Re: [edk2-devel] [PATCH 1/1] SignedCapsulePkg: Add handling of NULL returned from FMP Descriptor

["Ard Biesheuvel" <ard.biesheuvel@arm.com>]

On 5/6/20 10:54 AM, Gaurav Jain via groups.io wrote:
> Firmware management protocol that does not support GetImageInfo
> return Unsupported.

The UEFI spec does not list EFI_UNSUPPORTED as a permitted return value 
for EFI_FIRMWARE_MANAGEMENT_PROTOCOL.GetImageInfo()

What is the point of producing the protocol in this case?

> hence FMP Image Information Buffer is NULL.
> Freeing NULL buffer results in Exception.
> 
> Added NULL check for Image Info buffer
> and skip processing FMP protocol handle,
> which does not support GetImageInfo.
> 
> Signed-off-by: Gaurav Jain <gaurav.jain@nxp.com>
> ---
>   .../Universal/SystemFirmwareUpdate/SystemFirmwareUpdateDxe.c         | 5 ++++-
>   1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/SignedCapsulePkg/Universal/SystemFirmwareUpdate/SystemFirmwareUpdateDxe.c b/SignedCapsulePkg/Universal/SystemFirmwareUpdate/SystemFirmwareUpdateDxe.c
> index bdb70bdb32cc..b4438ac6f55a 100644
> --- a/SignedCapsulePkg/Universal/SystemFirmwareUpdate/SystemFirmwareUpdateDxe.c
> +++ b/SignedCapsulePkg/Universal/SystemFirmwareUpdate/SystemFirmwareUpdateDxe.c
> @@ -579,7 +579,7 @@ GetFmpImageDescriptors (
>                     &PackageVersionName          // PackageVersionName
>                     );
>     if (Status != EFI_BUFFER_TOO_SMALL) {
> -    DEBUG ((DEBUG_ERROR, "SystemFirmwareUpdateDxe: Unexpected Failure.  Status = %r\n", Status));
> +    DEBUG ((DEBUG_INFO, "SystemFirmwareUpdateDxe: Status = %r\n", Status));
>       return NULL;
>     }
>   
> @@ -678,6 +678,9 @@ FindMatchingFmpHandles (
>                                   &DescriptorSize
>                                   );
>   
> +    if (OriginalFmpImageInfoBuf == NULL) {
> +      continue;
> +    }
>       //
>       // Loop through the set of EFI_FIRMWARE_IMAGE_DESCRIPTORs.
>       //
>