#!/usr/bin/env python # Test of key backup code, will evolve into unit tests and a user # backup script after initial debugging. # KEY SOURCE KEY BACKUP # # Generate and export KEKEK: # hal_rpc_pkey_generate_rsa() # hal_rpc_pkey_get_public_key() # # Load KEKEK public <---------------- Export KEKEK public # # { # "kekek-uuid": "[UUID]", # "kekek": "[Base64]" # } # # hal_rpc_pkey_load() # hal_rpc_pkey_export() # # Export PKCS #8 and KEK ----------> Load PKCS #8 and KEK, import key: # # { # "kekek-uuid": "[UUID]", # "pkey": "[Base64]", # "kek": "[Base64]" # } # # # hal_rpc_pkey_import() from libhal import * from Crypto.PublicKey import RSA from Crypto.Cipher import AES, PKCS1_v1_5 from Crypto.Util.asn1 import DerObject, DerSequence, DerNull, DerOctetString, DerObjectId from Crypto.Random import new as csprng from struct import pack, unpack def dumpasn1(der): from subprocess import call from tempfile import NamedTemporaryFile with NamedTemporaryFile() as f: f.write(der) f.flush() call(("dumpasn1", "-aop", f.name)) def t(x): return filter(x.isType, x.typeTags)[0] hal_asn1_oid_rsaEncryption = "\x2A\x86\x48\x86\xF7\x0D\x01\x01\x01" hal_asn1_oid_aesKeyWrap = "\x60\x86\x48\x01\x65\x03\x04\x01\x30" kek_length = 256/8 # We can determine this from the keywrap OID, this is for AES-256 def main(): kekek = RSA.importKey(kekek_pem) from atexit import register as atexit hsm = HSM() #hsm.debug_io = args.io_log hsm.login(HAL_USER_WHEEL, "fnord") atexit(hsm.logout) kekek_handle = hsm.pkey_load(type = HAL_KEY_TYPE_RSA_PUBLIC, curve = HAL_CURVE_NONE, der = kekek.publickey().exportKey(format = "DER")) atexit(kekek_handle.delete) print "KEKEK:", kekek_handle.uuid pkey_handle = hsm.pkey_generate_ec(HAL_CURVE_P256, HAL_KEY_FLAG_EXPORTABLE) atexit(pkey_handle.delete) print "PKey: ", pkey_handle.uuid pkcs8_der, kek_der = kekek_handle.export_pkey(pkey_handle) pkcs8_alg, pkcs8_data = show_encrypted_pkcs8("PKCS #8:", pkcs8_der, hal_asn1_oid_aesKeyWrap) kek_alg, kek_data = show_encrypted_pkcs8("KEK: ", kek_der, hal_asn1_oid_rsaEncryption) # Voodoo to defend against Bleichenbacher Attack per Crypto.Cipher.PKCS1_v1_5 API documentation kek = PKCS1_v1_5.new(kekek).decrypt(kek_data, csprng().read(kek_length)) pkey = AESKeyWrapWithPadding(kek).unwrap(pkcs8_data) dumpasn1(pkey) def show_encrypted_pkcs8(label, der, oid): print print label dumpasn1(der) print result = parse_encrypted_pkcs8(der) for name, value in zip(("algorithm", "encryptedData"), result): print "{:14s} {}".format(name, "-".join("{:02x}".format(ord(v)) for v in value)) print print "OID {}".format("matches" if result[0] == oid else "doesn't match") return result def parse_encrypted_pkcs8(der): encryptedPrivateKeyInfo = DerSequence() encryptedPrivateKeyInfo.decode(der) encryptionAlgorithm = DerSequence() encryptionAlgorithm.decode(encryptedPrivateKeyInfo[0]) algorithm = DerObjectId() algorithm.decode(encryptionAlgorithm[0]) encryptedData = DerObject() encryptedData.decode(encryptedPrivateKeyInfo[1]) return algorithm.payload, encryptedData.payload class AESKeyWrapWithPadding(object): """ Implementation of AES Key Wrap With Padding from RFC 5649. """ class UnwrapError(Exception): "Something went wrong during unwrap." def __init__(self, key): self.ctx = AES.new(key, AES.MODE_ECB) def _encrypt(self, b1, b2): aes_block = self.ctx.encrypt(b1 + b2) return aes_block[:8], aes_block[8:] def _decrypt(self, b1, b2): aes_block = self.ctx.decrypt(b1 + b2) return aes_block[:8], aes_block[8:] @staticmethod def _start_stop(start, stop): # Syntactic sugar step = -1 if start > stop else 1 return xrange(start, stop + step, step) def wrap(self, Q): "RFC 5649 section 4.1." m = len(Q) # Plaintext length if m % 8 != 0: # Pad Q if needed Q += "\x00" * (8 - (m % 8)) R = [pack(">LL", 0xa65959a6, m)] # Magic MSB(32,A), build LSB(32,A) R.extend(Q[i : i + 8] # Append Q for i in xrange(0, len(Q), 8)) n = len(R) - 1 if n == 1: R[0], R[1] = self._encrypt(R[0], R[1]) else: # RFC 3394 section 2.2.1 for j in self._start_stop(0, 5): for i in self._start_stop(1, n): R[0], R[i] = self._encrypt(R[0], R[i]) W0, W1 = unpack(">LL", R[0]) W1 ^= n * j + i R[0] = pack(">LL", W0, W1) assert len(R) == (n + 1) and all(len(r) == 8 for r in R) return "".join(R) def unwrap(self, C): "RFC 5649 section 4.2." if len(C) % 8 != 0: raise self.UnwrapError("Ciphertext length {} is not an integral number of blocks" .format(len(C))) n = (len(C) / 8) - 1 R = [C[i : i + 8] for i in xrange(0, len(C), 8)] if n == 1: R[0], R[1] = self._decrypt(R[0], R[1]) else: # RFC 3394 section 2.2.2 steps (1), (2), and part of (3) for j in self._start_stop(5, 0): for i in self._start_stop(n, 1): W0, W1 = unpack(">LL", R[0]) W1 ^= n * j + i R[0] = pack(">LL", W0, W1) R[0], R[i] = self._decrypt(R[0], R[i]) magic, m = unpack(">LL", R[0]) if magic != 0xa65959a6: raise self.UnwrapError("Magic value in AIV should have been 0xa65959a6, was 0x{:02x}" .format(magic)) if m <= 8 * (n - 1) or m > 8 * n: raise self.UnwrapError("Length encoded in AIV out of range: m {}, n {}".format(m, n)) R = "".join(R[1:]) assert len(R) == 8 * n if any(r != "\x00" for r in R[m:]): raise self.UnwrapError("Nonzero trailing bytes {}".format(R[m:].encode("hex"))) return R[:m] # Static KEKEK for testing, this should come from the backup HSM. kekek_pem = '''\ -----BEGIN PRIVATE KEY----- MIIEvwIBADANBgkqhkiG9w0BAQEFAASCBKkwggSlAgEAAoIBAQDTtBJvz+55FBHH 0NhDZ6Xdp07kUPFxn9lYlNwg5BmSBPbXT/2JindI9NrfEx4xX0i0d3OxnbQoc8RJ WsF2ujALBAU92yO9bjbxUbgxvecy3by/UNulLo9pOhKD2hgCkH6FWdlE7wbIfex1 pIFL1ms/h6qBme8qvXEGqTh79S5krVQG/tVZFyNyVanzrVCcAVGhZ/RqXK4Lb7pF QJg1tNuYaQkNieiVPpoxuqAX0jP0iot2OXwlMUj2aHl/cQfdmIYKCmC3IQfuCy1m grdW7Sb2u87tH6aFSEp4mCbScXYac7lBsi4AOQQcGR8816NslDqYU/0+cYcU4Ub/ 0D8W2Nr9AgMBAAECggEBAIIJ2klUL+evrDxQzIaa5AeC/bLBBY4F4jvHNG//rLVE 11rqh5I0u5DU1pyv4ZvyK3au6SHw/PjcI3XriWqkc15Q2edk9E8npBgXWk0zmRBl o8rgoAqWzwCT60uSa60nlI/U4OC28jO1Jcodgk5TJw2fB90T8RUPyJ2O1GNP929e 6autPcifNNBQGNAiVCMAboNHOunr0fBO28JAcEhgw5CqpjCNbWbv9YLPAaIB6Fr9 mnidOB7UNQ8Uk+bybuSz7DtsmOpbktjBcbgQVpqJyzkjsA/2LjoTavUTq2UALtk2 VeNVebfvQq7crMsfV09r0EdrAx3wawjrX/jyrbwf8AECgYEA+yfx0Fg5Kn+7ierT nLbJ1HgIra8KabmJB629cXjhllO1gBH7NdFU/13H9dPhcehA0zYkZuvQOWWRjh28 VJhwb4fSdtlkxukqJfNNrppYhEmr3zs6RFJYb3qZKZSZE7Bo1S6WeM1cMQWY94le GylVC5f52a6H199hHiKQ9pIjKK0CgYEA18lVm6f1L/8wC3rXB7PW628ImQoIOFaT mAdBtfGgUfpVk8xsuipJ4bqve45l6B8s49xr3rY/j4t8wETE11h4kLaQGicRVXFq 7xJUR4xZYYnDKMC2LwSHbd0JxYekKa4uaC9Sd6g5Pyg1f8QVmXdShI0z0Hpr3aYY hdXNfFDvNZECgYEAp1/wY9NXjX4AYiIPkiGykZjI186OFvUhX++mD2fqln8EtuvE yRHPHjvGVYo1dO69vMQZMEm4w3dvsBEbABly3LDcTn4EDhc3EoF5ZIHRuZ9LHgJf i0aBTxGZ3r774MYwptlcR/c7mCPN1DFEeL9rwMUwKaSJPRDNrQKGLvwm2CUCgYBK LBN4GKiH4gCiwYuuQxvp+1WKPU+MBf5fsIbewnpoE1NdJVRuPWD97UyqfMz8l9K3 VCnj+OMqNTkhYcIDf46Zt5ca1jj4FK88FCHSIiULCO6DUJKO4NCoa+US98fu58dd 2n5PUQy0b97L1xvRj5lWpK6dx6bSHmipgE9MnwlKcQKBgQCZR2Czs0O/fi1V0Ecl d1XDDCAS3sECclhqiJkcn9TaM/0chGR7E//0ChP82ca5ihkByVgsOfaYaWZg+Eci FUQep3DnjONc0kX9xeiSn3Z2jbUMcoub/uY0OWreE+3FL1ZgjYs1KKdUOWF2DL/X L7en4sepnWifRGs2gnPYKrn1Zg== -----END PRIVATE KEY----- ''' if __name__ == "__main__": main()