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
 * 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
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 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
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 */

#include "config.h"
#include "CryptoAlgorithmHMAC.h"

#if ENABLE(SUBTLE_CRYPTO)

#include "CryptoAlgorithmHmacParamsDeprecated.h"
#include "CryptoKeyHMAC.h"
#include "ExceptionCode.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;
    }
}

static Vector<uint8_t> calculateSignature(CCHmacAlgorithm algorithm, const Vector<uint8_t>& key, const CryptoOperationData& data)
{
    size_t digestLength;
    switch (algorithm) {
    case kCCHmacAlgSHA1:
        digestLength = CC_SHA1_DIGEST_LENGTH;
        break;
    case kCCHmacAlgSHA224:
        digestLength = CC_SHA224_DIGEST_LENGTH;
        break;
    case kCCHmacAlgSHA256:
        digestLength = CC_SHA256_DIGEST_LENGTH;
        break;
    case kCCHmacAlgSHA384:
        digestLength = CC_SHA384_DIGEST_LENGTH;
        break;
    case kCCHmacAlgSHA512:
        digestLength = CC_SHA512_DIGEST_LENGTH;
        break;
    default:
        ASSERT_NOT_REACHED();
        return Vector<uint8_t>();
    }

    Vector<uint8_t> result(digestLength);
    const void* keyData = key.data() ? key.data() : reinterpret_cast<const uint8_t*>(""); // <rdar://problem/15467425> HMAC crashes when key pointer is null.
    CCHmac(algorithm, keyData, key.size(), data.first, data.second, result.data());
    return result;
}

ExceptionOr<void> CryptoAlgorithmHMAC::platformSign(const CryptoAlgorithmHmacParamsDeprecated& parameters, const CryptoKeyHMAC& key, const CryptoOperationData& data, VectorCallback&& callback, VoidCallback&&)
{
    auto algorithm = commonCryptoHMACAlgorithm(parameters.hash);
    if (!algorithm)
        return Exception { NOT_SUPPORTED_ERR };
    callback(calculateSignature(*algorithm, key.key(), data));
    return { };
}

ExceptionOr<void> CryptoAlgorithmHMAC::platformVerify(const CryptoAlgorithmHmacParamsDeprecated& parameters, const CryptoKeyHMAC& key, const CryptoOperationData& expectedSignature, const CryptoOperationData& data, BoolCallback&& callback, VoidCallback&&)
{
    auto algorithm = commonCryptoHMACAlgorithm(parameters.hash);
    if (!algorithm)
        return Exception { NOT_SUPPORTED_ERR };

    auto signature = calculateSignature(*algorithm, key.key(), data);

    // Using a constant time comparison to prevent timing attacks.
    bool result = signature.size() == expectedSignature.second && !constantTimeMemcmp(signature.data(), expectedSignature.first, signature.size());

    callback(result);

    return { };
}

}

#endif // ENABLE(SUBTLE_CRYPTO)