From: Andrew Cooper <andrew.cooper3@citrix.com>
Date: Wed, 26 Jun 2024 12:12:38 +0000 (+0200)
Subject: xen/ubsan: Fix UB in type_descriptor declaration
X-Git-Tag: RELEASE-4.17.5~35
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=9dfe294cb6de52c34f1419394fde1fe2b6c2a70b;p=xen.git

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>
master commit: bd59af99700f075d06a6d47a16f777c9519928e0
master date: 2024-06-18 14:55:04 +0100
---

diff --git a/xen/common/ubsan/ubsan.h b/xen/common/ubsan/ubsan.h
index a3159040fe..3db42e75b1 100644
--- 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 {