Commit c9ee8144 authored Dec 14, 2021 by George Kennedy Committed by Greg Kroah-Hartman Dec 22, 2021

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&lt;syzkaller@googlegroups.com>
Signed-off-by: George <Kennedy&lt;george.kennedy@oracle.com>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 62889094

drivers/ata/libata-scsi.c

+13 −2

Original line number	Diff line number	Diff line
		@@ -3164,8 +3164,19 @@ 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)
		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;