mailcow-dockerized/helper-scripts/generate_caa_record.py
2023-10-23 19:44:28 +02:00

123 lines
6.5 KiB
Python
Executable File

#!/usr/bin/env python3
# Based on github.com/diafygi/acme-tiny, original copyright:
# Copyright Daniel Roesler, under MIT license, see LICENSE at github.com/diafygi/acme-tiny
import argparse, subprocess, json, os, sys, base64, binascii, time, hashlib, re, copy, textwrap, logging
try:
from urllib.request import urlopen, Request # Python 3
except ImportError: # pragma: no cover
from urllib2 import urlopen, Request # Python 2
DEFAULT_DIRECTORY_URL = "https://acme-v02.api.letsencrypt.org/directory"
LOGGER = logging.getLogger(__name__)
LOGGER.addHandler(logging.StreamHandler())
LOGGER.setLevel(logging.INFO)
def get_id(account_key, log=LOGGER, directory_url=DEFAULT_DIRECTORY_URL, contact=None):
directory, acct_headers, alg, jwk = None, None, None, None # global variables
# helper functions - base64 encode for jose spec
def _b64(b):
return base64.urlsafe_b64encode(b).decode('utf8').replace("=", "")
# helper function - run external commands
def _cmd(cmd_list, stdin=None, cmd_input=None, err_msg="Command Line Error"):
proc = subprocess.Popen(cmd_list, stdin=stdin, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
out, err = proc.communicate(cmd_input)
if proc.returncode != 0:
raise IOError("{0}\n{1}".format(err_msg, err))
return out
# helper function - make request and automatically parse json response
def _do_request(url, data=None, err_msg="Error", depth=0):
try:
resp = urlopen(Request(url, data=data, headers={"Content-Type": "application/jose+json", "User-Agent": "acme-tiny"}))
resp_data, code, headers = resp.read().decode("utf8"), resp.getcode(), resp.headers
except IOError as e:
resp_data = e.read().decode("utf8") if hasattr(e, "read") else str(e)
code, headers = getattr(e, "code", None), {}
try:
resp_data = json.loads(resp_data) # try to parse json results
except ValueError:
pass # ignore json parsing errors
if depth < 100 and code == 400 and resp_data['type'] == "urn:ietf:params:acme:error:badNonce":
raise IndexError(resp_data) # allow 100 retrys for bad nonces
if code not in [200, 201, 204]:
raise ValueError("{0}:\nUrl: {1}\nData: {2}\nResponse Code: {3}\nResponse: {4}".format(err_msg, url, data, code, resp_data))
return resp_data, code, headers
# helper function - make signed requests
def _send_signed_request(url, payload, err_msg, depth=0):
payload64 = "" if payload is None else _b64(json.dumps(payload).encode('utf8'))
new_nonce = _do_request(directory['newNonce'])[2]['Replay-Nonce']
protected = {"url": url, "alg": alg, "nonce": new_nonce}
protected.update({"jwk": jwk} if acct_headers is None else {"kid": acct_headers['Location']})
protected64 = _b64(json.dumps(protected).encode('utf8'))
protected_input = "{0}.{1}".format(protected64, payload64).encode('utf8')
out = _cmd(["openssl", "dgst", "-sha256", "-sign", account_key], stdin=subprocess.PIPE, cmd_input=protected_input, err_msg="OpenSSL Error")
data = json.dumps({"protected": protected64, "payload": payload64, "signature": _b64(out)})
try:
return _do_request(url, data=data.encode('utf8'), err_msg=err_msg, depth=depth)
except IndexError: # retry bad nonces (they raise IndexError)
return _send_signed_request(url, payload, err_msg, depth=(depth + 1))
# helper function - poll until complete
def _poll_until_not(url, pending_statuses, err_msg):
result, t0 = None, time.time()
while result is None or result['status'] in pending_statuses:
assert (time.time() - t0 < 3600), "Polling timeout" # 1 hour timeout
time.sleep(0 if result is None else 2)
result, _, _ = _send_signed_request(url, None, err_msg)
return result
# parse account key to get public key
log.info("Parsing account key...")
out = _cmd(["openssl", "rsa", "-in", account_key, "-noout", "-text"], err_msg="OpenSSL Error")
pub_pattern = r"modulus:[\s]+?00:([a-f0-9\:\s]+?)\npublicExponent: ([0-9]+)"
pub_hex, pub_exp = re.search(pub_pattern, out.decode('utf8'), re.MULTILINE|re.DOTALL).groups()
pub_exp = "{0:x}".format(int(pub_exp))
pub_exp = "0{0}".format(pub_exp) if len(pub_exp) % 2 else pub_exp
alg, jwk = "RS256", {
"e": _b64(binascii.unhexlify(pub_exp.encode("utf-8"))),
"kty": "RSA",
"n": _b64(binascii.unhexlify(re.sub(r"(\s|:)", "", pub_hex).encode("utf-8"))),
}
accountkey_json = json.dumps(jwk, sort_keys=True, separators=(',', ':'))
thumbprint = _b64(hashlib.sha256(accountkey_json.encode('utf8')).digest())
# get the ACME directory of urls
log.info("Getting directory...")
directory, _, _ = _do_request(directory_url, err_msg="Error getting directory")
log.info("Directory found!")
# create account and get the global key identifier
log.info("Registering account...")
reg_payload = {"termsOfServiceAgreed": True} if contact is None else {"termsOfServiceAgreed": True, "contact": contact}
account, code, acct_headers = _send_signed_request(directory['newAccount'], reg_payload, "Error registering")
log.info("Registered!" if code == 201 else "Already registered!")
return acct_headers['Location']
def main(argv=None):
parser = argparse.ArgumentParser(
formatter_class=argparse.RawDescriptionHelpFormatter,
description=textwrap.dedent("""\
Generate a CAA record for Mailcow.
Example Usage: python mailcow_gencaa.py --account-key data/assets/ssl/acme/account.pem
""")
)
parser.add_argument("--account-key", required=True, help="path to your Let's Encrypt account private key")
parser.add_argument("--quiet", action="store_const", const=logging.ERROR, help="suppress output except for errors")
parser.add_argument("--directory-url", default=DEFAULT_DIRECTORY_URL, help="certificate authority directory url, default is Let's Encrypt")
parser.add_argument("--contact", metavar="CONTACT", default=None, nargs="*", help="Contact details (e.g. mailto:aaa@bbb.com) for your account-key")
args = parser.parse_args(argv)
LOGGER.setLevel(args.quiet or LOGGER.level)
id = get_id(args.account_key, log=LOGGER, directory_url=args.directory_url, contact=args.contact)
print("Use this as your CAA record:")
print('issue 128 "letsencrypt.org;accounturi={}"'.format(id))
if __name__ == "__main__": # pragma: no cover
main(sys.argv[1:])