/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
 * project 2006.
 */
/* ====================================================================
 * Copyright (c) 2006,2007 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 <openssl/evp.h>

#include <openssl/digest.h>
#include <openssl/err.h>

#include "internal.h"
#include "../digest/internal.h"


/* md_begin_digset is a callback from the |EVP_MD_CTX| code that is called when
 * a new digest is begun. */
static int md_begin_digest(EVP_MD_CTX *ctx) {
  int r = EVP_PKEY_CTX_ctrl(ctx->pctx, -1, EVP_PKEY_OP_TYPE_SIG,
                            EVP_PKEY_CTRL_DIGESTINIT, 0, ctx);
  return r > 0 || r == -2;
}

static const struct evp_md_pctx_ops md_pctx_ops = {
  EVP_PKEY_CTX_free,
  EVP_PKEY_CTX_dup,
  md_begin_digest,
};

static int do_sigver_init(EVP_MD_CTX *ctx, EVP_PKEY_CTX **pctx,
                          const EVP_MD *type, ENGINE *e, EVP_PKEY *pkey,
                          int is_verify) {
  if (ctx->pctx == NULL) {
    ctx->pctx = EVP_PKEY_CTX_new(pkey, e);
  }
  if (ctx->pctx == NULL) {
    return 0;
  }
  ctx->pctx_ops = &md_pctx_ops;

  if (type == NULL) {
    type = EVP_sha1();
  }

  if (type == NULL) {
    OPENSSL_PUT_ERROR(EVP, do_sigver_init, EVP_R_NO_DEFAULT_DIGEST);
    return 0;
  }

  if (is_verify) {
    if (ctx->pctx->pmeth->verifyctx_init) {
      if (ctx->pctx->pmeth->verifyctx_init(ctx->pctx, ctx) <= 0) {
        return 0;
      }
      ctx->pctx->operation = EVP_PKEY_OP_VERIFYCTX;
    } else if (EVP_PKEY_verify_init(ctx->pctx) <= 0) {
      return 0;
    }
  } else {
    if (ctx->pctx->pmeth->signctx_init) {
      if (ctx->pctx->pmeth->signctx_init(ctx->pctx, ctx) <= 0) {
        return 0;
      }
      ctx->pctx->operation = EVP_PKEY_OP_SIGNCTX;
    } else if (EVP_PKEY_sign_init(ctx->pctx) <= 0) {
      return 0;
    }
  }
  if (EVP_PKEY_CTX_set_signature_md(ctx->pctx, type) <= 0) {
    return 0;
  }
  if (pctx) {
    *pctx = ctx->pctx;
  }
  if (!EVP_DigestInit_ex(ctx, type, e)) {
    return 0;
  }
  return 1;
}

int EVP_DigestSignInit(EVP_MD_CTX *ctx, EVP_PKEY_CTX **pctx, const EVP_MD *type,
                       ENGINE *e, EVP_PKEY *pkey) {
  return do_sigver_init(ctx, pctx, type, e, pkey, 0);
}

int EVP_DigestVerifyInit(EVP_MD_CTX *ctx, EVP_PKEY_CTX **pctx,
                         const EVP_MD *type, ENGINE *e, EVP_PKEY *pkey) {
  return do_sigver_init(ctx, pctx, type, e, pkey, 1);
}

int EVP_DigestSignUpdate(EVP_MD_CTX *ctx, const void *data, size_t len) {
  return EVP_DigestUpdate(ctx, data, len);
}

int EVP_DigestVerifyUpdate(EVP_MD_CTX *ctx, const void *data, size_t len) {
  return EVP_DigestUpdate(ctx, data, len);
}

int EVP_DigestSignFinal(EVP_MD_CTX *ctx, uint8_t *out_sig,
                        size_t *out_sig_len) {
  int r = 0;
  const int has_signctx = ctx->pctx->pmeth->signctx != NULL;

  if (out_sig) {
    EVP_MD_CTX tmp_ctx;
    uint8_t md[EVP_MAX_MD_SIZE];
    unsigned int mdlen;

    EVP_MD_CTX_init(&tmp_ctx);
    if (!EVP_MD_CTX_copy_ex(&tmp_ctx, ctx)) {
      return 0;
    }
    if (has_signctx) {
      r = tmp_ctx.pctx->pmeth->signctx(tmp_ctx.pctx, out_sig, out_sig_len, &tmp_ctx);
    } else {
      r = EVP_DigestFinal_ex(&tmp_ctx, md, &mdlen);
    }
    EVP_MD_CTX_cleanup(&tmp_ctx);
    if (has_signctx || !r) {
      return r;
    }
    return EVP_PKEY_sign(ctx->pctx, out_sig, out_sig_len, md, mdlen);
  } else {
    if (has_signctx) {
      return ctx->pctx->pmeth->signctx(ctx->pctx, out_sig, out_sig_len, ctx);
    } else {
      size_t s = EVP_MD_size(ctx->digest);
      return EVP_PKEY_sign(ctx->pctx, out_sig, out_sig_len, NULL, s);
    }
  }
}

int EVP_DigestVerifyFinal(EVP_MD_CTX *ctx, const uint8_t *sig,
                          size_t sig_len) {
  EVP_MD_CTX tmp_ctx;
  uint8_t md[EVP_MAX_MD_SIZE];
  int r;
  unsigned int mdlen;
  const int has_verifyctx = ctx->pctx->pmeth->verifyctx != NULL;

  EVP_MD_CTX_init(&tmp_ctx);
  if (!EVP_MD_CTX_copy_ex(&tmp_ctx, ctx)) {
    return 0;
  }
  if (has_verifyctx) {
    r = tmp_ctx.pctx->pmeth->verifyctx(tmp_ctx.pctx, sig, sig_len, &tmp_ctx);
  } else {
    r = EVP_DigestFinal_ex(&tmp_ctx, md, &mdlen);
  }

  EVP_MD_CTX_cleanup(&tmp_ctx);
  if (has_verifyctx || !r) {
    return r;
  }
  return EVP_PKEY_verify(ctx->pctx, sig, sig_len, md, mdlen);
}