Re: 答复: [ScsiDiskDxe] Implict type conversion bug

["Wu, Hao A" <hao.a.wu@intel.com>]

Hi Gary,

Thanks for the reporting, I will take a look at all the cases you mentioned.

Best Regards,
Hao Wu


> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of
> Guoheyi
> Sent: Tuesday, April 11, 2017 3:05 PM
> To: Zeng, Star; edk2-devel@lists.01.org
> Cc: Tian, Feng
> Subject: [edk2] 答复: [ScsiDiskDxe] Implict type conversion bug
> 
> Hi Star,
> 
> I searched " LastLba3" in EDK2 code and found there were some other code
> similar to this one, could you please check whether they need to be fixed as
> well?
> 
> IntelFrameworkModulePkg/Bus/Pci/IdeBusDxe/Atapi.c:        IdeDev-
> >BlkIo.Media->LastBlock = (Data.LastLba3 << 24) |
> IntelFrameworkModulePkg/Bus/Pci/IdeBusDxe/Atapi.c:          IdeDev-
> >BlkIo.Media->LastBlock =  (FormatData.LastLba3 << 24) |
> MdeModulePkg/Bus/Ufs/UfsBlockIoPei/UfsBlockIoPei.c:    Private-
> >Media[DeviceIndex].LastBlock  = (Capacity16.LastLba3 << 24) |
> (Capacity16.LastLba2 << 16) | (Capacity16.LastLba1 << 8) |
> Capacity16.LastLba0;
> MdeModulePkg/Bus/Ufs/UfsBlockIoPei/UfsBlockIoPei.c:    Private-
> >Media[DeviceIndex].LastBlock  = (Capacity.LastLba3 << 24) |
> (Capacity.LastLba2 << 16) | (Capacity.LastLba1 << 8) | Capacity.LastLba0;
> MdeModulePkg/Bus/Pci/IdeBusPei/AtapiPeim.c:      MediaInfo->LastBlock    =
> (Data.LastLba3 << 24) | (Data.LastLba2 << 16) | (Data.LastLba1 << 8) |
> Data.LastLba0;
> MdeModulePkg/Bus/Pci/IdeBusPei/AtapiPeim.c:        MediaInfo->LastBlock =
> (FormatData.LastLba3 << 24) |
> 
> (I think the two lines below should be OK for LastBlock is defined as UINT32)
> MdeModulePkg/Bus/Usb/UsbBotPei/PeiAtapi.c:  LastBlock = (Data.LastLba3 <<
> 24) | (Data.LastLba2 << 16) | (Data.LastLba1 << 8) | Data.LastLba0;
> MdeModulePkg/Bus/Usb/UsbBotPei/PeiAtapi.c:    LastBlock =
> (FormatData.LastLba3 << 24) | (FormatData.LastLba2 << 16) |
> (FormatData.LastLba1 << 8) | FormatData.LastLba0;
> 
> 
> Thanks and regards,
> 
> Gary (Heyi Guo)
> 
> 
> -----邮件原件-----
> 发件人: Guoheyi
> 发送时间: 2017年4月11日 12:25
> 收件人: 'Zeng, Star'; edk2-devel@lists.01.org
> 抄送: Tian, Feng
> 主题: 答复: [edk2] [ScsiDiskDxe] Implict type conversion bug
> 
> Thanks for your quick fix :)
> 
> -----邮件原件-----
> 发件人: Zeng, Star [mailto:star.zeng@intel.com]
> 发送时间: 2017年4月10日 17:48
> 收件人: Guoheyi; edk2-devel@lists.01.org
> 抄送: Tian, Feng; Zeng, Star
> 主题: RE: [edk2] [ScsiDiskDxe] Implict type conversion bug
> 
> Hao has sent patch for this issue.
> You can search emails with title "[edk2] [PATCH] MdeModulePkg/ScsiDiskDxe:
> Fix potential implicit sign extension".
> 
> Thanks,
> Star
> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of
> Guoheyi
> Sent: Monday, April 10, 2017 5:40 PM
> To: edk2-devel@lists.01.org
> Cc: Tian, Feng <feng.tian@intel.com>
> Subject: [edk2] [ScsiDiskDxe] Implict type conversion bug
> 
> Hi folks,
> 
> In MdeModulePkg/Bus/Scsi/ScsiDiskDxe/ScsiDisk.c, Line 2757, we have the
> code as below:
> 
>     ScsiDiskDevice->BlkIo.Media->LastBlock =  (Capacity10->LastLba3 << 24) |
>                                               (Capacity10->LastLba2 << 16) |
>                                               (Capacity10->LastLba1 << 8)  |
>                                                Capacity10->LastLba0;
> 
> However, we tested on VS2008 and found that the intermediate result would be
> convert to INT32 then INT64 implicitly, so the result will be sign extended and
> LastBlock may not be assigned with what is expected. We can simply test
> LastLba3 >= 0x80 to see what will happen.
> 
> Please let me know your comments.
> 
> Thanks and regards,
> 
> Gary (Heyi Guo)
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