Re: [PATCH v1 01/11] ShellPkg: acpiview: FADT: Validate global pointers before use

["Carsey, Jaben" <jaben.carsey@intel.com>]

I think it would be easier to see/review these changes logically if the functional changes (1 and 3) were separate from the refactoring change (2).

Reviewed-by: Jaben Carsey <jaben.carsey@intel.com>

> -----Original Message-----
> From: Krzysztof Koch [mailto:krzysztof.koch@arm.com]
> Sent: Thursday, July 11, 2019 11:53 PM
> To: devel@edk2.groups.io
> Cc: Carsey, Jaben <jaben.carsey@intel.com>; Ni, Ray <ray.ni@intel.com>;
> Gao, Zhichao <zhichao.gao@intel.com>; Sami.Mujawar@arm.com;
> Matteo.Carlini@arm.com; nd@arm.com
> Subject: [PATCH v1 01/11] ShellPkg: acpiview: FADT: Validate global pointers
> before use
> 
> 1. Check if the global pointer have been successfully updated before
> they are later used to control the parsing logic in the FADT acpiview
> parser.
> 
> 2. Remove redundant forward function declarations by repositioning
> blocks of code.
> 
> 3. Allow silencing ACPI table content validation errors which do not
> cause table parsing to fail.
> 
> Signed-off-by: Krzysztof Koch <krzysztof.koch@arm.com>
> ---
> 
> Changes can be seen at:
> https://github.com/KrzysztofKoch1/edk2/commit/49cc41430775fb93205e302
> 590a7d31f080c3952
> 
> Notes:
>     v1:
>     - improve the logic in the parser [Krzysztof]
> 
>  ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Fadt/FadtParser.c
> | 131 ++++++++------------
>  1 file changed, 51 insertions(+), 80 deletions(-)
> 
> diff --git
> a/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Fadt/FadtParser.
> c
> b/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Fadt/FadtParser.
> c
> index
> cee7ee0770433da96d6042d2f5d687903f4b5495..600d3b16d7b22b61c1a1fd21
> ecb93f16c7f8fa1a 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 - 2018, ARM Limited. All rights reserved.
> +  Copyright (c) 2016 - 2019, ARM Limited. All rights reserved.
>    SPDX-License-Identifier: BSD-2-Clause-Patent
> 
>    @par Reference(s):
> @@ -12,6 +12,7 @@
>  #include <Library/UefiLib.h>
>  #include "AcpiParser.h"
>  #include "AcpiTableParser.h"
> +#include "AcpiView.h"
> 
>  // Local variables
>  STATIC CONST UINT32* DsdtAddress;
> @@ -46,7 +47,17 @@ EFIAPI
>  ValidateFirmwareCtrl (
>    IN UINT8* Ptr,
>    IN VOID*  Context
> -  );
> +)
> +{
> +#if defined (MDE_CPU_ARM) || defined (MDE_CPU_AARCH64)
> +  if (*(UINT32*)Ptr != 0) {
> +    IncrementErrorCount ();
> +    Print (
> +      L"\nERROR: Firmware Control must be zero for ARM platforms."
> +    );
> +  }
> +#endif
> +}
> 
>  /**
>    This function validates the X_Firmware Control Field.
> @@ -61,7 +72,17 @@ EFIAPI
>  ValidateXFirmwareCtrl (
>    IN UINT8* Ptr,
>    IN VOID*  Context
> -  );
> +)
> +{
> +#if defined (MDE_CPU_ARM) || defined (MDE_CPU_AARCH64)
> +  if (*(UINT64*)Ptr != 0) {
> +    IncrementErrorCount ();
> +    Print (
> +      L"\nERROR: X Firmware Control must be zero for ARM platforms."
> +    );
> +  }
> +#endif
> +}
> 
>  /**
>    This function validates the flags.
> @@ -76,7 +97,17 @@ EFIAPI
>  ValidateFlags (
>    IN UINT8* Ptr,
>    IN VOID*  Context
> -  );
> +)
> +{
> +#if defined (MDE_CPU_ARM) || defined (MDE_CPU_AARCH64)
> +  if (((*(UINT32*)Ptr) & HW_REDUCED_ACPI) == 0) {
> +    IncrementErrorCount ();
> +    Print (
> +      L"\nERROR: HW_REDUCED_ACPI flag must be set for ARM platforms."
> +    );
> +  }
> +#endif
> +}
> 
>  /**
>    An ACPI_PARSER array describing the ACPI FADT Table.
> @@ -142,81 +173,6 @@ STATIC CONST ACPI_PARSER FadtParser[] = {
>    {L"Hypervisor VendorIdentity", 8, 268, L"%lx", NULL, NULL, NULL, NULL}
>  };
> 
> -/**
> -  This function validates the Firmware Control Field.
> -
> -  @param [in] Ptr     Pointer to the start of the field data.
> -  @param [in] Context Pointer to context specific information e.g. this
> -                      could be a pointer to the ACPI table header.
> -**/
> -STATIC
> -VOID
> -EFIAPI
> -ValidateFirmwareCtrl (
> -  IN UINT8* Ptr,
> -  IN VOID*  Context
> -)
> -{
> -#if defined (MDE_CPU_ARM) || defined (MDE_CPU_AARCH64)
> -  if (*(UINT32*)Ptr != 0) {
> -    IncrementErrorCount ();
> -    Print (
> -      L"\nERROR: Firmware Control must be zero for ARM platforms."
> -    );
> -  }
> -#endif
> -}
> -
> -/**
> -  This function validates the X_Firmware Control Field.
> -
> -  @param [in] Ptr     Pointer to the start of the field data.
> -  @param [in] Context Pointer to context specific information e.g. this
> -                      could be a pointer to the ACPI table header.
> -**/
> -STATIC
> -VOID
> -EFIAPI
> -ValidateXFirmwareCtrl (
> -  IN UINT8* Ptr,
> -  IN VOID*  Context
> -)
> -{
> -#if defined (MDE_CPU_ARM) || defined (MDE_CPU_AARCH64)
> -  if (*(UINT64*)Ptr != 0) {
> -    IncrementErrorCount ();
> -    Print (
> -      L"\nERROR: X Firmware Control must be zero for ARM platforms."
> -    );
> -  }
> -#endif
> -}
> -
> -/**
> -  This function validates the flags.
> -
> -  @param [in] Ptr     Pointer to the start of the field data.
> -  @param [in] Context Pointer to context specific information e.g. this
> -                      could be a pointer to the ACPI table header.
> -**/
> -STATIC
> -VOID
> -EFIAPI
> -ValidateFlags (
> -  IN UINT8* Ptr,
> -  IN VOID*  Context
> -)
> -{
> -#if defined (MDE_CPU_ARM) || defined (MDE_CPU_AARCH64)
> -  if (((*(UINT32*)Ptr) & HW_REDUCED_ACPI) == 0) {
> -    IncrementErrorCount ();
> -    Print (
> -      L"\nERROR: HW_REDUCED_ACPI flag must be set for ARM platforms."
> -    );
> -  }
> -#endif
> -}
> -
>  /**
>    This function parses the ACPI FADT table.
>    This function parses the FADT table and optionally traces the ACPI table
> fields.
> @@ -248,12 +204,27 @@ ParseAcpiFadt (
>      PARSER_PARAMS (FadtParser)
>      );
> 
> +  // Check if the values used to control the parsing logic have been
> +  // successfully read.
> +  if ((DsdtAddress == NULL)       ||
> +      (FadtMinorRevision == NULL) ||
> +      (X_DsdtAddress == NULL)) {
> +    IncrementErrorCount ();
> +    Print (
> +      L"ERROR: Insufficient table length. AcpiTableLength = %d. " \
> +        L"FADT parsing aborted.\n",
> +      AcpiTableLength
> +      );
> +    return;
> +  }
> +
>    if (Trace) {
>      Print (L"\nSummary:\n");
>      PrintFieldName (2, L"FADT Version");
>      Print (L"%d.%d\n",  *AcpiHdrInfo.Revision, *FadtMinorRevision);
> 
> -    if (*GetAcpiXsdtHeaderInfo ()->OemTableId !=
> *AcpiHdrInfo.OemTableId) {
> +    if (GetConsistencyChecking () &&
> +        (*GetAcpiXsdtHeaderInfo ()->OemTableId !=
> *AcpiHdrInfo.OemTableId)) {
>        IncrementErrorCount ();
>        Print (L"ERROR: OEM Table Id does not match with RSDT/XSDT.\n");
>      }
> --
> 'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)'
>