Setting UFN prefix to NULL should clear prefix, not cause crash

CHANGES

@@ -7,6 +7,7 @@ Changes included in OpenLDAP 1.2.11 Release Engineering
 	Fix slurpd to properly restart in oneshot mode, and to report a
 		non-zero number of items to process with only one replica.
 	Fix strdup use in libldap/request.c
+	Fix NULL prefix bug in libldap/ufn.c
 
 Changes included in OpenLDAP 1.2.10
 	CVS Tag: OPENLDAP_REL_ENG_1_2_10

libraries/libldap/ufn.c

@@ -476,7 +476,8 @@ ldap_ufn_setprefix( LDAP *ld, char *prefix )
 	if ( ld->ld_ufnprefix != NULL )
 		free( ld->ld_ufnprefix );
 
-	ld->ld_ufnprefix = ldap_strdup( prefix );
+	ld->ld_ufnprefix = prefix == NULL
+		? NULL : ldap_strdup( prefix );
 }
 
 int