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 ea1edf1..9edcd30 100644 (file)
--- 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));
 }