/**

 * FreeRDP: A Remote Desktop Protocol Client

 * Kerberos Auth Protocol

 *

 * Copyright 2022 Isaac Klein <fifthdegree@protonmail.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.

 */

#ifndef WITH_KRB5_MIT

#error "This file must only be included with MIT kerberos"

#endif

#include <string.h>

#include <winpr/path.h>

#include <winpr/wlog.h>

#include <winpr/endian.h>

#include <winpr/crypto.h>

#include <winpr/print.h>

#include <winpr/assert.h>

#include <errno.h>

#include "krb5glue.h"

#include <profile.h>

static char* create_temporary_file(void)

{

  BYTE buffer[32];

  char* hex = NULL;

  char* path = NULL;

  winpr_RAND(buffer, sizeof(buffer));

  hex = winpr_BinToHexString(buffer, sizeof(buffer), FALSE);

  path = GetKnownSubPath(KNOWN_PATH_TEMP, hex);

  free(hex);

  return path;

}

void krb5glue_keys_free(krb5_context ctx, struct krb5glue_keyset* keyset)

{

  WINPR_ASSERT(ctx);

  WINPR_ASSERT(keyset);

  krb5_k_free_key(ctx, keyset->session_key);

  krb5_k_free_key(ctx, keyset->initiator_key);

  krb5_k_free_key(ctx, keyset->acceptor_key);

}

krb5_error_code krb5glue_update_keyset(krb5_context ctx, krb5_auth_context auth_ctx, BOOL acceptor,

                                       struct krb5glue_keyset* keyset)

{

  WINPR_ASSERT(ctx);

  WINPR_ASSERT(auth_ctx);

  WINPR_ASSERT(keyset);

  krb5glue_keys_free(ctx, keyset);

  krb5_auth_con_getkey_k(ctx, auth_ctx, &keyset->session_key);

  if (acceptor)

  {

    krb5_auth_con_getsendsubkey_k(ctx, auth_ctx, &keyset->acceptor_key);

    krb5_auth_con_getrecvsubkey_k(ctx, auth_ctx, &keyset->initiator_key);

  }

  else

  {

    krb5_auth_con_getsendsubkey_k(ctx, auth_ctx, &keyset->initiator_key);

    krb5_auth_con_getrecvsubkey_k(ctx, auth_ctx, &keyset->acceptor_key);

  }

  return 0;

}

krb5_prompt_type krb5glue_get_prompt_type(krb5_context ctx, krb5_prompt prompts[], int index)

{

  WINPR_ASSERT(ctx);

  WINPR_ASSERT(prompts);

  krb5_prompt_type* types = krb5_get_prompt_types(ctx);

  return types ? types[index] : 0;

}

krb5_error_code krb5glue_log_error(krb5_context ctx, krb5_data* msg, const char* tag)

{

  krb5_error* error = NULL;

  krb5_error_code rv = 0;

  WINPR_ASSERT(ctx);

  WINPR_ASSERT(msg);

  WINPR_ASSERT(tag);

  if (!(rv = krb5_rd_error(ctx, msg, &error)))

  {

    WLog_ERR(tag, "KRB_ERROR: %s", error->text.data);

    krb5_free_error(ctx, error);

  }

  return rv;

}

BOOL krb5glue_authenticator_validate_chksum(krb5glue_authenticator authenticator, int cksumtype,

                                            uint32_t* flags)

{

  WINPR_ASSERT(flags);

  if (!authenticator || !authenticator->checksum ||

      authenticator->checksum->checksum_type != cksumtype || authenticator->checksum->length < 24)

    return FALSE;

  Data_Read_UINT32((authenticator->checksum->contents + 20), (*flags));

  return TRUE;

}

krb5_error_code krb5glue_get_init_creds(krb5_context ctx, krb5_principal princ, krb5_ccache ccache,

                                        krb5_prompter_fct prompter, char* password,

                                        SEC_WINPR_KERBEROS_SETTINGS* krb_settings)

{

  krb5_error_code rv = 0;

  krb5_deltat start_time = 0;

  krb5_get_init_creds_opt* gic_opt = NULL;

  krb5_init_creds_context creds_ctx = NULL;

  char* tmp_profile_path = create_temporary_file();

  profile_t profile = NULL;

  BOOL is_temp_ctx = FALSE;

  WINPR_ASSERT(ctx);

  rv = krb5_get_init_creds_opt_alloc(ctx, &gic_opt);

  if (rv)

    goto cleanup;

  krb5_get_init_creds_opt_set_forwardable(gic_opt, 0);

  krb5_get_init_creds_opt_set_proxiable(gic_opt, 0);

  if (krb_settings)

  {

    if (krb_settings->startTime)

      start_time = krb_settings->startTime;

    if (krb_settings->lifeTime)

      krb5_get_init_creds_opt_set_tkt_life(gic_opt, krb_settings->lifeTime);

    if (krb_settings->renewLifeTime)

      krb5_get_init_creds_opt_set_renew_life(gic_opt, krb_settings->renewLifeTime);

    if (krb_settings->withPac)

    {

      rv = krb5_get_init_creds_opt_set_pac_request(ctx, gic_opt, TRUE);

      if (rv)

        goto cleanup;

    }

    if (krb_settings->armorCache)

    {

      rv = krb5_get_init_creds_opt_set_fast_ccache_name(ctx, gic_opt,

                                                        krb_settings->armorCache);

      if (rv)

        goto cleanup;

    }

    if (krb_settings->pkinitX509Identity)

    {

      rv = krb5_get_init_creds_opt_set_pa(ctx, gic_opt, "X509_user_identity",

                                          krb_settings->pkinitX509Identity);

      if (rv)

        goto cleanup;

    }

    if (krb_settings->pkinitX509Anchors)

    {

      rv = krb5_get_init_creds_opt_set_pa(ctx, gic_opt, "X509_anchors",

                                          krb_settings->pkinitX509Anchors);

      if (rv)

        goto cleanup;

    }

    if (krb_settings->kdcUrl && (strnlen(krb_settings->kdcUrl, 2) > 0))

    {

      const char* names[4] = { 0 };

      char* realm = NULL;

      char* kdc_url = NULL;

      size_t size = 0;

      if ((rv = krb5_get_profile(ctx, &profile)))

        goto cleanup;

      rv = ENOMEM;

      if (winpr_asprintf(&kdc_url, &size, "https://%s/KdcProxy", krb_settings->kdcUrl) <= 0)

      {

        free(kdc_url);

        goto cleanup;

      }

      realm = calloc(princ->realm.length + 1, 1);

      if (!realm)

      {

        free(kdc_url);

        goto cleanup;

      }

      CopyMemory(realm, princ->realm.data, princ->realm.length);

      names[0] = "realms";

      names[1] = realm;

      names[2] = "kdc";

      profile_clear_relation(profile, names);

      profile_add_relation(profile, names, kdc_url);

      /* Since we know who the KDC is, tell krb5 that its certificate is valid for pkinit */

      names[2] = "pkinit_kdc_hostname";

      profile_add_relation(profile, names, krb_settings->kdcUrl);

      free(kdc_url);

      free(realm);

      if ((rv = profile_flush_to_file(profile, tmp_profile_path)))

        goto cleanup;

      profile_abandon(profile);

      profile = NULL;

      if ((rv = profile_init_path(tmp_profile_path, &profile)))

        goto cleanup;

      if ((rv = krb5_init_context_profile(profile, 0, &ctx)))

        goto cleanup;

      is_temp_ctx = TRUE;

    }

  }

  if ((rv = krb5_get_init_creds_opt_set_in_ccache(ctx, gic_opt, ccache)))

    goto cleanup;

  if ((rv = krb5_get_init_creds_opt_set_out_ccache(ctx, gic_opt, ccache)))

    goto cleanup;

  if ((rv =

           krb5_init_creds_init(ctx, princ, prompter, password, start_time, gic_opt, &creds_ctx)))

    goto cleanup;

  if ((rv = krb5_init_creds_get(ctx, creds_ctx)))

    goto cleanup;

cleanup:

  krb5_init_creds_free(ctx, creds_ctx);

  krb5_get_init_creds_opt_free(ctx, gic_opt);

  if (is_temp_ctx)

    krb5_free_context(ctx);

  profile_abandon(profile);

  winpr_DeleteFile(tmp_profile_path);

  free(tmp_profile_path);

  return rv;

}