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Commit 16dfdcff authored by John "Juce" Bruce's avatar John "Juce" Bruce Committed by Edwin Wong
Browse files

Implement OpenSSL-Based Decryptor 

Implements an object that does AES-CTR-128 by invoking OpenSSL.

Change-Id: I8457899ec8b69bd8f0d727029985c9580911cf99
parent 47a86fb3

drm/mediadrm/plugins/clearkey/AesCtrDecryptor.cpp

0 → 100644
+67 −0
Original line number Diff line number Diff line 
/*

 * 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 <openssl/aes.h>



#include "AesCtrDecryptor.h"



namespace clearkeydrm {



static const size_t kBlockBitCount = kBlockSize * 8;



android::status_t AesCtrDecryptor::decrypt(const android::Vector<uint8_t>& key,

        const Iv iv, const uint8_t* source,

        uint8_t* destination,

        const SubSample* subSamples,

        size_t numSubSamples,

        size_t* bytesDecryptedOut) {

    uint32_t blockOffset = 0;

    uint8_t previousEncryptedCounter[kBlockSize];

    memset(previousEncryptedCounter, 0, kBlockSize);



    size_t offset = 0;

    AES_KEY opensslKey;

    AES_set_encrypt_key(key.array(), kBlockBitCount, &opensslKey);

    Iv opensslIv;

    memcpy(opensslIv, iv, sizeof(opensslIv));



    for (size_t i = 0; i < numSubSamples; ++i) {

        const SubSample& subSample = subSamples[i];



        if (subSample.mNumBytesOfClearData > 0) {

            memcpy(destination + offset, source + offset,

                    subSample.mNumBytesOfClearData);

            offset += subSample.mNumBytesOfClearData;

        }



        if (subSample.mNumBytesOfEncryptedData > 0) {

            AES_ctr128_encrypt(source + offset, destination + offset,

                    subSample.mNumBytesOfEncryptedData, &opensslKey,

                    opensslIv, previousEncryptedCounter,

                    &blockOffset);

            offset += subSample.mNumBytesOfEncryptedData;

        }

    }



    *bytesDecryptedOut = offset;

    return android::OK;

}



} // namespace clearkeydrm

drm/mediadrm/plugins/clearkey/AesCtrDecryptor.h

0 → 100644
+44 −0
Original line number Diff line number Diff line 
/*

 * 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.

 */



#ifndef CLEARKEY_AES_CTR_DECRYPTOR_H_

#define CLEARKEY_AES_CTR_DECRYPTOR_H_



#include <media/stagefright/foundation/ABase.h>

#include <Utils.h>

#include <utils/Errors.h>

#include <utils/Vector.h>



#include "ClearKeyTypes.h"



namespace clearkeydrm {



class AesCtrDecryptor {

public:

    AesCtrDecryptor() {}



    android::status_t decrypt(const android::Vector<uint8_t>& key, const Iv iv,

            const uint8_t* source, uint8_t* destination,

            const SubSample* subSamples, size_t numSubSamples,

            size_t* bytesDecryptedOut);



private:

    DISALLOW_EVIL_CONSTRUCTORS(AesCtrDecryptor);

};



} // namespace clearkeydrm



#endif // CLEARKEY_AES_CTR_DECRYPTOR_H_

drm/mediadrm/plugins/clearkey/Android.mk

+13 −0
Original line number Diff line number Diff line
@@ -17,10 +17,14 @@ LOCAL_PATH:= $(call my-dir) 
include $(CLEAR_VARS)



LOCAL_SRC_FILES := \

    AesCtrDecryptor.cpp \

    JsonWebKey.cpp \

    Utils.cpp \



LOCAL_C_INCLUDES := \

    bionic \

    external/jsmn \

    external/openssl/include \

    frameworks/av/drm/mediadrm/plugins/clearkey \

    frameworks/av/include \

    frameworks/native/include \
@@ -30,10 +34,19 @@ LOCAL_MODULE := libdrmclearkeyplugin 
LOCAL_MODULE_PATH := $(TARGET_OUT_VENDOR_SHARED_LIBRARIES)/mediadrm



LOCAL_SHARED_LIBRARIES := \

    libcrypto \

    liblog \

    libstagefright_foundation \

    libutils \



LOCAL_STATIC_LIBRARIES := \

    libjsmn \



LOCAL_MODULE_TAGS := optional



include $(BUILD_SHARED_LIBRARY)



#########################################################################

# Build unit tests



include $(LOCAL_PATH)/tests/Android.mk

drm/mediadrm/plugins/clearkey/ClearKeyTypes.h

+2 −1
Original line number Diff line number Diff line
@@ -18,12 +18,13 @@ 
#define CLEARKEY_TYPES_H_



#include <media/hardware/CryptoAPI.h>

#include <openssl/aes.h>

#include <utils/KeyedVector.h>

#include <utils/Vector.h>



namespace clearkeydrm {



const uint8_t kBlockSize = 16;

const uint8_t kBlockSize = AES_BLOCK_SIZE;

typedef uint8_t KeyId[kBlockSize];

typedef uint8_t Iv[kBlockSize];