source4/dsdb/samdb/ldb_modules/managed_pwd.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    msDS-ManagedPassword attribute for Group Managed Service Accounts
   4
   5    Copyright (C) Catalyst.Net Ltd 2024
   6
   7    This program is free software: you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation, either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <https://www.gnu.org/licenses/>.
  19 */
  20
  21 #include "includes.h"
  22 #include <talloc.h>
  23 #include <ldb.h>
  24 #include <ldb_module.h>
  25 #include <ldb_errors.h>
  26 #include <ldb_private.h>
  27 #include "lib/crypto/gmsa.h"
  28 #include "lib/util/time.h"
  29 #include "librpc/gen_ndr/ndr_gkdi.h"
  30 #include "librpc/gen_ndr/ndr_gmsa.h"
  31 #include "dsdb/gmsa/util.h"
  32 #include "dsdb/samdb/ldb_modules/managed_pwd.h"
  33 #include "dsdb/samdb/ldb_modules/util.h"
  34 #include "dsdb/samdb/samdb.h"
  35
  36 #undef strcasecmp
  37
  38 static int gmsa_managed_password(struct ldb_context *const ldb,
  39                                  struct ldb_message *msg,
  40                                  struct ldb_request *req,
  41                                  struct ldb_reply *ares)
  42 {
  43         TALLOC_CTX *tmp_ctx = NULL;
  44         const struct dsdb_encrypted_connection_state *conn_state = NULL;
  45         int ret = LDB_SUCCESS;
  46         NTSTATUS status = NT_STATUS_OK;
  47         NTTIME current_time;
  48         struct gmsa_update *gmsa_update = NULL;
  49         struct gmsa_return_pwd return_pwd;
  50         bool ok;
  51
  52         /*
  53          * Prevent viewing msDS-ManagedPassword over an insecure connection. The
  54          * opaque is added in the ldap backend init.
  55          */
  56         conn_state = ldb_get_opaque(
  57                 ldb, DSDB_OPAQUE_ENCRYPTED_CONNECTION_STATE_NAME);
  58         if (conn_state != NULL && !conn_state->using_encrypted_connection) {
  59                 ret = dsdb_werror(ldb,
  60                                   LDB_ERR_OPERATIONS_ERROR,
  61                                   WERR_DS_CONFIDENTIALITY_REQUIRED,
  62                                   "Viewing msDS-ManagedPassword requires an "
  63                                   "encrypted connection");
  64                 goto out;
  65         }
  66
  67         {
  68                 /* Is the account a Group Managed Service Account? */
  69                 const bool is_gmsa = dsdb_account_is_gmsa(ldb, msg);
  70                 if (!is_gmsa) {
  71                         /* It’s not a GMSA — we’re done here. */
  72                         ret = LDB_SUCCESS;
  73                         goto out;
  74                 }
  75         }
  76
  77         {
  78                 bool am_rodc = true;
  79
  80                 /* Are we operating as an RODC? */
  81                 ret = samdb_rodc(ldb, &am_rodc);
  82                 if (ret != LDB_SUCCESS) {
  83                         DBG_WARNING("unable to tell if we are an RODC\n");
  84                         goto out;
  85                 }
  86
  87                 if (am_rodc) {
  88                         /* TODO: forward the request to a writable DC. */
  89                         ret = ldb_error(
  90                                 ldb,
  91                                 LDB_ERR_OPERATIONS_ERROR,
  92                                 "msDS-ManagedPassword may only be viewed on a "
  93                                 "writeable DC, not an RODC");
  94                         goto out;
  95                 }
  96         }
  97
  98         tmp_ctx = talloc_new(msg);
  99         if (tmp_ctx == NULL) {
 100                 ret = ldb_oom(ldb);
 101                 goto out;
 102         }
 103
 104         {
 105                 struct dom_sid account_sid;
 106                 bool allowed_to_view = false;
 107
 108                 ret = samdb_result_dom_sid_buf(msg, "objectSid", &account_sid);
 109                 if (ret) {
 110                         goto out;
 111                 }
 112
 113                 ret = gmsa_allowed_to_view_managed_password(
 114                         tmp_ctx, ldb, msg, &account_sid, &allowed_to_view);
 115                 if (ret) {
 116                         goto out;
 117                 }
 118
 119                 if (!allowed_to_view) {
 120                         /* Sorry, you can’t view the password. */
 121                         goto out;
 122                 }
 123         }
 124
 125         ok = dsdb_gmsa_current_time(ldb, &current_time);
 126         if (!ok) {
 127                 ret = ldb_operr(ldb);
 128                 goto out;
 129         }
 130
 131         ret = gmsa_recalculate_managed_pwd(
 132                 tmp_ctx, ldb, msg, current_time, &gmsa_update, &return_pwd);
 133         if (ret) {
 134                 goto out;
 135         }
 136
 137         SMB_ASSERT(return_pwd.new_pwd != NULL);
 138
 139         {
 140                 DATA_BLOB packed_blob = {};
 141
 142                 status = gmsa_pack_managed_pwd(
 143                         tmp_ctx,
 144                         return_pwd.new_pwd->buf,
 145                         return_pwd.prev_pwd != NULL ? return_pwd.prev_pwd->buf
 146                                                     : NULL,
 147                         return_pwd.query_interval,
 148                         return_pwd.unchanged_interval,
 149                         &packed_blob);
 150                 if (!NT_STATUS_IS_OK(status)) {
 151                         ret = ldb_operr(ldb);
 152                         goto out;
 153                 }
 154
 155                 ret = ldb_msg_add_steal_value(msg,
 156                                               "msDS-ManagedPassword",
 157                                               &packed_blob);
 158                 if (ret) {
 159                         goto out;
 160                 }
 161         }
 162
 163 out:
 164         TALLOC_FREE(tmp_ctx);
 165         return ret;
 166 }
 167
 168 int constructed_msds_managed_password(struct ldb_module *module,
 169                                       struct ldb_message *msg,
 170                                       enum ldb_scope scope,
 171                                       struct ldb_request *parent,
 172                                       struct ldb_reply *ares)
 173 {
 174         return gmsa_managed_password(ldb_module_get_ctx(module),
 175                                      msg,
 176                                      parent,
 177                                      ares);
 178 }