[src/trunk]: src/usr.sbin/sysinst Avoid integer arithmetic overflow when chec...

[martin <martin%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/97fd471a91d0
branches:  trunk
changeset: 366745:97fd471a91d0
user:      martin <martin%NetBSD.org@localhost>
date:      Sat Jun 11 18:27:22 2022 +0000

description:
Avoid integer arithmetic overflow when checking a partition table without
any partitions.
Fix some comments.

diffstat:

 usr.sbin/sysinst/label.c |  9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)

diffs (37 lines):

diff -r e7af808ca1f3 -r 97fd471a91d0 usr.sbin/sysinst/label.c
--- a/usr.sbin/sysinst/label.c  Sat Jun 11 18:17:00 2022 +0000
+++ b/usr.sbin/sysinst/label.c  Sat Jun 11 18:27:22 2022 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: label.c,v 1.35 2022/06/11 15:41:19 martin Exp $        */
+/*     $NetBSD: label.c,v 1.36 2022/06/11 18:27:22 martin Exp $        */
 
 /*
  * Copyright 1997 Jonathan Stone
@@ -36,7 +36,7 @@
 
 #include <sys/cdefs.h>
 #if defined(LIBC_SCCS) && !defined(lint)
-__RCSID("$NetBSD: label.c,v 1.35 2022/06/11 15:41:19 martin Exp $");
+__RCSID("$NetBSD: label.c,v 1.36 2022/06/11 18:27:22 martin Exp $");
 #endif
 
 #include <sys/types.h>
@@ -101,7 +101,7 @@
 
 /*
  * Check partitioning for overlapping partitions.
- * Returns 0 if no overlapping partition found, nonzero otherwise.
+ * Returns true if no overlapping partition found.
  * Sets reference arguments ovly1 and ovly2 to the indices of
  * overlapping partitions if any are found.
  */
@@ -114,6 +114,9 @@
        daddr_t istart, iend, jstart, jend;
        unsigned int fs_type, fs_sub_type;
 
+       if (parts->num_part == 0)
+               return true;
+
        for (i = 0; i < parts->num_part - 1; i ++ ) {
                if (!parts->pscheme->get_part_info(parts, i, &info))
                        continue;