tyler.durden
/
audk
mirror of https://github.com/acidanthera/audk.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

MdeModulePkg VariableSmm: Do not need check CommBufferSize buffer 

Current code in SmmVariableHandler() checks CommBufferSize
buffer to make sure it points to outside SMRAM in
"case SMM_VARIABLE_FUNCTION_GET_STATISTICS".

But after eaae7b33b1,
CommBufferSize buffer points to SMRAM that was used by
SMM core to cache CommSize from SmmCommunication protocol,
then the check will fail definitely and GET_STATISTICS
feature breaks.

In fact, do not need check CommBufferSize buffer at all
even before eaae7b33b1.
Before eaae7b33b1,
CommBufferSize buffer pointed to gSmmCorePrivate->BufferSize
that is outside SMRAM, the check will success definitely;
after eaae7b33b1,
CommBufferSize buffer points to local variable BufferSize
(in SMRAM) in SmmEntryPoint(), the check is not needed
definitely.

The patch is to remove the check.

Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Jeff Fan <jeff.fan@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
This commit is contained in:
Star Zeng 2016-12-09 14:47:03 +08:00
parent 8b78de74dc
commit 62016c1e89
1 changed files with 4 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c
View File

@ -695,11 +695,10 @@ SmmVariableHandler (
// It is covered by previous CommBuffer check
//
if (!SmmIsBufferOutsideSmmValid ((EFI_PHYSICAL_ADDRESS)(UINTN)CommBufferSize, sizeof(UINTN))) {
DEBUG ((EFI_D_ERROR, "GetStatistics: SMM communication buffer in SMRAM!\n"));
Status = EFI_ACCESS_DENIED;
goto EXIT;
}
//
// Do not need to check CommBufferSize buffer as it should point to SMRAM
// that was used by SMM core to cache CommSize from SmmCommunication protocol.
//
Status = SmmVariableGetStatistics (VariableInfo, &InfoSize);
*CommBufferSize = InfoSize + SMM_VARIABLE_COMMUNICATE_HEADER_SIZE;