diff options
Diffstat (limited to 'nixos/tests/systemd-confinement/default.nix')
| -rw-r--r-- | nixos/tests/systemd-confinement/default.nix | 274 |
1 files changed, 274 insertions, 0 deletions
diff --git a/nixos/tests/systemd-confinement/default.nix b/nixos/tests/systemd-confinement/default.nix new file mode 100644 index 0000000000000..15d442d476b08 --- /dev/null +++ b/nixos/tests/systemd-confinement/default.nix @@ -0,0 +1,274 @@ +import ../make-test-python.nix { + name = "systemd-confinement"; + + nodes.machine = { pkgs, lib, ... }: let + testLib = pkgs.python3Packages.buildPythonPackage { + name = "confinement-testlib"; + unpackPhase = '' + cat > setup.py <<EOF + from setuptools import setup + setup(name='confinement-testlib', py_modules=["checkperms"]) + EOF + cp ${./checkperms.py} checkperms.py + ''; + }; + + mkTest = name: testScript: pkgs.writers.writePython3 "${name}.py" { + libraries = [ pkgs.python3Packages.pytest testLib ]; + } '' + # This runs our test script by using pytest's assertion rewriting, so + # that whenever we use "assert <something>", the actual values are + # printed rather than getting a generic AssertionError or the need to + # pass an explicit assertion error message. + import ast + from pathlib import Path + from _pytest.assertion.rewrite import rewrite_asserts + + script = Path('${pkgs.writeText "${name}-main.py" '' + import errno, os, pytest, signal + from subprocess import run + from checkperms import Accessibility, assert_permissions + + ${testScript} + ''}') # noqa + filename = str(script) + source = script.read_bytes() + + tree = ast.parse(source, filename=filename) + rewrite_asserts(tree, source, filename) + exec(compile(tree, filename, 'exec', dont_inherit=True)) + ''; + + mkTestStep = num: { + description, + testScript, + config ? {}, + serviceName ? "test${toString num}", + rawUnit ? null, + }: { + systemd.packages = lib.optional (rawUnit != null) (pkgs.writeTextFile { + name = serviceName; + destination = "/etc/systemd/system/${serviceName}.service"; + text = rawUnit; + }); + + systemd.services.${serviceName} = { + inherit description; + requiredBy = [ "multi-user.target" ]; + confinement = (config.confinement or {}) // { enable = true; }; + serviceConfig = (config.serviceConfig or {}) // { + ExecStart = mkTest serviceName testScript; + Type = "oneshot"; + }; + } // removeAttrs config [ "confinement" "serviceConfig" ]; + }; + + parametrisedTests = lib.concatMap ({ user, privateTmp }: let + withTmp = if privateTmp then "with PrivateTmp" else "without PrivateTmp"; + + serviceConfig = if user == "static-user" then { + User = "chroot-testuser"; + Group = "chroot-testgroup"; + } else if user == "dynamic-user" then { + DynamicUser = true; + } else {}; + + in [ + { description = "${user}, chroot-only confinement ${withTmp}"; + config = { + confinement.mode = "chroot-only"; + # Only set if privateTmp is true to ensure that the default is false. + serviceConfig = serviceConfig // lib.optionalAttrs privateTmp { + PrivateTmp = true; + }; + }; + testScript = if user == "root" then '' + assert os.getuid() == 0 + assert os.getgid() == 0 + + assert_permissions({ + 'bin': Accessibility.READABLE, + 'nix': Accessibility.READABLE, + 'run': Accessibility.READABLE, + ${lib.optionalString privateTmp "'tmp': Accessibility.STICKY,"} + ${lib.optionalString privateTmp "'var': Accessibility.READABLE,"} + ${lib.optionalString privateTmp "'var/tmp': Accessibility.STICKY,"} + }) + '' else '' + assert os.getuid() != 0 + assert os.getgid() != 0 + + assert_permissions({ + 'bin': Accessibility.READABLE, + 'nix': Accessibility.READABLE, + 'run': Accessibility.READABLE, + ${lib.optionalString privateTmp "'tmp': Accessibility.STICKY,"} + ${lib.optionalString privateTmp "'var': Accessibility.READABLE,"} + ${lib.optionalString privateTmp "'var/tmp': Accessibility.STICKY,"} + }) + ''; + } + { description = "${user}, full APIVFS confinement ${withTmp}"; + config = { + # Only set if privateTmp is false to ensure that the default is true. + serviceConfig = serviceConfig // lib.optionalAttrs (!privateTmp) { + PrivateTmp = false; + }; + }; + testScript = if user == "root" then '' + assert os.getuid() == 0 + assert os.getgid() == 0 + + assert_permissions({ + 'bin': Accessibility.READABLE, + 'nix': Accessibility.READABLE, + ${lib.optionalString privateTmp "'tmp': Accessibility.STICKY,"} + 'run': Accessibility.WRITABLE, + + 'proc': Accessibility.SPECIAL, + 'sys': Accessibility.SPECIAL, + 'dev': Accessibility.WRITABLE, + + ${lib.optionalString privateTmp "'var': Accessibility.READABLE,"} + ${lib.optionalString privateTmp "'var/tmp': Accessibility.STICKY,"} + }) + '' else '' + assert os.getuid() != 0 + assert os.getgid() != 0 + + assert_permissions({ + 'bin': Accessibility.READABLE, + 'nix': Accessibility.READABLE, + ${lib.optionalString privateTmp "'tmp': Accessibility.STICKY,"} + 'run': Accessibility.STICKY, + + 'proc': Accessibility.SPECIAL, + 'sys': Accessibility.SPECIAL, + 'dev': Accessibility.SPECIAL, + 'dev/shm': Accessibility.STICKY, + 'dev/mqueue': Accessibility.STICKY, + + ${lib.optionalString privateTmp "'var': Accessibility.READABLE,"} + ${lib.optionalString privateTmp "'var/tmp': Accessibility.STICKY,"} + }) + ''; + } + ]) (lib.cartesianProductOfSets { + user = [ "root" "dynamic-user" "static-user" ]; + privateTmp = [ true false ]; + }); + + in { + imports = lib.imap1 mkTestStep (parametrisedTests ++ [ + { description = "existence of bind-mounted /etc"; + config.serviceConfig.BindReadOnlyPaths = [ "/etc" ]; + testScript = '' + assert Path('/etc/passwd').read_text() + ''; + } + (let + symlink = pkgs.runCommand "symlink" { + target = pkgs.writeText "symlink-target" "got me"; + } "ln -s \"$target\" \"$out\""; + in { + description = "check if symlinks are properly bind-mounted"; + config.confinement.packages = lib.singleton symlink; + testScript = '' + assert Path('${symlink}').read_text() == 'got me' + ''; + }) + { description = "check if StateDirectory works"; + config.serviceConfig.User = "chroot-testuser"; + config.serviceConfig.Group = "chroot-testgroup"; + config.serviceConfig.StateDirectory = "testme"; + + # We restart on purpose here since we want to check whether the state + # directory actually persists. + config.serviceConfig.Restart = "on-failure"; + config.serviceConfig.RestartMode = "direct"; + + testScript = '' + assert not Path('/tmp/canary').exists() + Path('/tmp/canary').touch() + + if (foo := Path('/var/lib/testme/foo')).exists(): + assert Path('/var/lib/testme/foo').read_text() == 'works' + else: + Path('/var/lib/testme/foo').write_text('works') + print('<4>Exiting with failure to check persistence on restart.') + raise SystemExit(1) + ''; + } + { description = "check if /bin/sh works"; + testScript = '' + assert Path('/bin/sh').exists() + + result = run( + ['/bin/sh', '-c', 'echo -n bar'], + capture_output=True, + check=True, + ) + assert result.stdout == b'bar' + ''; + } + { description = "check if suppressing /bin/sh works"; + config.confinement.binSh = null; + testScript = '' + assert not Path('/bin/sh').exists() + with pytest.raises(FileNotFoundError): + run(['/bin/sh', '-c', 'echo foo']) + ''; + } + { description = "check if we can set /bin/sh to something different"; + config.confinement.binSh = "${pkgs.hello}/bin/hello"; + testScript = '' + assert Path('/bin/sh').exists() + result = run( + ['/bin/sh', '-g', 'foo'], + capture_output=True, + check=True, + ) + assert result.stdout == b'foo\n' + ''; + } + { description = "check if only Exec* dependencies are included"; + config.environment.FOOBAR = pkgs.writeText "foobar" "eek"; + testScript = '' + with pytest.raises(FileNotFoundError): + Path(os.environ['FOOBAR']).read_text() + ''; + } + { description = "check if fullUnit includes all dependencies"; + config.environment.FOOBAR = pkgs.writeText "foobar" "eek"; + config.confinement.fullUnit = true; + testScript = '' + assert Path(os.environ['FOOBAR']).read_text() == 'eek' + ''; + } + { description = "check if shipped unit file still works"; + config.confinement.mode = "chroot-only"; + rawUnit = '' + [Service] + SystemCallFilter=~kill + SystemCallErrorNumber=ELOOP + ''; + testScript = '' + with pytest.raises(OSError) as excinfo: + os.kill(os.getpid(), signal.SIGKILL) + assert excinfo.value.errno == errno.ELOOP + ''; + } + ]); + + config.users.groups.chroot-testgroup = {}; + config.users.users.chroot-testuser = { + isSystemUser = true; + description = "Chroot Test User"; + group = "chroot-testgroup"; + }; + }; + + testScript = '' + machine.wait_for_unit("multi-user.target") + ''; +} |