New module for key material for asymmetric key types

Asymmetric keys can't just be arbitrary byte strings: the public key
has to match the private key and the private key usually has
nontrivial constraints.

In order to have deterministic test data and not to rely on
cryptographic dependencies in the Python script, hard-code some test
keys.

In this commit, copy some test keys from test_suite_psa_crypto.data.

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>

scripts/mbedtls_dev/asymmetric_key_data.py

@@ -0,0 +1,78 @@
+"""Sample key material for asymmetric key types.
+
+Meant for use in crypto_knowledge.py.
+"""
+
+# Copyright The Mbed TLS Contributors
+# SPDX-License-Identifier: Apache-2.0
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import binascii
+import re
+from typing import Dict
+
+STR_TRANS_REMOVE_BLANKS = str.maketrans('', '', ' \t\n\r')
+
+def unhexlify(text: str) -> bytes:
+    return binascii.unhexlify(text.translate(STR_TRANS_REMOVE_BLANKS))
+
+def construct_asymmetric_key_data(src) -> Dict[str, Dict[int, bytes]]:
+    """Split key pairs into separate table entries and convert hex to bytes.
+
+    Input format: src[abbreviated_type][size] = (private_key_hex, public_key_hex)
+    Output format: dst['PSA_KEY_TYPE_xxx'][size] = key_bytes
+    """
+    dst = {} #type: Dict[str, Dict[int, bytes]]
+    for typ in src:
+        private = 'PSA_KEY_TYPE_' + re.sub(r'(\(|\Z)', r'_KEY_PAIR\1', typ, 1)
+        public = 'PSA_KEY_TYPE_' + re.sub(r'(\(|\Z)', r'_PUBLIC_KEY\1', typ, 1)
+        dst[private] = {}
+        dst[public] = {}
+        for size in src[typ]:
+            dst[private][size] = unhexlify(src[typ][size][0])
+            dst[public][size] = unhexlify(src[typ][size][1])
+    return dst
+
+## These are valid keys that don't try to exercise any edge cases. They're
+## either test vectors from some specification, or randomly generated. All
+## pairs consist of a private key and its public key.
+#pylint: disable=line-too-long
+ASYMMETRIC_KEY_DATA = construct_asymmetric_key_data({
+    'ECC(PSA_ECC_FAMILY_SECP_R1)': {
+        256: ("49c9a8c18c4b885638c431cf1df1c994131609b580d4fd43a0cab17db2f13eee",
+              "047772656f814b399279d5e1f1781fac6f099a3c5ca1b0e35351834b08b65e0b572590cdaf8f769361bcf34acfc11e5e074e8426bdde04be6e653945449617de45"),
+        384: ("3f5d8d9be280b5696cc5cc9f94cf8af7e6b61dd6592b2ab2b3a4c607450417ec327dcdcaed7c10053d719a0574f0a76a",
+              "04d9c662b50ba29ca47990450e043aeaf4f0c69b15676d112f622a71c93059af999691c5680d2b44d111579db12f4a413a2ed5c45fcfb67b5b63e00b91ebe59d09a6b1ac2c0c4282aa12317ed5914f999bc488bb132e8342cc36f2ca5e3379c747"),
+        521: ("01b1b6ad07bb79e7320da59860ea28e055284f6058f279de666e06d435d2af7bda28d99fa47b7dd0963e16b0073078ee8b8a38d966a582f46d19ff95df3ad9685aae",
+              "04001de142d54f69eb038ee4b7af9d3ca07736fd9cf719eb354d69879ee7f3c136fb0fbf9f08f86be5fa128ec1a051d3e6c643e85ada8ffacf3663c260bd2c844b6f5600cee8e48a9e65d09cadd89f235dee05f3b8a646be715f1f67d5b434e0ff23a1fc07ef7740193e40eeff6f3bcdfd765aa9155033524fe4f205f5444e292c4c2f6ac1"),
+    },
+    'RSA': {
+        1024: ("""
+3082025e
+ 020100
+ 02818100af057d396ee84fb75fdbb5c2b13c7fe5a654aa8aa2470b541ee1feb0b12d25c79711531249e1129628042dbbb6c120d1443524ef4c0e6e1d8956eeb2077af12349ddeee54483bc06c2c61948cd02b202e796aebd94d3a7cbf859c2c1819c324cb82b9cd34ede263a2abffe4733f077869e8660f7d6834da53d690ef7985f6bc3
+ 0203010001
+ 02818100874bf0ffc2f2a71d14671ddd0171c954d7fdbf50281e4f6d99ea0e1ebcf82faa58e7b595ffb293d1abe17f110b37c48cc0f36c37e84d876621d327f64bbe08457d3ec4098ba2fa0a319fba411c2841ed7be83196a8cdf9daa5d00694bc335fc4c32217fe0488bce9cb7202e59468b1ead119000477db2ca797fac19eda3f58c1
+ 024100e2ab760841bb9d30a81d222de1eb7381d82214407f1b975cbbfe4e1a9467fd98adbd78f607836ca5be1928b9d160d97fd45c12d6b52e2c9871a174c66b488113
+ 024100c5ab27602159ae7d6f20c3c2ee851e46dc112e689e28d5fcbbf990a99ef8a90b8bb44fd36467e7fc1789ceb663abda338652c3c73f111774902e840565927091
+ 024100b6cdbd354f7df579a63b48b3643e353b84898777b48b15f94e0bfc0567a6ae5911d57ad6409cf7647bf96264e9bd87eb95e263b7110b9a1f9f94acced0fafa4d
+ 024071195eec37e8d257decfc672b07ae639f10cbb9b0c739d0c809968d644a94e3fd6ed9287077a14583f379058f76a8aecd43c62dc8c0f41766650d725275ac4a1
+ 024100bb32d133edc2e048d463388b7be9cb4be29f4b6250be603e70e3647501c97ddde20a4e71be95fd5e71784e25aca4baf25be5738aae59bbfe1c997781447a2b24
+""", """
+ 308189
+  02818100af057d396ee84fb75fdbb5c2b13c7fe5a654aa8aa2470b541ee1feb0b12d25c79711531249e1129628042dbbb6c120d1443524ef4c0e6e1d8956eeb2077af12349ddeee54483bc06c2c61948cd02b202e796aebd94d3a7cbf859c2c1819c324cb82b9cd34ede263a2abffe4733f077869e8660f7d6834da53d690ef7985f6bc3
+ 0203010001
+"""),
+    },
+})

scripts/mbedtls_dev/crypto_knowledge.py

@@ -21,6 +21,8 @@ This module is entirely based on the PSA API.
 import re
 from typing import List, Optional, Tuple
 
+from mbedtls_dev.asymmetric_key_data import ASYMMETRIC_KEY_DATA
+
 class KeyType:
     """Knowledge about a PSA key type."""
 
@@ -101,13 +103,18 @@ class KeyType:
         psa_export_key(id, `material`, ...);
         ```
         """
+        if self.expression in ASYMMETRIC_KEY_DATA:
+            if bits not in ASYMMETRIC_KEY_DATA[self.expression]:
+                raise ValueError('No key data for {}-bit {}'
+                                 .format(bits, self.expression))
+            return ASYMMETRIC_KEY_DATA[self.expression][bits]
         if bits % 8 != 0:
-            raise ValueError('Non-integer number of bytes: {} bits'.format(bits))
+            raise ValueError('Non-integer number of bytes: {} bits for {}'
+                             .format(bits, self.expression))
         length = bits // 8
         if self.name == 'PSA_KEY_TYPE_DES':
             # "644573206b457901644573206b457902644573206b457904"
             des3 = b'dEs kEy\001dEs kEy\002dEs kEy\004'
             return des3[:length]
-        # TODO: ECC, RSA
         return b''.join([self.DATA_BLOCK] * (length // len(self.DATA_BLOCK)) +
                         [self.DATA_BLOCK[:length % len(self.DATA_BLOCK)]])