[src/trunk]: src/sys/kern Avoid division by zero if label isn't valid.

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

details:   https://anonhg.NetBSD.org/src/rev/fd47dfad4286
branches:  trunk
changeset: 1008580:fd47dfad4286
user:      mlelstv <mlelstv%NetBSD.org@localhost>
date:      Fri Mar 27 11:13:57 2020 +0000

description:
Avoid division by zero if label isn't valid.

diffstat:

 sys/kern/subr_disk.c |  8 ++++++--
 1 files changed, 6 insertions(+), 2 deletions(-)

diffs (29 lines):

diff -r 86cd64488cb5 -r fd47dfad4286 sys/kern/subr_disk.c
--- a/sys/kern/subr_disk.c      Fri Mar 27 11:10:07 2020 +0000
+++ b/sys/kern/subr_disk.c      Fri Mar 27 11:13:57 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: subr_disk.c,v 1.129 2019/09/30 23:23:59 cnst Exp $     */
+/*     $NetBSD: subr_disk.c,v 1.130 2020/03/27 11:13:57 mlelstv Exp $  */
 
 /*-
  * Copyright (c) 1996, 1997, 1999, 2000, 2009 The NetBSD Foundation, Inc.
@@ -67,7 +67,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: subr_disk.c,v 1.129 2019/09/30 23:23:59 cnst Exp $");
+__KERNEL_RCSID(0, "$NetBSD: subr_disk.c,v 1.130 2020/03/27 11:13:57 mlelstv Exp $");
 
 #include <sys/param.h>
 #include <sys/kernel.h>
@@ -440,6 +440,10 @@
 disk_read_sectors(void (*strat)(struct buf *), const struct disklabel *lp,
     struct buf *bp, unsigned int sector, int count)
 {
+
+       if ((lp->d_secsize / DEV_BSIZE) == 0 || lp->d_secpercyl == 0)
+               return EINVAL;
+
        bp->b_blkno = btodb((off_t)sector * lp->d_secsize);
        bp->b_bcount = count * lp->d_secsize;
        bp->b_flags = (bp->b_flags & ~B_WRITE) | B_READ;