| /* |
| * Copyright (C) 2018 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| //#define LOG_NDEBUG 0 |
| #define LOG_TAG "hidl_ClearkeyDecryptor" |
| #include <utils/Log.h> |
| |
| #include <openssl/aes.h> |
| |
| #include "AesCtrDecryptor.h" |
| #include "ClearKeyTypes.h" |
| |
| namespace android { |
| namespace hardware { |
| namespace drm { |
| namespace V1_2 { |
| namespace clearkey { |
| |
| using ::android::hardware::drm::V1_0::SubSample; |
| using ::android::hardware::drm::V1_0::Status; |
| |
| static const size_t kBlockBitCount = kBlockSize * 8; |
| |
| Status AesCtrDecryptor::decrypt( |
| const std::vector<uint8_t>& key, |
| const Iv iv, const uint8_t* source, |
| uint8_t* destination, |
| const std::vector<SubSample> subSamples, |
| size_t numSubSamples, |
| size_t* bytesDecryptedOut) { |
| uint32_t blockOffset = 0; |
| uint8_t previousEncryptedCounter[kBlockSize]; |
| memset(previousEncryptedCounter, 0, kBlockSize); |
| |
| if (key.size() != kBlockSize || (sizeof(Iv) / sizeof(uint8_t)) != kBlockSize) { |
| android_errorWriteLog(0x534e4554, "63982768"); |
| return Status::ERROR_DRM_DECRYPT; |
| } |
| |
| size_t offset = 0; |
| AES_KEY opensslKey; |
| AES_set_encrypt_key(key.data(), kBlockBitCount, &opensslKey); |
| Iv opensslIv; |
| memcpy(opensslIv, iv, sizeof(opensslIv)); |
| |
| for (size_t i = 0; i < numSubSamples; ++i) { |
| const SubSample& subSample = subSamples[i]; |
| |
| if (subSample.numBytesOfClearData > 0) { |
| memcpy(destination + offset, source + offset, |
| subSample.numBytesOfClearData); |
| offset += subSample.numBytesOfClearData; |
| } |
| |
| if (subSample.numBytesOfEncryptedData > 0) { |
| AES_ctr128_encrypt(source + offset, destination + offset, |
| subSample.numBytesOfEncryptedData, &opensslKey, |
| opensslIv, previousEncryptedCounter, |
| &blockOffset); |
| offset += subSample.numBytesOfEncryptedData; |
| } |
| } |
| |
| *bytesDecryptedOut = offset; |
| return Status::OK; |
| } |
| |
| } // namespace clearkey |
| } // namespace V1_2 |
| } // namespace drm |
| } // namespace hardware |
| } // namespace android |
| |