fixes #608 -- added mldsa cert tests

limbo-schema.json

@@ -24,7 +24,8 @@
         "pedantic-rfc5280",
         "rfc5280-incompatible-with-webpki",
         "denial-of-service",
-        "has-crl"
+        "has-crl",
+        "has-mldsa"
       ],
       "title": "Feature",
       "type": "string"
@@ -156,6 +157,9 @@
         "DSA_WITH_SHA512",
         "ED25519",
         "ED448",
+        "ML_DSA_44",
+        "ML_DSA_65",
+        "ML_DSA_87",
         "GOSTR3411_94_WITH_3410_2001",
         "GOSTR3410_2012_WITH_3411_2012_256",
         "GOSTR3410_2012_WITH_3411_2012_512"

limbo/assets.py

@@ -13,6 +13,7 @@
 
 from cryptography import x509
 from cryptography.hazmat.primitives import serialization
+from cryptography.hazmat.primitives.asymmetric import dsa, ec, rsa
 from cryptography.hazmat.primitives.asymmetric.types import CertificateIssuerPrivateKeyTypes
 from cryptography.x509 import ExtensionType
 
@@ -51,9 +52,17 @@ class CertificatePair(Certificate):
 
     @cached_property
     def key_pem(self) -> str:
+        # NOTE: Not every key type has a "traditional" (i.e. non-PKCS#8)
+        # serialization; ML-DSA and EdDSA keys are PKCS#8 only.
+        match self.key:
+            case dsa.DSAPrivateKey() | ec.EllipticCurvePrivateKey() | rsa.RSAPrivateKey():
+                format = serialization.PrivateFormat.TraditionalOpenSSL
+            case _:
+                format = serialization.PrivateFormat.PKCS8
+
         return self.key.private_bytes(
             encoding=serialization.Encoding.PEM,
-            format=serialization.PrivateFormat.TraditionalOpenSSL,
+            format=format,
             encryption_algorithm=serialization.NoEncryption(),
         ).decode()
 

limbo/models.py

@@ -90,6 +90,9 @@ class SignatureAlgorithm(StrEnum):
     DSA_WITH_SHA512 = "DSA_WITH_SHA512"
     ED25519 = "ED25519"
     ED448 = "ED448"
+    ML_DSA_44 = "ML_DSA_44"
+    ML_DSA_65 = "ML_DSA_65"
+    ML_DSA_87 = "ML_DSA_87"
     GOSTR3411_94_WITH_3410_2001 = "GOSTR3411_94_WITH_3410_2001"
     GOSTR3410_2012_WITH_3411_2012_256 = "GOSTR3410_2012_WITH_3411_2012_256"
     GOSTR3410_2012_WITH_3411_2012_512 = "GOSTR3410_2012_WITH_3411_2012_512"
@@ -221,6 +224,11 @@ class Feature(StrEnum):
     Tests that use Certificate Revocation Lists (CRLs).
     """
 
+    has_mldsa = "has-mldsa"
+    """
+    Tests that use ML-DSA keys or signatures, per RFC 9881.
+    """
+
 
 class Importance(StrEnum):
     """

limbo/testcases/__init__.py

@@ -10,6 +10,7 @@
 from .pathlen import *  # noqa: F403
 from .pathological import *  # noqa: F403
 from .rfc5280 import *  # noqa: F403
+from .rfc9881 import *  # noqa: F403
 from .webpki import *  # noqa: F403
 
 __all__ = [

limbo/testcases/_core.py

@@ -8,7 +8,7 @@
 
 from cryptography import x509
 from cryptography.hazmat.primitives import hashes, serialization
-from cryptography.hazmat.primitives.asymmetric import ec
+from cryptography.hazmat.primitives.asymmetric import ec, ed448, ed25519, mldsa
 from cryptography.hazmat.primitives.asymmetric.types import CertificateIssuerPrivateKeyTypes
 
 from limbo.assets import (
@@ -32,6 +32,24 @@
 logger = logging.getLogger(__name__)
 
 
+def signature_hash(key: CertificateIssuerPrivateKeyTypes) -> hashes.SHA256 | None:
+    """
+    Returns the hash algorithm to sign with under the given key, or `None` for
+    key types that don't take a separate digest (EdDSA and ML-DSA).
+    """
+    match key:
+        case (
+            ed25519.Ed25519PrivateKey()
+            | ed448.Ed448PrivateKey()
+            | mldsa.MLDSA44PrivateKey()
+            | mldsa.MLDSA65PrivateKey()
+            | mldsa.MLDSA87PrivateKey()
+        ):
+            return None
+        case _:
+            return hashes.SHA256()
+
+
 class Builder:
     def _ca(
         self,
@@ -116,9 +134,9 @@ def _ca(
             builder = builder.add_extension(extra_extension.ext, critical=extra_extension.critical)
 
         if parent:
-            cert = builder.sign(parent.key, algorithm=hashes.SHA256())
+            cert = builder.sign(parent.key, algorithm=signature_hash(parent.key))
         else:
-            cert = builder.sign(key, algorithm=hashes.SHA256())
+            cert = builder.sign(key, algorithm=signature_hash(key))
 
         return CertificatePair(cert, key)
 
@@ -360,7 +378,7 @@ def leaf_cert(
 
         certificate = builder.sign(
             private_key=parent.key,
-            algorithm=hashes.SHA256(),
+            algorithm=signature_hash(parent.key),
         )
 
         return CertificatePair(certificate, key)
@@ -407,7 +425,7 @@ def crl(
 
         crl = builder.sign(
             private_key=key,
-            algorithm=hashes.SHA256(),
+            algorithm=signature_hash(key),
         )
 
         return crl

limbo/testcases/invalid.py

@@ -17,7 +17,7 @@ def sign(
         self,
         data: bytes,
         padding: AsymmetricPadding,
-        algorithm: asym_utils.Prehashed | hashes.HashAlgorithm,
+        algorithm: asym_utils.Prehashed | hashes.HashAlgorithm | asym_utils.NoDigestInfo,
     ) -> bytes:
         # SEQUENCE {}
         return b"\x30\x00"
@@ -46,6 +46,9 @@ def private_numbers(self) -> rsa.RSAPrivateNumbers:
     def __copy__(self) -> MalformedRSAPrivateKey:
         raise NotImplementedError
 
+    def __deepcopy__(self, memo: dict) -> MalformedRSAPrivateKey:
+        raise NotImplementedError
+
 
 class MalformedRSAPublicKey(rsa.RSAPublicKey):
     def public_bytes(
@@ -88,7 +91,7 @@ def recover_data_from_signature(
         self,
         signature: bytes,
         padding: AsymmetricPadding,
-        algorithm: hashes.HashAlgorithm | None,
+        algorithm: hashes.HashAlgorithm | asym_utils.NoDigestInfo | None,
     ) -> bytes:
         raise NotImplementedError
 
@@ -104,6 +107,9 @@ def verify(
     def __copy__(self) -> MalformedRSAPublicKey:
         raise NotImplementedError
 
+    def __deepcopy__(self, memo: dict) -> MalformedRSAPublicKey:
+        raise NotImplementedError
+
 
 @testcase
 def invalid_issuer_key(builder: Builder) -> None: