1 /*
2 * Copyright 1995-2024 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 "internal/cryptlib.h"
18 #include <openssl/bn.h>
19 #include "dsa_local.h"
20 #include "crypto/dsa.h"
21
dsa_precheck_params(const DSA * dsa,int * ret)22 static int dsa_precheck_params(const DSA *dsa, int *ret)
23 {
24 if (dsa->params.p == NULL || dsa->params.q == NULL) {
25 ERR_raise(ERR_LIB_DSA, DSA_R_BAD_FFC_PARAMETERS);
26 *ret = FFC_CHECK_INVALID_PQ;
27 return 0;
28 }
29
30 if (BN_num_bits(dsa->params.p) > OPENSSL_DSA_MAX_MODULUS_BITS) {
31 ERR_raise(ERR_LIB_DSA, DSA_R_MODULUS_TOO_LARGE);
32 *ret = FFC_CHECK_INVALID_PQ;
33 return 0;
34 }
35
36 if (BN_num_bits(dsa->params.q) >= BN_num_bits(dsa->params.p)) {
37 ERR_raise(ERR_LIB_DSA, DSA_R_BAD_Q_VALUE);
38 *ret = FFC_CHECK_INVALID_PQ;
39 return 0;
40 }
41
42 return 1;
43 }
44
ossl_dsa_check_params(const DSA * dsa,int checktype,int * ret)45 int ossl_dsa_check_params(const DSA *dsa, int checktype, int *ret)
46 {
47 if (!dsa_precheck_params(dsa, ret))
48 return 0;
49
50 if (checktype == OSSL_KEYMGMT_VALIDATE_QUICK_CHECK)
51 return ossl_ffc_params_simple_validate(dsa->libctx, &dsa->params,
52 FFC_PARAM_TYPE_DSA, ret);
53 else
54 /*
55 * Do full FFC domain params validation according to FIPS-186-4
56 * - always in FIPS_MODULE
57 * - only if possible (i.e., seed is set) in default provider
58 */
59 return ossl_ffc_params_full_validate(dsa->libctx, &dsa->params,
60 FFC_PARAM_TYPE_DSA, ret);
61 }
62
63 /*
64 * See SP800-56Ar3 Section 5.6.2.3.1 : FFC Full public key validation.
65 */
ossl_dsa_check_pub_key(const DSA * dsa,const BIGNUM * pub_key,int * ret)66 int ossl_dsa_check_pub_key(const DSA *dsa, const BIGNUM *pub_key, int *ret)
67 {
68 if (!dsa_precheck_params(dsa, ret))
69 return 0;
70
71 return ossl_ffc_validate_public_key(&dsa->params, pub_key, ret)
72 && *ret == 0;
73 }
74
75 /*
76 * See SP800-56Ar3 Section 5.6.2.3.1 : FFC Partial public key validation.
77 * To only be used with ephemeral FFC public keys generated using the approved
78 * safe-prime groups.
79 */
ossl_dsa_check_pub_key_partial(const DSA * dsa,const BIGNUM * pub_key,int * ret)80 int ossl_dsa_check_pub_key_partial(const DSA *dsa, const BIGNUM *pub_key, int *ret)
81 {
82 if (!dsa_precheck_params(dsa, ret))
83 return 0;
84
85 return ossl_ffc_validate_public_key_partial(&dsa->params, pub_key, ret)
86 && *ret == 0;
87 }
88
ossl_dsa_check_priv_key(const DSA * dsa,const BIGNUM * priv_key,int * ret)89 int ossl_dsa_check_priv_key(const DSA *dsa, const BIGNUM *priv_key, int *ret)
90 {
91 *ret = 0;
92
93 if (!dsa_precheck_params(dsa, ret))
94 return 0;
95
96 return ossl_ffc_validate_private_key(dsa->params.q, priv_key, ret);
97 }
98
99 /*
100 * FFC pairwise check from SP800-56A R3.
101 * Section 5.6.2.1.4 Owner Assurance of Pair-wise Consistency
102 */
ossl_dsa_check_pairwise(const DSA * dsa)103 int ossl_dsa_check_pairwise(const DSA *dsa)
104 {
105 int ret = 0;
106 BN_CTX *ctx = NULL;
107 BIGNUM *pub_key = NULL;
108
109 if (!dsa_precheck_params(dsa, &ret))
110 return 0;
111
112 if (dsa->params.g == NULL
113 || dsa->priv_key == NULL
114 || dsa->pub_key == NULL)
115 return 0;
116
117 ctx = BN_CTX_new_ex(dsa->libctx);
118 if (ctx == NULL)
119 goto err;
120 pub_key = BN_new();
121 if (pub_key == NULL)
122 goto err;
123
124 /* recalculate the public key = (g ^ priv) mod p */
125 if (!ossl_dsa_generate_public_key(ctx, dsa, dsa->priv_key, pub_key))
126 goto err;
127 /* check it matches the existing public_key */
128 ret = BN_cmp(pub_key, dsa->pub_key) == 0;
129 err:
130 BN_free(pub_key);
131 BN_CTX_free(ctx);
132 return ret;
133 }
134
