git.zerfleddert.de Git - proxmark3-svn/blob - client/crypto/asn1utils.c

   1 //-----------------------------------------------------------------------------
   2 // Copyright (C) 2018 Merlok
   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 // asn.1 utils
   9 //-----------------------------------------------------------------------------
  10
  11 #include "asn1utils.h"
  12 #include <ctype.h>
  13 #include <stdlib.h>
  14 #include <mbedtls/asn1.h>
  15 #include "emv/tlv.h"
  16 #include "emv/dump.h"
  17 #include "asn1dump.h"
  18 #include "util.h"
  19 #include "ui.h" // PrintAndLog
  20
  21 int ecdsa_asn1_get_signature(uint8_t *signature, size_t signaturelen, uint8_t *rval, uint8_t *sval) {
  22         if (!signature || !signaturelen || !rval || !sval)
  23                 return 1;
  24
  25         int res = 0;
  26         unsigned char *p = signature;
  27         const unsigned char *end = p + signaturelen;
  28         size_t len;
  29         mbedtls_mpi xmpi;
  30
  31         if ((res = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) == 0) {
  32                 mbedtls_mpi_init(&xmpi);
  33                 res = mbedtls_asn1_get_mpi(&p, end, &xmpi);
  34                 if (res) {
  35                         mbedtls_mpi_free(&xmpi);
  36                         goto exit;
  37                 }
  38
  39                 res = mbedtls_mpi_write_binary(&xmpi, rval, 32);
  40                 mbedtls_mpi_free(&xmpi);
  41                 if (res)
  42                         goto exit;
  43
  44                 mbedtls_mpi_init(&xmpi);
  45                 res = mbedtls_asn1_get_mpi(&p, end, &xmpi);
  46                 if (res) {
  47                         mbedtls_mpi_free(&xmpi);
  48                         goto exit;
  49                 }
  50
  51                 res = mbedtls_mpi_write_binary(&xmpi, sval, 32);
  52                 mbedtls_mpi_free(&xmpi);
  53                 if (res)
  54                         goto exit;
  55
  56                 // check size
  57                 if (end != p)
  58                         return 2;
  59                 }
  60
  61 exit:
  62         return res;
  63 }
  64
  65 static bool print_cb(void *data, const struct tlv *tlv, int level, bool is_leaf) {
  66         bool candump = true;
  67         asn1_tag_dump(tlv, stdout, level, &candump);
  68         if (is_leaf && candump) {
  69                 dump_buffer(tlv->value, tlv->len, stdout, level);
  70         }
  71
  72         return true;
  73 }
  74
  75 int asn1_print(uint8_t *asn1buf, size_t asn1buflen, char *indent) {
  76
  77         struct tlvdb *t = NULL;
  78         t = tlvdb_parse_multi(asn1buf, asn1buflen);
  79         if (t) {
  80                 tlvdb_visit(t, print_cb, NULL, 0);
  81                 tlvdb_free(t);
  82         } else {
  83                 PrintAndLogEx(ERR, "Can't parse data as TLV tree.");
  84                 return 1;
  85         }
  86
  87         return 0;
  88 }
  89
  90