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Commit a8d28d80 authored by Johan Hovold's avatar Johan Hovold Committed by Greg Kroah-Hartman
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USB: serial: digi_acceleport: fix OOB data sanity check 



commit 2d380889215fe20b8523345649dee0579821800c upstream.

Make sure to check for short transfers to avoid underflow in a loop
condition when parsing the receive buffer.

Also fix an off-by-one error in the incomplete sanity check which could
lead to invalid data being parsed.

Fixes: 8c209e67 ("USB: make actual_length in struct urb field u32")
Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Reviewed-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 4161529e

drivers/usb/serial/digi_acceleport.c

+9 −5
Original line number Diff line number Diff line
@@ -1483,16 +1483,20 @@ static int digi_read_oob_callback(struct urb *urb) 
	struct usb_serial *serial = port->serial;

	struct tty_struct *tty;

	struct digi_port *priv = usb_get_serial_port_data(port);

	unsigned char *buf = urb->transfer_buffer;

	int opcode, line, status, val;

	int i;

	unsigned int rts;



	if (urb->actual_length < 4)

		return -1;



	/* handle each oob command */

	for (i = 0; i < urb->actual_length - 3;) {

		opcode = ((unsigned char *)urb->transfer_buffer)[i++];

		line = ((unsigned char *)urb->transfer_buffer)[i++];

		status = ((unsigned char *)urb->transfer_buffer)[i++];

		val = ((unsigned char *)urb->transfer_buffer)[i++];

	for (i = 0; i < urb->actual_length - 4; i += 4) {

		opcode = buf[i];

		line = buf[i + 1];

		status = buf[i + 2];

		val = buf[i + 3];



		dev_dbg(&port->dev, "digi_read_oob_callback: opcode=%d, line=%d, status=%d, val=%d\n",

			opcode, line, status, val);