From: George Kennedy <george.kennedy@oracle.com>
Date: Tue, 14 Dec 2021 14:45:10 +0000 (-0500)
Subject: libata: if T_LENGTH is zero, dma direction should be DMA_NONE
X-Git-Tag: v4.19.222~20
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=61295b8cadb670ba1ede4c08a1824b9b0f7b1560;p=users%2Fdwmw2%2Flinux.git

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

commit 5da5231bb47864e5dd6c6731151e98b6ee498827 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index e7af41d95490d..0950d6fda89cf 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -3181,8 +3181,19 @@ 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;