diff options
author | Tobias Markus <tobias@miglix.eu> | 2023-02-20 01:07:31 +0100 |
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committer | Tobias Markus <tobias@miglix.eu> | 2023-02-20 13:54:49 +0100 |
commit | e83babd4939e26279da58cb9e448848bec5de8f7 (patch) | |
tree | 3da8aba8ee69be6d168baa7d0b092d4322f847cc /nixos/tests/systemd-credentials-tpm2.nix | |
parent | 0621648513a20d6e6a3be974f396c0cebc1cb48d (diff) |
nixos/tests/systemd-credentials-tpm2: Add tests for systemd credentials
Add a test that checks whether systemd can access the TPM in order access credentials requested via Load/SetCredentialEncrypted.
Diffstat (limited to 'nixos/tests/systemd-credentials-tpm2.nix')
-rw-r--r-- | nixos/tests/systemd-credentials-tpm2.nix | 124 |
1 files changed, 124 insertions, 0 deletions
diff --git a/nixos/tests/systemd-credentials-tpm2.nix b/nixos/tests/systemd-credentials-tpm2.nix new file mode 100644 index 0000000000000..d2dc1fd7b615b --- /dev/null +++ b/nixos/tests/systemd-credentials-tpm2.nix @@ -0,0 +1,124 @@ +import ./make-test-python.nix ({ lib, pkgs, system, ... }: + +let + tpmSocketPath = "/tmp/swtpm-sock"; + tpmDeviceModels = { + x86_64-linux = "tpm-tis"; + aarch64-linux = "tpm-tis-device"; + }; +in + +{ + name = "systemd-credentials-tpm2"; + + meta = { + maintainers = with pkgs.lib.maintainers; [ tmarkus ]; + }; + + nodes.machine = { pkgs, ... }: { + virtualisation = { + qemu.options = [ + "-chardev socket,id=chrtpm,path=${tpmSocketPath}" + "-tpmdev emulator,id=tpm_dev_0,chardev=chrtpm" + "-device ${tpmDeviceModels.${system}},tpmdev=tpm_dev_0" + ]; + }; + + boot.initrd.availableKernelModules = [ "tpm_tis" ]; + + environment.systemPackages = with pkgs; [ diffutils ]; + }; + + testScript = '' + import subprocess + from tempfile import TemporaryDirectory + + # From systemd-initrd-luks-tpm2.nix + class Tpm: + def __init__(self): + self.state_dir = TemporaryDirectory() + self.start() + + def start(self): + self.proc = subprocess.Popen(["${pkgs.swtpm}/bin/swtpm", + "socket", + "--tpmstate", f"dir={self.state_dir.name}", + "--ctrl", "type=unixio,path=${tpmSocketPath}", + "--tpm2", + ]) + + # Check whether starting swtpm failed + try: + exit_code = self.proc.wait(timeout=0.2) + if exit_code is not None and exit_code != 0: + raise Exception("failed to start swtpm") + except subprocess.TimeoutExpired: + pass + + """Check whether the swtpm process exited due to an error""" + def check(self): + exit_code = self.proc.poll() + if exit_code is not None and exit_code != 0: + raise Exception("swtpm process died") + + CRED_NAME = "testkey" + CRED_RAW_FILE = f"/root/{CRED_NAME}" + CRED_FILE = f"/root/{CRED_NAME}.cred" + + def systemd_run(machine, cmd): + machine.log(f"Executing command (via systemd-run): \"{cmd}\"") + + (status, out) = machine.execute( " ".join([ + "systemd-run", + "--service-type=exec", + "--quiet", + "--wait", + "-E PATH=\"$PATH\"", + "-p StandardOutput=journal", + "-p StandardError=journal", + f"-p LoadCredentialEncrypted={CRED_NAME}:{CRED_FILE}", + f"$SHELL -c '{cmd}'" + ]) ) + + if status != 0: + raise Exception(f"systemd_run failed (status {status})") + + machine.log("systemd-run finished successfully") + + tpm = Tpm() + + @polling_condition + def swtpm_running(): + tpm.check() + + machine.wait_for_unit("multi-user.target") + + with subtest("Check whether TPM device exists"): + machine.succeed("test -e /dev/tpm0") + machine.succeed("test -e /dev/tpmrm0") + + with subtest("Check whether systemd-creds detects TPM2 correctly"): + cmd = "systemd-creds has-tpm2" + machine.log(f"Running \"{cmd}\"") + (status, _) = machine.execute(cmd) + + # Check exit code equals 0 or 1 (1 means firmware support is missing, which is OK here) + if status != 0 and status != 1: + raise Exception("systemd-creds failed to detect TPM2") + + with subtest("Encrypt credential using systemd-creds"): + machine.succeed(f"dd if=/dev/urandom of={CRED_RAW_FILE} bs=1k count=16") + machine.succeed(f"systemd-creds --with-key=host+tpm2 encrypt --name=testkey {CRED_RAW_FILE} {CRED_FILE}") + + with subtest("Write provided credential and check for equality"): + CRED_OUT_FILE = f"/root/{CRED_NAME}.out" + systemd_run(machine, f"systemd-creds cat testkey > {CRED_OUT_FILE}") + machine.succeed(f"cmp --silent -- {CRED_RAW_FILE} {CRED_OUT_FILE}") + + with subtest("Check whether systemd service can see credential in systemd-creds list"): + systemd_run(machine, f"systemd-creds list | grep {CRED_NAME}") + + with subtest("Check whether systemd service can access credential in $CREDENTIALS_DIRECTORY"): + systemd_run(machine, f"cmp --silent -- $CREDENTIALS_DIRECTORY/{CRED_NAME} {CRED_RAW_FILE}") + ''; +}) |