// Copyright 2006-2016 The OpenSSL Project Authors. All Rights Reserved.

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

//     https://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

#include <assert.h>

#include <openssl/err.h>

#include <openssl/evp.h>

#include "../../evp/internal.h"

#include "../delocate.h"

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

#include "../service_indicator/internal.h"

using namespace bssl;

enum evp_sign_verify_t {

  evp_sign,

  evp_verify,

};

DEFINE_LOCAL_DATA(struct evp_md_pctx_ops, md_pctx_ops) {

  out->free = EVP_PKEY_CTX_free;

  out->dup = EVP_PKEY_CTX_dup;

}

static int uses_prehash(EVP_PKEY_CTX *pctx, enum evp_sign_verify_t op) {

  return (op == evp_sign) ? (FromOpaque(pctx)->pmeth->sign != nullptr)

                          : (FromOpaque(pctx)->pmeth->verify != nullptr);

}

static int do_sigver_init(EVP_MD_CTX *ctx, EVP_PKEY_CTX **out_pctx,

                          const EVP_MD *type, ENGINE *e, const EVP_PKEY *pkey,

                          enum evp_sign_verify_t op) {

  UniquePtr<EVP_PKEY_CTX> pctx(EVP_PKEY_CTX_new(pkey, e));

  if (pctx == nullptr) {

    return 0;

  }

  if (op == evp_verify) {

    if (!EVP_PKEY_verify_init(pctx.get())) {

      return 0;

    }

  } else {

    if (!EVP_PKEY_sign_init(pctx.get())) {

      return 0;

    }

  }

  if (type != nullptr && !EVP_PKEY_CTX_set_signature_md(pctx.get(), type)) {

    return 0;

  }

  if (uses_prehash(pctx.get(), op)) {

    if (type == nullptr) {

      OPENSSL_PUT_ERROR(EVP, EVP_R_NO_DEFAULT_DIGEST);

      return 0;

    }

    if (!EVP_DigestInit_ex(ctx, type, e)) {

      return 0;

    }

  } else {

    EVP_MD_CTX_reset(ctx);

  }

  assert(ctx->pctx == nullptr);

  ctx->pctx_ops = md_pctx_ops();

  ctx->pctx = pctx.release();

  if (out_pctx) {

    *out_pctx = ctx->pctx;

  }

  return 1;

}

int EVP_DigestSignInit(EVP_MD_CTX *ctx, EVP_PKEY_CTX **pctx, const EVP_MD *type,

                       ENGINE *e, const EVP_PKEY *pkey) {

  return do_sigver_init(ctx, pctx, type, e, pkey, evp_sign);

}

int EVP_DigestVerifyInit(EVP_MD_CTX *ctx, EVP_PKEY_CTX **pctx,

                         const EVP_MD *type, ENGINE *e, const EVP_PKEY *pkey) {

  return do_sigver_init(ctx, pctx, type, e, pkey, evp_verify);

}

int EVP_DigestSignUpdate(EVP_MD_CTX *ctx, const void *data, size_t len) {

  if (!uses_prehash(ctx->pctx, evp_sign)) {

    OPENSSL_PUT_ERROR(EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);

    return 0;

  }

  return EVP_DigestUpdate(ctx, data, len);

}

int EVP_DigestVerifyUpdate(EVP_MD_CTX *ctx, const void *data, size_t len) {

  if (!uses_prehash(ctx->pctx, evp_verify)) {

    OPENSSL_PUT_ERROR(EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);

    return 0;

  }

  return EVP_DigestUpdate(ctx, data, len);

}

int EVP_DigestSignFinal(EVP_MD_CTX *ctx, uint8_t *out_sig,

                        size_t *out_sig_len) {

  if (!uses_prehash(ctx->pctx, evp_sign)) {

    OPENSSL_PUT_ERROR(EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);

    return 0;

  }

  if (out_sig) {

    EVP_MD_CTX tmp_ctx;

    int ret;

    uint8_t md[EVP_MAX_MD_SIZE];

    unsigned int mdlen;

    FIPS_service_indicator_lock_state();

    EVP_MD_CTX_init(&tmp_ctx);

    ret = EVP_MD_CTX_copy_ex(&tmp_ctx, ctx) &&

          EVP_DigestFinal_ex(&tmp_ctx, md, &mdlen) &&

          EVP_PKEY_sign(ctx->pctx, out_sig, out_sig_len, md, mdlen);

    EVP_MD_CTX_cleanup(&tmp_ctx);

    FIPS_service_indicator_unlock_state();

    if (ret) {

      EVP_DigestSign_verify_service_indicator(ctx);

    }

    return ret;

  } else {

    size_t s = EVP_MD_size(ctx->digest);

    return EVP_PKEY_sign(ctx->pctx, out_sig, out_sig_len, nullptr, s);

  }

}

int EVP_DigestVerifyFinal(EVP_MD_CTX *ctx, const uint8_t *sig, size_t sig_len) {

  if (!uses_prehash(ctx->pctx, evp_verify)) {

    OPENSSL_PUT_ERROR(EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);

    return 0;

  }

  EVP_MD_CTX tmp_ctx;

  int ret;

  uint8_t md[EVP_MAX_MD_SIZE];

  unsigned int mdlen;

  FIPS_service_indicator_lock_state();

  EVP_MD_CTX_init(&tmp_ctx);

  ret = EVP_MD_CTX_copy_ex(&tmp_ctx, ctx) &&

        EVP_DigestFinal_ex(&tmp_ctx, md, &mdlen) &&

        EVP_PKEY_verify(ctx->pctx, sig, sig_len, md, mdlen);

  FIPS_service_indicator_unlock_state();

  EVP_MD_CTX_cleanup(&tmp_ctx);

  if (ret) {

    EVP_DigestVerify_verify_service_indicator(ctx);

  }

  return ret;

}

int EVP_DigestSign(EVP_MD_CTX *ctx, uint8_t *out_sig, size_t *out_sig_len,

                   const uint8_t *data, size_t data_len) {

  FIPS_service_indicator_lock_state();

  int ret = 0;

  if (uses_prehash(ctx->pctx, evp_sign)) {

    // If `out_sig` is NULL, the caller is only querying the maximum output

    // length. `data` should only be incorporated in the final call.

    if (out_sig != nullptr && !EVP_DigestSignUpdate(ctx, data, data_len)) {

      goto end;

    }

    ret = EVP_DigestSignFinal(ctx, out_sig, out_sig_len);

    goto end;

  }

  if (FromOpaque(ctx->pctx)->pmeth->sign_message == nullptr) {

    OPENSSL_PUT_ERROR(EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);

    goto end;

  }

  ret = FromOpaque(ctx->pctx)->pmeth->sign_message(

      FromOpaque(ctx->pctx), out_sig, out_sig_len, data, data_len);

end:

  FIPS_service_indicator_unlock_state();

  if (ret) {

    EVP_DigestSign_verify_service_indicator(ctx);

  }

  return ret;

}

int EVP_DigestVerify(EVP_MD_CTX *ctx, const uint8_t *sig, size_t sig_len,

                     const uint8_t *data, size_t len) {

  FIPS_service_indicator_lock_state();

  int ret = 0;

  if (uses_prehash(ctx->pctx, evp_verify)) {

    ret = EVP_DigestVerifyUpdate(ctx, data, len) &&

          EVP_DigestVerifyFinal(ctx, sig, sig_len);

    goto end;

  }

  if (FromOpaque(ctx->pctx)->pmeth->verify_message == nullptr) {

    OPENSSL_PUT_ERROR(EVP, EVP_R_OPERATION_NOT_SUPPORTED_FOR_THIS_KEYTYPE);

    goto end;

  }

  ret = FromOpaque(ctx->pctx)->pmeth->verify_message(FromOpaque(ctx->pctx), sig,

                                                     sig_len, data, len);

end:

  FIPS_service_indicator_unlock_state();

  if (ret) {

    EVP_DigestVerify_verify_service_indicator(ctx);

  }

  return ret;

}