1 /*
2 * Copyright 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include <keymaster/km_openssl/symmetric_key.h>
18
19 #include <assert.h>
20
21 #include <openssl/err.h>
22 #include <openssl/rand.h>
23
24 #include <keymaster/android_keymaster_utils.h>
25 #include <keymaster/keymaster_context.h>
26 #include <keymaster/km_openssl/aes_key.h>
27 #include <keymaster/km_openssl/hmac_key.h>
28 #include <keymaster/km_openssl/openssl_err.h>
29 #include <keymaster/logger.h>
30
31 namespace keymaster {
32
GenerateKey(const AuthorizationSet & key_description,UniquePtr<Key>,const KeymasterBlob &,KeymasterKeyBlob * key_blob,AuthorizationSet * hw_enforced,AuthorizationSet * sw_enforced,CertificateChain *) const33 keymaster_error_t SymmetricKeyFactory::GenerateKey(const AuthorizationSet& key_description,
34 UniquePtr<Key> /* attest_key */,
35 const KeymasterBlob& /* issuer_subject */,
36 KeymasterKeyBlob* key_blob,
37 AuthorizationSet* hw_enforced,
38 AuthorizationSet* sw_enforced,
39 CertificateChain* /* cert_chain */) const {
40 if (!key_blob || !hw_enforced || !sw_enforced) return KM_ERROR_OUTPUT_PARAMETER_NULL;
41
42 uint32_t key_size_bits;
43 if (!key_description.GetTagValue(TAG_KEY_SIZE, &key_size_bits) ||
44 !key_size_supported(key_size_bits))
45 return KM_ERROR_UNSUPPORTED_KEY_SIZE;
46
47 keymaster_error_t error = validate_algorithm_specific_new_key_params(key_description);
48 if (error != KM_ERROR_OK) return error;
49
50 size_t key_data_size = key_size_bytes(key_size_bits);
51 KeymasterKeyBlob key_material(key_data_size);
52 if (!key_material.key_material) return KM_ERROR_MEMORY_ALLOCATION_FAILED;
53
54 error = random_source_.GenerateRandom(key_material.writable_data(), key_data_size);
55 if (error != KM_ERROR_OK) {
56 LOG_E("Error generating %d bit symmetric key", key_size_bits);
57 return error;
58 }
59
60 return blob_maker_.CreateKeyBlob(key_description, KM_ORIGIN_GENERATED, key_material, key_blob,
61 hw_enforced, sw_enforced);
62 }
63
ImportKey(const AuthorizationSet & key_description,keymaster_key_format_t input_key_material_format,const KeymasterKeyBlob & input_key_material,UniquePtr<Key>,const KeymasterBlob &,KeymasterKeyBlob * output_key_blob,AuthorizationSet * hw_enforced,AuthorizationSet * sw_enforced,CertificateChain *) const64 keymaster_error_t SymmetricKeyFactory::ImportKey(const AuthorizationSet& key_description, //
65 keymaster_key_format_t input_key_material_format,
66 const KeymasterKeyBlob& input_key_material, //
67 UniquePtr<Key> /* attest_key */,
68 const KeymasterBlob& /* issuer_subject */,
69 KeymasterKeyBlob* output_key_blob,
70 AuthorizationSet* hw_enforced,
71 AuthorizationSet* sw_enforced,
72 CertificateChain* /* cert_chain */) const {
73 if (!output_key_blob || !hw_enforced || !sw_enforced) return KM_ERROR_OUTPUT_PARAMETER_NULL;
74
75 AuthorizationSet authorizations(key_description);
76
77 uint32_t key_bits;
78 if (!authorizations.GetTagValue(TAG_KEY_SIZE, &key_bits)) {
79 // Determine key size if not provided.
80 key_bits = key_size_bits(input_key_material.key_material_size);
81 authorizations.push_back(TAG_KEY_SIZE, key_bits);
82 }
83
84 keymaster_error_t error = validate_algorithm_specific_new_key_params(key_description);
85 if (error != KM_ERROR_OK) return error;
86 if (!key_size_supported(key_bits)) return KM_ERROR_UNSUPPORTED_KEY_SIZE;
87 if (input_key_material_format != KM_KEY_FORMAT_RAW) return KM_ERROR_UNSUPPORTED_KEY_FORMAT;
88
89 if (key_bits != key_size_bits(input_key_material.key_material_size)) {
90 LOG_E("Expected %d-bit key data but got %d-bit key", key_bits,
91 key_size_bits(input_key_material.key_material_size));
92 return KM_ERROR_INVALID_KEY_BLOB;
93 }
94
95 return blob_maker_.CreateKeyBlob(authorizations, KM_ORIGIN_IMPORTED, input_key_material,
96 output_key_blob, hw_enforced, sw_enforced);
97 }
98
99 static const keymaster_key_format_t supported_import_formats[] = {KM_KEY_FORMAT_RAW};
100 const keymaster_key_format_t*
SupportedImportFormats(size_t * format_count) const101 SymmetricKeyFactory::SupportedImportFormats(size_t* format_count) const {
102 *format_count = array_length(supported_import_formats);
103 return supported_import_formats;
104 }
105
SymmetricKey(KeymasterKeyBlob && key_material,AuthorizationSet && hw_enforced,AuthorizationSet && sw_enforced,const KeyFactory * key_factory)106 SymmetricKey::SymmetricKey(KeymasterKeyBlob&& key_material, AuthorizationSet&& hw_enforced,
107 AuthorizationSet&& sw_enforced, const KeyFactory* key_factory)
108 : Key(move(hw_enforced), move(sw_enforced), key_factory) {
109 key_material_ = move(key_material);
110 }
111
~SymmetricKey()112 SymmetricKey::~SymmetricKey() {}
113
114 } // namespace keymaster
115