From e4f6a1bfa31a2299612bbf9dae402bb38d38b1df Mon Sep 17 00:00:00 2001
From: Toomas Soome <tsoome@FreeBSD.org>
Date: Fri, 1 Dec 2017 06:37:12 +0000
Subject: [PATCH] loader.efi: efipart should exclude iPXE stub block protocol

iPXE does insert stub  BLOCK IO protocol handle to rework other issues,
this handle is not usable as it does not provide actual implementation.

We can detect this situation by checking and validating the BlockSize
property, so this update does make sure we have BlockSize at least 512B
and its value is power of 2.

PR:		223969
Reported by:	Jeff Pieper
Reviewed by:	imp
Differential Revision:	https://reviews.freebsd.org/D13297
---
 stand/efi/libefi/efipart.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/stand/efi/libefi/efipart.c b/stand/efi/libefi/efipart.c
index 1e161c2bb39..a5a1a822060 100644
--- a/stand/efi/libefi/efipart.c
+++ b/stand/efi/libefi/efipart.c
@@ -257,6 +257,14 @@ efipart_hdd(EFI_DEVICE_PATH *dp)
 		    !blkio->Media->MediaPresent) {
 			return (false);
 		}
+
+		/*
+		 * We assume the block size 512 or greater power of 2. 
+		 */
+		if (blkio->Media->BlockSize < 512 ||
+		    !powerof2(blkio->Media->BlockSize)) {
+			return (false);
+		}
 	}
 	return (true);
 }