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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 "CryptoAlgorithmECDH.h"
#if ENABLE(SUBTLE_CRYPTO)
#include "CryptoKeyEC.h"
#include "ScriptExecutionContext.h"
#include <pal/crypto/gcrypt/Handle.h>
#include <pal/crypto/gcrypt/Utilities.h>
namespace WebCore {
static std::optional<Vector<uint8_t>> gcryptDerive(gcry_sexp_t baseKeySexp, gcry_sexp_t publicKeySexp)
{
// First, retrieve private key data, which is roughly of the following form:
// (private-key
// (ecc
// ...
// (d ...)))
PAL::GCrypt::Handle<gcry_sexp_t> dataSexp;
{
PAL::GCrypt::Handle<gcry_sexp_t> dSexp(gcry_sexp_find_token(baseKeySexp, "d", 0));
if (!dSexp)
return std::nullopt;
size_t dataLength = 0;
const char* data = gcry_sexp_nth_data(dSexp, 1, &dataLength);
if (!data)
return std::nullopt;
gcry_sexp_build(&dataSexp, nullptr, "(data(flags raw)(value %b))", dataLength, data);
if (!dataSexp)
return std::nullopt;
}
// Encrypt the data s-expression with the public key.
PAL::GCrypt::Handle<gcry_sexp_t> cipherSexp;
gcry_error_t error = gcry_pk_encrypt(&cipherSexp, dataSexp, publicKeySexp);
if (error != GPG_ERR_NO_ERROR) {
PAL::GCrypt::logError(error);
return std::nullopt;
}
// Retrieve the shared point value from the generated s-expression, which is of the following form:
// (enc-val
// (ecdh
// (s ...)
// (e ...)))
Vector<uint8_t> output;
{
PAL::GCrypt::Handle<gcry_sexp_t> sSexp(gcry_sexp_find_token(cipherSexp, "s", 0));
if (!sSexp)
return std::nullopt;
PAL::GCrypt::Handle<gcry_mpi_t> sMPI(gcry_sexp_nth_mpi(sSexp, 1, GCRYMPI_FMT_USG));
if (!sMPI)
return std::nullopt;
PAL::GCrypt::Handle<gcry_mpi_point_t> point(gcry_mpi_point_new(0));
if (!point)
return std::nullopt;
error = gcry_mpi_ec_decode_point(point, sMPI, nullptr);
if (error != GPG_ERR_NO_ERROR)
return std::nullopt;
PAL::GCrypt::Handle<gcry_mpi_t> xMPI(gcry_mpi_new(0));
if (!xMPI)
return std::nullopt;
// We're only interested in the x-coordinate.
gcry_mpi_point_snatch_get(xMPI, nullptr, nullptr, point.release());
size_t dataLength = 0;
error = gcry_mpi_print(GCRYMPI_FMT_USG, nullptr, 0, &dataLength, xMPI);
if (error != GPG_ERR_NO_ERROR) {
PAL::GCrypt::logError(error);
return std::nullopt;
}
output.grow(dataLength);
error = gcry_mpi_print(GCRYMPI_FMT_USG, output.data(), output.size(), nullptr, xMPI);
if (error != GPG_ERR_NO_ERROR) {
PAL::GCrypt::logError(error);
return std::nullopt;
}
}
return output;
}
void CryptoAlgorithmECDH::platformDeriveBits(Ref<CryptoKey>&& baseKey, Ref<CryptoKey>&& publicKey, size_t length, Callback&& callback, ScriptExecutionContext& context, WorkQueue& workQueue)
{
context.ref();
workQueue.dispatch(
[baseKey = WTFMove(baseKey), publicKey = WTFMove(publicKey), length, callback = WTFMove(callback), &context]() mutable {
auto& ecBaseKey = downcast<CryptoKeyEC>(baseKey.get());
auto& ecPublicKey = downcast<CryptoKeyEC>(publicKey.get());
auto output = gcryptDerive(ecBaseKey.platformKey(), ecPublicKey.platformKey());
context.postTask(
[output = WTFMove(output), length, callback = WTFMove(callback)](ScriptExecutionContext& context) mutable {
callback(WTFMove(output), length);
context.deref();
});
});
}
} // namespace WebCore
#endif // ENABLE(SUBTLE_CRYPTO)
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