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 void bn_free(ASN1_VALUE **pval, const ASN1_ITEM *it);
  76
  77 static int bn_i2c(ASN1_VALUE **pval, unsigned char *cont, int *putype,
  78                   const ASN1_ITEM *it);
  79 static int bn_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len,
  80                   int utype, char *free_cont, const ASN1_ITEM *it);
  81
  82 static ASN1_PRIMITIVE_FUNCS bignum_pf = {
  83     NULL, 0,
  84     bn_new,
  85     bn_free,
  86     0,
  87     bn_c2i,
  88     bn_i2c
  89 };
  90
  91 ASN1_ITEM_start(BIGNUM)
  92         ASN1_ITYPE_PRIMITIVE, V_ASN1_INTEGER, NULL, 0, &bignum_pf, 0, "BIGNUM"
  93 ASN1_ITEM_end(BIGNUM)
  94
  95 ASN1_ITEM_start(CBIGNUM)
  96         ASN1_ITYPE_PRIMITIVE, V_ASN1_INTEGER, NULL, 0, &bignum_pf, BN_SENSITIVE, "BIGNUM"
  97 ASN1_ITEM_end(CBIGNUM)
  98
  99 static int bn_new(ASN1_VALUE **pval, const ASN1_ITEM *it)
 100 {
 101     *pval = (ASN1_VALUE *)BN_new();
 102     if (*pval)
 103         return 1;
 104     else
 105         return 0;
 106 }
 107
 108 static void bn_free(ASN1_VALUE **pval, const ASN1_ITEM *it)
 109 {
 110     if (!*pval)
 111         return;
 112     if (it->size & BN_SENSITIVE)
 113         BN_clear_free((BIGNUM *)*pval);
 114     else
 115         BN_free((BIGNUM *)*pval);
 116     *pval = NULL;
 117 }
 118
 119 static int bn_i2c(ASN1_VALUE **pval, unsigned char *cont, int *putype,
 120                   const ASN1_ITEM *it)
 121 {
 122     BIGNUM *bn;
 123     int pad;
 124     if (!*pval)
 125         return -1;
 126     bn = (BIGNUM *)*pval;
 127     /* If MSB set in an octet we need a padding byte */
 128     if (BN_num_bits(bn) & 0x7)
 129         pad = 0;
 130     else
 131         pad = 1;
 132     if (cont) {
 133         if (pad)
 134             *cont++ = 0;
 135         BN_bn2bin(bn, cont);
 136     }
 137     return pad + BN_num_bytes(bn);
 138 }
 139
 140 static int bn_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len,
 141                   int utype, char *free_cont, const ASN1_ITEM *it)
 142 {
 143     BIGNUM *bn;
 144     if (!*pval)
 145         bn_new(pval, it);
 146     bn = (BIGNUM *)*pval;
 147     if (!BN_bin2bn(cont, len, bn)) {
 148         bn_free(pval, it);
 149         return 0;
 150     }
 151     return 1;
 152 }