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/*
* Copyright (C) 2017 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef ESED_PN81A_UTILS_H_
#define ESED_PN81A_UTILS_H_
#include <functional>
#include <string>
#include <hidl/Status.h>
#include <apdu/apdu.h>
#include "pn81a.h"
namespace android {
namespace esed {
namespace pn81a {
// HIDL
using ::android::hardware::Status;
// libapdu
using ::android::CommandApdu;
using ResponseApdu = ::android::ResponseApdu<const std::vector<uint8_t>>;
/**
* Reads a 32-bit integer from an iterator.
* @param first The first position to read from.
* @return A tuple of the value read and an iterator to one after the last position read from.
*/
template<typename InputIt>
std::tuple<uint32_t, InputIt> readBigEndianInt32(InputIt first) {
uint32_t ret;
auto it = first;
ret = *it++ << 24;
ret |= *it++ << 16;
ret |= *it++ << 8;
ret |= *it++;
return {ret, it};
}
/**
* Writes a 32-bit integer to the iterator in big-endian format.
* @param value The value to write.
* @param first The first position in the iterator.
* @return An iterator to one after the last position written to.
*/
template<typename OutputIt>
OutputIt writeBigEndian(const uint32_t value, OutputIt first) {
auto it = first;
*it++ = 0xff & (value >> 24);
*it++ = 0xff & (value >> 16);
*it++ = 0xff & (value >> 8);
*it++ = 0xff & value;
return it;
}
/**
* Transceive a command with the eSE and perform common error checking. When the
* handler is called, it has been checked that the transmission to and reception
* from the eSE was successful and that the response is in a valid format.
*/
template<typename T, T OK, T FAILED>
T transceive(::android::esed::EseInterface& ese, const CommandApdu& command,
std::function<T(const ResponseApdu&)> handler = {}) {
// +1 for max size of extended response, +2 for status bytes
constexpr size_t MAX_RESPONSE_SIZE = std::numeric_limits<uint16_t>::max() + 1 + 2;
std::vector<uint8_t> responseBuffer(MAX_RESPONSE_SIZE);
const int ret = ese.transceive(command.vector(), responseBuffer);
// Check eSE communication was successful
if (ret < 0) {
std::string errMsg = "Failed to transceive data between AP and eSE";
if (ese.error()) {
errMsg += " (" + std::to_string(ese.error_code()) + "): " + ese.error_message();
} else {
errMsg += ": reason unknown";
}
LOG(ERROR) << errMsg;
return FAILED;
}
const size_t recvd = static_cast<size_t>(ret);
// Need to recalculate the maximum response size if this fails
if (recvd > MAX_RESPONSE_SIZE) {
LOG(ERROR) << "eSE response was longer than the buffer, check the buffer size.";
return FAILED;
}
responseBuffer.resize(recvd);
// Check for ISO 7816-4 APDU response format errors
ResponseApdu apdu{responseBuffer};
if (!apdu.ok()) {
LOG(ERROR) << "eSE response was invalid.";
return FAILED;
}
// Call handler if one was provided
if (handler) {
return handler(apdu);
}
return OK;
}
/**
* Checks that the amount of data in the response APDU matches the expected
* value.
*/
template<typename T, T OK, T FAILED>
T checkLength(const ResponseApdu& apdu, const size_t size) {
if (apdu.dataSize() != size) {
LOG(ERROR) << "eSE response was the wrong length.";
return FAILED;
}
return OK;
}
/**
* Checks that the response APDU does no encode an error and that the amount of
* data matches the expected value.
*/
template<typename T, T OK, T FAILED>
T checkNoErrorAndLength(const ResponseApdu& apdu, const size_t size) {
if (apdu.isError()) {
LOG(ERROR) << "eSE operation failed";
return FAILED;
}
return checkLength<T, OK, FAILED>(apdu, size);
}
} // namespace android
} // namespace esed
} // namespace pn81a
#endif // ESED_PN81A_UTILS_H_