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import ./make-test-python.nix ({ pkgs, ... } : {
name = "hardened";
meta = with pkgs.lib.maintainers; {
maintainers = [ joachifm ];
};
machine =
{ lib, pkgs, config, ... }:
with lib;
{ users.users.alice = { isNormalUser = true; extraGroups = [ "proc" ]; };
users.users.sybil = { isNormalUser = true; group = "wheel"; };
imports = [ ../modules/profiles/hardened.nix ];
environment.memoryAllocator.provider = "graphene-hardened";
nix.settings.sandbox = false;
virtualisation.emptyDiskImages = [ 4096 ];
boot.initrd.postDeviceCommands = ''
${pkgs.dosfstools}/bin/mkfs.vfat -n EFISYS /dev/vdb
'';
virtualisation.fileSystems = {
"/efi" = {
device = "/dev/disk/by-label/EFISYS";
fsType = "vfat";
options = [ "noauto" ];
};
};
boot.extraModulePackages =
optional (versionOlder config.boot.kernelPackages.kernel.version "5.6")
config.boot.kernelPackages.wireguard;
boot.kernelModules = [ "wireguard" ];
};
testScript =
let
hardened-malloc-tests = pkgs.graphene-hardened-malloc.ld-preload-tests;
in
''
machine.wait_for_unit("multi-user.target")
with subtest("AppArmor profiles are loaded"):
machine.succeed("systemctl status apparmor.service")
# AppArmor securityfs
with subtest("AppArmor securityfs is mounted"):
machine.succeed("mountpoint -q /sys/kernel/security")
machine.succeed("cat /sys/kernel/security/apparmor/profiles")
# Test loading out-of-tree modules
with subtest("Out-of-tree modules can be loaded"):
machine.succeed("grep -Fq wireguard /proc/modules")
# Test kernel module hardening
with subtest("No more kernel modules can be loaded"):
# note: this better a be module we normally wouldn't load ...
machine.wait_for_unit("disable-kernel-module-loading.service")
machine.fail("modprobe dccp")
# Test userns
with subtest("User namespaces are restricted"):
machine.succeed("unshare --user true")
machine.fail("su -l alice -c 'unshare --user true'")
# Test dmesg restriction
with subtest("Regular users cannot access dmesg"):
machine.fail("su -l alice -c dmesg")
# Test access to kcore
with subtest("Kcore is inaccessible as root"):
machine.fail("cat /proc/kcore")
# Test deferred mount
with subtest("Deferred mounts work"):
machine.fail("mountpoint -q /efi") # was deferred
machine.execute("mkdir -p /efi")
machine.succeed("mount /dev/disk/by-label/EFISYS /efi")
machine.succeed("mountpoint -q /efi") # now mounted
# Test Nix dæmon usage
with subtest("nix-daemon cannot be used by all users"):
machine.fail("su -l nobody -s /bin/sh -c 'nix ping-store'")
machine.succeed("su -l alice -c 'nix ping-store'")
# Test kernel image protection
with subtest("The kernel image is protected"):
machine.fail("systemctl hibernate")
machine.fail("systemctl kexec")
with subtest("The hardened memory allocator works"):
machine.succeed("${hardened-malloc-tests}/bin/run-tests")
'';
})
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