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/*
* Copyright (C) 2017 Apple Inc. All rights reserved.
* Copyright (C) 2017 Metrological Group B.V.
* Copyright (C) 2017 Igalia S.L.
*
* 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 "CryptoAlgorithmECDSA.h"
#if ENABLE(WEB_CRYPTO)
#include "CryptoAlgorithmEcdsaParams.h"
#include "CryptoKeyEC.h"
#include "GCryptUtilities.h"
#include <pal/crypto/CryptoDigest.h>
namespace WebCore {
static bool extractECDSASignatureInteger(Vector<uint8_t>& signature, gcry_sexp_t signatureSexp, const char* integerName, size_t keySizeInBytes)
{
// Retrieve byte data of the specified integer.
PAL::GCrypt::Handle<gcry_sexp_t> integerSexp(gcry_sexp_find_token(signatureSexp, integerName, 0));
if (!integerSexp)
return false;
auto integerData = mpiData(integerSexp);
if (!integerData)
return false;
size_t dataSize = integerData->size();
if (dataSize >= keySizeInBytes) {
// Append the last `keySizeInBytes` bytes of the data Vector, if available.
signature.append(&integerData->at(dataSize - keySizeInBytes), keySizeInBytes);
} else {
// If not, prefix the binary data with zero bytes.
for (size_t paddingSize = keySizeInBytes - dataSize; paddingSize > 0; --paddingSize)
signature.uncheckedAppend(0x00);
signature.appendVector(*integerData);
}
return true;
}
static std::optional<Vector<uint8_t>> gcryptSign(gcry_sexp_t keySexp, const Vector<uint8_t>& data, CryptoAlgorithmIdentifier hashAlgorithmIdentifier, size_t keySizeInBytes)
{
// Perform digest operation with the specified algorithm on the given data.
Vector<uint8_t> dataHash;
{
auto digestAlgorithm = hashCryptoDigestAlgorithm(hashAlgorithmIdentifier);
if (!digestAlgorithm)
return std::nullopt;
auto digest = PAL::CryptoDigest::create(*digestAlgorithm);
if (!digest)
return std::nullopt;
digest->addBytes(data.data(), data.size());
dataHash = digest->computeHash();
}
// Construct the data s-expression that contains raw hashed data.
PAL::GCrypt::Handle<gcry_sexp_t> dataSexp;
{
auto shaAlgorithm = hashAlgorithmName(hashAlgorithmIdentifier);
if (!shaAlgorithm)
return std::nullopt;
gcry_error_t error = gcry_sexp_build(&dataSexp, nullptr, "(data(flags raw)(hash %s %b))",
*shaAlgorithm, dataHash.size(), dataHash.data());
if (error != GPG_ERR_NO_ERROR) {
PAL::GCrypt::logError(error);
return std::nullopt;
}
}
// Perform the PK signing, retrieving a sig-val s-expression of the following form:
// (sig-val
// (dsa
// (r r-mpi)
// (s s-mpi)))
PAL::GCrypt::Handle<gcry_sexp_t> signatureSexp;
gcry_error_t error = gcry_pk_sign(&signatureSexp, dataSexp, keySexp);
if (error != GPG_ERR_NO_ERROR) {
PAL::GCrypt::logError(error);
return std::nullopt;
}
// Retrieve MPI data of the resulting r and s integers. They are concatenated into
// a single buffer, properly accounting for integers that don't match the key in size.
Vector<uint8_t> signature;
signature.reserveInitialCapacity(keySizeInBytes * 2);
if (!extractECDSASignatureInteger(signature, signatureSexp, "r", keySizeInBytes)
|| !extractECDSASignatureInteger(signature, signatureSexp, "s", keySizeInBytes))
return std::nullopt;
return signature;
}
static std::optional<bool> gcryptVerify(gcry_sexp_t keySexp, const Vector<uint8_t>& signature, const Vector<uint8_t>& data, CryptoAlgorithmIdentifier hashAlgorithmIdentifier, size_t keySizeInBytes)
{
// Bail if the signature size isn't double the key size (i.e. concatenated r and s components).
if (signature.size() != keySizeInBytes * 2)
return false;
// Perform digest operation with the specified algorithm on the given data.
Vector<uint8_t> dataHash;
{
auto digestAlgorithm = hashCryptoDigestAlgorithm(hashAlgorithmIdentifier);
if (!digestAlgorithm)
return std::nullopt;
auto digest = PAL::CryptoDigest::create(*digestAlgorithm);
if (!digest)
return std::nullopt;
digest->addBytes(data.data(), data.size());
dataHash = digest->computeHash();
}
// Construct the sig-val s-expression, extracting the r and s components from the signature vector.
PAL::GCrypt::Handle<gcry_sexp_t> signatureSexp;
gcry_error_t error = gcry_sexp_build(&signatureSexp, nullptr, "(sig-val(ecdsa(r %b)(s %b)))",
keySizeInBytes, signature.data(), keySizeInBytes, signature.data() + keySizeInBytes);
if (error != GPG_ERR_NO_ERROR) {
PAL::GCrypt::logError(error);
return std::nullopt;
}
// Construct the data s-expression that contains raw hashed data.
PAL::GCrypt::Handle<gcry_sexp_t> dataSexp;
{
auto shaAlgorithm = hashAlgorithmName(hashAlgorithmIdentifier);
if (!shaAlgorithm)
return std::nullopt;
error = gcry_sexp_build(&dataSexp, nullptr, "(data(flags raw)(hash %s %b))",
*shaAlgorithm, dataHash.size(), dataHash.data());
if (error != GPG_ERR_NO_ERROR) {
PAL::GCrypt::logError(error);
return std::nullopt;
}
}
// Perform the PK verification. We report success if there's no error returned, or
// a failure in any other case. OperationError should not be returned at this point,
// avoiding spilling information about the exact cause of verification failure.
error = gcry_pk_verify(signatureSexp, dataSexp, keySexp);
return { error == GPG_ERR_NO_ERROR };
}
ExceptionOr<Vector<uint8_t>> CryptoAlgorithmECDSA::platformSign(const CryptoAlgorithmEcdsaParams& parameters, const CryptoKeyEC& key, const Vector<uint8_t>& data)
{
auto output = gcryptSign(key.platformKey(), data, parameters.hashIdentifier, (key.keySizeInBits() + 7) / 8);
if (!output)
return Exception { OperationError };
return WTFMove(*output);
}
ExceptionOr<bool> CryptoAlgorithmECDSA::platformVerify(const CryptoAlgorithmEcdsaParams& parameters, const CryptoKeyEC& key, const Vector<uint8_t>& signature, const Vector<uint8_t>& data)
{
auto output = gcryptVerify(key.platformKey(), signature, data, parameters.hashIdentifier, (key.keySizeInBits() + 7)/ 8);
if (!output)
return Exception { OperationError };
return WTFMove(*output);
}
} // namespace WebCore
#endif // ENABLE(WEB_CRYPTO)
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