crypto/dh/dh_asn1.c

   1 /*
   2  * Copyright 2000-2016 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 *)*pval)->dirty_cnt++;
  38     }
  39     return 1;
  40 }
  41
  42 ASN1_SEQUENCE_cb(DHparams, dh_cb) = {
  43         ASN1_SIMPLE(DH, params.p, BIGNUM),
  44         ASN1_SIMPLE(DH, params.g, BIGNUM),
  45         ASN1_OPT_EMBED(DH, length, ZINT32),
  46 } ASN1_SEQUENCE_END_cb(DH, DHparams)
  47
  48 IMPLEMENT_ASN1_ENCODE_FUNCTIONS_fname(DH, DHparams, DHparams)
  49
  50 /*
  51  * Internal only structures for handling X9.42 DH: this gets translated to or
  52  * from a DH structure straight away.
  53  */
  54
  55 typedef struct {
  56     ASN1_BIT_STRING *seed;
  57     BIGNUM *counter;
  58 } int_dhvparams;
  59
  60 typedef struct {
  61     BIGNUM *p;
  62     BIGNUM *q;
  63     BIGNUM *g;
  64     BIGNUM *j;
  65     int_dhvparams *vparams;
  66 } int_dhx942_dh;
  67
  68 ASN1_SEQUENCE(DHvparams) = {
  69         ASN1_SIMPLE(int_dhvparams, seed, ASN1_BIT_STRING),
  70         ASN1_SIMPLE(int_dhvparams, counter, BIGNUM)
  71 } static_ASN1_SEQUENCE_END_name(int_dhvparams, DHvparams)
  72
  73 ASN1_SEQUENCE(DHxparams) = {
  74         ASN1_SIMPLE(int_dhx942_dh, p, BIGNUM),
  75         ASN1_SIMPLE(int_dhx942_dh, g, BIGNUM),
  76         ASN1_SIMPLE(int_dhx942_dh, q, BIGNUM),
  77         ASN1_OPT(int_dhx942_dh, j, BIGNUM),
  78         ASN1_OPT(int_dhx942_dh, vparams, DHvparams),
  79 } static_ASN1_SEQUENCE_END_name(int_dhx942_dh, DHxparams)
  80
  81 int_dhx942_dh *d2i_int_dhx(int_dhx942_dh **a,
  82                            const unsigned char **pp, long length);
  83 int i2d_int_dhx(const int_dhx942_dh *a, unsigned char **pp);
  84
  85 IMPLEMENT_ASN1_ENCODE_FUNCTIONS_fname(int_dhx942_dh, DHxparams, int_dhx)
  86
  87 /* Application public function: read in X9.42 DH parameters into DH structure */
  88
  89 DH *d2i_DHxparams(DH **a, const unsigned char **pp, long length)
  90 {
  91     FFC_PARAMS *params;
  92     int_dhx942_dh *dhx = NULL;
  93     DH *dh = NULL;
  94
  95     dh = DH_new();
  96     if (dh == NULL)
  97         return NULL;
  98     dhx = d2i_int_dhx(NULL, pp, length);
  99     if (dhx == NULL) {
 100         DH_free(dh);
 101         return NULL;
 102     }
 103
 104     if (a != NULL) {
 105         DH_free(*a);
 106         *a = dh;
 107     }
 108
 109     params = &dh->params;
 110     DH_set0_pqg(dh, dhx->p, dhx->q, dhx->g);
 111     ffc_params_set0_j(params, dhx->j);
 112
 113     if (dhx->vparams != NULL) {
 114         /* The counter has a maximum value of 4 * numbits(p) - 1 */
 115         size_t counter = (size_t)BN_get_word(dhx->vparams->counter);
 116         ffc_params_set_validate_params(params, dhx->vparams->seed->data,
 117                                        dhx->vparams->seed->length, counter);
 118         ASN1_BIT_STRING_free(dhx->vparams->seed);
 119         BN_free(dhx->vparams->counter);
 120         OPENSSL_free(dhx->vparams);
 121         dhx->vparams = NULL;
 122     }
 123
 124     OPENSSL_free(dhx);
 125     return dh;
 126 }
 127
 128 int i2d_DHxparams(const DH *dh, unsigned char **pp)
 129 {
 130     int ret = 0;
 131     int_dhx942_dh dhx;
 132     int_dhvparams dhv = { NULL, NULL };
 133     ASN1_BIT_STRING seed;
 134     size_t seedlen = 0;
 135     const FFC_PARAMS *params = &dh->params;
 136     int counter;
 137
 138     ffc_params_get0_pqg(params, (const BIGNUM **)&dhx.p,
 139                         (const BIGNUM **)&dhx.q, (const BIGNUM **)&dhx.g);
 140     dhx.j = params->j;
 141     ffc_params_get_validate_params(params, &seed.data, &seedlen, &counter);
 142     seed.length = (int)seedlen;
 143
 144     if (counter != -1 && seed.data != NULL && seed.length > 0) {
 145         seed.flags = ASN1_STRING_FLAG_BITS_LEFT;
 146         dhv.seed = &seed;
 147         dhv.counter = BN_new();
 148         if (dhv.counter == NULL)
 149             return 0;
 150         if (!BN_set_word(dhv.counter, (BN_ULONG)counter))
 151             goto err;
 152         dhx.vparams = &dhv;
 153     } else {
 154         dhx.vparams = NULL;
 155     }
 156     ret = i2d_int_dhx(&dhx, pp);
 157 err:
 158     BN_free(dhv.counter);
 159     return ret;
 160 }