Re: [PATCH] SecurityPkg Tcg2Dxe: Get correct digest list size

["Yao, Jiewen" <jiewen.yao@intel.com>]

Yes, that is correct. I misunderstand the patch.

Reviewed-by: Jiewen.yao@intel.com<mailto:Jiewen.yao@intel.com>

At same time, I would recommend we update PEI with comment on why we can use GetDigestListSize (DigestList) in PEI, but not use GetDigestListSize in DXE, because people may compare these 2 version.

Thank you
Yao Jiewen


From: Zeng, Star
Sent: Friday, November 18, 2016 8:51 AM
To: Yao, Jiewen <jiewen.yao@intel.com>; edk2-devel@lists.01.org
Cc: Zhang, Chao B <chao.b.zhang@intel.com>
Subject: Re: [edk2] [PATCH] SecurityPkg Tcg2Dxe: Get correct digest list size

On 2016/11/17 20:32, Yao, Jiewen wrote:
> Hi star
> I am sorry that I am confused on this patch.
>
> 1) Below update is not related to the GIT message.
> I think there is nothing wrong with previous code. May I know if you observe something?

The following GetDigestListBinSize (DigestBuffer) needs *DigestBuffer
points to real digest buffer*.

>
>> -        DigestBuffer = CopyDigestListToBuffer (DigestBuffer, DigestList,
>> mTcgDxeData.BsCap.ActivePcrBanks);
>> -        CopyMem (DigestBuffer, &NewEventHdr->EventSize,
>> sizeof(NewEventHdr->EventSize));
>> -        DigestBuffer = DigestBuffer + sizeof(NewEventHdr->EventSize);
>> +        EventSizePtr = CopyDigestListToBuffer (DigestBuffer, DigestList,
>> mTcgDxeData.BsCap.ActivePcrBanks);
>> +        CopyMem (EventSizePtr, &NewEventHdr->EventSize,
>> sizeof(NewEventHdr->EventSize));
>
> 2) I believe "GetDigestListSize (DigestList)" should be same as "GetDigestListBinSize (DigestBuffer)"
> May I know how did you observe such error?

DigestList points to the original full un-compacted digest list,
DigestBuffer points to the copied partial compacted digest list.

Thanks,
Star

>
>
> Thank you
> Yao Jiewen
>
>
>
>> -----Original Message-----
>> From: Zeng, Star
>> Sent: Thursday, November 17, 2016 5:27 PM
>> To: edk2-devel@lists.01.org<mailto:edk2-devel@lists.01.org>
>> Cc: Zeng, Star <star.zeng@intel.com<mailto:star.zeng@intel.com>>; Yao, Jiewen <jiewen.yao@intel.com<mailto:jiewen.yao@intel.com>>;
>> Zhang, Chao B <chao.b.zhang@intel.com<mailto:chao.b.zhang@intel.com>>
>> Subject: [PATCH] SecurityPkg Tcg2Dxe: Get correct digest list size
>>
>> Current code uses GetDigestListSize(DigestList) to get
>> digest list size, that is incorrect.
>> The code should get digest list size of digests copied
>> into event2 log, those digests are compacted, so
>> GetDigestListBinSize() should be used.
>>
>> Cc: Jiewen Yao <jiewen.yao@intel.com<mailto:jiewen.yao@intel.com>>
>> Cc: Chao Zhang <chao.b.zhang@intel.com<mailto:chao.b.zhang@intel.com>>
>> Contributed-under: TianoCore Contribution Agreement 1.0
>> Signed-off-by: Star Zeng <star.zeng@intel.com<mailto:star.zeng@intel.com>>
>> ---
>>  SecurityPkg/Tcg/Tcg2Dxe/Tcg2Dxe.c | 8 ++++----
>>  1 file changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/SecurityPkg/Tcg/Tcg2Dxe/Tcg2Dxe.c
>> b/SecurityPkg/Tcg/Tcg2Dxe/Tcg2Dxe.c
>> index d5a32307db6e..f4740a34444c 100644
>> --- a/SecurityPkg/Tcg/Tcg2Dxe/Tcg2Dxe.c
>> +++ b/SecurityPkg/Tcg/Tcg2Dxe/Tcg2Dxe.c
>> @@ -970,6 +970,7 @@ TcgDxeLogHashEvent (
>>    EFI_STATUS                        RetStatus;
>>    TCG_PCR_EVENT2                    TcgPcrEvent2;
>>    UINT8                             *DigestBuffer;
>> +  UINT32                            *EventSizePtr;
>>
>>    DEBUG ((EFI_D_INFO, "SupportedEventLogs - 0x%08x\n",
>> mTcgDxeData.BsCap.SupportedEventLogs));
>>
>> @@ -1006,9 +1007,8 @@ TcgDxeLogHashEvent (
>>          TcgPcrEvent2.PCRIndex = NewEventHdr->PCRIndex;
>>          TcgPcrEvent2.EventType = NewEventHdr->EventType;
>>          DigestBuffer = (UINT8 *)&TcgPcrEvent2.Digest;
>> -        DigestBuffer = CopyDigestListToBuffer (DigestBuffer, DigestList,
>> mTcgDxeData.BsCap.ActivePcrBanks);
>> -        CopyMem (DigestBuffer, &NewEventHdr->EventSize,
>> sizeof(NewEventHdr->EventSize));
>> -        DigestBuffer = DigestBuffer + sizeof(NewEventHdr->EventSize);
>> +        EventSizePtr = CopyDigestListToBuffer (DigestBuffer, DigestList,
>> mTcgDxeData.BsCap.ActivePcrBanks);
>> +        CopyMem (EventSizePtr, &NewEventHdr->EventSize,
>> sizeof(NewEventHdr->EventSize));
>>
>>          //
>>          // Enter critical region
>> @@ -1017,7 +1017,7 @@ TcgDxeLogHashEvent (
>>          Status = TcgDxeLogEvent (
>>                     mTcg2EventInfo[Index].LogFormat,
>>                     &TcgPcrEvent2,
>> -                   sizeof(TcgPcrEvent2.PCRIndex) +
>> sizeof(TcgPcrEvent2.EventType) + GetDigestListSize (DigestList) +
>> sizeof(TcgPcrEvent2.EventSize),
>> +                   sizeof(TcgPcrEvent2.PCRIndex) +
>> sizeof(TcgPcrEvent2.EventType) + GetDigestListBinSize (DigestBuffer) +
>> sizeof(TcgPcrEvent2.EventSize),
>>                     NewEventData,
>>                     NewEventHdr->EventSize
>>                     );
>> --
>> 2.7.0.windows.1