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,KeymasterKeyBlob * key_blob,AuthorizationSet * hw_enforced,AuthorizationSet * sw_enforced) const33 keymaster_error_t SymmetricKeyFactory::GenerateKey(const AuthorizationSet& key_description,
34 KeymasterKeyBlob* key_blob,
35 AuthorizationSet* hw_enforced,
36 AuthorizationSet* sw_enforced) const {
37 if (!key_blob || !hw_enforced || !sw_enforced)
38 return KM_ERROR_OUTPUT_PARAMETER_NULL;
39
40 uint32_t key_size_bits;
41 if (!key_description.GetTagValue(TAG_KEY_SIZE, &key_size_bits) ||
42 !key_size_supported(key_size_bits))
43 return KM_ERROR_UNSUPPORTED_KEY_SIZE;
44
45 keymaster_error_t error = validate_algorithm_specific_new_key_params(key_description);
46 if (error != KM_ERROR_OK)
47 return error;
48
49 size_t key_data_size = key_size_bytes(key_size_bits);
50 KeymasterKeyBlob key_material(key_data_size);
51 if (!key_material.key_material)
52 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,KeymasterKeyBlob * output_key_blob,AuthorizationSet * hw_enforced,AuthorizationSet * sw_enforced) 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 KeymasterKeyBlob* output_key_blob,
68 AuthorizationSet* hw_enforced,
69 AuthorizationSet* sw_enforced) const {
70 if (!output_key_blob || !hw_enforced || !sw_enforced)
71 return KM_ERROR_OUTPUT_PARAMETER_NULL;
72
73 AuthorizationSet authorizations(key_description);
74
75 uint32_t key_bits;
76 if (!authorizations.GetTagValue(TAG_KEY_SIZE, &key_bits)) {
77 // Determine key size if not provided.
78 key_bits = key_size_bits(input_key_material.key_material_size);
79 authorizations.push_back(TAG_KEY_SIZE, key_bits);
80 }
81
82 keymaster_error_t error = validate_algorithm_specific_new_key_params(key_description);
83 if (error != KM_ERROR_OK) return error;
84 if (!key_size_supported(key_bits)) return KM_ERROR_UNSUPPORTED_KEY_SIZE;
85 if (input_key_material_format != KM_KEY_FORMAT_RAW) return KM_ERROR_UNSUPPORTED_KEY_FORMAT;
86
87 if (key_bits != key_size_bits(input_key_material.key_material_size)) {
88 LOG_E("Expected %d-bit key data but got %d-bit key", key_bits,
89 key_size_bits(input_key_material.key_material_size));
90 return KM_ERROR_INVALID_KEY_BLOB;
91 }
92
93 return blob_maker_.CreateKeyBlob(authorizations, KM_ORIGIN_IMPORTED, input_key_material,
94 output_key_blob, hw_enforced, sw_enforced);
95 }
96
97 static const keymaster_key_format_t supported_import_formats[] = {KM_KEY_FORMAT_RAW};
98 const keymaster_key_format_t*
SupportedImportFormats(size_t * format_count) const99 SymmetricKeyFactory::SupportedImportFormats(size_t* format_count) const {
100 *format_count = array_length(supported_import_formats);
101 return supported_import_formats;
102 }
103
SymmetricKey(KeymasterKeyBlob && key_material,AuthorizationSet && hw_enforced,AuthorizationSet && sw_enforced,const KeyFactory * key_factory)104 SymmetricKey::SymmetricKey(KeymasterKeyBlob&& key_material,
105 AuthorizationSet&& hw_enforced, AuthorizationSet&& sw_enforced,
106 const KeyFactory* key_factory)
107 : Key(move(hw_enforced), move(sw_enforced), key_factory) {
108 key_material_ = move(key_material);
109 }
110
~SymmetricKey()111 SymmetricKey::~SymmetricKey() {}
112
113 } // namespace keymaster
114