diff --git a/README.md b/README.md index 3e354fb..c54d551 100644 --- a/README.md +++ b/README.md @@ -4,18 +4,43 @@ Python script to replace [MargTools](https://businessconnect.margis.si/output/#o ## Usage -Create the configuration file `~/.margfools` with the paths to your TLS private key and certificate in PEM format: +Run `margfools -h` for a synopsis of command‐line arguments. Allowed arguments are - [https://gcsign.example.com/BCSign/] - user-key = - user-cert = + margfools [-h] [-e {file,pkcs11}] [-k KEYFILE] [-c CERTFILE] [-i ] URL -Section name is the percent-decoded value of `baseURL` in +To use a signing key and certificate stored in PEM files, install `openssl` and run - bc-digsign://sign?accessToken=…&baseUrl=https%3a%2f%2fgcsign.example.com%2fBCSign%2f&…' + margfools -e file -k KEYFILE -c CERTFILE bc-digsign://sign?… -You can set `margfools` as the default program for `bc-digsign` URLs by copying the `margfools.desktop` file to `~/.local/share/applications/` and running +To sign using a PIV-II smartcard such as the Yubikey, install `pkcs11-tool` from [OpenSC](https://github.com/OpenSC/OpenSC) and run + + margfools -e pkcs11 -i bc-digsign://sign?… + +The script will prompt for the PIN to unlock the smartcard. To find the key ID, run + + pkcs11-tool -O + +To use `margfools` from the web app, set it as the default program for `x-scheme-handler/bc-digsign` URLs, or copy the `margfools.desktop` file to `~/.local/share/applications/` and run xdg-mime default margfools.desktop x-scheme-handler/bc-digsign -or by setting the default application in your browser. +For this to work, the script must be configured as described below. + +## Configuration + +Settings can be saved on a per‐site basis in `~/.margfools` using the [configparser](https://docs.python.org/3/library/configparser.html) format. + + [DEFAULT] + engine = pkcs11 + + [https://gcsign.example.org/BCSign/] + id = 02 + + [https://gcsign.example.com/BCSign/] + engine = file + keyfile = + certfile = + +All settings can be specified for all sites in the default section, or for individual sites. The section name should match the percent-decoded value of `baseURL` in + + bc-digsign://sign?…&baseUrl=https%3a%2f%2fgcsign.example.com%2fBCSign%2f&… diff --git a/margfools b/margfools index fed38bf..6f6d8d5 100755 --- a/margfools +++ b/margfools @@ -8,77 +8,119 @@ import os import pathlib import subprocess import sys -import traceback import urllib.parse +import getpass # use requests instead of urllib.request for keep-alive connection import requests -def sign(data, keyfile): - p = subprocess.run( - ['openssl', 'pkeyutl', '-sign', '-inkey', keyfile, '-pkeyopt', 'digest:sha256'], - input=base64.b64decode(data), - capture_output=True) +def init(args): + args.params = urllib.parse.parse_qs(args.url.query) + args.access_token = args.params["accessToken"][0] + args.start_token = args.params["startSigningToken"][0] + args.url = args.params['baseUrl'][0] + + # if missing, get options from section [url] in ~/.margfools + config = configparser.ConfigParser() + config.read(os.path.expanduser('~') + '/.margfools') + if not args.engine: + args.engine = config.get(args.url, 'engine', fallback='file') + + match args.engine: + case 'file': + if not args.keyfile: + args.keyfile = config.get(args.url, 'keyfile', fallback=None) + if not args.certfile: + args.certfile = config.get(args.url, 'certfile', fallback=None) + if not args.keyfile or not args.certfile: + raise Exception('key or certificate file not specified') + args.cert = ''.join(line.strip() for line in open(args.certfile) if not line.startswith('-----')) + case 'pkcs11': + if not args.id: + args.id = config.get(args.url, 'id', fallback=None) + if not args.id: + raise Exception('key ID not specified') + args.cert = base64.b64encode(subprocess.run(['pkcs11-tool', '--read-object', '--type', 'cert', '--id', args.id], capture_output=True).stdout).decode() + args.pin = getpass.getpass('PIN: ') + case '_': + raise Exception(f'invalid engine {args.engine}') + +def sign(b64data, args): + match args.engine: + case 'file': + if not args.keyfile: + raise Exception('keyfile not specified') + cmd = ['openssl', 'pkeyutl', '-sign', '-inkey', args.keyfile, '-pkeyopt', 'digest:sha256'] + env = None + data = base64.b64decode(b64data) + case 'pkcs11': + if not args.id: + raise Exception('key ID not specified') + digest_info = { # from RFC 3447 + 'MD2': '3020300c06082a864886f70d020205000410', + 'MD5': '3020300c06082a864886f70d020505000410', + 'SHA-1': '3021300906052b0e03021a05000414', + 'SHA-256': '3031300d060960864801650304020105000420', + 'SHA-384': '3041300d060960864801650304020205000430', + 'SHA-512': '3051300d060960864801650304020305000440' + } + cmd = ['pkcs11-tool', '--id', args.id, '-s', '-m', 'RSA-PKCS', '-p', 'env:PIN'] + env = {'PIN': args.pin} + data = bytes.fromhex(digest_info['SHA-256']) + base64.b64decode(b64data) + case '_': + raise Exception(f'invalid engine {args.engine}') + + p = subprocess.run(cmd, env=env, input=data, capture_output=True) + if p.returncode != 0: + raise Exception(f'could not sign data: {p.stderr.decode()}') + return base64.b64encode(p.stdout).decode() if __name__ == '__main__': parser = argparse.ArgumentParser(description='Fake the MargTools application.') parser.add_argument('url', type=urllib.parse.urlparse, help='bc-digsign:// url') - parser.add_argument('-k', '--user-key', type=pathlib.Path, help='key file') - parser.add_argument('-c', '--user-cert', type=pathlib.Path, help='certificate file') + parser.add_argument('-e', '--engine', choices=('file', 'pkcs11'), help='use key file or PKCS11 token?') + parser.add_argument('-k', '--keyfile', type=pathlib.Path, help='key file') + parser.add_argument('-c', '--certfile', type=pathlib.Path, help='certificate file') + parser.add_argument('-i', '--id', type=int, metavar='', help='key ID on PKCS11 token') args = parser.parse_args() try: - # parse query string - params = urllib.parse.parse_qs(args.url.query) - url = params['baseUrl'][0] - token = params['accessToken'][0] - - # if missing, get user key and cert from section [url] in ~/.margfools - config = configparser.ConfigParser() - config.read(os.path.expanduser('~') + '/.margfools') - if not args.user_key: - args.user_key = config.get(url, 'user-key') - if not args.user_cert: - args.user_cert = config.get(url, 'user-cert') - if not args.user_key or not args.user_cert: - print('user key and/or certificate not specified', file=sys.stderr) - sys.exit(1) - - user_keyfile = args.user_key - user_cert = ''.join(line.strip() for line in open(args.user_cert) if not line.startswith('-----')) + # parse query string and load certificates + init(args) session = requests.Session() - headers={'Authorization': f'Bearer {token}'} + headers = {'Authorization': f'Bearer {args.access_token}'} # delete old signing session - r = session.delete(f'{url}/signatures/{params["startSigningToken"][0]}', headers=headers) + r = session.delete(f'{args.url}/signatures/{args.params["startSigningToken"][0]}', headers=headers) # register a certificate or sign a document, makes no difference to us - if params.get('registerCertificate'): + if args.params.get('registerCertificate'): q = {'registerCertificate': 1} else: - q = {'documentId': [i for i in params['documentId'][0].split(',')]} + q = {'documentId': [i for i in args.params['documentId'][0].split(',')]} qs = urllib.parse.urlencode(q, doseq=True) - r = session.post(f'{url}/signatures?{qs}', headers=headers) + r = session.post(f'{args.url}/signatures?{qs}', headers=headers) # get signature request and mix in my secrets and publics request = json.loads(r.text) - request['AuthenticationToken'] = token - request['CertificatePublicKey'] = user_cert + request['AuthenticationToken'] = args.access_token + request['CertificatePublicKey'] = args.cert # keep signing whatever they send us while True: for name in ('AttachmentHashes', 'XmlHashes'): - if request.get(name) is not None: - request[f'Signed{name}'] = [sign(e, user_keyfile) for e in request[name]] + if values := request.get(name, []): + request[f'Signed{name}'] = [sign(v, args) for v in values] - r = session.put(f'{url}signatures/{request["SignatureRequestId"]}', + r = session.put(f'{args.url}signatures/{request["SignatureRequestId"]}', headers=headers | {'Content-Type': 'application/json; charset=utf-8'}, data=json.dumps(request).encode()) if not r.text: break request |= json.loads(r.text) - except: - traceback.print_exc() + except Exception as ex: + print(f'error: {ex}', file=sys.stderr) + input('press enter to exit') # don’t close terminal immediately on fail