[PATCH v1 1/1] MdeModulePkg/Variable: TcgMorLockSmm Key Mismatch changes lock state

["Abhimanyu Singh" <Abhi.Singh@arm.com>]

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4410

Inside TcgMorLockSmm.c, the SetVariableCheckHandlerMorLock() function
contains a scenario to prevent a possible dictionary attack on the MorLock
Key in accordance with the TCG Platform Reset Mitigation Spec v1.10.

The mechanism to prevent this attack must also change the MorLock Variable
Value to 0x01 to indicate Locked Without Key.

Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Signed-off-by: Abhi Singh <Abhi.Singh@arm.com>
---
 MdeModulePkg/Universal/Variable/RuntimeDxe/TcgMorLockSmm.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/TcgMorLockSmm.c b/MdeModulePkg/Universal/Variable/RuntimeDxe/TcgMorLockSmm.c
index da1105ff073e..a76db18ef877 100644
--- a/MdeModulePkg/Universal/Variable/RuntimeDxe/TcgMorLockSmm.c
+++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/TcgMorLockSmm.c
@@ -312,6 +312,10 @@ SetVariableCheckHandlerMorLock (
       mMorLockState    = MorLockStateLocked;
       mMorLockKeyEmpty = TRUE;
       ZeroMem (mMorLockKey, sizeof (mMorLockKey));
+      //
+      // Update value to reflect locked without key
+      //
+      SetMorLockVariable (MOR_LOCK_DATA_LOCKED_WITHOUT_KEY);
       return EFI_ACCESS_DENIED;
     }
   }
-- 
2.34.1