libcli/security/object_tree.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    security access checking routines
   5
   6    Copyright (C) Nadezhda Ivanova 2009
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 /*
  23  *  Description: Contains data handler functions for
  24  *               the object tree that must be constructed to perform access checks.
  25  *               The object tree is an unbalanced tree of depth 3, indexed by
  26  *               object type guid. Perhaps a different data structure
  27  *               should be concidered later to improve performance
  28  *
  29  *  Author: Nadezhda Ivanova
  30  */
  31 #include "includes.h"
  32 #include "libcli/security/security.h"
  33 #include "librpc/ndr/libndr.h"
  34
  35 /* Adds a new node to the object tree. If attributeSecurityGUID is not zero and
  36  * has already been added to the tree, the new node is added as a child of that node
  37  * In all other cases as a child of the root
  38  */
  39
  40 bool insert_in_object_tree(TALLOC_CTX *mem_ctx,
  41                            const struct GUID *guid,
  42                            uint32_t init_access,
  43                            struct object_tree *root,
  44                            struct object_tree **new_node_out)
  45 {
  46         struct object_tree *new_node;
  47
  48         if (!guid || GUID_all_zero(guid)){
  49                 return true;
  50         }
  51
  52         if (!root) {
  53                 root = talloc_zero(mem_ctx, struct object_tree);
  54                 if (!root) {
  55                         return false;
  56                 }
  57                 new_node = root;
  58         } else {
  59                 int i;
  60
  61                 for (i = 0; i < root->num_of_children; i++) {
  62                         if (GUID_equal(&root->children[i].guid, guid)) {
  63                                 new_node = &root->children[i];
  64                                 *new_node_out = new_node;
  65                                 return true;
  66                         }
  67                 }
  68
  69                 root->children = talloc_realloc(mem_ctx, root->children,
  70                                                 struct object_tree,
  71                                                 root->num_of_children + 1);
  72                 if (!root->children) {
  73                         return false;
  74                 }
  75                 new_node = &root->children[root->num_of_children];
  76                 root->num_of_children++;
  77         }
  78
  79         new_node->children = NULL;
  80         new_node->guid = *guid;
  81         new_node->remaining_access = init_access;
  82         new_node->num_of_children = 0;
  83
  84         *new_node_out = new_node;
  85         return true;
  86 }
  87
  88 /* search by GUID */
  89 struct object_tree *get_object_tree_by_GUID(struct object_tree *root,
  90                                              const struct GUID *guid)
  91 {
  92         struct object_tree *result = NULL;
  93         int i;
  94
  95         if (!root || GUID_equal(&root->guid, guid)) {
  96                 result = root;
  97                 return result;
  98         }
  99         else if (root->num_of_children > 0) {
 100                 for (i = 0; i < root->num_of_children; i++) {
 101                 if ((result = get_object_tree_by_GUID(&root->children[i], guid)))
 102                         break;
 103                 }
 104         }
 105         return result;
 106 }
 107
 108 /* Change the granted access per each ACE */
 109
 110 void object_tree_modify_access(struct object_tree *root,
 111                                uint32_t access_mask)
 112 {
 113         root->remaining_access &= ~access_mask;
 114         if (root->num_of_children > 0) {
 115                 int i;
 116                 for (i = 0; i < root->num_of_children; i++) {
 117                         object_tree_modify_access(&root->children[i], access_mask);
 118                 }
 119         }
 120 }