1 files changed, 14 insertions, 0 deletions
diff --git a/SecurityPkg/Tcg/TcgSmm/TcgSmm.c b/SecurityPkg/Tcg/TcgSmm/TcgSmm.c
index dd6d89f695..6fa383d46d 100644
--- a/SecurityPkg/Tcg/TcgSmm/TcgSmm.c
+++ b/SecurityPkg/Tcg/TcgSmm/TcgSmm.c
@@ -2,6 +2,12 @@
   It updates TPM items in ACPI table and registers SMI callback
   functions for physical presence and ClearMemory.
 
+  Caution: This module requires additional review when modified.
+  This driver will have external input - variable and ACPINvs data in SMM mode.
+  This external input must be validated carefully to avoid security issue.
+
+  PhysicalPresenceCallback() and MemoryClearCallback() will receive untrusted input and do some check.
+
 Copyright (c) 2011 - 2012, Intel Corporation. All rights reserved.<BR>
 This program and the accompanying materials 
 are licensed and made available under the terms and conditions of the BSD License 
@@ -21,6 +27,10 @@ TCG_NVS                    *mTcgNvs;
 /**
   Software SMI callback for TPM physical presence which is called from ACPI method.
 
+  Caution: This function may receive untrusted input.
+  Variable and ACPINvs are external input, so this function will validate
+  its data structure to be valid value.
+
   @param[in]      DispatchHandle  The unique handle assigned to this handler by SmiHandlerRegister().
   @param[in]      Context         Points to an optional handler context which was specified when the
                                   handler was registered.
@@ -161,6 +171,10 @@ PhysicalPresenceCallback (
 /**
   Software SMI callback for MemoryClear which is called from ACPI method.
 
+  Caution: This function may receive untrusted input.
+  Variable and ACPINvs are external input, so this function will validate
+  its data structure to be valid value.
+
   @param[in]      DispatchHandle  The unique handle assigned to this handler by SmiHandlerRegister().
   @param[in]      Context         Points to an optional handler context which was specified when the
                                   handler was registered.