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 33 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 64 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* 101 SymmetricKeyFactory::SupportedImportFormats(size_t* format_count) const { 102 *format_count = array_length(supported_import_formats); 103 return supported_import_formats; 104 } 105 106 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 } 111 112 SymmetricKey::~SymmetricKey() {} 113 114 } // namespace keymaster 115