From 95a0034f4744010132a3b3b267caa55a215db072 Mon Sep 17 00:00:00 2001
From: krw <krw@openbsd.org>
Date: Sun, 11 Sep 2022 11:47:55 +0000
Subject: [PATCH] Add #define's for GPT partition attribute bits REQUIRED,
 IGNORE and BOOTABLE, set BOOTABLE attribute bit instead of using the
 incorrect GPTDOSACTIVE value, have 'fdisk -v' print out GPT partition
 attributes if any of the 64 bits are set, don't spoof any partition with
 REQUIRED bit set.

Prompted by kettenis@ stumbling across a machine with 40+ (!!)
REQUIRED GPT partitions.

Tested & ok kettenis@
---
 sbin/fdisk/cmd.c     |  4 ++--
 sbin/fdisk/gpt.c     | 21 ++++++++++++++++-----
 sys/kern/subr_disk.c |  7 ++++++-
 sys/sys/disklabel.h  |  5 ++++-
 4 files changed, 28 insertions(+), 9 deletions(-)

diff --git a/sbin/fdisk/cmd.c b/sbin/fdisk/cmd.c
index dc8698901b9..99146bfc22e 100644
--- a/sbin/fdisk/cmd.c
+++ b/sbin/fdisk/cmd.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cmd.c,v 1.164 2022/07/25 17:45:16 krw Exp $	*/
+/*	$OpenBSD: cmd.c,v 1.165 2022/09/11 11:47:55 krw Exp $	*/
 
 /*
  * Copyright (c) 1997 Tobias Weingartner
@@ -488,7 +488,7 @@ Xflag(const char *args, struct mbr *mbr)
 		if (gh.gh_sig == GPTSIGNATURE) {
 			for (i = 0; i < gh.gh_part_num; i++) {
 				if (i == pn)
-					gp[i].gp_attrs = GPTDOSACTIVE;
+					gp[i].gp_attrs = GPTPARTATTR_BOOTABLE;
 				else
 					gp[i].gp_attrs = 0;
 			}
diff --git a/sbin/fdisk/gpt.c b/sbin/fdisk/gpt.c
index 247c7d2699c..c3f66ca7ebb 100644
--- a/sbin/fdisk/gpt.c
+++ b/sbin/fdisk/gpt.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: gpt.c,v 1.80 2022/08/29 19:39:10 krw Exp $	*/
+/*	$OpenBSD: gpt.c,v 1.81 2022/09/11 11:47:55 krw Exp $	*/
 /*
  * Copyright (c) 2015 Markus Muller <mmu@grummel.net>
  * Copyright (c) 2015 Kenneth R Westerback <krw@openbsd.org>
@@ -437,15 +437,14 @@ GPT_print_part(const unsigned int pn, const char *units, const int verbosity)
 	const struct unit_type	*ut;
 	char			*guidstr = NULL;
 	double			 size;
-	uint64_t		 end, start;
+	uint64_t		 attrs, end, start;
 	uint32_t		 status;
 
 	start = gp[pn].gp_lba_start;
 	end = gp[pn].gp_lba_end;
 	size = units_size(units, (start > end) ? 0 : end - start + 1, &ut);
 
-	printf("%c%3u: %-36s [%12lld: %12.0f%s]\n",
-	    gp[pn].gp_attrs & GPTDOSACTIVE ? '*' : ' ', pn,
+	printf(" %3u: %-36s [%12lld: %12.0f%s]\n", pn,
 	    PRT_uuid_to_sname(&gp[pn].gp_type), start, size, ut->ut_abbr);
 
 	if (verbosity == VERBOSE) {
@@ -456,6 +455,17 @@ GPT_print_part(const unsigned int pn, const char *units, const int verbosity)
 			printf("      %-36s ", guidstr);
 		printf("%-36s\n", name_to_string(pn));
 		free(guidstr);
+		attrs = gp[pn].gp_attrs;
+		if (attrs) {
+			printf("      Attributes: (0x%016llx) ", attrs);
+			if (attrs & GPTPARTATTR_REQUIRED)
+				printf("Required " );
+			if (attrs & GPTPARTATTR_IGNORE)
+				printf("Ignore ");
+			if (attrs & GPTPARTATTR_BOOTABLE)
+				printf("Bootable");
+			printf("\n");
+		}
 	}
 
 	if (start > end)
@@ -592,7 +602,8 @@ init_gp(const int how)
 		memset(&gp, 0, sizeof(gp));
 	else {
 		for (pn = 0; pn < gh.gh_part_num; pn++) {
-			if (PRT_protected_guid(&gp[pn].gp_type))
+			if (PRT_protected_guid(&gp[pn].gp_type) ||
+			    (gp[pn].gp_attrs & GPTPARTATTR_REQUIRED))
 				continue;
 			memset(&gp[pn], 0, sizeof(gp[pn]));
 		}
diff --git a/sys/kern/subr_disk.c b/sys/kern/subr_disk.c
index b35cbb4e052..6623dd816bc 100644
--- a/sys/kern/subr_disk.c
+++ b/sys/kern/subr_disk.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: subr_disk.c,v 1.260 2022/09/03 15:29:43 kettenis Exp $	*/
+/*	$OpenBSD: subr_disk.c,v 1.261 2022/09/11 11:47:55 krw Exp $	*/
 /*	$NetBSD: subr_disk.c,v 1.17 1996/03/16 23:17:08 christos Exp $	*/
 
 /*
@@ -641,6 +641,11 @@ spoofgpt(struct buf *bp, void (*strat)(struct buf *), const uint8_t *dosbb,
 	partoff = DL_SECTOBLK(lp, lbastart);
 	obsdfound = 0;
 	for (i = 0; i < partnum; i++) {
+		if (letoh64(gp[i].gp_attrs) & GPTPARTATTR_REQUIRED) {
+			DPRINTF("spoofgpt: Skipping partition %u (REQUIRED)\n");
+			continue;
+		}
+
 		start = letoh64(gp[i].gp_lba_start);
 		if (start > lbaend || start < lbastart)
 			continue;
diff --git a/sys/sys/disklabel.h b/sys/sys/disklabel.h
index bc595f3e826..cff3d005db1 100644
--- a/sys/sys/disklabel.h
+++ b/sys/sys/disklabel.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: disklabel.h,v 1.80 2022/09/06 14:14:44 krw Exp $	*/
+/*	$OpenBSD: disklabel.h,v 1.81 2022/09/11 11:47:55 krw Exp $	*/
 /*	$NetBSD: disklabel.h,v 1.41 1996/05/10 23:07:37 mark Exp $	*/
 
 /*
@@ -340,6 +340,9 @@ struct partinfo {
 				/* ASCII string "EFI PART" encoded as 64-bit */
 #define	GPTREVISION		0x10000		/* GPT header version 1.0 */
 #define	NGPTPARTITIONS		128
+#define	GPTPARTATTR_REQUIRED	(1 << 0)
+#define	GPTPARTATTR_IGNORE	(1 << 1)
+#define	GPTPARTATTR_BOOTABLE	(1 << 2)
 #define	GPTDOSACTIVE		0x2
 #define	GPTMINHDRSIZE		92
 #define	GPTMINPARTSIZE		128
-- 
2.20.1