2 files changed, 578 insertions, 0 deletions

diff --git a/tools/ca/ca/__main__.py b/tools/ca/ca/__main__.py
new file mode 100644
index 00000000..e3e4bbe6
--- /dev/null
+++ b/tools/ca/ca/__main__.py
@@ -0,0 +1,568 @@
+import sys, os
+
+import logging
+import argparse
+
+from inspect import signature
+
+from enum import Enum, auto
+from contextlib import contextmanager
+
+from cryptography import __version__ as cryptography_version
+from cryptography.hazmat.backends import openssl
+from cryptography import x509
+from cryptography.x509.oid import NameOID, ExtendedKeyUsageOID, ExtensionOID
+from cryptography.hazmat.primitives import serialization, hashes
+from cryptography.hazmat.primitives.serialization import PrivateFormat, pkcs12
+from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PrivateKey
+from cryptography.hazmat.primitives.asymmetric.ed448 import Ed448PrivateKey
+from cryptography.hazmat.primitives.asymmetric.rsa import RSAPrivateKey
+from cryptography.hazmat.primitives.asymmetric import rsa
+from pathlib import Path
+from atomicwrites import atomic_write
+from fqdn import FQDN
+from datetime import datetime, timedelta, timezone
+from math import ceil, ldexp
+import re
+from getpass import getpass
+from itertools import count
+from tempfile import TemporaryFile
+import subprocess
+import json
+from leapseconddata import LeapSecondData
+
+
+class KeyType(Enum):
+    ED448 = 'ed448'
+    ED25519 = 'ed25519'
+    RSA4096 = 'rsa4096'
+    RSA2048 = 'rsa2048'
+
+    def generate(self):
+        match self:
+            case KeyType.ED448:
+                return Ed448PrivateKey.generate()
+            case KeyType.ED25519:
+                return Ed25519PrivateKey.generate()
+            case KeyType.RSA4096:
+                return rsa.generate_private_key(
+                    public_exponent = 65537,
+                    key_size = 4096,
+                )
+            case KeyType.RSA2048:
+                return rsa.generate_private_key(
+                    public_exponent = 65537,
+                    key_size = 2048,
+                )
+
+    def aligned(self, key):
+        match self:
+            case KeyType.ED448:
+                return isinstance(key, Ed448PrivateKey)
+            case KeyType.ED25519:
+                return isinstance(key, Ed25519PrivateKey)
+            case KeyType.RSA4096:
+                return isinstance(key, RSAPrivateKey) and key.key_size == 4096
+            case KeyType.RSA2048:
+                return isinstance(key, RSAPrivateKey) and key.key_size == 2048
+
+    def __str__(self):
+        return self.value
+
+    @classmethod
+    def from_string(cls, s):
+        try:
+            return cls(s)
+        except KeyError:
+            raise ValueError()
+
+class ValidFQDN(FQDN):
+    def __init__(self, *args, **kwds):
+        super().__init__(*args, **kwds)
+
+        if not self.is_valid:
+            raise ValueError(f'‘{self}’ is not valid')
+
+def duration(inp_str):
+    delta = timedelta()
+
+    item_re = re.compile(r'\W*(?P<value>\d+)\W*(?P<unit>(?i:d|h|m(?!s)|s|ms|µs))')
+
+    match = item_re.match(inp_str)
+    while match:
+        val = int(match.group('value'))
+        unit = match.group('unit').lower()
+
+        if unit == 'd':
+            delta += timedelta(days=val)
+        elif unit == 'h':
+            delta += timedelta(hours=val)
+        elif unit == 'm':
+            delta += timedelta(minutes=val)
+        elif unit == 's':
+            delta += timedelta(seconds=val)
+        elif unit == 'ms':
+            delta += timedelta(milliseconds=val)
+        elif unit == 'µs' or unit == 'us':
+            delta += timedelta(microseconds=val)
+        else:
+            raise ValueError(f'Unknown time unit ‘{unit:s}’')
+
+        inp_str = inp_str[match.end():]
+        match = item_re.match(inp_str)
+    else:
+        if re.match('\w', inp_str):
+            raise ValueError(f'Parsing of duration resulted in leftovers: ‘{inp_str:s}’')
+
+    return delta
+
+@contextmanager
+def umask(desired_umask):
+    """ A little helper to safely set and restore umask(2). """
+    try:
+        prev_umask = os.umask(0)
+        os.umask(prev_umask | desired_umask)
+        yield
+    finally:
+        os.umask(prev_umask)
+
+class BooleanAction(argparse.Action):
+    def __init__(self, option_strings, dest, nargs=None, **kwargs):
+        super(BooleanAction, self).__init__(option_strings, dest, nargs=0, **kwargs)
+
+    def __call__(self, parser, namespace, values, option_string=None):
+        setattr(namespace, self.dest, False if option_string.startswith('--no') else True)
+
+
+def load_key(keyfile, prompt='CA private key password: '):
+    key = None
+    with open(keyfile, 'rb') as f:
+        is_sops = False
+        try:
+            sops_json = json.load(f)
+            is_sops = 'sops' in sops_json
+        except json.JSONDecodeError:
+            pass
+
+        f.seek(0)
+
+        if not is_sops:
+            try:
+                key = serialization.load_pem_private_key(f.read(), password=None)
+            except TypeError:
+                pw = getpass(prompt=prompt)
+                key = serialization.load_pem_private_key(f.read(), password=bytes(pw, sys.stdin.encoding))
+        else:
+            cmd = ['sops', '-d', f'/dev/fd/{f.fileno()}']
+            with subprocess.Popen(cmd, stdout=subprocess.PIPE, pass_fds=(f.fileno(),)) as proc:
+                key = serialization.load_pem_private_key(proc.stdout.read(), password=None)
+                ret = proc.wait()
+                if ret != 0:
+                    raise subprocess.CalledProcessErrror(ret, cmd)
+
+    return key
+
+def mv_bak(path):
+    global logger
+
+    bak_path = path.parent / f'{path.name}.bak'
+    for n in count(2):
+        if not bak_path.exists():
+            break
+        bak_path = path.parent / f'{path.name}.bak{n}'
+
+    logger.warn('Renaming ‘%s’ to ‘%s’...', path, bak_path)
+    path.rename(bak_path)
+
+def tai64nint(dt):
+    global leapsecond_data
+
+    have_data = False
+    try:
+        have_data = bool(leapsecond_data)
+    except NameError:
+        pass
+
+    if not have_data:
+        leapsecond_data = LeapSecondData.from_file(Path(os.getenv('LEAPSECONDS_FILE')))
+
+    tai_dt = leapsecond_data.to_tai(dt)
+    seconds = int(tai_dt.timestamp())
+    nanoseconds = int((tai_dt.timestamp() - seconds) / 1e-9)
+    seconds += int(ldexp(1, 62))
+    return seconds << 32 | nanoseconds
+
+def write_genkey(key_type, sops, keyfile):
+    if keyfile.exists():
+        raise ValueError(f'Keyfile exists: {keyfile}')
+
+    key = None
+
+    def genkey(fh):
+        nonlocal key, key_type
+
+        logger.debug('Generating new privkey...')
+        key = key_type.generate()
+        priv_bytes = key.private_bytes(encoding=serialization.Encoding.PEM, format=serialization.PrivateFormat.PKCS8, encryption_algorithm=serialization.NoEncryption())
+        fh.write(priv_bytes)
+
+    if not sops:
+        with umask(0o0177), atomic_write(keyfile, overwrite=False, mode='wb') as fh:
+            logger.info('Writing new privkey to ‘%s’...', keyfile)
+            genkey(fh)
+        logger.debug('Adjusting permissions for ‘%s’...', keyfile)
+        os.chmod(keyfile, 0o0400)
+    else:
+        with TemporaryFile(mode='wb') as tf:
+            genkey(tf)
+            tf.seek(0)
+
+            with umask(0o0177), atomic_write(keyfile, overwrite=False, mode='wb') as fh:
+                logger.info('Encrypting new privkey to ‘%s’...', keyfile)
+                subprocess.run(['sops', '-e', f'/dev/fd/{tf.fileno()}'], stdout=fh, pass_fds=(tf.fileno(),), check=True)
+            logger.debug('Adjusting permissions for ‘%s’...', keyfile)
+            os.chmod(keyfile, 0o0400)
+
+    return key
+
+def initca(ca_cert, ca_key, key_type, subject, clock_skew, validity, sops):
+    global logger
+
+    key = None
+    try:
+        key = load_key(ca_key)
+        logger.info('Successfully loaded privkey from ‘%s’', ca_key)
+
+        if not key_type.aligned(key):
+            logger.warn('Private key ‘%s’ does not align with requested type %s', ca_key, key_type)
+
+            try:
+                mv_bak(ca_key)
+            except FileNotFoundError:
+                pass
+            try:
+                mv_bak(ca_cert)
+            except FileNotFoundError:
+                pass
+
+            raise FileNotFoundError(f'Key does not align with requested type: {ca_key}')
+    except FileNotFoundError:
+        key = write_genkey(key_type, sops, ca_key)
+
+    cert = None
+    try:
+        with open(ca_cert, 'rb') as fh:
+            cert = x509.load_pem_x509_certificate(fh.read())
+            logger.info('Successfully loaded certificate from ‘%s’', ca_cert)
+    except FileNotFoundError:
+        logger.debug('Generating new certificate...')
+
+        now = datetime.utcnow()
+        name = x509.Name([
+            x509.NameAttribute(NameOID.COMMON_NAME, subject.relative)
+        ])
+
+        cert = x509.CertificateBuilder().subject_name(
+            name
+        ).public_key(
+            key.public_key()
+        ).serial_number(
+            x509.random_serial_number()
+        ).not_valid_before(
+            now - clock_skew
+        ).not_valid_after(
+            now + validity
+        ).issuer_name(
+            name
+        ).add_extension(
+            x509.AuthorityKeyIdentifier.from_issuer_public_key(key.public_key()),
+            False
+        ).add_extension(
+            x509.SubjectKeyIdentifier.from_public_key(key.public_key()),
+            False
+        ).add_extension(
+            x509.KeyUsage(digital_signature=True, content_commitment=False, key_encipherment=False, data_encipherment=False, key_agreement=False, key_cert_sign=True, crl_sign=True, encipher_only=False, decipher_only=False),
+            True
+        ).add_extension(
+            x509.BasicConstraints(ca=True, path_length=None),
+            True
+        ).sign(key, None if isinstance(key, Ed25519PrivateKey) or isinstance(key, Ed448PrivateKey) else hashes.SHA512())
+
+        with umask(0o0133), atomic_write(ca_cert, overwrite=False, mode='wb') as cf:
+            logger.info('Writing new certificate to ‘%s’...', ca_cert)
+            cf.write(cert.public_bytes(serialization.Encoding.PEM))
+        logger.debug('Adjusting permissions for ‘%s’...', ca_cert)
+        os.chmod(ca_cert, 0o0444)
+
+def signcsr(ca_cert, ca_key, clock_skew, validity, subject, alternative_name, ignore_alternative_names, csr, output):
+    csr_bytes = None
+    try:
+        csr_bytes = csr.read()
+    except AttributeError:
+        csr_bytes = csr
+
+    csr = x509.load_pem_x509_csr(csr_bytes)
+    if not subject:
+        common_name_attrs = csr.subject.get_attributes_for_oid(NameOID.COMMON_NAME)
+        if len(common_name_attrs) != 1:
+            raise InvalidParamsError('Invalid name structure in CSR')
+        subject = common_name_attrs[0].value.lower()
+        logger.warn('Using subject common name from csr: %s', subject)
+    name = x509.Name([
+        x509.NameAttribute(NameOID.COMMON_NAME, subject)
+    ])
+
+    if not ignore_alternative_names:
+        ext = csr.extensions.get_extension_for_oid(ExtensionOID.SUBJECT_ALTERNATIVE_NAME)
+        csr_alt_names = ext.value.get_values_for_type(x509.DNSName)
+        logger.warn('Using alternative names from csr: %s', csr_alt_names)
+        alternative_name = list(set(alternative_name) | set(csr_alt_names))
+
+    ca_key = load_key(ca_key)
+    with open(ca_cert, 'rb') as fh:
+        ca_cert = x509.load_pem_x509_certificate(fh.read())
+
+    now = datetime.now(tz=timezone.utc)
+    cert = x509.CertificateBuilder().subject_name(
+        name
+    ).public_key(
+        csr.public_key()
+    ).serial_number(
+        (tai64nint(now) << 24) | (x509.random_serial_number() & int(ldexp(1, 24) - 1))
+    ).not_valid_before(
+        now - clock_skew
+    ).not_valid_after(
+        now + validity
+    ).issuer_name(
+        ca_cert.subject
+    ).add_extension(
+        x509.AuthorityKeyIdentifier.from_issuer_public_key(ca_cert.public_key()),
+        False
+    ).add_extension(
+        x509.SubjectKeyIdentifier.from_public_key(csr.public_key()),
+        False
+    ).add_extension(
+        x509.KeyUsage(digital_signature=True, content_commitment=True, key_encipherment=True, data_encipherment=False, key_agreement=False, key_cert_sign=False, crl_sign=False, encipher_only=False, decipher_only=False),
+        True
+    ).add_extension(
+        x509.BasicConstraints(ca=False, path_length=None),
+        True
+    ).add_extension(
+        x509.ExtendedKeyUsage([ExtendedKeyUsageOID.CLIENT_AUTH]),
+        False
+    )
+
+    if alternative_name:
+        cert = cert.add_extension(
+            x509.SubjectAlternativeName(
+                list(map(x509.DNSName, alternative_name))
+            ),
+            False
+        )
+
+    cert = cert.sign(ca_key, None if isinstance(ca_key, Ed25519PrivateKey) or isinstance(ca_key, Ed448PrivateKey) else hashes.SHA256())
+
+    output = output.with_suffix('.crt')
+
+    try:
+        mv_bak(output)
+    except FileNotFoundError:
+        pass
+    with umask(0o0133), atomic_write(output, overwrite=False, mode='wb') as cf:
+        logger.info('Writing new certificate to ‘%s’...', output)
+        cf.write(cert.public_bytes(serialization.Encoding.PEM))
+    logger.debug('Adjusting permissions for ‘%s’...', output)
+    os.chmod(output, 0o0444)
+
+def new_client(ca_cert, ca_key, key_type, clock_skew, validity, subject, alternative_name, sops, output):
+    key_file = output.with_suffix('.key')
+    cert_file = output.with_suffix('.crt')
+
+    key = None
+    try:
+        key = load_key(key_file)
+        logger.info('Successfully loaded privkey from ‘%s’', key_file)
+
+        if not key_type.aligned(key):
+            logger.warn('Private key ‘%s’ does not align with requested type %s', key_file, key_type)
+
+            try:
+                mv_bak(key_file)
+            except FileNotFoundError:
+                pass
+            try:
+                mv_bak(cert_file)
+            except FileNotFoundError:
+                pass
+
+            raise FileNotFoundError(f'Key does not align with requested type: {key_file}')
+    except FileNotFoundError:
+        key = write_genkey(key_type, sops, key_file)
+
+    csr = x509.CertificateSigningRequestBuilder().subject_name(x509.Name([
+        x509.NameAttribute(NameOID.COMMON_NAME, subject)
+    ]))
+    if alternative_name:
+        csr = csr.add_extension(
+            x509.SubjectAlternativeName(
+                list(map(x509.DNSName, alternative_name))
+            ),
+            False
+        )
+
+    return signcsr(
+        ca_cert=ca_cert,
+        ca_key=ca_key,
+        clock_skew=clock_skew,
+        validity=validity,
+        subject=None,
+        alternative_name=[],
+        ignore_alternative_names=False,
+        output=cert_file,
+        csr=csr.sign(
+            key,
+            None if isinstance(key, Ed25519PrivateKey) or isinstance(key, Ed448PrivateKey) else hashes.SHA256(),
+        ).public_bytes(serialization.Encoding.PEM)
+    )
+
+def to_pkcs12(random_password, filename, output):
+    key_file = filename.with_suffix('.key')
+    cert_file = filename.with_suffix('.crt')
+
+    if not output:
+        output = filename.with_suffix('.p12')
+
+    key = load_key(key_file)
+    logger.info('Successfully loaded privkey from ‘%s’', key_file)
+    cert = None
+    with open(cert_file, mode='rb') as fh:
+        cert = x509.load_pem_x509_certificate(fh.read())
+        logger.info('Successfully loaded certificate from ‘%s’', cert_file)
+
+    with umask(0o0177), atomic_write(output, overwrite=False, mode='wb') as fh:
+        logger.info('Writing to ‘%s’...', output)
+        common_name_attrs = cert.subject.get_attributes_for_oid(NameOID.COMMON_NAME)
+        if len(common_name_attrs) != 1:
+            raise InvalidParamsError('Invalid name structure in cert')
+        subject = common_name_attrs[0].value.lower()
+
+        pw = None
+        if not random_password:
+            pw2 = None
+            while not pw2 or pw2 != pw:
+                pw = getpass(prompt='Password: ')
+                if not pw:
+                    pw = None
+                    break
+                else:
+                    pw2 = getpass(prompt='Repeat password: ')
+        else:
+            from xkcdpass import xkcd_password as xp
+            ws = xp.generate_wordlist(wordfile=xp.locate_wordfile())
+            pw = xp.generate_xkcdpassword(ws, numwords=12)
+            print(f'Password: {pw}', file=sys.stderr)
+
+        encryption = None
+        if pw:
+            encryption = PrivateFormat.PKCS12.encryption_builder().kdf_rounds(
+                500000
+            ).key_cert_algorithm(
+                pkcs12.PBES.PBESv2SHA256AndAES256CBC
+            ).hmac_hash(
+                hashes.SHA256()
+            ).build(bytes(pw, 'utf-8'))
+        fh.write(pkcs12.serialize_key_and_certificates(
+            bytes(subject, 'utf-8'),
+            key,
+            cert,
+            None,
+            encryption,
+        ))
+    logger.debug('Adjusting permissions for ‘%s’...', output)
+    os.chmod(output, 0o0400)
+
+
+def main():
+    global logger
+    logger = logging.getLogger(__name__)
+    console_handler = logging.StreamHandler()
+    console_handler.setFormatter( logging.Formatter('[%(levelname)s](%(name)s): %(message)s') )
+    if sys.stderr.isatty():
+        console_handler.setFormatter( logging.Formatter('%(asctime)s [%(levelname)s](%(name)s): %(message)s') )
+    logger.addHandler(console_handler)
+
+    # log uncaught exceptions
+    def log_exceptions(type, value, tb):
+        global logger
+
+        logger.error(value)
+        sys.__excepthook__(type, value, tb) # calls default excepthook
+
+    sys.excepthook = log_exceptions
+
+
+    parser = argparse.ArgumentParser(prog='ca', formatter_class=argparse.ArgumentDefaultsHelpFormatter)
+    parser.add_argument('--verbosity', dest='log_level', action='append', type=int)
+    parser.add_argument('--verbose', '-v', dest='log_level', action='append_const', const=1)
+    parser.add_argument('--quiet', '-q', dest='log_level', action='append_const', const=-1)
+    subparsers = parser.add_subparsers(help='Subcommands', required=True)
+
+    subparser = subparsers.add_parser('init', aliases=['initca', 'init-ca', 'ca'], formatter_class=argparse.ArgumentDefaultsHelpFormatter)
+    subparser.add_argument('--ca-cert', type=Path, default=Path('ca.crt'))
+    subparser.add_argument('--ca-key', type=Path, default=Path('ca.key'))
+    subparser.add_argument('--key-type', type=KeyType.from_string, choices=list(KeyType), default=KeyType.ED448.value)
+    subparser.add_argument('--clock-skew', metavar='DURATION', type=duration, default=timedelta(minutes=5))
+    subparser.add_argument('--validity', metavar='DURATION', type=duration, default=timedelta(days=ceil(365.2425*10)))
+    subparser.add_argument('--sops', '--no-sops', action=BooleanAction, default=True)
+    subparser.add_argument('--subject', metavar='FQDN', type=ValidFQDN, required=True)
+    subparser.set_defaults(cmd=initca)
+
+    subparser = subparsers.add_parser('sign', aliases=['signcsr', 'sign-csr'], formatter_class=argparse.ArgumentDefaultsHelpFormatter)
+    subparser.add_argument('--ca-cert', type=Path, default=Path('ca.crt'))
+    subparser.add_argument('--ca-key', type=Path, default=Path('ca.key'))
+    subparser.add_argument('--clock-skew', metavar='DURATION', type=duration, default=timedelta(minutes=5))
+    subparser.add_argument('--validity', metavar='DURATION', type=duration, default=timedelta(days=ceil(365.2425*10)))
+    subparser.add_argument('--subject', metavar='CN', type=str, required=False)
+    subparser.add_argument('--ignore-alternative-names', '--no-ignore-alternative-names', action=BooleanAction, default=True)
+    subparser.add_argument('--alternative-name', metavar='CN', type=str, action='append')
+    subparser.add_argument('--output', type=Path, required=True)
+    subparser.add_argument('csr', metavar='FILE', type=argparse.FileType(mode='rb'))
+    subparser.set_defaults(cmd=signcsr)
+
+    subparser = subparsers.add_parser('new-client', aliases=['new', 'new-client', 'client'], formatter_class=argparse.ArgumentDefaultsHelpFormatter)
+    subparser.add_argument('--ca-cert', type=Path, default=Path('ca.crt'))
+    subparser.add_argument('--ca-key', type=Path, default=Path('ca.key'))
+    subparser.add_argument('--key-type', type=KeyType.from_string, choices=list(KeyType), default=KeyType.ED25519.value)
+    subparser.add_argument('--clock-skew', metavar='DURATION', type=duration, default=timedelta(minutes=5))
+    subparser.add_argument('--validity', metavar='DURATION', type=duration, default=timedelta(days=ceil(365.2425*10)))
+    subparser.add_argument('--sops', '--no-sops', action=BooleanAction, default=True)
+    subparser.add_argument('--subject', metavar='CN', type=str, required=True)
+    subparser.add_argument('--alternative-name', metavar='CN', type=str, action='append')
+    subparser.add_argument('--output', type=Path, required=True)
+    subparser.set_defaults(cmd=new_client)
+
+    subparser = subparsers.add_parser('pkcs12', aliases=['p12', 'pfx'], formatter_class=argparse.ArgumentDefaultsHelpFormatter)
+    subparser.add_argument('--random-password', '--no-random-password', action=BooleanAction, default=True)
+    subparser.add_argument('--output', type=Path)
+    subparser.add_argument('filename', metavar='BASENAME', type=Path)
+    subparser.set_defaults(cmd=to_pkcs12)
+
+    args = parser.parse_args()
+
+
+    LOG_LEVELS = [logging.DEBUG, logging.INFO, logging.WARNING, logging.ERROR, logging.CRITICAL]
+    DEFAULT_LOG_LEVEL = logging.INFO
+    log_level = LOG_LEVELS.index(DEFAULT_LOG_LEVEL)
+
+    for adjustment in args.log_level or ():
+        log_level = min(len(LOG_LEVELS) - 1, max(log_level - adjustment, 0))
+    logger.setLevel(LOG_LEVELS[log_level])
+
+
+    logger.debug('Using cryptography %s (%s)', cryptography_version, openssl.backend.openssl_version_text())
+
+
+    args.cmd(**{ k: v for k, v in vars(args).items() if k in signature(args.cmd).parameters.keys() })
+
+if __name__ == '__main__':
+    sys.exit(main())
diff --git a/tools/ca/setup.py b/tools/ca/setup.py
new file mode 100644
index 00000000..3342a7a6
--- /dev/null
+++ b/tools/ca/setup.py
@@ -0,0 +1,10 @@
+from setuptools import setup
+
+setup(name='ca',
+      packages=['ca'],
+      entry_points={
+          'console_scripts': [
+              'ca=ca.__main__:main'
+          ],
+      },
+)