[U-Boot] [RFC] efi_loader: workaround for EDK2's shell.efi
Alexander Graf
agraf at suse.de
Thu Aug 9 06:55:06 UTC 2018
On 09.08.18 07:15, AKASHI Takahiro wrote:
> The commit 21b3edfc964 ("efi_loader: check parameters of CreateEvent")
> enforces a strict parameter check at CreateEvent(). Unfortunately,
> however, EDK2's Shell.efi calls this function with notify_tpl == 0.
>
> The patch above does right thing and we'd better fix the issue on EDK2
> side, and yet we might want a workaround allowing for running un-modified
> version of EDK2 in short-term solution.
... of the EDK2 shell ...
and it's not just about short term - we always want to be compatible :).
So what's the reason this does not trigger in edk2? Are they considering
TPL 0 a valid TPL always or did they just forget the check in create
event? If they always consider TPL 0 valid, we better change
is_valid_tpl to ensure compatibility with edk2's behavior.
> The patch provides a minimum mitigation of parameter check.
>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
> ---
> lib/efi_loader/efi_boottime.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
> index 2281703f261..e7a19c35415 100644
> --- a/lib/efi_loader/efi_boottime.c
> +++ b/lib/efi_loader/efi_boottime.c
> @@ -627,7 +627,8 @@ efi_status_t efi_create_event(uint32_t type, efi_uintn_t notify_tpl,
> return EFI_INVALID_PARAMETER;
> }
>
> - if (is_valid_tpl(notify_tpl) != EFI_SUCCESS)
> + /* notify_tpl == 0: workaround for EDK2's Shell.efi */
That comment is too undescriptive. Better write something like "EDK2
accepts TPL 0 in CreateEvent, so to ensure compatibility we should do
the same. EDK2 Shell.efi depends on this."
Alex
> + if (notify_tpl && (is_valid_tpl(notify_tpl) != EFI_SUCCESS))
> return EFI_INVALID_PARAMETER;
>
> evt = calloc(1, sizeof(struct efi_event));
>
More information about the U-Boot
mailing list