#!/usr/bin/env python3 ## Call with "--help" for documentation. import argparse, configparser, itertools, stat, os, os.path, sys, subprocess, datetime ## Helper functions def readConfig(fname, defSection = 'DEFAULT'): config = configparser.ConfigParser() with open(fname) as file: stream = itertools.chain(("["+defSection+"]\n",), file) config.read_file(stream) return config def certfile(name): global config return os.path.join(config['dirs']['certs'], name + ".crt" ) def keyfile(name): global config return os.path.join(config['dirs']['keys'], name + ".key") def make_backup(fname): if os.path.exists(fname): backupname = os.path.basename(fname) + "." + str(datetime.date.today()) i = 0 while True: backupfile = os.path.join(config['dirs']['backups'], backupname + "." + str(i)) if not os.path.exists(backupfile): os.rename(fname, backupfile) break elif i >= 100: print("Somehow it's really hard to find a name for the backup file...") i += 1 assert not os.path.exists(fname) def trigger_hook(hook): global config exe = config['hooks'][hook] if exe is not None: subprocess.check_call([exe]) def key_mtime(name): return datetime.datetime.fromtimestamp(os.stat(keyfile(name)).st_mtime) def cert_expiry(name): from certcheck import cert_expiry_date return cert_expiry_date(certfile(name)) ## Work functions, operating on file names ## The interesting work def acme(keyfilename, certfilename, domains): global config accountkey = config['acme']['account-key'] csrfilename = certfilename + '.csr.tmp' assert os.path.exists(keyfilename) assert accountkey # Generating the CSR is done by a shell script exe = os.path.join(os.path.dirname(__file__), 'gencsr') csr = subprocess.check_output([exe, keyfilename] + domains) assert not os.path.exists(csrfilename) with open(csrfilename, 'wb') as file: file.write(csr) # call acme-tiny as a script acme_tiny = os.path.join(config['acme']['acme-tiny'], 'acme_tiny.py') signed_crt = subprocess.check_output(["python", acme_tiny, "--quiet", "--account-key", accountkey, "--csr", csrfilename, "--acme-dir", config['acme']['challenge-dir']]) # save new certificate make_backup(certfilename) with open(certfilename, 'wb') as f: f.write(signed_crt) # clean up os.remove(csrfilename) def openssl_genrsa(keyfilename): with subprocess.Popen(["openssl", "genrsa", str(int(config['DEFAULT']['key-length']))], stdout=subprocess.PIPE, stderr=subprocess.PIPE) as f: (stdout, stderr) = f.communicate() if f.returncode: sys.stderr.write(stderr) raise Exception("Error while generating private key") # Now we have a key, save it. This should never overwrite anything. assert not os.path.exists(keyfilename) with open(keyfilename, 'wb') as f: f.write(stdout) ## High-level functions, operating on nice key names def request_cert(name): global config if not os.path.exists(keyfile(name)): raise Exception("No such key: {}".format(name)) domains = config['DEFAULT']['domains'].split() print("Obtaining certificate '{}' for domains: {}".format(name, ' '.join(domains))) acme(keyfile(name), certfile(name), domains) def generate_key(name): print("Generating new private key '{}'".format(name)) openssl_genrsa(keyfile(name)) def check_staging(live, staging): '''Returns 0 if nothing was done, 1 if a stage key is present but has to be kept, 2 is a stage key was unstaged.''' if not os.path.exists(keyfile(staging)): return 0 staging_time = datetime.timedelta(hours = int(config['timing'].get('staging-hours', 0))) key_age = datetime.datetime.now() - key_mtime(staging) if key_age < staging_time: return 1 print("Unstaging '{}' to '{}'".format(staging, live)) # unstage the key! make_backup(keyfile(live)) os.rename(keyfile(staging), keyfile(live)) make_backup(certfile(live)) os.rename(certfile(staging), certfile(live)) return 2 def auto_renewal(live, staging): '''Returns 0 if nothing was done, 1 if only certs were changed, 2 if certs and keys were changed.''' max_key_age = datetime.timedelta(days = int(config['timing']['max-key-age-days'])) renew_cert_time = datetime.timedelta(days = int(config['timing']['renew-cert-before-expiry-days'])) # determine what to do now = datetime.datetime.now() key_age = now - key_mtime(live) cert_validity = cert_expiry(live) - now need_new_key = key_age >= max_key_age need_new_cert = cert_validity <= renew_cert_time if need_new_cert and key_age + renew_cert_time >= max_key_age: # We are about to request a new certificate, and within , we need a new key: Get the new key now need_new_key = True # Do it if need_new_key: generate_key(staging) request_cert(staging) check_staging(live, staging) # we may want to immediately enable the new key & cert return 2 elif need_new_cert: request_cert(live) return 1 else: return 0 ## Main if __name__ == "__main__": # allow overwriting some values on the command-line parser = argparse.ArgumentParser(description='Generate and (automatically) renew certificates, optionally providing staging for new keys') parser.add_argument("-c", "--config", dest="config", help="The configuration file") parser.add_argument("-k", "--hooks", dest="hooks", action="store_true", help="Trigger hooks.") parser.add_argument("action", metavar='ACTION', nargs=1, help="The action to perform. Possible values: init, renew, cron") args = parser.parse_args() # read config, sanity check if not os.path.isfile(args.config): raise Exception("The config file does not exist: "+args.config) global config config = readConfig(args.config) live = config['files']['live'] staging = config['files']['staging'] if args.action[0] == 'renew': request_cert(live) if os.path.exists(keyfile(staging)) and os.path.exists(certfile(staging)): request_cert(staging) # trigger the "new cert" hook if args.hooks: trigger_hook('post-certchange') elif args.action[0] == 'cron': # First, check if we need to unstage a staging key unstaged = check_staging(live, staging) if unstaged >= 1: # A staging key is present, do *not* check for renewal if unstaged >= 2 and args.hooks: # trigger all the hooks trigger_hook('post-certchange') trigger_hook('post-keychange') else: # Check if we need to renew anything renewed = auto_renewal(live, staging) if args.hooks: if renewed >= 1: trigger_hook('post-certchange') if renewed >= 2: trigger_hook('post-keychange') elif args.action[0] == 'init': # create directories with appropriate permissions try: os.makedirs(config['dirs']['certs'], mode = 0o755, exist_ok = True) os.makedirs(config['dirs']['keys'], mode = 0o710, exist_ok = True) os.makedirs(config['dirs']['backups'], mode = 0o700, exist_ok = True) except OSError: pass # if necessary, generate ACME account key accountkey = config['acme']['account-key'] if not os.path.exists(accountkey): print("Generating new ACME key") openssl_genrsa(accountkey) # if necessary, generate key + certificate live = config['files']['live'] if not os.path.exists(keyfile(live)): generate_key(live) request_cert(live) if args.hooks: trigger_hook('post-certchange') trigger_hook('post-keychange') else: raise Exception("Unknown action {}".format(args.action))