87 lines
2.6 KiB
C++
87 lines
2.6 KiB
C++
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/*
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* Copyright (C) 2018 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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//#define LOG_NDEBUG 0
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#define LOG_TAG "hidl_ClearkeyDecryptor"
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#include <utils/Log.h>
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#include <openssl/aes.h>
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#include "AesCtrDecryptor.h"
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#include "ClearKeyTypes.h"
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namespace android {
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namespace hardware {
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namespace drm {
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namespace V1_4 {
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namespace clearkey {
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using ::android::hardware::drm::V1_0::SubSample;
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using ::android::hardware::drm::V1_0::Status;
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static const size_t kBlockBitCount = kBlockSize * 8;
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Status AesCtrDecryptor::decrypt(
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const std::vector<uint8_t>& key,
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const Iv iv, const uint8_t* source,
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uint8_t* destination,
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const std::vector<SubSample> subSamples,
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size_t numSubSamples,
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size_t* bytesDecryptedOut) {
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uint32_t blockOffset = 0;
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uint8_t previousEncryptedCounter[kBlockSize];
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memset(previousEncryptedCounter, 0, kBlockSize);
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if (key.size() != kBlockSize || (sizeof(Iv) / sizeof(uint8_t)) != kBlockSize) {
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android_errorWriteLog(0x534e4554, "63982768");
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return Status::ERROR_DRM_DECRYPT;
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}
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size_t offset = 0;
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AES_KEY opensslKey;
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AES_set_encrypt_key(key.data(), kBlockBitCount, &opensslKey);
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Iv opensslIv;
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memcpy(opensslIv, iv, sizeof(opensslIv));
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for (size_t i = 0; i < numSubSamples; ++i) {
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const SubSample& subSample = subSamples[i];
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if (subSample.numBytesOfClearData > 0) {
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memcpy(destination + offset, source + offset,
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subSample.numBytesOfClearData);
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offset += subSample.numBytesOfClearData;
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}
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if (subSample.numBytesOfEncryptedData > 0) {
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AES_ctr128_encrypt(source + offset, destination + offset,
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subSample.numBytesOfEncryptedData, &opensslKey,
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opensslIv, previousEncryptedCounter,
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&blockOffset);
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offset += subSample.numBytesOfEncryptedData;
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}
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}
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*bytesDecryptedOut = offset;
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return Status::OK;
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}
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} // namespace clearkey
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} // namespace V1_4
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} // namespace drm
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} // namespace hardware
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} // namespace android
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