Re: [PATCH v13 10/15] FWU: Add support for the FWU Multi Bank Update feature

Ilias Apalodimas
2022-10-14T07:59:13Z

[...]

> > > > > +}
> > > > > +
> > > > > +static __maybe_unused efi_status_t fwu_empty_capsule_process(
> > > > > + struct efi_capsule_header *capsule)
> > > > > +{
> > > > > + int status;
> > > > > + u32 active_idx;
> > > > > + efi_status_t ret;
> > > > > + efi_guid_t *image_guid;
> > > > > +
> > > > > + if (!guidcmp(&capsule->capsule_guid,
> > > > > + &fwu_guid_os_request_fw_revert)) {
> > > > > + /*
> > > > > + * One of the previously updated image has
> > > > > + * failed the OS acceptance test. OS has
> > > > > + * requested to revert back to the earlier
> > > > > + * boot index
> > > > > + */
> > > > > + status = fwu_revert_boot_index();
> > > > > + ret = fwu_to_efi_error(status);
> > > > > + if (ret == EFI_SUCCESS)
> > > > > + log_info("Reverted the FWU active_index. Recommend rebooting the system\n");
> > > > > + else
> > > > > + log_err("Failed to revert the FWU boot index\n");
> > > > > + } else {
> > > >
> > > > We should be explicit on the GUID checking here. IOW if someone hands you
> > > > over and empty capsule with a guid !fwu_guid_os_request_fw_revert you'll
> > > > accept the capsule
> > >
> > > This won't happen since this function is called only for empty
> > > capsules. Will handle the other two review comments.
> >
> > I am not sure I am following. Why can't it happen? If someone create
> > an empty capsule with an invalid (by invalid I mean none of the 2
> > GUIDs the spec expects), you'll end up trying to accept the firmware
> > no?
>
> That will be checked in the fwu_empty_capsule(). Only if this function
> returns true, will the fwu_empty_capsule_process() get called. So the
> capsule_guid should either be one for accept or a revert capsule.
>
> -sughosh

Right in this case then why don't we pass an extra argument to
fwu_empty_capsule_process() instead and skip the extra guidcmp?

Thanks
/Ilias
>
> >
> > Thanks
> > /Ilias
> > >
> > > -sughosh
> > >
> > > >
> > > > > + /*
> > > > > + * Image accepted by the OS. Set the acceptance
> > > > > + * status for the image.
> > > > > + */
> > > > > + image_guid = (void *)(char *)capsule +
> > > > > + capsule->header_size;
> > > > > +
> > > > > + status = fwu_get_active_index(&active_idx);
> > > > > + ret = fwu_to_efi_error(status);
> > > > > + if (ret != EFI_SUCCESS) {
> > > > > + log_err("Unable to get the active_index from the FWU metadata\n");
> > > > > + return ret;
> > > > > + }
> > > > > +
> > > > > + status = fwu_accept_image(image_guid, active_idx);
> > > > > + ret = fwu_to_efi_error(status);
> > > > > + if (ret != EFI_SUCCESS)
> > > > > + log_err("Unable to set the Accept bit for the image %pUs\n",
> > > > > + image_guid);
> > > > > + }
> > > > > +
> > > > > + return ret;
> > > > > +}
> > > > > +
> > > > > +static __maybe_unused void fwu_post_update_checks(
> > > > > + struct efi_capsule_header *capsule,
> > > > > + bool *fw_accept_os, bool *capsule_update)
> > > > > +{
> > > > > + if (fwu_empty_capsule(capsule))
> > > > > + *capsule_update = false;
> > > > > + else
> > > > > + if (!*fw_accept_os)
> > > >
> > > > This line should fold to the upper one
> > > >
> > > > > + *fw_accept_os =
> > > > > + capsule->flags & FW_ACCEPT_OS ? true : false;
> > > > > +}
> > > > > +
> > > > > +static __maybe_unused efi_status_t fwu_post_update_process(bool fw_accept_os)
> > > > > +{
> > > > > + int status;
> > > > > + u32 update_index;
> > > > > + efi_status_t ret;
> > > > > +
> > > > > + status = fwu_plat_get_update_index(&update_index);
> > > > > + if (status < 0) {
> > > > > + log_err("Failed to get the FWU update_index value\n");
> > > > > + return EFI_DEVICE_ERROR;
> > > > > + }
> > > > > +
> > > > > + /*
> > > > > + * All the capsules have been updated successfully,
> > > > > + * update the FWU metadata.
> > > > > + */
> > > > > + log_debug("Update Complete. Now updating active_index to %u\n",
> > > > > + update_index);
> > > > > + status = fwu_set_active_index(update_index);
> > > > > + ret = fwu_to_efi_error(status);
> > > > > + if (ret != EFI_SUCCESS) {
> > > > > + log_err("Failed to update FWU metadata index values\n");
> > > > > + } else {
> > > > > + log_debug("Successfully updated the active_index\n");
> > > >
> > > > [...]
> > > >
> > > > Thanks
> > > > /Ilias