Re: [PATCH] MdeModulePkg/NonDiscoverable: fix memory override bug

[Heyi Guo <heyi.guo@linaro.org>]

Hi Ray,

It seems Ard already provided his R-B :)

Thanks.

Heyi


On 10/30/2017 06:23 PM, Ni, Ruiyu wrote:
> I will wait for Ard's feedback. It's an ARM specific module.
>
> Thanks/Ray
>
>> -----Original Message-----
>> From: Zeng, Star
>> Sent: Monday, October 30, 2017 6:07 PM
>> To: Ni, Ruiyu <ruiyu.ni@intel.com>; Heyi Guo <heyi.guo@linaro.org>; linaro-
>> uefi@lists.linaro.org; edk2-devel@lists.01.org
>> Cc: Dong, Eric <eric.dong@intel.com>; Ard Biesheuvel
>> <ard.biesheuvel@linaro.org>; Zeng, Star <star.zeng@intel.com>
>> Subject: RE: [edk2][PATCH] MdeModulePkg/NonDiscoverable: fix memory
>> override bug
>>
>> Ray,
>> Please help take a review to this patch.
>>
>>
>> Thanks,
>> Star
>> -----Original Message-----
>> From: Heyi Guo [mailto:heyi.guo@linaro.org]
>> Sent: Monday, October 30, 2017 1:48 PM
>> To: linaro-uefi@lists.linaro.org; edk2-devel@lists.01.org
>> Cc: Heyi Guo <heyi.guo@linaro.org>; Zeng, Star <star.zeng@intel.com>;
>> Dong, Eric <eric.dong@intel.com>; Ard Biesheuvel
>> <ard.biesheuvel@linaro.org>; Ni, Ruiyu <ruiyu.ni@intel.com>
>> Subject: [edk2][PATCH] MdeModulePkg/NonDiscoverable: fix memory
>> override bug
>>
>> For PciIoPciRead interface, memory prior to Buffer would be written with
>> zeros if Offset was larger than sizeof (Dev->ConfigSpace), which would cause
>> serious system exception.
>>
>> So we add a pre-check branch to avoid memory override.
>>
>> Cc: Star Zeng <star.zeng@intel.com>
>> Cc: Eric Dong <eric.dong@intel.com>
>> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
>> Cc: Ruiyu Ni <ruiyu.ni@intel.com>
>> Contributed-under: TianoCore Contribution Agreement 1.1
>> Signed-off-by: Heyi Guo <heyi.guo@linaro.org>
>> ---
>>   .../Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverablePciDeviceIo.c | 5
>> +++++
>>   1 file changed, 5 insertions(+)
>>
>> diff --git
>> a/MdeModulePkg/Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverable
>> PciDeviceIo.c
>> b/MdeModulePkg/Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverable
>> PciDeviceIo.c
>> index c836ad6..0e42ae4 100644
>> ---
>> a/MdeModulePkg/Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverable
>> PciDeviceIo.c
>> +++
>> b/MdeModulePkg/Bus/Pci/NonDiscoverablePciDeviceDxe/NonDiscoverable
>> Pc
>> +++ iDeviceIo.c
>> @@ -465,6 +465,11 @@ PciIoPciRead (
>>     Address = (UINT8 *)&Dev->ConfigSpace + Offset;
>>     Length = Count << ((UINTN)Width & 0x3);
>>
>> +  if (Offset >= sizeof (Dev->ConfigSpace)) {
>> +    ZeroMem (Buffer, Length);
>> +    return EFI_SUCCESS;
>> +  }
>> +
>>     if (Offset + Length > sizeof (Dev->ConfigSpace)) {
>>       //
>>       // Read all zeroes for config space accesses beyond the first
>> --
>> 1.9.1