From mboxrd@z Thu Jan 1 00:00:00 1970 From: Leif Lindholm Date: Thu, 9 Aug 2018 14:08:32 +0100 Subject: [U-Boot] [RFC] efi_loader: workaround for EDK2's shell.efi In-Reply-To: <20180809061538.6624-1-takahiro.akashi@linaro.org> References: <20180809061538.6624-1-takahiro.akashi@linaro.org> Message-ID: <20180809130832.cgihbbrytnvk6qvr@bivouac.eciton.net> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de 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 > --- > 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 >