[PATCH AUTOSEL 4.14 37/44] libata: have ata_scsi_rw_xlat() fail invalid passthrough requests

[PATCH AUTOSEL 4.14 37/44] libata: have ata_scsi_rw_xlat() fail invalid passthrough requests

[Sasha Levin]

From: Jens Axboe <axboe@kernel.dk>

[ Upstream commit 2d7271501720038381d45fb3dcbe4831228fc8cc ]

For passthrough requests, libata-scsi takes what the user passes in
as gospel. This can be problematic if the user fills in the CDB
incorrectly. One example of that is in request sizes. For read/write
commands, the CDB contains fields describing the transfer length of
the request. These should match with the SG_IO header fields, but
libata-scsi currently does no validation of that.

Check that the number of blocks in the CDB for passthrough requests
matches what was mapped into the request. If the CDB asks for more
data then the validated SG_IO header fields, error it.

Reported-by: Krishna Ram Prakash R <krp@gtux.in>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/ata/libata-scsi.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index bf5777bc04d35..eb0c4ee205258 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -1804,6 +1804,21 @@ static unsigned int ata_scsi_verify_xlat(struct ata_queued_cmd *qc)
 	return 1;
 }
 
+static bool ata_check_nblocks(struct scsi_cmnd *scmd, u32 n_blocks)
+{
+	struct request *rq = scmd->request;
+	u32 req_blocks;
+
+	if (!blk_rq_is_passthrough(rq))
+		return true;
+
+	req_blocks = blk_rq_bytes(rq) / scmd->device->sector_size;
+	if (n_blocks > req_blocks)
+		return false;
+
+	return true;
+}
+
 /**
  *	ata_scsi_rw_xlat - Translate SCSI r/w command into an ATA one
  *	@qc: Storage for translated ATA taskfile
@@ -1848,6 +1863,8 @@ static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc)
 		scsi_10_lba_len(cdb, &block, &n_block);
 		if (cdb[1] & (1 << 3))
 			tf_flags |= ATA_TFLAG_FUA;
+		if (!ata_check_nblocks(scmd, n_block))
+			goto invalid_fld;
 		break;
 	case READ_6:
 	case WRITE_6:
@@ -1862,6 +1879,8 @@ static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc)
 		 */
 		if (!n_block)
 			n_block = 256;
+		if (!ata_check_nblocks(scmd, n_block))
+			goto invalid_fld;
 		break;
 	case READ_16:
 	case WRITE_16:
@@ -1872,6 +1891,8 @@ static unsigned int ata_scsi_rw_xlat(struct ata_queued_cmd *qc)
 		scsi_16_lba_len(cdb, &block, &n_block);
 		if (cdb[1] & (1 << 3))
 			tf_flags |= ATA_TFLAG_FUA;
+		if (!ata_check_nblocks(scmd, n_block))
+			goto invalid_fld;
 		break;
 	default:
 		DPRINTK("no-byte command\n");
-- 
2.20.1

[PATCH AUTOSEL 4.14 38/44] libata: add SG safety checks in SFF pio transfers

[Sasha Levin]

From: Jens Axboe <axboe@kernel.dk>

[ Upstream commit 752ead44491e8c91e14d7079625c5916b30921c5 ]

Abort processing of a command if we run out of mapped data in the
SG list. This should never happen, but a previous bug caused it to
be possible. Play it safe and attempt to abort nicely if we don't
have more SG segments left.

Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/ata/libata-sff.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/ata/libata-sff.c b/drivers/ata/libata-sff.c
index cc2f2e35f4c2e..8c36ff0c2dd49 100644
--- a/drivers/ata/libata-sff.c
+++ b/drivers/ata/libata-sff.c
@@ -704,6 +704,10 @@ static void ata_pio_sector(struct ata_queued_cmd *qc)
 	unsigned int offset;
 	unsigned char *buf;
 
+	if (!qc->cursg) {
+		qc->curbytes = qc->nbytes;
+		return;
+	}
 	if (qc->curbytes == qc->nbytes - qc->sect_size)
 		ap->hsm_task_state = HSM_ST_LAST;
 
@@ -729,6 +733,8 @@ static void ata_pio_sector(struct ata_queued_cmd *qc)
 
 	if (qc->cursg_ofs == qc->cursg->length) {
 		qc->cursg = sg_next(qc->cursg);
+		if (!qc->cursg)
+			ap->hsm_task_state = HSM_ST_LAST;
 		qc->cursg_ofs = 0;
 	}
 }
-- 
2.20.1