s4-dsdb: relax a bit the checks on read acl when dirsync control is specified
[mat/samba.git] / source4 / dsdb / samdb / ldb_modules / acl_read.c
index 81f9bf62842245f74b4d684cf2ecb125198baa6c..e7c54c970bd0ff9aaa8f1e5e85e7754bb845a7c6 100644 (file)
@@ -44,29 +44,37 @@ struct aclread_context {
        struct ldb_request *req;
        const char * const *attrs;
        const struct dsdb_schema *schema;
+       bool sd;
+       bool instance_type;
+       bool object_sid;
+       bool indirsync;
 };
 
 struct aclread_private {
        bool enabled;
 };
 
+static void aclread_mark_inaccesslible(struct ldb_message_element *el) {
+        el->flags |= LDB_FLAG_INTERNAL_INACCESSIBLE_ATTRIBUTE;
+}
+
+static bool aclread_is_inaccessible(struct ldb_message_element *el) {
+       return el->flags & LDB_FLAG_INTERNAL_INACCESSIBLE_ATTRIBUTE;
+}
+
 static int aclread_callback(struct ldb_request *req, struct ldb_reply *ares)
 {
         struct ldb_context *ldb;
         struct aclread_context *ac;
-        struct ldb_result *acl_res;
-        struct ldb_message_element *parent;
-        static const char *acl_attrs[] = {
-                "nTSecurityDescriptor",
-                "objectSid",
-                "parentGUID",
-                NULL
-        };
-        int ret;
-        unsigned int i;
+        struct ldb_message *ret_msg;
+        struct ldb_message *msg;
+        int ret, num_of_attrs = 0;
+        unsigned int i, k = 0;
         struct security_descriptor *sd;
         struct dom_sid *sid = NULL;
         TALLOC_CTX *tmp_ctx;
+        uint32_t instanceType;
+
         ac = talloc_get_type(req->context, struct aclread_context);
         ldb = ldb_module_get_ctx(ac->module);
         if (!ares) {
@@ -79,100 +87,143 @@ static int aclread_callback(struct ldb_request *req, struct ldb_reply *ares)
         tmp_ctx = talloc_new(ac);
         switch (ares->type) {
         case LDB_REPLY_ENTRY:
-                ret = dsdb_module_search_dn(ac->module, tmp_ctx, &acl_res, ares->message->dn,
-                                            acl_attrs,
-                                            DSDB_FLAG_NEXT_MODULE |
-                                            DSDB_SEARCH_SHOW_DELETED);
-                if (ret != LDB_SUCCESS) {
-                        goto fail;
-                }
-                ret = dsdb_get_sd_from_ldb_message(ldb, tmp_ctx, acl_res->msgs[0], &sd);
-                if (ret != LDB_SUCCESS) {
+                msg = ares->message;
+                ret = dsdb_get_sd_from_ldb_message(ldb, tmp_ctx, msg, &sd);
+                if (ret != LDB_SUCCESS || sd == NULL ) {
                         DEBUG(10, ("acl_read: cannot get descriptor\n"));
                         ret = LDB_ERR_OPERATIONS_ERROR;
                         goto fail;
                 }
-                sid = samdb_result_dom_sid(tmp_ctx, acl_res->msgs[0], "objectSid");
-                /* get the parent guid */
-                parent = ldb_msg_find_element(acl_res->msgs[0], "parentGUID");
-                if (parent) {
-                        /* the object has a parent, so we have to check for visibility */
-                        struct GUID parent_guid = samdb_result_guid(acl_res->msgs[0], "parentGUID");
-                        ret = dsdb_module_check_access_on_guid(ac->module,
-                                                               tmp_ctx,
-                                                               &parent_guid,
-                                                               SEC_ADS_LIST,
-                                                               NULL);
-                        if (ret == LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS) {
-                                talloc_free(tmp_ctx);
-                                return LDB_SUCCESS;
-                        } else if (ret != LDB_SUCCESS) {
-                                goto fail;
-                        }
+                sid = samdb_result_dom_sid(tmp_ctx, msg, "objectSid");
+                /* get the object instance type */
+                instanceType = ldb_msg_find_attr_as_uint(msg,
+                                                        "instanceType", 0);
+                if (!ldb_dn_is_null(msg->dn) && !(instanceType & INSTANCE_TYPE_IS_NC_HEAD))
+                {
+                       /* the object has a parent, so we have to check for visibility */
+                       struct ldb_dn *parent_dn = ldb_dn_get_parent(tmp_ctx, msg->dn);
+                       ret = dsdb_module_check_access_on_dn(ac->module,
+                                                            tmp_ctx,
+                                                            parent_dn,
+                                                            SEC_ADS_LIST,
+                                                            NULL, req);
+                       if (ret == LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS) {
+                               talloc_free(tmp_ctx);
+                               return LDB_SUCCESS;
+                       } else if (ret != LDB_SUCCESS) {
+                               goto fail;
+                       }
                 }
                 /* for every element in the message check RP */
-                i = 0;
-                while (i < ares->message->num_elements) {
-                        char *p, *new_attr;
+                for (i=0; i < msg->num_elements; i++) {
                         const struct dsdb_attribute *attr;
-                        p = strchr(ares->message->elements[i].name, ';');
-                        if (!p) {
-                                attr =  dsdb_attribute_by_lDAPDisplayName(ac->schema,
-                                                                          ares->message->elements[i].name);
-                        } else {
-                                new_attr = talloc_strndup(tmp_ctx,
-                                                          ares->message->elements[i].name,
-                                                          (size_t)(p -ares->message->elements[i].name));
-                                if (!new_attr) {
-                                        ldb_oom(ldb);
-                                        ret = LDB_ERR_OPERATIONS_ERROR;
-                                        goto fail;
-                                }
-                                attr =  dsdb_attribute_by_lDAPDisplayName(ac->schema,
-                                                                          new_attr);
-                                talloc_free(new_attr);
-                        }
-
+                        bool is_sd, is_objectsid, is_instancetype;
+                        uint32_t access_mask;
+                        attr =  dsdb_attribute_by_lDAPDisplayName(ac->schema,
+                                                                  msg->elements[i].name);
                         if (!attr) {
                                 DEBUG(2, ("acl_read: cannot find attribute %s in schema\n",
-                                          ares->message->elements[i].name));
+                                          msg->elements[i].name));
                                 ret = LDB_ERR_OPERATIONS_ERROR;
                                 goto fail;
                         }
+                        is_sd = ldb_attr_cmp("nTSecurityDescriptor",
+                                             msg->elements[i].name) == 0;
+                        is_objectsid = ldb_attr_cmp("objectSid",
+                                                    msg->elements[i].name) == 0;
+                        is_instancetype = ldb_attr_cmp("instanceType",
+                                                       msg->elements[i].name) == 0;
+                        /* these attributes were added to perform access checks and must be removed */
+                        if (is_objectsid && ac->object_sid) {
+                                aclread_mark_inaccesslible(&msg->elements[i]);
+                                continue;
+                        }
+                        if (is_instancetype && ac->instance_type) {
+                                aclread_mark_inaccesslible(&msg->elements[i]);
+                                continue;
+                        }
+                        if (is_sd && ac->sd) {
+                                aclread_mark_inaccesslible(&msg->elements[i]);
+                                continue;
+                        }
                         /* nTSecurityDescriptor is a special case */
-                        if (ldb_attr_cmp("nTSecurityDescriptor",
-                                         ares->message->elements[i].name) == 0) {
-                                ret = acl_check_access_on_attribute(ac->module,
-                                                                    tmp_ctx,
-                                                                    sd,
-                                                                    sid,
-                                                                    SEC_FLAG_SYSTEM_SECURITY|SEC_STD_READ_CONTROL,
-                                                                    attr);
+                        if (is_sd) {
+                                access_mask = SEC_FLAG_SYSTEM_SECURITY|SEC_STD_READ_CONTROL;
                         } else {
-                                ret = acl_check_access_on_attribute(ac->module,
-                                                                    tmp_ctx,
-                                                                    sd,
-                                                                    sid,
-                                                                    SEC_ADS_READ_PROP,
-                                                                    attr);
+                                access_mask = SEC_ADS_READ_PROP;
+                        }
+                        ret = acl_check_access_on_attribute(ac->module,
+                                                            tmp_ctx,
+                                                            sd,
+                                                            sid,
+                                                            access_mask,
+                                                            attr);
+
+                       /*
+                        * Dirsync control needs the replpropertymetadata attribute
+                        * so return it as it will be removed by the control
+                        * in anycase.
+                        */
+                       if (ret == LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS) {
+                               if (!ac->indirsync) {
+                                       /* do not return this entry if attribute is
+                                       part of the search filter */
+                                       if (dsdb_attr_in_parse_tree(ac->req->op.search.tree,
+                                                               msg->elements[i].name)) {
+                                               talloc_free(tmp_ctx);
+                                               return LDB_SUCCESS;
+                                       }
+                                       aclread_mark_inaccesslible(&msg->elements[i]);
+                               } else {
+                                       /*
+                                        * We are doing dirysnc answers
+                                        * and the object shouldn't be returned (normally)
+                                        * but we will return it without replPropertyMetaData
+                                        * so that the dirysync module will do what is needed
+                                        * (remove the object if it is not deleted, or return
+                                        * just the objectGUID if it's deleted).
+                                        */
+                                       if (dsdb_attr_in_parse_tree(ac->req->op.search.tree,
+                                                               msg->elements[i].name)) {
+                                               ldb_msg_remove_attr(msg, "replPropertyMetaData");
+                                       }
+                               }
+                       } else if (ret != LDB_SUCCESS) {
+                               goto fail;
+                       }
+                }
+                for (i=0; i < msg->num_elements; i++) {
+                        if (!aclread_is_inaccessible(&msg->elements[i])) {
+                                num_of_attrs++;
                         }
-                        if (ret == LDB_SUCCESS) {
-                                i++;
-                        } else if (ret == LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS) {
-                                /* do not return this entry if attribute is
-                                           part of the search filter */
-                                if (dsdb_attr_in_parse_tree(ac->req->op.search.tree,
-                                                            ares->message->elements[i].name)) {
-                                        talloc_free(tmp_ctx);
-                                        return LDB_SUCCESS;
+                }
+                /*create a new message to return*/
+                ret_msg = ldb_msg_new(ac->req);
+                ret_msg->dn = msg->dn;
+                talloc_steal(ret_msg, msg->dn);
+                ret_msg->num_elements = num_of_attrs;
+                if (num_of_attrs > 0) {
+                        ret_msg->elements = talloc_array(ret_msg,
+                                                         struct ldb_message_element,
+                                                         num_of_attrs);
+                        if (ret_msg->elements == NULL) {
+                                return ldb_oom(ldb);
+                        }
+                        for (i=0; i < msg->num_elements; i++) {
+                                bool to_remove = aclread_is_inaccessible(&msg->elements[i]);
+                                if (!to_remove) {
+                                        ret_msg->elements[k] = msg->elements[i];
+                                        talloc_steal(ret_msg->elements, msg->elements[i].name);
+                                        talloc_steal(ret_msg->elements, msg->elements[i].values);
+                                        k++;
                                 }
-                                ldb_msg_remove_attr(ares->message, ares->message->elements[i].name);
-                        } else {
-                                goto fail;
                         }
+                } else {
+                        ret_msg->elements = NULL;
                 }
                 talloc_free(tmp_ctx);
-                return ldb_module_send_entry(ac->req, ares->message, ares->controls);
+
+                return ldb_module_send_entry(ac->req, ret_msg, ares->controls);
         case LDB_REPLY_REFERRAL:
                 return ldb_module_send_referral(ac->req, ares->referral);
         case LDB_REPLY_DONE:
@@ -194,12 +245,14 @@ static int aclread_search(struct ldb_module *module, struct ldb_request *req)
        struct aclread_context *ac;
        struct ldb_request *down_req;
        struct ldb_control *as_system = ldb_request_get_control(req, LDB_CONTROL_AS_SYSTEM_OID);
+       struct ldb_control *indirsync = ldb_request_get_control(req, DSDB_CONTROL_DIRSYNC_RELAX_CHECK_OID);
        struct ldb_result *res;
-       struct ldb_message_element *parent;
        struct aclread_private *p;
        bool is_untrusted = ldb_req_is_untrusted(req);
+       const char * const *attrs = NULL;
+       uint32_t instanceType;
        static const char *acl_attrs[] = {
-                "parentGUID",
+                "instanceType",
                 NULL
        };
 
@@ -223,21 +276,22 @@ static int aclread_search(struct ldb_module *module, struct ldb_request *req)
                ret = dsdb_module_search_dn(module, req, &res, req->op.search.base,
                                            acl_attrs,
                                            DSDB_FLAG_NEXT_MODULE |
-                                           DSDB_SEARCH_SHOW_DELETED);
+                                           DSDB_SEARCH_SHOW_DELETED, req);
                if (ret != LDB_SUCCESS) {
                        return ldb_error(ldb, ret,
-                                        "acl_read: Error retrieving SD for base.");
+                                        "acl_read: Error retrieving instanceType for base.");
                }
-
-               parent = ldb_msg_find_element(res->msgs[0], "parentGUID");
-               if (parent) {
+               instanceType = ldb_msg_find_attr_as_uint(res->msgs[0],
+                                                        "instanceType", 0);
+               if (instanceType != 0 && !(instanceType & INSTANCE_TYPE_IS_NC_HEAD))
+               {
                        /* the object has a parent, so we have to check for visibility */
-                       struct GUID parent_guid = samdb_result_guid(res->msgs[0], "parentGUID");
-                       ret = dsdb_module_check_access_on_guid(module,
-                                                              req,
-                                                              &parent_guid,
-                                                              SEC_ADS_LIST,
-                                                              NULL);
+                       struct ldb_dn *parent_dn = ldb_dn_get_parent(req, req->op.search.base);
+                       ret = dsdb_module_check_access_on_dn(module,
+                                                            req,
+                                                            parent_dn,
+                                                            SEC_ADS_LIST,
+                                                            NULL, req);
                        if (ret == LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS) {
                                return ldb_module_done(req, NULL, NULL, LDB_ERR_NO_SUCH_OBJECT);
                        } else if (ret != LDB_SUCCESS) {
@@ -252,16 +306,43 @@ static int aclread_search(struct ldb_module *module, struct ldb_request *req)
        ac->module = module;
        ac->req = req;
        ac->schema = dsdb_get_schema(ldb, req);
+       if (indirsync != NULL) {
+               ac->indirsync = true;
+       } else {
+               ac->indirsync = false;
+       }
        if (!ac->schema) {
                return ldb_operr(ldb);
        }
+       ac->sd = !(ldb_attr_in_list(req->op.search.attrs, "nTSecurityDescriptor"));
+       if (req->op.search.attrs && !ldb_attr_in_list(req->op.search.attrs, "*")) {
+               if (!ldb_attr_in_list(req->op.search.attrs, "instanceType")) {
+                       ac->instance_type = true;
+                       attrs = ldb_attr_list_copy_add(ac, req->op.search.attrs, "instanceType");
+               } else {
+                       attrs = req->op.search.attrs;
+               }
+               if (!ldb_attr_in_list(req->op.search.attrs, "objectSid")) {
+                       ac->object_sid = true;
+                       attrs = ldb_attr_list_copy_add(ac, attrs, "objectSid");
+               }
+       }
 
+       if (ac->sd) {
+               /* avoid replacing all attributes with nTSecurityDescriptor
+                * if attribute list is empty */
+               if (!attrs) {
+                       attrs = ldb_attr_list_copy_add(ac, attrs, "*");
+               }
+               attrs = ldb_attr_list_copy_add(ac, attrs, "nTSecurityDescriptor");
+       }
+       ac->attrs = req->op.search.attrs;
        ret = ldb_build_search_req_ex(&down_req,
                                      ldb, ac,
                                      req->op.search.base,
                                      req->op.search.scope,
                                      req->op.search.tree,
-                                     req->op.search.attrs,
+                                     attrs,
                                      req->controls,
                                      ac, aclread_callback,
                                      req);