98 lines
3.4 KiB
C++
98 lines
3.4 KiB
C++
/*
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* Copyright (C) 2014 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 "ClearKeyCryptoPlugin"
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#include <utils/Log.h>
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#include <media/stagefright/MediaErrors.h>
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#include "CryptoPlugin.h"
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#include "SessionLibrary.h"
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namespace clearkeydrm {
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using android::Vector;
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using android::AString;
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using android::status_t;
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// Returns negative values for error code and positive values for the size of
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// decrypted data. In theory, the output size can be larger than the input
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// size, but in practice this will never happen for AES-CTR.
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ssize_t CryptoPlugin::decrypt(bool secure, const KeyId keyId, const Iv iv,
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Mode mode, const Pattern &/* pattern */, const void* srcPtr,
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const SubSample* subSamples, size_t numSubSamples,
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void* dstPtr, AString* errorDetailMsg) {
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if (secure) {
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errorDetailMsg->setTo("Secure decryption is not supported with "
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"ClearKey.");
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return android::ERROR_DRM_CANNOT_HANDLE;
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}
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if (mode == kMode_Unencrypted) {
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size_t offset = 0;
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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.mNumBytesOfEncryptedData != 0) {
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errorDetailMsg->setTo(
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"Encrypted subsamples found in allegedly unencrypted "
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"data.");
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return android::ERROR_DRM_DECRYPT;
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}
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if (subSample.mNumBytesOfClearData != 0) {
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memcpy(reinterpret_cast<uint8_t*>(dstPtr) + offset,
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reinterpret_cast<const uint8_t*>(srcPtr) + offset,
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subSample.mNumBytesOfClearData);
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offset += subSample.mNumBytesOfClearData;
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}
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}
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return static_cast<ssize_t>(offset);
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} else if (mode == kMode_AES_CTR) {
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size_t bytesDecrypted;
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status_t res = mSession->decrypt(keyId, iv, srcPtr, dstPtr, subSamples,
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numSubSamples, &bytesDecrypted);
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if (res == android::OK) {
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return static_cast<ssize_t>(bytesDecrypted);
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} else {
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errorDetailMsg->setTo("Decryption Error");
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return static_cast<ssize_t>(res);
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}
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} else {
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errorDetailMsg->setTo(
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"Selected encryption mode is not supported by the ClearKey DRM "
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"Plugin.");
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return android::ERROR_DRM_CANNOT_HANDLE;
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}
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}
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android::status_t CryptoPlugin::setMediaDrmSession(
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const android::Vector<uint8_t>& sessionId) {
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if (!sessionId.size()) {
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mSession.clear();
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} else {
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mSession = SessionLibrary::get()->findSession(sessionId);
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if (!mSession.get()) {
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return android::ERROR_DRM_SESSION_NOT_OPENED;
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}
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}
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return android::OK;
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}
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} // namespace clearkeydrm
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