Re: [PATCH] MdeModulePkg: XhciDxe: Prevent illegal memory access in XhcSetHsee

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

On Tue, 25 Sep 2018 at 19:59, Marcin Wojtas <mw@semihalf.com> wrote:
>
> REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1206
>
> Newly added XhcSetHsee() routine reads 4 bytes into
> a UINT16 variable causing issues on PCIE and NonDiscoverable
> Xhci controllers. Fix that.
>
> Cc: Ruiyu Ni <ruiyu.ni@intel.com>
> Cc: Fei1 Wang <fei1.wang@intel.com>
> Cc: Star Zeng <star.zeng@intel.com>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Marcin Wojtas <mw@semihalf.com>
> ---
>  MdeModulePkg/Bus/Pci/XhciDxe/XhciReg.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/MdeModulePkg/Bus/Pci/XhciDxe/XhciReg.c b/MdeModulePkg/Bus/Pci/XhciDxe/XhciReg.c
> index 89f073e..dfe5f6c 100644
> --- a/MdeModulePkg/Bus/Pci/XhciDxe/XhciReg.c
> +++ b/MdeModulePkg/Bus/Pci/XhciDxe/XhciReg.c
> @@ -607,7 +607,7 @@ XhcSetHsee (
>    PciIo = Xhc->PciIo;
>    Status = PciIo->Pci.Read (
>                          PciIo,
> -                        EfiPciIoWidthUint16,
> +                        EfiPciIoWidthUint8,
>                          PCI_COMMAND_OFFSET,
>                          sizeof (XhciCmd),
>                          &XhciCmd
> --
> 2.7.4
>

Well spotted! But I think a single read of 16 bits is more appropriate
here though.