ShellPkg: acpiview: FADT: Validate global pointer before use

Check if global pointers have been successfully updated before they
are used for further table parsing.

Signed-off-by: Krzysztof Koch <krzysztof.koch@arm.com>

1 files changed, 11 insertions, 10 deletions

diff --git a/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Fadt/FadtParser.c b/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Fadt/FadtParser.c
index 8acfbac3b1..d86718bab6 100644
--- a/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Fadt/FadtParser.c
+++ b/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Fadt/FadtParser.c
@@ -1,7 +1,7 @@
 /** @file

   FADT table parser

 

-  Copyright (c) 2016 - 2019, ARM Limited. All rights reserved.

+  Copyright (c) 2016 - 2020, ARM Limited. All rights reserved.

   SPDX-License-Identifier: BSD-2-Clause-Patent

 

   @par Reference(s):

@@ -230,9 +230,11 @@ ParseAcpiFadt (
     );

 

   if (Trace) {

-    Print (L"\nSummary:\n");

-    PrintFieldName (2, L"FADT Version");

-    Print (L"%d.%d\n",  *AcpiHdrInfo.Revision, *FadtMinorRevision);

+    if (FadtMinorRevision != NULL) {

+      Print (L"\nSummary:\n");

+      PrintFieldName (2, L"FADT Version");

+      Print (L"%d.%d\n",  *AcpiHdrInfo.Revision, *FadtMinorRevision);

+    }

 

     if (*GetAcpiXsdtHeaderInfo ()->OemTableId != *AcpiHdrInfo.OemTableId) {

       IncrementErrorCount ();

@@ -294,21 +296,20 @@ ParseAcpiFadt (
       );

   }

 

-  // If X_DSDT is not zero then use X_DSDT and ignore DSDT,

-  // else use DSDT.

-  if (*X_DsdtAddress != 0) {

+  // If X_DSDT is valid then use X_DSDT and ignore DSDT, else use DSDT.

+  if ((X_DsdtAddress != NULL) && (*X_DsdtAddress != 0)) {

     DsdtPtr = (UINT8*)(UINTN)(*X_DsdtAddress);

-  } else if (*DsdtAddress != 0) {

+  } else if ((DsdtAddress != NULL) && (*DsdtAddress != 0)) {

     DsdtPtr = (UINT8*)(UINTN)(*DsdtAddress);

   } else {

-    // Both DSDT and X_DSDT cannot be zero.

+    // Both DSDT and X_DSDT cannot be invalid.

 #if defined (MDE_CPU_ARM) || defined (MDE_CPU_AARCH64)

     if (Trace) {

       // The DSDT Table is mandatory for ARM systems

       // as the CPU information MUST be presented in

       // the DSDT.

       IncrementErrorCount ();

-      Print (L"ERROR: Both X_DSDT and DSDT are NULL.\n");

+      Print (L"ERROR: Both X_DSDT and DSDT are invalid.\n");

     }

 #endif

     return;