git.zerfleddert.de Git - proxmark3-svn/blob - client/emv/emv_pki.c

   1 /*
   2  * libopenemv - a library to work with EMV family of smart cards
   3  * Copyright (C) 2015 Dmitry Eremin-Solenikov
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2.1 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  */
  15
  16 #ifdef HAVE_CONFIG_H
  17 #include <config.h>
  18 #endif
  19
  20 #include "emv_pki.h"
  21 #include "crypto.h"
  22 #include "dump.h"
  23 #include "util.h"
  24
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <stdarg.h>
  29
  30 static bool strictExecution = true;
  31 void PKISetStrictExecution(bool se) {
  32         strictExecution = se;
  33 }
  34
  35 static const unsigned char empty_tlv_value[] = {};
  36 static const struct tlv empty_tlv = {.tag = 0x0, .len = 0, .value = empty_tlv_value};
  37
  38 static size_t emv_pki_hash_psn[256] = { 0, 0, 11, 2, 17, 2, };
  39
  40 static unsigned char *emv_pki_decode_message(const struct emv_pk *enc_pk,
  41                 uint8_t msgtype,
  42                 size_t *len,
  43                 const struct tlv *cert_tlv,
  44                 ... /* A list of tlv pointers, end with NULL */
  45                 )
  46 {
  47         struct crypto_pk *kcp;
  48         unsigned char *data;
  49         size_t data_len;
  50         va_list vl;
  51
  52         if (!enc_pk)
  53                 return NULL;
  54
  55         if (!cert_tlv) {
  56                 printf("ERROR: Can't find certificate\n");
  57                 return NULL;
  58         }
  59
  60         if (cert_tlv->len != enc_pk->mlen) {
  61                 printf("ERROR: Certificate length (%zd) not equal key length (%zd)\n", cert_tlv->len, enc_pk->mlen);
  62                 return NULL;
  63         }
  64         kcp = crypto_pk_open(enc_pk->pk_algo,
  65                         enc_pk->modulus, enc_pk->mlen,
  66                         enc_pk->exp, enc_pk->elen);
  67         if (!kcp)
  68                 return NULL;
  69
  70         data = crypto_pk_encrypt(kcp, cert_tlv->value, cert_tlv->len, &data_len);
  71         crypto_pk_close(kcp);
  72
  73 /*      if (true){
  74                 printf("Recovered data:\n");
  75                 dump_buffer(data, data_len, stdout, 0);
  76         }*/
  77
  78         if (data[data_len-1] != 0xbc || data[0] != 0x6a || data[1] != msgtype) {
  79                 printf("ERROR: Certificate format\n");
  80                 free(data);
  81                 return NULL;
  82         }
  83
  84         size_t hash_pos = emv_pki_hash_psn[msgtype];
  85         if (hash_pos == 0 || hash_pos > data_len){
  86                 printf("ERROR: Cant get hash position in the certificate\n");
  87                 free(data);
  88                 return NULL;
  89         }
  90
  91         struct crypto_hash *ch;
  92         ch = crypto_hash_open(data[hash_pos]);
  93         if (!ch) {
  94                 printf("ERROR: Cant do hash\n");
  95                 free(data);
  96                 return NULL;
  97         }
  98
  99         size_t hash_len = crypto_hash_get_size(ch);
 100         crypto_hash_write(ch, data + 1, data_len - 2 - hash_len);
 101
 102         va_start(vl, cert_tlv);
 103         while (true) {
 104                 const struct tlv *add_tlv = va_arg(vl, const struct tlv *);
 105                 if (!add_tlv)
 106                         break;
 107
 108                 crypto_hash_write(ch, add_tlv->value, add_tlv->len);
 109         }
 110         va_end(vl);
 111
 112         if (memcmp(data + data_len - 1 - hash_len, crypto_hash_read(ch), hash_len)) {
 113                 printf("ERROR: Calculated wrong hash\n");
 114                 printf("decoded:    %s\n",sprint_hex(data + data_len - 1 - hash_len, hash_len));
 115                 printf("calculated: %s\n",sprint_hex(crypto_hash_read(ch), hash_len));
 116
 117                 if (strictExecution) {
 118                         crypto_hash_close(ch);
 119                         free(data);
 120                         return NULL;
 121                 }
 122         }
 123
 124         crypto_hash_close(ch);
 125
 126         *len = data_len - hash_len - 1;
 127
 128         return data;
 129 }
 130
 131 static unsigned emv_cn_length(const struct tlv *tlv)
 132 {
 133         int i;
 134
 135         for (i = 0; i < tlv->len; i++) {
 136                 unsigned char c = tlv->value[i];
 137
 138                 if (c >> 4 == 0xf)
 139                         return 2 * i;
 140
 141                 if ((c & 0xf) == 0xf)
 142                         return 2 * i + 1;
 143         }
 144
 145         return 2 * tlv->len;
 146 }
 147
 148 static unsigned char emv_cn_get(const struct tlv *tlv, unsigned pos)
 149 {
 150         if (pos > tlv->len * 2)
 151                 return 0xf;
 152
 153         unsigned char c = tlv->value[pos / 2];
 154
 155         if (pos % 2)
 156                 return c & 0xf;
 157         else
 158                 return c >> 4;
 159 }
 160
 161 static struct emv_pk *emv_pki_decode_key_ex(const struct emv_pk *enc_pk,
 162                 unsigned char msgtype,
 163                 const struct tlv *pan_tlv,
 164                 const struct tlv *cert_tlv,
 165                 const struct tlv *exp_tlv,
 166                 const struct tlv *rem_tlv,
 167                 const struct tlv *add_tlv,
 168                 bool showData
 169                 )
 170 {
 171         size_t pan_length;
 172         unsigned char *data;
 173         size_t data_len;
 174         size_t pk_len;
 175
 176         if (!cert_tlv || !exp_tlv || !pan_tlv)
 177                 return NULL;
 178
 179         if (!rem_tlv)
 180                 rem_tlv = &empty_tlv;
 181
 182         if (msgtype == 2)
 183                 pan_length = 4;
 184         else if (msgtype == 4)
 185                 pan_length = 10;
 186         else {
 187                 printf("ERROR: Message type must be 2 or 4\n");
 188                 return NULL;
 189         }
 190
 191         data = emv_pki_decode_message(enc_pk, msgtype, &data_len,
 192                         cert_tlv,
 193                         rem_tlv,
 194                         exp_tlv,
 195                         add_tlv,
 196                         NULL);
 197         if (!data || data_len < 11 + pan_length) {
 198                 printf("ERROR: Can't decode message\n");
 199                 return NULL;
 200         }
 201
 202         if (showData){
 203                 printf("Recovered data:\n");
 204                 dump_buffer(data, data_len, stdout, 0);
 205         }
 206
 207         /* Perform the rest of checks here */
 208
 209         struct tlv pan2_tlv = {
 210                 .tag = 0x5a,
 211                 .len = pan_length,
 212                 .value = &data[2],
 213         };
 214         unsigned pan_len = emv_cn_length(pan_tlv);
 215         unsigned pan2_len = emv_cn_length(&pan2_tlv);
 216
 217         if (((msgtype == 2) && (pan2_len < 4 || pan2_len > pan_len)) ||
 218             ((msgtype == 4) && (pan2_len != pan_len))) {
 219                 printf("ERROR: Invalid PAN lengths\n");
 220                 free(data);
 221
 222                 return NULL;
 223         }
 224
 225         unsigned i;
 226         for (i = 0; i < pan2_len; i++)
 227                 if (emv_cn_get(pan_tlv, i) != emv_cn_get(&pan2_tlv, i)) {
 228                         printf("ERROR: PAN data mismatch\n");
 229                         printf("tlv  pan=%s\n", sprint_hex(pan_tlv->value, pan_tlv->len));
 230                         printf("cert pan=%s\n", sprint_hex(pan2_tlv.value, pan2_tlv.len));
 231                         free(data);
 232
 233                         return NULL;
 234                 }
 235
 236         pk_len = data[9 + pan_length];
 237         if (pk_len > data_len - 11 - pan_length + rem_tlv->len) {
 238                 printf("ERROR: Invalid pk length\n");
 239                 free(data);
 240                 return NULL;
 241         }
 242
 243         if (exp_tlv->len != data[10 + pan_length]) {
 244                 free(data);
 245                 return NULL;
 246         }
 247
 248         struct emv_pk *pk = emv_pk_new(pk_len, exp_tlv->len);
 249
 250         memcpy(pk->rid, enc_pk->rid, 5);
 251         pk->index = enc_pk->index;
 252
 253         pk->hash_algo = data[7 + pan_length];
 254         pk->pk_algo = data[8 + pan_length];
 255         pk->expire = (data[3 + pan_length] << 16) | (data[2 + pan_length] << 8) | 0x31;
 256         memcpy(pk->serial, data + 4 + pan_length, 3);
 257         memcpy(pk->pan, data + 2, pan_length);
 258         memset(pk->pan + pan_length, 0xff, 10 - pan_length);
 259
 260         memcpy(pk->modulus, data + 11 + pan_length,
 261                         pk_len < data_len - (11 + pan_length) ?
 262                         pk_len :
 263                         data_len - (11 + pan_length));
 264         memcpy(pk->modulus + data_len - (11 + pan_length), rem_tlv->value, rem_tlv->len);
 265         memcpy(pk->exp, exp_tlv->value, exp_tlv->len);
 266
 267         free(data);
 268
 269         return pk;
 270 }
 271
 272 static struct emv_pk *emv_pki_decode_key(const struct emv_pk *enc_pk,
 273                 unsigned char msgtype,
 274                 const struct tlv *pan_tlv,
 275                 const struct tlv *cert_tlv,
 276                 const struct tlv *exp_tlv,
 277                 const struct tlv *rem_tlv,
 278                 const struct tlv *add_tlv
 279                 ) {
 280         return emv_pki_decode_key_ex(enc_pk, msgtype, pan_tlv, cert_tlv, exp_tlv, rem_tlv, add_tlv, false);
 281 }
 282
 283 struct emv_pk *emv_pki_recover_issuer_cert(const struct emv_pk *pk, struct tlvdb *db)
 284 {
 285         return emv_pki_decode_key(pk, 2,
 286                         tlvdb_get(db, 0x5a, NULL),
 287                         tlvdb_get(db, 0x90, NULL),
 288                         tlvdb_get(db, 0x9f32, NULL),
 289                         tlvdb_get(db, 0x92, NULL),
 290                         NULL);
 291 }
 292
 293 struct emv_pk *emv_pki_recover_icc_cert(const struct emv_pk *pk, struct tlvdb *db, const struct tlv *sda_tlv)
 294 {
 295         return emv_pki_decode_key(pk, 4,
 296                         tlvdb_get(db, 0x5a, NULL),
 297                         tlvdb_get(db, 0x9f46, NULL),
 298                         tlvdb_get(db, 0x9f47, NULL),
 299                         tlvdb_get(db, 0x9f48, NULL),
 300                         sda_tlv);
 301 }
 302
 303 struct emv_pk *emv_pki_recover_icc_pe_cert(const struct emv_pk *pk, struct tlvdb *db)
 304 {
 305         return emv_pki_decode_key(pk, 4,
 306                         tlvdb_get(db, 0x5a, NULL),
 307                         tlvdb_get(db, 0x9f2d, NULL),
 308                         tlvdb_get(db, 0x9f2e, NULL),
 309                         tlvdb_get(db, 0x9f2f, NULL),
 310                         NULL);
 311 }
 312
 313 struct tlvdb *emv_pki_recover_dac_ex(const struct emv_pk *enc_pk, const struct tlvdb *db, const struct tlv *sda_tlv, bool showData)
 314 {
 315         size_t data_len;
 316         unsigned char *data = emv_pki_decode_message(enc_pk, 3, &data_len,
 317                         tlvdb_get(db, 0x93, NULL),
 318                         sda_tlv,
 319                         NULL);
 320
 321         if (!data || data_len < 5)
 322                 return NULL;
 323
 324         if (showData){
 325                 printf("Recovered data:\n");
 326                 dump_buffer(data, data_len, stdout, 0);
 327         }
 328
 329         struct tlvdb *dac_db = tlvdb_fixed(0x9f45, 2, data+3);
 330
 331         free(data);
 332
 333         return dac_db;
 334 }
 335 struct tlvdb *emv_pki_recover_dac(const struct emv_pk *enc_pk, const struct tlvdb *db, const struct tlv *sda_tlv) {
 336         return emv_pki_recover_dac_ex(enc_pk, db, sda_tlv, false);
 337 }
 338
 339 struct tlvdb *emv_pki_recover_idn(const struct emv_pk *enc_pk, const struct tlvdb *db, const struct tlv *dyn_tlv) {
 340         return emv_pki_recover_idn_ex(enc_pk, db, dyn_tlv, false);
 341 }
 342
 343 struct tlvdb *emv_pki_recover_idn_ex(const struct emv_pk *enc_pk, const struct tlvdb *db, const struct tlv *dyn_tlv, bool showData)
 344 {
 345         size_t data_len;
 346         unsigned char *data = emv_pki_decode_message(enc_pk, 5, &data_len,
 347                         tlvdb_get(db, 0x9f4b, NULL),
 348                         dyn_tlv,
 349                         NULL);
 350
 351         if (!data || data_len < 3)
 352                 return NULL;
 353
 354         if (data[3] < 2 || data[3] > data_len - 3) {
 355                 free(data);
 356                 return NULL;
 357         }
 358
 359         if (showData){
 360                 printf("Recovered data:\n");
 361                 dump_buffer(data, data_len, stdout, 0);
 362         }
 363
 364         size_t idn_len = data[4];
 365         if (idn_len > data[3] - 1) {
 366                 free(data);
 367                 return NULL;
 368         }
 369
 370         // 9f4c ICC Dynamic Number
 371         struct tlvdb *idn_db = tlvdb_fixed(0x9f4c, idn_len, data + 5);
 372
 373         free(data);
 374
 375         return idn_db;
 376 }
 377
 378 struct tlvdb *emv_pki_recover_atc_ex(const struct emv_pk *enc_pk, const struct tlvdb *db, bool showData)
 379 {
 380         size_t data_len;
 381         unsigned char *data = emv_pki_decode_message(enc_pk, 5, &data_len,
 382                         tlvdb_get(db, 0x9f4b, NULL),
 383                         tlvdb_get(db, 0x9f37, NULL),
 384                         tlvdb_get(db, 0x9f02, NULL),
 385                         tlvdb_get(db, 0x5f2a, NULL),
 386                         tlvdb_get(db, 0x9f69, NULL),
 387                         NULL);
 388
 389         if (!data || data_len < 3)
 390                 return NULL;
 391
 392         if (data[3] < 2 || data[3] > data_len - 3) {
 393                 free(data);
 394                 return NULL;
 395         }
 396
 397         if (showData){
 398                 printf("Recovered data:\n");
 399                 dump_buffer(data, data_len, stdout, 0);
 400         }
 401
 402         size_t idn_len = data[4];
 403         if (idn_len > data[3] - 1) {
 404                 free(data);
 405                 return NULL;
 406         }
 407
 408         // 9f36 Application Transaction Counter (ATC)
 409         struct tlvdb *atc_db = tlvdb_fixed(0x9f36, idn_len, data + 5);
 410
 411         free(data);
 412
 413         return atc_db;
 414 }
 415
 416 static bool tlv_hash(void *data, const struct tlv *tlv, int level, bool is_leaf)
 417 {
 418         struct crypto_hash *ch = data;
 419         size_t tag_len;
 420         unsigned char *tag;
 421
 422         if (tlv_is_constructed(tlv))
 423                 return true;
 424
 425         if (tlv->tag == 0x9f4b)
 426                 return true;
 427
 428         tag = tlv_encode(tlv, &tag_len);
 429         crypto_hash_write(ch, tag, tag_len);
 430         free(tag);
 431
 432         return true;
 433 }
 434
 435 struct tlvdb *emv_pki_perform_cda(const struct emv_pk *enc_pk, const struct tlvdb *db,
 436                 const struct tlvdb *this_db,
 437                 const struct tlv *pdol_data_tlv,
 438                 const struct tlv *crm1_tlv,
 439                 const struct tlv *crm2_tlv)
 440 {
 441         return emv_pki_perform_cda_ex(enc_pk, db, this_db, pdol_data_tlv, crm1_tlv, crm2_tlv, false);
 442 }
 443 struct tlvdb *emv_pki_perform_cda_ex(const struct emv_pk *enc_pk, const struct tlvdb *db,
 444                 const struct tlvdb *this_db,     // AC TLV result
 445                 const struct tlv *pdol_data_tlv, // PDOL
 446                 const struct tlv *crm1_tlv,      // CDOL1
 447                 const struct tlv *crm2_tlv,      // CDOL2
 448                 bool showData)
 449 {
 450         const struct tlv *un_tlv = tlvdb_get(db, 0x9f37, NULL);
 451         const struct tlv *cid_tlv = tlvdb_get(this_db, 0x9f27, NULL);
 452
 453         if (!un_tlv || !cid_tlv)
 454                 return NULL;
 455
 456         size_t data_len = 0;
 457         unsigned char *data = emv_pki_decode_message(enc_pk, 5, &data_len,
 458                         tlvdb_get(this_db, 0x9f4b, NULL),
 459                         un_tlv,
 460                         NULL);
 461         if (!data || data_len < 3) {
 462                 printf("ERROR: can't decode message. len %zd\n", data_len);
 463                 return NULL;
 464         }
 465
 466         if (showData){
 467                 printf("Recovered data:\n");
 468                 dump_buffer(data, data_len, stdout, 0);
 469         }
 470
 471         if (data[3] < 30 || data[3] > data_len - 4) {
 472                 printf("ERROR: Invalid data length\n");
 473                 free(data);
 474                 return NULL;
 475         }
 476
 477         if (!cid_tlv || cid_tlv->len != 1 || cid_tlv->value[0] != data[5 + data[4]]) {
 478                 printf("ERROR: CID mismatch\n");
 479                 free(data);
 480                 return NULL;
 481         }
 482
 483         struct crypto_hash *ch;
 484         ch = crypto_hash_open(enc_pk->hash_algo);
 485         if (!ch) {
 486                 printf("ERROR: can't create hash\n");
 487                 free(data);
 488                 return NULL;
 489         }
 490
 491         if (pdol_data_tlv)
 492                 crypto_hash_write(ch, pdol_data_tlv->value, pdol_data_tlv->len);
 493         if (crm1_tlv)
 494                 crypto_hash_write(ch, crm1_tlv->value, crm1_tlv->len);
 495         if (crm2_tlv)
 496                 crypto_hash_write(ch, crm2_tlv->value, crm2_tlv->len);
 497
 498         tlvdb_visit(this_db, tlv_hash, ch, 0);
 499
 500         if (memcmp(data + 5 + data[4] + 1 + 8, crypto_hash_read(ch), 20)) {
 501                 printf("ERROR: calculated hash error\n");
 502                 crypto_hash_close(ch);
 503                 free(data);
 504                 return NULL;
 505         }
 506         crypto_hash_close(ch);
 507
 508         size_t idn_len = data[4];
 509         if (idn_len > data[3] - 1) {
 510                 printf("ERROR: Invalid IDN length\n");
 511                 free(data);
 512                 return NULL;
 513         }
 514
 515         struct tlvdb *idn_db = tlvdb_fixed(0x9f4c, idn_len, data + 5);
 516         free(data);
 517
 518         return idn_db;
 519 }