lanzaboote/flake.nix

281 lines
9.1 KiB
Nix

{
description = "Lanzaboot Secure Boot Madness";
inputs = {
nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable-small";
nixpkgs-test.url = "github:RaitoBezarius/nixpkgs/simplified-qemu-boot-disks";
crane = {
url = "github:ipetkov/crane";
inputs.nixpkgs.follows = "nixpkgs";
inputs.rust-overlay.follows = "rust-overlay";
inputs.flake-utils.follows = "flake-utils";
};
rust-overlay = {
url = "github:oxalica/rust-overlay";
inputs.nixpkgs.follows = "nixpkgs";
inputs.flake-utils.follows = "flake-utils";
};
flake-utils.url = "github:numtide/flake-utils";
};
outputs = { self, nixpkgs, nixpkgs-test, crane, rust-overlay, ... }:
let
pkgs = import nixpkgs {
system = "x86_64-linux";
overlays = [
rust-overlay.overlays.default
];
};
lib = pkgs.lib;
rust-nightly = pkgs.rust-bin.fromRustupToolchainFile ./rust/lanzaboote/rust-toolchain.toml;
craneLib = crane.lib.x86_64-linux.overrideToolchain rust-nightly;
uefi-run = pkgs.callPackage ./nix/uefi-run.nix {
inherit craneLib;
};
# Build attributes for a Rust application.
buildRustApp = {
src, target ? null, doCheck ? true
}: let
cleanedSrc = craneLib.cleanCargoSource src;
commonArgs = {
src = cleanedSrc;
CARGO_BUILD_TARGET = target;
inherit doCheck;
};
cargoArtifacts = craneLib.buildDepsOnly commonArgs;
in {
package = craneLib.buildPackage (commonArgs // {
inherit cargoArtifacts;
});
clippy = craneLib.cargoClippy (commonArgs // {
inherit cargoArtifacts;
cargoClippyExtraArgs = "-- --deny warnings";
});
};
lanzabooteCrane = buildRustApp {
src = ./rust/lanzaboote;
target = "x86_64-unknown-uefi";
doCheck = false;
};
lanzaboote = lanzabooteCrane.package;
lanzatoolCrane = buildRustApp {
src = ./rust/lanzatool;
};
lanzatool-unwrapped = lanzatoolCrane.package;
lanzatool = pkgs.runCommand "lanzatool" {
nativeBuildInputs = [ pkgs.makeWrapper ];
} ''
mkdir -p $out/bin
# Clean PATH to only contain what we need to do objcopy. Also
# tell lanzatool where to find our UEFI binaries.
makeWrapper ${lanzatool-unwrapped}/bin/lanzatool $out/bin/lanzatool \
--set PATH ${lib.makeBinPath [ pkgs.binutils-unwrapped pkgs.sbsigntool ]} \
--set RUST_BACKTRACE full \
--set LANZABOOTE_STUB ${lanzaboote}/bin/lanzaboote.efi
'';
in {
overlays.default = final: prev: {
inherit lanzatool;
};
nixosModules.lanzaboote = { pkgs, lib, ... }: {
imports = [ ./nix/lanzaboote.nix ];
boot.lanzaboote.package = lib.mkDefault self.packages.${pkgs.system}.lanzatool;
};
packages.x86_64-linux = {
inherit lanzaboote lanzatool;
default = lanzatool;
};
devShells.x86_64-linux.default = pkgs.mkShell {
packages = [
uefi-run
lanzatool
pkgs.openssl
(pkgs.sbctl.override {
databasePath = "pki";
})
pkgs.sbsigntool
pkgs.efitools
pkgs.python39Packages.ovmfvartool
pkgs.qemu
];
inputsFrom = [
lanzaboote
];
};
checks.x86_64-linux = let
mkSecureBootTest = { name, machine ? {}, testScript }: nixpkgs-test.legacyPackages.x86_64-linux.nixosTest {
inherit name testScript;
nodes.machine = { lib, ... }: {
imports = [
self.nixosModules.lanzaboote
machine
];
nixpkgs.overlays = [ self.overlays.default ];
virtualisation = {
useBootLoader = true;
useEFIBoot = true;
useSecureBoot = true;
};
boot.loader.efi = {
canTouchEfiVariables = true;
};
boot.lanzaboote = {
enable = true;
enrollKeys = lib.mkDefault true;
pkiBundle = ./pki;
};
};
};
# Execute a boot test that is intended to fail.
#
mkUnsignedTest = { name, path, appendCrap ? false }: mkSecureBootTest {
inherit name;
testScript = ''
import json
import os.path
bootspec = None
def convert_to_esp(store_file_path):
store_dir = os.path.basename(os.path.dirname(store_file_path))
filename = os.path.basename(store_file_path)
return f'/boot/EFI/nixos/{store_dir}-{filename}.efi'
machine.start()
bootspec = json.loads(machine.succeed("cat /run/current-system/boot.json")).get('v1')
assert bootspec is not None, "Unsupported bootspec version!"
src_path = ${path.src}
dst_path = ${path.dst}
machine.succeed(f"cp -rf {src_path} {dst_path}")
'' + lib.optionalString appendCrap ''
machine.succeed(f"echo Foo >> {dst_path}")
'' +
''
machine.succeed("sync")
machine.crash()
machine.start()
machine.wait_for_console_text("Hash mismatch")
'';
};
in
{
lanzatool-clippy = lanzatoolCrane.clippy;
lanzaboote-clippy = lanzabooteCrane.clippy;
# TODO: user mode: OK
# TODO: how to get in: {deployed, audited} mode ?
lanzaboote-boot = mkSecureBootTest {
name = "signed-files-boot-under-secureboot";
testScript = ''
machine.start()
assert "Secure Boot: enabled (user)" in machine.succeed("bootctl status")
'';
};
lanzaboote-boot-under-sd-stage1 = mkSecureBootTest {
name = "signed-files-boot-under-secureboot-systemd-stage-1";
machine = { ... }: {
boot.initrd.systemd.enable = true;
};
testScript = ''
machine.start()
assert "Secure Boot: enabled (user)" in machine.succeed("bootctl status")
'';
};
# So, this is the responsibility of the lanzatool install
# to run the append-initrd-secret script
# This test assert that lanzatool still do the right thing
# preDeviceCommands should not have any root filesystem mounted
# so it should not be able to find /etc/iamasecret, other than the
# initrd's one.
# which should exist IF lanzatool do the right thing.
lanzaboote-with-initrd-secrets = mkSecureBootTest {
name = "signed-files-boot-with-secrets-under-secureboot";
machine = { ... }: {
boot.initrd.secrets = {
"/etc/iamasecret" = (pkgs.writeText "iamsecret" "this is a very secure secret");
};
boot.initrd.preDeviceCommands = ''
grep "this is a very secure secret" /etc/iamasecret
'';
};
testScript = ''
machine.start()
assert "Secure Boot: enabled (user)" in machine.succeed("bootctl status")
'';
};
# The initrd is not directly signed. Its hash is embedded
# into lanzaboote. To make integrity verification fail, we
# actually have to modify the initrd. Appending crap to the
# end is a harmless way that would make the kernel still
# accept it.
is-initrd-secured = mkUnsignedTest {
name = "unsigned-initrd-do-not-boot-under-secureboot";
path = {
src = "bootspec.get('initrd')";
dst = "convert_to_esp(bootspec.get('initrd'))";
};
appendCrap = true;
};
is-kernel-secured = mkUnsignedTest {
name = "unsigned-kernel-do-not-boot-under-secureboot";
path = {
src = "bootspec.get('kernel')";
dst = "convert_to_esp(bootspec.get('kernel'))";
};
};
specialisation-works = mkSecureBootTest {
name = "specialisation-still-boot-under-secureboot";
machine = { pkgs, ... }: {
specialisation.variant.configuration = {
environment.systemPackages = [
pkgs.efibootmgr
];
};
};
testScript = ''
machine.start()
print(machine.succeed("ls -lah /boot/EFI/Linux"))
print(machine.succeed("cat /run/current-system/boot.json"))
# TODO: make it more reliable to find this filename, i.e. read it from somewhere?
machine.succeed("bootctl set-default nixos-generation-1-specialisation-variant.efi")
machine.succeed("sync")
machine.fail("efibootmgr")
machine.crash()
machine.start()
print(machine.succeed("bootctl"))
# We have efibootmgr in this specialisation.
machine.succeed("efibootmgr")
'';
};
};
};
}