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      1 /* x_bignum.c */
      2 /* Written by Dr Stephen N Henson (steve (at) 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 (at) 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 (at) cryptsoft.com).  This product includes software written by Tim
     55  * Hudson (tjh (at) cryptsoft.com).
     56  *
     57  */
     58 
     59 #include <stdio.h>
     60 #include "cryptlib.h"
     61 #include <openssl/asn1t.h>
     62 #include <openssl/bn.h>
     63 
     64 /* Custom primitive type for BIGNUM handling. This reads in an ASN1_INTEGER as a
     65  * BIGNUM directly. Currently it ignores the sign which isn't a problem since all
     66  * BIGNUMs used are non negative and anything that looks negative is normally due
     67  * to an encoding error.
     68  */
     69 
     70 #define BN_SENSITIVE	1
     71 
     72 static int bn_new(ASN1_VALUE **pval, const ASN1_ITEM *it);
     73 static void bn_free(ASN1_VALUE **pval, const ASN1_ITEM *it);
     74 
     75 static int bn_i2c(ASN1_VALUE **pval, unsigned char *cont, int *putype, const ASN1_ITEM *it);
     76 static int bn_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len, int utype, char *free_cont, const ASN1_ITEM *it);
     77 
     78 static ASN1_PRIMITIVE_FUNCS bignum_pf = {
     79 	NULL, 0,
     80 	bn_new,
     81 	bn_free,
     82 	0,
     83 	bn_c2i,
     84 	bn_i2c
     85 };
     86 
     87 ASN1_ITEM_start(BIGNUM)
     88 	ASN1_ITYPE_PRIMITIVE, V_ASN1_INTEGER, NULL, 0, &bignum_pf, 0, "BIGNUM"
     89 ASN1_ITEM_end(BIGNUM)
     90 
     91 ASN1_ITEM_start(CBIGNUM)
     92 	ASN1_ITYPE_PRIMITIVE, V_ASN1_INTEGER, NULL, 0, &bignum_pf, BN_SENSITIVE, "BIGNUM"
     93 ASN1_ITEM_end(CBIGNUM)
     94 
     95 static int bn_new(ASN1_VALUE **pval, const ASN1_ITEM *it)
     96 {
     97 	*pval = (ASN1_VALUE *)BN_new();
     98 	if(*pval) return 1;
     99 	else return 0;
    100 }
    101 
    102 static void bn_free(ASN1_VALUE **pval, const ASN1_ITEM *it)
    103 {
    104 	if(!*pval) return;
    105 	if(it->size & BN_SENSITIVE) BN_clear_free((BIGNUM *)*pval);
    106 	else BN_free((BIGNUM *)*pval);
    107 	*pval = NULL;
    108 }
    109 
    110 static int bn_i2c(ASN1_VALUE **pval, unsigned char *cont, int *putype, const ASN1_ITEM *it)
    111 {
    112 	BIGNUM *bn;
    113 	int pad;
    114 	if(!*pval) return -1;
    115 	bn = (BIGNUM *)*pval;
    116 	/* If MSB set in an octet we need a padding byte */
    117 	if(BN_num_bits(bn) & 0x7) pad = 0;
    118 	else pad = 1;
    119 	if(cont) {
    120 		if(pad) *cont++ = 0;
    121 		BN_bn2bin(bn, cont);
    122 	}
    123 	return pad + BN_num_bytes(bn);
    124 }
    125 
    126 static int bn_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len,
    127 		  int utype, char *free_cont, const ASN1_ITEM *it)
    128 {
    129 	BIGNUM *bn;
    130 	if(!*pval) bn_new(pval, it);
    131 	bn  = (BIGNUM *)*pval;
    132 	if(!BN_bin2bn(cont, len, bn)) {
    133 		bn_free(pval, it);
    134 		return 0;
    135 	}
    136 	return 1;
    137 }
    138 
    139 
    140