Source/WebCore/crypto/mac/CryptoAlgorithmHMACMac.cpp

/*
 * Copyright (C) 2013 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
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 *
 * 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
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#include "config.h"
#include "CryptoAlgorithmHMAC.h"

#if ENABLE(WEB_CRYPTO)

#include "CryptoKeyHMAC.h"
#include "CryptoUtilitiesCocoa.h"
#include <CommonCrypto/CommonHMAC.h>
#include <wtf/CryptographicUtilities.h>

namespace WebCore {

static std::optional<CCHmacAlgorithm> commonCryptoHMACAlgorithm(CryptoAlgorithmIdentifier hashFunction)
{
    switch (hashFunction) {
    case CryptoAlgorithmIdentifier::SHA_1:
        return kCCHmacAlgSHA1;
    case CryptoAlgorithmIdentifier::SHA_224:
        return kCCHmacAlgSHA224;
    case CryptoAlgorithmIdentifier::SHA_256:
        return kCCHmacAlgSHA256;
    case CryptoAlgorithmIdentifier::SHA_384:
        return kCCHmacAlgSHA384;
    case CryptoAlgorithmIdentifier::SHA_512:
        return kCCHmacAlgSHA512;
    default:
        return std::nullopt;
    }
}

ExceptionOr<Vector<uint8_t>> CryptoAlgorithmHMAC::platformSign(const CryptoKeyHMAC& key, const Vector<uint8_t>& data)
{
    auto algorithm = commonCryptoHMACAlgorithm(key.hashAlgorithmIdentifier());
    if (!algorithm)
        return Exception { OperationError };

    return calculateHMACSignature(*algorithm, key.key(), data.data(), data.size());
}

ExceptionOr<bool> CryptoAlgorithmHMAC::platformVerify(const CryptoKeyHMAC& key, const Vector<uint8_t>& signature, const Vector<uint8_t>& data)
{
    auto algorithm = commonCryptoHMACAlgorithm(key.hashAlgorithmIdentifier());
    if (!algorithm)
        return Exception { OperationError };

    auto expectedSignature = calculateHMACSignature(*algorithm, key.key(), data.data(), data.size());
    // Using a constant time comparison to prevent timing attacks.
    return signature.size() == expectedSignature.size() && !constantTimeMemcmp(expectedSignature.data(), signature.data(), expectedSignature.size());
}

}

#endif // ENABLE(WEB_CRYPTO)