From: Pali Rohár <pali@kernel.org>
Date: Sat, 20 Jan 2024 11:30:08 +0000 (+0100)
Subject: libpci: physmem-posix: Fix OFF_MAX definition
X-Git-Tag: v3.11.0~16
X-Git-Url: http://mj.ucw.cz/gitweb/?a=commitdiff_plain;h=155f087b19681f043cd65283559a7a8dea08c85a;p=pciutils.git

libpci: physmem-posix: Fix OFF_MAX definition

Expression ((1 << n) - 1) for n=31 has undefined behavior and gcc 11
already evaluates it to zero.

Fix definition of OFF_MAX to prevent signed integer overflow.
---

diff --git a/lib/physmem-posix.c b/lib/physmem-posix.c
index 664ec48..7cd7e99 100644
--- a/lib/physmem-posix.c
+++ b/lib/physmem-posix.c
@@ -26,7 +26,7 @@
 #include <unistd.h>
 
 #ifndef OFF_MAX
-#define OFF_MAX (off_t)((1ULL << (sizeof(off_t) * CHAR_BIT - 1)) - 1)
+#define OFF_MAX ((((off_t)1 << (sizeof(off_t) * CHAR_BIT - 2)) - 1) * 2 + 1)
 #endif
 
 struct physmem {