diff options
Diffstat (limited to 'drm/mediadrm/plugins/clearkey/CryptoPlugin.cpp')
-rw-r--r-- | drm/mediadrm/plugins/clearkey/CryptoPlugin.cpp | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/drm/mediadrm/plugins/clearkey/CryptoPlugin.cpp b/drm/mediadrm/plugins/clearkey/CryptoPlugin.cpp new file mode 100644 index 0000000..adad136 --- /dev/null +++ b/drm/mediadrm/plugins/clearkey/CryptoPlugin.cpp @@ -0,0 +1,83 @@ +/* + * Copyright (C) 2014 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 "ClearKeyCryptoPlugin" +#include <utils/Log.h> + +#include <media/stagefright/MediaErrors.h> +#include <utils/Errors.h> + +#include "CryptoPlugin.h" + +namespace clearkeydrm { + +using android::Vector; +using android::AString; +using android::status_t; + +// Returns negative values for error code and positive values for the size of +// decrypted data. In theory, the output size can be larger than the input +// size, but in practice this will never happen for AES-CTR. +ssize_t CryptoPlugin::decrypt(bool secure, const KeyId keyId, const Iv iv, + Mode mode, const void* srcPtr, + const SubSample* subSamples, size_t numSubSamples, + void* dstPtr, AString* errorDetailMsg) { + if (secure) { + errorDetailMsg->setTo("Secure decryption is not supported with " + "ClearKey."); + return android::ERROR_DRM_CANNOT_HANDLE; + } + + if (mode == kMode_Unencrypted) { + size_t offset = 0; + for (size_t i = 0; i < numSubSamples; ++i) { + const SubSample& subSample = subSamples[i]; + + if (subSample.mNumBytesOfEncryptedData != 0) { + errorDetailMsg->setTo( + "Encrypted subsamples found in allegedly unencrypted " + "data."); + return android::ERROR_DRM_DECRYPT; + } + + if (subSample.mNumBytesOfClearData != 0) { + memcpy(reinterpret_cast<uint8_t*>(dstPtr) + offset, + reinterpret_cast<const uint8_t*>(srcPtr) + offset, + subSample.mNumBytesOfClearData); + offset += subSample.mNumBytesOfClearData; + } + } + return static_cast<ssize_t>(offset); + } else if (mode == kMode_AES_CTR) { + size_t bytesDecrypted; + status_t res = mSession->decrypt(keyId, iv, srcPtr, dstPtr, subSamples, + numSubSamples, &bytesDecrypted); + if (res == android::OK) { + return static_cast<ssize_t>(bytesDecrypted); + } else { + errorDetailMsg->setTo("Decryption Error"); + return static_cast<ssize_t>(res); + } + } else { + errorDetailMsg->setTo( + "Selected encryption mode is not supported by the ClearKey DRM " + "Plugin."); + return android::ERROR_DRM_CANNOT_HANDLE; + } +} + +} // namespace clearkeydrm |