source4/dsdb/common/dsdb_access.c

   1 /*
   2   ldb database library
   3
   4   Copyright (C) Nadezhda Ivanova 2010
   5
   6   This program is free software; you can redistribute it and/or modify
   7   it under the terms of the GNU General Public License as published by
   8   the Free Software Foundation; either version 3 of the License, or
   9   (at your option) any later version.
  10
  11   This program is distributed in the hope that it will be useful,
  12   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14   GNU General Public License for more details.
  15
  16   You should have received a copy of the GNU General Public License
  17   along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 /*
  21  *  Name: dsdb_access
  22  *
  23  *  Description: utility functions for access checking on objects
  24  *
  25  *  Authors: Nadezhda Ivanova
  26  */
  27
  28 #include "includes.h"
  29 #include "ldb.h"
  30 #include "ldb_module.h"
  31 #include "ldb_errors.h"
  32 #include "libcli/security/security.h"
  33 #include "librpc/gen_ndr/ndr_security.h"
  34 #include "libcli/ldap/ldap_ndr.h"
  35 #include "param/param.h"
  36 #include "auth/auth.h"
  37 #include "dsdb/samdb/samdb.h"
  38
  39 void dsdb_acl_debug(struct security_descriptor *sd,
  40                       struct security_token *token,
  41                       struct ldb_dn *dn,
  42                       bool denied,
  43                       int level)
  44 {
  45         if (denied) {
  46                 DEBUG(level, ("Access on %s denied", ldb_dn_get_linearized(dn)));
  47         } else {
  48                 DEBUG(level, ("Access on %s granted", ldb_dn_get_linearized(dn)));
  49         }
  50
  51         DEBUG(level,("Security context: %s\n",
  52                      ndr_print_struct_string(0,(ndr_print_fn_t)ndr_print_security_token,"", token)));
  53         DEBUG(level,("Security descriptor: %s\n",
  54                      ndr_print_struct_string(0,(ndr_print_fn_t)ndr_print_security_descriptor,"", sd)));
  55 }
  56
  57 int dsdb_get_sd_from_ldb_message(struct ldb_context *ldb,
  58                                  TALLOC_CTX *mem_ctx,
  59                                  struct ldb_message *acl_res,
  60                                  struct security_descriptor **sd)
  61 {
  62         struct ldb_message_element *sd_element;
  63         enum ndr_err_code ndr_err;
  64
  65         sd_element = ldb_msg_find_element(acl_res, "nTSecurityDescriptor");
  66         if (!sd_element) {
  67                 *sd = NULL;
  68                 return LDB_SUCCESS;
  69         }
  70         *sd = talloc(mem_ctx, struct security_descriptor);
  71         if(!*sd) {
  72                 return ldb_oom(ldb);
  73         }
  74         ndr_err = ndr_pull_struct_blob(&sd_element->values[0], *sd, *sd,
  75                                        (ndr_pull_flags_fn_t)ndr_pull_security_descriptor);
  76
  77         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
  78                 return ldb_operr(ldb);
  79         }
  80
  81         return LDB_SUCCESS;
  82 }
  83
  84 int dsdb_check_access_on_dn_internal(struct ldb_context *ldb,
  85                                      struct ldb_result *acl_res,
  86                                      TALLOC_CTX *mem_ctx,
  87                                      struct security_token *token,
  88                                      struct ldb_dn *dn,
  89                                      uint32_t access,
  90                                      const struct GUID *guid)
  91 {
  92         struct security_descriptor *sd = NULL;
  93         struct dom_sid *sid = NULL;
  94         struct object_tree *root = NULL;
  95         struct object_tree *new_node = NULL;
  96         NTSTATUS status;
  97         uint32_t access_granted;
  98         int ret;
  99
 100         ret = dsdb_get_sd_from_ldb_message(ldb, mem_ctx, acl_res->msgs[0], &sd);
 101         if (ret != LDB_SUCCESS) {
 102                 return ldb_operr(ldb);
 103         }
 104         /* Theoretically we pass the check if the object has no sd */
 105         if (!sd) {
 106                 return LDB_SUCCESS;
 107         }
 108         sid = samdb_result_dom_sid(mem_ctx, acl_res->msgs[0], "objectSid");
 109         if (guid) {
 110                 if (!insert_in_object_tree(mem_ctx, guid, access, &root, &new_node)) {
 111                         return ldb_operr(ldb);
 112                 }
 113         }
 114         status = sec_access_check_ds(sd, token,
 115                                      access,
 116                                      &access_granted,
 117                                      root,
 118                                      sid);
 119         if (!NT_STATUS_IS_OK(status)) {
 120                 dsdb_acl_debug(sd,
 121                                token,
 122                                dn,
 123                                true,
 124                                10);
 125                 return LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS;
 126         }
 127         return LDB_SUCCESS;
 128 }
 129
 130 /* performs an access check from outside the module stack
 131  * given the dn of the object to be checked, the required access
 132  * guid is either the guid of the extended right, or NULL
 133  */
 134
 135 int dsdb_check_access_on_dn(struct ldb_context *ldb,
 136                             TALLOC_CTX *mem_ctx,
 137                             struct ldb_dn *dn,
 138                             uint32_t access,
 139                             const struct GUID *guid)
 140 {
 141         int ret;
 142         struct ldb_result *acl_res;
 143         static const char *acl_attrs[] = {
 144                 "nTSecurityDescriptor",
 145                 "objectSid",
 146                 NULL
 147         };
 148
 149         struct auth_session_info *session_info
 150                 = (struct auth_session_info *)ldb_get_opaque(ldb, "sessionInfo");
 151         if(!session_info) {
 152                 return ldb_operr(ldb);
 153         }
 154
 155         ret = ldb_search(ldb, mem_ctx, &acl_res, dn, LDB_SCOPE_BASE, acl_attrs, NULL);
 156         if (ret != LDB_SUCCESS) {
 157                 DEBUG(10,("access_check: failed to find object %s\n", ldb_dn_get_linearized(dn)));
 158                 return ret;
 159         }
 160
 161         return dsdb_check_access_on_dn_internal(ldb, acl_res,
 162                                                 mem_ctx,
 163                                                 session_info->security_token,
 164                                                 dn,
 165                                                 access,
 166                                                 guid);
 167 }
 168