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5acd09bd 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//-----------------------------------------------------------------------------
3bb07d96 8// Routines to support the German electronic "Personalausweis" (ID card)
5acd09bd 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"
4be27083 15#include "iso14443b.h"
5acd09bd 16#include "epa.h"
902cb3c0 17#include "cmd.h"
5acd09bd 18
4be27083 19// Protocol and Parameter Selection Request for ISO 14443 type A cards
5acd09bd 20// use regular (1x) speed in both directions
21// CRC is already included
22static const uint8_t pps[] = {0xD0, 0x11, 0x00, 0x52, 0xA6};
23
24// APDUs for communication with German Identification Card
25
26// General Authenticate (request encrypted nonce) WITHOUT the Le at the end
27static const uint8_t apdu_general_authenticate_pace_get_nonce[] = {
28 0x10, // CLA
29 0x86, // INS
30 0x00, // P1
31 0x00, // P2
32 0x02, // Lc
33 0x7C, // Type: Dynamic Authentication Data
34 0x00, // Length: 0 bytes
35};
36
37// MSE: Set AT (only CLA, INS, P1 and P2)
38static const uint8_t apdu_mse_set_at_start[] = {
39 0x00, // CLA
40 0x22, // INS
41 0xC1, // P1
42 0xA4, // P2
43};
44
45// SELECT BINARY with the ID for EF.CardAccess
46static const uint8_t apdu_select_binary_cardaccess[] = {
47 0x00, // CLA
48 0xA4, // INS
49 0x02, // P1
50 0x0C, // P2
51 0x02, // Lc
52 0x01, // ID
53 0x1C // ID
54};
55
56// READ BINARY
57static const uint8_t apdu_read_binary[] = {
58 0x00, // CLA
59 0xB0, // INS
60 0x00, // P1
61 0x00, // P2
62 0x38 // Le
63};
64
65
66// the leading bytes of a PACE OID
67static const uint8_t oid_pace_start[] = {
68 0x04, // itu-t, identified-organization
69 0x00, // etsi
70 0x7F, // reserved
71 0x00, // etsi-identified-organization
72 0x07, // bsi-de
73 0x02, // protocols
74 0x02, // smartcard
75 0x04 // id-PACE
76};
77
3bb07d96
FM
78// APDUs for replaying:
79// MSE: Set AT (initiate PACE)
80static uint8_t apdu_replay_mse_set_at_pace[41];
81// General Authenticate (Get Nonce)
82static uint8_t apdu_replay_general_authenticate_pace_get_nonce[8];
83// General Authenticate (Map Nonce)
84static uint8_t apdu_replay_general_authenticate_pace_map_nonce[75];
85// General Authenticate (Mutual Authenticate)
86static uint8_t apdu_replay_general_authenticate_pace_mutual_authenticate[75];
87// General Authenticate (Perform Key Agreement)
88static uint8_t apdu_replay_general_authenticate_pace_perform_key_agreement[18];
89// pointers to the APDUs (for iterations)
90static struct {
91 uint8_t len;
92 uint8_t *data;
93} const apdus_replay[] = {
94 {sizeof(apdu_replay_mse_set_at_pace), apdu_replay_mse_set_at_pace},
95 {sizeof(apdu_replay_general_authenticate_pace_get_nonce), apdu_replay_general_authenticate_pace_get_nonce},
96 {sizeof(apdu_replay_general_authenticate_pace_map_nonce), apdu_replay_general_authenticate_pace_map_nonce},
97 {sizeof(apdu_replay_general_authenticate_pace_mutual_authenticate), apdu_replay_general_authenticate_pace_mutual_authenticate},
98 {sizeof(apdu_replay_general_authenticate_pace_perform_key_agreement), apdu_replay_general_authenticate_pace_perform_key_agreement}
99};
100
101// lengths of the replay APDUs
102static uint8_t apdu_lengths_replay[5];
103
4be27083
FM
104// type of card (ISO 14443 A or B)
105static char iso_type = 0;
106
107//-----------------------------------------------------------------------------
108// Wrapper for sending APDUs to type A and B cards
109//-----------------------------------------------------------------------------
110int EPA_APDU(uint8_t *apdu, size_t length, uint8_t *response)
111{
112 switch(iso_type)
113 {
114 case 'a':
115 return iso14_apdu(apdu, (uint16_t) length, response);
116 break;
117 case 'b':
118 return iso14443b_apdu(apdu, length, response);
119 break;
120 default:
121 return 0;
122 break;
123 }
124}
125
5acd09bd 126//-----------------------------------------------------------------------------
127// Closes the communication channel and turns off the field
128//-----------------------------------------------------------------------------
129void EPA_Finish()
130{
131 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
132 LEDsoff();
4be27083 133 iso_type = 0;
5acd09bd 134}
135
136//-----------------------------------------------------------------------------
137// Parses DER encoded data, e.g. from EF.CardAccess and fills out the given
138// structs. If a pointer is 0, it is ignored.
139// The function returns 0 on success and if an error occured, it returns the
140// offset where it occured.
141//
142// TODO: This function can access memory outside of the given data if the DER
143// encoding is broken
144// TODO: Support skipping elements with a length > 0x7F
145// TODO: Support OIDs with a length > 7F
146// TODO: Support elements with long tags (tag is longer than 1 byte)
147// TODO: Support proprietary PACE domain parameters
148//-----------------------------------------------------------------------------
149size_t EPA_Parse_CardAccess(uint8_t *data,
150 size_t length,
151 pace_version_info_t *pace_info)
152{
153 size_t index = 0;
3bb07d96 154
5acd09bd 155 while (index <= length - 2) {
156 // determine type of element
157 // SET or SEQUENCE
158 if (data[index] == 0x31 || data[index] == 0x30) {
159 // enter the set (skip tag + length)
160 index += 2;
57642f63 161 // check for extended length
5acd09bd 162 if ((data[index - 1] & 0x80) != 0) {
57642f63 163 index += (data[index-1] & 0x7F);
5acd09bd 164 }
165 }
166 // OID
167 else if (data[index] == 0x06) {
168 // is this a PACE OID?
169 if (data[index + 1] == 0x0A // length matches
170 && memcmp(data + index + 2,
171 oid_pace_start,
172 sizeof(oid_pace_start)) == 0 // content matches
173 && pace_info != NULL)
174 {
175 // first, clear the pace_info struct
176 memset(pace_info, 0, sizeof(pace_version_info_t));
177 memcpy(pace_info->oid, data + index + 2, sizeof(pace_info->oid));
178 // a PACE OID is followed by the version
179 index += data[index + 1] + 2;
180 if (data[index] == 02 && data[index + 1] == 01) {
181 pace_info->version = data[index + 2];
182 index += 3;
183 }
184 else {
185 return index;
186 }
187 // after that there might(!) be the parameter ID
188 if (data[index] == 02 && data[index + 1] == 01) {
189 pace_info->parameter_id = data[index + 2];
190 index += 3;
191 }
192 }
193 else {
194 // skip this OID
195 index += 2 + data[index + 1];
196 }
197 }
198 // if the length is 0, something is wrong
199 // TODO: This needs to be extended to support long tags
200 else if (data[index + 1] == 0) {
201 return index;
202 }
203 else {
204 // skip this part
205 // TODO: This needs to be extended to support long tags
206 // TODO: This needs to be extended to support unknown elements with
207 // a size > 0x7F
208 index += 2 + data[index + 1];
209 }
210 }
3bb07d96 211
5acd09bd 212 // TODO: We should check whether we reached the end in error, but for that
213 // we need a better parser (e.g. with states like IN_SET or IN_PACE_INFO)
214 return 0;
215}
216
217//-----------------------------------------------------------------------------
218// Read the file EF.CardAccess and save it into a buffer (at most max_length bytes)
219// Returns -1 on failure or the length of the data on success
220// TODO: for the moment this sends only 1 APDU regardless of the requested length
221//-----------------------------------------------------------------------------
222int EPA_Read_CardAccess(uint8_t *buffer, size_t max_length)
223{
224 // the response APDU of the card
225 // since the card doesn't always care for the expected length we send it,
226 // we reserve 262 bytes here just to be safe (256-byte APDU + SW + ISO frame)
227 uint8_t response_apdu[262];
228 int rapdu_length = 0;
3bb07d96 229
5acd09bd 230 // select the file EF.CardAccess
4be27083 231 rapdu_length = EPA_APDU((uint8_t *)apdu_select_binary_cardaccess,
5acd09bd 232 sizeof(apdu_select_binary_cardaccess),
233 response_apdu);
4be27083 234 if (rapdu_length < 6
5acd09bd 235 || response_apdu[rapdu_length - 4] != 0x90
236 || response_apdu[rapdu_length - 3] != 0x00)
237 {
4be27083 238 DbpString("Failed to select EF.CardAccess!");
5acd09bd 239 return -1;
240 }
3bb07d96 241
5acd09bd 242 // read the file
4be27083 243 rapdu_length = EPA_APDU((uint8_t *)apdu_read_binary,
5acd09bd 244 sizeof(apdu_read_binary),
245 response_apdu);
246 if (rapdu_length <= 6
247 || response_apdu[rapdu_length - 4] != 0x90
248 || response_apdu[rapdu_length - 3] != 0x00)
249 {
4be27083 250 Dbprintf("Failed to read EF.CardAccess!");
5acd09bd 251 return -1;
252 }
3bb07d96 253
5acd09bd 254 // copy the content into the buffer
255 // length of data available: apdu_length - 4 (ISO frame) - 2 (SW)
256 size_t to_copy = rapdu_length - 6;
257 to_copy = to_copy < max_length ? to_copy : max_length;
258 memcpy(buffer, response_apdu+2, to_copy);
259 return to_copy;
260}
261
262//-----------------------------------------------------------------------------
263// Abort helper function for EPA_PACE_Collect_Nonce
264// sets relevant data in ack, sends the response
265//-----------------------------------------------------------------------------
902cb3c0 266static void EPA_PACE_Collect_Nonce_Abort(uint8_t step, int func_return)
5acd09bd 267{
5acd09bd 268 // power down the field
269 EPA_Finish();
3bb07d96 270
e5ad43c0 271 // send the USB packet
3bb07d96 272 cmd_send(CMD_ACK,step,func_return,0,0,0);
5acd09bd 273}
274
275//-----------------------------------------------------------------------------
276// Acquire one encrypted PACE nonce
277//-----------------------------------------------------------------------------
902cb3c0 278void EPA_PACE_Collect_Nonce(UsbCommand *c)
5acd09bd 279{
280 /*
281 * ack layout:
282 * arg:
283 * 1. element
284 * step where the error occured or 0 if no error occured
285 * 2. element
286 * return code of the last executed function
287 * d:
288 * Encrypted nonce
289 */
290
291 // return value of a function
3fe4ff4f 292 int func_return = 0;
5acd09bd 293
5acd09bd 294 // set up communication
295 func_return = EPA_Setup();
296 if (func_return != 0) {
902cb3c0 297 EPA_PACE_Collect_Nonce_Abort(1, func_return);
5acd09bd 298 return;
299 }
300
5acd09bd 301 // read the CardAccess file
302 // this array will hold the CardAccess file
303 uint8_t card_access[256] = {0};
304 int card_access_length = EPA_Read_CardAccess(card_access, 256);
305 // the response has to be at least this big to hold the OID
306 if (card_access_length < 18) {
902cb3c0 307 EPA_PACE_Collect_Nonce_Abort(2, card_access_length);
5acd09bd 308 return;
309 }
310
311 // this will hold the PACE info of the card
312 pace_version_info_t pace_version_info;
313 // search for the PACE OID
314 func_return = EPA_Parse_CardAccess(card_access,
315 card_access_length,
316 &pace_version_info);
317 if (func_return != 0 || pace_version_info.version == 0) {
902cb3c0 318 EPA_PACE_Collect_Nonce_Abort(3, func_return);
5acd09bd 319 return;
320 }
3bb07d96 321
5acd09bd 322 // initiate the PACE protocol
323 // use the CAN for the password since that doesn't change
324 func_return = EPA_PACE_MSE_Set_AT(pace_version_info, 2);
3bb07d96 325
5acd09bd 326 // now get the nonce
327 uint8_t nonce[256] = {0};
328 uint8_t requested_size = (uint8_t)c->arg[0];
329 func_return = EPA_PACE_Get_Nonce(requested_size, nonce);
330 // check if the command succeeded
331 if (func_return < 0)
332 {
902cb3c0 333 EPA_PACE_Collect_Nonce_Abort(4, func_return);
5acd09bd 334 return;
335 }
3bb07d96
FM
336
337 // all done, return
902cb3c0 338 EPA_Finish();
3bb07d96 339
5acd09bd 340 // save received information
3bb07d96 341 cmd_send(CMD_ACK,0,func_return,0,nonce,func_return);
5acd09bd 342}
343
344//-----------------------------------------------------------------------------
345// Performs the "Get Nonce" step of the PACE protocol and saves the returned
346// nonce. The caller is responsible for allocating enough memory to store the
347// nonce. Note that the returned size might be less or than or greater than the
348// requested size!
349// Returns the actual size of the nonce on success or a less-than-zero error
350// code on failure.
351//-----------------------------------------------------------------------------
352int EPA_PACE_Get_Nonce(uint8_t requested_length, uint8_t *nonce)
353{
354 // build the APDU
355 uint8_t apdu[sizeof(apdu_general_authenticate_pace_get_nonce) + 1];
356 // copy the constant part
357 memcpy(apdu,
358 apdu_general_authenticate_pace_get_nonce,
359 sizeof(apdu_general_authenticate_pace_get_nonce));
360 // append Le (requested length + 2 due to tag/length taking 2 bytes) in RAPDU
361 apdu[sizeof(apdu_general_authenticate_pace_get_nonce)] = requested_length + 4;
3bb07d96 362
5acd09bd 363 // send it
364 uint8_t response_apdu[262];
4be27083 365 int send_return = EPA_APDU(apdu,
5acd09bd 366 sizeof(apdu),
367 response_apdu);
368 // check if the command succeeded
369 if (send_return < 6
370 || response_apdu[send_return - 4] != 0x90
371 || response_apdu[send_return - 3] != 0x00)
372 {
373 return -1;
374 }
3bb07d96 375
5acd09bd 376 // if there is no nonce in the RAPDU, return here
377 if (send_return < 10)
378 {
379 // no error
380 return 0;
381 }
382 // get the actual length of the nonce
383 uint8_t nonce_length = response_apdu[5];
384 if (nonce_length > send_return - 10)
385 {
386 nonce_length = send_return - 10;
387 }
388 // copy the nonce
389 memcpy(nonce, response_apdu + 6, nonce_length);
3bb07d96 390
5acd09bd 391 return nonce_length;
392}
393
394//-----------------------------------------------------------------------------
395// Initializes the PACE protocol by performing the "MSE: Set AT" step
396// Returns 0 on success or a non-zero error code on failure
397//-----------------------------------------------------------------------------
398int EPA_PACE_MSE_Set_AT(pace_version_info_t pace_version_info, uint8_t password)
399{
400 // create the MSE: Set AT APDU
401 uint8_t apdu[23];
402 // the minimum length (will be increased as more data is added)
403 size_t apdu_length = 20;
404 // copy the constant part
405 memcpy(apdu,
406 apdu_mse_set_at_start,
407 sizeof(apdu_mse_set_at_start));
408 // type: OID
409 apdu[5] = 0x80;
410 // length of the OID
411 apdu[6] = sizeof(pace_version_info.oid);
412 // copy the OID
413 memcpy(apdu + 7,
414 pace_version_info.oid,
415 sizeof(pace_version_info.oid));
416 // type: password
417 apdu[17] = 0x83;
418 // length: 1
419 apdu[18] = 1;
420 // password
421 apdu[19] = password;
422 // if standardized domain parameters are used, copy the ID
423 if (pace_version_info.parameter_id != 0) {
424 apdu_length += 3;
425 // type: domain parameter
426 apdu[20] = 0x84;
427 // length: 1
428 apdu[21] = 1;
429 // copy the parameter ID
430 apdu[22] = pace_version_info.parameter_id;
431 }
432 // now set Lc to the actual length
433 apdu[4] = apdu_length - 5;
434 // send it
435 uint8_t response_apdu[6];
4be27083 436 int send_return = EPA_APDU(apdu,
5acd09bd 437 apdu_length,
438 response_apdu);
439 // check if the command succeeded
440 if (send_return != 6
441 || response_apdu[send_return - 4] != 0x90
442 || response_apdu[send_return - 3] != 0x00)
443 {
444 return 1;
445 }
446 return 0;
447}
448
3bb07d96
FM
449//-----------------------------------------------------------------------------
450// Perform the PACE protocol by replaying given APDUs
451//-----------------------------------------------------------------------------
452void EPA_PACE_Replay(UsbCommand *c)
453{
454 uint32_t timings[sizeof(apdu_lengths_replay) / sizeof(apdu_lengths_replay[0])] = {0};
455
456 // if an APDU has been passed, save it
457 if (c->arg[0] != 0) {
458 // make sure it's not too big
459 if(c->arg[2] > apdus_replay[c->arg[0] - 1].len)
460 {
461 cmd_send(CMD_ACK, 1, 0, 0, NULL, 0);
462 }
463 memcpy(apdus_replay[c->arg[0] - 1].data + c->arg[1],
464 c->d.asBytes,
465 c->arg[2]);
466 // save/update APDU length
467 if (c->arg[1] == 0) {
468 apdu_lengths_replay[c->arg[0] - 1] = c->arg[2];
469 } else {
470 apdu_lengths_replay[c->arg[0] - 1] += c->arg[2];
471 }
472 cmd_send(CMD_ACK, 0, 0, 0, NULL, 0);
473 return;
474 }
475
476 // return value of a function
477 int func_return;
478
479 // set up communication
480 func_return = EPA_Setup();
481 if (func_return != 0) {
482 EPA_Finish();
483 cmd_send(CMD_ACK, 2, func_return, 0, NULL, 0);
484 return;
485 }
486
3bb07d96
FM
487 // response APDU
488 uint8_t response_apdu[300] = {0};
489
490 // now replay the data and measure the timings
491 for (int i = 0; i < sizeof(apdu_lengths_replay); i++) {
492 StartCountUS();
4be27083 493 func_return = EPA_APDU(apdus_replay[i].data,
3bb07d96
FM
494 apdu_lengths_replay[i],
495 response_apdu);
496 timings[i] = GetCountUS();
497 // every step but the last one should succeed
498 if (i < sizeof(apdu_lengths_replay) - 1
499 && (func_return < 6
500 || response_apdu[func_return - 4] != 0x90
501 || response_apdu[func_return - 3] != 0x00))
502 {
503 EPA_Finish();
504 cmd_send(CMD_ACK, 3 + i, func_return, 0, timings, 20);
505 return;
506 }
507 }
508 EPA_Finish();
509 cmd_send(CMD_ACK,0,0,0,timings,20);
510 return;
511}
512
5acd09bd 513//-----------------------------------------------------------------------------
514// Set up a communication channel (Card Select, PPS)
515// Returns 0 on success or a non-zero error code on failure
516//-----------------------------------------------------------------------------
517int EPA_Setup()
518{
5acd09bd 519 int return_code = 0;
2ed270a8 520 uint8_t uid[10];
3fe4ff4f 521 uint8_t pps_response[3];
522 uint8_t pps_response_par[1];
5acd09bd 523 iso14a_card_select_t card_select_info;
3fe4ff4f 524
4be27083 525 // first, look for type A cards
5acd09bd 526 // power up the field
7bc95e2e 527 iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD);
5acd09bd 528 // select the card
529 return_code = iso14443a_select_card(uid, &card_select_info, NULL);
4be27083
FM
530 if (return_code == 1) {
531 // send the PPS request
532 ReaderTransmit((uint8_t *)pps, sizeof(pps), NULL);
533 return_code = ReaderReceive(pps_response, pps_response_par);
534 if (return_code != 3 || pps_response[0] != 0xD0) {
535 return return_code == 0 ? 2 : return_code;
536 }
537 Dbprintf("ISO 14443 Type A");
538 iso_type = 'a';
539 return 0;
5acd09bd 540 }
4be27083
FM
541
542 // if we're here, there is no type A card, so we look for type B
543 // power up the field
544 iso14443b_setup();
545 // select the card
546 return_code = iso14443b_select_card();
547 if (return_code == 1) {
548 Dbprintf("ISO 14443 Type B");
549 iso_type = 'b';
550 return 0;
5acd09bd 551 }
4be27083
FM
552 Dbprintf("No card found.");
553 return 1;
3bb07d96 554}
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