x_bignum.c revision 296465 
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 "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
74static int bn_new(ASN1_VALUE **pval, const ASN1_ITEM *it);
75static void bn_free(ASN1_VALUE **pval, const ASN1_ITEM *it);
76
77static int bn_i2c(ASN1_VALUE **pval, unsigned char *cont, int *putype,
78                  const ASN1_ITEM *it);
79static int bn_c2i(ASN1_VALUE **pval, const unsigned char *cont, int len,
80                  int utype, char *free_cont, const ASN1_ITEM *it);
81
82static ASN1_PRIMITIVE_FUNCS bignum_pf = {
83    NULL, 0,
84    bn_new,
85    bn_free,
86    0,
87    bn_c2i,
88    bn_i2c
89};
90
91ASN1_ITEM_start(BIGNUM)
92        ASN1_ITYPE_PRIMITIVE, V_ASN1_INTEGER, NULL, 0, &bignum_pf, 0, "BIGNUM"
93ASN1_ITEM_end(BIGNUM)
94
95ASN1_ITEM_start(CBIGNUM)
96        ASN1_ITYPE_PRIMITIVE, V_ASN1_INTEGER, NULL, 0, &bignum_pf, BN_SENSITIVE, "BIGNUM"
97ASN1_ITEM_end(CBIGNUM)
98
99static 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
108static 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
119static 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
140static 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}
153