dsa_asn1.c revision 277195 
1/* dsa_asn1.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/dsa.h>
62#include <openssl/asn1.h>
63#include <openssl/asn1t.h>
64#include <openssl/bn.h>
65#include <openssl/rand.h>
66#ifdef OPENSSL_FIPS
67#include <openssl/fips.h>
68#endif
69
70
71/* Override the default new methods */
72static int sig_cb(int operation, ASN1_VALUE **pval, const ASN1_ITEM *it)
73{
74	if(operation == ASN1_OP_NEW_PRE) {
75		DSA_SIG *sig;
76		sig = OPENSSL_malloc(sizeof(DSA_SIG));
77		sig->r = NULL;
78		sig->s = NULL;
79		*pval = (ASN1_VALUE *)sig;
80		if(sig) return 2;
81		DSAerr(DSA_F_SIG_CB, ERR_R_MALLOC_FAILURE);
82		return 0;
83	}
84	return 1;
85}
86
87ASN1_SEQUENCE_cb(DSA_SIG, sig_cb) = {
88	ASN1_SIMPLE(DSA_SIG, r, CBIGNUM),
89	ASN1_SIMPLE(DSA_SIG, s, CBIGNUM)
90} ASN1_SEQUENCE_END_cb(DSA_SIG, DSA_SIG)
91
92IMPLEMENT_ASN1_ENCODE_FUNCTIONS_const_fname(DSA_SIG,DSA_SIG,DSA_SIG)
93
94/* Override the default free and new methods */
95static int dsa_cb(int operation, ASN1_VALUE **pval, const ASN1_ITEM *it)
96{
97	if(operation == ASN1_OP_NEW_PRE) {
98		*pval = (ASN1_VALUE *)DSA_new();
99		if(*pval) return 2;
100		return 0;
101	} else if(operation == ASN1_OP_FREE_PRE) {
102		DSA_free((DSA *)*pval);
103		*pval = NULL;
104		return 2;
105	}
106	return 1;
107}
108
109ASN1_SEQUENCE_cb(DSAPrivateKey, dsa_cb) = {
110	ASN1_SIMPLE(DSA, version, LONG),
111	ASN1_SIMPLE(DSA, p, BIGNUM),
112	ASN1_SIMPLE(DSA, q, BIGNUM),
113	ASN1_SIMPLE(DSA, g, BIGNUM),
114	ASN1_SIMPLE(DSA, pub_key, BIGNUM),
115	ASN1_SIMPLE(DSA, priv_key, BIGNUM)
116} ASN1_SEQUENCE_END_cb(DSA, DSAPrivateKey)
117
118IMPLEMENT_ASN1_ENCODE_FUNCTIONS_const_fname(DSA, DSAPrivateKey, DSAPrivateKey)
119
120ASN1_SEQUENCE_cb(DSAparams, dsa_cb) = {
121	ASN1_SIMPLE(DSA, p, BIGNUM),
122	ASN1_SIMPLE(DSA, q, BIGNUM),
123	ASN1_SIMPLE(DSA, g, BIGNUM),
124} ASN1_SEQUENCE_END_cb(DSA, DSAparams)
125
126IMPLEMENT_ASN1_ENCODE_FUNCTIONS_const_fname(DSA, DSAparams, DSAparams)
127
128/* DSA public key is a bit trickier... its effectively a CHOICE type
129 * decided by a field called write_params which can either write out
130 * just the public key as an INTEGER or the parameters and public key
131 * in a SEQUENCE
132 */
133
134ASN1_SEQUENCE(dsa_pub_internal) = {
135	ASN1_SIMPLE(DSA, pub_key, BIGNUM),
136	ASN1_SIMPLE(DSA, p, BIGNUM),
137	ASN1_SIMPLE(DSA, q, BIGNUM),
138	ASN1_SIMPLE(DSA, g, BIGNUM)
139} ASN1_SEQUENCE_END_name(DSA, dsa_pub_internal)
140
141ASN1_CHOICE_cb(DSAPublicKey, dsa_cb) = {
142	ASN1_SIMPLE(DSA, pub_key, BIGNUM),
143	ASN1_EX_COMBINE(0, 0, dsa_pub_internal)
144} ASN1_CHOICE_END_cb(DSA, DSAPublicKey, write_params)
145
146IMPLEMENT_ASN1_ENCODE_FUNCTIONS_const_fname(DSA, DSAPublicKey, DSAPublicKey)
147
148int DSA_sign(int type, const unsigned char *dgst, int dlen, unsigned char *sig,
149	     unsigned int *siglen, DSA *dsa)
150	{
151	DSA_SIG *s;
152#ifdef OPENSSL_FIPS
153	if(FIPS_mode() && !(dsa->flags & DSA_FLAG_NON_FIPS_ALLOW))
154		{
155		DSAerr(DSA_F_DSA_SIGN, DSA_R_OPERATION_NOT_ALLOWED_IN_FIPS_MODE);
156		return 0;
157		}
158#endif
159	RAND_seed(dgst, dlen);
160	s=DSA_do_sign(dgst,dlen,dsa);
161	if (s == NULL)
162		{
163		*siglen=0;
164		return(0);
165		}
166	*siglen=i2d_DSA_SIG(s,&sig);
167	DSA_SIG_free(s);
168	return(1);
169	}
170
171int DSA_size(const DSA *r)
172	{
173	int ret,i;
174	ASN1_INTEGER bs;
175	unsigned char buf[4];	/* 4 bytes looks really small.
176				   However, i2d_ASN1_INTEGER() will not look
177				   beyond the first byte, as long as the second
178				   parameter is NULL. */
179
180	i=BN_num_bits(r->q);
181	bs.length=(i+7)/8;
182	bs.data=buf;
183	bs.type=V_ASN1_INTEGER;
184	/* If the top bit is set the asn1 encoding is 1 larger. */
185	buf[0]=0xff;
186
187	i=i2d_ASN1_INTEGER(&bs,NULL);
188	i+=i; /* r and s */
189	ret=ASN1_object_size(1,i,V_ASN1_SEQUENCE);
190	return(ret);
191	}
192
193/* data has already been hashed (probably with SHA or SHA-1). */
194/* returns
195 *      1: correct signature
196 *      0: incorrect signature
197 *     -1: error
198 */
199int DSA_verify(int type, const unsigned char *dgst, int dgst_len,
200	     const unsigned char *sigbuf, int siglen, DSA *dsa)
201	{
202	DSA_SIG *s;
203	const unsigned char *p = sigbuf;
204	unsigned char *der = NULL;
205	int derlen = -1;
206	int ret=-1;
207
208#ifdef OPENSSL_FIPS
209	if(FIPS_mode() && !(dsa->flags & DSA_FLAG_NON_FIPS_ALLOW))
210		{
211		DSAerr(DSA_F_DSA_VERIFY, DSA_R_OPERATION_NOT_ALLOWED_IN_FIPS_MODE);
212		return 0;
213		}
214#endif
215
216	s = DSA_SIG_new();
217	if (s == NULL) return(ret);
218	if (d2i_DSA_SIG(&s,&p,siglen) == NULL) goto err;
219	/* Ensure signature uses DER and doesn't have trailing garbage */
220	derlen = i2d_DSA_SIG(s, &der);
221	if (derlen != siglen || memcmp(sigbuf, der, derlen))
222		goto err;
223	ret=DSA_do_verify(dgst,dgst_len,s,dsa);
224err:
225	if (derlen > 0)
226		{
227		OPENSSL_cleanse(der, derlen);
228		OPENSSL_free(der);
229		}
230	DSA_SIG_free(s);
231	return(ret);
232	}
233