libata: if T_LENGTH is zero, dma direction should be DMA_NONE

Avoid data corruption by rejecting pass-through commands where
T_LENGTH is zero (No data is transferred) and the dma direction
is not DMA_NONE.

Cc: <stable@vger.kernel.org>
Reported-by: syzkaller<syzkaller@googlegroups.com>
Signed-off-by: George Kennedy<george.kennedy@oracle.com>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 1b84d55..313e947 100644 (file)
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -2859,8 +2859,19 @@ static unsigned int ata_scsi_pass_thru(struct ata_queued_cmd *qc)
                goto invalid_fld;
        }
 
-       if (ata_is_ncq(tf->protocol) && (cdb[2 + cdb_offset] & 0x3) == 0)
-               tf->protocol = ATA_PROT_NCQ_NODATA;
+       if ((cdb[2 + cdb_offset] & 0x3) == 0) {
+               /*
+                * When T_LENGTH is zero (No data is transferred), dir should
+                * be DMA_NONE.
+                */
+               if (scmd->sc_data_direction != DMA_NONE) {
+                       fp = 2 + cdb_offset;
+                       goto invalid_fld;
+               }
+
+               if (ata_is_ncq(tf->protocol))
+                       tf->protocol = ATA_PROT_NCQ_NODATA;
+       }
 
        /* enable LBA */
        tf->flags |= ATA_TFLAG_LBA;