+ @Liming Gao

- Bret

From: Bret Barkelew via groups.io
Sent: Friday, April 9, 2021 11:25 AM
To: devel@edk2.groups.io
Cc: Jian J Wang; Hao A Wu
Subject: [EXTERNAL] [edk2-devel] [PATCH v1 1/1] MdeModulePkg: Initialize temp variable in VarCheckPolicyLib

DumpVariablePolicy() will return EFI_INVALID_PARAMETER if the Buffer
pointer is NULL and the indirect Size is anything but 0. Since this
TempSize was not being initialized it is very likely that this sequence
would not return the total buffer size as expected.

Bugzilla: https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbugzilla.tianocore.org%2Fshow_bug.cgi%3Fid%3D3310&data=04%7C01%7CBret.Barkelew%40microsoft.com%7C3d2f574a01a048aed60708d8fb84dcbb%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C637535895350828079%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=j6KmN6jcwoGJlunjspLawLJtYqCwGWw18pXNZVMNdC8%3D&reserved=0

Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Signed-off-by: Bret Barkelew <bret.barkelew@microsoft.com>
---
 MdeModulePkg/Library/VarCheckPolicyLib/VarCheckPolicyLib.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/MdeModulePkg/Library/VarCheckPolicyLib/VarCheckPolicyLib.c b/MdeModulePkg/Library/VarCheckPolicyLib/VarCheckPolicyLib.c
index 14e1904e96d3..e50edb4ffc5a 100644
--- a/MdeModulePkg/Library/VarCheckPolicyLib/VarCheckPolicyLib.c
+++ b/MdeModulePkg/Library/VarCheckPolicyLib/VarCheckPolicyLib.c
@@ -216,6 +216,7 @@ VarCheckPolicyLibMmiHandler (
         DumpParamsOut->TotalSize = 0;
         DumpParamsOut->PageSize = 0;
         DumpParamsOut->HasMore = FALSE;
+        TempSize = 0;
         SubCommandStatus = DumpVariablePolicy (NULL, &TempSize);
         if (SubCommandStatus == EFI_BUFFER_TOO_SMALL && TempSize > 0) {
           mCurrentPaginationCommand = VAR_CHECK_POLICY_COMMAND_DUMP;
--
2.28.0.windows.1