crypto/dh/dh_asn1.c

   1 /*
   2  * Copyright 2000-2020 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  * 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 <stdio.h>
  17 #include "internal/cryptlib.h"
  18 #include <openssl/bn.h>
  19 #include "dh_local.h"
  20 #include <openssl/objects.h>
  21 #include <openssl/asn1t.h>
  22
  23 /* Override the default free and new methods */
  24 static int dh_cb(int operation, ASN1_VALUE **pval, const ASN1_ITEM *it,
  25                  void *exarg)
  26 {
  27     if (operation == ASN1_OP_NEW_PRE) {
  28         *pval = (ASN1_VALUE *)DH_new();
  29         if (*pval != NULL)
  30             return 2;
  31         return 0;
  32     } else if (operation == ASN1_OP_FREE_PRE) {
  33         DH_free((DH *)*pval);
  34         *pval = NULL;
  35         return 2;
  36     } else if (operation == ASN1_OP_D2I_POST) {
  37         DH *dh = (DH *)*pval;
  38
  39         DH_clear_flags(dh, DH_FLAG_TYPE_MASK);
  40         DH_set_flags(dh, DH_FLAG_TYPE_DH);
  41         dh->dirty_cnt++;
  42     }
  43     return 1;
  44 }
  45
  46 ASN1_SEQUENCE_cb(DHparams, dh_cb) = {
  47         ASN1_SIMPLE(DH, params.p, BIGNUM),
  48         ASN1_SIMPLE(DH, params.g, BIGNUM),
  49         ASN1_OPT_EMBED(DH, length, ZINT32),
  50 } ASN1_SEQUENCE_END_cb(DH, DHparams)
  51
  52 IMPLEMENT_ASN1_ENCODE_FUNCTIONS_fname(DH, DHparams, DHparams)
  53
  54 /*
  55  * Internal only structures for handling X9.42 DH: this gets translated to or
  56  * from a DH structure straight away.
  57  */
  58
  59 typedef struct {
  60     ASN1_BIT_STRING *seed;
  61     BIGNUM *counter;
  62 } int_dhvparams;
  63
  64 typedef struct {
  65     BIGNUM *p;
  66     BIGNUM *q;
  67     BIGNUM *g;
  68     BIGNUM *j;
  69     int_dhvparams *vparams;
  70 } int_dhx942_dh;
  71
  72 ASN1_SEQUENCE(DHvparams) = {
  73         ASN1_SIMPLE(int_dhvparams, seed, ASN1_BIT_STRING),
  74         ASN1_SIMPLE(int_dhvparams, counter, BIGNUM)
  75 } static_ASN1_SEQUENCE_END_name(int_dhvparams, DHvparams)
  76
  77 ASN1_SEQUENCE(DHxparams) = {
  78         ASN1_SIMPLE(int_dhx942_dh, p, BIGNUM),
  79         ASN1_SIMPLE(int_dhx942_dh, g, BIGNUM),
  80         ASN1_SIMPLE(int_dhx942_dh, q, BIGNUM),
  81         ASN1_OPT(int_dhx942_dh, j, BIGNUM),
  82         ASN1_OPT(int_dhx942_dh, vparams, DHvparams),
  83 } static_ASN1_SEQUENCE_END_name(int_dhx942_dh, DHxparams)
  84
  85 int_dhx942_dh *d2i_int_dhx(int_dhx942_dh **a,
  86                            const unsigned char **pp, long length);
  87 int i2d_int_dhx(const int_dhx942_dh *a, unsigned char **pp);
  88
  89 IMPLEMENT_ASN1_ENCODE_FUNCTIONS_fname(int_dhx942_dh, DHxparams, int_dhx)
  90
  91 /* Application public function: read in X9.42 DH parameters into DH structure */
  92
  93 DH *d2i_DHxparams(DH **a, const unsigned char **pp, long length)
  94 {
  95     FFC_PARAMS *params;
  96     int_dhx942_dh *dhx = NULL;
  97     DH *dh = NULL;
  98
  99     dh = DH_new();
 100     if (dh == NULL)
 101         return NULL;
 102     dhx = d2i_int_dhx(NULL, pp, length);
 103     if (dhx == NULL) {
 104         DH_free(dh);
 105         return NULL;
 106     }
 107
 108     if (a != NULL) {
 109         DH_free(*a);
 110         *a = dh;
 111     }
 112
 113     params = &dh->params;
 114     DH_set0_pqg(dh, dhx->p, dhx->q, dhx->g);
 115     ossl_ffc_params_set0_j(params, dhx->j);
 116
 117     if (dhx->vparams != NULL) {
 118         /* The counter has a maximum value of 4 * numbits(p) - 1 */
 119         size_t counter = (size_t)BN_get_word(dhx->vparams->counter);
 120         ossl_ffc_params_set_validate_params(params, dhx->vparams->seed->data,
 121                                             dhx->vparams->seed->length,
 122                                             counter);
 123         ASN1_BIT_STRING_free(dhx->vparams->seed);
 124         BN_free(dhx->vparams->counter);
 125         OPENSSL_free(dhx->vparams);
 126         dhx->vparams = NULL;
 127     }
 128
 129     OPENSSL_free(dhx);
 130     DH_clear_flags(dh, DH_FLAG_TYPE_MASK);
 131     DH_set_flags(dh, DH_FLAG_TYPE_DHX);
 132     return dh;
 133 }
 134
 135 int i2d_DHxparams(const DH *dh, unsigned char **pp)
 136 {
 137     int ret = 0;
 138     int_dhx942_dh dhx;
 139     int_dhvparams dhv = { NULL, NULL };
 140     ASN1_BIT_STRING seed;
 141     size_t seedlen = 0;
 142     const FFC_PARAMS *params = &dh->params;
 143     int counter;
 144
 145     ossl_ffc_params_get0_pqg(params, (const BIGNUM **)&dhx.p,
 146                              (const BIGNUM **)&dhx.q, (const BIGNUM **)&dhx.g);
 147     dhx.j = params->j;
 148     ossl_ffc_params_get_validate_params(params, &seed.data, &seedlen, &counter);
 149     seed.length = (int)seedlen;
 150
 151     if (counter != -1 && seed.data != NULL && seed.length > 0) {
 152         seed.flags = ASN1_STRING_FLAG_BITS_LEFT;
 153         dhv.seed = &seed;
 154         dhv.counter = BN_new();
 155         if (dhv.counter == NULL)
 156             return 0;
 157         if (!BN_set_word(dhv.counter, (BN_ULONG)counter))
 158             goto err;
 159         dhx.vparams = &dhv;
 160     } else {
 161         dhx.vparams = NULL;
 162     }
 163     ret = i2d_int_dhx(&dhx, pp);
 164 err:
 165     BN_free(dhv.counter);
 166     return ret;
 167 }