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/*
* Copyright (C) 2020 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. ``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
* 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 "RTCRtpSFrameTransformer.h"
#if ENABLE(WEB_RTC)
#include "CryptoUtilitiesCocoa.h"
#include "SFrameUtils.h"
#include <CommonCrypto/CommonCrypto.h>
namespace WebCore {
ExceptionOr<Vector<uint8_t>> RTCRtpSFrameTransformer::computeSaltKey(const Vector<uint8_t>& rawKey)
{
return deriveHDKFSHA256Bits(rawKey.subspan(0, 16), "SFrame10"_span8, "salt"_span8, 96);
}
static ExceptionOr<Vector<uint8_t>> createBaseSFrameKey(const Vector<uint8_t>& rawKey)
{
return deriveHDKFSHA256Bits(rawKey.subspan(0, 16), "SFrame10"_span8, "key"_span8, 128);
}
ExceptionOr<Vector<uint8_t>> RTCRtpSFrameTransformer::computeAuthenticationKey(const Vector<uint8_t>& rawKey)
{
auto key = createBaseSFrameKey(rawKey);
if (key.hasException())
return key;
return deriveHDKFSHA256Bits(key.returnValue().subspan(0, 16), "SFrame10 AES CM AEAD"_span8, "auth"_span8, 256);
}
ExceptionOr<Vector<uint8_t>> RTCRtpSFrameTransformer::computeEncryptionKey(const Vector<uint8_t>& rawKey)
{
auto key = createBaseSFrameKey(rawKey);
if (key.hasException())
return key;
return deriveHDKFSHA256Bits(key.returnValue().subspan(0, 16), "SFrame10 AES CM AEAD"_span8, "enc"_span8, 128);
}
ExceptionOr<Vector<uint8_t>> RTCRtpSFrameTransformer::decryptData(std::span<const uint8_t> data, const Vector<uint8_t>& iv, const Vector<uint8_t>& key)
{
return transformAESCTR(kCCDecrypt, iv, iv.size(), key, data);
}
ExceptionOr<Vector<uint8_t>> RTCRtpSFrameTransformer::encryptData(std::span<const uint8_t> data, const Vector<uint8_t>& iv, const Vector<uint8_t>& key)
{
return transformAESCTR(kCCEncrypt, iv, iv.size(), key, data);
}
Vector<uint8_t> RTCRtpSFrameTransformer::computeEncryptedDataSignature(const Vector<uint8_t>& nonce, std::span<const uint8_t> header, std::span<const uint8_t> data, const Vector<uint8_t>& key)
{
auto headerLength = encodeBigEndian(header.size());
auto dataLength = encodeBigEndian(data.size());
Vector<uint8_t> result(CC_SHA256_DIGEST_LENGTH);
CCHmacContext context;
CCHmacInit(&context, kCCHmacAlgSHA256, key.data(), key.size());
CCHmacUpdate(&context, headerLength.data(), headerLength.size());
CCHmacUpdate(&context, dataLength.data(), dataLength.size());
CCHmacUpdate(&context, nonce.data(), 12);
CCHmacUpdate(&context, header.data(), header.size());
CCHmacUpdate(&context, data.data(), data.size());
CCHmacFinal(&context, result.data());
return result;
}
void RTCRtpSFrameTransformer::updateAuthenticationSize()
{
if (m_authenticationSize > CC_SHA256_DIGEST_LENGTH)
m_authenticationSize = CC_SHA256_DIGEST_LENGTH;
}
} // namespace WebCore
#endif // ENABLE(WEB_RTC)
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