crypto/libressl/crypto/asn1/x_bignum.c

   1 /* $OpenBSD: x_bignum.c,v 1.7 2014/07/12 16:42:47 miod Exp $ */
   2 /* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
   3  * project 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
  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 as a
  66  * BIGNUM directly. Currently it ignores the sign which isn't a problem since
  67  * all BIGNUMs used are non negative and anything that looks negative is
  68  * normally due to an encoding error.
  69  */
  70
  71 static int bn_new(ASN1_VALUE **pval, const ASN1_ITEM *it);
  72 static void bn_free(ASN1_VALUE **pval, const ASN1_ITEM *it);
  73
  74 static int bn_i2c(ASN1_VALUE **pval, unsigned char *cont, int *putype,
  75     const ASN1_ITEM *it);
  76 static int bn_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len,
  77     int utype, char *free_cont, const ASN1_ITEM *it);
  78
  79 static ASN1_PRIMITIVE_FUNCS bignum_pf = {
  80         NULL,
  81         0,
  82         bn_new,
  83         bn_free,
  84         0,
  85         bn_c2i,
  86         bn_i2c
  87 };
  88
  89 const ASN1_ITEM BIGNUM_it = {
  90         .itype = ASN1_ITYPE_PRIMITIVE,
  91         .utype = V_ASN1_INTEGER,
  92         .templates = NULL,
  93         .tcount = 0,
  94         .funcs = &bignum_pf,
  95         .size = 0,
  96         .sname = "BIGNUM",
  97 };
  98
  99 const ASN1_ITEM CBIGNUM_it = {
 100         .itype = ASN1_ITYPE_PRIMITIVE,
 101         .utype = V_ASN1_INTEGER,
 102         .templates = NULL,
 103         .tcount = 0,
 104         .funcs = &bignum_pf,
 105         .size = 0,
 106         .sname = "BIGNUM",
 107 };
 108
 109 static int
 110 bn_new(ASN1_VALUE **pval, const ASN1_ITEM *it)
 111 {
 112         *pval = (ASN1_VALUE *)BN_new();
 113         if (*pval)
 114                 return 1;
 115         else
 116                 return 0;
 117 }
 118
 119 static void
 120 bn_free(ASN1_VALUE **pval, const ASN1_ITEM *it)
 121 {
 122         if (*pval == NULL)
 123                 return;
 124         BN_clear_free((BIGNUM *)*pval);
 125         *pval = NULL;
 126 }
 127
 128 static int
 129 bn_i2c(ASN1_VALUE **pval, unsigned char *cont, int *putype, const ASN1_ITEM *it)
 130 {
 131         BIGNUM *bn;
 132         int pad, len;
 133
 134         if (*pval == NULL)
 135                 return -1;
 136         bn = (BIGNUM *)*pval;
 137         /* If MSB set in an octet we need a padding byte */
 138         if (BN_num_bits(bn) & 0x7)
 139                 pad = 0;
 140         else
 141                 pad = 1;
 142         if (cont) {
 143                 if (pad)
 144                         *cont++ = 0;
 145                 len = BN_bn2bin(bn, cont);
 146         } else
 147                 len = BN_num_bytes(bn);
 148         return pad + len;
 149 }
 150
 151 static int
 152 bn_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len, int utype,
 153     char *free_cont, const ASN1_ITEM *it)
 154 {
 155         BIGNUM *bn;
 156
 157         if (*pval == NULL) {
 158                 if (bn_new(pval, it) == 0)
 159                         return 0;
 160         }
 161         bn = (BIGNUM *)*pval;
 162         if (!BN_bin2bn(cont, len, bn)) {
 163                 bn_free(pval, it);
 164                 return 0;
 165         }
 166         return 1;
 167 }