Andrew Scull | 1739842 | 2017-03-01 14:43:39 +0000 | [diff] [blame^] | 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.h" |
| 26 | #include "pn81a.h" |
| 27 | |
| 28 | namespace android { |
| 29 | namespace esed { |
| 30 | namespace pn81a { |
| 31 | |
| 32 | // HIDL |
| 33 | using ::android::hardware::Status; |
| 34 | |
| 35 | |
| 36 | // libapdu |
| 37 | using ::android::CommandApdu; |
| 38 | using ResponseApdu = ::android::ResponseApdu<const std::vector<uint8_t>>; |
| 39 | |
| 40 | /** |
| 41 | * Reads a 32-bit integer from an iterator. |
| 42 | * @param first The first position to read from. |
| 43 | * @return A tuple of the value read and an iterator to one after the last position read from. |
| 44 | */ |
| 45 | template<typename InputIt> |
| 46 | std::tuple<uint32_t, InputIt> readBigEndianInt32(InputIt first) { |
| 47 | uint32_t ret; |
| 48 | auto it = first; |
| 49 | ret = *it++ << 24; |
| 50 | ret |= *it++ << 16; |
| 51 | ret |= *it++ << 8; |
| 52 | ret |= *it++; |
| 53 | return {ret, it}; |
| 54 | } |
| 55 | |
| 56 | /** |
| 57 | * Writes a 32-bit integer to the iterator in big-endian format. |
| 58 | * @param value The value to write. |
| 59 | * @param first The first position in the iterator. |
| 60 | * @return An iterator to one after the last position written to. |
| 61 | */ |
| 62 | template<typename OutputIt> |
| 63 | OutputIt writeBigEndian(const uint32_t value, OutputIt first) { |
| 64 | auto it = first; |
| 65 | *it++ = 0xff & (value >> 24); |
| 66 | *it++ = 0xff & (value >> 16); |
| 67 | *it++ = 0xff & (value >> 8); |
| 68 | *it++ = 0xff & value; |
| 69 | return it; |
| 70 | } |
| 71 | |
| 72 | /** |
| 73 | * Transceive a command with the eSE and perform common error checking. When the |
| 74 | * handler is called, it has been checked that the transmission to and reception |
| 75 | * from the eSE was successful and that the response is in a valid format. |
| 76 | */ |
| 77 | template<typename T, T OK, T FAILED> |
| 78 | T transceive(::android::esed::EseInterface& ese, const CommandApdu& command, |
| 79 | std::function<T(const ResponseApdu&)> handler = {}) { |
| 80 | // +1 for max size of extended response, +2 for status bytes |
| 81 | constexpr size_t MAX_RESPONSE_SIZE = std::numeric_limits<uint16_t>::max() + 1 + 2; |
| 82 | std::vector<uint8_t> responseBuffer(MAX_RESPONSE_SIZE); |
| 83 | const int ret = ese.transceive(command.vector(), responseBuffer); |
| 84 | |
| 85 | // Check eSE communication was successful |
| 86 | if (ret < 0) { |
| 87 | std::string errMsg = "Failed to transceive data between AP and eSE"; |
| 88 | if (ese.error()) { |
| 89 | errMsg += " (" + std::to_string(ese.error_code()) + "): " + ese.error_message(); |
| 90 | } else { |
| 91 | errMsg += ": reason unknown"; |
| 92 | } |
| 93 | LOG(ERROR) << errMsg; |
| 94 | return FAILED; |
| 95 | } |
| 96 | const size_t recvd = static_cast<size_t>(ret); |
| 97 | |
| 98 | // Need to recalculate the maximum response size if this fails |
| 99 | if (recvd > MAX_RESPONSE_SIZE) { |
| 100 | LOG(ERROR) << "eSE response was longer than the buffer, check the buffer size."; |
| 101 | return FAILED; |
| 102 | } |
| 103 | responseBuffer.resize(recvd); |
| 104 | |
| 105 | // Check for ISO 7816-4 APDU response format errors |
| 106 | ResponseApdu apdu{responseBuffer}; |
| 107 | if (!apdu.ok()) { |
| 108 | LOG(ERROR) << "eSE response was invalid."; |
| 109 | return FAILED; |
| 110 | } |
| 111 | |
| 112 | // Call handler if one was provided |
| 113 | if (handler) { |
| 114 | return handler(apdu); |
| 115 | } |
| 116 | |
| 117 | return OK; |
| 118 | } |
| 119 | |
| 120 | /** |
| 121 | * Checks that the amount of data in the response APDU matches the expected |
| 122 | * value. |
| 123 | */ |
| 124 | template<typename T, T OK, T FAILED> |
| 125 | T checkLength(const ResponseApdu& apdu, const size_t size) { |
| 126 | if (apdu.dataSize() != size) { |
| 127 | LOG(ERROR) << "eSE response was the wrong length."; |
| 128 | return FAILED; |
| 129 | } |
| 130 | return OK; |
| 131 | } |
| 132 | |
| 133 | /** |
| 134 | * Checks that the response APDU does no encode an error and that the amount of |
| 135 | * data matches the expected value. |
| 136 | */ |
| 137 | template<typename T, T OK, T FAILED> |
| 138 | T checkNoErrorAndLength(const ResponseApdu& apdu, const size_t size) { |
| 139 | if (apdu.isError()) { |
| 140 | LOG(ERROR) << "eSE operation failed"; |
| 141 | return FAILED; |
| 142 | } |
| 143 | return checkLength<T, OK, FAILED>(apdu, size); |
| 144 | } |
| 145 | |
| 146 | } // namespace android |
| 147 | } // namespace esed |
| 148 | } // namespace pn81a |
| 149 | |
| 150 | #endif // ESED_PN81A_UTILS_H_ |