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