[PATCH 07/13] efi_loader: image_loader: add digest-based verification for signed image

AKASHI Takahiro
2020-06-02T05:31:47Z

Heinrich,

On Sat, May 30, 2020 at 09:09:30AM +0200, Heinrich Schuchardt wrote:
> On 5/29/20 8:41 AM, AKASHI Takahiro wrote:
> > In case that a type of certificate in "db" or "dbx" is
> > EFI_CERT_X509_SHA256_GUID, it is actually not a certificate which contains
> > a public key for RSA decryption, but a digest of image to be loaded.
> > If the value matches to a value calculated from a given binary image, it is
> > granted for loading.
> >
> > With this patch, common digest check code, which used to be used for
> > unsigned image verification, will be extracted from
> > efi_signature_verify_with_sigdb() into efi_signature_lookup_digest(), and
> > extra step for digest check will be added to efi_image_authenticate().
>
> Could you, please, add comments in the code describing this process flow.

All the necessary code is contained in efi_signature_lookup_digest(),
but I'll add some comments in efi_image_authenticate().

Thanks,
-Takahiro Akashi

> Best regards
>
> Heinrich