xref: /openssl/crypto/dh/dh_backend.c (revision da1c088f)
1 /*
2  * Copyright 2020-2023 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 
dh_ffc_params_fromdata(DH * dh,const OSSL_PARAM params[])31 static int dh_ffc_params_fromdata(DH *dh, const OSSL_PARAM params[])
32 {
33     int ret;
34     FFC_PARAMS *ffc = ossl_dh_get0_params(dh);
35 
36     ret = ossl_ffc_params_fromdata(ffc, params);
37     if (ret)
38         ossl_dh_cache_named_group(dh); /* This increments dh->dirty_cnt */
39     return ret;
40 }
41 
ossl_dh_params_fromdata(DH * dh,const OSSL_PARAM params[])42 int ossl_dh_params_fromdata(DH *dh, const OSSL_PARAM params[])
43 {
44     const OSSL_PARAM *param_priv_len;
45     long priv_len;
46 
47     if (!dh_ffc_params_fromdata(dh, params))
48         return 0;
49 
50     param_priv_len =
51         OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_DH_PRIV_LEN);
52     if (param_priv_len != NULL
53         && (!OSSL_PARAM_get_long(param_priv_len, &priv_len)
54             || !DH_set_length(dh, priv_len)))
55         return 0;
56 
57     return 1;
58 }
59 
ossl_dh_key_fromdata(DH * dh,const OSSL_PARAM params[],int include_private)60 int ossl_dh_key_fromdata(DH *dh, const OSSL_PARAM params[], int include_private)
61 {
62     const OSSL_PARAM *param_priv_key, *param_pub_key;
63     BIGNUM *priv_key = NULL, *pub_key = NULL;
64 
65     if (dh == NULL)
66         return 0;
67 
68     param_priv_key = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_PRIV_KEY);
69     param_pub_key = OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_PUB_KEY);
70 
71     if (include_private
72         && param_priv_key != NULL
73         && !OSSL_PARAM_get_BN(param_priv_key, &priv_key))
74         goto err;
75 
76     if (param_pub_key != NULL
77         && !OSSL_PARAM_get_BN(param_pub_key, &pub_key))
78         goto err;
79 
80     if (!DH_set0_key(dh, pub_key, priv_key))
81         goto err;
82 
83     return 1;
84 
85  err:
86     BN_clear_free(priv_key);
87     BN_free(pub_key);
88     return 0;
89 }
90 
ossl_dh_params_todata(DH * dh,OSSL_PARAM_BLD * bld,OSSL_PARAM params[])91 int ossl_dh_params_todata(DH *dh, OSSL_PARAM_BLD *bld, OSSL_PARAM params[])
92 {
93     long l = DH_get_length(dh);
94 
95     if (!ossl_ffc_params_todata(ossl_dh_get0_params(dh), bld, params))
96         return 0;
97     if (l > 0
98         && !ossl_param_build_set_long(bld, params, OSSL_PKEY_PARAM_DH_PRIV_LEN, l))
99         return 0;
100     return 1;
101 }
102 
ossl_dh_key_todata(DH * dh,OSSL_PARAM_BLD * bld,OSSL_PARAM params[],int include_private)103 int ossl_dh_key_todata(DH *dh, OSSL_PARAM_BLD *bld, OSSL_PARAM params[],
104                        int include_private)
105 {
106     const BIGNUM *priv = NULL, *pub = NULL;
107 
108     if (dh == NULL)
109         return 0;
110 
111     DH_get0_key(dh, &pub, &priv);
112     if (priv != NULL
113         && include_private
114         && !ossl_param_build_set_bn(bld, params, OSSL_PKEY_PARAM_PRIV_KEY, priv))
115         return 0;
116     if (pub != NULL
117         && !ossl_param_build_set_bn(bld, params, OSSL_PKEY_PARAM_PUB_KEY, pub))
118         return 0;
119 
120     return 1;
121 }
122 
ossl_dh_is_foreign(const DH * dh)123 int ossl_dh_is_foreign(const DH *dh)
124 {
125 #ifndef FIPS_MODULE
126     if (dh->engine != NULL || ossl_dh_get_method(dh) != DH_OpenSSL())
127         return 1;
128 #endif
129     return 0;
130 }
131 
dh_bn_dup_check(BIGNUM ** out,const BIGNUM * f)132 static ossl_inline int dh_bn_dup_check(BIGNUM **out, const BIGNUM *f)
133 {
134     if (f != NULL && (*out = BN_dup(f)) == NULL)
135         return 0;
136     return 1;
137 }
138 
ossl_dh_dup(const DH * dh,int selection)139 DH *ossl_dh_dup(const DH *dh, int selection)
140 {
141     DH *dupkey = NULL;
142 
143     /* Do not try to duplicate foreign DH keys */
144     if (ossl_dh_is_foreign(dh))
145         return NULL;
146 
147     if ((dupkey = ossl_dh_new_ex(dh->libctx)) == NULL)
148         return NULL;
149 
150     dupkey->length = DH_get_length(dh);
151     if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0
152         && !ossl_ffc_params_copy(&dupkey->params, &dh->params))
153         goto err;
154 
155     dupkey->flags = dh->flags;
156 
157     if ((selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) != 0
158         && ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) == 0
159             || !dh_bn_dup_check(&dupkey->pub_key, dh->pub_key)))
160         goto err;
161 
162     if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0
163         && ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) == 0
164             || !dh_bn_dup_check(&dupkey->priv_key, dh->priv_key)))
165         goto err;
166 
167 #ifndef FIPS_MODULE
168     if (!CRYPTO_dup_ex_data(CRYPTO_EX_INDEX_DH,
169                             &dupkey->ex_data, &dh->ex_data))
170         goto err;
171 #endif
172 
173     return dupkey;
174 
175  err:
176     DH_free(dupkey);
177     return NULL;
178 }
179 
180 #ifndef FIPS_MODULE
ossl_dh_key_from_pkcs8(const PKCS8_PRIV_KEY_INFO * p8inf,OSSL_LIB_CTX * libctx,const char * propq)181 DH *ossl_dh_key_from_pkcs8(const PKCS8_PRIV_KEY_INFO *p8inf,
182                            OSSL_LIB_CTX *libctx, const char *propq)
183 {
184     const unsigned char *p, *pm;
185     int pklen, pmlen;
186     int ptype;
187     const void *pval;
188     const ASN1_STRING *pstr;
189     const X509_ALGOR *palg;
190     BIGNUM *privkey_bn = NULL;
191     ASN1_INTEGER *privkey = NULL;
192     DH *dh = NULL;
193 
194     if (!PKCS8_pkey_get0(NULL, &p, &pklen, &palg, p8inf))
195         return 0;
196 
197     X509_ALGOR_get0(NULL, &ptype, &pval, palg);
198 
199     if (ptype != V_ASN1_SEQUENCE)
200         goto decerr;
201     if ((privkey = d2i_ASN1_INTEGER(NULL, &p, pklen)) == NULL)
202         goto decerr;
203 
204     pstr = pval;
205     pm = pstr->data;
206     pmlen = pstr->length;
207     switch (OBJ_obj2nid(palg->algorithm)) {
208     case NID_dhKeyAgreement:
209         dh = d2i_DHparams(NULL, &pm, pmlen);
210         break;
211     case NID_dhpublicnumber:
212         dh = d2i_DHxparams(NULL, &pm, pmlen);
213         break;
214     default:
215         goto decerr;
216     }
217     if (dh == NULL)
218         goto decerr;
219 
220     /* We have parameters now set private key */
221     if ((privkey_bn = BN_secure_new()) == NULL
222         || !ASN1_INTEGER_to_BN(privkey, privkey_bn)) {
223         ERR_raise(ERR_LIB_DH, DH_R_BN_ERROR);
224         BN_clear_free(privkey_bn);
225         goto dherr;
226     }
227     if (!DH_set0_key(dh, NULL, privkey_bn))
228         goto dherr;
229     /* Calculate public key, increments dirty_cnt */
230     if (!DH_generate_key(dh))
231         goto dherr;
232 
233     goto done;
234 
235  decerr:
236     ERR_raise(ERR_LIB_DH, EVP_R_DECODE_ERROR);
237  dherr:
238     DH_free(dh);
239     dh = NULL;
240  done:
241     ASN1_STRING_clear_free(privkey);
242     return dh;
243 }
244 #endif
245