Index: shadow-4.1.4.2/libmisc/chkname.c
===================================================================
--- shadow-4.1.4.2.orig/libmisc/chkname.c	2009-04-28 12:14:04.000000000 -0700
+++ shadow-4.1.4.2/libmisc/chkname.c	2010-06-03 17:43:20.638973857 -0700
@@ -61,6 +61,7 @@ static bool is_valid_name (const char *n
 		      ( ('0' <= *name) && ('9' >= *name) ) ||
 		      ('_' == *name) ||
 		      ('-' == *name) ||
+		      ('.' == *name) ||
 		      ( ('$' == *name) && ('\0' == *(name + 1)) )
 		     )) {
 			return false;