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1 | //----------------------------------------------------------------------------- | |
2 | // Frederik Möllers - August 2012 | |
3 | // | |
4 | // This code is licensed to you under the terms of the GNU GPL, version 2 or, | |
5 | // at your option, any later version. See the LICENSE.txt file for the text of | |
6 | // the license. | |
7 | //----------------------------------------------------------------------------- | |
8 | // Routines to support the German eletronic "Personalausweis" (ID card) | |
9 | // Note that the functions which do not implement USB commands do NOT initialize | |
10 | // the card (with iso14443a_select_card etc.). If You want to use these | |
11 | // functions, You need to do the setup before calling them! | |
12 | //----------------------------------------------------------------------------- | |
13 | ||
14 | #include "iso14443a.h" | |
15 | #include "epa.h" | |
16 | #include "cmd.h" | |
17 | ||
18 | // Protocol and Parameter Selection Request | |
19 | // use regular (1x) speed in both directions | |
20 | // CRC is already included | |
21 | static const uint8_t pps[] = {0xD0, 0x11, 0x00, 0x52, 0xA6}; | |
22 | ||
23 | // APDUs for communication with German Identification Card | |
24 | ||
25 | // General Authenticate (request encrypted nonce) WITHOUT the Le at the end | |
26 | static const uint8_t apdu_general_authenticate_pace_get_nonce[] = { | |
27 | 0x10, // CLA | |
28 | 0x86, // INS | |
29 | 0x00, // P1 | |
30 | 0x00, // P2 | |
31 | 0x02, // Lc | |
32 | 0x7C, // Type: Dynamic Authentication Data | |
33 | 0x00, // Length: 0 bytes | |
34 | }; | |
35 | ||
36 | // MSE: Set AT (only CLA, INS, P1 and P2) | |
37 | static const uint8_t apdu_mse_set_at_start[] = { | |
38 | 0x00, // CLA | |
39 | 0x22, // INS | |
40 | 0xC1, // P1 | |
41 | 0xA4, // P2 | |
42 | }; | |
43 | ||
44 | // SELECT BINARY with the ID for EF.CardAccess | |
45 | static const uint8_t apdu_select_binary_cardaccess[] = { | |
46 | 0x00, // CLA | |
47 | 0xA4, // INS | |
48 | 0x02, // P1 | |
49 | 0x0C, // P2 | |
50 | 0x02, // Lc | |
51 | 0x01, // ID | |
52 | 0x1C // ID | |
53 | }; | |
54 | ||
55 | // READ BINARY | |
56 | static const uint8_t apdu_read_binary[] = { | |
57 | 0x00, // CLA | |
58 | 0xB0, // INS | |
59 | 0x00, // P1 | |
60 | 0x00, // P2 | |
61 | 0x38 // Le | |
62 | }; | |
63 | ||
64 | ||
65 | // the leading bytes of a PACE OID | |
66 | static const uint8_t oid_pace_start[] = { | |
67 | 0x04, // itu-t, identified-organization | |
68 | 0x00, // etsi | |
69 | 0x7F, // reserved | |
70 | 0x00, // etsi-identified-organization | |
71 | 0x07, // bsi-de | |
72 | 0x02, // protocols | |
73 | 0x02, // smartcard | |
74 | 0x04 // id-PACE | |
75 | }; | |
76 | ||
77 | //----------------------------------------------------------------------------- | |
78 | // Closes the communication channel and turns off the field | |
79 | //----------------------------------------------------------------------------- | |
80 | void EPA_Finish() | |
81 | { | |
82 | FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); | |
83 | LEDsoff(); | |
84 | } | |
85 | ||
86 | //----------------------------------------------------------------------------- | |
87 | // Parses DER encoded data, e.g. from EF.CardAccess and fills out the given | |
88 | // structs. If a pointer is 0, it is ignored. | |
89 | // The function returns 0 on success and if an error occured, it returns the | |
90 | // offset where it occured. | |
91 | // | |
92 | // TODO: This function can access memory outside of the given data if the DER | |
93 | // encoding is broken | |
94 | // TODO: Support skipping elements with a length > 0x7F | |
95 | // TODO: Support OIDs with a length > 7F | |
96 | // TODO: Support elements with long tags (tag is longer than 1 byte) | |
97 | // TODO: Support proprietary PACE domain parameters | |
98 | //----------------------------------------------------------------------------- | |
99 | size_t EPA_Parse_CardAccess(uint8_t *data, | |
100 | size_t length, | |
101 | pace_version_info_t *pace_info) | |
102 | { | |
103 | size_t index = 0; | |
104 | ||
105 | while (index <= length - 2) { | |
106 | // determine type of element | |
107 | // SET or SEQUENCE | |
108 | if (data[index] == 0x31 || data[index] == 0x30) { | |
109 | // enter the set (skip tag + length) | |
110 | index += 2; | |
111 | // check for extended length | |
112 | if ((data[index - 1] & 0x80) != 0) { | |
113 | index += (data[index-1] & 0x7F); | |
114 | } | |
115 | } | |
116 | // OID | |
117 | else if (data[index] == 0x06) { | |
118 | // is this a PACE OID? | |
119 | if (data[index + 1] == 0x0A // length matches | |
120 | && memcmp(data + index + 2, | |
121 | oid_pace_start, | |
122 | sizeof(oid_pace_start)) == 0 // content matches | |
123 | && pace_info != NULL) | |
124 | { | |
125 | // first, clear the pace_info struct | |
126 | memset(pace_info, 0, sizeof(pace_version_info_t)); | |
127 | memcpy(pace_info->oid, data + index + 2, sizeof(pace_info->oid)); | |
128 | // a PACE OID is followed by the version | |
129 | index += data[index + 1] + 2; | |
130 | if (data[index] == 02 && data[index + 1] == 01) { | |
131 | pace_info->version = data[index + 2]; | |
132 | index += 3; | |
133 | } | |
134 | else { | |
135 | return index; | |
136 | } | |
137 | // after that there might(!) be the parameter ID | |
138 | if (data[index] == 02 && data[index + 1] == 01) { | |
139 | pace_info->parameter_id = data[index + 2]; | |
140 | index += 3; | |
141 | } | |
142 | } | |
143 | else { | |
144 | // skip this OID | |
145 | index += 2 + data[index + 1]; | |
146 | } | |
147 | } | |
148 | // if the length is 0, something is wrong | |
149 | // TODO: This needs to be extended to support long tags | |
150 | else if (data[index + 1] == 0) { | |
151 | return index; | |
152 | } | |
153 | else { | |
154 | // skip this part | |
155 | // TODO: This needs to be extended to support long tags | |
156 | // TODO: This needs to be extended to support unknown elements with | |
157 | // a size > 0x7F | |
158 | index += 2 + data[index + 1]; | |
159 | } | |
160 | } | |
161 | ||
162 | // TODO: We should check whether we reached the end in error, but for that | |
163 | // we need a better parser (e.g. with states like IN_SET or IN_PACE_INFO) | |
164 | return 0; | |
165 | } | |
166 | ||
167 | //----------------------------------------------------------------------------- | |
168 | // Read the file EF.CardAccess and save it into a buffer (at most max_length bytes) | |
169 | // Returns -1 on failure or the length of the data on success | |
170 | // TODO: for the moment this sends only 1 APDU regardless of the requested length | |
171 | //----------------------------------------------------------------------------- | |
172 | int EPA_Read_CardAccess(uint8_t *buffer, size_t max_length) | |
173 | { | |
174 | // the response APDU of the card | |
175 | // since the card doesn't always care for the expected length we send it, | |
176 | // we reserve 262 bytes here just to be safe (256-byte APDU + SW + ISO frame) | |
177 | uint8_t response_apdu[262]; | |
178 | int rapdu_length = 0; | |
179 | ||
180 | // select the file EF.CardAccess | |
181 | rapdu_length = iso14_apdu((uint8_t *)apdu_select_binary_cardaccess, | |
182 | sizeof(apdu_select_binary_cardaccess), | |
183 | response_apdu); | |
184 | if (rapdu_length != 6 | |
185 | || response_apdu[rapdu_length - 4] != 0x90 | |
186 | || response_apdu[rapdu_length - 3] != 0x00) | |
187 | { | |
188 | return -1; | |
189 | } | |
190 | ||
191 | // read the file | |
192 | rapdu_length = iso14_apdu((uint8_t *)apdu_read_binary, | |
193 | sizeof(apdu_read_binary), | |
194 | response_apdu); | |
195 | if (rapdu_length <= 6 | |
196 | || response_apdu[rapdu_length - 4] != 0x90 | |
197 | || response_apdu[rapdu_length - 3] != 0x00) | |
198 | { | |
199 | return -1; | |
200 | } | |
201 | ||
202 | // copy the content into the buffer | |
203 | // length of data available: apdu_length - 4 (ISO frame) - 2 (SW) | |
204 | size_t to_copy = rapdu_length - 6; | |
205 | to_copy = to_copy < max_length ? to_copy : max_length; | |
206 | memcpy(buffer, response_apdu+2, to_copy); | |
207 | return to_copy; | |
208 | } | |
209 | ||
210 | //----------------------------------------------------------------------------- | |
211 | // Abort helper function for EPA_PACE_Collect_Nonce | |
212 | // sets relevant data in ack, sends the response | |
213 | //----------------------------------------------------------------------------- | |
214 | static void EPA_PACE_Collect_Nonce_Abort(uint8_t step, int func_return) | |
215 | { | |
216 | // // step in which the failure occured | |
217 | // ack->arg[0] = step; | |
218 | // // last return code | |
219 | // ack->arg[1] = func_return; | |
220 | ||
221 | // power down the field | |
222 | EPA_Finish(); | |
223 | ||
224 | // send the USB packet | |
225 | cmd_send(CMD_ACK,step,func_return,0,0,0); | |
226 | //UsbSendPacket((void *)ack, sizeof(UsbCommand)); | |
227 | } | |
228 | ||
229 | //----------------------------------------------------------------------------- | |
230 | // Acquire one encrypted PACE nonce | |
231 | //----------------------------------------------------------------------------- | |
232 | void EPA_PACE_Collect_Nonce(UsbCommand *c) | |
233 | { | |
234 | /* | |
235 | * ack layout: | |
236 | * arg: | |
237 | * 1. element | |
238 | * step where the error occured or 0 if no error occured | |
239 | * 2. element | |
240 | * return code of the last executed function | |
241 | * d: | |
242 | * Encrypted nonce | |
243 | */ | |
244 | ||
245 | // return value of a function | |
246 | int func_return; | |
247 | ||
248 | // // initialize ack with 0s | |
249 | // memset(ack->arg, 0, 12); | |
250 | // memset(ack->d.asBytes, 0, 48); | |
251 | ||
252 | // set up communication | |
253 | func_return = EPA_Setup(); | |
254 | if (func_return != 0) { | |
255 | EPA_PACE_Collect_Nonce_Abort(1, func_return); | |
256 | return; | |
257 | } | |
258 | ||
259 | // increase the timeout (at least some cards really do need this!) | |
260 | iso14a_set_timeout(0x0002FFFF); | |
261 | ||
262 | // read the CardAccess file | |
263 | // this array will hold the CardAccess file | |
264 | uint8_t card_access[256] = {0}; | |
265 | int card_access_length = EPA_Read_CardAccess(card_access, 256); | |
266 | // the response has to be at least this big to hold the OID | |
267 | if (card_access_length < 18) { | |
268 | EPA_PACE_Collect_Nonce_Abort(2, card_access_length); | |
269 | return; | |
270 | } | |
271 | ||
272 | // this will hold the PACE info of the card | |
273 | pace_version_info_t pace_version_info; | |
274 | // search for the PACE OID | |
275 | func_return = EPA_Parse_CardAccess(card_access, | |
276 | card_access_length, | |
277 | &pace_version_info); | |
278 | if (func_return != 0 || pace_version_info.version == 0) { | |
279 | EPA_PACE_Collect_Nonce_Abort(3, func_return); | |
280 | return; | |
281 | } | |
282 | ||
283 | // initiate the PACE protocol | |
284 | // use the CAN for the password since that doesn't change | |
285 | func_return = EPA_PACE_MSE_Set_AT(pace_version_info, 2); | |
286 | ||
287 | // now get the nonce | |
288 | uint8_t nonce[256] = {0}; | |
289 | uint8_t requested_size = (uint8_t)c->arg[0]; | |
290 | func_return = EPA_PACE_Get_Nonce(requested_size, nonce); | |
291 | // check if the command succeeded | |
292 | if (func_return < 0) | |
293 | { | |
294 | EPA_PACE_Collect_Nonce_Abort(4, func_return); | |
295 | return; | |
296 | } | |
297 | ||
298 | // all done, return | |
299 | EPA_Finish(); | |
300 | ||
301 | // save received information | |
302 | // ack->arg[1] = func_return; | |
303 | // memcpy(ack->d.asBytes, nonce, func_return); | |
304 | // UsbSendPacket((void *)ack, sizeof(UsbCommand)); | |
305 | cmd_send(CMD_ACK,0,func_return,0,nonce,func_return); | |
306 | } | |
307 | ||
308 | //----------------------------------------------------------------------------- | |
309 | // Performs the "Get Nonce" step of the PACE protocol and saves the returned | |
310 | // nonce. The caller is responsible for allocating enough memory to store the | |
311 | // nonce. Note that the returned size might be less or than or greater than the | |
312 | // requested size! | |
313 | // Returns the actual size of the nonce on success or a less-than-zero error | |
314 | // code on failure. | |
315 | //----------------------------------------------------------------------------- | |
316 | int EPA_PACE_Get_Nonce(uint8_t requested_length, uint8_t *nonce) | |
317 | { | |
318 | // build the APDU | |
319 | uint8_t apdu[sizeof(apdu_general_authenticate_pace_get_nonce) + 1]; | |
320 | // copy the constant part | |
321 | memcpy(apdu, | |
322 | apdu_general_authenticate_pace_get_nonce, | |
323 | sizeof(apdu_general_authenticate_pace_get_nonce)); | |
324 | // append Le (requested length + 2 due to tag/length taking 2 bytes) in RAPDU | |
325 | apdu[sizeof(apdu_general_authenticate_pace_get_nonce)] = requested_length + 4; | |
326 | ||
327 | // send it | |
328 | uint8_t response_apdu[262]; | |
329 | int send_return = iso14_apdu(apdu, | |
330 | sizeof(apdu), | |
331 | response_apdu); | |
332 | // check if the command succeeded | |
333 | if (send_return < 6 | |
334 | || response_apdu[send_return - 4] != 0x90 | |
335 | || response_apdu[send_return - 3] != 0x00) | |
336 | { | |
337 | return -1; | |
338 | } | |
339 | ||
340 | // if there is no nonce in the RAPDU, return here | |
341 | if (send_return < 10) | |
342 | { | |
343 | // no error | |
344 | return 0; | |
345 | } | |
346 | // get the actual length of the nonce | |
347 | uint8_t nonce_length = response_apdu[5]; | |
348 | if (nonce_length > send_return - 10) | |
349 | { | |
350 | nonce_length = send_return - 10; | |
351 | } | |
352 | // copy the nonce | |
353 | memcpy(nonce, response_apdu + 6, nonce_length); | |
354 | ||
355 | return nonce_length; | |
356 | } | |
357 | ||
358 | //----------------------------------------------------------------------------- | |
359 | // Initializes the PACE protocol by performing the "MSE: Set AT" step | |
360 | // Returns 0 on success or a non-zero error code on failure | |
361 | //----------------------------------------------------------------------------- | |
362 | int EPA_PACE_MSE_Set_AT(pace_version_info_t pace_version_info, uint8_t password) | |
363 | { | |
364 | // create the MSE: Set AT APDU | |
365 | uint8_t apdu[23]; | |
366 | // the minimum length (will be increased as more data is added) | |
367 | size_t apdu_length = 20; | |
368 | // copy the constant part | |
369 | memcpy(apdu, | |
370 | apdu_mse_set_at_start, | |
371 | sizeof(apdu_mse_set_at_start)); | |
372 | // type: OID | |
373 | apdu[5] = 0x80; | |
374 | // length of the OID | |
375 | apdu[6] = sizeof(pace_version_info.oid); | |
376 | // copy the OID | |
377 | memcpy(apdu + 7, | |
378 | pace_version_info.oid, | |
379 | sizeof(pace_version_info.oid)); | |
380 | // type: password | |
381 | apdu[17] = 0x83; | |
382 | // length: 1 | |
383 | apdu[18] = 1; | |
384 | // password | |
385 | apdu[19] = password; | |
386 | // if standardized domain parameters are used, copy the ID | |
387 | if (pace_version_info.parameter_id != 0) { | |
388 | apdu_length += 3; | |
389 | // type: domain parameter | |
390 | apdu[20] = 0x84; | |
391 | // length: 1 | |
392 | apdu[21] = 1; | |
393 | // copy the parameter ID | |
394 | apdu[22] = pace_version_info.parameter_id; | |
395 | } | |
396 | // now set Lc to the actual length | |
397 | apdu[4] = apdu_length - 5; | |
398 | // send it | |
399 | uint8_t response_apdu[6]; | |
400 | int send_return = iso14_apdu(apdu, | |
401 | apdu_length, | |
402 | response_apdu); | |
403 | // check if the command succeeded | |
404 | if (send_return != 6 | |
405 | || response_apdu[send_return - 4] != 0x90 | |
406 | || response_apdu[send_return - 3] != 0x00) | |
407 | { | |
408 | return 1; | |
409 | } | |
410 | return 0; | |
411 | } | |
412 | ||
413 | //----------------------------------------------------------------------------- | |
414 | // Set up a communication channel (Card Select, PPS) | |
415 | // Returns 0 on success or a non-zero error code on failure | |
416 | //----------------------------------------------------------------------------- | |
417 | int EPA_Setup() | |
418 | { | |
419 | // return code | |
420 | int return_code = 0; | |
421 | // card UID | |
422 | uint8_t uid[10]; | |
423 | // card select information | |
424 | iso14a_card_select_t card_select_info; | |
425 | // power up the field | |
426 | iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD); | |
427 | ||
428 | // select the card | |
429 | return_code = iso14443a_select_card(uid, &card_select_info, NULL); | |
430 | if (return_code != 1) { | |
431 | return 1; | |
432 | } | |
433 | ||
434 | // send the PPS request | |
435 | ReaderTransmit((uint8_t *)pps, sizeof(pps), NULL); | |
436 | uint8_t pps_response[3]; | |
437 | uint8_t pps_response_par[1]; | |
438 | return_code = ReaderReceive(pps_response, pps_response_par); | |
439 | if (return_code != 3 || pps_response[0] != 0xD0) { | |
440 | return return_code == 0 ? 2 : return_code; | |
441 | } | |
442 | ||
443 | return 0; | |
444 | } |