Re: [PATCH 09/11] OvmfPkg/LsiScsiDxe: Examine the incoming SCSI Request Packet

["Gary Lin" <glin@suse.com>]

On Tue, Jul 07, 2020 at 12:17:21PM +0200, Laszlo Ersek wrote:
> On 07/01/20 06:04, Gary Lin wrote:
> > This is the first part of LsiScsiPassThru(). Before processing the SCSI
> > Request packet, we have to make sure whether the packet is valid or not.
> > 
> > Cc: Jordan Justen <jordan.l.justen@intel.com>
> > Cc: Laszlo Ersek <lersek@redhat.com>
> > Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
> > Signed-off-by: Gary Lin <glin@suse.com>
> > ---
> >  OvmfPkg/LsiScsiDxe/LsiScsi.c | 100 ++++++++++++++++++++++++++++++++++-
> >  OvmfPkg/LsiScsiDxe/LsiScsi.h |   4 ++
> >  2 files changed, 103 insertions(+), 1 deletion(-)
> > 
> > diff --git a/OvmfPkg/LsiScsiDxe/LsiScsi.c b/OvmfPkg/LsiScsiDxe/LsiScsi.c
> > index b728d18d51df..1bcebd92e455 100644
> > --- a/OvmfPkg/LsiScsiDxe/LsiScsi.c
> > +++ b/OvmfPkg/LsiScsiDxe/LsiScsi.c
> > @@ -52,6 +52,95 @@ LsiScsiReset (
> >    return Out8 (Dev, LSI_REG_ISTAT0, LSI_ISTAT0_SRST);
> >  }
> >  
> > +STATIC
> > +EFI_STATUS
> > +ReportHostAdapterOverrunError (
> > +  OUT EFI_EXT_SCSI_PASS_THRU_SCSI_REQUEST_PACKET *Packet
> > +  )
> > +{
> > +  Packet->SenseDataLength = 0;
> > +  Packet->HostAdapterStatus =
> > +            EFI_EXT_SCSI_STATUS_HOST_ADAPTER_DATA_OVERRUN_UNDERRUN;
> > +  Packet->TargetStatus = EFI_EXT_SCSI_STATUS_TARGET_GOOD;
> > +  return EFI_BAD_BUFFER_SIZE;
> > +}
> > +
> > +/**
> > +
> > +  Check the request packet from the Extended SCSI Pass Thru Protocol. The
> > +  request packet is modified, to be forwarded outwards by LsiScsiPassThru(),
> > +  if invalid or unsupported parameters are detected.
> > +
> > +  @param[in] Dev          The LSI 53C895A SCSI device the packet targets.
> > +
> > +  @param[in] Target       The SCSI target controlled by the LSI 53C895A SCSI
> > +                          device.
> > +
> > +  @param[in] Lun          The Logical Unit Number under the SCSI target.
> > +
> > +  @param[in out] Packet   The Extended SCSI Pass Thru Protocol packet.
> > +
> > +
> > +  @retval EFI_SUCCESS  The Extended SCSI Pass Thru Protocol packet was valid.
> > +
> > +  @return              Otherwise, invalid or unsupported parameters were
> > +                       detected. Status codes are meant for direct forwarding
> > +                       by the EFI_EXT_SCSI_PASS_THRU_PROTOCOL.PassThru()
> > +                       implementation.
> > +
> > + **/
> > +STATIC
> > +EFI_STATUS
> > +LsiScsiCheckRequest (
> > +  IN LSI_SCSI_DEV                                   *Dev,
> > +  IN UINT8                                          Target,
> > +  IN UINT64                                         Lun,
> > +  IN OUT EFI_EXT_SCSI_PASS_THRU_SCSI_REQUEST_PACKET *Packet
> > +  )
> > +{
> > +  if (Target > Dev->MaxTarget || Lun > Dev->MaxLun ||
> > +      Packet->DataDirection > EFI_EXT_SCSI_DATA_DIRECTION_BIDIRECTIONAL ||
> > +      //
> > +      // Trying to receive, but destination pointer is NULL, or contradicting
> > +      // transfer direction
> > +      //
> > +      (Packet->InTransferLength > 0 &&
> > +       (Packet->InDataBuffer == NULL ||
> > +        Packet->DataDirection == EFI_EXT_SCSI_DATA_DIRECTION_WRITE
> > +         )
> > +        ) ||
> > +
> > +      //
> > +      // Trying to send, but source pointer is NULL, or contradicting transfer
> > +      // direction
> > +      //
> > +      (Packet->OutTransferLength > 0 &&
> > +       (Packet->OutDataBuffer == NULL ||
> > +        Packet->DataDirection == EFI_EXT_SCSI_DATA_DIRECTION_READ
> > +         )
> > +        )
> > +    ) {
> > +    return EFI_INVALID_PARAMETER;
> > +  }
> > +
> > +  if (Packet->DataDirection == EFI_EXT_SCSI_DATA_DIRECTION_BIDIRECTIONAL ||
> > +      (Packet->InTransferLength > 0 && Packet->OutTransferLength > 0) ||
> > +      Packet->CdbLength > sizeof Dev->Dma->Cdb) {
> > +    return EFI_UNSUPPORTED;
> > +  }
> > +
> > +  if (Packet->InTransferLength > sizeof Dev->Dma->Data) {
> > +    Packet->InTransferLength = sizeof Dev->Dma->Data;
> > +    return ReportHostAdapterOverrunError (Packet);
> > +  }
> > +  if (Packet->OutTransferLength > sizeof Dev->Dma->Data) {
> > +    Packet->OutTransferLength = sizeof Dev->Dma->Data;
> > +    return ReportHostAdapterOverrunError (Packet);
> > +  }
> > +
> > +  return EFI_SUCCESS;
> > +}
> > +
> >  //
> >  // The next seven functions implement EFI_EXT_SCSI_PASS_THRU_PROTOCOL
> >  // for the LSI 53C895A SCSI Controller. Refer to UEFI Spec 2.3.1 + Errata C,
> > @@ -70,7 +159,16 @@ LsiScsiPassThru (
> >    IN EFI_EVENT                                      Event     OPTIONAL
> >    )
> >  {
> > -  return EFI_UNSUPPORTED;
> > +  EFI_STATUS   Status;
> > +  LSI_SCSI_DEV *Dev;
> > +
> > +  Dev = LSI_SCSI_FROM_PASS_THRU (This);
> > +  Status = LsiScsiCheckRequest (Dev, *Target, Lun, Packet);
> > +  if (EFI_ERROR (Status)) {
> > +    return Status;
> > +  }
> > +
> > +  return EFI_SUCCESS;
> >  }
> >  
> >  EFI_STATUS
> 
> In this patch, we do not implement LsiScsiPassThru() completely yet.
> Therefore we should not return EFI_SUCCESS, just because
> LsiScsiCheckRequest() succeeds.
> 
> (1) So please keep the EFI_UNSUPPORTED value for the last "return"
> statement in the function, for now.
> 
> EFI_UNSUPPORTED should be replaced with EFI_SUCCESS in "[PATCH 10/11]
> OvmfPkg/LsiScsiDxe: Process the SCSI Request Packet".
> 
Agree. EFI_UNSUPPORTED is more reasonable status for this
half-implemented function.

> With that update, for this patch:
> 
> Reviewed-by: Laszlo Ersek <lersek@redhat.com>
> 
Will update this commit in v2.

Thanks,

Gary Lin

> Thanks
> Laszlo
> 
> > diff --git a/OvmfPkg/LsiScsiDxe/LsiScsi.h b/OvmfPkg/LsiScsiDxe/LsiScsi.h
> > index 1e4bbc56f933..9272eb7506c7 100644
> > --- a/OvmfPkg/LsiScsiDxe/LsiScsi.h
> > +++ b/OvmfPkg/LsiScsiDxe/LsiScsi.h
> > @@ -13,6 +13,10 @@
> >  #define _LSI_SCSI_DXE_H_
> >  
> >  typedef struct {
> > +  //
> > +  // The max size of CDB is 32.
> > +  //
> > +  UINT8                           Cdb[32];
> >    //
> >    // Allocate 64KB for read/write buffer.
> >    //
> > 
>