/* $OpenBSD: dsa_ameth.c,v 1.37 2022/06/27 12:36:05 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 <stdio.h>

#include <openssl/opensslconf.h>

#include <openssl/asn1.h>

#include <openssl/bn.h>

#include <openssl/cms.h>

#include <openssl/dsa.h>

#include <openssl/err.h>

#include <openssl/x509.h>

#include "asn1_locl.h"

#include "bn_lcl.h"

#include "dsa_locl.h"

#include "evp_locl.h"

static int

dsa_pub_decode(EVP_PKEY *pkey, X509_PUBKEY *pubkey)

{

  const unsigned char *p, *pm;

  int pklen, pmlen;

  int ptype;

  const void *pval;

  const ASN1_STRING *pstr;

  X509_ALGOR *palg;

  ASN1_INTEGER *public_key = NULL;

  DSA *dsa = NULL;

  if (!X509_PUBKEY_get0_param(NULL, &p, &pklen, &palg, pubkey))

    return 0;

  X509_ALGOR_get0(NULL, &ptype, &pval, palg);

  if (ptype == V_ASN1_SEQUENCE) {

    pstr = pval;

    pm = pstr->data;

    pmlen = pstr->length;

    if (!(dsa = d2i_DSAparams(NULL, &pm, pmlen))) {

      DSAerror(DSA_R_DECODE_ERROR);

      goto err;

    }

  } else if (ptype == V_ASN1_NULL || ptype == V_ASN1_UNDEF) {

    if (!(dsa = DSA_new())) {

      DSAerror(ERR_R_MALLOC_FAILURE);

      goto err;

    }

  } else {

    DSAerror(DSA_R_PARAMETER_ENCODING_ERROR);

    goto err;

  }

  if (!(public_key = d2i_ASN1_INTEGER(NULL, &p, pklen))) {

    DSAerror(DSA_R_DECODE_ERROR);

    goto err;

  }

  if (!(dsa->pub_key = ASN1_INTEGER_to_BN(public_key, NULL))) {

    DSAerror(DSA_R_BN_DECODE_ERROR);

    goto err;

  }

  ASN1_INTEGER_free(public_key);

  EVP_PKEY_assign_DSA(pkey, dsa);

  return 1;

err:

  if (public_key)

    ASN1_INTEGER_free(public_key);

  DSA_free(dsa);

  return 0;

}

static int

dsa_pub_encode(X509_PUBKEY *pk, const EVP_PKEY *pkey)

{

  DSA *dsa;

  ASN1_INTEGER *pubint = NULL;

  ASN1_STRING *str = NULL;

  int ptype = V_ASN1_UNDEF;

  unsigned char *penc = NULL;

  int penclen;

  dsa = pkey->pkey.dsa;

  if (pkey->save_parameters && dsa->p && dsa->q && dsa->g) {

    if ((str = ASN1_STRING_new()) == NULL) {

      DSAerror(ERR_R_MALLOC_FAILURE);

      goto err;

    }

    str->length = i2d_DSAparams(dsa, &str->data);

    if (str->length <= 0) {

      DSAerror(ERR_R_MALLOC_FAILURE);

      goto err;

    }

    ptype = V_ASN1_SEQUENCE;

  }

  if ((pubint = BN_to_ASN1_INTEGER(dsa->pub_key, NULL)) == NULL) {

    DSAerror(ERR_R_MALLOC_FAILURE);

    goto err;

  }

  penclen = i2d_ASN1_INTEGER(pubint, &penc);

  ASN1_INTEGER_free(pubint);

  if (penclen <= 0) {

    DSAerror(ERR_R_MALLOC_FAILURE);

    goto err;

  }

  if (X509_PUBKEY_set0_param(pk, OBJ_nid2obj(EVP_PKEY_DSA), ptype, str,

      penc, penclen))

    return 1;

 err:

  free(penc);

  ASN1_STRING_free(str);

  return 0;

}

/* In PKCS#8 DSA: you just get a private key integer and parameters in the

 * AlgorithmIdentifier the pubkey must be recalculated.

 */

static int

dsa_priv_decode(EVP_PKEY *pkey, const PKCS8_PRIV_KEY_INFO *p8)

{

  const unsigned char *p, *pm;

  int pklen, pmlen;

  int ptype;

  const void *pval;

  const ASN1_STRING *pstr;

  const X509_ALGOR *palg;

  ASN1_INTEGER *privkey = NULL;

  BN_CTX *ctx = NULL;

  DSA *dsa = NULL;

  int ret = 0;

  if (!PKCS8_pkey_get0(NULL, &p, &pklen, &palg, p8))

    return 0;

  X509_ALGOR_get0(NULL, &ptype, &pval, palg);

  if (ptype != V_ASN1_SEQUENCE)

    goto decerr;

  if ((privkey = d2i_ASN1_INTEGER(NULL, &p, pklen)) == NULL)

    goto decerr;

  if (privkey->type == V_ASN1_NEG_INTEGER)

    goto decerr;

  pstr = pval;

  pm = pstr->data;

  pmlen = pstr->length;

  if (!(dsa = d2i_DSAparams(NULL, &pm, pmlen)))

    goto decerr;

  /* We have parameters now set private key */

  if (!(dsa->priv_key = ASN1_INTEGER_to_BN(privkey, NULL))) {

    DSAerror(DSA_R_BN_ERROR);

    goto dsaerr;

  }

  /* Calculate public key */

  if (!(dsa->pub_key = BN_new())) {

    DSAerror(ERR_R_MALLOC_FAILURE);

    goto dsaerr;

  }

  if (!(ctx = BN_CTX_new())) {

    DSAerror(ERR_R_MALLOC_FAILURE);

    goto dsaerr;

  }

  if (!BN_mod_exp_ct(dsa->pub_key, dsa->g, dsa->priv_key, dsa->p, ctx)) {

    DSAerror(DSA_R_BN_ERROR);

    goto dsaerr;

  }

  if (!EVP_PKEY_assign_DSA(pkey, dsa))

    goto decerr;

  ret = 1;

  goto done;

decerr:

  DSAerror(DSA_R_DECODE_ERROR);

dsaerr:

  DSA_free(dsa);

done:

  BN_CTX_free(ctx);

  ASN1_INTEGER_free(privkey);

  return ret;

}

static int

dsa_priv_encode(PKCS8_PRIV_KEY_INFO *p8, const EVP_PKEY *pkey)

{

  ASN1_STRING *params = NULL;

  ASN1_INTEGER *prkey = NULL;

  unsigned char *dp = NULL;

  int dplen;

  params = ASN1_STRING_new();

  if (!params) {

    DSAerror(ERR_R_MALLOC_FAILURE);

    goto err;

  }

  params->length = i2d_DSAparams(pkey->pkey.dsa, &params->data);

  if (params->length <= 0) {

    DSAerror(ERR_R_MALLOC_FAILURE);

    goto err;

  }

  params->type = V_ASN1_SEQUENCE;

  /* Get private key into integer */

  prkey = BN_to_ASN1_INTEGER(pkey->pkey.dsa->priv_key, NULL);

  if (!prkey) {

    DSAerror(DSA_R_BN_ERROR);

    goto err;

  }

  dplen = i2d_ASN1_INTEGER(prkey, &dp);

  ASN1_INTEGER_free(prkey);

  prkey = NULL;

  if (!PKCS8_pkey_set0(p8, OBJ_nid2obj(NID_dsa), 0, V_ASN1_SEQUENCE,

      params, dp, dplen))

    goto err;

  return 1;

err:

  free(dp);

  ASN1_STRING_free(params);

  ASN1_INTEGER_free(prkey);

  return 0;

}

static int

int_dsa_size(const EVP_PKEY *pkey)

{

  return DSA_size(pkey->pkey.dsa);

}

static int

dsa_bits(const EVP_PKEY *pkey)

{

  return BN_num_bits(pkey->pkey.dsa->p);

}

static int

dsa_security_bits(const EVP_PKEY *pkey)

{

  return DSA_security_bits(pkey->pkey.dsa);

}

static int

dsa_missing_parameters(const EVP_PKEY *pkey)

{

  DSA *dsa;

  dsa = pkey->pkey.dsa;

  if (dsa->p == NULL || dsa->q == NULL || dsa->g == NULL)

    return 1;

  return 0;

}

static int

dsa_copy_parameters(EVP_PKEY *to, const EVP_PKEY *from)

{

  BIGNUM *a;

  if ((a = BN_dup(from->pkey.dsa->p)) == NULL)

    return 0;

  BN_free(to->pkey.dsa->p);

  to->pkey.dsa->p = a;

  if ((a = BN_dup(from->pkey.dsa->q)) == NULL)

    return 0;

  BN_free(to->pkey.dsa->q);

  to->pkey.dsa->q = a;

  if ((a = BN_dup(from->pkey.dsa->g)) == NULL)

    return 0;

  BN_free(to->pkey.dsa->g);

  to->pkey.dsa->g = a;

  return 1;

}

static int

dsa_cmp_parameters(const EVP_PKEY *a, const EVP_PKEY *b)

{

  if (BN_cmp(a->pkey.dsa->p, b->pkey.dsa->p) ||

      BN_cmp(a->pkey.dsa->q, b->pkey.dsa->q) ||

      BN_cmp(a->pkey.dsa->g, b->pkey.dsa->g))

    return 0;

  else

    return 1;

}

static int

dsa_pub_cmp(const EVP_PKEY *a, const EVP_PKEY *b)

{

  if (BN_cmp(b->pkey.dsa->pub_key, a->pkey.dsa->pub_key) != 0)

    return 0;

  else

    return 1;

}

static void

int_dsa_free(EVP_PKEY *pkey)

{

  DSA_free(pkey->pkey.dsa);

}

static void

update_buflen(const BIGNUM *b, size_t *pbuflen)

{

  size_t i;

  if (!b)

    return;

  if (*pbuflen < (i = (size_t)BN_num_bytes(b)))

    *pbuflen = i;

}

static int

do_dsa_print(BIO *bp, const DSA *x, int off, int ptype)

{

  unsigned char *m = NULL;

  int ret = 0;

  size_t buf_len = 0;

  const char *ktype = NULL;

  const BIGNUM *priv_key, *pub_key;

  if (ptype == 2)

    priv_key = x->priv_key;

  else

    priv_key = NULL;

  if (ptype > 0)

    pub_key = x->pub_key;

  else

    pub_key = NULL;

  if (ptype == 2)

    ktype = "Private-Key";

  else if (ptype == 1)

    ktype = "Public-Key";

  else

    ktype = "DSA-Parameters";

  update_buflen(x->p, &buf_len);

  update_buflen(x->q, &buf_len);

  update_buflen(x->g, &buf_len);

  update_buflen(priv_key, &buf_len);

  update_buflen(pub_key, &buf_len);

  m = malloc(buf_len + 10);

  if (m == NULL) {

    DSAerror(ERR_R_MALLOC_FAILURE);

    goto err;

  }

  if (priv_key) {

    if (!BIO_indent(bp, off, 128))

      goto err;

    if (BIO_printf(bp, "%s: (%d bit)\n", ktype,

        BN_num_bits(x->p)) <= 0)

      goto err;

  }

  if (!ASN1_bn_print(bp, "priv:", priv_key, m, off))

    goto err;

  if (!ASN1_bn_print(bp, "pub: ", pub_key, m, off))

    goto err;

  if (!ASN1_bn_print(bp, "P:   ", x->p, m, off))

    goto err;

  if (!ASN1_bn_print(bp, "Q:   ", x->q, m, off))

    goto err;

  if (!ASN1_bn_print(bp, "G:   ", x->g, m, off))

    goto err;

  ret = 1;

err:

  free(m);

  return ret;

}

static int

dsa_param_decode(EVP_PKEY *pkey, const unsigned char **pder, int derlen)

{

  DSA *dsa;

  if (!(dsa = d2i_DSAparams(NULL, pder, derlen))) {

    DSAerror(ERR_R_DSA_LIB);

    return 0;

  }

  EVP_PKEY_assign_DSA(pkey, dsa);

  return 1;

}

static int

dsa_param_encode(const EVP_PKEY *pkey, unsigned char **pder)

{

  return i2d_DSAparams(pkey->pkey.dsa, pder);

}

static int

dsa_param_print(BIO *bp, const EVP_PKEY *pkey, int indent, ASN1_PCTX *ctx)

{

  return do_dsa_print(bp, pkey->pkey.dsa, indent, 0);

}

static int

dsa_pub_print(BIO *bp, const EVP_PKEY *pkey, int indent, ASN1_PCTX *ctx)

{

  return do_dsa_print(bp, pkey->pkey.dsa, indent, 1);

}

static int

dsa_priv_print(BIO *bp, const EVP_PKEY *pkey, int indent, ASN1_PCTX *ctx)

{

  return do_dsa_print(bp, pkey->pkey.dsa, indent, 2);

}

static int

old_dsa_priv_decode(EVP_PKEY *pkey, const unsigned char **pder, int derlen)

{

  DSA *dsa;

  BN_CTX *ctx = NULL;

  BIGNUM *j, *p1, *newp1, *powg;

  int qbits;

  if (!(dsa = d2i_DSAPrivateKey(NULL, pder, derlen))) {

    DSAerror(ERR_R_DSA_LIB);

    return 0;

  }

  /* FIPS 186-3 allows only three different sizes for q. */

  qbits = BN_num_bits(dsa->q);

  if (qbits != 160 && qbits != 224 && qbits != 256) {

    DSAerror(DSA_R_BAD_Q_VALUE);

    goto err;

  }

  if (BN_num_bits(dsa->p) > OPENSSL_DSA_MAX_MODULUS_BITS) {

    DSAerror(DSA_R_MODULUS_TOO_LARGE);

    goto err;

  }

  /* Check that 1 < g < p. */

  if (BN_cmp(dsa->g, BN_value_one()) <= 0 ||

      BN_cmp(dsa->g, dsa->p) >= 0) {

    DSAerror(DSA_R_PARAMETER_ENCODING_ERROR); /* XXX */

    goto err;

  }

  ctx = BN_CTX_new();

  if (ctx == NULL)

    goto err;

  /*

   * Check that p and q are consistent with each other.

   */

  j = BN_CTX_get(ctx);

  p1 = BN_CTX_get(ctx);

  newp1 = BN_CTX_get(ctx);

  powg = BN_CTX_get(ctx);

  if (j == NULL || p1 == NULL || newp1 == NULL || powg == NULL)

    goto err;

  /* p1 = p - 1 */

  if (BN_sub(p1, dsa->p, BN_value_one()) == 0)

    goto err;

  /* j = (p - 1) / q */

  if (BN_div_ct(j, NULL, p1, dsa->q, ctx) == 0)

    goto err;

  /* q * j should == p - 1 */

  if (BN_mul(newp1, dsa->q, j, ctx) == 0)

    goto err;

  if (BN_cmp(newp1, p1) != 0) {

    DSAerror(DSA_R_BAD_Q_VALUE);

    goto err;

  }

  /*

   * Check that g generates a multiplicative subgroup of order q.

   * We only check that g^q == 1, so the order is a divisor of q.

   * Once we know that q is prime, this is enough.

   */

  if (!BN_mod_exp_ct(powg, dsa->g, dsa->q, dsa->p, ctx))

    goto err;

  if (BN_cmp(powg, BN_value_one()) != 0) {

    DSAerror(DSA_R_PARAMETER_ENCODING_ERROR); /* XXX */

    goto err;

  }

  /*

   * Check that q is not a composite number.

   */

  if (BN_is_prime_ex(dsa->q, BN_prime_checks, ctx, NULL) <= 0) {

    DSAerror(DSA_R_BAD_Q_VALUE);

    goto err;

  }

  BN_CTX_free(ctx);

  EVP_PKEY_assign_DSA(pkey, dsa);

  return 1;

 err:

  BN_CTX_free(ctx);

  DSA_free(dsa);

  return 0;

}

static int

old_dsa_priv_encode(const EVP_PKEY *pkey, unsigned char **pder)

{

  return i2d_DSAPrivateKey(pkey->pkey.dsa, pder);

}

static int

dsa_sig_print(BIO *bp, const X509_ALGOR *sigalg, const ASN1_STRING *sig,

    int indent, ASN1_PCTX *pctx)

{

  DSA_SIG *dsa_sig;

  const unsigned char *p;

  if (!sig) {

    if (BIO_puts(bp, "\n") <= 0)

      return 0;

    else

      return 1;

  }

  p = sig->data;

  dsa_sig = d2i_DSA_SIG(NULL, &p, sig->length);

  if (dsa_sig) {

    int rv = 0;

    size_t buf_len = 0;

    unsigned char *m = NULL;

    update_buflen(dsa_sig->r, &buf_len);

    update_buflen(dsa_sig->s, &buf_len);

    m = malloc(buf_len + 10);

    if (m == NULL) {

      DSAerror(ERR_R_MALLOC_FAILURE);

      goto err;

    }

    if (BIO_write(bp, "\n", 1) != 1)

      goto err;

    if (!ASN1_bn_print(bp, "r:   ", dsa_sig->r, m, indent))

      goto err;

    if (!ASN1_bn_print(bp, "s:   ", dsa_sig->s, m, indent))

      goto err;

    rv = 1;

err:

    free(m);

    DSA_SIG_free(dsa_sig);

    return rv;

  }

  return X509_signature_dump(bp, sig, indent);

}

static int

dsa_pkey_ctrl(EVP_PKEY *pkey, int op, long arg1, void *arg2)

{

  switch (op) {

  case ASN1_PKEY_CTRL_PKCS7_SIGN:

    if (arg1 == 0) {

      int snid, hnid;

      X509_ALGOR *alg1, *alg2;

      PKCS7_SIGNER_INFO_get0_algs(arg2, NULL, &alg1, &alg2);

      if (alg1 == NULL || alg1->algorithm == NULL)

        return -1;

      hnid = OBJ_obj2nid(alg1->algorithm);

      if (hnid == NID_undef)

        return -1;

      if (!OBJ_find_sigid_by_algs(&snid, hnid,

          EVP_PKEY_id(pkey)))

        return -1;

      X509_ALGOR_set0(alg2, OBJ_nid2obj(snid), V_ASN1_UNDEF,

          0);

    }

    return 1;

#ifndef OPENSSL_NO_CMS

  case ASN1_PKEY_CTRL_CMS_SIGN:

    if (arg1 == 0) {

      int snid, hnid;

      X509_ALGOR *alg1, *alg2;

      CMS_SignerInfo_get0_algs(arg2, NULL, NULL, &alg1, &alg2);

      if (alg1 == NULL || alg1->algorithm == NULL)

        return -1;

      hnid = OBJ_obj2nid(alg1->algorithm);

      if (hnid == NID_undef)

        return -1;

      if (!OBJ_find_sigid_by_algs(&snid, hnid, EVP_PKEY_id(pkey)))

        return -1;

      X509_ALGOR_set0(alg2, OBJ_nid2obj(snid), V_ASN1_UNDEF, 0);

    }

    return 1;

  case ASN1_PKEY_CTRL_CMS_RI_TYPE:

    *(int *)arg2 = CMS_RECIPINFO_NONE;

    return 1;

#endif

  case ASN1_PKEY_CTRL_DEFAULT_MD_NID:

    *(int *)arg2 = NID_sha1;

    return 2;

  default:

    return -2;

  }

}

/* NB these are sorted in pkey_id order, lowest first */

const EVP_PKEY_ASN1_METHOD dsa_asn1_meths[] = {

  {

    .pkey_id = EVP_PKEY_DSA2,

    .pkey_base_id = EVP_PKEY_DSA,

    .pkey_flags = ASN1_PKEY_ALIAS

  },

  {

    .pkey_id = EVP_PKEY_DSA1,

    .pkey_base_id = EVP_PKEY_DSA,

    .pkey_flags = ASN1_PKEY_ALIAS

  },

  {

    .pkey_id = EVP_PKEY_DSA4,

    .pkey_base_id = EVP_PKEY_DSA,

    .pkey_flags = ASN1_PKEY_ALIAS

  },

  {

    .pkey_id = EVP_PKEY_DSA3,

    .pkey_base_id = EVP_PKEY_DSA,

    .pkey_flags = ASN1_PKEY_ALIAS

  },

  {

    .pkey_id = EVP_PKEY_DSA,

    .pkey_base_id = EVP_PKEY_DSA,

    .pem_str = "DSA",

    .info = "OpenSSL DSA method",

    .pub_decode = dsa_pub_decode,

    .pub_encode = dsa_pub_encode,

    .pub_cmp = dsa_pub_cmp,

    .pub_print = dsa_pub_print,

    .priv_decode = dsa_priv_decode,

    .priv_encode = dsa_priv_encode,

    .priv_print = dsa_priv_print,

    .pkey_size = int_dsa_size,

    .pkey_bits = dsa_bits,

    .pkey_security_bits = dsa_security_bits,

    .param_decode = dsa_param_decode,

    .param_encode = dsa_param_encode,

    .param_missing = dsa_missing_parameters,

    .param_copy = dsa_copy_parameters,

    .param_cmp = dsa_cmp_parameters,

    .param_print = dsa_param_print,

    .sig_print = dsa_sig_print,

    .pkey_free = int_dsa_free,

    .pkey_ctrl = dsa_pkey_ctrl,

    .old_priv_decode = old_dsa_priv_decode,

    .old_priv_encode = old_dsa_priv_encode

  }

};