1  /*
2   * Copyright 2020-2021 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 <openssl/core_names.h>
17  #include <openssl/err.h>
18  #ifndef FIPS_MODULE
19  # include <openssl/x509.h>
20  #endif
21  #include "crypto/dsa.h"
22  #include "dsa_local.h"
23  
24  /*
25   * The intention with the "backend" source file is to offer backend support
26   * for legacy backends (EVP_PKEY_ASN1_METHOD and EVP_PKEY_METHOD) and provider
27   * implementations alike.
28   */
29  
ossl_dsa_key_fromdata(DSA * dsa,const OSSL_PARAM params[])30  int ossl_dsa_key_fromdata(DSA *dsa, const OSSL_PARAM params[])
31  {
32      const OSSL_PARAM *param_priv_key, *param_pub_key;
33      BIGNUM *priv_key = NULL, *pub_key = NULL;
34  
35      if (dsa == NULL)
36          return 0;
37  
38      param_priv_key =
39          OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_PRIV_KEY);
40      param_pub_key =
41          OSSL_PARAM_locate_const(params, OSSL_PKEY_PARAM_PUB_KEY);
42  
43      /* It's ok if neither half is present */
44      if (param_priv_key == NULL && param_pub_key == NULL)
45          return 1;
46  
47      if (param_pub_key != NULL && !OSSL_PARAM_get_BN(param_pub_key, &pub_key))
48          goto err;
49      if (param_priv_key != NULL && !OSSL_PARAM_get_BN(param_priv_key, &priv_key))
50          goto err;
51  
52      if (!DSA_set0_key(dsa, pub_key, priv_key))
53          goto err;
54  
55      return 1;
56  
57   err:
58      BN_clear_free(priv_key);
59      BN_free(pub_key);
60      return 0;
61  }
62  
ossl_dsa_is_foreign(const DSA * dsa)63  int ossl_dsa_is_foreign(const DSA *dsa)
64  {
65  #ifndef FIPS_MODULE
66      if (dsa->engine != NULL || DSA_get_method((DSA *)dsa) != DSA_OpenSSL())
67          return 1;
68  #endif
69      return 0;
70  }
71  
dsa_bn_dup_check(BIGNUM ** out,const BIGNUM * f)72  static ossl_inline int dsa_bn_dup_check(BIGNUM **out, const BIGNUM *f)
73  {
74      if (f != NULL && (*out = BN_dup(f)) == NULL)
75          return 0;
76      return 1;
77  }
78  
ossl_dsa_dup(const DSA * dsa,int selection)79  DSA *ossl_dsa_dup(const DSA *dsa, int selection)
80  {
81      DSA *dupkey = NULL;
82  
83      /* Do not try to duplicate foreign DSA keys */
84      if (ossl_dsa_is_foreign(dsa))
85          return NULL;
86  
87      if ((dupkey = ossl_dsa_new(dsa->libctx)) == NULL)
88          return NULL;
89  
90      if ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) != 0
91          && !ossl_ffc_params_copy(&dupkey->params, &dsa->params))
92          goto err;
93  
94      dupkey->flags = dsa->flags;
95  
96      if ((selection & OSSL_KEYMGMT_SELECT_PUBLIC_KEY) != 0
97          && ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) == 0
98              || !dsa_bn_dup_check(&dupkey->pub_key, dsa->pub_key)))
99          goto err;
100  
101      if ((selection & OSSL_KEYMGMT_SELECT_PRIVATE_KEY) != 0
102          && ((selection & OSSL_KEYMGMT_SELECT_DOMAIN_PARAMETERS) == 0
103              || !dsa_bn_dup_check(&dupkey->priv_key, dsa->priv_key)))
104          goto err;
105  
106  #ifndef FIPS_MODULE
107      if (!CRYPTO_dup_ex_data(CRYPTO_EX_INDEX_DSA,
108                              &dupkey->ex_data, &dsa->ex_data))
109          goto err;
110  #endif
111  
112      return dupkey;
113  
114   err:
115      DSA_free(dupkey);
116      return NULL;
117  }
118  
119  #ifndef FIPS_MODULE
ossl_dsa_key_from_pkcs8(const PKCS8_PRIV_KEY_INFO * p8inf,OSSL_LIB_CTX * libctx,const char * propq)120  DSA *ossl_dsa_key_from_pkcs8(const PKCS8_PRIV_KEY_INFO *p8inf,
121                               OSSL_LIB_CTX *libctx, const char *propq)
122  {
123      const unsigned char *p, *pm;
124      int pklen, pmlen;
125      int ptype;
126      const void *pval;
127      const ASN1_STRING *pstr;
128      const X509_ALGOR *palg;
129      ASN1_INTEGER *privkey = NULL;
130      const BIGNUM *dsa_p, *dsa_g;
131      BIGNUM *dsa_pubkey = NULL, *dsa_privkey = NULL;
132      BN_CTX *ctx = NULL;
133  
134      DSA *dsa = NULL;
135  
136      if (!PKCS8_pkey_get0(NULL, &p, &pklen, &palg, p8inf))
137          return 0;
138      X509_ALGOR_get0(NULL, &ptype, &pval, palg);
139  
140      if ((privkey = d2i_ASN1_INTEGER(NULL, &p, pklen)) == NULL)
141          goto decerr;
142      if (privkey->type == V_ASN1_NEG_INTEGER || ptype != V_ASN1_SEQUENCE)
143          goto decerr;
144  
145      pstr = pval;
146      pm = pstr->data;
147      pmlen = pstr->length;
148      if ((dsa = d2i_DSAparams(NULL, &pm, pmlen)) == NULL)
149          goto decerr;
150      /* We have parameters now set private key */
151      if ((dsa_privkey = BN_secure_new()) == NULL
152          || !ASN1_INTEGER_to_BN(privkey, dsa_privkey)) {
153          ERR_raise(ERR_LIB_DSA, DSA_R_BN_ERROR);
154          goto dsaerr;
155      }
156      /* Calculate public key */
157      if ((dsa_pubkey = BN_new()) == NULL) {
158          ERR_raise(ERR_LIB_DSA, ERR_R_MALLOC_FAILURE);
159          goto dsaerr;
160      }
161      if ((ctx = BN_CTX_new()) == NULL) {
162          ERR_raise(ERR_LIB_DSA, ERR_R_MALLOC_FAILURE);
163          goto dsaerr;
164      }
165  
166      dsa_p = DSA_get0_p(dsa);
167      dsa_g = DSA_get0_g(dsa);
168      BN_set_flags(dsa_privkey, BN_FLG_CONSTTIME);
169      if (!BN_mod_exp(dsa_pubkey, dsa_g, dsa_privkey, dsa_p, ctx)) {
170          ERR_raise(ERR_LIB_DSA, DSA_R_BN_ERROR);
171          goto dsaerr;
172      }
173      DSA_set0_key(dsa, dsa_pubkey, dsa_privkey);
174  
175      goto done;
176  
177   decerr:
178      ERR_raise(ERR_LIB_DSA, DSA_R_DECODE_ERROR);
179   dsaerr:
180      BN_free(dsa_privkey);
181      BN_free(dsa_pubkey);
182      DSA_free(dsa);
183      dsa = NULL;
184   done:
185      BN_CTX_free(ctx);
186      ASN1_STRING_clear_free(privkey);
187      return dsa;
188  }
189  #endif
190