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authorStar Zeng <star.zeng@intel.com>2016-12-09 14:47:03 +0800
committerStar Zeng <star.zeng@intel.com>2016-12-12 09:17:58 +0800
commit62016c1e898434a0326f658912b1e7e0a9c5575e (patch)
tree35c06234081e25086f18c65855a0454c81d4fadd
parent8b78de74dc6a7d655de50f1e203cbc830de1d9ae (diff)
downloadedk2-platforms-62016c1e898434a0326f658912b1e7e0a9c5575e.tar.xz
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 eaae7b33b1cf6b9f21db1636f219c2b6a8d88afd, 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 eaae7b33b1cf6b9f21db1636f219c2b6a8d88afd. Before eaae7b33b1cf6b9f21db1636f219c2b6a8d88afd, CommBufferSize buffer pointed to gSmmCorePrivate->BufferSize that is outside SMRAM, the check will success definitely; after eaae7b33b1cf6b9f21db1636f219c2b6a8d88afd, 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>
-rw-r--r--MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c9
1 files changed, 4 insertions, 5 deletions
diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c
index eafb53322e..c714916019 100644
--- a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c
+++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableSmm.c
@@ -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;