Enhance TPM driver to protect TPM physical presence flags.

[mirror_edk2.git] / SecurityPkg / Tcg / TcgSmm / TcgSmm.c

diff --git a/SecurityPkg/Tcg/TcgSmm/TcgSmm.c b/SecurityPkg/Tcg/TcgSmm/TcgSmm.c
index dd6d89f695fc7310a1279a90c8f75210f364f234..97cd916d0711f5d1768e946b48e48e621e3c667e 100644 (file)
--- a/SecurityPkg/Tcg/TcgSmm/TcgSmm.c
+++ b/SecurityPkg/Tcg/TcgSmm/TcgSmm.c
@@ -2,7 +2,13 @@
   It updates TPM items in ACPI table and registers SMI callback\r
   functions for physical presence and ClearMemory.\r
 \r
-Copyright (c) 2011 - 2012, Intel Corporation. All rights reserved.<BR>\r
+  Caution: This module requires additional review when modified.\r
+  This driver will have external input - variable and ACPINvs data in SMM mode.\r
+  This external input must be validated carefully to avoid security issue.\r
+\r
+  PhysicalPresenceCallback() and MemoryClearCallback() will receive untrusted input and do some check.\r
+\r
+Copyright (c) 2011 - 2013, Intel Corporation. All rights reserved.<BR>\r
 This program and the accompanying materials \r
 are licensed and made available under the terms and conditions of the BSD License \r
 which accompanies this distribution.  The full text of the license may be found at \r
@@ -21,6 +27,10 @@ TCG_NVS                    *mTcgNvs;
 /**\r
   Software SMI callback for TPM physical presence which is called from ACPI method.\r
 \r
+  Caution: This function may receive untrusted input.\r
+  Variable and ACPINvs are external input, so this function will validate\r
+  its data structure to be valid value.\r
+\r
   @param[in]      DispatchHandle  The unique handle assigned to this handler by SmiHandlerRegister().\r
   @param[in]      Context         Points to an optional handler context which was specified when the\r
                                   handler was registered.\r
@@ -93,7 +103,22 @@ PhysicalPresenceCallback (
     }\r
     mTcgNvs->PhysicalPresence.ReturnCode = PP_SUBMIT_REQUEST_SUCCESS;\r
   } else if (mTcgNvs->PhysicalPresence.Parameter == ACPI_FUNCTION_GET_USER_CONFIRMATION_STATUS_FOR_REQUEST) {\r
-    Flags = PpData.Flags;  \r
+    //\r
+    // Get the Physical Presence flags\r
+    //\r
+    DataSize = sizeof (UINT8);\r
+    Status = mSmmVariable->SmmGetVariable (\r
+                             PHYSICAL_PRESENCE_FLAGS_VARIABLE,\r
+                             &gEfiPhysicalPresenceGuid,\r
+                             NULL,\r
+                             &DataSize,\r
+                             &Flags\r
+                             );\r
+    if (EFI_ERROR (Status)) {\r
+      mTcgNvs->PhysicalPresence.ReturnCode = PP_SUBMIT_REQUEST_GENERAL_FAILURE;\r
+      return EFI_SUCCESS;\r
+    }\r
+\r
     RequestConfirmed = FALSE;\r
 \r
     switch (mTcgNvs->PhysicalPresence.Request) {\r
@@ -161,6 +186,10 @@ PhysicalPresenceCallback (
 /**\r
   Software SMI callback for MemoryClear which is called from ACPI method.\r
 \r
+  Caution: This function may receive untrusted input.\r
+  Variable and ACPINvs are external input, so this function will validate\r
+  its data structure to be valid value.\r
+\r
   @param[in]      DispatchHandle  The unique handle assigned to this handler by SmiHandlerRegister().\r
   @param[in]      Context         Points to an optional handler context which was specified when the\r
                                   handler was registered.\r
@@ -295,6 +324,20 @@ PublishAcpiTable (
              );\r
   ASSERT_EFI_ERROR (Status);\r
 \r
+\r
+  //\r
+  // Measure to PCR[0] with event EV_POST_CODE ACPI DATA\r
+  //\r
+  TpmMeasureAndLogData(\r
+    0,\r
+    EV_POST_CODE,\r
+    EV_POSTCODE_INFO_ACPI_DATA,\r
+    ACPI_DATA_LEN,\r
+    Table,\r
+    TableSize\r
+    );\r
+\r
+\r
   ASSERT (Table->OemTableId == SIGNATURE_64 ('T', 'c', 'g', 'T', 'a', 'b', 'l', 'e'));\r
   mTcgNvs = AssignOpRegion (Table, SIGNATURE_32 ('T', 'N', 'V', 'S'), (UINT16) sizeof (TCG_NVS));\r
   ASSERT (mTcgNvs != NULL);\r