Re: [PATCH v2] SecurityPkg/SecureBootConfigDxe: Fix deleting signature data issue.

["Zhang, Chao B" <chao.b.zhang@intel.com>]

Reviewed-by: Chao Zhang <chao.b.zhang@intel.com>

-----Original Message-----
From: Chen, Chen A 
Sent: Monday, November 27, 2017 10:03 AM
To: edk2-devel@lists.01.org
Cc: Chen, Chen A <chen.a.chen@intel.com>; Zhang, Chao B <chao.b.zhang@intel.com>
Subject: [PATCH v2] SecurityPkg/SecureBootConfigDxe: Fix deleting signature data issue.

Replace "(UINT8 *)NewVariableData" with (UINT8 *)NewVariableData + Offset"
to avoid the header of EFI_SIGNATURE_LIST being copied to the front of NewVariableData every time and update ListWalker when handling the current EFI_SIGNATURE_LIST finishes.

Cc: Zhang Chao <chao.b.zhang@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: chenc2 <chen.a.chen@intel.com>
---
 .../SecureBootConfigDxe/SecureBootConfigImpl.c       | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigImpl.c b/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigImpl.c
index d035763106..e3066f77be 100644
--- a/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootConfigImpl.c
+++ b/SecurityPkg/VariableAuthenticated/SecureBootConfigDxe/SecureBootCo
+++ nfigImpl.c
@@ -3145,6 +3145,9 @@ DeleteSignatureEx (
   if (DelType == Delete_Signature_List_All) {
     VariableDataSize = 0;
   } else {
+    //
+    //  Traverse to target EFI_SIGNATURE_LIST but others will be skipped.
+    //
     while ((RemainingSize > 0) && (RemainingSize >= ListWalker->SignatureListSize) && ListIndex < PrivateData->ListIndex) {
       CopyMem ((UINT8 *)NewVariableData + Offset, ListWalker, ListWalker->SignatureListSize);
       Offset += ListWalker->SignatureListSize; @@ -3154,15 +3157,17 @@ DeleteSignatureEx (
       ListIndex++;
     }
 
-    if (CheckedCount == SIGNATURE_DATA_COUNTS (ListWalker) || DelType == Delete_Signature_List_One) {
-      RemainingSize -= ListWalker->SignatureListSize;
-      ListWalker = (EFI_SIGNATURE_LIST *)((UINT8 *)ListWalker + ListWalker->SignatureListSize);
-    } else {
+    //
+    //  Handle the target EFI_SIGNATURE_LIST.
+    //  If CheckedCount == SIGNATURE_DATA_COUNTS (ListWalker) or DelType == Delete_Signature_List_One
+    //  it means delete the whole EFI_SIGNATURE_LIST, So we just skip this EFI_SIGNATURE_LIST.
+    //
+    if (CheckedCount < SIGNATURE_DATA_COUNTS (ListWalker) && DelType == 
+ Delete_Signature_Data) {
       NewCertList = (EFI_SIGNATURE_LIST *)(NewVariableData + Offset);
       //
       // Copy header.
       //
-      CopyMem ((UINT8 *)NewVariableData, ListWalker, sizeof (EFI_SIGNATURE_LIST) + ListWalker->SignatureHeaderSize);
+      CopyMem ((UINT8 *)NewVariableData + Offset, ListWalker, sizeof 
+ (EFI_SIGNATURE_LIST) + ListWalker->SignatureHeaderSize);
       Offset += sizeof (EFI_SIGNATURE_LIST) + ListWalker->SignatureHeaderSize;
 
       DataWalker = (EFI_SIGNATURE_DATA *)((UINT8 *)ListWalker + sizeof(EFI_SIGNATURE_LIST) + ListWalker->SignatureHeaderSize); @@ -3181,10 +3186,11 @@ DeleteSignatureEx (
         }
         DataWalker = (EFI_SIGNATURE_DATA *)((UINT8 *)DataWalker + ListWalker->SignatureSize);
       }
-
-      RemainingSize -= ListWalker->SignatureListSize;
     }
 
+    RemainingSize -= ListWalker->SignatureListSize;
+    ListWalker = (EFI_SIGNATURE_LIST *)((UINT8 *)ListWalker + 
+ ListWalker->SignatureListSize);
+
     //
     // Copy remaining data, maybe 0.
     //
--
2.13.2.windows.1