SecurityPkg Variable: Reuse scratch data area(at the end of volatile variable store)

as serialization runtime buffer to reduce SMRAM consumption for SMM variable driver.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Guo Dong <guo.dong@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@17059 6f19259b-4bc3-4df7-8a09-765794883524

4 files changed, 29 insertions, 21 deletions

diff --git a/SecurityPkg/VariableAuthenticated/RuntimeDxe/AuthService.c b/SecurityPkg/VariableAuthenticated/RuntimeDxe/AuthService.c
index 9b8f63f089..1e9e1907c0 100644
--- a/SecurityPkg/VariableAuthenticated/RuntimeDxe/AuthService.c
+++ b/SecurityPkg/VariableAuthenticated/RuntimeDxe/AuthService.c
@@ -56,14 +56,6 @@ CONST UINT8 mRsaE[] = { 0x01, 0x00, 0x01 };
 VOID  *mHashCtx = NULL;

 

 //

-// The serialization of the values of the VariableName, VendorGuid and Attributes

-// parameters of the SetVariable() call and the TimeStamp component of the

-// EFI_VARIABLE_AUTHENTICATION_2 descriptor followed by the variable's new value

-// i.e. (VariableName, VendorGuid, Attributes, TimeStamp, Data)

-//

-UINT8 *mSerializationRuntimeBuffer = NULL;

-

-//

 // Requirement for different signature type which have been defined in UEFI spec.

 // These data are used to peform SignatureList format check while setting PK/KEK variable.

 //

@@ -183,15 +175,6 @@ AutenticatedVariableServiceInitialize (
   }

 

   //

-  // Prepare runtime buffer for serialized data of time-based authenticated

-  // Variable, i.e. (VariableName, VendorGuid, Attributes, TimeStamp, Data).

-  //

-  mSerializationRuntimeBuffer = AllocateRuntimePool (PcdGet32 (PcdMaxVariableSize) + sizeof (EFI_GUID) + sizeof (UINT32) + sizeof (EFI_TIME));

-  if (mSerializationRuntimeBuffer == NULL) {

-    return EFI_OUT_OF_RESOURCES;

-  }

-

-  //

   // Check "AuthVarKeyDatabase" variable's existence.

   // If it doesn't exist, create a new one with initial value of 0 and EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS set.

   //

@@ -2267,11 +2250,21 @@ VerifyTimeBasedPayload (
   PayloadSize = DataSize - OFFSET_OF_AUTHINFO2_CERT_DATA - (UINTN) SigDataSize;

 

   //

-  // Construct a buffer to fill with (VariableName, VendorGuid, Attributes, TimeStamp, Data).

+  // Construct a serialization buffer of the values of the VariableName, VendorGuid and Attributes

+  // parameters of the SetVariable() call and the TimeStamp component of the

+  // EFI_VARIABLE_AUTHENTICATION_2 descriptor followed by the variable's new value

+  // i.e. (VariableName, VendorGuid, Attributes, TimeStamp, Data)

   //

   NewDataSize = PayloadSize + sizeof (EFI_TIME) + sizeof (UINT32) +

                 sizeof (EFI_GUID) + StrSize (VariableName) - sizeof (CHAR16);

-  NewData = mSerializationRuntimeBuffer;

+  //

+  // Here is to reuse scratch data area(at the end of volatile variable store)

+  // to reduce SMRAM consumption for SMM variable driver.

+  // The scratch buffer is enough to hold the serialized data and safe to use,

+  // because it will be used at here to do verification only first

+  // and then used in UpdateVariable() for a time based auth variable set.

+  //

+  NewData = (UINT8 *) GetEndPointer ((VARIABLE_STORE_HEADER *) ((UINTN) mVariableModuleGlobal->VariableGlobal.VolatileVariableBase));

 

   Buffer = NewData;

   Length = StrLen (VariableName) * sizeof (CHAR16);

diff --git a/SecurityPkg/VariableAuthenticated/RuntimeDxe/AuthService.h b/SecurityPkg/VariableAuthenticated/RuntimeDxe/AuthService.h
index e0804f4e34..f28c82578e 100644
--- a/SecurityPkg/VariableAuthenticated/RuntimeDxe/AuthService.h
+++ b/SecurityPkg/VariableAuthenticated/RuntimeDxe/AuthService.h
@@ -351,6 +351,5 @@ extern UINT8  *mPubKeyStore;
 extern UINT8  *mCertDbStore;

 extern UINT32 mPubKeyNumber;

 extern VOID   *mHashCtx;

-extern UINT8  *mSerializationRuntimeBuffer;

 

 #endif

diff --git a/SecurityPkg/VariableAuthenticated/RuntimeDxe/Variable.h b/SecurityPkg/VariableAuthenticated/RuntimeDxe/Variable.h
index f86b202fda..fd4dab2429 100644
--- a/SecurityPkg/VariableAuthenticated/RuntimeDxe/Variable.h
+++ b/SecurityPkg/VariableAuthenticated/RuntimeDxe/Variable.h
@@ -196,6 +196,23 @@ FindVariable (
 

 /**

 

+  Gets the pointer to the end of the variable storage area.

+

+  This function gets pointer to the end of the variable storage

+  area, according to the input variable store header.

+

+  @param VarStoreHeader  Pointer to the Variable Store Header.

+

+  @return Pointer to the end of the variable storage area.

+

+**/

+VARIABLE_HEADER *

+GetEndPointer (

+  IN VARIABLE_STORE_HEADER       *VarStoreHeader

+  );

+

+/**

+

   This code gets the pointer to the variable data.

 

   @param Variable        Pointer to the Variable Header.

diff --git a/SecurityPkg/VariableAuthenticated/RuntimeDxe/VariableDxe.c b/SecurityPkg/VariableAuthenticated/RuntimeDxe/VariableDxe.c
index 05a90fa8fc..f5bb9963e0 100644
--- a/SecurityPkg/VariableAuthenticated/RuntimeDxe/VariableDxe.c
+++ b/SecurityPkg/VariableAuthenticated/RuntimeDxe/VariableDxe.c
@@ -247,7 +247,6 @@ VariableClassAddressChangeEvent (
   EfiConvertPointer (0x0, (VOID **) &mVariableModuleGlobal->VariableGlobal.HobVariableBase);

   EfiConvertPointer (0x0, (VOID **) &mVariableModuleGlobal);

   EfiConvertPointer (0x0, (VOID **) &mHashCtx);

-  EfiConvertPointer (0x0, (VOID **) &mSerializationRuntimeBuffer);

   EfiConvertPointer (0x0, (VOID **) &mNvVariableCache);

   EfiConvertPointer (0x0, (VOID **) &mPubKeyStore);

   EfiConvertPointer (0x0, (VOID **) &mCertDbStore);