Good luck with that. Distros with proper SELinux setups (i.e. Android, Redhat) employ teams of people to write SELinux rules for them.

    I won’t discourage you from learning SELinux but know that setting up SELinux for your entire system when the distro does not support it already is not something you can realistically achieve on your own.

  • scratchandgame@lemmy.mlTiếng Việt
    11·
    10 months ago

    (arch still use systemd)

    and linux still not have base system software sandboxed (you can’t enforce)

    Currently it takes ~50 minutes to recompile the kernel

    try make with -j