From: millert <millert@openbsd.org>
Date: Wed, 13 Apr 2022 16:23:53 +0000 (+0000)
Subject: ftok: avoid left shift of a signed in by 24 places
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=33a09bee3ffed2ecb0af3ed6458fb773695c6eb7;p=openbsd

ftok: avoid left shift of a signed in by 24 places
Fix "left shift of 255 by 24 places cannot be represented in type 'int'"
error from UBSAN.  Adapted from a FreeBSD diff via tb@.  OK tb@ deraadt@
---

diff --git a/lib/libc/gen/ftok.c b/lib/libc/gen/ftok.c
index ea1edf1afd9..9edcd30005a 100644
--- a/lib/libc/gen/ftok.c
+++ b/lib/libc/gen/ftok.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ftok.c,v 1.9 2019/06/28 13:32:41 deraadt Exp $ */
+/*	$OpenBSD: ftok.c,v 1.10 2022/04/13 16:23:53 millert Exp $ */
 /*
  * Copyright (c) 1994 SigmaSoft, Th. Lockert <tholo@sigmasoft.com>
  * All rights reserved.
@@ -32,11 +32,12 @@
 key_t
 ftok(const char *path, int id)
 {
+	const unsigned int u_id = id;
 	struct stat st;
 
 	if (stat(path, &st) == -1)
 		return (key_t)-1;
 
 	return (key_t)
-	    ((id & 0xff) << 24 | (st.st_dev & 0xff) << 16 | (st.st_ino & 0xffff));
+	    ((u_id & 0xff) << 24 | (st.st_dev & 0xff) << 16 | (st.st_ino & 0xffff));
 }