Added self-signed SSL certificate generator

sbapp/sideband/certgen.py

@@ -0,0 +1,79 @@
+KEY_PASSPHRASE = None
+LOADED_KEY     = None
+
+import os
+import RNS
+import datetime
+from cryptography import x509
+from cryptography.x509.oid import NameOID
+from cryptography.hazmat.primitives import hashes
+from cryptography.hazmat.primitives import serialization
+from cryptography.hazmat.primitives.asymmetric import ec
+from cryptography.hazmat.primitives.serialization import load_pem_private_key
+
+from cryptography import __version__ as cryptography_version_str
+try:
+    cryptography_major_version = int(cryptography_version_str.split(".")[0])
+except:
+    RNS.log(f"Could not determine PyCA/cryptography version: {e}", RNS.LOG_ERROR)
+    RNS.log(f"Assuming recent version with automatic backend selection", RNS.LOG_ERROR)
+
+def get_key(key_path, force_reload=False):
+    KEY_PATH = key_path
+    key = None
+    if LOADED_KEY != None and not force_reload:
+        return LOADED_KEY
+    elif os.path.isfile(KEY_PATH):
+        with open(KEY_PATH, "rb") as f:
+            key = load_pem_private_key(f.read(), KEY_PASSPHRASE)
+    else:
+        if cryptography_major_version > 3:
+            key = ec.generate_private_key(curve=ec.SECP256R1())
+        else:
+            from cryptography.hazmat.backends import default_backend
+            key = ec.generate_private_key(curve=ec.SECP256R1(), backend=default_backend())
+
+        if KEY_PASSPHRASE == None:
+            key_encryption = serialization.NoEncryption()
+        else:
+            key_encryption = serialization.BestAvailableEncryption(KEY_PASSPHRASE)
+
+        with open(KEY_PATH, "wb") as f:
+            f.write(key.private_bytes(
+                encoding=serialization.Encoding.PEM,
+                format=serialization.PrivateFormat.PKCS8,
+                encryption_algorithm=key_encryption))
+
+    return key
+
+def gen_cert(cert_path, key):
+    CERT_PATH = cert_path
+    cert_attrs = [x509.NameAttribute(NameOID.COUNTRY_NAME, "NA"),
+                  x509.NameAttribute(NameOID.STATE_OR_PROVINCE_NAME, "None"),
+                  x509.NameAttribute(NameOID.LOCALITY_NAME, "Earth"),
+                  x509.NameAttribute(NameOID.ORGANIZATION_NAME, "Sideband"),
+                  x509.NameAttribute(NameOID.COMMON_NAME, "Sideband Repository")]
+
+    issuer  = x509.Name(cert_attrs)
+    subject = issuer
+
+    cb = x509.CertificateBuilder()
+    cb = cb.subject_name(subject)
+    cb = cb.issuer_name(issuer)
+    cb = cb.public_key(key.public_key())
+    cb = cb.serial_number(x509.random_serial_number())
+    cb = cb.not_valid_before(datetime.datetime.now(datetime.timezone.utc)+datetime.timedelta(days=-14))
+    cb = cb.not_valid_after(datetime.datetime.now(datetime.timezone.utc)+datetime.timedelta(days=3652))
+    cb = cb.add_extension(x509.SubjectAlternativeName([x509.DNSName("localhost")]), critical=False)
+    if cryptography_major_version > 3:
+        cert = cb.sign(key, hashes.SHA256())
+    else:
+        from cryptography.hazmat.backends import default_backend
+        cert = cb.sign(key, hashes.SHA256(), backend=default_backend())
+
+    with open(CERT_PATH, "wb") as f:
+        f.write(cert.public_bytes(serialization.Encoding.PEM))
+
+def ensure_certificate(key_path, cert_path):
+    gen_cert(cert_path, get_key(key_path))
+    return cert_path