text: /* $OpenBSD: dsa_pmeth.c,v 1.11 2017/01/29 17:49:22 beck 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 "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_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
  };
  