From 91422384d5915a6f14523b3cec557d730c940c6a Mon Sep 17 00:00:00 2001
From: "Zhang, Chao B" <chao.b.zhang@intel.com>
Date: Wed, 13 Apr 2016 16:25:50 +0800
Subject: [PATCH] SecuritPkg: DxeImageVerificationLib: Fix wrong verification
 logic in DBX & DBT

In image verification, if image verified pass in DBT, still need to verify if it is blocked by any other cert/cert hash from DBX.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Chao Zhang <chao.b.zhang@intel.com>
Reviewed-by: Long Qin <qin.long@intel.com>
Reviewed-by: Dick Wilkins <dick_wilkins@phoenix.com>
---
 .../DxeImageVerificationLib/DxeImageVerificationLib.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
index 4b4d3bf77d..8cedb1bfb0 100644
--- a/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
+++ b/SecurityPkg/Library/DxeImageVerificationLib/DxeImageVerificationLib.c
@@ -12,7 +12,7 @@
   DxeImageVerificationHandler(), HashPeImageByType(), HashPeImage() function will accept
   untrusted PE/COFF image and validate its data structure within this image buffer before use.
 
-Copyright (c) 2009 - 2015, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2009 - 2016, Intel Corporation. All rights reserved.<BR>
 This program and the accompanying materials
 are licensed and made available under the terms and conditions of the BSD License
 which accompanies this distribution.  The full text of the license may be found at
@@ -1457,6 +1457,10 @@ IsForbiddenByDbx (
   for (Index = 0; Index < CertNumber; Index++) {
     CertSize = (UINTN) ReadUnaligned32 ((UINT32 *)CertPtr);
     Cert     = (UINT8 *)CertPtr + sizeof (UINT32);
+    //
+    // Advance CertPtr to the next cert in image signer's cert list
+    //
+    CertPtr = CertPtr + sizeof (UINT32) + CertSize;
 
     if (IsCertHashFoundInDatabase (Cert, CertSize, (EFI_SIGNATURE_LIST *)Data, DataSize, &RevocationTime)) {
       //
@@ -1465,11 +1469,14 @@ IsForbiddenByDbx (
       IsForbidden = TRUE;
       if (PassTimestampCheck (AuthData, AuthDataSize, &RevocationTime)) {
         IsForbidden = FALSE;
+        //
+        // Pass DBT check. Continue to check other certs in image signer's cert list against DBX, DBT
+        //
+        continue;
       }
       goto Done;
     }
 
-    CertPtr = CertPtr + sizeof (UINT32) + CertSize;
   }
 
 Done:
-- 
2.39.2