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_locl.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     }
  31     return 1;
  32 }
  33
  34 ASN1_SEQUENCE_cb(DHparams, dh_cb) = {
  35         ASN1_SIMPLE(DH, p, BIGNUM),
  36         ASN1_SIMPLE(DH, g, BIGNUM),
  37         ASN1_OPT_EMBED(DH, length, ZINT32),
  38 } ASN1_SEQUENCE_END_cb(DH, DHparams)
  39
  40 IMPLEMENT_ASN1_ENCODE_FUNCTIONS_const_fname(DH, DHparams, DHparams)
  41
  42 /*
  43  * Internal only structures for handling X9.42 DH: this gets translated to or
  44  * from a DH structure straight away.
  45  */
  46
  47 typedef struct {
  48     ASN1_BIT_STRING *seed;
  49     BIGNUM *counter;
  50 } int_dhvparams;
  51
  52 typedef struct {
  53     BIGNUM *p;
  54     BIGNUM *q;
  55     BIGNUM *g;
  56     BIGNUM *j;
  57     int_dhvparams *vparams;
  58 } int_dhx942_dh;
  59
  60 ASN1_SEQUENCE(DHvparams) = {
  61         ASN1_SIMPLE(int_dhvparams, seed, ASN1_BIT_STRING),
  62         ASN1_SIMPLE(int_dhvparams, counter, BIGNUM)
  63 } static_ASN1_SEQUENCE_END_name(int_dhvparams, DHvparams)
  64
  65 ASN1_SEQUENCE(DHxparams) = {
  66         ASN1_SIMPLE(int_dhx942_dh, p, BIGNUM),
  67         ASN1_SIMPLE(int_dhx942_dh, g, BIGNUM),
  68         ASN1_SIMPLE(int_dhx942_dh, q, BIGNUM),
  69         ASN1_OPT(int_dhx942_dh, j, BIGNUM),
  70         ASN1_OPT(int_dhx942_dh, vparams, DHvparams),
  71 } static_ASN1_SEQUENCE_END_name(int_dhx942_dh, DHxparams)
  72
  73 int_dhx942_dh *d2i_int_dhx(int_dhx942_dh **a,
  74                            const unsigned char **pp, long length);
  75 int i2d_int_dhx(const int_dhx942_dh *a, unsigned char **pp);
  76
  77 IMPLEMENT_ASN1_ENCODE_FUNCTIONS_const_fname(int_dhx942_dh, DHxparams, int_dhx)
  78
  79 /* Application public function: read in X9.42 DH parameters into DH structure */
  80
  81 DH *d2i_DHxparams(DH **a, const unsigned char **pp, long length)
  82 {
  83     int_dhx942_dh *dhx = NULL;
  84     DH *dh = NULL;
  85     dh = DH_new();
  86     if (dh == NULL)
  87         return NULL;
  88     dhx = d2i_int_dhx(NULL, pp, length);
  89     if (dhx == NULL) {
  90         DH_free(dh);
  91         return NULL;
  92     }
  93
  94     if (a) {
  95         DH_free(*a);
  96         *a = dh;
  97     }
  98
  99     dh->p = dhx->p;
 100     dh->q = dhx->q;
 101     dh->g = dhx->g;
 102     dh->j = dhx->j;
 103
 104     if (dhx->vparams) {
 105         dh->seed = dhx->vparams->seed->data;
 106         dh->seedlen = dhx->vparams->seed->length;
 107         dh->counter = dhx->vparams->counter;
 108         dhx->vparams->seed->data = NULL;
 109         ASN1_BIT_STRING_free(dhx->vparams->seed);
 110         OPENSSL_free(dhx->vparams);
 111         dhx->vparams = NULL;
 112     }
 113
 114     OPENSSL_free(dhx);
 115     return dh;
 116 }
 117
 118 int i2d_DHxparams(const DH *dh, unsigned char **pp)
 119 {
 120     int_dhx942_dh dhx;
 121     int_dhvparams dhv;
 122     ASN1_BIT_STRING bs;
 123     dhx.p = dh->p;
 124     dhx.g = dh->g;
 125     dhx.q = dh->q;
 126     dhx.j = dh->j;
 127     if (dh->counter && dh->seed && dh->seedlen > 0) {
 128         bs.flags = ASN1_STRING_FLAG_BITS_LEFT;
 129         bs.data = dh->seed;
 130         bs.length = dh->seedlen;
 131         dhv.seed = &bs;
 132         dhv.counter = dh->counter;
 133         dhx.vparams = &dhv;
 134     } else
 135         dhx.vparams = NULL;
 136
 137     return i2d_int_dhx(&dhx, pp);
 138 }