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: v5.16-rc6~13^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5da5231bb47864e5dd6c6731151e98b6ee498827;p=thirdparty%2Fkernel%2Flinux.git

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 1b84d5526d77a..313e9475507b5 100644
--- 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;