crypto/asn1/x_bignum.c

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