1/*
2 * Copyright 2020-2022 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 * DH low level APIs are deprecated for public use, but still ok for
12 * internal use.
13 */
14#include "internal/deprecated.h"
15
16#include <openssl/err.h>
17#include <openssl/core_names.h>
18#ifndef FIPS_MODULE
19# include <openssl/x509.h>
20#endif
21#include "internal/param_build_set.h"
22#include "crypto/dh.h"
23#include "dh_local.h"
24
25/*
26 * The intention with the "backend" source file is to offer backend functions
27 * for legacy backends (EVP_PKEY_ASN1_METHOD and EVP_PKEY_METHOD) and provider
28 * implementations alike.
29 */
30
31static int dh_ffc_params_fromdata(DH *dh, const OSSL_PARAM params[])
32{
33    int ret;
34    FFC_PARAMS *ffc;
35
36    if (dh == NULL)
37        return 0;
38    ffc = ossl_dh_get0_params(dh);
39    if (ffc == NULL)
40        return 0;
41
42    ret = ossl_ffc_params_fromdata(ffc, params);
43    if (ret)
44        ossl_dh_cache_named_group(dh); /* This increments dh->dirty_cnt */
45    return ret;
46}
47
48int ossl_dh_params_fromdata(DH *dh, const OSSL_PARAM params[])
49{
50    const OSSL_PARAM *param_priv_len;
51    long priv_len;
52
53    if (!dh_ffc_params_fromdata(dh, params))
54        return 0;
55
56    param_priv_len =
57        OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_DH_PRIV_LEN);
58    if (param_priv_len != NULL
59        && (!OSSL_PARAM_get_long(param_priv_len, &priv_len)
60            || !DH_set_length(dh, priv_len)))
61        return 0;
62
63    return 1;
64}
65
66int ossl_dh_key_fromdata(DH *dh, const OSSL_PARAM params[], int include_private)
67{
68    const OSSL_PARAM *param_priv_key, *param_pub_key;
69    BIGNUM *priv_key = NULL, *pub_key = NULL;
70
71    if (dh == NULL)
72        return 0;
73
74    param_priv_key = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_PRIV_KEY);
75    param_pub_key = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_PUB_KEY);
76
77    if (include_private
78        && param_priv_key != NULL
79        && !OSSL_PARAM_get_BN(param_priv_key, &priv_key))
80        goto err;
81
82    if (param_pub_key != NULL
83        && !OSSL_PARAM_get_BN(param_pub_key, &pub_key))
84        goto err;
85
86    if (!DH_set0_key(dh, pub_key, priv_key))
87        goto err;
88
89    return 1;
90
91 err:
92    BN_clear_free(priv_key);
93    BN_free(pub_key);
94    return 0;
95}
96
97int ossl_dh_params_todata(DH *dh, OSSL_PARAM_BLD *bld, OSSL_PARAM params[])
98{
99    long l = DH_get_length(dh);
100
101    if (!ossl_ffc_params_todata(ossl_dh_get0_params(dh), bld, params))
102        return 0;
103    if (l > 0
104        && !ossl_param_build_set_long(bld, params, OSSL_PKEY_PARAM_DH_PRIV_LEN, l))
105        return 0;
106    return 1;
107}
108
109int ossl_dh_key_todata(DH *dh, OSSL_PARAM_BLD *bld, OSSL_PARAM params[],
110                       int include_private)
111{
112    const BIGNUM *priv = NULL, *pub = NULL;
113
114    if (dh == NULL)
115        return 0;
116
117    DH_get0_key(dh, &pub, &priv);
118    if (priv != NULL
119        && include_private
120        && !ossl_param_build_set_bn(bld, params, OSSL_PKEY_PARAM_PRIV_KEY, priv))
121        return 0;
122    if (pub != NULL
123        && !ossl_param_build_set_bn(bld, params, OSSL_PKEY_PARAM_PUB_KEY, pub))
124        return 0;
125
126    return 1;
127}
128
129int ossl_dh_is_foreign(const DH *dh)
130{
131#ifndef FIPS_MODULE
132    if (dh->engine != NULL || ossl_dh_get_method(dh) != DH_OpenSSL())
133        return 1;
134#endif
135    return 0;
136}
137
138static ossl_inline int dh_bn_dup_check(BIGNUM **out, const BIGNUM *f)
139{
140    if (f != NULL && (*out = BN_dup(f)) == NULL)
141        return 0;
142    return 1;
143}
144
145DH *ossl_dh_dup(const DH *dh, int selection)
146{
147    DH *dupkey = NULL;
148
149    /* Do not try to duplicate foreign DH keys */
150    if (ossl_dh_is_foreign(dh))
151        return NULL;
152
153    if ((dupkey = ossl_dh_new_ex(dh->libctx)) == NULL)
154        return NULL;
155
156    dupkey->length = DH_get_length(dh);
157    if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0
158        && !ossl_ffc_params_copy(&dupkey->params, &dh->params))
159        goto err;
160
161    dupkey->flags = dh->flags;
162
163    if ((selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) != 0
164        && ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) == 0
165            || !dh_bn_dup_check(&dupkey->pub_key, dh->pub_key)))
166        goto err;
167
168    if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0
169        && ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) == 0
170            || !dh_bn_dup_check(&dupkey->priv_key, dh->priv_key)))
171        goto err;
172
173#ifndef FIPS_MODULE
174    if (!CRYPTO_dup_ex_data(CRYPTO_EX_INDEX_DH,
175                            &dupkey->ex_data, &dh->ex_data))
176        goto err;
177#endif
178
179    return dupkey;
180
181 err:
182    DH_free(dupkey);
183    return NULL;
184}
185
186#ifndef FIPS_MODULE
187DH *ossl_dh_key_from_pkcs8(const PKCS8_PRIV_KEY_INFO *p8inf,
188                           OSSL_LIB_CTX *libctx, const char *propq)
189{
190    const unsigned char *p, *pm;
191    int pklen, pmlen;
192    int ptype;
193    const void *pval;
194    const ASN1_STRING *pstr;
195    const X509_ALGOR *palg;
196    BIGNUM *privkey_bn = NULL;
197    ASN1_INTEGER *privkey = NULL;
198    DH *dh = NULL;
199
200    if (!PKCS8_pkey_get0(NULL, &p, &pklen, &palg, p8inf))
201        return 0;
202
203    X509_ALGOR_get0(NULL, &ptype, &pval, palg);
204
205    if (ptype != V_ASN1_SEQUENCE)
206        goto decerr;
207    if ((privkey = d2i_ASN1_INTEGER(NULL, &p, pklen)) == NULL)
208        goto decerr;
209
210    pstr = pval;
211    pm = pstr->data;
212    pmlen = pstr->length;
213    switch (OBJ_obj2nid(palg->algorithm)) {
214    case NID_dhKeyAgreement:
215        dh = d2i_DHparams(NULL, &pm, pmlen);
216        break;
217    case NID_dhpublicnumber:
218        dh = d2i_DHxparams(NULL, &pm, pmlen);
219        break;
220    default:
221        goto decerr;
222    }
223    if (dh == NULL)
224        goto decerr;
225
226    /* We have parameters now set private key */
227    if ((privkey_bn = BN_secure_new()) == NULL
228        || !ASN1_INTEGER_to_BN(privkey, privkey_bn)) {
229        ERR_raise(ERR_LIB_DH, DH_R_BN_ERROR);
230        BN_clear_free(privkey_bn);
231        goto dherr;
232    }
233    if (!DH_set0_key(dh, NULL, privkey_bn))
234        goto dherr;
235    /* Calculate public key, increments dirty_cnt */
236    if (!DH_generate_key(dh))
237        goto dherr;
238
239    goto done;
240
241 decerr:
242    ERR_raise(ERR_LIB_DH, EVP_R_DECODE_ERROR);
243 dherr:
244    DH_free(dh);
245    dh = NULL;
246 done:
247    ASN1_STRING_clear_free(privkey);
248    return dh;
249}
250#endif
251