/**

 * FreeRDP: A Remote Desktop Protocol Implementation

 * Certificate Handling

 *

 * Copyright 2011 Jiten Pathy

 * Copyright 2011 Marc-Andre Moreau <marcandre.moreau@gmail.com>

 * Copyright 2015 Thincast Technologies GmbH

 * Copyright 2015 DI (FH) Martin Haimberger <martin.haimberger@thincast.com>

 * Copyright 2023 Armin Novak <anovak@thincast.com>

 * Copyright 2023 Thincast Technologies GmbH

 *

 * 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

 *

 *     http://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 <freerdp/config.h>

#include <errno.h>

#include <stdio.h>

#include <string.h>

#include <winpr/assert.h>

#include <winpr/wtypes.h>

#include <winpr/crt.h>

#include <winpr/file.h>

#include <winpr/crypto.h>

#include <openssl/pem.h>

#include <openssl/rsa.h>

#include <openssl/bn.h>

#include "cert_common.h"

#include "crypto.h"

#include "opensslcompat.h"

#define TAG FREERDP_TAG("core")

static BOOL cert_info_allocate(rdpCertInfo* info, size_t size);

BOOL read_bignum(BYTE** dst, DWORD* length, const BIGNUM* num, BOOL alloc)

{

  WINPR_ASSERT(dst);

  WINPR_ASSERT(length);

  WINPR_ASSERT(num);

  if (alloc)

  {

    free(*dst);

    *dst = NULL;

    *length = 0;

  }

  const int len = BN_num_bytes(num);

  if (len < 0)

    return FALSE;

  if (!alloc)

  {

    if (*length < (UINT32)len)

      return FALSE;

  }

  if (len > 0)

  {

    if (alloc)

    {

      *dst = malloc((size_t)len);

      if (!*dst)

        return FALSE;

    }

    BN_bn2bin(num, *dst);

    crypto_reverse(*dst, (size_t)len);

    *length = (UINT32)len;

  }

  return TRUE;

}

BOOL cert_info_create(rdpCertInfo* dst, const BIGNUM* rsa, const BIGNUM* rsa_e)

{

  const rdpCertInfo empty = { 0 };

  WINPR_ASSERT(dst);

  WINPR_ASSERT(rsa);

  *dst = empty;

  if (!read_bignum(&dst->Modulus, &dst->ModulusLength, rsa, TRUE))

    goto fail;

  {

    DWORD len = sizeof(dst->exponent);

    BYTE* ptr = &dst->exponent[0];

    if (!read_bignum(&ptr, &len, rsa_e, FALSE))

      goto fail;

  }

  return TRUE;

fail:

  cert_info_free(dst);

  return FALSE;

}

BOOL cert_info_clone(rdpCertInfo* dst, const rdpCertInfo* src)

{

  WINPR_ASSERT(dst);

  WINPR_ASSERT(src);

  *dst = *src;

  dst->Modulus = NULL;

  dst->ModulusLength = 0;

  if (src->ModulusLength > 0)

  {

    dst->Modulus = malloc(src->ModulusLength);

    if (!dst->Modulus)

      return FALSE;

    memcpy(dst->Modulus, src->Modulus, src->ModulusLength);

    dst->ModulusLength = src->ModulusLength;

  }

  return TRUE;

}

void cert_info_free(rdpCertInfo* info)

{

  WINPR_ASSERT(info);

  free(info->Modulus);

  info->ModulusLength = 0;

  info->Modulus = NULL;

}

BOOL cert_info_allocate(rdpCertInfo* info, size_t size)

{

  WINPR_ASSERT(info);

  cert_info_free(info);

  info->Modulus = (BYTE*)malloc(size);

  if (!info->Modulus && (size > 0))

  {

    WLog_ERR(TAG, "Failed to allocate info->Modulus of size %" PRIuz, size);

    return FALSE;

  }

  info->ModulusLength = (UINT32)size;

  return TRUE;

}

BOOL cert_info_read_modulus(rdpCertInfo* info, size_t size, wStream* s)

{

  if (!Stream_CheckAndLogRequiredLength(TAG, s, size))

    return FALSE;

  if (size > UINT32_MAX)

  {

    WLog_ERR(TAG, "modulus size %" PRIuz " exceeds limit of %" PRIu32, size, UINT32_MAX);

    return FALSE;

  }

  if (!cert_info_allocate(info, size))

    return FALSE;

  Stream_Read(s, info->Modulus, info->ModulusLength);

  return TRUE;

}

BOOL cert_info_read_exponent(rdpCertInfo* info, size_t size, wStream* s)

{

  if (!Stream_CheckAndLogRequiredLength(TAG, s, size))

    return FALSE;

  if (size > 4)

  {

    WLog_ERR(TAG, "exponent size %" PRIuz " exceeds limit of %" PRIu32, size, 4);

    return FALSE;

  }

  if (!info->Modulus || (info->ModulusLength == 0))

  {

    WLog_ERR(TAG, "invalid modulus=%p [%" PRIu32 "]", info->Modulus, info->ModulusLength);

    return FALSE;

  }

  Stream_Read(s, &info->exponent[4 - size], size);

  crypto_reverse(info->Modulus, info->ModulusLength);

  crypto_reverse(info->exponent, 4);

  return TRUE;

}

#if !defined(OPENSSL_VERSION_MAJOR) || (OPENSSL_VERSION_MAJOR < 3)

X509* x509_from_rsa(const RSA* rsa)

{

  EVP_PKEY* pubkey = NULL;

  X509* x509 = NULL;

  BIO* bio = BIO_new(

#if defined(LIBRESSL_VERSION_NUMBER)

      BIO_s_mem()

#else

      BIO_s_secmem()

#endif

  );

  if (!bio)

  {

    WLog_ERR(TAG, "BIO_new() failed");

    return NULL;

  }

  const int rc = PEM_write_bio_RSA_PUBKEY(bio, (RSA*)rsa);

  if (rc != 1)

  {

    WLog_ERR(TAG, "PEM_write_bio_RSA_PUBKEY(bio, (RSA*)rsa) failed");

    goto fail;

  }

  pubkey = PEM_read_bio_PUBKEY(bio, NULL, NULL, NULL);

  if (!pubkey)

  {

    WLog_ERR(TAG, "PEM_read_bio_PUBKEY(bio, NULL, NULL, NULL) failed");

    goto fail;

  }

  x509 = X509_new();

  if (!x509)

  {

    WLog_ERR(TAG, "X509_new() failed");

    goto fail;

  }

  const int res = X509_set_pubkey(x509, pubkey);

  if (res != 1)

  {

    WLog_ERR(TAG, "X509_set_pubkey(x509, pubkey) failed");

    X509_free(x509);

    x509 = NULL;

    goto fail;

  }

fail:

  BIO_free_all(bio);

  EVP_PKEY_free(pubkey);

  return x509;

}

#endif