1/* 2 * Copyright (C) 2017 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#ifndef ESED_PN81A_UTILS_H_ 18#define ESED_PN81A_UTILS_H_ 19 20#include <functional> 21#include <string> 22 23#include <hidl/Status.h> 24 25#include <apdu/apdu.h> 26 27#include "pn81a.h" 28 29namespace android { 30namespace esed { 31namespace pn81a { 32 33// HIDL 34using ::android::hardware::Status; 35 36 37// libapdu 38using ::android::CommandApdu; 39using ResponseApdu = ::android::ResponseApdu<const std::vector<uint8_t>>; 40 41/** 42 * Reads a 32-bit integer from an iterator. 43 * @param first The first position to read from. 44 * @return A tuple of the value read and an iterator to one after the last position read from. 45 */ 46template<typename InputIt> 47std::tuple<uint32_t, InputIt> readBigEndianInt32(InputIt first) { 48 uint32_t ret; 49 auto it = first; 50 ret = *it++ << 24; 51 ret |= *it++ << 16; 52 ret |= *it++ << 8; 53 ret |= *it++; 54 return {ret, it}; 55} 56 57/** 58 * Writes a 32-bit integer to the iterator in big-endian format. 59 * @param value The value to write. 60 * @param first The first position in the iterator. 61 * @return An iterator to one after the last position written to. 62 */ 63template<typename OutputIt> 64OutputIt writeBigEndian(const uint32_t value, OutputIt first) { 65 auto it = first; 66 *it++ = 0xff & (value >> 24); 67 *it++ = 0xff & (value >> 16); 68 *it++ = 0xff & (value >> 8); 69 *it++ = 0xff & value; 70 return it; 71} 72 73/** 74 * Transceive a command with the eSE and perform common error checking. When the 75 * handler is called, it has been checked that the transmission to and reception 76 * from the eSE was successful and that the response is in a valid format. 77 */ 78template<typename T, T OK, T FAILED> 79T transceive(::android::esed::EseInterface& ese, const CommandApdu& command, 80 std::function<T(const ResponseApdu&)> handler = {}) { 81 // +1 for max size of extended response, +2 for status bytes 82 constexpr size_t MAX_RESPONSE_SIZE = std::numeric_limits<uint16_t>::max() + 1 + 2; 83 std::vector<uint8_t> responseBuffer(MAX_RESPONSE_SIZE); 84 const int ret = ese.transceive(command.vector(), responseBuffer); 85 86 // Check eSE communication was successful 87 if (ret < 0) { 88 std::string errMsg = "Failed to transceive data between AP and eSE"; 89 if (ese.error()) { 90 errMsg += " (" + std::to_string(ese.error_code()) + "): " + ese.error_message(); 91 } else { 92 errMsg += ": reason unknown"; 93 } 94 LOG(ERROR) << errMsg; 95 return FAILED; 96 } 97 const size_t recvd = static_cast<size_t>(ret); 98 99 // Need to recalculate the maximum response size if this fails 100 if (recvd > MAX_RESPONSE_SIZE) { 101 LOG(ERROR) << "eSE response was longer than the buffer, check the buffer size."; 102 return FAILED; 103 } 104 responseBuffer.resize(recvd); 105 106 // Check for ISO 7816-4 APDU response format errors 107 ResponseApdu apdu{responseBuffer}; 108 if (!apdu.ok()) { 109 LOG(ERROR) << "eSE response was invalid."; 110 return FAILED; 111 } 112 113 // Call handler if one was provided 114 if (handler) { 115 return handler(apdu); 116 } 117 118 return OK; 119} 120 121/** 122 * Checks that the amount of data in the response APDU matches the expected 123 * value. 124 */ 125template<typename T, T OK, T FAILED> 126T checkLength(const ResponseApdu& apdu, const size_t size) { 127 if (apdu.dataSize() != size) { 128 LOG(ERROR) << "eSE response was the wrong length."; 129 return FAILED; 130 } 131 return OK; 132} 133 134/** 135 * Checks that the response APDU does no encode an error and that the amount of 136 * data matches the expected value. 137 */ 138template<typename T, T OK, T FAILED> 139T checkNoErrorAndLength(const ResponseApdu& apdu, const size_t size) { 140 if (apdu.isError()) { 141 LOG(ERROR) << "eSE operation failed"; 142 return FAILED; 143 } 144 return checkLength<T, OK, FAILED>(apdu, size); 145} 146 147} // namespace android 148} // namespace esed 149} // namespace pn81a 150 151#endif // ESED_PN81A_UTILS_H_ 152