crypto/asn1/x_bignum.c

   1 /* x_bignum.c */
   2 /*
   3  * Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL project
   4  * 2000.
   5  */
   6 /* ====================================================================
   7  * Copyright (c) 2000 The OpenSSL Project.  All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  *
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  *
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in
  18  *    the documentation and/or other materials provided with the
  19  *    distribution.
  20  *
  21  * 3. All advertising materials mentioning features or use of this
  22  *    software must display the following acknowledgment:
  23  *    "This product includes software developed by the OpenSSL Project
  24  *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
  25  *
  26  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  27  *    endorse or promote products derived from this software without
  28  *    prior written permission. For written permission, please contact
  29  *    licensing@OpenSSL.org.
  30  *
  31  * 5. Products derived from this software may not be called "OpenSSL"
  32  *    nor may "OpenSSL" appear in their names without prior written
  33  *    permission of the OpenSSL Project.
  34  *
  35  * 6. Redistributions of any form whatsoever must retain the following
  36  *    acknowledgment:
  37  *    "This product includes software developed by the OpenSSL Project
  38  *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
  39  *
  40  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  41  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  42  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  43  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  44  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  45  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  46  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  47  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  49  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  50  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  51  * OF THE POSSIBILITY OF SUCH DAMAGE.
  52  * ====================================================================
  53  *
  54  * This product includes cryptographic software written by Eric Young
  55  * (eay@cryptsoft.com).  This product includes software written by Tim
  56  * Hudson (tjh@cryptsoft.com).
  57  *
  58  */
  59
  60 #include <stdio.h>
  61 #include "internal/cryptlib.h"
  62 #include <openssl/asn1t.h>
  63 #include <openssl/bn.h>
  64
  65 /*
  66  * Custom primitive type for BIGNUM handling. This reads in an ASN1_INTEGER
  67  * as a BIGNUM directly. Currently it ignores the sign which isn't a problem
  68  * since all BIGNUMs used are non negative and anything that looks negative
  69  * is normally due to an encoding error.
  70  */
  71
  72 #define BN_SENSITIVE    1
  73
  74 static int bn_new(ASN1_VALUE **pval, const ASN1_ITEM *it);
  75 static int bn_secure_new(ASN1_VALUE **pval, const ASN1_ITEM *it);
  76 static void bn_free(ASN1_VALUE **pval, const ASN1_ITEM *it);
  77
  78 static int bn_i2c(ASN1_VALUE **pval, unsigned char *cont, int *putype,
  79                   const ASN1_ITEM *it);
  80 static int bn_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len,
  81                   int utype, char *free_cont, const ASN1_ITEM *it);
  82 static int bn_secure_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len,
  83                          int utype, char *free_cont, const ASN1_ITEM *it);
  84
  85 static ASN1_PRIMITIVE_FUNCS bignum_pf = {
  86     NULL, 0,
  87     bn_new,
  88     bn_free,
  89     0,
  90     bn_c2i,
  91     bn_i2c
  92 };
  93
  94 static ASN1_PRIMITIVE_FUNCS cbignum_pf = {
  95     NULL, 0,
  96     bn_secure_new,
  97     bn_free,
  98     0,
  99     bn_secure_c2i,
 100     bn_i2c
 101 };
 102
 103 ASN1_ITEM_start(BIGNUM)
 104         ASN1_ITYPE_PRIMITIVE, V_ASN1_INTEGER, NULL, 0, &bignum_pf, 0, "BIGNUM"
 105 ASN1_ITEM_end(BIGNUM)
 106
 107 ASN1_ITEM_start(CBIGNUM)
 108         ASN1_ITYPE_PRIMITIVE, V_ASN1_INTEGER, NULL, 0, &cbignum_pf, BN_SENSITIVE, "CBIGNUM"
 109 ASN1_ITEM_end(CBIGNUM)
 110
 111 static int bn_new(ASN1_VALUE **pval, const ASN1_ITEM *it)
 112 {
 113     *pval = (ASN1_VALUE *)BN_new();
 114     if (*pval != NULL)
 115         return 1;
 116     else
 117         return 0;
 118 }
 119
 120 static int bn_secure_new(ASN1_VALUE **pval, const ASN1_ITEM *it)
 121 {
 122     *pval = (ASN1_VALUE *)BN_secure_new();
 123     if (*pval != NULL)
 124         return 1;
 125     else
 126         return 0;
 127 }
 128
 129 static void bn_free(ASN1_VALUE **pval, const ASN1_ITEM *it)
 130 {
 131     if (!*pval)
 132         return;
 133     if (it->size & BN_SENSITIVE)
 134         BN_clear_free((BIGNUM *)*pval);
 135     else
 136         BN_free((BIGNUM *)*pval);
 137     *pval = NULL;
 138 }
 139
 140 static int bn_i2c(ASN1_VALUE **pval, unsigned char *cont, int *putype,
 141                   const ASN1_ITEM *it)
 142 {
 143     BIGNUM *bn;
 144     int pad;
 145     if (!*pval)
 146         return -1;
 147     bn = (BIGNUM *)*pval;
 148     /* If MSB set in an octet we need a padding byte */
 149     if (BN_num_bits(bn) & 0x7)
 150         pad = 0;
 151     else
 152         pad = 1;
 153     if (cont) {
 154         if (pad)
 155             *cont++ = 0;
 156         BN_bn2bin(bn, cont);
 157     }
 158     return pad + BN_num_bytes(bn);
 159 }
 160
 161 static int bn_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len,
 162                   int utype, char *free_cont, const ASN1_ITEM *it)
 163 {
 164     BIGNUM *bn;
 165
 166     if (*pval == NULL && !bn_new(pval, it))
 167         return 0;
 168     bn = (BIGNUM *)*pval;
 169     if (!BN_bin2bn(cont, len, bn)) {
 170         bn_free(pval, it);
 171         return 0;
 172     }
 173     return 1;
 174 }
 175
 176 static int bn_secure_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len,
 177                          int utype, char *free_cont, const ASN1_ITEM *it)
 178 {
 179     if (!*pval)
 180         bn_secure_new(pval, it);
 181     return bn_c2i(pval, cont, len, utype, free_cont, it);
 182 }