crypto/dsa/dsa_key.c

   1 /*
   2  * Copyright 1995-2020 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 "crypto/dsa.h"
  22 #include "dsa_local.h"
  23
  24 static int dsa_keygen(DSA *dsa, int pairwise_test);
  25 static int dsa_keygen_pairwise_test(DSA *dsa, OSSL_CALLBACK *cb, void *cbarg);
  26
  27 int DSA_generate_key(DSA *dsa)
  28 {
  29 #ifndef FIPS_MODE
  30     if (dsa->meth->dsa_keygen != NULL)
  31         return dsa->meth->dsa_keygen(dsa);
  32 #endif
  33     return dsa_keygen(dsa, 0);
  34 }
  35
  36 int dsa_generate_public_key(BN_CTX *ctx, const DSA *dsa, const BIGNUM *priv_key,
  37                             BIGNUM *pub_key)
  38 {
  39     int ret = 0;
  40     BIGNUM *prk = BN_new();
  41
  42     if (prk == NULL)
  43         return 0;
  44     BN_with_flags(prk, priv_key, BN_FLG_CONSTTIME);
  45
  46     /* pub_key = g ^ priv_key mod p */
  47     if (!BN_mod_exp(pub_key, dsa->params.g, prk, dsa->params.p, ctx))
  48         goto err;
  49     ret = 1;
  50 err:
  51     BN_clear_free(prk);
  52     return ret;
  53 }
  54
  55 static int dsa_keygen(DSA *dsa, int pairwise_test)
  56 {
  57     int ok = 0;
  58     BN_CTX *ctx = NULL;
  59     BIGNUM *pub_key = NULL, *priv_key = NULL;
  60
  61     if ((ctx = BN_CTX_new_ex(dsa->libctx)) == NULL)
  62         goto err;
  63
  64     if (dsa->priv_key == NULL) {
  65         if ((priv_key = BN_secure_new()) == NULL)
  66             goto err;
  67     } else {
  68         priv_key = dsa->priv_key;
  69     }
  70
  71     if (!ffc_generate_private_key(ctx, &dsa->params, BN_num_bits(dsa->params.q),
  72                                   112, priv_key))
  73         goto err;
  74
  75     if (dsa->pub_key == NULL) {
  76         if ((pub_key = BN_new()) == NULL)
  77             goto err;
  78     } else {
  79         pub_key = dsa->pub_key;
  80     }
  81
  82     if (!dsa_generate_public_key(ctx, dsa, priv_key, pub_key))
  83         goto err;
  84
  85     dsa->priv_key = priv_key;
  86     dsa->pub_key = pub_key;
  87
  88 #ifdef FIPS_MODE
  89     pairwise_test = 1;
  90 #endif /* FIPS_MODE */
  91
  92     ok = 1;
  93     if (pairwise_test) {
  94         OSSL_CALLBACK *cb = NULL;
  95         void *cbarg = NULL;
  96
  97         OSSL_SELF_TEST_get_callback(dsa->libctx, &cb, &cbarg);
  98         ok = dsa_keygen_pairwise_test(dsa, cb, cbarg);
  99         if (!ok) {
 100             BN_free(dsa->pub_key);
 101             BN_clear_free(dsa->priv_key);
 102             BN_CTX_free(ctx);
 103             return ok;
 104         }
 105     }
 106     dsa->dirty_cnt++;
 107
 108  err:
 109     if (pub_key != dsa->pub_key)
 110         BN_free(pub_key);
 111     if (priv_key != dsa->priv_key)
 112         BN_free(priv_key);
 113     BN_CTX_free(ctx);
 114
 115     return ok;
 116 }
 117
 118 /*
 119  * FIPS 140-2 IG 9.9 AS09.33
 120  * Perform a sign/verify operation.
 121  */
 122 static int dsa_keygen_pairwise_test(DSA *dsa, OSSL_CALLBACK *cb, void *cbarg)
 123 {
 124     int ret = 0;
 125     unsigned char dgst[16] = {0};
 126     unsigned int dgst_len = (unsigned int)sizeof(dgst);
 127     DSA_SIG *sig = NULL;
 128     OSSL_SELF_TEST *st = NULL;
 129
 130     st = OSSL_SELF_TEST_new(cb, cbarg);
 131     if (st == NULL)
 132         goto err;
 133
 134     OSSL_SELF_TEST_onbegin(st, OSSL_SELF_TEST_TYPE_PCT,
 135                            OSSL_SELF_TEST_DESC_PCT_DSA);
 136
 137     sig = DSA_do_sign(dgst, (int)dgst_len, dsa);
 138     if (sig == NULL)
 139         goto err;
 140
 141     OSSL_SELF_TEST_oncorrupt_byte(st, dgst);
 142
 143     if (DSA_do_verify(dgst, dgst_len, sig, dsa) != 1)
 144         goto err;
 145
 146     ret = 1;
 147 err:
 148     OSSL_SELF_TEST_onend(st, ret);
 149     OSSL_SELF_TEST_free(st);
 150     DSA_SIG_free(sig);
 151     return ret;
 152 }