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/*
* Copyright (C) 2020 Sony Interactive Entertainment Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "CryptoAlgorithmAES_CTR.h"
#if ENABLE(WEB_CRYPTO)
#include "CryptoAlgorithmAesCtrParams.h"
#include "CryptoKeyAES.h"
#include "OpenSSLCryptoUniquePtr.h"
#include <openssl/evp.h>
namespace WebCore {
static const EVP_CIPHER* aesAlgorithm(size_t keySize)
{
if (keySize * 8 == 128)
return EVP_aes_128_ctr();
if (keySize * 8 == 192)
return EVP_aes_192_ctr();
if (keySize * 8 == 256)
return EVP_aes_256_ctr();
return nullptr;
}
static std::optional<Vector<uint8_t>> crypt(int operation, const Vector<uint8_t>& key, const Vector<uint8_t>& counter, size_t counterLength, const Vector<uint8_t>& inputText)
{
constexpr size_t blockSize = 16;
const EVP_CIPHER* algorithm = aesAlgorithm(key.size());
if (!algorithm)
return std::nullopt;
EvpCipherCtxPtr ctx;
int len;
// Create and initialize the context
if (!(ctx = EvpCipherCtxPtr(EVP_CIPHER_CTX_new())))
return std::nullopt;
const size_t blocks = roundUpToMultipleOf(blockSize, inputText.size()) / blockSize;
// Detect loop
if (counterLength < sizeof(size_t) * 8 && blocks > ((size_t)1 << counterLength))
return std::nullopt;
// Calculate capacity before overflow
CryptoAlgorithmAES_CTR::CounterBlockHelper counterBlockHelper(counter, counterLength);
size_t capacity = counterBlockHelper.countToOverflowSaturating();
// Divide data into two parts if necessary
size_t headSize = inputText.size();
if (capacity < blocks)
headSize = capacity * blockSize;
Vector<uint8_t> outputText(inputText.size());
// First part
{
// Initialize the encryption(decryption) operation
if (1 != EVP_CipherInit_ex(ctx.get(), algorithm, nullptr, key.data(), counter.data(), operation))
return std::nullopt;
// Disable padding
if (1 != EVP_CIPHER_CTX_set_padding(ctx.get(), 0))
return std::nullopt;
// Provide the message to be encrypted(decrypted), and obtain the encrypted(decrypted) output
if (1 != EVP_CipherUpdate(ctx.get(), outputText.data(), &len, inputText.data(), headSize))
return std::nullopt;
// Finalize the encryption(decryption)
if (1 != EVP_CipherFinal_ex(ctx.get(), outputText.data() + len, &len))
return std::nullopt;
}
// Sedond part
if (capacity < blocks) {
size_t tailSize = inputText.size() - headSize;
Vector<uint8_t> remainingCounter = counterBlockHelper.counterVectorAfterOverflow();
// Initialize the encryption(decryption) operation
if (1 != EVP_CipherInit_ex(ctx.get(), algorithm, nullptr, key.data(), remainingCounter.data(), operation))
return std::nullopt;
// Disable padding
if (1 != EVP_CIPHER_CTX_set_padding(ctx.get(), 0))
return std::nullopt;
// Provide the message to be encrypted(decrypted), and obtain the encrypted(decrypted) output
if (1 != EVP_CipherUpdate(ctx.get(), outputText.data() + headSize, &len, inputText.data() + headSize, tailSize))
return std::nullopt;
// Finalize the encryption(decryption)
if (1 != EVP_CipherFinal_ex(ctx.get(), outputText.data() + headSize + len, &len))
return std::nullopt;
}
return outputText;
}
ExceptionOr<Vector<uint8_t>> CryptoAlgorithmAES_CTR::platformEncrypt(const CryptoAlgorithmAesCtrParams& parameters, const CryptoKeyAES& key, const Vector<uint8_t>& plainText)
{
auto output = crypt(1, key.key(), parameters.counterVector(), parameters.length, plainText);
if (!output)
return Exception { OperationError };
return WTFMove(*output);
}
ExceptionOr<Vector<uint8_t>> CryptoAlgorithmAES_CTR::platformDecrypt(const CryptoAlgorithmAesCtrParams& parameters, const CryptoKeyAES& key, const Vector<uint8_t>& cipherText)
{
auto output = crypt(0, key.key(), parameters.counterVector(), parameters.length, cipherText);
if (!output)
return Exception { OperationError };
return WTFMove(*output);
}
} // namespace WebCore
#endif // ENABLE(WEB_CRYPTO)
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