Index: lib/ldb/common/ldb.c
===================================================================
--- lib/ldb/common/ldb.c	(revision 24649)
+++ lib/ldb/common/ldb.c	(working copy)
@@ -115,7 +115,7 @@
 	char *backend;
 	ldb_connect_fn fn;
 
-	if (strchr(url, ':') != NULL) {
+	if ((url) && (strchr(url, ':') != NULL)) {
 		backend = talloc_strndup(ldb, url, strchr(url, ':')-url);
 	} else {
 		/* Default to tdb */
Index: lib/ldb/ldb_tdb/ldb_tdb.c
===================================================================
--- lib/ldb/ldb_tdb/ldb_tdb.c	(revision 24649)
+++ lib/ldb/ldb_tdb/ldb_tdb.c	(working copy)
@@ -1010,8 +1010,8 @@
 	struct ltdb_private *ltdb;
 
 	/* parse the url */
-	if (strchr(url, ':')) {
-		if (strncmp(url, "tdb://", 6) != 0) {
+	if ((!url) || (strchr(url, ':'))) {
+		if ((!url) || (strncmp(url, "tdb://", 6) != 0)) {
 			ldb_debug(ldb, LDB_DEBUG_ERROR, "Invalid tdb URL '%s'", url);
 			return -1;
 		}
Index: dsdb/samdb/ldb_modules/partition.c
===================================================================
--- dsdb/samdb/ldb_modules/partition.c	(revision 24649)
+++ dsdb/samdb/ldb_modules/partition.c	(working copy)
@@ -724,7 +724,7 @@
 		p[0] = '\0';
 	} else {
 		talloc_free(path);
-		return NULL;
+		path = talloc_asprintf(mem_ctx, "%s", ".");
 	}
 	full_name = talloc_asprintf(mem_ctx, "%s/%s", path, name);
 	talloc_free(path);