From: John Wolfe <jwolfe@vmware.com>
Date: Sun, 21 Aug 2022 14:56:49 +0000 (-0700)
Subject: Common header file change not applicable to open-vm-tools.
X-Git-Tag: stable-12.1.0~9
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=08cac55b2a37fac30adfb090748ca2b96c3256db;p=thirdparty%2Fopen-vm-tools.git

Common header file change not applicable to open-vm-tools.
---

diff --git a/open-vm-tools/lib/include/vm_atomic.h b/open-vm-tools/lib/include/vm_atomic.h
index 4cdddf336..a1ab55dcd 100644
--- a/open-vm-tools/lib/include/vm_atomic.h
+++ b/open-vm-tools/lib/include/vm_atomic.h
@@ -1521,7 +1521,21 @@ Atomic_Sub32(Atomic_uint32 *var, // IN/OUT
    );
 #endif /* VM_X86_ANY */
 #elif defined _MSC_VER
-   _InterlockedExchangeAdd((long *)&var->value, -(long)val);
+   /*
+    * Microsoft warning C4146, enabled by the /sdl option for
+    * additional security checks, objects to `-val' when val is
+    * unsigned, even though that is always well-defined by C and has
+    * exactly the semantics we want, namely negation modulo 2^32.
+    * (The signed version, in contrast, has undefined behaviour at
+    * some inputs.)
+    *
+    * https://docs.microsoft.com/en-us/cpp/error-messages/compiler-warnings/compiler-warning-level-2-c4146?view=msvc-170
+    * https://docs.microsoft.com/en-us/cpp/build/reference/sdl-enable-additional-security-checks?view=msvc-170
+    */
+#   pragma warning(push)
+#   pragma warning(disable: 4146)
+   _InterlockedExchangeAdd((long *)&var->value, (long)-val);
+#   pragma warning(pop)
 #else
 #error No compiler defined for Atomic_Sub
 #endif
@@ -2229,7 +2243,25 @@ Atomic_ReadSub64(Atomic_uint64 *var, // IN/OUT
 #if defined __GNUC__ && defined VM_ARM_64
    return _VMATOM_X(ROP, 64, TRUE, &var->value, sub, val);
 #else
-   return Atomic_ReadAdd64(var, (uint64)-(int64)val);
+#   ifdef _MSC_VER
+   /*
+    * Microsoft warning C4146, enabled by the /sdl option for
+    * additional security checks, objects to `-val' when val is
+    * unsigned, even though that is always well-defined by C and has
+    * exactly the semantics we want, namely negation modulo 2^64.
+    * (The signed version, in contrast, has undefined behaviour at
+    * some inputs.)
+    *
+    * https://docs.microsoft.com/en-us/cpp/error-messages/compiler-warnings/compiler-warning-level-2-c4146?view=msvc-170
+    * https://docs.microsoft.com/en-us/cpp/build/reference/sdl-enable-additional-security-checks?view=msvc-170
+    */
+#      pragma warning(push)
+#      pragma warning(disable: 4146)
+#   endif
+   return Atomic_ReadAdd64(var, -val);
+#   ifdef _MSC_VER
+#      pragma warning(pop)
+#   endif
 #endif
 }