# Hardware Get your gizmos up to speed # Graphics Cards Drivers for hardware accelerated desktop rendering, improving performance and fidelity. The Linux graphics stack consists of several components, but the main component is the `mesa` package. | Manufacturer | OpenGL | Vulkan | Video acceleration | |--------------|------------------|-----------------|--------------------------------------------| | Intel | `mesa` | `vulkan-intel` | `intel-media-driver`, `libva-intel-driver` | | AMD | `mesa` | `vulkan-radeon` | `libva-mesa-driver` | | NVIDIA | `mesa`, `nvidia` | `nvidia-utils` | `libva-mesa-driver`, `nvidia-utils` | ## Intel ~~~bash pacman -S mesa vulkan-intel intel-media-driver libva-intel-driver ~~~ ## AMDGPU ~~~bash pacman -S mesa libva-mesa-driver vulkan-radeon ~~~ ## Nvidia ### Nouveau open source driver ~~~bash pacman -S mesa libva-mesa-driver yay -S nouveau-fw ~~~ ### Proprietary driver ~~~bash pacman -S nvidia nvidia-utils ~~~ #### Early KMS In order to enable early KMS with the prorprietary driver, you will need to take additional steps. The kernel modules of the proprietary kernel module need to be included explicitly in the `MODULES` array of your `/ets/mkinitcpio.conf` file (or a drop-in config file under `/etc/mkinitcpio.conf.d/`): ~~~bash MODULES=(nvidia nvidia_modeset nvidia_uvm nvidia_drm) ~~~ Additionally, remove the `kms` hook from the `HOOKS` array. This is to prevent the unintentional loading of the `nouveau` kernel module. #### Enable Kernel Mode Setting By default, the `nvidia_drm` kernel module does not enable Kernel Mode Setting (KMS). In order for Wayland compositors to function properly, KMS must be explicitly enabled via a kernel command line argument at boot: ~~~ nvidia_drm.modeset=1 ~~~

NOTE: Refer to Boot Loader for how to add the parameter to your boot configuration.

To verify that kernel mode setting is enabled: ~~~bash cat /sys/module/nvidia_drm/parameters/modeset ~~~ `Y` means Kernel Mode Setting was enabled on boot. `N` means Kernel Mode Setting was **not** enabled on boot. # Sound For audio handling on Linux, PipeWire is the currently recommended framework. PipeWire is a server and user space API that provides a platform to handle multimedia pipelines. It is a modern, low-latency audio and video server designed to work with the latest audio use cases and handle professional audio interfaces and applications. PipeWire was created as a replacement for both the PulseAudio sound server and the Jack Audio Connection Kit (JACK) server. It provides a unified interface for handling video and audio streams and is intended to be flexible and extensible, allowing it to address not only audio but other multimedia tasks as well, such as video conferencing, screen capture, and other multimedia applications. It can also work with different hardware devices, including webcams, microphones, and professional audio devices. Additionally, it integrates better with the security models of Flatpak and Wayland. It does so via sandboxing processes from one another, preventing an application from snooping on other applications' audio streams. Before allowing an application to record audio or sharing the screen(e.g. in a browser over WebRTC) it will ask the user for permission to do so. PipeWire implements no connection logic internally, that is the responsibility of a program called a session manager. It watches for new streams and connects them to the appropriate output device or application. There are two session managers to choose from: * **PipeWire Media Session:** A very simple session manager that caters to some basic desktop use cases. It was mostly implemented for testing and as an example for building new session managers. * **WirePlumber:** A more powerful manager and the current recommendation. It is based on a modular design, with Lua plugins that implement the actual management functionality. WirePlumber is the recommended choice, as it is better maintained, receives regular updates and is more feature-rich. ## Installation The most basic PipeWire setup includes the following packages:

NOTE: PipeWire handles Bluetooth audio devices if the pipewire-audio package is installed.

~~~bash pacman -S pipewire pipewire-audio wireplumber ~~~ Additional packages can be installed to extend PipeWire's compatibility and capabilities: | Package | Description | |---------------------|------------------------------------------------------------------------| | `pipewire-alsa` | Support for routing ALSA clients through PipwWire | | `pipewire-jack` | Support for JACK clients | | `pipewire-pulse` | Support for PulseAudio clients (recommended) | | `pipewire-v4l2` | Support for handling video devices, e.g. webcams, tuners, etc. | | `pipewire-zeroconf` | Support for streaming audio over the network, e.g. an AirPlay receiver | ## Streaming audio to an AirPlay receiver PipeWire can send audio to an AirPlay receiver via the `pipewire-zeroconf` package, which includes the necessary RTSP/RAOP modules to create a sink to send audio data to. This requires the Avahi zeroconf daemon. Refer to the [Network](/books/arch-linux/page/network#bkmrk-avahi) section on how to install and setup Avahi. ### Firewall ports If you're using a firewall, make sure that the following ports are open:

TIP: firewalld has a preset for RTSP. Make sure to apply the firewall changes permanently.

| Port | Protocol | Service | |------|----------|-------------------------------------------| | 554 | TCP | RTSP | | 554 | UDP | RTSP | | 6001 | UDP | Some 3rd party AirPlay receivers use this | | 6002 | UDP | Some 3rd party AirPlay receivers use this | ### Auto-load PipeWire RAOP discovery module Create a new drop-in config file, e.g. `~/.config/pipewire/pipewire.conf.d/raop-discover.conf`: ~~~ context.modules = [ { name = libpipewire-module-raop-discover args = { #raop.latency.ms = 1000 stream.rules = [ { matches = [ { raop.ip = "~.*" #raop.ip.version = 4 | 6 #raop.ip.version = 4 #raop.port = 1000 #raop.name = "" #raop.hostname = "" #raop.domain = "" #raop.device = "" #raop.transport = "udp" | "tcp" #raop.encryption.type = "RSA" | "auth_setup" | "none" #raop.audio.codec = "PCM" | "ALAC" | "AAC" | "AAC-ELD" #audio.channels = 2 #audio.format = "S16" | "S24" | "S32" #audio.rate = 44100 #device.model = "" } ] actions = { create-stream = { #raop.password = "" stream.props = { #target.object = "" #media.class = "Audio/Sink" } } } } ] } } ] ~~~ Restart the `pipewire` user unit to make pipewire read the new drop-in config file and load the RAOP module automatically upon login: ~~~bash systemctl restart --user pipewire ~~~ ### Scan for devices on the network You can use the `avahi-browse` utility to scan for devices on your network: ~~~bash avahi-browse --all --ignore-local --terminate ~~~ This will produce a list of devices broadcasting mDNS services over the network (not only AirPlay, but also file sharing, Spotify, Home Kit and various others). You should now be able to `ping` your AirPlay receiver using its `.local` DNS name: ~~~bash ping my-airplay-receiver.local ~~~ If everything worked as intended `wpctl status` should list new sinks to output audio to: ~~~ ... Audio ├─ Devices: │ 53. Starship/Matisse HD Audio Controller [alsa] │ ├─ Sinks: │ 47. My AirPlay Reciever [vol: 1.00] │ * 61. Starship/Matisse HD Audio Controller Analog Stereo [vol: 1.00] ... ~~~ Finally, use your desktop environment's audio settings panel to select your AirPlay receiver as audio output device. # Bluetooth Install the following packages to enable Bluetooth functionality and the necessary tools to control them: ~~~bash pacman -S bluez bluez-utils ~~~ Enable the systemd unit to initialize Bluetooth during boot: ~~~bash systemctl enable bluetooth ~~~ ## Game Controllers Some game controllers (e.g. PlayStation 5 DualSense) require setting `UserspaceHID=true`, which is not the default. To change it, edit the file `/etc/bluetooth/input.conf` and uncomment the line with `UserspaceHID=true` # Printing Install the following packages for printer support: ~~~bash pacman -S cups logrotate system-config-printer ~~~ Enable the following systemd units to initialize the printing system during boot: ~~~bash systemctl enable cups systemctl enable logrotate.timer ~~~ # Trusted Platform Module [Trusted Platform Module](https://en.wikipedia.org/wiki/Trusted_Platform_Module) (TPM) is an international standard for a secure cryptoprocessor, which is a dedicated microprocessor designed to secure hardware by integrating cryptographic keys into devices. In practice a TPM can be used for various different security applications such as [secure boot](https://wiki.sebin-nyshkim.net/books/arch-linux/page/secure-boot), key storage and random number generation. TPM is naturally supported only on devices that have TPM hardware support. If your hardware has TPM support but it is not showing up, it might need to be enabled in the BIOS settings. ## List of Platform Configuration Registers Platform Configuration Registers (PCR) contain hashes that can be read at any time but can only be written via the extend operation, which depends on the previous hash value, thus making a sort of blockchain. They are intended to be used for platform hardware and software integrity checking between boots (e.g. protection against [Evil Maid attack](https://en.wikipedia.org/wiki/en:Evil_Maid_attack)). They can be used to unlock encryption keys and proving that the correct OS was booted. The [TCG PC Client Specific Platform Firmware Profile Specification](https://trustedcomputinggroup.org/resource/pc-client-specific-platform-firmware-profile-specification/) defines the registers in use: | PCR | Use | Notes | |-------|----------------------------------------|-----------------------------------------------------------------------------| | PCR0 | Firmware code | May change if you upgrade your UEFI | | PCR1 | Firmware settings | | | PCR2 | Extended executable code | | | PCR3 | Extended firmware data | Set during Boot Device Select UEFI boot phase | | PCR4 | Boot Manager Code + Boot Attempts | Measures boot manager the devices the firmware tried to boot from | | PCR5 | Boot Manager Configuration + Data | Can measure configuration of boot loaders; includes the GPT Partition Table | | PCR6 | S4/S5 Resume + Power State Events | | | PCR7 | Secure Boot State | Full contents of PK/KEK/db & certificates to validate each boot application | | PCR8 | Hash of kernel cmdline | Supported by grub and systemd-boot | | PCR9 | Hash of initrd | Kernel 6.1 might measure the kernel cmdline | | PCR10 | Reserved for Future Use | | | PCR11 | Hash of Unified kernel image | see [systemd-stub][stub-link] | | PCR12 | Overridden kernel cmdline, Credentials | see [systemd-stub][stub-link] | | PCR13 | System Extensions | see [systemd-stub][stub-link] | | PCR14 | | Unused | | PCR15 | | Unused | | PCR16 | Debug | | | PCR23 | Application Support | The OS can set and reset this PCR. | [stub-link]: https://www.freedesktop.org/software/systemd/man/systemd-stub.html ## Packages | Package | Usage | |-------------------|--------------------------------------------------------------------------------------------| | `tpm2-tss` | Implementation of the TCG Trusted Platform Module 2.0 Software Stack (TSS2) | | `tpm2-tools` | Trusted Platform Module 2.0 tools based on `tpm2-tss` | | `tpm2-abrmd` | **A**ccess **B**roker and **R**esource **M**anagement **D**aemon | | `tpm2-tss-engine` | OpenSSL engine for Trusted Platform Module 2.0 devices | | `tpm2-pkcs11` | PKCS#11 interface for Trusted Platform Module 2.0 hardware | | `tpm2-totp` | Attest the trustworthiness of a device against a human using time-based one-time passwords | ## Configuration 1. Add user to the `tss` group ~~~bash sudo usermod -aG tss $USER ~~~ 1. Enable access broker ~~~bash sudo systemctl enable --now tpm2-abrmd ~~~ 1. Logout and login again ## Usage ### TPM2-based LUKS key You can use the trusted platform module in your computer as a key store to unlock LUKS encrypted volumes with them. Arch Linux comes with `systemd` which itself comes with `systemd-cryptenroll` and allows you to specify a TPM2 device for key storage. Using a TPM for this purpose automates the process of unlocking your LUKS volumes, given that certain conditions are met, e.g. the firmare of the machine and the Secure Boot state.

WARNING: When using this method on your root volume, there are a few caveats to be aware of.

Provided the PCR slots you chose to seal against are considered valid by the system, the TPM will automatically unlock the LUKS volume at boot without the need to enter a password.

However, this also means that in case of theft, the data is no longer protected by the encryption. Furthermore, this also makes you more vulnerable to cold boot attacks, since the computer just has to be booted up to gain access to the decrypted data, without even the need to tamper with the device in order to crack the encryption.

It is therefore strongly recommended to at least pass the --tpm2-with-pin=yes option to systemd-cryptenroll to still have a mechanism for user verification (available with systemd version 251).

#### Enrolling a new key Certain preconditions are necessary to use TPM2 in conjunction with a LUKS encrypted volume: * `tpm2-tss` must be installed * the volume uses LUKS2 encryption (default when using `cryptsetup`) * the initramfs must be `systemd`-based (`mkinitcpio` hooks: `systemd` and `sd-encrypt`) Start by getting a list of TPM2 devices available in your machine:

TIP: If there are no devices listed, make sure the TPM is enabled in your device's firmware. Devices from 2016 onwards usually have a TPM 2.0, as it is a requirement from Microsoft for Windows 10 certification for hardware manufacturers.

~~~bash systemd-cryptenroll --tpm2-device=list ~~~ To enroll a new TPM-based key into a LUKS slot specify the TPM device to generate the key from and the PCRs to seal against, followed by the LUKS volume to save a new slot to (using `/dev/nvme0n1p2` as an example):

ATTENTION: The more PCRs you bind to, the more hardened your setup becomes. But at the same time you can also end up with a less flexible setup — e.g. binding your TPM LUKS key to PCRs 8, 9 and/or 11 harden your system against attempts to boot a kernel image which's hashes aren't measured into these PCRs but the moment your kernel changes (i.e. you update your kernel, change initrd generation, etc.) the PCRs stop validating and trigger a passphrase or recovery key prompt!

TIP: If your device only has one TPM (which is usually the case) you can supply --tpm2-device=auto to use the only device available.

~~~bash systemd-cryptenroll --tpm2-device=/path/to/tpm2_device --tpm2-pcrs=0+7 --tpm2-with-pin=yes /dev/nvme0n1p2 ~~~ It will ask you for a PIN to enter, which you will be asked to put in every time you boot the system. #### Recovery key It is also generally advisable to let `systemd-cryptenroll` generate a recovery key, in case the key stored in the TPM doesn't validate anymore for whatever reason. A recovery key is generated automatically with a character set that's easy to type in while still having high entropy. To generate a recovery key and have it saved to a slot in the LUKS device (using `/dev/nvme0n1p2` as an example): ~~~bash systemd-cryptenroll --recovery-key /dev/nvme0n1p2 ~~~ #### Kernel parameters To actually make systemd use the TPM for unlocking your volume certain kernel parameters have to be set. In your kernel command line, add the following:

TIP: Again, if your device only has one TPM you can supply tpm2-device=auto to use the only device available.

~~~ rd.luks.options=tpm2-device=/path/to/tpm2_device ~~~ ### TOPT code during boot You can use `tpm2-totp` as a means for attestation that the system you are trying to boot is trustworthy by making it display a TOTP code during boot. If the code displayed during boot matches the one in your TOTP app, the system can be considered untampered. Otherwise you have to assume the system is no longer trustworthy and has been tampered with in one way or another.

ATTENTION: If you want to use tpm2-totp in conjunction with Plymouth you will have to use the tpm2-totp-git package from the AUR, since Arch Linux does not officially support Plymouth and the Repo package lacks the initcpio hooks needed for Plymouth support.

Use the plymouth-tpm2-totp hook in conjunction with the encrypt hook, or sd-plymouth-tpm2-totp in conjunction with the sd-encrypt hook.

Generate authentication code and seal against PCRs 0 (hash of UEFI firmware) and 7 (Secure Boot state): ~~~bash sudo tpm2-totp --pcrs=0,7 generate # official package sudo tpm2-totp --pcrs=0,7 init # AUR package ~~~ This will output a QR code on the terminal that you can scan with your TOTP app of choice. Test your TOTP by requesting a 6-digit code to be printed and compare with your TOTP app to verify the codes match: ~~~bash tpm2-totp calculate # official package tpm2-totp show # AUR package ~~~ Add the `tpm2-totp` hook to the HOOKS array in `/etc/mkinitcpio.conf` **before** the `encrypt` hook, else you won't be able to see the TOTP during boot. ### TPM-based SSH keys # Universial 2nd Factor (U2F) Universal 2nd Factor (U2F) is an open standard that strengthens and simplifies two-factor authentication (2FA) using specialized USB or NFC devices based on similar security technology found in smart cards. For support of U2F in major web browsers and system authentication install the following packages: ~~~bash pacman -S libfido2 pam-u2f ~~~ ## Generate U2F key for PAM

NOTE: Generate keys as a regular user!

To start using a U2F key for system-level authentication, keys need to be created first. The default directory these keys will usually be looked for is at `~/.config/Yubico` (since the `pam-u2f` package is developed by Yubico for use with their Yubikeys). Create the directory under your home directory: ~~~bash mkdir ~/.config/Yubico ~~~ The `pam-u2f` package comes with a utility to create keys from the USB device. Create new keys with `pamu2fcfg`:

WARNING: This takes your machine's current host name and assumes it is not re-assigned on network changes! Changing your machine's host name might render the key unable to authenticate you until your machine returns to the original host name.

NOTE: You might be silently prompted to interact with a physical button on your key.

~~~bash pamu2fcfg -o pam://$HOST -i pam://$HOST > ~/.config/Yubico/u2f_keys ~~~ ## System-wide U2F prompts To use your physical security key system-wide and not just for specific use-cases, add the following line **before** the first `auth` line in `/etc/pam.d/system-auth`:

NOTE: Be sure to replace hostname with the actual host name of your machine!

~~~ auth sufficient pam_u2f.so cue origin=pam://hostname appid=pam://hostname ~~~ This will prompt you to touch your physical security key during every attempt at authenticating with your user, whether it's in conjunction with graphical system administrator prompts, `sudo` prompts, display manager login prompts, TTY logins, etc. If the security key is not connected, the system will fall back to regular password prompts. ## Passwordless `sudo`

WARNING: Changes to PAM configuration files apply immediately! Before making any changes to your configuration, start a separate shell with root permissions (e.g. sudo -s). This way you can revert any changes if something goes wrong.

Open `/etc/pam.d/sudo` and add the following as the first line: ~~~ auth sufficient pam_u2f.so cue origin=pam://hostname appid=pam://hostname ~~~ Be sure to replace the `hostname` with the actual host name of your machine. To test, open a new terminal and type `sudo ls`. Your key's LED should flash and after clicking it the command is executed. The option `cue` causes an instruction to appear on what to do, e.g. `Please touch the device`. ## Display manager login ### GDM You can use a U2F key as an actual 2nd factor to your password or as a passwordless login method. #### 2nd factor to password Open `/etc/pam.d/gdm-password` and add the following line **after** the existing `auth` lines:

NOTE: Be sure to replace hostname with the actual host name of your machine!

~~~ auth required pam_u2f.so nouserok cue origin=pam://hostname appid=pam://hostname ~~~ This will require you to have your U2F physical key inserted to authenticate and log you in with your local user account.

WARNING: If you lose your key you will also lose your ability to authenticate and log in to your user account. You could theoretically use sufficient instead of required but this would render the security benefits of this endeavour pointless, as the password would still be enough to gain access to your account.

Please note the use of the `nouserok` option which allows the rule to fail if the user did not configure a key or the key is not connected. The `cue` option will display a prompt to let you know the physical key is waiting for you to touch it. #### Passwordless login Open `/etc/pam.d/gdm-password` and add the following line **before** the existing `auth` lines:

NOTE: Be sure to replace hostname with the actual host name of your machine!

~~~ auth sufficient pam_u2f.so cue origin=pam://hostname appid=pam://hostname ~~~ This will prompt you to touch your physical key in order to log into your local user account. If the key is not present you will be asked for your normal password instead.

ATTENTION: Logging into your local user account like this will prevent auto-unlocking your Login keychain in GNOME's password manager and you will be prompted to provide it after logging in. There is currently no elegant workaround to this other than removing any password on the default keychain to stop the prompts, but this will leave sensitive information inside it unprotected.

## Unlock LUKS container during boot A FIDO2 key can also be used to unlock your LUKS encrypted drives. To register the key, you will need to use the `systemd-cryptenroll` utility and have a [systemd-based initrd](https://wiki.sebin-nyshkim.net/books/arch-linux/page/initramfs). Run the following command to list your detected keys: ~~~bash systemd-cryptenroll --fido2-device=list ~~~ Then you can register the key in a LUKS slot, specifying the path to the FIDO2 device, or using the `auto` value if there is only one device:

ATTENTION: Make sure to pass the device node of your actual LUKS container!

~~~bash systemd-cryptenroll --fido2-device=auto /dev/nvme0n1p2 ~~~ To make systemd use the FIDO2 key for unlocking during boot, add the following option to your `rd.luks.options` list of options: ~~~ rd.luks.options=fido2-device=auto ~~~ When booting your system, watch for the indicator on your FIDO2 hardware key prompting you to touch it.