adb98d80d3
Includes change to WB_License_Create() so that it includes a separate parameter that specifies the init data used for Provider Keys. This updates the repo to match the internal repo at commit: 8c1c4338906a32eed83eb63702690d1f02ff7cd0
83 lines
2.4 KiB
C++
83 lines
2.4 KiB
C++
// Copyright 2020 Google LLC. All Rights Reserved.
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#include "crypto_utils/aes_ctr_encryptor.h"
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#include <cstddef>
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#include <cstdint>
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#include <vector>
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#include "base/check.h"
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#include "base/logging.h"
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namespace widevine {
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namespace {
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constexpr size_t kAesBlockSize = 16;
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// Increment an 8-byte counter by 1. Return true if overflowed.
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bool Increment64(uint8_t* counter) {
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DCHECK(counter);
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for (int i = 7; i >= 0; --i) {
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if (++counter[i] != 0)
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return false;
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}
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return true;
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}
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} // namespace
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AesCtrEncryptor::~AesCtrEncryptor() {}
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bool AesCtrEncryptor::SetKey(const uint8_t* key, size_t key_size) {
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DCHECK(key);
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if (key_size != kAesBlockSize && key_size != kAesBlockSize * 2) {
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LOG(WARNING) << "Incorrect key size " << key_size;
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return false;
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}
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if (AES_set_encrypt_key(key, static_cast<int>(key_size * 8), &aes_key_) !=
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0) {
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LOG(WARNING) << "Invalid AES key.";
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return false;
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}
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aes_key_size_ = key_size;
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return true;
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}
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bool AesCtrEncryptor::Encrypt(const uint8_t* iv,
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size_t iv_size,
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const uint8_t* input_data,
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size_t input_data_size,
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uint8_t* output_data) {
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DCHECK(iv);
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DCHECK(input_data);
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DCHECK(output_data);
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if (aes_key_size_ == 0) {
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LOG(WARNING) << "This class has not been initialized.";
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return false;
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}
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// IV is allowed to be either AES BLOCK size or half of it.
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if (iv_size != kAesBlockSize && iv_size != kAesBlockSize / 2) {
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LOG(WARNING) << "Invalid IV size " << iv_size;
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return false;
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}
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std::vector<uint8_t> counter(iv, iv + iv_size);
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counter.resize(kAesBlockSize);
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std::vector<uint8_t> encrypted_counter(kAesBlockSize);
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for (size_t i = 0; i < input_data_size; i += 16) {
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AES_encrypt(counter.data(), encrypted_counter.data(), &aes_key_);
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// As mentioned in ISO/IEC 23001-7:2016 CENC spec, of the 16 byte counter
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// block, bytes 8 to 15 (i.e. the least significant bytes) are used as a
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// simple 64 bit unsigned integer that is incremented by one for each
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// subsequent block of sample data processed and is kept in network byte
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// order.
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Increment64(counter.data() + 8);
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for (size_t j = 0; j < kAesBlockSize && i + j < input_data_size; j++)
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output_data[i + j] = input_data[i + j] ^ encrypted_counter[j];
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}
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return true;
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}
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} // namespace widevine
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