From: krw <krw@openbsd.org>
Date: Fri, 2 Sep 2022 12:24:26 +0000 (+0000)
Subject: Relax GTP header validity check by allowing 1 sector size usable
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=9dfb435af5176bab3d98bfc6210d550575e6bd66;p=openbsd

Relax GTP header validity check by allowing 1 sector size usable
LBA area (gh_lba_start == gh_lba_end) and allowing either or both
of gh_lba_start and gh_lba_end to exceed the size of the disk the
GPT currently inhabits.

Reduces false negatives and inappropriate fall through to MBR
spoofing and allows repair of otherwise valid GPT.
---

diff --git a/sys/kern/subr_disk.c b/sys/kern/subr_disk.c
index 94a67927f3e..cac0b450026 100644
--- a/sys/kern/subr_disk.c
+++ b/sys/kern/subr_disk.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: subr_disk.c,v 1.255 2022/09/01 13:45:27 krw Exp $	*/
+/*	$OpenBSD: subr_disk.c,v 1.256 2022/09/02 12:24:26 krw Exp $	*/
 /*	$NetBSD: subr_disk.c,v 1.17 1996/03/16 23:17:08 christos Exp $	*/
 
 /*
@@ -484,8 +484,7 @@ gpt_get_hdr(struct buf *bp, void (*strat)(struct buf *), struct disklabel *lp,
 
 	if (letoh64(ngh.gh_sig) == GPTSIGNATURE &&
 	    letoh32(ngh.gh_rev) == GPTREVISION &&
-	    size == GPTMINHDRSIZE && lbastart < lbaend &&
-	    lbastart < DL_GETDSIZE(lp) && lbaend < DL_GETDSIZE(lp) &&
+	    size == GPTMINHDRSIZE && lbastart <= lbaend &&
 	    partsize == GPTMINPARTSIZE && lp->d_secsize % partsize == 0 &&
 	    csum == ngh.gh_csum)
 		*gh = ngh;