ShellPkg: acpiview: GTDT: Validate global pointers before use

Check if global (in the scope of the GTDT parser) 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, 37 insertions, 0 deletions

diff --git a/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Gtdt/GtdtParser.c b/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Gtdt/GtdtParser.c
index 57174e14c8..699a55b549 100644
--- a/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Gtdt/GtdtParser.c
+++ b/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Gtdt/GtdtParser.c
@@ -189,6 +189,18 @@ DumpGTBlock (
     PARSER_PARAMS (GtBlockParser)

     );

 

+  // Check if the values used to control the parsing logic have been

+  // successfully read.

+  if ((GtBlockTimerCount == NULL) ||

+      (GtBlockTimerOffset == NULL)) {

+    IncrementErrorCount ();

+    Print (

+      L"ERROR: Insufficient GT Block Structure length. Length = %d.\n",

+      Length

+      );

+    return;

+  }

+

   Offset = *GtBlockTimerOffset;

   Index = 0;

 

@@ -272,6 +284,18 @@ ParseAcpiGtdt (
     PARSER_PARAMS (GtdtParser)

     );

 

+  // Check if the values used to control the parsing logic have been

+  // successfully read.

+  if ((GtdtPlatformTimerCount == NULL) ||

+      (GtdtPlatformTimerOffset == NULL)) {

+    IncrementErrorCount ();

+    Print (

+      L"ERROR: Insufficient table length. AcpiTableLength = %d.\n",

+      AcpiTableLength

+      );

+    return;

+  }

+

   TimerPtr = Ptr + *GtdtPlatformTimerOffset;

   Offset = *GtdtPlatformTimerOffset;

   Index = 0;

@@ -290,6 +314,19 @@ ParseAcpiGtdt (
       PARSER_PARAMS (GtPlatformTimerHeaderParser)

       );

 

+    // Check if the values used to control the parsing logic have been

+    // successfully read.

+    if ((PlatformTimerType == NULL) ||

+        (PlatformTimerLength == NULL)) {

+      IncrementErrorCount ();

+      Print (

+        L"ERROR: Insufficient remaining table buffer length to read the " \

+          L"Platform Timer Structure header. Length = %d.\n",

+        AcpiTableLength - Offset

+        );

+      return;

+    }

+

     // Make sure the Platform Timer is inside the table.

     if ((Offset + *PlatformTimerLength) > AcpiTableLength) {

       IncrementErrorCount ();