/**

 * FreeRDP: A Remote Desktop Protocol Implementation

 * ASN1 routines for RDPEAR

 *

 * Copyright 2024 David Fort <contact@hardening-consulting.com>

 *

 * 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 <rdpear-common/rdpear_asn1.h>

#include <winpr/asn1.h>

wStream* rdpear_enc_Checksum(UINT32 cksumtype, krb5_checksum* csum)

{

  /**

   * Checksum        ::= SEQUENCE {

   *   cksumtype       [0] Int32,

   *   checksum        [1] OCTET STRING

   * }

   */

  wStream* ret = NULL;

  WinPrAsn1Encoder* enc = WinPrAsn1Encoder_New(WINPR_ASN1_DER);

  if (!enc)

    return NULL;

  if (!WinPrAsn1EncSeqContainer(enc))

    goto out;

  if (!WinPrAsn1EncContextualInteger(enc, 0, (WinPrAsn1_INTEGER)cksumtype))

    goto out;

  WinPrAsn1_OctetString octets;

  octets.data = (BYTE*)csum->contents;

  octets.len = csum->length;

  if (!WinPrAsn1EncContextualOctetString(enc, 1, &octets) || !WinPrAsn1EncEndContainer(enc))

    goto out;

  ret = Stream_New(NULL, 1024);

  if (!ret)

    goto out;

  if (!WinPrAsn1EncToStream(enc, ret))

  {

    Stream_Free(ret, TRUE);

    ret = NULL;

    goto out;

  }

out:

  WinPrAsn1Encoder_Free(&enc);

  return ret;

}

wStream* rdpear_enc_EncryptedData(UINT32 encType, krb5_data* payload)

{

  /**

   * EncryptedData   ::= SEQUENCE {

   *   etype   [0] Int32 -- EncryptionType --,

   *   kvno    [1] UInt32 OPTIONAL,

   *   cipher  [2] OCTET STRING -- ciphertext

   *  }

   */

  wStream* ret = NULL;

  WinPrAsn1Encoder* enc = WinPrAsn1Encoder_New(WINPR_ASN1_DER);

  if (!enc)

    return NULL;

  if (!WinPrAsn1EncSeqContainer(enc))

    goto out;

  if (!WinPrAsn1EncContextualInteger(enc, 0, (WinPrAsn1_INTEGER)encType))

    goto out;

  WinPrAsn1_OctetString octets;

  octets.data = (BYTE*)payload->data;

  octets.len = payload->length;

  if (!WinPrAsn1EncContextualOctetString(enc, 2, &octets) || !WinPrAsn1EncEndContainer(enc))

    goto out;

  ret = Stream_New(NULL, 1024);

  if (!ret)

    goto out;

  if (!WinPrAsn1EncToStream(enc, ret))

  {

    Stream_Free(ret, TRUE);

    ret = NULL;

    goto out;

  }

out:

  WinPrAsn1Encoder_Free(&enc);

  return ret;

}