SECENG-13957: fix: add ML-DSA support to bundler, initca renewal, and display functions

- bundler: accept ML-DSA certs in Bundle() key validation (key-present
  and keyless paths), add MLDSA key type and PKCS#8 serialization to
  MarshalJSON
- initca: add ML-DSA case to RenewFromSigner() key matching
- helpers: KeyLength() returns public key byte size (1312/1952/2592)
  per PQC func spec; SignatureString() and HashAlgoString() return
  MLDSA44/65/87 instead of "Unknown"

Author: ang-cloudflare

bundler/bundle.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"crypto/ecdsa"
 	"crypto/ed25519"
+	"crypto/mldsa"
 	"crypto/rsa"
 	"crypto/x509"
 	"crypto/x509/pkix"
@@ -112,6 +113,8 @@ func (b *Bundle) MarshalJSON() ([]byte, error) {
 		keyType = "DSA"
 	case x509.Ed25519:
 		keyType = "Ed25519"
+	case x509.MLDSA:
+		keyType = fmt.Sprintf("%d-byte ML-DSA", keyLength)
 	default:
 		keyType = "Unknown"
 	}
@@ -126,6 +129,9 @@ func (b *Bundle) MarshalJSON() ([]byte, error) {
 	case ed25519.PrivateKey:
 		keyBytes, _ = derhelpers.MarshalEd25519PrivateKey(key)
 		keyString = PemBlockToString(&pem.Block{Type: "Ed25519 PRIVATE KEY", Bytes: keyBytes})
+	case *mldsa.PrivateKey:
+		keyBytes, _ = x509.MarshalPKCS8PrivateKey(key)
+		keyString = PemBlockToString(&pem.Block{Type: "PRIVATE KEY", Bytes: keyBytes})
 	case fmt.Stringer:
 		keyString = key.String()
 	}

bundler/bundler.go

@@ -7,6 +7,7 @@ import (
 	"crypto"
 	"crypto/ecdsa"
 	"crypto/ed25519"
+	"crypto/mldsa"
 	"crypto/rsa"
 	"crypto/tls"
 	"crypto/x509"
@@ -597,6 +598,14 @@ func (b *Bundler) Bundle(certs []*x509.Certificate, key crypto.Signer, flavor Bu
 			if !(bytes.Equal(cert.PublicKey.(ed25519.PublicKey), ed25519PublicKey)) {
 				return nil, errors.New(errors.PrivateKeyError, errors.KeyMismatch)
 			}
+		case cert.PublicKeyAlgorithm == x509.MLDSA:
+			var mldsaPublicKey *mldsa.PublicKey
+			if mldsaPublicKey, ok = key.Public().(*mldsa.PublicKey); !ok {
+				return nil, errors.New(errors.PrivateKeyError, errors.KeyMismatch)
+			}
+			if !cert.PublicKey.(*mldsa.PublicKey).Equal(mldsaPublicKey) {
+				return nil, errors.New(errors.PrivateKeyError, errors.KeyMismatch)
+			}
 		default:
 			return nil, errors.New(errors.PrivateKeyError, errors.NotRSAOrECCOrEd25519)
 		}
@@ -605,6 +614,7 @@ func (b *Bundler) Bundle(certs []*x509.Certificate, key crypto.Signer, flavor Bu
 		case cert.PublicKeyAlgorithm == x509.RSA:
 		case cert.PublicKeyAlgorithm == x509.ECDSA:
 		case cert.PublicKeyAlgorithm == x509.Ed25519:
+		case cert.PublicKeyAlgorithm == x509.MLDSA:
 		default:
 			return nil, errors.New(errors.PrivateKeyError, errors.NotRSAOrECCOrEd25519)
 		}

helpers/helpers.go

@@ -74,6 +74,15 @@ func KeyLength(key interface{}) int {
 		return rsaKey.N.BitLen()
 	} else if _, ok := key.(ed25519.PublicKey); ok {
 		return ed25519.PublicKeySize
+	} else if mldsaKey, ok := key.(*mldsa.PublicKey); ok {
+		switch {
+		case mldsaKey.Parameters() == mldsa.MLDSA44():
+			return 1312
+		case mldsaKey.Parameters() == mldsa.MLDSA65():
+			return 1952
+		case mldsaKey.Parameters() == mldsa.MLDSA87():
+			return 2592
+		}
 	}
 
 	return 0
@@ -157,6 +166,12 @@ func SignatureString(alg x509.SignatureAlgorithm) string {
 		return "ECDSAWithSHA512"
 	case x509.PureEd25519:
 		return "Ed25519"
+	case x509.MLDSA44:
+		return "MLDSA44"
+	case x509.MLDSA65:
+		return "MLDSA65"
+	case x509.MLDSA87:
+		return "MLDSA87"
 	default:
 		return "Unknown Signature"
 	}
@@ -192,6 +207,12 @@ func HashAlgoString(alg x509.SignatureAlgorithm) string {
 		return "SHA512"
 	case x509.PureEd25519:
 		return "Ed25519"
+	case x509.MLDSA44:
+		return "MLDSA44"
+	case x509.MLDSA65:
+		return "MLDSA65"
+	case x509.MLDSA87:
+		return "MLDSA87"
 	default:
 		return "Unknown Hash Algorithm"
 	}

initca/initca.go

@@ -7,6 +7,7 @@ import (
 	"crypto"
 	"crypto/ecdsa"
 	"crypto/ed25519"
+	"crypto/mldsa"
 	"crypto/rand"
 	"crypto/rsa"
 	"crypto/x509"
@@ -220,6 +221,15 @@ func RenewFromSigner(ca *x509.Certificate, priv crypto.Signer) ([]byte, error) {
 		if !(bytes.Equal(ca.PublicKey.(ed25519.PublicKey), ed25519PublicKey)) {
 			return nil, cferr.New(cferr.PrivateKeyError, cferr.KeyMismatch)
 		}
+	case ca.PublicKeyAlgorithm == x509.MLDSA:
+		var mldsaPublicKey *mldsa.PublicKey
+		var ok bool
+		if mldsaPublicKey, ok = priv.Public().(*mldsa.PublicKey); !ok {
+			return nil, cferr.New(cferr.PrivateKeyError, cferr.KeyMismatch)
+		}
+		if !ca.PublicKey.(*mldsa.PublicKey).Equal(mldsaPublicKey) {
+			return nil, cferr.New(cferr.PrivateKeyError, cferr.KeyMismatch)
+		}
 	default:
 		return nil, cferr.New(cferr.PrivateKeyError, cferr.NotRSAOrECCOrEd25519)
 	}