From 73de814a5f30c2c6d82736082c1114a028d12115 Mon Sep 17 00:00:00 2001
From: Laszlo Ersek <lersek@redhat.com>
Date: Fri, 31 Jan 2020 12:42:41 +0100
Subject: [PATCH 05/12] SecurityPkg/DxeImageVerificationHandler: narrow down
 PE/COFF hash status
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RH-Author: Laszlo Ersek <lersek@redhat.com>
Message-id: <20200131124248.22369-6-lersek@redhat.com>
Patchwork-id: 93615
O-Subject: [RHEL-8.2.0 edk2 PATCH 05/12] SecurityPkg/DxeImageVerificationHandler: narrow down PE/COFF hash status
Bugzilla: 1751993
RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>
RH-Acked-by: Vitaly Kuznetsov <vkuznets@redhat.com>

Inside the "for" loop that scans the signatures of the image, we call
HashPeImageByType(), and assign its return value to "Status".

Beyond the immediate retval check, this assignment is useless (never
consumed). That's because a subsequent access to "Status" may only be one
of the following:

- the "Status" assignment when we call HashPeImageByType() in the next
  iteration of the loop,

- the "Status = EFI_ACCESS_DENIED" assignment right after the final
  "IsVerified" check.

To make it clear that the assignment is only useful for the immediate
HashPeImageByType() retval check, introduce a specific helper variable,
called "HashStatus".

This patch is a no-op, functionally.

Cc: Chao Zhang <chao.b.zhang@intel.com>
Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2129
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20200116190705.18816-5-lersek@redhat.com>
Reviewed-by: Michael D Kinney <michael.d.kinney@intel.com>
[lersek@redhat.com: push with Mike's R-b due to Chinese New Year
 Holiday: <https://edk2.groups.io/g/devel/message/53429>; msgid
 <d3fbb76dabed4e1987c512c328c82810@intel.com>]
(cherry picked from commit 47650a5cab608e07c31d66bdb9b4cc6e58bdf22f)

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 .../Library/DxeImageVerificationLib/DxeImageVerificationLib.c        | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
index e6c8a54..5cc82c1 100644
--- a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
+++ b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
@@ -1581,6 +1581,7 @@ DxeImageVerificationHandler (
   UINT32                               OffSet;
   CHAR16                               *NameStr;
   RETURN_STATUS                        PeCoffStatus;
+  EFI_STATUS                           HashStatus;
 
   SignatureList     = NULL;
   SignatureListSize = 0;
@@ -1802,8 +1803,8 @@ DxeImageVerificationHandler (
       continue;
     }
 
-    Status = HashPeImageByType (AuthData, AuthDataSize);
-    if (EFI_ERROR (Status)) {
+    HashStatus = HashPeImageByType (AuthData, AuthDataSize);
+    if (EFI_ERROR (HashStatus)) {
       continue;
     }
 
-- 
1.8.3.1