client/src/emv/emv_roca.c

   1 //-----------------------------------------------------------------------------
   2 // Borrowed initially from https://gist.github.com/robstradling/f525d423c79690b72e650e2ad38a161d
   3 // Copyright (C) 2017-2018 Rob Stradling
   4 // Copyright (C) 2017-2018 Sectigo Limited
   5 // Copyright (C) Proxmark3 contributors. See AUTHORS.md for details.
   6 //
   7 // This program is free software: you can redistribute it and/or modify
   8 // it under the terms of the GNU General Public License as published by
   9 // the Free Software Foundation, either version 3 of the License, or
  10 // (at your option) any later version.
  11 //
  12 // This program is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16 //
  17 // See LICENSE.txt for the text of the license.
  18 //-----------------------------------------------------------------------------
  19 // roca.c - ROCA (CVE-2017-15361) fingerprint checker.
  20 //-----------------------------------------------------------------------------
  21
  22 #include "emv_roca.h"
  23
  24 #include "ui.h"  // Print...
  25 #include "bignum.h"
  26
  27 static void rocacheck_init(mbedtls_mpi *prints) {
  28
  29     for (int i = 0; i < ROCA_PRINTS_LENGTH; i++)
  30         mbedtls_mpi_init(&prints[i]);
  31
  32     mbedtls_mpi_read_string(&prints[0], 10, "1026");
  33     mbedtls_mpi_read_string(&prints[1], 10, "5658");
  34     mbedtls_mpi_read_string(&prints[2], 10, "107286");
  35     mbedtls_mpi_read_string(&prints[3], 10, "199410");
  36     mbedtls_mpi_read_string(&prints[4], 10, "67109890");
  37     mbedtls_mpi_read_string(&prints[5], 10, "5310023542746834");
  38     mbedtls_mpi_read_string(&prints[6], 10, "1455791217086302986");
  39     mbedtls_mpi_read_string(&prints[7], 10, "20052041432995567486");
  40     mbedtls_mpi_read_string(&prints[8], 10, "6041388139249378920330");
  41     mbedtls_mpi_read_string(&prints[9], 10, "207530445072488465666");
  42     mbedtls_mpi_read_string(&prints[10], 10, "79228162521181866724264247298");
  43     mbedtls_mpi_read_string(&prints[11], 10, "1760368345969468176824550810518");
  44     mbedtls_mpi_read_string(&prints[12], 10, "50079290986288516948354744811034");
  45     mbedtls_mpi_read_string(&prints[13], 10, "473022961816146413042658758988474");
  46     mbedtls_mpi_read_string(&prints[14], 10, "144390480366845522447407333004847678774");
  47     mbedtls_mpi_read_string(&prints[15], 10, "1800793591454480341970779146165214289059119882");
  48     mbedtls_mpi_read_string(&prints[16], 10, "126304807362733370595828809000324029340048915994");
  49 }
  50
  51 static void rocacheck_cleanup(mbedtls_mpi *prints) {
  52     for (int i = 0; i < ROCA_PRINTS_LENGTH; i++)
  53         mbedtls_mpi_free(&prints[i]);
  54 }
  55
  56 static int bitand_is_zero(mbedtls_mpi *a, mbedtls_mpi *b) {
  57
  58     for (int i = 0; i < mbedtls_mpi_bitlen(a); i++) {
  59
  60         if (mbedtls_mpi_get_bit(a, i) && mbedtls_mpi_get_bit(b, i))
  61             return 0;
  62     }
  63     return 1;
  64 }
  65
  66
  67 static mbedtls_mpi_uint mpi_get_uint(const mbedtls_mpi *X) {
  68
  69     if (X->n == 1 && X->s > 0) {
  70         return X->p[0];
  71     }
  72
  73     PrintAndLogEx(WARNING, "ZERRRRO!!!\n");
  74     return 0;
  75 }
  76
  77 /*
  78 static void print_mpi(const char *msg, int radix, const mbedtls_mpi *X) {
  79
  80     char Xchar[400] = {0};
  81     size_t len = 0;
  82
  83     mbedtls_mpi_write_string(X, radix, Xchar, sizeof(Xchar), &len);
  84     PrintAndLogEx(INFO, "%s[%zu] %s\n", msg, len, Xchar);
  85 }
  86 */
  87 bool emv_rocacheck(const unsigned char *buf, size_t buflen, bool verbose) {
  88
  89     mbedtls_mpi t_modulus;
  90     mbedtls_mpi_init(&t_modulus);
  91
  92     bool ret = false;
  93     mbedtls_mpi prints[ROCA_PRINTS_LENGTH];
  94     uint8_t primes[ROCA_PRINTS_LENGTH] = {
  95         11, 13, 17, 19, 37, 53, 61, 71, 73, 79, 97, 103, 107, 109, 127, 151, 157
  96     };
  97
  98     rocacheck_init(prints);
  99
 100     MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&t_modulus, buf, buflen));
 101
 102     for (int i = 0; i < ROCA_PRINTS_LENGTH; i++) {
 103
 104         mbedtls_mpi t_temp;
 105         mbedtls_mpi t_prime;
 106         mbedtls_mpi g_one;
 107
 108         mbedtls_mpi_init(&t_temp);
 109         mbedtls_mpi_init(&t_prime);
 110         mbedtls_mpi_init(&g_one);
 111
 112         MBEDTLS_MPI_CHK(mbedtls_mpi_read_string(&g_one, 10, "1"));
 113
 114         MBEDTLS_MPI_CHK(mbedtls_mpi_add_int(&t_prime, &t_prime, primes[i]));
 115
 116         MBEDTLS_MPI_CHK(mbedtls_mpi_mod_mpi(&t_temp, &t_modulus, &t_prime));
 117
 118         MBEDTLS_MPI_CHK(mbedtls_mpi_shift_l(&g_one, mpi_get_uint(&t_temp)));
 119
 120         mbedtls_mpi_free(&t_temp);
 121         mbedtls_mpi_free(&t_prime);
 122
 123         if (bitand_is_zero(&g_one, &prints[i])) {
 124             if (verbose) {
 125                 PrintAndLogEx(FAILED, "No fingerprint found.\n");
 126             }
 127             mbedtls_mpi_free(&g_one);
 128             goto cleanup;
 129         }
 130         mbedtls_mpi_free(&g_one);
 131     }
 132
 133     ret = true;
 134     if (verbose)
 135         PrintAndLogEx(SUCCESS, "Fingerprint found!\n");
 136
 137 cleanup:
 138     mbedtls_mpi_free(&t_modulus);
 139
 140     rocacheck_cleanup(prints);
 141     return ret;
 142 }
 143
 144 int roca_self_test(void) {
 145     PrintAndLogEx(NORMAL, "");
 146     PrintAndLogEx(INFO, "ROCA check vulnerability tests");
 147
 148     // positive
 149     uint8_t keyp[] = "\x94\x4e\x13\x20\x8a\x28\x0c\x37\xef\xc3\x1c\x31\x14\x48\x5e\x59"\
 150                      "\x01\x92\xad\xbb\x8e\x11\xc8\x7c\xad\x60\xcd\xef\x00\x37\xce\x99"\
 151                      "\x27\x83\x30\xd3\xf4\x71\xa2\x53\x8f\xa6\x67\x80\x2e\xd2\xa3\xc4"\
 152                      "\x4a\x8b\x7d\xea\x82\x6e\x88\x8d\x0a\xa3\x41\xfd\x66\x4f\x7f\xa7";
 153
 154     int ret = 0;
 155     if (emv_rocacheck(keyp, 64, false)) {
 156         PrintAndLogEx(SUCCESS, "Weak modulus   ( %s )", _GREEN_("ok"));
 157     } else {
 158         ret++;
 159         PrintAndLogEx(FAILED, "Weak modulus   ( %s )", _RED_("fail"));
 160     }
 161
 162     // negative
 163     uint8_t keyn[] = "\x84\x4e\x13\x20\x8a\x28\x0c\x37\xef\xc3\x1c\x31\x14\x48\x5e\x59"\
 164                      "\x01\x92\xad\xbb\x8e\x11\xc8\x7c\xad\x60\xcd\xef\x00\x37\xce\x99"\
 165                      "\x27\x83\x30\xd3\xf4\x71\xa2\x53\x8f\xa6\x67\x80\x2e\xd2\xa3\xc4"\
 166                      "\x4a\x8b\x7d\xea\x82\x6e\x88\x8d\x0a\xa3\x41\xfd\x66\x4f\x7f\xa7";
 167
 168     if (emv_rocacheck(keyn, 64, false)) {
 169         ret++;
 170         PrintAndLogEx(FAILED, "Strong modulus ( %s )", _RED_("fail"));
 171     } else {
 172         PrintAndLogEx(SUCCESS, "Strong modulus ( %s )", _GREEN_("ok"));
 173     }
 174     return ret;
 175 }