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 "aes_operation.h" 18 19 namespace keymaster { 20 21 static const keymaster_block_mode_t supported_block_modes[] = {KM_MODE_ECB, KM_MODE_CBC, 22 KM_MODE_CTR, KM_MODE_GCM}; 23 24 const keymaster_block_mode_t* 25 AesEvpCipherDescription::SupportedBlockModes(size_t* block_mode_count) const { 26 *block_mode_count = array_length(supported_block_modes); 27 return supported_block_modes; 28 } 29 30 const EVP_CIPHER* AesEvpCipherDescription::GetCipherInstance(size_t key_size, 31 keymaster_block_mode_t block_mode, 32 keymaster_error_t* error) const { 33 *error = KM_ERROR_OK; 34 35 switch (block_mode) { 36 case KM_MODE_ECB: 37 switch (key_size) { 38 case 16: 39 return EVP_aes_128_ecb(); 40 case 24: 41 return EVP_aes_192_ecb(); 42 case 32: 43 return EVP_aes_256_ecb(); 44 }; 45 *error = KM_ERROR_UNSUPPORTED_KEY_SIZE; 46 break; 47 48 case KM_MODE_CBC: 49 switch (key_size) { 50 case 16: 51 return EVP_aes_128_cbc(); 52 case 24: 53 return EVP_aes_192_cbc(); 54 case 32: 55 return EVP_aes_256_cbc(); 56 }; 57 *error = KM_ERROR_UNSUPPORTED_KEY_SIZE; 58 break; 59 60 case KM_MODE_CTR: 61 switch (key_size) { 62 case 16: 63 return EVP_aes_128_ctr(); 64 case 24: 65 return EVP_aes_192_ctr(); 66 case 32: 67 return EVP_aes_256_ctr(); 68 } 69 *error = KM_ERROR_UNSUPPORTED_KEY_SIZE; 70 break; 71 72 case KM_MODE_GCM: 73 switch (key_size) { 74 case 16: 75 return EVP_aes_128_gcm(); 76 case 24: 77 return EVP_aes_192_gcm(); 78 case 32: 79 return EVP_aes_256_gcm(); 80 } 81 *error = KM_ERROR_UNSUPPORTED_KEY_SIZE; 82 break; 83 84 default: 85 *error = KM_ERROR_UNSUPPORTED_BLOCK_MODE; 86 break; 87 } 88 89 assert(*error != KM_ERROR_OK); 90 return nullptr; 91 } 92 93 static AesEvpCipherDescription description; 94 const EvpCipherDescription& AesOperationFactory::GetCipherDescription() const { 95 return description; 96 } 97 98 } // namespace keymaster 99
