Session.cpp revision 1fe11a5d1b7932a8a4a4e6e8cf1aedd21fcdb3aa 
1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17//#define LOG_NDEBUG 0
18#define LOG_TAG "ClearKeyCryptoPlugin"
19#include <utils/Log.h>
20
21#include <media/stagefright/MediaErrors.h>
22#include <utils/String8.h>
23
24#include "Session.h"
25
26#include "AesCtrDecryptor.h"
27#include "InitDataParser.h"
28#include "JsonWebKey.h"
29
30namespace clearkeydrm {
31
32using android::Mutex;
33using android::String8;
34using android::Vector;
35using android::status_t;
36
37status_t Session::getKeyRequest(
38        const Vector<uint8_t>& initData,
39        const String8& initDataType,
40        Vector<uint8_t>* keyRequest) const {
41    InitDataParser parser;
42    return parser.parse(initData, initDataType, keyRequest);
43}
44
45status_t Session::provideKeyResponse(const Vector<uint8_t>& response) {
46    String8 responseString(
47            reinterpret_cast<const char*>(response.array()), response.size());
48    KeyMap keys;
49
50    Mutex::Autolock lock(mMapLock);
51    JsonWebKey parser;
52    if (parser.extractKeysFromJsonWebKeySet(responseString, &keys)) {
53        for (size_t i = 0; i < keys.size(); ++i) {
54            const KeyMap::key_type& keyId = keys.keyAt(i);
55            const KeyMap::value_type& key = keys.valueAt(i);
56            mKeyMap.add(keyId, key);
57        }
58        return android::OK;
59    } else {
60        return android::ERROR_DRM_UNKNOWN;
61    }
62}
63
64status_t Session::decrypt(
65        const KeyId keyId, const Iv iv, const void* source,
66        void* destination, const SubSample* subSamples,
67        size_t numSubSamples, size_t* bytesDecryptedOut) {
68    Mutex::Autolock lock(mMapLock);
69
70    Vector<uint8_t> keyIdVector;
71    keyIdVector.appendArray(keyId, kBlockSize);
72    if (mKeyMap.indexOfKey(keyIdVector) < 0) {
73        return android::ERROR_DRM_NO_LICENSE;
74    }
75
76    const Vector<uint8_t>& key = mKeyMap.valueFor(keyIdVector);
77    AesCtrDecryptor decryptor;
78    return decryptor.decrypt(
79            key, iv,
80            reinterpret_cast<const uint8_t*>(source),
81            reinterpret_cast<uint8_t*>(destination), subSamples,
82            numSubSamples, bytesDecryptedOut);
83}
84
85} // namespace clearkeydrm
86