Re: [edk2-devel] [PATCH resend] MdeModulePkg/EsrtDxe: allocate ESRT table from RtServicesData memory

["Ard Biesheuvel" <ard.biesheuvel@linaro.org>]

On Fri, 19 Apr 2019 at 22:04, Kinney, Michael D
<michael.d.kinney@intel.com> wrote:
>
> Ard,
>
> Saw your patch to cache the GUID table.  The ESRT Table
> is not that much bigger, so the algorithm may be simpler
> if you just make a copy of the ESRT table with the
> active entries.
>
> * 16+24 bytes per ESRT entry.
> * 16 bytes/entry for just the GUID.
>
> The only advantage of checking against the ESRT GUID at
> RT is to reject capsules that will be rejected when the
> capsule is processed later.  This can prevent extra reboots
> if an OS agent is sending capsules that do not really
> apply to the current system.  I expect OS agent to only
> send capsules that are in the ESRT.
>

Yeah. The only problem is that some capsules have no header at all,
and so without a GUID check, we might end up interpreting random data
as the capsule's HeaderSize field, which would be bad.

In general, I think we should be robust against random junk being
passed into the QueryCapsuleCapabilities() runtime service.