source4/dsdb/samdb/ldb_modules/acl_util.c

   1 /*
   2   ACL utility functions
   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: acl_util
  22  *
  23  *  Component: ldb ACL modules
  24  *
  25  *  Description: Some auxiliary functions used for access checking
  26  *
  27  *  Author: Nadezhda Ivanova
  28  */
  29 #include "includes.h"
  30 #include "ldb_module.h"
  31 #include "auth/auth.h"
  32 #include "libcli/security/security.h"
  33 #include "dsdb/samdb/samdb.h"
  34 #include "librpc/gen_ndr/ndr_security.h"
  35 #include "param/param.h"
  36 #include "dsdb/samdb/ldb_modules/util.h"
  37
  38 struct security_token *acl_user_token(struct ldb_module *module)
  39 {
  40         struct ldb_context *ldb = ldb_module_get_ctx(module);
  41         struct auth_session_info *session_info
  42                 = (struct auth_session_info *)ldb_get_opaque(ldb, "sessionInfo");
  43         if(!session_info) {
  44                 return NULL;
  45         }
  46         return session_info->security_token;
  47 }
  48
  49 /* performs an access check from inside the module stack
  50  * given the dn of the object to be checked, the required access
  51  * guid is either the guid of the extended right, or NULL
  52  */
  53
  54 int dsdb_module_check_access_on_dn(struct ldb_module *module,
  55                                    TALLOC_CTX *mem_ctx,
  56                                    struct ldb_dn *dn,
  57                                    uint32_t access_mask,
  58                                    const struct GUID *guid,
  59                                    struct ldb_request *parent)
  60 {
  61         int ret;
  62         struct ldb_result *acl_res;
  63         static const char *acl_attrs[] = {
  64                 "nTSecurityDescriptor",
  65                 "objectSid",
  66                 NULL
  67         };
  68         struct ldb_context *ldb = ldb_module_get_ctx(module);
  69         struct auth_session_info *session_info
  70                 = (struct auth_session_info *)ldb_get_opaque(ldb, "sessionInfo");
  71         if(!session_info) {
  72                 return ldb_operr(ldb);
  73         }
  74         ret = dsdb_module_search_dn(module, mem_ctx, &acl_res, dn,
  75                                     acl_attrs,
  76                                     DSDB_FLAG_NEXT_MODULE |
  77                                     DSDB_FLAG_AS_SYSTEM |
  78                                     DSDB_SEARCH_SHOW_RECYCLED,
  79                                     parent);
  80         if (ret != LDB_SUCCESS) {
  81                 ldb_asprintf_errstring(ldb_module_get_ctx(module),
  82                                        "access_check: failed to find object %s\n",
  83                                        ldb_dn_get_linearized(dn));
  84                 return ret;
  85         }
  86         return dsdb_check_access_on_dn_internal(ldb, acl_res,
  87                                                 mem_ctx,
  88                                                 session_info->security_token,
  89                                                 dn,
  90                                                 access_mask,
  91                                                 guid);
  92 }
  93
  94 int acl_check_access_on_attribute(struct ldb_module *module,
  95                                   TALLOC_CTX *mem_ctx,
  96                                   struct security_descriptor *sd,
  97                                   struct dom_sid *rp_sid,
  98                                   uint32_t access_mask,
  99                                   const struct dsdb_attribute *attr)
 100 {
 101         int ret;
 102         NTSTATUS status;
 103         uint32_t access_granted;
 104         struct object_tree *root = NULL;
 105         struct object_tree *new_node = NULL;
 106         TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
 107         struct security_token *token = acl_user_token(module);
 108         if (attr) {
 109                 if (!GUID_all_zero(&attr->attributeSecurityGUID)) {
 110                         if (!insert_in_object_tree(tmp_ctx,
 111                                                    &attr->attributeSecurityGUID,
 112                                                    access_mask, &root,
 113                                                    &new_node)) {
 114                                 DEBUG(10, ("acl_search: cannot add to object tree securityGUID\n"));
 115                                 goto fail;
 116                         }
 117
 118                         if (!insert_in_object_tree(tmp_ctx,
 119                                                    &attr->schemaIDGUID,
 120                                                    access_mask, &new_node,
 121                                                    &new_node)) {
 122                                 DEBUG(10, ("acl_search: cannot add to object tree attributeGUID\n"));
 123                                 goto fail;
 124                         }
 125                 }
 126                 else {
 127                         if (!insert_in_object_tree(tmp_ctx,
 128                                                    &attr->schemaIDGUID,
 129                                                    access_mask, &root,
 130                                                    &new_node)) {
 131                                 DEBUG(10, ("acl_search: cannot add to object tree attributeGUID\n"));
 132                                 goto fail;
 133                         }
 134                 }
 135         }
 136         status = sec_access_check_ds(sd, token,
 137                                      access_mask,
 138                                      &access_granted,
 139                                      root,
 140                                      rp_sid);
 141         if (!NT_STATUS_IS_OK(status)) {
 142                 ret = LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS;
 143         }
 144         else {
 145                 ret = LDB_SUCCESS;
 146         }
 147         talloc_free(tmp_ctx);
 148         return ret;
 149 fail:
 150         talloc_free(tmp_ctx);
 151         return ldb_operr(ldb_module_get_ctx(module));
 152 }
 153
 154
 155 /* checks for validated writes */
 156 int acl_check_extended_right(TALLOC_CTX *mem_ctx,
 157                              struct security_descriptor *sd,
 158                              struct security_token *token,
 159                              const char *ext_right,
 160                              uint32_t right_type,
 161                              struct dom_sid *sid)
 162 {
 163         struct GUID right;
 164         NTSTATUS status;
 165         uint32_t access_granted;
 166         struct object_tree *root = NULL;
 167         struct object_tree *new_node = NULL;
 168         TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
 169
 170         GUID_from_string(ext_right, &right);
 171
 172         if (!insert_in_object_tree(tmp_ctx, &right, right_type,
 173                                    &root, &new_node)) {
 174                 DEBUG(10, ("acl_ext_right: cannot add to object tree\n"));
 175                 talloc_free(tmp_ctx);
 176                 return LDB_ERR_OPERATIONS_ERROR;
 177         }
 178         status = sec_access_check_ds(sd, token,
 179                                      right_type,
 180                                      &access_granted,
 181                                      root,
 182                                      sid);
 183
 184         if (!NT_STATUS_IS_OK(status)) {
 185                 talloc_free(tmp_ctx);
 186                 return LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS;
 187         }
 188         talloc_free(tmp_ctx);
 189         return LDB_SUCCESS;
 190 }
 191
 192 const char *acl_user_name(TALLOC_CTX *mem_ctx, struct ldb_module *module)
 193 {
 194         struct ldb_context *ldb = ldb_module_get_ctx(module);
 195         struct auth_session_info *session_info
 196                 = (struct auth_session_info *)ldb_get_opaque(ldb, "sessionInfo");
 197         if (!session_info) {
 198                 return "UNKNOWN (NULL)";
 199         }
 200
 201         return talloc_asprintf(mem_ctx, "%s\\%s",
 202                                session_info->info->domain_name,
 203                                session_info->info->account_name);
 204 }
 205
 206 uint32_t dsdb_request_sd_flags(struct ldb_request *req, bool *explicit)
 207 {
 208         struct ldb_control *sd_control;
 209         uint32_t sd_flags = 0;
 210
 211         if (explicit) {
 212                 *explicit = false;
 213         }
 214
 215         sd_control = ldb_request_get_control(req, LDB_CONTROL_SD_FLAGS_OID);
 216         if (sd_control) {
 217                 struct ldb_sd_flags_control *sdctr = (struct ldb_sd_flags_control *)sd_control->data;
 218
 219                 sd_flags = sdctr->secinfo_flags;
 220
 221                 if (explicit) {
 222                         *explicit = true;
 223                 }
 224
 225                 /* mark it as handled */
 226                 sd_control->critical = 0;
 227         }
 228
 229         /* we only care for the last 4 bits */
 230         sd_flags &= 0x0000000F;
 231
 232         /*
 233          * MS-ADTS 3.1.1.3.4.1.11 says that no bits
 234          * equals all 4 bits
 235          */
 236         if (sd_flags == 0) {
 237                 sd_flags = 0xF;
 238         }
 239
 240         return sd_flags;
 241 }