1 /*
2 * Copyright 1995-2021 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (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 /*
11 * DSA low level APIs are deprecated for public use, but still ok for
12 * internal use.
13 */
14 #include "internal/deprecated.h"
15
16 #include <stdio.h>
17 #include <time.h>
18 #include "internal/cryptlib.h"
19 #include <openssl/bn.h>
20 #include <openssl/self_test.h>
21 #include "prov/providercommon.h"
22 #include "crypto/dsa.h"
23 #include "dsa_local.h"
24
25 #ifdef FIPS_MODULE
26 # define MIN_STRENGTH 112
27 #else
28 # define MIN_STRENGTH 80
29 #endif
30
31 static int dsa_keygen(DSA *dsa, int pairwise_test);
32 static int dsa_keygen_pairwise_test(DSA *dsa, OSSL_CALLBACK *cb, void *cbarg);
33
DSA_generate_key(DSA * dsa)34 int DSA_generate_key(DSA *dsa)
35 {
36 #ifndef FIPS_MODULE
37 if (dsa->meth->dsa_keygen != NULL)
38 return dsa->meth->dsa_keygen(dsa);
39 #endif
40 return dsa_keygen(dsa, 0);
41 }
42
ossl_dsa_generate_public_key(BN_CTX * ctx,const DSA * dsa,const BIGNUM * priv_key,BIGNUM * pub_key)43 int ossl_dsa_generate_public_key(BN_CTX *ctx, const DSA *dsa,
44 const BIGNUM *priv_key, BIGNUM *pub_key)
45 {
46 int ret = 0;
47 BIGNUM *prk = BN_new();
48
49 if (prk == NULL)
50 return 0;
51 BN_with_flags(prk, priv_key, BN_FLG_CONSTTIME);
52
53 /* pub_key = g ^ priv_key mod p */
54 if (!BN_mod_exp(pub_key, dsa->params.g, prk, dsa->params.p, ctx))
55 goto err;
56 ret = 1;
57 err:
58 BN_clear_free(prk);
59 return ret;
60 }
61
dsa_keygen(DSA * dsa,int pairwise_test)62 static int dsa_keygen(DSA *dsa, int pairwise_test)
63 {
64 int ok = 0;
65 BN_CTX *ctx = NULL;
66 BIGNUM *pub_key = NULL, *priv_key = NULL;
67
68 if ((ctx = BN_CTX_new_ex(dsa->libctx)) == NULL)
69 goto err;
70
71 if (dsa->priv_key == NULL) {
72 if ((priv_key = BN_secure_new()) == NULL)
73 goto err;
74 } else {
75 priv_key = dsa->priv_key;
76 }
77
78 /* Do a partial check for invalid p, q, g */
79 if (!ossl_ffc_params_simple_validate(dsa->libctx, &dsa->params,
80 FFC_PARAM_TYPE_DSA, NULL))
81 goto err;
82
83 /*
84 * For FFC FIPS 186-4 keygen
85 * security strength s = 112,
86 * Max Private key size N = len(q)
87 */
88 if (!ossl_ffc_generate_private_key(ctx, &dsa->params,
89 BN_num_bits(dsa->params.q),
90 MIN_STRENGTH, priv_key))
91 goto err;
92
93 if (dsa->pub_key == NULL) {
94 if ((pub_key = BN_new()) == NULL)
95 goto err;
96 } else {
97 pub_key = dsa->pub_key;
98 }
99
100 if (!ossl_dsa_generate_public_key(ctx, dsa, priv_key, pub_key))
101 goto err;
102
103 dsa->priv_key = priv_key;
104 dsa->pub_key = pub_key;
105
106 #ifdef FIPS_MODULE
107 pairwise_test = 1;
108 #endif /* FIPS_MODULE */
109
110 ok = 1;
111 if (pairwise_test) {
112 OSSL_CALLBACK *cb = NULL;
113 void *cbarg = NULL;
114
115 OSSL_SELF_TEST_get_callback(dsa->libctx, &cb, &cbarg);
116 ok = dsa_keygen_pairwise_test(dsa, cb, cbarg);
117 if (!ok) {
118 ossl_set_error_state(OSSL_SELF_TEST_TYPE_PCT);
119 BN_free(dsa->pub_key);
120 BN_clear_free(dsa->priv_key);
121 dsa->pub_key = NULL;
122 dsa->priv_key = NULL;
123 BN_CTX_free(ctx);
124 return ok;
125 }
126 }
127 dsa->dirty_cnt++;
128
129 err:
130 if (pub_key != dsa->pub_key)
131 BN_free(pub_key);
132 if (priv_key != dsa->priv_key)
133 BN_free(priv_key);
134 BN_CTX_free(ctx);
135
136 return ok;
137 }
138
139 /*
140 * FIPS 140-2 IG 9.9 AS09.33
141 * Perform a sign/verify operation.
142 */
dsa_keygen_pairwise_test(DSA * dsa,OSSL_CALLBACK * cb,void * cbarg)143 static int dsa_keygen_pairwise_test(DSA *dsa, OSSL_CALLBACK *cb, void *cbarg)
144 {
145 int ret = 0;
146 unsigned char dgst[16] = {0};
147 unsigned int dgst_len = (unsigned int)sizeof(dgst);
148 DSA_SIG *sig = NULL;
149 OSSL_SELF_TEST *st = NULL;
150
151 st = OSSL_SELF_TEST_new(cb, cbarg);
152 if (st == NULL)
153 goto err;
154
155 OSSL_SELF_TEST_onbegin(st, OSSL_SELF_TEST_TYPE_PCT,
156 OSSL_SELF_TEST_DESC_PCT_DSA);
157
158 sig = DSA_do_sign(dgst, (int)dgst_len, dsa);
159 if (sig == NULL)
160 goto err;
161
162 OSSL_SELF_TEST_oncorrupt_byte(st, dgst);
163
164 if (DSA_do_verify(dgst, dgst_len, sig, dsa) != 1)
165 goto err;
166
167 ret = 1;
168 err:
169 OSSL_SELF_TEST_onend(st, ret);
170 OSSL_SELF_TEST_free(st);
171 DSA_SIG_free(sig);
172 return ret;
173 }
174