OvmfPkg/LsiScsiDxe: Examine the incoming SCSI Request Packet

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.

v2: Make LsiScsiPassThru() return EFI_UNSUPPORTED since this function is
    half-implemented

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>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20200717061130.8881-10-glin@suse.com>

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,
@@ -70,6 +159,15 @@ LsiScsiPassThru (
   IN EFI_EVENT                                      Event     OPTIONAL
   )
 {
+  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_UNSUPPORTED;
 }
 

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. It seems sufficient for the common
   // boot scenarios.