Function encodeEcKey

fdbrpc/JsonWebKeySet.cpp:466–579

}

bool encodeEcKey(rapidjson::Writer<rapidjson::StringBuffer>& writer,
                 StringRef keyName,
                 EVP_PKEY* pKey,
                 const bool isPublic) {
	auto arena = Arena();
	writer.StartObject();
	writer.Key("kty");
	writer.String("EC");
	writer.Key("alg");
	writer.String("ES256");
	writer.Key("kid");
	writer.String(reinterpret_cast<char const*>(keyName.begin()), keyName.size());
#if USE_V3_API
	auto curveNameBuf = std::array<char, 64>{};
	auto curveNameLen = 0ul;
	if (1 != EVP_PKEY_get_utf8_string_param(
	             pKey, OSSL_PKEY_PARAM_GROUP_NAME, curveNameBuf.begin(), sizeof(curveNameBuf), &curveNameLen)) {
		JWK_WRITE_ERROR_OSSL("Get group name from EC PKey");
		return false;
	}
	auto curveName = std::string_view(curveNameBuf.cbegin(), curveNameLen);
	if (curveName != std::string_view("prime256v1")) {
		JWK_WRITE_ERROR("Unsupported EC curve").detail("CurveName", curveName);
		return false;
	}
	writer.Key("crv");
	writer.String("P-256");
#define JWK_WRITE_BN_EC_PARAM(x, param)                                                                                \
	do {                                                                                                               \
		auto x = AutoCPointer(nullptr, &::BN_clear_free);                                                              \
		auto rawX = std::add_pointer_t<BIGNUM>();                                                                      \
		if (1 != ::EVP_PKEY_get_bn_param(pKey, param, &rawX)) {                                                        \
			JWK_WRITE_ERROR_OSSL("EVP_PKEY_get_bn_param(" #param ")");                                                 \
			return false;                                                                                              \
		}                                                                                                              \
		x.reset(rawX);                                                                                                 \
		auto b64##x = bigNumToBase64Url(arena, x);                                                                     \
		writer.Key(#x);                                                                                                \
		writer.String(reinterpret_cast<char const*>(b64##x.begin()), b64##x.size());                                   \
	} while (0)
	// Get and write affine coordinates, X and Y
	JWK_WRITE_BN_EC_PARAM(x, OSSL_PKEY_PARAM_EC_PUB_X);
	JWK_WRITE_BN_EC_PARAM(y, OSSL_PKEY_PARAM_EC_PUB_Y);
	if (!isPublic) {
		JWK_WRITE_BN_EC_PARAM(d, OSSL_PKEY_PARAM_PRIV_KEY);
	}
#undef JWK_WRITE_BN_EC_PARAM
#else // USE_V3_API
	auto ecKey = ::EVP_PKEY_get0_EC_KEY(pKey); // get0 == no refcount, no need to free
	if (!ecKey) {
		JWK_WRITE_ERROR_OSSL("Could not extract EC_KEY from EVP_PKEY");
		return false;
	}
	auto group = ::EC_KEY_get0_group(ecKey);
	if (!group) {
		JWK_WRITE_ERROR("Could not get EC_GROUP from EVP_PKEY");
		return false;
	}