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Commit 5ed8d410 authored by Johan Hovold's avatar Johan Hovold
Browse files

USB: serial: spcp8x5: fix modem-status handling 



Make sure to detect short control transfers and return zero on success
when retrieving the modem status.

This fixes the TIOCMGET implementation which since e1ed212d ("USB:
spcp8x5: add proper modem-status support") has returned TIOCM_LE on
successful retrieval, and avoids leaking bits from the stack on short
transfers.

This also fixes the carrier-detect implementation which since the above
mentioned commit unconditionally has returned true.

Fixes: e1ed212d ("USB: spcp8x5: add proper modem-status support")
Cc: stable <stable@vger.kernel.org>
Reviewed-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
parent 8c34cb8d

drivers/usb/serial/spcp8x5.c

+7 −1
Original line number Original line Diff line number Diff line
@@ -232,11 +232,17 @@ static int spcp8x5_get_msr(struct usb_serial_port *port, u8 *status) 
	ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),

	ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),

			      GET_UART_STATUS, GET_UART_STATUS_TYPE,

			      GET_UART_STATUS, GET_UART_STATUS_TYPE,

			      0, GET_UART_STATUS_MSR, buf, 1, 100);

			      0, GET_UART_STATUS_MSR, buf, 1, 100);

	if (ret < 0)

	if (ret < 1) {

		dev_err(&port->dev, "failed to get modem status: %d\n", ret);

		dev_err(&port->dev, "failed to get modem status: %d\n", ret);

		if (ret >= 0)

			ret = -EIO;

		goto out;

	}





	dev_dbg(&port->dev, "0xc0:0x22:0:6  %d - 0x02%x\n", ret, *buf);

	dev_dbg(&port->dev, "0xc0:0x22:0:6  %d - 0x02%x\n", ret, *buf);

	*status = *buf;

	*status = *buf;

	ret = 0;

out:

	kfree(buf);

	kfree(buf);





	return ret;

	return ret;