xen/ubsan: Fix UB in type_descriptor declaration

struct type_descriptor is arranged with a NUL terminated string following the
kind/info fields.

The only reason this doesn't trip UBSAN detection itself (on more modern
compilers at least) is because struct type_descriptor is only referenced in
suppressed regions.

Switch the declaration to be a real flexible member.  No functional change.

Fixes: 00fcf4dd8eb4 ("xen/ubsan: Import ubsan implementation from Linux 4.13")
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Release-Acked-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>

diff --git a/xen/common/ubsan/ubsan.h b/xen/common/ubsan/ubsan.h
index a3159040fefbdf7ba3d6bc794c8ee172a8ab83aa..3db42e75b13852c984a16c07d33b3834866cf5ee 100644 (file)
--- a/xen/common/ubsan/ubsan.h
+++ b/xen/common/ubsan/ubsan.h
@@ -10,7 +10,7 @@ enum {
 struct type_descriptor {
        u16 type_kind;
        u16 type_info;
-       char type_name[1];
+       char type_name[];
 };
 
 struct source_location {