| 1 | /* |
| 2 | * libopenemv - a library to work with EMV family of smart cards |
| 3 | * Copyright (C) 2012, 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 | /* For asprintf */ |
| 21 | #define _GNU_SOURCE |
| 22 | #include <stdio.h> |
| 23 | |
| 24 | #include "emv_pk.h" |
| 25 | #include "crypto.h" |
| 26 | #include "proxmark3.h" |
| 27 | |
| 28 | #include <stdbool.h> |
| 29 | #include <string.h> |
| 30 | #include <stdlib.h> |
| 31 | #include <sys/types.h> |
| 32 | |
| 33 | #define BCD(c) (((c) >= '0' && (c) <= '9') ? ((c) - '0') : \ |
| 34 | -1) |
| 35 | |
| 36 | #define HEX(c) (((c) >= '0' && (c) <= '9') ? ((c) - '0') : \ |
| 37 | ((c) >= 'A' && (c) <= 'F') ? ((c) - 'A' + 10) : \ |
| 38 | ((c) >= 'a' && (c) <= 'f') ? ((c) - 'a' + 10) : \ |
| 39 | -1) |
| 40 | |
| 41 | #define TOHEX(v) ((v) < 10 ? (v) + '0' : (v) - 10 + 'a') |
| 42 | |
| 43 | static ssize_t emv_pk_read_bin(char *buf, unsigned char *bin, size_t size, size_t *read) |
| 44 | { |
| 45 | size_t left = size; |
| 46 | char *p = buf; |
| 47 | while (*p && (*p == ' ' || *p == '\t')) |
| 48 | p++; |
| 49 | |
| 50 | while (left > 0) { |
| 51 | int c1, c2; |
| 52 | c1 = HEX(*p); |
| 53 | if (c1 == -1) |
| 54 | return -(p - buf); |
| 55 | p++; |
| 56 | c2 = HEX(*p); |
| 57 | if (c2 == -1) |
| 58 | return -(p - buf); |
| 59 | p++; |
| 60 | *bin = (c1 * 16 + c2); |
| 61 | bin ++; |
| 62 | left --; |
| 63 | if (*p == ':') |
| 64 | p++; |
| 65 | else if (read) { |
| 66 | *read = (size - left); |
| 67 | break; |
| 68 | } else if (left == 0) |
| 69 | break; |
| 70 | else |
| 71 | return -(p - buf); |
| 72 | } |
| 73 | |
| 74 | while (*p && (*p == ' ' || *p == '\t')) |
| 75 | p++; |
| 76 | |
| 77 | p--; |
| 78 | |
| 79 | return (p - buf); |
| 80 | } |
| 81 | |
| 82 | static ssize_t emv_pk_read_ymv(char *buf, unsigned *ymv) |
| 83 | { |
| 84 | int i; |
| 85 | unsigned char temp[3]; |
| 86 | char *p = buf; |
| 87 | |
| 88 | *ymv = 0; |
| 89 | |
| 90 | while (*p && (*p == ' ' || *p == '\t')) |
| 91 | p++; |
| 92 | |
| 93 | for (i = 0; i < 3; i++) { |
| 94 | int c1, c2; |
| 95 | c1 = BCD(*p); |
| 96 | if (c1 == -1) |
| 97 | return -(p - buf); |
| 98 | p++; |
| 99 | c2 = BCD(*p); |
| 100 | if (c2 == -1) |
| 101 | return -(p - buf); |
| 102 | p++; |
| 103 | temp[i] = (c1 * 16 + c2); |
| 104 | } |
| 105 | |
| 106 | while (*p && (*p == ' ' || *p == '\t')) |
| 107 | p++; |
| 108 | |
| 109 | p--; |
| 110 | |
| 111 | if (temp[1] > 0x12 || temp[2] > 0x31) |
| 112 | return -(p - buf); |
| 113 | |
| 114 | *ymv = (temp[0] * 0x10000 + temp[1] * 0x100 + temp[2]); |
| 115 | |
| 116 | return (p - buf); |
| 117 | } |
| 118 | |
| 119 | static ssize_t emv_pk_read_string(char *buf, char *str, size_t size) |
| 120 | { |
| 121 | char *p = buf; |
| 122 | while (*p && (*p == ' ' || *p == '\t')) |
| 123 | p++; |
| 124 | |
| 125 | while (size > 1) { |
| 126 | if (*p == ' ' || *p == '\t') |
| 127 | break; |
| 128 | else if (*p < 0x20 || *p >= 0x7f) |
| 129 | return -(p - buf); |
| 130 | *str = *p; |
| 131 | p++; |
| 132 | str ++; |
| 133 | size --; |
| 134 | } |
| 135 | |
| 136 | *str = 0; |
| 137 | |
| 138 | while (*p && (*p == ' ' || *p == '\t')) |
| 139 | p++; |
| 140 | |
| 141 | p--; |
| 142 | |
| 143 | return (p - buf); |
| 144 | } |
| 145 | |
| 146 | |
| 147 | struct emv_pk *emv_pk_parse_pk(char *buf) |
| 148 | { |
| 149 | struct emv_pk *r = calloc(1, sizeof(*r)); |
| 150 | ssize_t l; |
| 151 | char temp[10]; |
| 152 | |
| 153 | l = emv_pk_read_bin(buf, r->rid, 5, NULL); |
| 154 | if (l <= 0) |
| 155 | goto out; |
| 156 | buf += l; |
| 157 | |
| 158 | l = emv_pk_read_bin(buf, &r->index, 1, NULL); |
| 159 | if (l <= 0) |
| 160 | goto out; |
| 161 | buf += l; |
| 162 | |
| 163 | l = emv_pk_read_ymv(buf, &r->expire); |
| 164 | if (l <= 0) |
| 165 | goto out; |
| 166 | buf += l; |
| 167 | |
| 168 | l = emv_pk_read_string(buf, temp, sizeof(temp)); |
| 169 | if (l <= 0) |
| 170 | goto out; |
| 171 | buf += l; |
| 172 | |
| 173 | if (!strcmp(temp, "rsa")) |
| 174 | r->pk_algo = PK_RSA; |
| 175 | else |
| 176 | goto out; |
| 177 | |
| 178 | l = emv_pk_read_bin(buf, r->exp, sizeof(r->exp), &r->elen); |
| 179 | if (l <= 0) |
| 180 | goto out; |
| 181 | buf += l; |
| 182 | |
| 183 | r->modulus = malloc(2048/8); |
| 184 | l = emv_pk_read_bin(buf, r->modulus, 2048/8, &r->mlen); |
| 185 | if (l <= 0) |
| 186 | goto out2; |
| 187 | buf += l; |
| 188 | |
| 189 | l = emv_pk_read_string(buf, temp, sizeof(temp)); |
| 190 | if (l <= 0) |
| 191 | goto out2; |
| 192 | buf += l; |
| 193 | |
| 194 | if (!strcmp(temp, "sha1")) |
| 195 | r->hash_algo = HASH_SHA_1; |
| 196 | else |
| 197 | goto out2; |
| 198 | |
| 199 | l = emv_pk_read_bin(buf, r->hash, 20, NULL); |
| 200 | if (l <= 0) |
| 201 | goto out2; |
| 202 | |
| 203 | return r; |
| 204 | |
| 205 | out2: |
| 206 | free(r->modulus); |
| 207 | out: |
| 208 | free(r); |
| 209 | return NULL; |
| 210 | } |
| 211 | |
| 212 | static size_t emv_pk_write_bin(char *out, size_t outlen, const unsigned char *buf, size_t len) |
| 213 | { |
| 214 | int i; |
| 215 | size_t pos = 0; |
| 216 | |
| 217 | if (len == 0) |
| 218 | return 0; |
| 219 | if (outlen < len * 3) |
| 220 | return 0; |
| 221 | |
| 222 | out[pos++] = TOHEX(buf[0] >> 4); |
| 223 | out[pos++] = TOHEX(buf[0] & 0xf); |
| 224 | for (i = 1; i < len; i++) { |
| 225 | out[pos++] = ':'; |
| 226 | out[pos++] = TOHEX(buf[i] >> 4); |
| 227 | out[pos++] = TOHEX(buf[i] & 0xf); |
| 228 | } |
| 229 | out[pos++] = ' '; |
| 230 | |
| 231 | return pos; |
| 232 | } |
| 233 | |
| 234 | static size_t emv_pk_write_str(char *out, size_t outlen, const char *str) |
| 235 | { |
| 236 | size_t len = strlen(str); |
| 237 | |
| 238 | if (len == 0) |
| 239 | return 0; |
| 240 | if (outlen < len) |
| 241 | return 0; |
| 242 | |
| 243 | memcpy(out, str, len); |
| 244 | |
| 245 | return len; |
| 246 | } |
| 247 | |
| 248 | char *emv_pk_dump_pk(const struct emv_pk *pk) |
| 249 | { |
| 250 | size_t outsize = 1024; /* should be enough */ |
| 251 | char *out = malloc(outsize); /* should be enough */ |
| 252 | size_t outpos = 0; |
| 253 | size_t rc; |
| 254 | |
| 255 | if (!out) |
| 256 | return NULL; |
| 257 | |
| 258 | rc = emv_pk_write_bin(out + outpos, outsize - outpos, pk->rid, 5); |
| 259 | if (rc == 0) |
| 260 | goto err; |
| 261 | outpos += rc; |
| 262 | |
| 263 | rc = emv_pk_write_bin(out + outpos, outsize - outpos, &pk->index, 1); |
| 264 | if (rc == 0) |
| 265 | goto err; |
| 266 | outpos += rc; |
| 267 | |
| 268 | if (outpos + 7 > outsize) |
| 269 | goto err; |
| 270 | out[outpos++] = TOHEX((pk->expire >> 20) & 0xf); |
| 271 | out[outpos++] = TOHEX((pk->expire >> 16) & 0xf); |
| 272 | out[outpos++] = TOHEX((pk->expire >> 12) & 0xf); |
| 273 | out[outpos++] = TOHEX((pk->expire >> 8 ) & 0xf); |
| 274 | out[outpos++] = TOHEX((pk->expire >> 4 ) & 0xf); |
| 275 | out[outpos++] = TOHEX((pk->expire >> 0 ) & 0xf); |
| 276 | out[outpos++] = ' '; |
| 277 | |
| 278 | if (pk->pk_algo == PK_RSA) { |
| 279 | rc = emv_pk_write_str(out + outpos, outsize - outpos, "rsa"); |
| 280 | if (rc == 0) |
| 281 | goto err; |
| 282 | outpos += rc; |
| 283 | out[outpos++] = ' '; |
| 284 | } else { |
| 285 | if (outpos + 4 > outsize) |
| 286 | goto err; |
| 287 | out[outpos++] = '?'; |
| 288 | out[outpos++] = '?'; |
| 289 | out[outpos++] = TOHEX(pk->pk_algo >> 4); |
| 290 | out[outpos++] = TOHEX(pk->pk_algo & 0xf); |
| 291 | } |
| 292 | |
| 293 | rc = emv_pk_write_bin(out + outpos, outsize - outpos, pk->exp, pk->elen); |
| 294 | if (rc == 0) |
| 295 | goto err; |
| 296 | outpos += rc; |
| 297 | |
| 298 | rc = emv_pk_write_bin(out + outpos, outsize - outpos, pk->modulus, pk->mlen); |
| 299 | if (rc == 0) |
| 300 | goto err; |
| 301 | outpos += rc; |
| 302 | |
| 303 | if (pk->hash_algo == HASH_SHA_1) { |
| 304 | rc = emv_pk_write_str(out + outpos, outsize - outpos, "sha1"); |
| 305 | if (rc == 0) |
| 306 | goto err; |
| 307 | outpos += rc; |
| 308 | out[outpos++] = ' '; |
| 309 | } else { |
| 310 | if (outpos + 4 > outsize) |
| 311 | goto err; |
| 312 | out[outpos++] = '?'; |
| 313 | out[outpos++] = '?'; |
| 314 | out[outpos++] = TOHEX(pk->pk_algo >> 4); |
| 315 | out[outpos++] = TOHEX(pk->pk_algo & 0xf); |
| 316 | } |
| 317 | |
| 318 | |
| 319 | rc = emv_pk_write_bin(out + outpos, outsize - outpos, pk->hash, 20); |
| 320 | if (rc == 0) |
| 321 | goto err; |
| 322 | outpos += rc; |
| 323 | |
| 324 | out[outpos-1] = '\0'; |
| 325 | |
| 326 | return out; |
| 327 | |
| 328 | err: |
| 329 | free(out); |
| 330 | return NULL; |
| 331 | } |
| 332 | |
| 333 | bool emv_pk_verify(const struct emv_pk *pk) |
| 334 | { |
| 335 | struct crypto_hash *ch = crypto_hash_open(pk->hash_algo); |
| 336 | if (!ch) |
| 337 | return false; |
| 338 | |
| 339 | crypto_hash_write(ch, pk->rid, sizeof(pk->rid)); |
| 340 | crypto_hash_write(ch, &pk->index, 1); |
| 341 | crypto_hash_write(ch, pk->modulus, pk->mlen); |
| 342 | crypto_hash_write(ch, pk->exp, pk->elen); |
| 343 | |
| 344 | unsigned char *h = crypto_hash_read(ch); |
| 345 | if (!h) { |
| 346 | crypto_hash_close(ch); |
| 347 | return false; |
| 348 | } |
| 349 | |
| 350 | size_t hsize = crypto_hash_get_size(ch); |
| 351 | bool r = hsize && !memcmp(h, pk->hash, hsize) ? true : false; |
| 352 | |
| 353 | crypto_hash_close(ch); |
| 354 | |
| 355 | return r; |
| 356 | } |
| 357 | |
| 358 | struct emv_pk *emv_pk_new(size_t modlen, size_t explen) |
| 359 | { |
| 360 | struct emv_pk *pk; |
| 361 | |
| 362 | /* Not supported ATM */ |
| 363 | if (explen > 3) |
| 364 | return NULL; |
| 365 | |
| 366 | pk = calloc(1, sizeof(*pk)); |
| 367 | if (!pk) |
| 368 | return NULL; |
| 369 | |
| 370 | pk->mlen = modlen; |
| 371 | pk->elen = explen; |
| 372 | |
| 373 | pk->modulus = calloc(modlen, 1); |
| 374 | if (!pk->modulus) { |
| 375 | free(pk); |
| 376 | pk = NULL; |
| 377 | } |
| 378 | |
| 379 | return pk; |
| 380 | } |
| 381 | |
| 382 | void emv_pk_free(struct emv_pk *pk) |
| 383 | { |
| 384 | if (!pk) |
| 385 | return; |
| 386 | |
| 387 | free(pk->modulus); |
| 388 | free(pk); |
| 389 | } |
| 390 | |
| 391 | static struct emv_pk *emv_pk_get_ca_pk_from_file(const char *fname, |
| 392 | const unsigned char *rid, |
| 393 | unsigned char idx) |
| 394 | { |
| 395 | if (!fname) |
| 396 | return NULL; |
| 397 | |
| 398 | FILE *f = fopen(fname, "r"); |
| 399 | if (!f) { |
| 400 | perror("fopen"); |
| 401 | return NULL; |
| 402 | } |
| 403 | |
| 404 | while (!feof(f)) { |
| 405 | char buf[2048]; |
| 406 | if (fgets(buf, sizeof(buf), f) == NULL) |
| 407 | break; |
| 408 | |
| 409 | struct emv_pk *pk = emv_pk_parse_pk(buf); |
| 410 | if (!pk) |
| 411 | continue; |
| 412 | if (memcmp(pk->rid, rid, 5) || pk->index != idx) { |
| 413 | emv_pk_free(pk); |
| 414 | continue; |
| 415 | } |
| 416 | |
| 417 | fclose(f); |
| 418 | |
| 419 | return pk; |
| 420 | } |
| 421 | |
| 422 | fclose(f); |
| 423 | |
| 424 | return NULL; |
| 425 | } |
| 426 | |
| 427 | char *emv_pk_get_ca_pk_file(const char *dirname, const unsigned char *rid, unsigned char idx) |
| 428 | { |
| 429 | if (!dirname) |
| 430 | dirname = ".";//openemv_config_get_str("capk.dir", NULL); |
| 431 | |
| 432 | if (!dirname) |
| 433 | return NULL; |
| 434 | |
| 435 | char *filename; |
| 436 | int ret = asprintf(&filename, "%s/%02hhx%02hhx%02hhx%02hhx%02hhx_%02hhx.0", |
| 437 | dirname, |
| 438 | rid[0], |
| 439 | rid[1], |
| 440 | rid[2], |
| 441 | rid[3], |
| 442 | rid[4], |
| 443 | idx); |
| 444 | |
| 445 | if (ret <= 0) |
| 446 | return NULL; |
| 447 | |
| 448 | return filename; |
| 449 | } |
| 450 | |
| 451 | char *emv_pk_get_ca_pk_rid_file(const char *dirname, const unsigned char *rid) |
| 452 | { |
| 453 | if (!dirname) |
| 454 | dirname = "."; //openemv_config_get_str("capk.dir", NULL); |
| 455 | |
| 456 | if (!dirname) |
| 457 | return NULL; |
| 458 | |
| 459 | char *filename; |
| 460 | int ret = asprintf(&filename, "%s/%02hhx%02hhx%02hhx%02hhx%02hhx.pks", |
| 461 | dirname, |
| 462 | rid[0], |
| 463 | rid[1], |
| 464 | rid[2], |
| 465 | rid[3], |
| 466 | rid[4]); |
| 467 | |
| 468 | if (ret <= 0) |
| 469 | return NULL; |
| 470 | |
| 471 | return filename; |
| 472 | } |
| 473 | |
| 474 | struct emv_pk *emv_pk_get_ca_pk(const unsigned char *rid, unsigned char idx) |
| 475 | { |
| 476 | struct emv_pk *pk = NULL; |
| 477 | |
| 478 | /* if (!pk) { |
| 479 | char *fname = emv_pk_get_ca_pk_file(NULL, rid, idx); |
| 480 | if (fname) { |
| 481 | pk = emv_pk_get_ca_pk_from_file(fname, rid, idx); |
| 482 | free(fname); |
| 483 | } |
| 484 | } |
| 485 | |
| 486 | if (!pk) { |
| 487 | char *fname = emv_pk_get_ca_pk_rid_file(NULL, rid); |
| 488 | if (fname) { |
| 489 | pk = emv_pk_get_ca_pk_from_file(fname, rid, idx); |
| 490 | free(fname); |
| 491 | } |
| 492 | } |
| 493 | */ |
| 494 | if (!pk) { |
| 495 | const char *relfname = "emv/capk.txt"; |
| 496 | |
| 497 | char fname[strlen(get_my_executable_directory()) + strlen(relfname) + 1]; |
| 498 | strcpy(fname, get_my_executable_directory()); |
| 499 | strcat(fname, relfname); |
| 500 | |
| 501 | pk = emv_pk_get_ca_pk_from_file(fname, rid, idx); |
| 502 | } |
| 503 | if (!pk) |
| 504 | return NULL; |
| 505 | |
| 506 | printf("Verifying CA Public Key for %02hhx:%02hhx:%02hhx:%02hhx:%02hhx IDX %02hhx %zd bits...", |
| 507 | pk->rid[0], |
| 508 | pk->rid[1], |
| 509 | pk->rid[2], |
| 510 | pk->rid[3], |
| 511 | pk->rid[4], |
| 512 | pk->index, |
| 513 | pk->mlen * 8); |
| 514 | if (emv_pk_verify(pk)) { |
| 515 | printf("OK\n"); |
| 516 | |
| 517 | return pk; |
| 518 | } |
| 519 | |
| 520 | printf("Failed!\n"); |
| 521 | emv_pk_free(pk); |
| 522 | |
| 523 | return NULL; |
| 524 | } |