/* $OpenBSD: dsa_pmeth.c,v 1.13 2021/12/04 16:08:32 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/err.h>

#include <openssl/evp.h>

#include <openssl/x509.h>

#include "bn_lcl.h"

#include "dsa_locl.h"

#include "evp_locl.h"

/* DSA pkey context structure */

typedef struct {

  /* Parameter gen parameters */

  int nbits;    /* size of p in bits (default: 1024) */

  int qbits;    /* size of q in bits (default: 160)  */

  const EVP_MD *pmd;  /* MD for parameter generation */

  /* Keygen callback info */

  int gentmp[2];

  /* message digest */

  const EVP_MD *md; /* MD for the signature */

} DSA_PKEY_CTX;

static int

pkey_dsa_init(EVP_PKEY_CTX *ctx)

{

  DSA_PKEY_CTX *dctx;

  dctx = malloc(sizeof(DSA_PKEY_CTX));

  if (!dctx)

    return 0;

  dctx->nbits = 1024;

  dctx->qbits = 160;

  dctx->pmd = NULL;

  dctx->md = NULL;

  ctx->data = dctx;

  ctx->keygen_info = dctx->gentmp;

  ctx->keygen_info_count = 2;

  return 1;

}

static int

pkey_dsa_copy(EVP_PKEY_CTX *dst, EVP_PKEY_CTX *src)

{

  DSA_PKEY_CTX *dctx, *sctx;

  if (!pkey_dsa_init(dst))

    return 0;

        sctx = src->data;

  dctx = dst->data;

  dctx->nbits = sctx->nbits;

  dctx->qbits = sctx->qbits;

  dctx->pmd = sctx->pmd;

  dctx->md  = sctx->md;

  return 1;

}

static void

pkey_dsa_cleanup(EVP_PKEY_CTX *ctx)

{

  DSA_PKEY_CTX *dctx = ctx->data;

  free(dctx);

}

static int

pkey_dsa_sign(EVP_PKEY_CTX *ctx, unsigned char *sig, size_t *siglen,

    const unsigned char *tbs, size_t tbslen)

{

  int ret, type;

  unsigned int sltmp;

  DSA_PKEY_CTX *dctx = ctx->data;

  DSA *dsa = ctx->pkey->pkey.dsa;

  if (dctx->md)

    type = EVP_MD_type(dctx->md);

  else

    type = NID_sha1;

  ret = DSA_sign(type, tbs, tbslen, sig, &sltmp, dsa);

  if (ret <= 0)

    return ret;

  *siglen = sltmp;

  return 1;

}

static int

pkey_dsa_verify(EVP_PKEY_CTX *ctx, const unsigned char *sig, size_t siglen,

    const unsigned char *tbs, size_t tbslen)

{

  int ret, type;

  DSA_PKEY_CTX *dctx = ctx->data;

  DSA *dsa = ctx->pkey->pkey.dsa;

  if (dctx->md)

    type = EVP_MD_type(dctx->md);

  else

    type = NID_sha1;

  ret = DSA_verify(type, tbs, tbslen, sig, siglen, dsa);

  return ret;

}

static int

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

{

  DSA_PKEY_CTX *dctx = ctx->data;

  switch (type) {

  case EVP_PKEY_CTRL_DSA_PARAMGEN_BITS:

    if (p1 < 256)

      return -2;

    dctx->nbits = p1;

    return 1;

  case EVP_PKEY_CTRL_DSA_PARAMGEN_Q_BITS:

    if (p1 != 160 && p1 != 224 && p1 && p1 != 256)

      return -2;

    dctx->qbits = p1;

    return 1;

  case EVP_PKEY_CTRL_DSA_PARAMGEN_MD:

    switch (EVP_MD_type((const EVP_MD *)p2)) {

    case NID_sha1:

    case NID_sha224:

    case NID_sha256:

      break;

    default:

      DSAerror(DSA_R_INVALID_DIGEST_TYPE);

      return 0;

    }

    dctx->md = p2;

    return 1;

  case EVP_PKEY_CTRL_MD:

    switch (EVP_MD_type((const EVP_MD *)p2)) {

    case NID_sha1:

    case NID_dsa:

    case NID_dsaWithSHA:

    case NID_sha224:

    case NID_sha256:

    case NID_sha384:

    case NID_sha512:

      break;

    default:

      DSAerror(DSA_R_INVALID_DIGEST_TYPE);

      return 0;

    }

    dctx->md = p2;

    return 1;

  case EVP_PKEY_CTRL_GET_MD:

    *(const EVP_MD **)p2 = dctx->md;

    return 1;

  case EVP_PKEY_CTRL_DIGESTINIT:

  case EVP_PKEY_CTRL_PKCS7_SIGN:

  case EVP_PKEY_CTRL_CMS_SIGN:

    return 1;

  case EVP_PKEY_CTRL_PEER_KEY:

    DSAerror(EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);

    return -2;  

  default:

    return -2;

  }

}

static int

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

{

  long lval;

  char *ep;

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

    int nbits;

    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;

    nbits = lval;

    return EVP_PKEY_CTX_set_dsa_paramgen_bits(ctx, nbits);

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

    int qbits;

    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;

    qbits = lval;

    return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_DSA,

        EVP_PKEY_OP_PARAMGEN, EVP_PKEY_CTRL_DSA_PARAMGEN_Q_BITS,

        qbits, NULL);

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

    return EVP_PKEY_CTX_ctrl(ctx, EVP_PKEY_DSA,

        EVP_PKEY_OP_PARAMGEN, EVP_PKEY_CTRL_DSA_PARAMGEN_MD, 0, 

        (void *)EVP_get_digestbyname(value));

  }

not_a_number:

out_of_range:

  return -2;

}

static int

pkey_dsa_paramgen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)

{

  DSA *dsa = NULL;

  DSA_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;

  dsa = DSA_new();

  if (!dsa)

    return 0;

  ret = dsa_builtin_paramgen(dsa, dctx->nbits, dctx->qbits, dctx->pmd,

      NULL, 0, NULL, NULL, NULL, pcb);

  if (ret)

    EVP_PKEY_assign_DSA(pkey, dsa);

  else

    DSA_free(dsa);

  return ret;

}

static int

pkey_dsa_keygen(EVP_PKEY_CTX *ctx, EVP_PKEY *pkey)

{

  DSA *dsa = NULL;

  if (ctx->pkey == NULL) {

    DSAerror(DSA_R_NO_PARAMETERS_SET);

    return 0;

  }

  dsa = DSA_new();

  if (!dsa)

    return 0;

  EVP_PKEY_assign_DSA(pkey, dsa);

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

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

    return 0;

  return DSA_generate_key(pkey->pkey.dsa);

}

const EVP_PKEY_METHOD dsa_pkey_meth = {

  .pkey_id = EVP_PKEY_DSA,

  .flags = EVP_PKEY_FLAG_AUTOARGLEN,

  .init = pkey_dsa_init,

  .copy = pkey_dsa_copy,

  .cleanup = pkey_dsa_cleanup,

  .paramgen = pkey_dsa_paramgen,

  .keygen = pkey_dsa_keygen,

  .sign = pkey_dsa_sign,

  .verify = pkey_dsa_verify,

  .ctrl = pkey_dsa_ctrl,

  .ctrl_str = pkey_dsa_ctrl_str

};