chromium/media/cdm/cbcs_decryptor.cc

// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/40285824): Remove this and convert code to safer constructs.
#pragma allow_unsafe_buffers
#endif

#include "media/cdm/cbcs_decryptor.h"

#include <stdint.h>

#include <algorithm>
#include <string>
#include <vector>

#include "base/containers/span.h"
#include "base/logging.h"
#include "base/memory/scoped_refptr.h"
#include "base/numerics/checked_math.h"
#include "crypto/symmetric_key.h"
#include "media/base/decoder_buffer.h"
#include "media/base/decrypt_config.h"
#include "media/base/encryption_pattern.h"
#include "media/base/subsample_entry.h"
#include "media/cdm/aes_cbc_crypto.h"

namespace media {

namespace {

constexpr size_t kAesBlockSizeInBytes = …;

// Decrypts |input_data| into |output_data|, using the pattern specified in
// |pattern|. |pattern| only applies to full blocks. Any partial block at
// the end is considered unencrypted. |output_data| must have enough room to
// hold |input_data|.size() bytes.
bool DecryptWithPattern(const crypto::SymmetricKey& key,
                        base::span<const uint8_t> iv,
                        const EncryptionPattern& pattern,
                        base::span<const uint8_t> input_data,
                        uint8_t* output_data) { … }

}  // namespace

scoped_refptr<DecoderBuffer> DecryptCbcsBuffer(
    const DecoderBuffer& input,
    const crypto::SymmetricKey& key) { … }

}  // namespace media