New version of signing script and signing process

Ref: NCSDK-31069

Signed-off-by: Artur Hadasz <[email protected]>

ncs/Kconfig

@@ -105,4 +105,70 @@ config SUIT_ENVELOPE_TARGET_ENCRYPT_PLAINTEXT_HASH_ALG_NAME
 	default "shake128" if SUIT_ENVELOPE_TARGET_ENCRYPT_PLAINTEXT_HASH_ALG_SHAKE128
 	default "shake256" if SUIT_ENVELOPE_TARGET_ENCRYPT_PLAINTEXT_HASH_ALG_SHAKE256
 
-endif # SUIT_ENVELOPE_TARGET_ENCRYPT
+endif # SUIT_ENVELOPE_TARGET_ENCRYPT
+
+config SUIT_ENVELOPE_TARGET_SIGN
+	bool "Sign the target envelope"
+
+if SUIT_ENVELOPE_TARGET_SIGN
+
+choice SUIT_ENVELOPE_TARGET_SIGN_KEY_GEN
+	prompt "SUIT envelope signing key generation"
+	default SUIT_ENVELOPE_TARGET_SIGN_KEY_GEN1
+
+	config SUIT_ENVELOPE_TARGET_SIGN_KEY_GEN1
+		bool "Key generation 1"
+
+	config SUIT_ENVELOPE_TARGET_SIGN_KEY_GEN2
+		bool "Key generation 2"
+
+	config SUIT_ENVELOPE_TARGET_SIGN_KEY_GEN3
+		bool "Key generation 3"
+endchoice
+
+config SUIT_ENVELOPE_TARGET_SIGN_KEY_ID
+	hex "The key ID used to identify the public key on the device"
+	default 0x40022100 if SOC_NRF54H20_CPUAPP_COMMON && SUIT_ENVELOPE_TARGET_SIGN_KEY_GEN1
+	default 0x40022101 if SOC_NRF54H20_CPUAPP_COMMON && SUIT_ENVELOPE_TARGET_SIGN_KEY_GEN2
+	default 0x40022102 if SOC_NRF54H20_CPUAPP_COMMON && SUIT_ENVELOPE_TARGET_SIGN_KEY_GEN3
+	default 0x40032100 if SOC_NRF54H20_CPURAD_COMMON && SUIT_ENVELOPE_TARGET_SIGN_KEY_GEN1
+	default 0x40032101 if SOC_NRF54H20_CPURAD_COMMON && SUIT_ENVELOPE_TARGET_SIGN_KEY_GEN2
+	default 0x40032102 if SOC_NRF54H20_CPURAD_COMMON && SUIT_ENVELOPE_TARGET_SIGN_KEY_GEN3
+	help
+	  This string is translated to the numeric KEY ID by the encryption script
+
+config SUIT_ENVELOPE_TARGET_SIGN_PRIVATE_KEY_NAME
+	string "Name of the private key used for signing - to identify the key in the KMS"
+	default "MANIFEST_APPLICATION_GEN1_priv" if SOC_NRF54H20_CPUAPP_COMMON && SUIT_ENVELOPE_TARGET_SIGN_KEY_GEN1
+	default "MANIFEST_APPLICATION_GEN2_priv" if SOC_NRF54H20_CPUAPP_COMMON && SUIT_ENVELOPE_TARGET_SIGN_KEY_GEN2
+	default "MANIFEST_APPLICATION_GEN3_priv" if SOC_NRF54H20_CPUAPP_COMMON && SUIT_ENVELOPE_TARGET_SIGN_KEY_GEN3
+	default "MANIFEST_RADIOCORE_GEN1_priv" if SOC_NRF54H20_CPURAD_COMMON && SUIT_ENVELOPE_TARGET_SIGN_KEY_GEN1
+	default "MANIFEST_RADIOCORE_GEN2_priv" if SOC_NRF54H20_CPURAD_COMMON && SUIT_ENVELOPE_TARGET_SIGN_KEY_GEN2
+	default "MANIFEST_RADIOCORE_GEN3_priv" if SOC_NRF54H20_CPURAD_COMMON && SUIT_ENVELOPE_TARGET_SIGN_KEY_GEN3
+
+choice SUIT_ENVELOPE_TARGET_SIGN_ALG
+	prompt "Algorithm used to sign the target envelope"
+	default SUIT_ENVELOPE_TARGET_SIGN_ALG_EDDSA
+
+config SUIT_ENVELOPE_TARGET_SIGN_ALG_EDDSA
+	bool "Use the EdDSA algorithm"
+
+config SUIT_ENVELOPE_TARGET_SIGN_ALG_ECDSA_256
+	bool "Use the ECDSA algorithm with key length of 256 bits"
+
+config SUIT_ENVELOPE_TARGET_SIGN_ALG_ECDSA_384
+	bool "Use the ECDSA algorithm with key length of 384 bits"
+
+config SUIT_ENVELOPE_TARGET_SIGN_ALG_ECDSA_521
+	bool "Use the ECDSA algorithm with key length of 521 bits"
+
+endchoice
+
+config SUIT_ENVELOPE_TARGET_SIGN_ALG_NAME
+	string "String name of the algorithm used to sign the target envelope"
+	default "eddsa" if SUIT_ENVELOPE_TARGET_SIGN_ALG_EDDSA
+	default "es-256" if SUIT_ENVELOPE_TARGET_SIGN_ALG_ECDSA_256
+	default "es-384" if SUIT_ENVELOPE_TARGET_SIGN_ALG_ECDSA_384
+	default "es-521" if SUIT_ENVELOPE_TARGET_SIGN_ALG_ECDSA_521
+
+endif # SUIT_ENVELOPE_TARGET_SIGN

ncs/basic_kms.py

@@ -9,6 +9,16 @@
 
 from pathlib import Path
 from cryptography.hazmat.primitives.ciphers.aead import AESGCM
+
+from cryptography.hazmat.primitives.serialization import load_pem_private_key, load_der_private_key
+from cryptography.hazmat.primitives.asymmetric.ec import EllipticCurvePrivateKey
+from cryptography.hazmat.primitives.asymmetric.ed25519 import Ed25519PrivateKey
+from cryptography.hazmat.primitives.asymmetric.ed448 import Ed448PrivateKey
+from cryptography.hazmat.primitives.asymmetric import ec
+from cryptography.hazmat.primitives import hashes
+from cryptography.hazmat.primitives.asymmetric.utils import decode_dss_signature
+import math
+
 from suit_generator.suit_kms_base import SuitKMSBase
 import json
 
@@ -72,6 +82,73 @@ def encrypt(self, plaintext, key_name, context, aad) -> tuple[bytes, bytes, byte
 
         return nonce, tag, ciphertext
 
+    def _verify_signing_key_type(self, private_key, algorithm) -> bool:
+        """Verify if the key type matches the provided key."""
+        if isinstance(private_key, EllipticCurvePrivateKey):
+            return f"es-{private_key.key_size}" == algorithm
+        elif isinstance(private_key, Ed25519PrivateKey) or isinstance(private_key, Ed448PrivateKey):
+            return "eddsa" == algorithm
+        else:
+            raise ValueError(f"Key {type(private_key)} not supported")
+
+    def _create_cose_es_signature(self, input_data, private_key: bytes) -> bytes:
+        """Create ECDSA signature and return signature bytes."""
+        hash_map = {256: hashes.SHA256(), 384: hashes.SHA384(), 521: hashes.SHA512()}
+        dss_signature = private_key.sign(input_data, ec.ECDSA(hash_map[private_key.key_size]))
+        r, s = decode_dss_signature(dss_signature)
+        return r.to_bytes(math.ceil(private_key.key_size / 8), byteorder="big") + s.to_bytes(
+            math.ceil(private_key.key_size / 8), byteorder="big"
+        )
+
+    def _create_cose_ed_signature(self, input_data, private_key: bytes) -> bytes:
+        """Create ECDSA signature and return signature bytes."""
+        return private_key.sign(input_data)
+
+    def _get_sign_method(self, private_key) -> bool:
+        """Return sign method based on key type."""
+        if isinstance(private_key, EllipticCurvePrivateKey):
+            return self._create_cose_es_signature
+        elif isinstance(private_key, Ed25519PrivateKey) or isinstance(private_key, Ed448PrivateKey):
+            return self._create_cose_ed_signature
+        else:
+            raise ValueError(f"Key {type(private_key)} not supported")
+
+    def sign(self, data, key_name, algorithm, context) -> bytes:
+        """
+        Sign the data with a private key.
+
+        :param data: The data to be signed.
+        :param key_name: The name of the private key to be used.
+        :param algorithm: The name of the algorithm to be used.
+                          Used to verify if the key in the provided file contains a key of a compatible type.
+        :param context: The context to be used
+
+        :return: The signature.
+        :rtype: bytes
+        """
+        # TODO: support DER format
+        key_file_name = key_name + ".pem"
+        private_key_path = self.keys_directory / key_file_name
+        loaders = {
+            ".pem": load_pem_private_key,
+            ".der": load_der_private_key,
+        }
+
+        try:
+            loader = loaders[private_key_path.suffix]
+        except KeyError as e:
+            raise ValueError("Unrecognized private key format. Extension must be {per,der}") from e
+        with open(private_key_path, "rb") as private_key:
+            private_key = loader(private_key.read(), None)
+
+        if not self._verify_signing_key_type(private_key, algorithm):
+            raise ValueError(f"Key {key_file_name} is not compatible with algorithm {algorithm}")
+
+        sign_method = self._get_sign_method(private_key)
+        signature = sign_method(data, private_key)
+
+        return signature
+
 
 def suit_kms_factory():
     """Get a KMS object."""

ncs/encrypt_script.py

@@ -132,6 +132,8 @@ def init_kms_backend(self, kms_script, context):
         """Initialize the KMS from the provided script backend based on the passed context."""
         module_name = "SuitKMS_module"
         kms_module = _import_module_from_path(module_name, kms_script)
+        if not hasattr(kms_module, "suit_kms_factory"):
+            raise ValueError(f"Python script {kms_script} does not contain the required suit_kms_factory function")
         self.kms = kms_module.suit_kms_factory()
         if not isinstance(self.kms, SuitKMSBase):
             raise ValueError(f"Class {type(self.kms)} does not implement the required SuitKMSBase interface")

ncs/sample_recursive_sign_config.json

@@ -0,0 +1,20 @@
+{
+    "key-name": "MANIFEST_OEM_ROOT_GEN1_priv",
+    "key-id": "0x4000AA00",
+    "alg": "eddsa",
+    "context": "<CONTEXT (by default path to key directory)>",
+    "sign-script": "<SIGN_SCRIPT path>",
+    "kms-script": "<KMS_SCRIPT path>",
+    "omit-signing": false,
+    "already-signed-action": "error",
+    "dependencies" : {
+        "#radio" : {
+            "key-name": "MANIFEST_RADIOCORE_GEN1_priv",
+	        "key-id": "0x40032100"
+        },
+        "#application" : {
+            "key-name": "MANIFEST_APPLICATION_GEN1_priv",
+	        "key-id": "0x40022100"
+        }
+    }
+}