Re: [EXTERNAL] [edk2-devel] [PATCH 1/1] MdeModulePkg/BmpSupportLib: Allow BMP with extra data

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

On 03/23/21 18:41, Bret Barkelew via groups.io wrote:
> Is this a *good* idea?
> 
> What is considered valid extra data? If it’s immaterial to the FW displaying the image, our policy has been to strip it off BEFORE adding it to the FW image.

Not counting any potential security aspects, stripping out undisplayed
portions helps with flash usage too (I think?), so at least some
concrete justification in the commit message would be nice...

Thanks
Laszlo

> 
> - Bret
> 
> From: Jeff Brasen via groups.io<mailto:jbrasen=nvidia.com@groups.io>
> Sent: Tuesday, March 23, 2021 10:29 AM
> To: devel@edk2.groups.io<mailto:devel@edk2.groups.io>
> Cc: jian.j.wang@intel.com<mailto:jian.j.wang@intel.com>; ao.a.wu@intel.com<mailto:ao.a.wu@intel.com>; Jeff Brasen<mailto:jbrasen@nvidia.com>
> Subject: [EXTERNAL] [edk2-devel] [PATCH 1/1] MdeModulePkg/BmpSupportLib: Allow BMP with extra data
> 
> Add support for processing BMP data that contains extra data after the
> image array, this data will not be parsed in anyway in the library but
> images that contain this will not be rejected from processing.
> 
> ---
>  MdeModulePkg/Library/BaseBmpSupportLib/BmpSupportLib.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/MdeModulePkg/Library/BaseBmpSupportLib/BmpSupportLib.c b/MdeModulePkg/Library/BaseBmpSupportLib/BmpSupportLib.c
> index 3ac31f6723d0..944d01fe7cdf 100644
> --- a/MdeModulePkg/Library/BaseBmpSupportLib/BmpSupportLib.c
> +++ b/MdeModulePkg/Library/BaseBmpSupportLib/BmpSupportLib.c
> @@ -213,7 +213,7 @@ TranslateBmpToGopBlt (
> 
>    if ((BmpHeader->Size != BmpImageSize) ||
>        (BmpHeader->Size < BmpHeader->ImageOffset) ||
> -      (BmpHeader->Size - BmpHeader->ImageOffset != DataSize)) {
> +      (BmpHeader->Size - BmpHeader->ImageOffset < DataSize)) {
> 
>      DEBUG ((DEBUG_ERROR, "TranslateBmpToGopBlt: invalid BmpImage... \n"));
>      DEBUG ((DEBUG_ERROR, "   BmpHeader->Size: 0x%x\n", BmpHeader->Size));
> --
> 2.25.1
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
>