On Wed, Mar 16, 2016 at 02:23:33PM +0100, Oliver Neukum wrote:
> An attack using the lack of sanity checking in probe
> is known. This patch checks for the existance of a
> second port.
> CVE-2016-3136
>
> Signed-off-by: Oliver Neukum <ONeukum@xxxxxxxx>
> CC: stable@xxxxxxxxxxxxxxx
> ---
> drivers/usb/serial/mct_u232.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/usb/serial/mct_u232.c b/drivers/usb/serial/mct_u232.c
> index fd707d6..d6a36b1 100644
> --- a/drivers/usb/serial/mct_u232.c
> +++ b/drivers/usb/serial/mct_u232.c
> @@ -378,6 +378,10 @@ static int mct_u232_port_probe(struct usb_serial_port *port)
> {
> struct mct_u232_private *priv;
>
> + /* check first to simplify error handling */
> + if (!port->serial->port[1])
> + return -ENODEV;
> +
This check is not sufficient as the second port's interrupt-in urb is
also unconditionally dereferenced below. Care to fix that up?
Ideally the existence of a second interrupt-in urb should have been
verified already at interface probe. But we can clean that up later.
> priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> if (!priv)
> return -ENOMEM;
Thanks,
Johan
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