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 #include <stdio.h>
  11 #include "internal/cryptlib.h"
  12 #include <openssl/bn.h>
  13 #include "dh_local.h"
  14 #include <openssl/objects.h>
  15 #include <openssl/asn1t.h>
  16
  17 /* Override the default free and new methods */
  18 static int dh_cb(int operation, ASN1_VALUE **pval, const ASN1_ITEM *it,
  19                  void *exarg)
  20 {
  21     if (operation == ASN1_OP_NEW_PRE) {
  22         *pval = (ASN1_VALUE *)DH_new();
  23         if (*pval != NULL)
  24             return 2;
  25         return 0;
  26     } else if (operation == ASN1_OP_FREE_PRE) {
  27         DH_free((DH *)*pval);
  28         *pval = NULL;
  29         return 2;
  30     } else if (operation == ASN1_OP_D2I_POST) {
  31         ((DH *)*pval)->dirty_cnt++;
  32     }
  33     return 1;
  34 }
  35
  36 ASN1_SEQUENCE_cb(DHparams, dh_cb) = {
  37         ASN1_SIMPLE(DH, params.p, BIGNUM),
  38         ASN1_SIMPLE(DH, params.g, BIGNUM),
  39         ASN1_OPT_EMBED(DH, length, ZINT32),
  40 } ASN1_SEQUENCE_END_cb(DH, DHparams)
  41
  42 IMPLEMENT_ASN1_ENCODE_FUNCTIONS_fname(DH, DHparams, DHparams)
  43
  44 /*
  45  * Internal only structures for handling X9.42 DH: this gets translated to or
  46  * from a DH structure straight away.
  47  */
  48
  49 typedef struct {
  50     ASN1_BIT_STRING *seed;
  51     BIGNUM *counter;
  52 } int_dhvparams;
  53
  54 typedef struct {
  55     BIGNUM *p;
  56     BIGNUM *q;
  57     BIGNUM *g;
  58     BIGNUM *j;
  59     int_dhvparams *vparams;
  60 } int_dhx942_dh;
  61
  62 ASN1_SEQUENCE(DHvparams) = {
  63         ASN1_SIMPLE(int_dhvparams, seed, ASN1_BIT_STRING),
  64         ASN1_SIMPLE(int_dhvparams, counter, BIGNUM)
  65 } static_ASN1_SEQUENCE_END_name(int_dhvparams, DHvparams)
  66
  67 ASN1_SEQUENCE(DHxparams) = {
  68         ASN1_SIMPLE(int_dhx942_dh, p, BIGNUM),
  69         ASN1_SIMPLE(int_dhx942_dh, g, BIGNUM),
  70         ASN1_SIMPLE(int_dhx942_dh, q, BIGNUM),
  71         ASN1_OPT(int_dhx942_dh, j, BIGNUM),
  72         ASN1_OPT(int_dhx942_dh, vparams, DHvparams),
  73 } static_ASN1_SEQUENCE_END_name(int_dhx942_dh, DHxparams)
  74
  75 int_dhx942_dh *d2i_int_dhx(int_dhx942_dh **a,
  76                            const unsigned char **pp, long length);
  77 int i2d_int_dhx(const int_dhx942_dh *a, unsigned char **pp);
  78
  79 IMPLEMENT_ASN1_ENCODE_FUNCTIONS_fname(int_dhx942_dh, DHxparams, int_dhx)
  80
  81 /* Application public function: read in X9.42 DH parameters into DH structure */
  82
  83 DH *d2i_DHxparams(DH **a, const unsigned char **pp, long length)
  84 {
  85     FFC_PARAMS *params;
  86     int_dhx942_dh *dhx = NULL;
  87     DH *dh = NULL;
  88
  89     dh = DH_new();
  90     if (dh == NULL)
  91         return NULL;
  92     dhx = d2i_int_dhx(NULL, pp, length);
  93     if (dhx == NULL) {
  94         DH_free(dh);
  95         return NULL;
  96     }
  97
  98     if (a != NULL) {
  99         DH_free(*a);
 100         *a = dh;
 101     }
 102
 103     params = &dh->params;
 104     DH_set0_pqg(dh, dhx->p, dhx->q, dhx->g);
 105     ffc_params_set0_j(params, dhx->j);
 106
 107     if (dhx->vparams != NULL) {
 108         /* The counter has a maximum value of 4 * numbits(p) - 1 */
 109         size_t counter = (size_t)BN_get_word(dhx->vparams->counter);
 110         ffc_params_set_validate_params(params, dhx->vparams->seed->data,
 111                                        dhx->vparams->seed->length, counter);
 112         ASN1_BIT_STRING_free(dhx->vparams->seed);
 113         BN_free(dhx->vparams->counter);
 114         OPENSSL_free(dhx->vparams);
 115         dhx->vparams = NULL;
 116     }
 117
 118     OPENSSL_free(dhx);
 119     return dh;
 120 }
 121
 122 int i2d_DHxparams(const DH *dh, unsigned char **pp)
 123 {
 124     int ret = 0;
 125     int_dhx942_dh dhx;
 126     int_dhvparams dhv = { NULL, NULL };
 127     ASN1_BIT_STRING seed;
 128     size_t seedlen = 0;
 129     const FFC_PARAMS *params = &dh->params;
 130     int counter;
 131
 132     ffc_params_get0_pqg(params, (const BIGNUM **)&dhx.p,
 133                         (const BIGNUM **)&dhx.q, (const BIGNUM **)&dhx.g);
 134     dhx.j = params->j;
 135     ffc_params_get_validate_params(params, &seed.data, &seedlen, &counter);
 136     seed.length = (int)seedlen;
 137
 138     if (counter != -1 && seed.data != NULL && seed.length > 0) {
 139         seed.flags = ASN1_STRING_FLAG_BITS_LEFT;
 140         dhv.seed = &seed;
 141         dhv.counter = BN_new();
 142         if (dhv.counter == NULL)
 143             return 0;
 144         if (!BN_set_word(dhv.counter, (BN_ULONG)counter))
 145             goto err;
 146         dhx.vparams = &dhv;
 147     } else {
 148         dhx.vparams = NULL;
 149     }
 150     ret = i2d_int_dhx(&dhx, pp);
 151 err:
 152     BN_free(dhv.counter);
 153     return ret;
 154 }