s4:dsdb - introduce a new "objectclass_attrs" LDB module which performs the objectclass attributes checking

Until now we had no real consistent mechanism which allowed us to check if
attributes belong to the specified objectclasses.

3 files changed, 401 insertions, 0 deletions

diff --git a/source4/dsdb/samdb/ldb_modules/objectclass_attrs.c b/source4/dsdb/samdb/ldb_modules/objectclass_attrs.c
new file mode 100644
index 0000000000..042d26b981
--- /dev/null
+++ b/source4/dsdb/samdb/ldb_modules/objectclass_attrs.c
@@ -0,0 +1,392 @@
+/*
+   ldb database library
+
+   Copyright (C) Simo Sorce  2006-2008
+   Copyright (C) Andrew Bartlett <abartlet@samba.org> 2005-2009
+   Copyright (C) Stefan Metzmacher 2009
+   Copyright (C) Matthias Dieter Wallnöfer 2010
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with this library; if not, see <http://www.gnu.org/licenses/>.
+*/
+
+/*
+ *  Name: ldb
+ *
+ *  Component: objectclass attribute checking module
+ *
+ *  Description: this checks the attributes on a directory entry (if they're
+ *    allowed, if the syntax is correct, if mandatory ones are missing,
+ *    denies the deletion of mandatory ones...). The module contains portions
+ *    of the "objectclass" and the "validate_update" LDB module.
+ *
+ *  Author: Matthias Dieter Wallnöfer
+ */
+
+#include "includes.h"
+#include "ldb_module.h"
+#include "dsdb/samdb/samdb.h"
+
+struct oc_context {
+
+	struct ldb_module *module;
+	struct ldb_request *req;
+	const struct dsdb_schema *schema;
+
+	struct ldb_reply *search_res;
+	struct ldb_reply *mod_ares;
+};
+
+static struct oc_context *oc_init_context(struct ldb_module *module,
+					  struct ldb_request *req)
+{
+	struct ldb_context *ldb;
+	struct oc_context *ac;
+
+	ldb = ldb_module_get_ctx(module);
+
+	ac = talloc_zero(req, struct oc_context);
+	if (ac == NULL) {
+		ldb_oom(ldb);
+		return NULL;
+	}
+
+	ac->module = module;
+	ac->req = req;
+	ac->schema = dsdb_get_schema(ldb, ac);
+
+	return ac;
+}
+
+static int oc_op_callback(struct ldb_request *req, struct ldb_reply *ares);
+
+static int attr_handler(struct oc_context *ac)
+{
+	struct ldb_context *ldb;
+	struct ldb_message *msg;
+	struct ldb_request *child_req;
+	const struct dsdb_attribute *attr;
+	unsigned int i;
+	int ret;
+	WERROR werr;
+
+	ldb = ldb_module_get_ctx(ac->module);
+
+	if (ac->req->operation == LDB_ADD) {
+		msg = ldb_msg_copy_shallow(ac, ac->req->op.add.message);
+	} else {
+		msg = ldb_msg_copy_shallow(ac, ac->req->op.mod.message);
+	}
+	if (msg == NULL) {
+		ldb_oom(ldb);
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+	/* Check if attributes exist in the schema, if the values match,
+	 * if they're not operational and fix the names to the match the schema
+	 * case */
+	for (i = 0; i < msg->num_elements; i++) {
+		attr = dsdb_attribute_by_lDAPDisplayName(ac->schema,
+							 msg->elements[i].name);
+		if (attr == NULL) {
+			ldb_asprintf_errstring(ldb, "objectclass_attrs: attribute '%s' on entry '%s' was not found in the schema!",
+					       msg->elements[i].name,
+					       ldb_dn_get_linearized(msg->dn));
+			return LDB_ERR_NO_SUCH_ATTRIBUTE;
+		}
+
+		werr = attr->syntax->validate_ldb(ldb, ac->schema, attr,
+						  &msg->elements[i]);
+		if (!W_ERROR_IS_OK(werr)) {
+			ldb_asprintf_errstring(ldb, "objectclass_attrs: attribute '%s' on entry '%s' contains at least one invalid value!",
+					       msg->elements[i].name,
+					       ldb_dn_get_linearized(msg->dn));
+			return LDB_ERR_INVALID_ATTRIBUTE_SYNTAX;
+		}
+
+		if ((attr->systemFlags & DS_FLAG_ATTR_IS_CONSTRUCTED) != 0) {
+			ldb_asprintf_errstring(ldb, "objectclass_attrs: attribute '%s' on entry '%s' is constructed!",
+					       msg->elements[i].name,
+					       ldb_dn_get_linearized(msg->dn));
+			if (ac->req->operation == LDB_ADD) {
+				return LDB_ERR_UNDEFINED_ATTRIBUTE_TYPE;
+			} else {
+				return LDB_ERR_CONSTRAINT_VIOLATION;
+			}
+		}
+
+		/* subsitute the attribute name to match in case */
+		msg->elements[i].name = attr->lDAPDisplayName;
+	}
+
+	if (ac->req->operation == LDB_ADD) {
+		ret = ldb_build_add_req(&child_req, ldb, ac,
+					msg, ac->req->controls,
+					ac, oc_op_callback, ac->req);
+	} else {
+		ret = ldb_build_mod_req(&child_req, ldb, ac,
+					msg, ac->req->controls,
+					ac, oc_op_callback, ac->req);
+	}
+	if (ret != LDB_SUCCESS) {
+		return ret;
+	}
+
+	return ldb_next_request(ac->module, child_req);
+}
+
+static int attr_handler2(struct oc_context *ac)
+{
+	struct ldb_context *ldb;
+	struct ldb_message_element *oc_element;
+	struct ldb_message *msg;
+	const char **must_contain, **may_contain, **found_must_contain;
+	const struct dsdb_attribute *attr;
+	unsigned int i;
+	bool found;
+
+	ldb = ldb_module_get_ctx(ac->module);
+
+	if (ac->search_res == NULL) {
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+	/* We rely here on the preceeding "objectclass" LDB module which did
+	 * already fix up the objectclass list (inheritance, order...). */
+	oc_element = ldb_msg_find_element(ac->search_res->message,
+					  "objectClass");
+	if (oc_element == NULL) {
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+	must_contain = dsdb_full_attribute_list(ac, ac->schema, oc_element,
+						DSDB_SCHEMA_ALL_MUST);
+	may_contain =  dsdb_full_attribute_list(ac, ac->schema, oc_element,
+						DSDB_SCHEMA_ALL_MAY);
+	found_must_contain = const_str_list(str_list_copy(ac, must_contain));
+	if ((must_contain == NULL) || (may_contain == NULL)
+	    || (found_must_contain == NULL)) {
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+	/* Check if all specified attributes are valid in the given
+	 * objectclasses. */
+	msg = ac->search_res->message;
+	for (i = 0; i < msg->num_elements; i++) {
+		attr = dsdb_attribute_by_lDAPDisplayName(ac->schema,
+							 msg->elements[i].name);
+		if (attr == NULL) {
+			return LDB_ERR_OPERATIONS_ERROR;
+		}
+
+		/* We can use "str_list_check" with "strcmp" here since the
+		 * attribute informations from the schema are always equal
+		 * up-down-cased. */
+		found = str_list_check(must_contain, attr->lDAPDisplayName);
+		if (found) {
+			str_list_remove(found_must_contain, attr->lDAPDisplayName);
+		} else {
+			found = str_list_check(may_contain, attr->lDAPDisplayName);
+		}
+		if (!found) {
+			ldb_asprintf_errstring(ldb, "objectclass_attrs: attribute '%s' on entry '%s' does not exist in the specified objectclasses!",
+					       msg->elements[i].name,
+					       ldb_dn_get_linearized(msg->dn));
+			return LDB_ERR_OBJECT_CLASS_VIOLATION;
+		}
+	}
+
+	if (found_must_contain[0] != NULL) {
+		ldb_asprintf_errstring(ldb, "objectclass_attrs: at least one mandatory attribute ('%s') on entry '%s' wasn't specified!",
+				       found_must_contain[0],
+				       ldb_dn_get_linearized(msg->dn));
+		return LDB_ERR_OBJECT_CLASS_VIOLATION;
+	}
+
+	return ldb_module_done(ac->req, ac->mod_ares->controls,
+			       ac->mod_ares->response, LDB_SUCCESS);
+}
+
+static int get_search_callback(struct ldb_request *req, struct ldb_reply *ares)
+{
+	struct ldb_context *ldb;
+	struct oc_context *ac;
+	int ret;
+
+	ac = talloc_get_type(req->context, struct oc_context);
+	ldb = ldb_module_get_ctx(ac->module);
+
+	if (!ares) {
+		return ldb_module_done(ac->req, NULL, NULL,
+				       LDB_ERR_OPERATIONS_ERROR);
+	}
+	if (ares->error != LDB_SUCCESS) {
+		return ldb_module_done(ac->req, ares->controls,
+				       ares->response, ares->error);
+	}
+
+	ldb_reset_err_string(ldb);
+
+	switch (ares->type) {
+	case LDB_REPLY_ENTRY:
+		if (ac->search_res != NULL) {
+			ldb_set_errstring(ldb, "Too many results");
+			talloc_free(ares);
+			return ldb_module_done(ac->req, NULL, NULL,
+					       LDB_ERR_OPERATIONS_ERROR);
+		}
+
+		ac->search_res = talloc_steal(ac, ares);
+		break;
+
+	case LDB_REPLY_REFERRAL:
+		/* ignore */
+		talloc_free(ares);
+		break;
+
+	case LDB_REPLY_DONE:
+		talloc_free(ares);
+		ret = attr_handler2(ac);
+		if (ret != LDB_SUCCESS) {
+			return ldb_module_done(ac->req, NULL, NULL, ret);
+		}
+		break;
+	}
+
+	return LDB_SUCCESS;
+}
+
+static int oc_op_callback(struct ldb_request *req, struct ldb_reply *ares)
+{
+	struct oc_context *ac;
+	struct ldb_context *ldb;
+	struct ldb_request *search_req;
+	struct ldb_dn *base_dn;
+	int ret;
+
+	ac = talloc_get_type(req->context, struct oc_context);
+	ldb = ldb_module_get_ctx(ac->module);
+
+	if (!ares) {
+		return ldb_module_done(ac->req, NULL, NULL,
+				       LDB_ERR_OPERATIONS_ERROR);
+	}
+
+	if (ares->type == LDB_REPLY_REFERRAL) {
+		return ldb_module_send_referral(ac->req, ares->referral);
+	}
+
+	if (ares->error != LDB_SUCCESS) {
+		return ldb_module_done(ac->req, ares->controls, ares->response,
+				       ares->error);
+	}
+
+	if (ares->type != LDB_REPLY_DONE) {
+		talloc_free(ares);
+		return ldb_module_done(ac->req, NULL, NULL,
+				       LDB_ERR_OPERATIONS_ERROR);
+	}
+
+	ac->search_res = NULL;
+	ac->mod_ares = talloc_steal(ac, ares);
+
+	/* This looks up all attributes of our just added/modified entry */
+	base_dn = ac->req->operation == LDB_ADD ? ac->req->op.add.message->dn
+		: ac->req->op.mod.message->dn;
+	ret = ldb_build_search_req(&search_req, ldb, ac, base_dn,
+				   LDB_SCOPE_BASE, "(objectClass=*)",
+				   NULL, NULL, ac,
+				   get_search_callback, ac->req);
+	if (ret != LDB_SUCCESS) {
+		return ldb_module_done(ac->req, NULL, NULL, ret);
+	}
+
+	ret = ldb_request_add_control(search_req, LDB_CONTROL_SHOW_DELETED_OID,
+				      true, NULL);
+	if (ret != LDB_SUCCESS) {
+		return ldb_module_done(ac->req, NULL, NULL, ret);
+	}
+
+	ret = ldb_next_request(ac->module, search_req);
+	if (ret != LDB_SUCCESS) {
+		return ldb_module_done(ac->req, NULL, NULL, ret);
+	}
+
+	/* "ldb_module_done" isn't called here since we need to do additional
+	 * checks. It is called at the end of "attr_handler2". */
+	return LDB_SUCCESS;
+}
+
+static int objectclass_attrs_add(struct ldb_module *module,
+				 struct ldb_request *req)
+{
+	struct ldb_context *ldb;
+	struct oc_context *ac;
+
+	ldb = ldb_module_get_ctx(module);
+
+	ldb_debug(ldb, LDB_DEBUG_TRACE, "objectclass_attrs_add\n");
+
+	/* do not manipulate our control entries */
+	if (ldb_dn_is_special(req->op.add.message->dn)) {
+		return ldb_next_request(module, req);
+	}
+
+	ac = oc_init_context(module, req);
+	if (ac == NULL) {
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+	/* without schema, there isn't much to do here */
+	if (ac->schema == NULL) {
+		talloc_free(ac);
+		return ldb_next_request(module, req);
+	}
+
+	return attr_handler(ac);
+}
+
+static int objectclass_attrs_modify(struct ldb_module *module,
+				    struct ldb_request *req)
+{
+	struct ldb_context *ldb;
+	struct oc_context *ac;
+
+	ldb = ldb_module_get_ctx(module);
+
+	ldb_debug(ldb, LDB_DEBUG_TRACE, "objectclass_attrs_modify\n");
+
+	/* do not manipulate our control entries */
+	if (ldb_dn_is_special(req->op.mod.message->dn)) {
+		return ldb_next_request(module, req);
+	}
+
+	ac = oc_init_context(module, req);
+	if (ac == NULL) {
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+	/* without schema, there isn't much to do here */
+	if (ac->schema == NULL) {
+		talloc_free(ac);
+		return ldb_next_request(module, req);
+	}
+
+	return attr_handler(ac);
+}
+
+_PUBLIC_ const struct ldb_module_ops ldb_objectclass_attrs_module_ops = {
+	.name		   = "objectclass_attrs",
+	.add               = objectclass_attrs_add,
+	.modify            = objectclass_attrs_modify
+};
diff --git a/source4/dsdb/samdb/ldb_modules/samba_dsdb.c b/source4/dsdb/samdb/ldb_modules/samba_dsdb.c
index bbdb768705..ebd2f13ab6 100644
--- a/source4/dsdb/samdb/ldb_modules/samba_dsdb.c
+++ b/source4/dsdb/samdb/ldb_modules/samba_dsdb.c
@@ -181,6 +181,7 @@ static int samba_dsdb_init(struct ldb_module *module)
 					     "samldb",
 					     "password_hash",
 					     "operational",
+					     "objectclass_attrs",
 					     "validate_update",
 					     "kludge_acl",
 					     "schema_load",
diff --git a/source4/dsdb/samdb/ldb_modules/wscript_build b/source4/dsdb/samdb/ldb_modules/wscript_build
index 0a222fea45..dfcc2665eb 100644
--- a/source4/dsdb/samdb/ldb_modules/wscript_build
+++ b/source4/dsdb/samdb/ldb_modules/wscript_build
@@ -210,6 +210,14 @@ bld.SAMBA_MODULE('ldb_objectclass',
 	)
 
 
+bld.SAMBA_MODULE('ldb_objectclass_attrs',
+	source='objectclass_attrs.c',
+	subsystem='LIBLDB',
+	init_function='LDB_MODULE(objectclass_attrs)',
+	deps='talloc SAMDB LIBSAMBA-UTIL'
+	)
+
+
 bld.SAMBA_MODULE('ldb_subtree_rename',
 	source='subtree_rename.c',
 	subsystem='LIBLDB',