1/*
2 * Copyright 1999-2016 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the OpenSSL license (the "License").  You may not use
5 * this file except in compliance with the License.  You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10#include <stdio.h>
11#include "internal/cryptlib.h"
12#include "dsa_local.h"
13#include <openssl/asn1.h>
14#include <openssl/asn1t.h>
15#include <openssl/rand.h>
16
17ASN1_SEQUENCE(DSA_SIG) = {
18        ASN1_SIMPLE(DSA_SIG, r, CBIGNUM),
19        ASN1_SIMPLE(DSA_SIG, s, CBIGNUM)
20} static_ASN1_SEQUENCE_END(DSA_SIG)
21
22IMPLEMENT_ASN1_ENCODE_FUNCTIONS_const_fname(DSA_SIG, DSA_SIG, DSA_SIG)
23
24DSA_SIG *DSA_SIG_new(void)
25{
26    DSA_SIG *sig = OPENSSL_zalloc(sizeof(*sig));
27    if (sig == NULL)
28        DSAerr(DSA_F_DSA_SIG_NEW, ERR_R_MALLOC_FAILURE);
29    return sig;
30}
31
32void DSA_SIG_free(DSA_SIG *sig)
33{
34    if (sig == NULL)
35        return;
36    BN_clear_free(sig->r);
37    BN_clear_free(sig->s);
38    OPENSSL_free(sig);
39}
40
41void DSA_SIG_get0(const DSA_SIG *sig, const BIGNUM **pr, const BIGNUM **ps)
42{
43    if (pr != NULL)
44        *pr = sig->r;
45    if (ps != NULL)
46        *ps = sig->s;
47}
48
49int DSA_SIG_set0(DSA_SIG *sig, BIGNUM *r, BIGNUM *s)
50{
51    if (r == NULL || s == NULL)
52        return 0;
53    BN_clear_free(sig->r);
54    BN_clear_free(sig->s);
55    sig->r = r;
56    sig->s = s;
57    return 1;
58}
59
60/* Override the default free and new methods */
61static int dsa_cb(int operation, ASN1_VALUE **pval, const ASN1_ITEM *it,
62                  void *exarg)
63{
64    if (operation == ASN1_OP_NEW_PRE) {
65        *pval = (ASN1_VALUE *)DSA_new();
66        if (*pval != NULL)
67            return 2;
68        return 0;
69    } else if (operation == ASN1_OP_FREE_PRE) {
70        DSA_free((DSA *)*pval);
71        *pval = NULL;
72        return 2;
73    }
74    return 1;
75}
76
77ASN1_SEQUENCE_cb(DSAPrivateKey, dsa_cb) = {
78        ASN1_EMBED(DSA, version, INT32),
79        ASN1_SIMPLE(DSA, p, BIGNUM),
80        ASN1_SIMPLE(DSA, q, BIGNUM),
81        ASN1_SIMPLE(DSA, g, BIGNUM),
82        ASN1_SIMPLE(DSA, pub_key, BIGNUM),
83        ASN1_SIMPLE(DSA, priv_key, CBIGNUM)
84} static_ASN1_SEQUENCE_END_cb(DSA, DSAPrivateKey)
85
86IMPLEMENT_ASN1_ENCODE_FUNCTIONS_const_fname(DSA, DSAPrivateKey, DSAPrivateKey)
87
88ASN1_SEQUENCE_cb(DSAparams, dsa_cb) = {
89        ASN1_SIMPLE(DSA, p, BIGNUM),
90        ASN1_SIMPLE(DSA, q, BIGNUM),
91        ASN1_SIMPLE(DSA, g, BIGNUM),
92} static_ASN1_SEQUENCE_END_cb(DSA, DSAparams)
93
94IMPLEMENT_ASN1_ENCODE_FUNCTIONS_const_fname(DSA, DSAparams, DSAparams)
95
96ASN1_SEQUENCE_cb(DSAPublicKey, dsa_cb) = {
97        ASN1_SIMPLE(DSA, pub_key, BIGNUM),
98        ASN1_SIMPLE(DSA, p, BIGNUM),
99        ASN1_SIMPLE(DSA, q, BIGNUM),
100        ASN1_SIMPLE(DSA, g, BIGNUM)
101} static_ASN1_SEQUENCE_END_cb(DSA, DSAPublicKey)
102
103IMPLEMENT_ASN1_ENCODE_FUNCTIONS_const_fname(DSA, DSAPublicKey, DSAPublicKey)
104
105DSA *DSAparams_dup(DSA *dsa)
106{
107    return ASN1_item_dup(ASN1_ITEM_rptr(DSAparams), dsa);
108}
109
110int DSA_sign(int type, const unsigned char *dgst, int dlen,
111             unsigned char *sig, unsigned int *siglen, DSA *dsa)
112{
113    DSA_SIG *s;
114
115    s = DSA_do_sign(dgst, dlen, dsa);
116    if (s == NULL) {
117        *siglen = 0;
118        return 0;
119    }
120    *siglen = i2d_DSA_SIG(s, &sig);
121    DSA_SIG_free(s);
122    return 1;
123}
124
125/* data has already been hashed (probably with SHA or SHA-1). */
126/*-
127 * returns
128 *      1: correct signature
129 *      0: incorrect signature
130 *     -1: error
131 */
132int DSA_verify(int type, const unsigned char *dgst, int dgst_len,
133               const unsigned char *sigbuf, int siglen, DSA *dsa)
134{
135    DSA_SIG *s;
136    const unsigned char *p = sigbuf;
137    unsigned char *der = NULL;
138    int derlen = -1;
139    int ret = -1;
140
141    s = DSA_SIG_new();
142    if (s == NULL)
143        return ret;
144    if (d2i_DSA_SIG(&s, &p, siglen) == NULL)
145        goto err;
146    /* Ensure signature uses DER and doesn't have trailing garbage */
147    derlen = i2d_DSA_SIG(s, &der);
148    if (derlen != siglen || memcmp(sigbuf, der, derlen))
149        goto err;
150    ret = DSA_do_verify(dgst, dgst_len, s, dsa);
151 err:
152    OPENSSL_clear_free(der, derlen);
153    DSA_SIG_free(s);
154    return ret;
155}
156