/*

   Unix SMB/CIFS implementation.

   User credentials handling (as regards on-disk files)

   Copyright (C) Jelmer Vernooij 2005

   Copyright (C) Tim Potter 2001

   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2005

   This program is free software; you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 3 of the License, or

   (at your option) any later version.

   This program is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with this program.  If not, see <http://www.gnu.org/licenses/>.

*/

#include "includes.h"

#include "lib/events/events.h"

#include <ldb.h>

#include "librpc/gen_ndr/samr.h" /* for struct samrPassword */

#include "param/secrets.h"

#include "system/filesys.h"

#include "auth/credentials/credentials.h"

#include "auth/credentials/credentials_internal.h"

#include "auth/credentials/credentials_krb5.h"

#include "auth/kerberos/kerberos_util.h"

#include "param/param.h"

#include "lib/events/events.h"

#include "dsdb/samdb/samdb.h"

#include "source3/include/secrets.h"

#include "dbwrap/dbwrap.h"

#include "dbwrap/dbwrap_open.h"

#include "lib/util/util_tdb.h"

#include "libds/common/roles.h"

#undef DBGC_CLASS

#define DBGC_CLASS DBGC_AUTH

/**

 * Fill in credentials for the machine trust account, from the secrets database.

 *

 * @param cred Credentials structure to fill in

 * @retval NTSTATUS error detailing any failure

 */

static NTSTATUS cli_credentials_set_secrets_lct(struct cli_credentials *cred,

            struct loadparm_context *lp_ctx,

            struct ldb_context *ldb,

            const char *base,

            const char *filter,

            time_t secrets_tdb_last_change_time,

            const char *secrets_tdb_password,

            char **error_string)

{

  TALLOC_CTX *mem_ctx;

  int ldb_ret;

  struct ldb_message *msg;

  const char *machine_account;

  const char *password;

  const char *domain;

  const char *realm;

  enum netr_SchannelType sct;

  const char *salt_principal;

  char *keytab;

  const struct ldb_val *whenChanged;

  time_t lct;

  /* ok, we are going to get it now, don't recurse back here */

  cred->machine_account_pending = false;

  /* some other parts of the system will key off this */

  cred->machine_account = true;

  mem_ctx = talloc_named(cred, 0, "cli_credentials_set_secrets from ldb");

  if (!ldb) {

    /* Local secrets are stored in secrets.ldb */

    ldb = secrets_db_connect(mem_ctx, lp_ctx);

    if (!ldb) {

      *error_string = talloc_strdup(cred, "Could not open secrets.ldb");

      talloc_free(mem_ctx);

      return NT_STATUS_CANT_ACCESS_DOMAIN_INFO;

    }

  }

  ldb_ret = dsdb_search_one(ldb, mem_ctx, &msg,

          ldb_dn_new(mem_ctx, ldb, base),

          LDB_SCOPE_SUBTREE,

          NULL, 0, "%s", filter);

  if (ldb_ret != LDB_SUCCESS) {

    *error_string = talloc_asprintf(cred, "Could not find entry to match filter: '%s' base: '%s': %s: %s",

            filter, base ? base : "",

            ldb_strerror(ldb_ret), ldb_errstring(ldb));

    talloc_free(mem_ctx);

    return NT_STATUS_CANT_ACCESS_DOMAIN_INFO;

  }

  password = ldb_msg_find_attr_as_string(msg, "secret", NULL);

  whenChanged = ldb_msg_find_ldb_val(msg, "whenChanged");

  if (!whenChanged || ldb_val_to_time(whenChanged, &lct) != LDB_SUCCESS) {

    /* This attribute is mandatory */

    talloc_free(mem_ctx);

    return NT_STATUS_NOT_FOUND;

  }

  /* Don't set secrets.ldb info if the secrets.tdb entry was more recent */

  if (lct < secrets_tdb_last_change_time) {

    talloc_free(mem_ctx);

    return NT_STATUS_NOT_FOUND;

  }

  if ((lct == secrets_tdb_last_change_time) &&

      (secrets_tdb_password != NULL) &&

      (password != NULL) &&

      (strcmp(password, secrets_tdb_password) != 0)) {

    talloc_free(mem_ctx);

    return NT_STATUS_NOT_FOUND;

  }

  cli_credentials_set_password_last_changed_time(cred, lct);

  machine_account = ldb_msg_find_attr_as_string(msg, "sAMAccountName", NULL);

  if (!machine_account) {

    machine_account = ldb_msg_find_attr_as_string(msg, "servicePrincipalName", NULL);

    if (!machine_account) {

      const char *ldap_bind_dn = ldb_msg_find_attr_as_string(msg, "ldapBindDn", NULL);

      if (!ldap_bind_dn) {

        *error_string = talloc_asprintf(cred,

                "Could not find 'samAccountName', "

                "'servicePrincipalName' or "

                "'ldapBindDn' in secrets record: %s",

                ldb_dn_get_linearized(msg->dn));

        talloc_free(mem_ctx);

        return NT_STATUS_CANT_ACCESS_DOMAIN_INFO;

      } else {

        /* store bind dn in credentials */

        cli_credentials_set_bind_dn(cred, ldap_bind_dn);

      }

    }

  }

  salt_principal = ldb_msg_find_attr_as_string(msg, "saltPrincipal", NULL);

  cli_credentials_set_salt_principal(cred, salt_principal);

  sct = ldb_msg_find_attr_as_int(msg, "secureChannelType", 0);

  if (sct) {

    cli_credentials_set_secure_channel_type(cred, sct);

  }

  if (!password) {

    const struct ldb_val *nt_password_hash = ldb_msg_find_ldb_val(msg, "unicodePwd");

    struct samr_Password hash;

    ZERO_STRUCT(hash);

    if (nt_password_hash) {

      memcpy(hash.hash, nt_password_hash->data,

             MIN(nt_password_hash->length, sizeof(hash.hash)));

      cli_credentials_set_nt_hash(cred, &hash, CRED_SPECIFIED);

    } else {

      cli_credentials_set_password(cred, NULL, CRED_SPECIFIED);

    }

  } else {

    cli_credentials_set_password(cred, password, CRED_SPECIFIED);

  }

  domain = ldb_msg_find_attr_as_string(msg, "flatname", NULL);

  if (domain) {

    cli_credentials_set_domain(cred, domain, CRED_SPECIFIED);

  }

  realm = ldb_msg_find_attr_as_string(msg, "realm", NULL);

  if (realm) {

    cli_credentials_set_realm(cred, realm, CRED_SPECIFIED);

  }

  if (machine_account) {

    cli_credentials_set_username(cred, machine_account, CRED_SPECIFIED);

  }

  cli_credentials_set_kvno(cred, ldb_msg_find_attr_as_int(msg, "msDS-KeyVersionNumber", 0));

  /* If there was an external keytab specified by reference in

   * the LDB, then use this.  Otherwise we will make one up

   * (chewing CPU time) from the password */

  keytab = keytab_name_from_msg(cred, ldb, msg);

  if (keytab) {

    cli_credentials_set_keytab_name(cred, lp_ctx, keytab, CRED_SPECIFIED);

    talloc_free(keytab);

  }

  talloc_free(mem_ctx);

  return NT_STATUS_OK;

}

/**

 * Fill in credentials for the machine trust account, from the secrets database.

 *

 * @param cred Credentials structure to fill in

 * @retval NTSTATUS error detailing any failure

 */

_PUBLIC_ NTSTATUS cli_credentials_set_secrets(struct cli_credentials *cred,

                struct loadparm_context *lp_ctx,

                struct ldb_context *ldb,

                const char *base,

                const char *filter,

                char **error_string)

{

  NTSTATUS status = cli_credentials_set_secrets_lct(cred, lp_ctx, ldb, base, filter, 0, NULL, error_string);

  if (!NT_STATUS_IS_OK(status)) {

    /* set anonymous as the fallback, if the machine account won't work */

    cli_credentials_set_anonymous(cred);

  }

  return status;

}

/**

 * Fill in credentials for the machine trust account, from the secrets database.

 *

 * @param cred Credentials structure to fill in

 * @retval NTSTATUS error detailing any failure

 */

_PUBLIC_ NTSTATUS cli_credentials_set_machine_account(struct cli_credentials *cred,

                  struct loadparm_context *lp_ctx)

{

  struct db_context *db_ctx;

  char *secrets_tdb_path;

  int hash_size, tdb_flags;

  secrets_tdb_path = lpcfg_private_db_path(cred, lp_ctx, "secrets");

  if (secrets_tdb_path == NULL) {

    return NT_STATUS_NO_MEMORY;

  }

  hash_size = lpcfg_tdb_hash_size(lp_ctx, secrets_tdb_path);

  tdb_flags = lpcfg_tdb_flags(lp_ctx, TDB_DEFAULT);

  db_ctx = dbwrap_local_open(

    cred,

    secrets_tdb_path,

    hash_size,

    tdb_flags,

    O_RDWR,

    0600,

    DBWRAP_LOCK_ORDER_1,

    DBWRAP_FLAG_NONE);

  TALLOC_FREE(secrets_tdb_path);

  /*

   * We do not check for errors here, we might not have a

   * secrets.tdb at all, and so we just need to check the

   * secrets.ldb

   */

  return cli_credentials_set_machine_account_db_ctx(cred, lp_ctx, db_ctx);

}

/**

 * Fill in credentials for the machine trust account, from the

 * secrets.ldb or passed in handle to secrets.tdb (perhaps in CTDB).

 *

 * This version is used in parts of the code that can link in the

 * CTDB dbwrap backend, by passing down the already open handle.

 *

 * @param cred Credentials structure to fill in

 * @param db_ctx dbwrap context for secrets.tdb

 * @retval NTSTATUS error detailing any failure

 */

_PUBLIC_ NTSTATUS cli_credentials_set_machine_account_db_ctx(struct cli_credentials *cred,

                   struct loadparm_context *lp_ctx,

                   struct db_context *db_ctx)

{

  NTSTATUS status;

  char *filter;

  char *error_string = NULL;

  const char *domain;

  bool secrets_tdb_password_more_recent;

  time_t secrets_tdb_lct = 0;

  char *secrets_tdb_password = NULL;

  char *secrets_tdb_old_password = NULL;

  uint32_t secrets_tdb_secure_channel_type = SEC_CHAN_NULL;

  int server_role = lpcfg_server_role(lp_ctx);

  int security = lpcfg_security(lp_ctx);

  char *keystr;

  char *keystr_upper = NULL;

  TALLOC_CTX *tmp_ctx = talloc_named(cred, 0, "cli_credentials_set_secrets from ldb");

  if (!tmp_ctx) {

    return NT_STATUS_NO_MEMORY;

  }

  /* Bleh, nasty recursion issues: We are setting a machine

   * account here, so we don't want the 'pending' flag around

   * any more */

  cred->machine_account_pending = false;

  /* We have to do this, as the fallback in

   * cli_credentials_set_secrets is to run as anonymous, so the domain is wiped */

  domain = cli_credentials_get_domain(cred);

  if (db_ctx) {

    TDB_DATA dbuf;

    keystr = talloc_asprintf(tmp_ctx, "%s/%s",

           SECRETS_MACHINE_LAST_CHANGE_TIME,

           domain);

    keystr_upper = strupper_talloc(tmp_ctx, keystr);

    status = dbwrap_fetch(db_ctx, tmp_ctx, string_tdb_data(keystr_upper),

              &dbuf);

    if (NT_STATUS_IS_OK(status) && dbuf.dsize == 4) {

      secrets_tdb_lct = IVAL(dbuf.dptr,0);

    }

    keystr = talloc_asprintf(tmp_ctx, "%s/%s",

           SECRETS_MACHINE_PASSWORD,

           domain);

    keystr_upper = strupper_talloc(tmp_ctx, keystr);

    status = dbwrap_fetch(db_ctx, tmp_ctx, string_tdb_data(keystr_upper),

              &dbuf);

    if (NT_STATUS_IS_OK(status)) {

      secrets_tdb_password = (char *)dbuf.dptr;

    }

    keystr = talloc_asprintf(tmp_ctx, "%s/%s",

           SECRETS_MACHINE_PASSWORD_PREV,

           domain);

    keystr_upper = strupper_talloc(tmp_ctx, keystr);

    status = dbwrap_fetch(db_ctx, tmp_ctx, string_tdb_data(keystr_upper),

              &dbuf);

    if (NT_STATUS_IS_OK(status)) {

      secrets_tdb_old_password = (char *)dbuf.dptr;

    }

    keystr = talloc_asprintf(tmp_ctx, "%s/%s",

           SECRETS_MACHINE_SEC_CHANNEL_TYPE,

           domain);

    keystr_upper = strupper_talloc(tmp_ctx, keystr);

    status = dbwrap_fetch(db_ctx, tmp_ctx, string_tdb_data(keystr_upper),

              &dbuf);

    if (NT_STATUS_IS_OK(status) && dbuf.dsize == 4) {

      secrets_tdb_secure_channel_type = IVAL(dbuf.dptr,0);

    }

  }

  filter = talloc_asprintf(cred, SECRETS_PRIMARY_DOMAIN_FILTER, 

         domain);

  status = cli_credentials_set_secrets_lct(cred, lp_ctx, NULL,

             SECRETS_PRIMARY_DOMAIN_DN,

             filter, secrets_tdb_lct, secrets_tdb_password, &error_string);

  if (secrets_tdb_password == NULL) {

    secrets_tdb_password_more_recent = false;

  } else if (NT_STATUS_EQUAL(NT_STATUS_CANT_ACCESS_DOMAIN_INFO, status)

      || NT_STATUS_EQUAL(NT_STATUS_NOT_FOUND, status)) {

    secrets_tdb_password_more_recent = true;

  } else if (secrets_tdb_lct > cli_credentials_get_password_last_changed_time(cred)) {

    secrets_tdb_password_more_recent = true;

  } else if (secrets_tdb_lct == cli_credentials_get_password_last_changed_time(cred)) {

    secrets_tdb_password_more_recent = strcmp(secrets_tdb_password, cli_credentials_get_password(cred)) != 0;

  } else {

    secrets_tdb_password_more_recent = false;

  }

  if (secrets_tdb_password_more_recent) {

    char *machine_account = talloc_asprintf(tmp_ctx, "%s$", lpcfg_netbios_name(lp_ctx));

    cli_credentials_set_password(cred, secrets_tdb_password, CRED_SPECIFIED);

    cli_credentials_set_old_password(cred, secrets_tdb_old_password, CRED_SPECIFIED);

    cli_credentials_set_domain(cred, domain, CRED_SPECIFIED);

    if (strequal(domain, lpcfg_workgroup(lp_ctx))) {

      enum credentials_use_kerberos use_kerberos =

        cli_credentials_get_kerberos_state(cred);

      enum credentials_obtained use_kerberos_obtained =

        cli_credentials_get_kerberos_state_obtained(cred);

      bool is_ad = false;

      cli_credentials_set_realm(cred, lpcfg_realm(lp_ctx), CRED_SPECIFIED);

      switch (server_role) {

      case ROLE_DOMAIN_MEMBER:

        if (security != SEC_ADS) {

          break;

        }

        FALL_THROUGH;

      case ROLE_ACTIVE_DIRECTORY_DC:

      case ROLE_IPA_DC:

        is_ad = true;

        break;

      }

      if (use_kerberos != CRED_USE_KERBEROS_DESIRED || is_ad) {

        /*

         * Keep an explicit selection

         *

         * For AD domains we also keep

         * CRED_USE_KERBEROS_DESIRED

         */

      } else if (use_kerberos_obtained <= CRED_SMB_CONF) {

        /*

         * Disable kerberos by default within

         * an NT4 domain.

         */

        cli_credentials_set_kerberos_state(cred,

            CRED_USE_KERBEROS_DISABLED,

            CRED_SMB_CONF);

      }

    }

    cli_credentials_set_username(cred, machine_account, CRED_SPECIFIED);

    cli_credentials_set_password_last_changed_time(cred, secrets_tdb_lct);

    cli_credentials_set_secure_channel_type(cred, secrets_tdb_secure_channel_type);

    status = NT_STATUS_OK;

  } else if (!NT_STATUS_IS_OK(status)) {

    if (db_ctx) {

      error_string

        = talloc_asprintf(cred,

              "Failed to fetch machine account password for %s from both "

              "secrets.ldb (%s) and from %s",

              domain,

              error_string == NULL ? "error" : error_string,

              dbwrap_name(db_ctx));

    } else {

      char *secrets_tdb_path;

      secrets_tdb_path = lpcfg_private_db_path(tmp_ctx,

                 lp_ctx,

                 "secrets");

      if (secrets_tdb_path == NULL) {

        return NT_STATUS_NO_MEMORY;

      }

      error_string = talloc_asprintf(cred,

                   "Failed to fetch machine account password from "

                   "secrets.ldb: %s and failed to open %s",

                   error_string == NULL ? "error" : error_string,

                   secrets_tdb_path);

    }

    DEBUG(1, ("Could not find machine account in secrets database: %s: %s\n",

        error_string == NULL ? "error" : error_string,

        nt_errstr(status)));

    /* set anonymous as the fallback, if the machine account won't work */

    cli_credentials_set_anonymous(cred);

  }

  TALLOC_FREE(tmp_ctx);

  return status;

}

/**

 * Fill in credentials for a particular principal, from the secrets database.

 *

 * @param cred Credentials structure to fill in

 * @retval NTSTATUS error detailing any failure

 */

_PUBLIC_ NTSTATUS cli_credentials_set_stored_principal(struct cli_credentials *cred,

                struct loadparm_context *lp_ctx,

                const char *serviceprincipal)

{

  NTSTATUS status;

  char *filter;

  char *error_string = NULL;

  /* Bleh, nasty recursion issues: We are setting a machine

   * account here, so we don't want the 'pending' flag around

   * any more */

  cred->machine_account_pending = false;

  filter = talloc_asprintf(cred, SECRETS_PRINCIPAL_SEARCH,

         cli_credentials_get_realm(cred),

         cli_credentials_get_domain(cred),

         serviceprincipal);

  status = cli_credentials_set_secrets_lct(cred, lp_ctx, NULL,

               SECRETS_PRINCIPALS_DN, filter,

               0, NULL, &error_string);

  if (!NT_STATUS_IS_OK(status)) {

    DEBUG(1, ("Could not find %s principal in secrets database: %s: %s\n",

        serviceprincipal, nt_errstr(status),

        error_string ? error_string : "<no error>"));

  }

  return status;

}

/**

 * Ask that when required, the credentials system will be filled with

 * machine trust account, from the secrets database.

 *

 * @param cred Credentials structure to fill in

 * @note This function is used to call the above function after, rather

 *       than during, popt processing.

 *

 */

_PUBLIC_ void cli_credentials_set_machine_account_pending(struct cli_credentials *cred,

             struct loadparm_context *lp_ctx)

{

  cred->machine_account_pending = true;

  cred->machine_account_pending_lp_ctx = lp_ctx;

}