CryptoAlgorithmHMACMac.cpp   [plain text]


/*
 * Copyright (C) 2013 Apple Inc. All rights reserved.
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 * 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
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 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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#include "config.h"
#include "CryptoAlgorithmHMAC.h"

#if ENABLE(SUBTLE_CRYPTO)

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

// FIXME: We should change data to Vector<uint8_t> type once WebKitSubtleCrypto is deprecated.
// https://bugs.webkit.org/show_bug.cgi?id=164939
static Vector<uint8_t> calculateSignature(CCHmacAlgorithm algorithm, const Vector<uint8_t>& key, const uint8_t* data, size_t dataLength)
{
    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);
    CCHmac(algorithm, key.data(), key.size(), data, dataLength, result.data());
    return result;
}

void CryptoAlgorithmHMAC::platformSign(Ref<CryptoKey>&& key, Vector<uint8_t>&& data, VectorCallback&& callback, ExceptionCallback&& exceptionCallback, ScriptExecutionContext& context, WorkQueue& workQueue)
{
    context.ref();
    workQueue.dispatch([key = WTFMove(key), data = WTFMove(data), callback = WTFMove(callback), exceptionCallback = WTFMove(exceptionCallback), &context]() mutable {
        auto& hmacKey = downcast<CryptoKeyHMAC>(key.get());
        auto algorithm = commonCryptoHMACAlgorithm(hmacKey.hashAlgorithmIdentifier());
        if (!algorithm) {
            // We should only dereference callbacks after being back to the Document/Worker threads.
            context.postTask([exceptionCallback = WTFMove(exceptionCallback), callback = WTFMove(callback)](ScriptExecutionContext& context) {
                exceptionCallback(OperationError);
                context.deref();
            });
            return;
        }
        auto result = calculateSignature(*algorithm, hmacKey.key(), data.data(), data.size());
        // We should only dereference callbacks after being back to the Document/Worker threads.
        context.postTask([callback = WTFMove(callback), result = WTFMove(result), exceptionCallback = WTFMove(exceptionCallback)](ScriptExecutionContext& context) {
            callback(result);
            context.deref();
        });
    });

}

void CryptoAlgorithmHMAC::platformVerify(Ref<CryptoKey>&& key, Vector<uint8_t>&& signature, Vector<uint8_t>&& data, BoolCallback&& callback, ExceptionCallback&& exceptionCallback, ScriptExecutionContext& context, WorkQueue& workQueue)
{
    context.ref();
    workQueue.dispatch([key = WTFMove(key), signature = WTFMove(signature), data = WTFMove(data), callback = WTFMove(callback), exceptionCallback = WTFMove(exceptionCallback), &context]() mutable {
        auto& hmacKey = downcast<CryptoKeyHMAC>(key.get());
        auto algorithm = commonCryptoHMACAlgorithm(hmacKey.hashAlgorithmIdentifier());
        if (!algorithm) {
            // We should only dereference callbacks after being back to the Document/Worker threads.
            context.postTask([exceptionCallback = WTFMove(exceptionCallback), callback = WTFMove(callback)](ScriptExecutionContext& context) {
                exceptionCallback(OperationError);
                context.deref();
            });
            return;
        }
        auto expectedSignature = calculateSignature(*algorithm, hmacKey.key(), data.data(), data.size());
        // Using a constant time comparison to prevent timing attacks.
        bool result = signature.size() == expectedSignature.size() && !constantTimeMemcmp(expectedSignature.data(), signature.data(), expectedSignature.size());
        // We should only dereference callbacks after being back to the Document/Worker threads.
        context.postTask([callback = WTFMove(callback), result, exceptionCallback = WTFMove(exceptionCallback)](ScriptExecutionContext& context) {
            callback(result);
            context.deref();
        });
    });
}

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.first, data.second));
    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.first, data.second);

    // 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)