From 1929625c171be66b4f29da31eb6b5fcbebefd820 Mon Sep 17 00:00:00 2001
From: Timotej Lazar <timotej.lazar@araneo.si>
Date: Sun, 12 Nov 2023 18:13:46 +0100
Subject: [PATCH] First commit

Not really but really.
---
 margfools | 83 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 83 insertions(+)
 create mode 100755 margfools

diff --git a/margfools b/margfools
new file mode 100755
index 0000000..55bbbed
--- /dev/null
+++ b/margfools
@@ -0,0 +1,83 @@
+#!/usr/bin/env python3
+
+import argparse
+import base64
+import configparser
+import json
+import os
+import pathlib
+import subprocess
+import sys
+import traceback
+import urllib.parse
+
+# 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)
+    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')
+    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('-----'))
+
+        session = requests.Session()
+        headers={'Authorization': f'Bearer {token}'}
+
+        # delete old signing session
+        r = session.delete(f'{url}/signatures/{params["startSigningToken"][0]}', headers=headers)
+
+        # register a certificate or sign a document, makes no difference to us
+        if params.get('registerCertificate'):
+            q = {'registerCertificate': 1}
+        else:
+            q = {'documentId': params['documentId'][0]}
+        r = session.post(f'{url}/signatures?{urllib.parse.urlencode(q)}', headers=headers)
+
+        # get signature request and mix in my secrets and publics
+        request = json.loads(r.text)
+        request['AuthenticationToken'] = token
+        request['CertificatePublicKey'] = user_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]]
+
+            r = session.put(f'{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()