move cert serialization to cryptography

CHANGELOG.md

@@ -38,7 +38,7 @@ If you depend on these features, please raise your voice in
 ### Full Changelog
 
 * New Proxy Core based on sans-io pattern (@mhils)
-* Use cryptography to generate certificates, not pyOpenSSL (@mhils)
+* Use pyca/cryptography to generate certificates, not pyOpenSSL (@mhils)
 * Remove the legacy protocol stack (@Kriechi)
 * Remove all deprecated pathod and pathoc tools and modules (@Kriechi)
 * --- TODO: add new PRs above this line ---

mitmproxy/certs.py

@@ -4,18 +4,20 @@ import ipaddress
 import os
 import ssl
 import sys
+from dataclasses import dataclass
 from pathlib import Path
 from typing import Tuple, Optional, Union, Dict, List
 
 from cryptography import x509
-from cryptography.hazmat.primitives import hashes
+from cryptography.hazmat.primitives import hashes, serialization
 from cryptography.hazmat.primitives.asymmetric import rsa
+from cryptography.hazmat.primitives.serialization import pkcs12
+from cryptography.x509 import NameOID, ExtendedKeyUsageOID
 from pyasn1.codec.der.decoder import decode
 from pyasn1.error import PyAsn1Error
 from pyasn1.type import univ, constraint, char, namedtype, tag
 
 import OpenSSL
-from cryptography.x509 import NameOID, ExtendedKeyUsageOID
 from mitmproxy.coretypes import serializable
 
 # Default expiry must not be too long: https://github.com/mitmproxy/mitmproxy/issues/815
@@ -40,13 +42,17 @@ rD693XKIHUCWOjMh1if6omGXKHH40QuME2gNa50+YPn1iYDl88uDbbMCAQI=
 """
 
 
-def create_ca(organization: str, cn: str, key_size: int) -> Tuple[OpenSSL.crypto.PKey, OpenSSL.crypto.X509]:
+def create_ca(
+        organization: str,
+        cn: str,
+        key_size: int,
+) -> Tuple[rsa.RSAPrivateKeyWithSerialization, x509.Certificate]:
     now = datetime.datetime.now()
 
     private_key = rsa.generate_private_key(
         public_exponent=65537,
         key_size=key_size,
-    )
+    )  # type: ignore
     name = x509.Name([
         x509.NameAttribute(NameOID.COMMON_NAME, cn),
         x509.NameAttribute(NameOID.ORGANIZATION_NAME, organization)
@@ -73,8 +79,8 @@ def create_ca(organization: str, cn: str, key_size: int) -> Tuple[OpenSSL.crypto
             decipher_only=False,
         ), critical=True)
     builder = builder.add_extension(x509.SubjectKeyIdentifier.from_public_key(private_key.public_key()), critical=False)
-    cert = builder.sign(private_key=private_key, algorithm=hashes.SHA256())
-    return OpenSSL.crypto.PKey.from_cryptography_key(private_key), OpenSSL.crypto.X509.from_cryptography(cert)
+    cert = builder.sign(private_key=private_key, algorithm=hashes.SHA256())  # type: ignore
+    return private_key, cert
 
 
 def dummy_cert(
@@ -99,27 +105,31 @@ def dummy_cert(
     XX_cacert: x509.Certificate = cacert.to_cryptography()
     XX_commonname: Optional[str] = commonname.decode("idna") if commonname else None
     XX_organization: Optional[str] = organization.decode() if organization else None
-    XX_sans: Optional[List[str]] = [x.decode("ascii") for x in sans]
-
-    now = datetime.datetime.now()
+    XX_sans: List[str] = [x.decode("ascii") for x in sans]
 
     builder = x509.CertificateBuilder()
+    builder = builder.issuer_name(XX_cacert.subject)
+    builder = builder.add_extension(x509.ExtendedKeyUsage([ExtendedKeyUsageOID.SERVER_AUTH]), critical=False)
+    builder = builder.public_key(XX_cacert.public_key())
+
+    now = datetime.datetime.now()
     builder = builder.not_valid_before(now - datetime.timedelta(days=2))
     builder = builder.not_valid_after(now + CERT_EXPIRY)
-    builder = builder.issuer_name(XX_cacert.subject)
 
     subject = []
     is_valid_commonname = (
-            commonname is not None and len(commonname) < 64
+            XX_commonname is not None and len(XX_commonname) < 64
     )
     if is_valid_commonname:
+        assert XX_commonname is not None
         subject.append(x509.NameAttribute(NameOID.COMMON_NAME, XX_commonname))
-    if organization is not None:
+    if XX_organization is not None:
+        assert XX_organization is not None
         subject.append(x509.NameAttribute(NameOID.ORGANIZATION_NAME, XX_organization))
     builder = builder.subject_name(x509.Name(subject))
     builder = builder.serial_number(x509.random_serial_number())
 
-    ss = []
+    ss: List[x509.GeneralName] = []
     for x in XX_sans:
         try:
             ip = ipaddress.ip_address(x)
@@ -129,18 +139,17 @@ def dummy_cert(
             ss.append(x509.IPAddress(ip))
     # RFC 5280 §4.2.1.6: subjectAltName is critical if subject is empty.
     builder = builder.add_extension(x509.SubjectAlternativeName(ss), critical=not is_valid_commonname)
-    builder = builder.add_extension(x509.ExtendedKeyUsage([ExtendedKeyUsageOID.SERVER_AUTH]), critical=False)
-    builder = builder.public_key(XX_cacert.public_key())
-    cert = builder.sign(private_key=XX_privkey, algorithm=hashes.SHA256())
+    cert = builder.sign(private_key=XX_privkey, algorithm=hashes.SHA256())  # type: ignore
     return Cert(OpenSSL.crypto.X509.from_cryptography(cert))
 
 
+@dataclass
 class CertStoreEntry:
-
-    def __init__(self, cert, privatekey, chain_file):
-        self.cert = cert
-        self.privatekey = privatekey
-        self.chain_file = chain_file
+    cert: OpenSSL.crypto.X509
+    # cert: x509.Certificate
+    privatekey: OpenSSL.crypto.PKey
+    # privatekey: rsa.RSAPrivateKey
+    chain_file: str
 
 
 TCustomCertId = bytes  # manually provided certs (e.g. mitmproxy's --certs)
@@ -240,44 +249,45 @@ class CertStore:
         organization = organization or basename
         cn = cn or basename
 
+        key: rsa.RSAPrivateKeyWithSerialization
+        ca: x509.Certificate
         key, ca = create_ca(organization=organization, cn=cn, key_size=key_size)
         # Dump the CA plus private key
         with CertStore.umask_secret(), (path / f"{basename}-ca.pem").open("wb") as f:
-            f.write(
-                OpenSSL.crypto.dump_privatekey(
-                    OpenSSL.crypto.FILETYPE_PEM,
-                    key))
-            f.write(
-                OpenSSL.crypto.dump_certificate(
-                    OpenSSL.crypto.FILETYPE_PEM,
-                    ca))
+            f.write(key.private_bytes(
+                encoding=serialization.Encoding.PEM,
+                format=serialization.PrivateFormat.TraditionalOpenSSL,
+                encryption_algorithm=serialization.NoEncryption(),
+            ))
+            f.write(ca.public_bytes(serialization.Encoding.PEM))
 
         # Dump the certificate in PEM format
         with (path / f"{basename}-ca-cert.pem").open("wb") as f:
-            f.write(
-                OpenSSL.crypto.dump_certificate(
-                    OpenSSL.crypto.FILETYPE_PEM,
-                    ca))
+            f.write(ca.public_bytes(serialization.Encoding.PEM))
 
         # Create a .cer file with the same contents for Android
         with (path / f"{basename}-ca-cert.cer").open("wb") as f:
-            f.write(
-                OpenSSL.crypto.dump_certificate(
-                    OpenSSL.crypto.FILETYPE_PEM,
-                    ca))
+            f.write(ca.public_bytes(serialization.Encoding.PEM))
 
         # Dump the certificate in PKCS12 format for Windows devices
         with (path / f"{basename}-ca-cert.p12").open("wb") as f:
-            p12 = OpenSSL.crypto.PKCS12()
-            p12.set_certificate(ca)
-            f.write(p12.export())
+            f.write(pkcs12.serialize_key_and_certificates(  # type: ignore
+                name=basename.encode(),
+                key=None,
+                cert=ca,
+                cas=None,
+                encryption_algorithm=serialization.NoEncryption(),
+            ))
 
         # Dump the certificate and key in a PKCS12 format for Windows devices
         with CertStore.umask_secret(), (path / f"{basename}-ca.p12").open("wb") as f:
-            p12 = OpenSSL.crypto.PKCS12()
-            p12.set_certificate(ca)
-            p12.set_privatekey(key)
-            f.write(p12.export())
+            f.write(pkcs12.serialize_key_and_certificates(  # type: ignore
+                name=basename.encode(),
+                key=key,
+                cert=ca,
+                cas=None,
+                encryption_algorithm=serialization.NoEncryption(),
+            ))
 
         with (path / f"{basename}-dhparam.pem").open("wb") as f:
             f.write(DEFAULT_DHPARAM)
@@ -386,8 +396,10 @@ class _GeneralName(univ.Choice):
 
 class _GeneralNames(univ.SequenceOf):
     componentType = _GeneralName()
-    sizeSpec = univ.SequenceOf.sizeSpec + \
+    sizeSpec = (
+            univ.SequenceOf.sizeSpec +
             constraint.ValueSizeConstraint(1, 1024)
+    )
 
 
 class Cert(serializable.Serializable):

test/mitmproxy/test_certs.py

@@ -1,6 +1,4 @@
-import gc
 import os
-import secrets
 
 import pytest