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 <mbedtls/asn1.h>
  13
  14 int ecdsa_asn1_get_signature(uint8_t *signature, size_t signaturelen, uint8_t *rval, uint8_t *sval) {
  15         if (!signature || !signaturelen || !rval || !sval)
  16                 return 1;
  17
  18         int res = 0;
  19         unsigned char *p = signature;
  20         const unsigned char *end = p + signaturelen;
  21         size_t len;
  22         mbedtls_mpi xmpi;
  23
  24         if ((res = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE)) == 0) {
  25                 mbedtls_mpi_init(&xmpi);
  26                 res = mbedtls_asn1_get_mpi(&p, end, &xmpi);
  27                 if (res) {
  28                         mbedtls_mpi_free(&xmpi);
  29                         goto exit;
  30                 }
  31
  32                 res = mbedtls_mpi_write_binary(&xmpi, rval, 32);
  33                 mbedtls_mpi_free(&xmpi);
  34                 if (res)
  35                         goto exit;
  36
  37                 mbedtls_mpi_init(&xmpi);
  38                 res = mbedtls_asn1_get_mpi(&p, end, &xmpi);
  39                 if (res) {
  40                         mbedtls_mpi_free(&xmpi);
  41                         goto exit;
  42                 }
  43
  44                 res = mbedtls_mpi_write_binary(&xmpi, sval, 32);
  45                 mbedtls_mpi_free(&xmpi);
  46                 if (res)
  47                         goto exit;
  48
  49                 // check size
  50                 if (end != p)
  51                         return 2;
  52                 }
  53
  54 exit:
  55         return res;
  56 }
  57
  58 int asn1_print(uint8_t *asn1buf, int level) {
  59
  60         return 0;
  61 }
  62
  63