Re: [edk2-devel] [PATCH v4 3/4] StandaloneMmPkg/Core: Fix issue that offset calculation might be wrong

["Laszlo Ersek" <lersek@redhat.com>]

On 11/6/23 08:52, Xu, Wei6 wrote:
> MmCoreFfsFindMmDriver() assumes FileHeader is EFI_FFS_FILE_HEADER.
> If FileHeader is an EFI_FFS_FILE_HEADER2, 'FileHeader + 1' will get a
> wrong section address. Use FfsFindSection to get the section directly,
> instead of 'FileHeader + 1' to avoid this issue.
> MmCoreFfsFindMmDriver() also assumes section is EFI_COMMON_SECTION_HEADER.
> If Section is EFI_COMMON_SECTION_HEADER2, 'Section + 1' will get a wrong
> wrong InnerFvHeader adress. Add section head detection and calculate the
> address accordingly.
> 
> Cc: Laszlo Ersek <lersek@redhat.com>
> Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
> Cc: Sami Mujawar <sami.mujawar@arm.com>
> Cc: Ray Ni <ray.ni@intel.com>
> Signed-off-by: Wei6 Xu <wei6.xu@intel.com>
> ---
>  StandaloneMmPkg/Core/FwVol.c | 29 +++++++++++++++--------------
>  1 file changed, 15 insertions(+), 14 deletions(-)
> 
> diff --git a/StandaloneMmPkg/Core/FwVol.c b/StandaloneMmPkg/Core/FwVol.c
> index c3054ef751ed..4d2b63a448e7 100644
> --- a/StandaloneMmPkg/Core/FwVol.c
> +++ b/StandaloneMmPkg/Core/FwVol.c
> @@ -79,8 +79,6 @@ MmCoreFfsFindMmDriver (
>    UINTN                       DepexSize;
>    UINTN                       Index;
>    EFI_COMMON_SECTION_HEADER   *Section;
> -  VOID                        *SectionData;
> -  UINTN                       SectionDataSize;
>    UINT32                      DstBufferSize;
>    VOID                        *ScratchBuffer;
>    UINT32                      ScratchBufferSize;
> @@ -117,23 +115,21 @@ MmCoreFfsFindMmDriver (
>        break;
>      }
>  
> -    Status = FfsFindSectionData (
> +    Status = FfsFindSection (
>                 EFI_SECTION_GUID_DEFINED,
>                 FileHeader,
> -               &SectionData,
> -               &SectionDataSize
> +               &Section
>                 );
>      if (EFI_ERROR (Status)) {
>        break;
>      }
>  
> -    Section = (EFI_COMMON_SECTION_HEADER *)(FileHeader + 1);
> -    Status  = ExtractGuidedSectionGetInfo (
> -                Section,
> -                &DstBufferSize,
> -                &ScratchBufferSize,
> -                &SectionAttribute
> -                );
> +    Status = ExtractGuidedSectionGetInfo (
> +               Section,
> +               &DstBufferSize,
> +               &ScratchBufferSize,
> +               &SectionAttribute
> +               );
>      if (EFI_ERROR (Status)) {
>        break;
>      }
> @@ -194,8 +190,13 @@ MmCoreFfsFindMmDriver (
>        goto FreeDstBuffer;
>      }
>  
> -    InnerFvHeader = (VOID *)(Section + 1);
> -    Status        = MmCoreFfsFindMmDriver (InnerFvHeader, Depth + 1);
> +    if (IS_SECTION2 (Section)) {
> +      InnerFvHeader = (VOID *)((EFI_COMMON_SECTION_HEADER2 *)Section + 1);
> +    } else {
> +      InnerFvHeader = (VOID *)(Section + 1);
> +    }
> +
> +    Status = MmCoreFfsFindMmDriver (InnerFvHeader, Depth + 1);
>      if (EFI_ERROR (Status)) {
>        goto FreeDstBuffer;
>      }

Reviewed-by: Laszlo Ersek <lersek@redhat.com>



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