From 9f80be9f16a854e3946568fa92edebe26eb79e78 Mon Sep 17 00:00:00 2001
From: Chris Coulson <chris.coulson@canonical.com>
Date: Sat, 22 Jun 2019 15:37:29 +0100
Subject: [PATCH 38/62] tpm: Define EFI_VARIABLE_DATA_TREE as packed

tpm_measure_variable() calculates VarLogSize by adding the size of VarName
and VarData to the size of EFI_VARIABLE_DATA_TREE, and then subtracting
the size of the UnicodeName and VariableData members. This results in a
calculation that is 5 bytes larger than necessary because it doesn't take
in to account the padding of these members. The effect of this is that
shim measures an additional 5 zero bytes when measuring UEFI variables
(at least on 64-bit architectures).

Byte packing EFI_VARIABLE_DATA_TREE fixes this.

Upstream-commit-id: 7e4d3f1c8c7
---
 tpm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tpm.c b/tpm.c
index 516fb876caa..c0617bb479e 100644
--- a/tpm.c
+++ b/tpm.c
@@ -233,7 +233,7 @@ typedef struct {
 	UINT64 VariableDataLength;
 	CHAR16 UnicodeName[1];
 	INT8 VariableData[1];
-} EFI_VARIABLE_DATA_TREE;
+} __attribute__ ((packed)) EFI_VARIABLE_DATA_TREE;
 
 static BOOLEAN tpm_data_measured(CHAR16 *VarName, EFI_GUID VendorGuid, UINTN VarSize, VOID *VarData)
 {
-- 
2.26.2