From: Oliver Neukum Date: Thu, 31 Mar 2016 16:04:24 +0000 (-0400) Subject: USB: mct_u232: add sanity checking in probe X-Git-Tag: firefly_0821_release~176^2~4^2~50^2~152 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=9deac9454b7a5643a09829f4731276cea6697b72;p=firefly-linux-kernel-4.4.55.git USB: mct_u232: add sanity checking in probe commit 4e9a0b05257f29cf4b75f3209243ed71614d062e upstream. An attack using the lack of sanity checking in probe is known. This patch checks for the existence of a second port. CVE-2016-3136 Signed-off-by: Oliver Neukum [johan: add error message ] Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/usb/serial/mct_u232.c b/drivers/usb/serial/mct_u232.c index fd707d6a10e2..89726f702202 100644 --- a/drivers/usb/serial/mct_u232.c +++ b/drivers/usb/serial/mct_u232.c @@ -376,14 +376,21 @@ static void mct_u232_msr_to_state(struct usb_serial_port *port, static int mct_u232_port_probe(struct usb_serial_port *port) { + struct usb_serial *serial = port->serial; struct mct_u232_private *priv; + /* check first to simplify error handling */ + if (!serial->port[1] || !serial->port[1]->interrupt_in_urb) { + dev_err(&port->dev, "expected endpoint missing\n"); + return -ENODEV; + } + priv = kzalloc(sizeof(*priv), GFP_KERNEL); if (!priv) return -ENOMEM; /* Use second interrupt-in endpoint for reading. */ - priv->read_urb = port->serial->port[1]->interrupt_in_urb; + priv->read_urb = serial->port[1]->interrupt_in_urb; priv->read_urb->context = port; spin_lock_init(&priv->lock);