[PATCH 4.19 45/52] scsi: iscsi: Verify lengths on passthrough PDUs

[Greg Kroah-Hartman]

From: Chris Leech <cleech@xxxxxxxxxx>

commit f9dbdf97a5bd92b1a49cee3d591b55b11fd7a6d5 upstream.

Open-iSCSI sends passthrough PDUs over netlink, but the kernel should be
verifying that the provided PDU header and data lengths fall within the
netlink message to prevent accessing beyond that in memory.

Cc: stable@xxxxxxxxxxxxxxx
Reported-by: Adam Nichols <adam@xxxxxxxxxxxx>
Reviewed-by: Lee Duncan <lduncan@xxxxxxxx>
Reviewed-by: Mike Christie <michael.christie@xxxxxxxxxx>
Signed-off-by: Chris Leech <cleech@xxxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/scsi/scsi_transport_iscsi.c |    9 +++++++++
 1 file changed, 9 insertions(+)

--- a/drivers/scsi/scsi_transport_iscsi.c
+++ b/drivers/scsi/scsi_transport_iscsi.c
@@ -3507,6 +3507,7 @@ iscsi_if_recv_msg(struct sk_buff *skb, s
 {
 	int err = 0;
 	u32 portid;
+	u32 pdu_len;
 	struct iscsi_uevent *ev = nlmsg_data(nlh);
 	struct iscsi_transport *transport = NULL;
 	struct iscsi_internal *priv;
@@ -3624,6 +3625,14 @@ iscsi_if_recv_msg(struct sk_buff *skb, s
 			err = -EINVAL;
 		break;
 	case ISCSI_UEVENT_SEND_PDU:
+		pdu_len = nlh->nlmsg_len - sizeof(*nlh) - sizeof(*ev);
+
+		if ((ev->u.send_pdu.hdr_size > pdu_len) ||
+		    (ev->u.send_pdu.data_size > (pdu_len - ev->u.send_pdu.hdr_size))) {
+			err = -EINVAL;
+			break;
+		}
+
 		conn = iscsi_conn_lookup(ev->u.send_pdu.sid, ev->u.send_pdu.cid);
 		if (conn)
 			ev->r.retcode =	transport->send_pdu(conn,