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)
  45 {
  46         if (!guid || GUID_all_zero(guid)){
  47                 return true;
  48         }
  49
  50         if (!*root){
  51                 *root = talloc_zero(mem_ctx, struct object_tree);
  52                 if (!*root) {
  53                         return false;
  54                 }
  55                 (*root)->guid = *guid;
  56                 *new_node = *root;
  57                 return true;
  58         }
  59
  60         if (!(*root)->children) {
  61                 (*root)->children = talloc_array(mem_ctx, struct object_tree, 1);
  62                 (*root)->children[0].guid = *guid;
  63                 (*root)->children[0].num_of_children = 0;
  64                 (*root)->children[0].children = NULL;
  65                 (*root)->num_of_children++;
  66                 (*root)->children[0].remaining_access = init_access;
  67                 *new_node = &((*root)->children[0]);
  68                 return true;
  69         }
  70         else {
  71                 int i;
  72                 for (i = 0; i < (*root)->num_of_children; i++) {
  73                         if (GUID_equal(&((*root)->children[i].guid), guid)) {
  74                                 *new_node = &((*root)->children[i]);
  75                                 return true;
  76                         }
  77                 }
  78                 (*root)->children = talloc_realloc(mem_ctx, (*root)->children, struct object_tree,
  79                                                    (*root)->num_of_children +1);
  80                 (*root)->children[(*root)->num_of_children].guid = *guid;
  81                 (*root)->children[(*root)->num_of_children].remaining_access = init_access;
  82                 *new_node = &((*root)->children[(*root)->num_of_children]);
  83                 (*root)->num_of_children++;
  84                 return true;
  85         }
  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 }