/* $OpenBSD: dh_pmeth.c,v 1.12 2022/01/07 09:27:13 tb Exp $ */

/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL

 * project 2006.

 */

/* ====================================================================

 * Copyright (c) 2006 The OpenSSL Project.  All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer. 

 *

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in

 *    the documentation and/or other materials provided with the

 *    distribution.

 *

 * 3. All advertising materials mentioning features or use of this

 *    software must display the following acknowledgment:

 *    "This product includes software developed by the OpenSSL Project

 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"

 *

 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to

 *    endorse or promote products derived from this software without

 *    prior written permission. For written permission, please contact

 *    licensing@OpenSSL.org.

 *

 * 5. Products derived from this software may not be called "OpenSSL"

 *    nor may "OpenSSL" appear in their names without prior written

 *    permission of the OpenSSL Project.

 *

 * 6. Redistributions of any form whatsoever must retain the following

 *    acknowledgment:

 *    "This product includes software developed by the OpenSSL Project

 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"

 *

 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY

 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR

 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;

 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,

 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)

 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED

 * OF THE POSSIBILITY OF SUCH DAMAGE.

 * ====================================================================

 *

 * This product includes cryptographic software written by Eric Young

 * (eay@cryptsoft.com).  This product includes software written by Tim

 * Hudson (tjh@cryptsoft.com).

 *

 */

#include <limits.h>

#include <stdio.h>

#include <string.h>

#include <openssl/asn1t.h>

#include <openssl/bn.h>

#include <openssl/dh.h>

#include <openssl/err.h>

#include <openssl/evp.h>

#include <openssl/x509.h>

#include "bn_lcl.h"

#include "dh_local.h"

#include "evp_locl.h"

/* DH pkey context structure */

typedef struct {

  /* Parameter gen parameters */

  int prime_len;

  int generator;

  int use_dsa;

  /* Keygen callback info */

  int gentmp[2];

  /* message digest */

} DH_PKEY_CTX;

static int

pkey_dh_init(EVP_PKEY_CTX *ctx)

{

  DH_PKEY_CTX *dctx;

  dctx = malloc(sizeof(DH_PKEY_CTX));

  if (!dctx)

    return 0;

  dctx->prime_len = 1024;

  dctx->generator = 2;

  dctx->use_dsa = 0;

  ctx->data = dctx;

  ctx->keygen_info = dctx->gentmp;

  ctx->keygen_info_count = 2;

  return 1;

}

static int

pkey_dh_copy(EVP_PKEY_CTX *dst, EVP_PKEY_CTX *src)

{

  DH_PKEY_CTX *dctx, *sctx;

  if (!pkey_dh_init(dst))

    return 0;

        sctx = src->data;

  dctx = dst->data;

  dctx->prime_len = sctx->prime_len;

  dctx->generator = sctx->generator;

  dctx->use_dsa = sctx->use_dsa;

  return 1;

}

static void

pkey_dh_cleanup(EVP_PKEY_CTX *ctx)

{

  DH_PKEY_CTX *dctx = ctx->data;

  free(dctx);

}

static int

pkey_dh_ctrl(EVP_PKEY_CTX *ctx, int type, int p1, void *p2)

{

  DH_PKEY_CTX *dctx = ctx->data;

  switch (type) {

  case EVP_PKEY_CTRL_DH_PARAMGEN_PRIME_LEN:

    if (p1 < 256)

      return -2;

    dctx->prime_len = p1;

    return 1;

  case EVP_PKEY_CTRL_DH_PARAMGEN_GENERATOR:

    dctx->generator = p1;

    return 1;

  case EVP_PKEY_CTRL_PEER_KEY:

    /* Default behaviour is OK */

    return 1;

  default:

    return -2;

  }

}

static int

pkey_dh_ctrl_str(EVP_PKEY_CTX *ctx, const char *type, const char *value)

{

  long lval;

  char *ep;

  int len;

  if (!strcmp(type, "dh_paramgen_prime_len")) {

    errno = 0;

    lval = strtol(value, &ep, 10);

    if (value[0] == '\0' || *ep != '\0')

      goto not_a_number;

    if ((errno == ERANGE &&

        (lval == LONG_MAX || lval == LONG_MIN)) ||

        (lval > INT_MAX || lval < INT_MIN))

      goto out_of_range;

    len = lval;

    return EVP_PKEY_CTX_set_dh_paramgen_prime_len(ctx, len);

  } else if (!strcmp(type, "dh_paramgen_generator")) {

    errno = 0;

    lval = strtol(value, &ep, 10);

    if (value[0] == '\0' || *ep != '\0')

      goto not_a_number;

    if ((errno == ERANGE &&

        (lval == LONG_MAX || lval == LONG_MIN)) ||

        (lval > INT_MAX || lval < INT_MIN))

      goto out_of_range;

    len = lval;

    return EVP_PKEY_CTX_set_dh_paramgen_generator(ctx, len);

  }

not_a_number:

out_of_range:

  return -2;

}

static int

pkey_dh_paramgen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)

{

  DH *dh = NULL;

  DH_PKEY_CTX *dctx = ctx->data;

  BN_GENCB *pcb, cb;

  int ret;

  if (ctx->pkey_gencb) {

    pcb = &cb;

    evp_pkey_set_cb_translate(pcb, ctx);

  } else

    pcb = NULL;

  dh = DH_new();

  if (!dh)

    return 0;

  ret = DH_generate_parameters_ex(dh, dctx->prime_len, dctx->generator,

      pcb);

  if (ret)

    EVP_PKEY_assign_DH(pkey, dh);

  else

    DH_free(dh);

  return ret;

}

static int

pkey_dh_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)

{

  DH *dh = NULL;

  if (ctx->pkey == NULL) {

    DHerror(DH_R_NO_PARAMETERS_SET);

    return 0;

  }

  dh = DH_new();

  if (!dh)

    return 0;

  EVP_PKEY_assign_DH(pkey, dh);

  /* Note: if error return, pkey is freed by parent routine */

  if (!EVP_PKEY_copy_parameters(pkey, ctx->pkey))

    return 0;

  return DH_generate_key(pkey->pkey.dh);

}

static int

pkey_dh_derive(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *keylen)

{

  int ret;

  if (!ctx->pkey || !ctx->peerkey) {

    DHerror(DH_R_KEYS_NOT_SET);

    return 0;

  }

  ret = DH_compute_key(key, ctx->peerkey->pkey.dh->pub_key,

      ctx->pkey->pkey.dh);

  if (ret < 0)

    return ret;

  *keylen = ret;

  return 1;

}

const EVP_PKEY_METHOD dh_pkey_meth = {

  .pkey_id = EVP_PKEY_DH,

  .flags = EVP_PKEY_FLAG_AUTOARGLEN,

  .init = pkey_dh_init,

  .copy = pkey_dh_copy,

  .cleanup = pkey_dh_cleanup,

  .paramgen = pkey_dh_paramgen,

  .keygen = pkey_dh_keygen,

  .derive = pkey_dh_derive,

  .ctrl = pkey_dh_ctrl,

  .ctrl_str = pkey_dh_ctrl_str

};