1 /* x_bignum.c */
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 #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 }