[PATCH v3 07/11] ShellPkg: acpiview: MADT: Validate global pointers before use

["Krzysztof Koch" <krzysztof.koch@arm.com>]

Check if the MadtInterruptControllerType and
MadtInterruptControllerLength pointers have been successfully updated
before they are used for further table parsing.

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

Notes:
    v3:
    - Rebase on latest master [Krzysztof]

    v1:
    - Test against NULL pointers [Krzysztof]

 ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Madt/MadtParser.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Madt/MadtParser.c b/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Madt/MadtParser.c
index 90bdafea1970db522e8ed96de7c6e986cdaca5ba..438905cb24f58b8b82e8fe61280e72f765d578d8 100644
--- a/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Madt/MadtParser.c
+++ b/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Madt/MadtParser.c
@@ -260,6 +260,19 @@ ParseAcpiMadt (
       PARSER_PARAMS (MadtInterruptControllerHeaderParser)
       );
 
+    // Check if the values used to control the parsing logic have been
+    // successfully read.
+    if ((MadtInterruptControllerType == NULL) ||
+        (MadtInterruptControllerLength == NULL)) {
+      IncrementErrorCount ();
+      Print (
+        L"ERROR: Insufficient remaining table buffer length to read the " \
+          L"Interrupt Controller Structure header. Length = %d.\n",
+        AcpiTableLength - Offset
+        );
+      return;
+    }
+
     // Make sure forward progress is made.
     if (*MadtInterruptControllerLength < 2) {
       IncrementErrorCount ();
--
'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)'