git.zerfleddert.de Git - proxmark3-svn/blob - armsrc/epa.c

   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 "../common/cmd.h"
  17
  18
  19 // Protocol and Parameter Selection Request
  20 // use regular (1x) speed in both directions
  21 // CRC is already included
  22 static 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
  27 static 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)
  38 static 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
  46 static 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
  57 static 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
  67 static 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
  78 //-----------------------------------------------------------------------------
  79 // Closes the communication channel and turns off the field
  80 //-----------------------------------------------------------------------------
  81 void EPA_Finish()
  82 {
  83         FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
  84         LEDsoff();
  85 }
  86
  87 //-----------------------------------------------------------------------------
  88 // Parses DER encoded data, e.g. from EF.CardAccess and fills out the given
  89 // structs. If a pointer is 0, it is ignored.
  90 // The function returns 0 on success and if an error occured, it returns the
  91 // offset where it occured.
  92 //
  93 // TODO: This function can access memory outside of the given data if the DER
  94 //       encoding is broken
  95 // TODO: Support skipping elements with a length > 0x7F
  96 // TODO: Support OIDs with a length > 7F
  97 // TODO: Support elements with long tags (tag is longer than 1 byte)
  98 // TODO: Support proprietary PACE domain parameters
  99 //-----------------------------------------------------------------------------
 100 size_t EPA_Parse_CardAccess(uint8_t *data,
 101                             size_t length,
 102                             pace_version_info_t *pace_info)
 103 {
 104         size_t index = 0;
 105
 106         while (index <= length - 2) {
 107                 // determine type of element
 108                 // SET or SEQUENCE
 109                 if (data[index] == 0x31 || data[index] == 0x30) {
 110                         // enter the set (skip tag + length)
 111                         index += 2;
 112                         // check for extended length
 113                         if ((data[index - 1] & 0x80) != 0) {
 114                                 index += (data[index-1] & 0x7F);
 115                         }
 116                 }
 117                 // OID
 118                 else if (data[index] == 0x06) {
 119                         // is this a PACE OID?
 120                         if (data[index + 1] == 0x0A // length matches
 121                             && memcmp(data + index + 2,
 122                                       oid_pace_start,
 123                                       sizeof(oid_pace_start)) == 0 // content matches
 124                             && pace_info != NULL)
 125                         {
 126                                 // first, clear the pace_info struct
 127                                 memset(pace_info, 0, sizeof(pace_version_info_t));
 128                                 memcpy(pace_info->oid, data + index + 2, sizeof(pace_info->oid));
 129                                 // a PACE OID is followed by the version
 130                                 index += data[index + 1] + 2;
 131                                 if (data[index] == 02 && data[index + 1] == 01) {
 132                                         pace_info->version = data[index + 2];
 133                                         index += 3;
 134                                 }
 135                                 else {
 136                                         return index;
 137                                 }
 138                                 // after that there might(!) be the parameter ID
 139                                 if (data[index] == 02 && data[index + 1] == 01) {
 140                                         pace_info->parameter_id = data[index + 2];
 141                                         index += 3;
 142                                 }
 143                         }
 144                         else {
 145                                 // skip this OID
 146                                 index += 2 + data[index + 1];
 147                         }
 148                 }
 149                 // if the length is 0, something is wrong
 150                 // TODO: This needs to be extended to support long tags
 151                 else if (data[index + 1] == 0) {
 152                         return index;
 153                 }
 154                 else {
 155                         // skip this part
 156                         // TODO: This needs to be extended to support long tags
 157                         // TODO: This needs to be extended to support unknown elements with
 158                         //       a size > 0x7F
 159                         index += 2 + data[index + 1];
 160                 }
 161         }
 162
 163         // TODO: We should check whether we reached the end in error, but for that
 164         //       we need a better parser (e.g. with states like IN_SET or IN_PACE_INFO)
 165         return 0;
 166 }
 167
 168 //-----------------------------------------------------------------------------
 169 // Read the file EF.CardAccess and save it into a buffer (at most max_length bytes)
 170 // Returns -1 on failure or the length of the data on success
 171 // TODO: for the moment this sends only 1 APDU regardless of the requested length
 172 //-----------------------------------------------------------------------------
 173 int EPA_Read_CardAccess(uint8_t *buffer, size_t max_length)
 174 {
 175         // the response APDU of the card
 176         // since the card doesn't always care for the expected length we send it,
 177         // we reserve 262 bytes here just to be safe (256-byte APDU + SW + ISO frame)
 178         uint8_t response_apdu[262];
 179         int rapdu_length = 0;
 180
 181         // select the file EF.CardAccess
 182         rapdu_length = iso14_apdu((uint8_t *)apdu_select_binary_cardaccess,
 183                                   sizeof(apdu_select_binary_cardaccess),
 184                                   response_apdu);
 185         if (rapdu_length != 6
 186             || response_apdu[rapdu_length - 4] != 0x90
 187             || response_apdu[rapdu_length - 3] != 0x00)
 188         {
 189                 Dbprintf("epa - no select cardaccess");
 190                 return -1;
 191         }
 192
 193         // read the file
 194         rapdu_length = iso14_apdu((uint8_t *)apdu_read_binary,
 195                                   sizeof(apdu_read_binary),
 196                                   response_apdu);
 197         if (rapdu_length <= 6
 198             || response_apdu[rapdu_length - 4] != 0x90
 199             || response_apdu[rapdu_length - 3] != 0x00)
 200         {
 201                 Dbprintf("epa - no read cardaccess");
 202                 return -1;
 203         }
 204
 205         // copy the content into the buffer
 206         // length of data available: apdu_length - 4 (ISO frame) - 2 (SW)
 207         size_t to_copy = rapdu_length - 6;
 208         to_copy = to_copy < max_length ? to_copy : max_length;
 209         memcpy(buffer, response_apdu+2, to_copy);
 210         return to_copy;
 211 }
 212
 213 //-----------------------------------------------------------------------------
 214 // Abort helper function for EPA_PACE_Collect_Nonce
 215 // sets relevant data in ack, sends the response
 216 //-----------------------------------------------------------------------------
 217 static void EPA_PACE_Collect_Nonce_Abort(uint8_t step, int func_return)
 218 {
 219 //      // step in which the failure occured
 220 //      ack->arg[0] = step;
 221 //      // last return code
 222 //      ack->arg[1] = func_return;
 223
 224         // power down the field
 225         EPA_Finish();
 226
 227         // send the USB packet
 228         cmd_send(CMD_ACK,step,func_return,0,0,0);
 229 }
 230
 231 //-----------------------------------------------------------------------------
 232 // Acquire one encrypted PACE nonce
 233 //-----------------------------------------------------------------------------
 234 void EPA_PACE_Collect_Nonce(UsbCommand *c)
 235 {
 236         /*
 237          * ack layout:
 238          *      arg:
 239          *              1. element
 240          *           step where the error occured or 0 if no error occured
 241      *       2. element
 242      *           return code of the last executed function
 243          *      d:
 244          *              Encrypted nonce
 245          */
 246
 247         // return value of a function
 248         int func_return = 0;
 249
 250 //      // initialize ack with 0s
 251 //      memset(ack->arg, 0, 12);
 252 //      memset(ack->d.asBytes, 0, 48);
 253
 254         // set up communication
 255         func_return = EPA_Setup();
 256         if (func_return != 0) {
 257                 EPA_PACE_Collect_Nonce_Abort(1, func_return);
 258                 Dbprintf("epa: setup fucked up! %d", func_return);
 259                 return;
 260         }
 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                 Dbprintf("epa: Too small!");
 269                 EPA_PACE_Collect_Nonce_Abort(2, card_access_length);
 270                 return;
 271         }
 272
 273         Dbprintf("epa: foo!");
 274
 275         // this will hold the PACE info of the card
 276         pace_version_info_t pace_version_info;
 277         // search for the PACE OID
 278         func_return = EPA_Parse_CardAccess(card_access,
 279                                            card_access_length,
 280                                            &pace_version_info);
 281         if (func_return != 0 || pace_version_info.version == 0) {
 282                 EPA_PACE_Collect_Nonce_Abort(3, func_return);
 283                 return;
 284         }
 285
 286         Dbprintf("epa: bar!");
 287
 288         // initiate the PACE protocol
 289         // use the CAN for the password since that doesn't change
 290         func_return = EPA_PACE_MSE_Set_AT(pace_version_info, 2);
 291
 292         // now get the nonce
 293         uint8_t nonce[256] = {0};
 294         uint8_t requested_size = (uint8_t)c->arg[0];
 295         func_return = EPA_PACE_Get_Nonce(requested_size, nonce);
 296         // check if the command succeeded
 297         if (func_return < 0)
 298         {
 299                 EPA_PACE_Collect_Nonce_Abort(4, func_return);
 300                 return;
 301         }
 302
 303   // all done, return
 304         EPA_Finish();
 305
 306         // save received information
 307 //      ack->arg[1] = func_return;
 308 //      memcpy(ack->d.asBytes, nonce, func_return);
 309         cmd_send(CMD_ACK,0,func_return,0,nonce,func_return);
 310 }
 311
 312 //-----------------------------------------------------------------------------
 313 // Performs the "Get Nonce" step of the PACE protocol and saves the returned
 314 // nonce. The caller is responsible for allocating enough memory to store the
 315 // nonce. Note that the returned size might be less or than or greater than the
 316 // requested size!
 317 // Returns the actual size of the nonce on success or a less-than-zero error
 318 // code on failure.
 319 //-----------------------------------------------------------------------------
 320 int EPA_PACE_Get_Nonce(uint8_t requested_length, uint8_t *nonce)
 321 {
 322         // build the APDU
 323         uint8_t apdu[sizeof(apdu_general_authenticate_pace_get_nonce) + 1];
 324         // copy the constant part
 325         memcpy(apdu,
 326                apdu_general_authenticate_pace_get_nonce,
 327                sizeof(apdu_general_authenticate_pace_get_nonce));
 328         // append Le (requested length + 2 due to tag/length taking 2 bytes) in RAPDU
 329         apdu[sizeof(apdu_general_authenticate_pace_get_nonce)] = requested_length + 4;
 330
 331         // send it
 332         uint8_t response_apdu[262];
 333         int send_return = iso14_apdu(apdu,
 334                                      sizeof(apdu),
 335                                      response_apdu);
 336         // check if the command succeeded
 337         if (send_return < 6
 338                 || response_apdu[send_return - 4] != 0x90
 339                 || response_apdu[send_return - 3] != 0x00)
 340         {
 341                 return -1;
 342         }
 343
 344         // if there is no nonce in the RAPDU, return here
 345         if (send_return < 10)
 346         {
 347                 // no error
 348                 return 0;
 349         }
 350         // get the actual length of the nonce
 351         uint8_t nonce_length = response_apdu[5];
 352         if (nonce_length > send_return - 10)
 353         {
 354                 nonce_length = send_return - 10;
 355         }
 356         // copy the nonce
 357         memcpy(nonce, response_apdu + 6, nonce_length);
 358
 359         return nonce_length;
 360 }
 361
 362 //-----------------------------------------------------------------------------
 363 // Initializes the PACE protocol by performing the "MSE: Set AT" step
 364 // Returns 0 on success or a non-zero error code on failure
 365 //-----------------------------------------------------------------------------
 366 int EPA_PACE_MSE_Set_AT(pace_version_info_t pace_version_info, uint8_t password)
 367 {
 368         // create the MSE: Set AT APDU
 369         uint8_t apdu[23];
 370         // the minimum length (will be increased as more data is added)
 371         size_t apdu_length = 20;
 372         // copy the constant part
 373         memcpy(apdu,
 374                apdu_mse_set_at_start,
 375                sizeof(apdu_mse_set_at_start));
 376         // type: OID
 377         apdu[5] = 0x80;
 378         // length of the OID
 379         apdu[6] = sizeof(pace_version_info.oid);
 380         // copy the OID
 381         memcpy(apdu + 7,
 382                pace_version_info.oid,
 383                sizeof(pace_version_info.oid));
 384         // type: password
 385         apdu[17] = 0x83;
 386         // length: 1
 387         apdu[18] = 1;
 388         // password
 389         apdu[19] = password;
 390         // if standardized domain parameters are used, copy the ID
 391         if (pace_version_info.parameter_id != 0) {
 392                 apdu_length += 3;
 393                 // type: domain parameter
 394                 apdu[20] = 0x84;
 395                 // length: 1
 396                 apdu[21] = 1;
 397                 // copy the parameter ID
 398                 apdu[22] = pace_version_info.parameter_id;
 399         }
 400         // now set Lc to the actual length
 401         apdu[4] = apdu_length - 5;
 402         // send it
 403         uint8_t response_apdu[6];
 404         int send_return = iso14_apdu(apdu,
 405                                      apdu_length,
 406                                      response_apdu);
 407         // check if the command succeeded
 408         if (send_return != 6
 409                 || response_apdu[send_return - 4] != 0x90
 410                 || response_apdu[send_return - 3] != 0x00)
 411         {
 412                 return 1;
 413         }
 414         return 0;
 415 }
 416
 417 //-----------------------------------------------------------------------------
 418 // Set up a communication channel (Card Select, PPS)
 419 // Returns 0 on success or a non-zero error code on failure
 420 //-----------------------------------------------------------------------------
 421 int EPA_Setup()
 422 {
 423
 424         int return_code = 0;
 425         uint8_t uid[10];
 426         uint8_t pps_response[3];
 427         uint8_t pps_response_par[1];
 428         iso14a_card_select_t card_select_info;
 429
 430         // power up the field
 431         iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD);
 432
 433         // select the card
 434         return_code = iso14443a_select_card(uid, &card_select_info, NULL);
 435         if (return_code != 1) {
 436                 Dbprintf("Epa: Can't select card");
 437                 return 1;
 438         }
 439
 440         // send the PPS request
 441         ReaderTransmit((uint8_t *)pps, sizeof(pps), NULL);
 442         return_code = ReaderReceive(pps_response, pps_response_par);
 443         if (return_code != 3 || pps_response[0] != 0xD0) {
 444                 return return_code == 0 ? 2 : return_code;
 445         }
 446
 447         return 0;
 448 }