On Thu, Aug 09, 2018 at 03:15:38PM +0900, 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.
I find this done in CreatePopulateInstallShellProtocol() in Application/Shell/ShellProtocol.c, is that the one you see?
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.
Where we find non-spec-compliant code in EDK2, we want to fix EDK2. That doesn't mean that we don't perhaps want to work around it in U-Boot anyway. But if we do, I would prefer if we could spam the console a bit as well, to warn people of badly behaving apps.
However...
The patch provides a minimum mitigation of parameter check.
Signed-off-by: AKASHI Takahiro takahiro.akashi@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 */
- if (notify_tpl && (is_valid_tpl(notify_tpl) != EFI_SUCCESS))
From the UEFI spec (2.7) description of CreateEvent() boot service:
--- The EVT_NOTIFY_WAIT and EVT_NOTIFY_SIGNAL flags are exclusive. If neither flag is specified, the caller does not require any notification concerning the event and the NotifyTpl, NotifyFunction, and NotifyContext parameters are ignored. ---
So it's not a workaround for Shell specifically. However, based on that text, something like
if (type & (EVT_NOTIFY_WAIT | EVT_NOTIFY_SIGNAL)) if ((is_valid_tpl(notify_tpl) != EFI_SUCCESS))
may resolve this in a more compliant way.
Of course, this may require additional changes to the remainder of the function.
/ Leif
return EFI_INVALID_PARAMETER;evt = calloc(1, sizeof(struct efi_event));
2.18.0