Patch "USB: serial: digi_acceleport: fix incomplete rx sanity check" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

USB: serial: digi_acceleport: fix incomplete rx sanity check

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
usb-serial-digi_acceleport-fix-incomplete-rx-sanity-check.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Johan Hovold <[email protected]>
Date: Tue, 31 Jan 2017 17:17:28 +0100
Subject: USB: serial: digi_acceleport: fix incomplete rx sanity check

From: Johan Hovold <[email protected]>

commit 1b0aed2b1600f6e5c7b9acfbd610a4e351ef5232 upstream.

Make sure the received data has the required headers before parsing it.

Also drop the redundant urb-status check, which has already been handled by the caller.

---
 drivers/usb/serial/digi_acceleport.c |   38 +++++++++++++++++++++--------------
 1 file changed, 23 insertions(+), 15 deletions(-)

@@ -1398,25 +1398,30 @@ static int digi_read_inb_callback(struct
 {
 	struct usb_serial_port *port = urb->context;
 	struct digi_port *priv = usb_get_serial_port_data(port);
-	int opcode = ((unsigned char *)urb->transfer_buffer)[0];
-	int len = ((unsigned char *)urb->transfer_buffer)[1];
-	int port_status = ((unsigned char *)urb->transfer_buffer)[2];
-	unsigned char *data = ((unsigned char *)urb->transfer_buffer) + 3;
+	unsigned char *buf = urb->transfer_buffer;
+	int opcode;
+	int len;
+	int port_status;
+	unsigned char *data;
 	int flag, throttled;
-	int status = urb->status;
-
-	/* do not process callbacks on closed ports */
-	/* but do continue the read chain */
-	if (urb->status == -ENOENT)
-		return 0;
 
 	/* short/multiple packet check */
+	if (urb->actual_length < 2) {
+		dev_warn(&port->dev, "short packet received\n");
+		return -1;
+	}
+
+	opcode = buf[0];
+	len = buf[1];
+
 	if (urb->actual_length != len + 2) {
-		dev_err(&port->dev, "%s: INCOMPLETE OR MULTIPLE PACKET, "
-			"status=%d, port=%d, opcode=%d, len=%d, "
-			"actual_length=%d, status=%d\n", __func__, status,
-			priv->dp_port_num, opcode, len, urb->actual_length,
-			port_status);
+		dev_err(&port->dev, "malformed packet received: port=%d, opcode=%d, len=%d, actual_length=%u\n",
+			priv->dp_port_num, opcode, len, urb->actual_length);
+		return -1;
+	}
+
+	if (opcode == DIGI_CMD_RECEIVE_DATA && len < 1) {
+		dev_err(&port->dev, "malformed data packet received\n");
 		return -1;
 	}
 

@@ -1430,6 +1435,9 @@ static int digi_read_inb_callback(struct
 
 	/* receive data */
 	if (opcode == DIGI_CMD_RECEIVE_DATA) {
+		port_status = buf[2];
+		data = &buf[3];
+
 		/* get flag from port_status */
 		flag = 0;
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/usb-serial-mct_u232-fix-modem-status-error-handling.patch queue-4.9/usb-serial-ark3116-fix-open-error-handling.patch queue-4.9/usb-serial-io_edgeport-fix-epic-descriptor-handling.patch queue-4.9/usb-serial-ti_usb_3410_5052-fix-control-message-error-handling.patch queue-4.9/usb-serial-keyspan_pda-fix-receive-sanity-checks.patch queue-4.9/usb-serial-sierra-fix-bogus-alternate-setting-assumption.patch queue-4.9/usb-serial-ssu100-fix-control-message-error-handling.patch queue-4.9/usb-serial-digi_acceleport-fix-incomplete-rx-sanity-check.patch queue-4.9/usb-serial-io_edgeport-fix-descriptor-error-handling.patch queue-4.9/usb-serial-quatech2-fix-control-message-error-handling.patch queue-4.9/usb-serial-ftdi_sio-fix-latency-timer-error-handling.patch