mfd: dln2: More sanity checking for endpoints

It is not enough to check for the number of endpoints.
The types must also be correct.

Reported-and-tested-by: syzbot+48a2851be24583b864dc@syzkaller.appspotmail.com
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

diff --git a/drivers/mfd/dln2.c b/drivers/mfd/dln2.c
index 381593f..7841c11 100644 (file)
--- a/drivers/mfd/dln2.c
+++ b/drivers/mfd/dln2.c
@@ -722,6 +722,8 @@ static int dln2_probe(struct usb_interface *interface,
                      const struct usb_device_id *usb_id)
 {
        struct usb_host_interface *hostif = interface->cur_altsetting;
+       struct usb_endpoint_descriptor *epin;
+       struct usb_endpoint_descriptor *epout;
        struct device *dev = &interface->dev;
        struct dln2_dev *dln2;
        int ret;
@@ -731,12 +733,19 @@ static int dln2_probe(struct usb_interface *interface,
            hostif->desc.bNumEndpoints < 2)
                return -ENODEV;
 
+       epin = &hostif->endpoint[0].desc;
+       epout = &hostif->endpoint[1].desc;
+       if (!usb_endpoint_is_bulk_out(epout))
+               return -ENODEV;
+       if (!usb_endpoint_is_bulk_in(epin))
+               return -ENODEV;
+
        dln2 = kzalloc(sizeof(*dln2), GFP_KERNEL);
        if (!dln2)
                return -ENOMEM;
 
-       dln2->ep_out = hostif->endpoint[0].desc.bEndpointAddress;
-       dln2->ep_in = hostif->endpoint[1].desc.bEndpointAddress;
+       dln2->ep_out = epout->bEndpointAddress;
+       dln2->ep_in = epin->bEndpointAddress;
        dln2->usb_dev = usb_get_dev(interface_to_usbdev(interface));
        dln2->interface = interface;
        usb_set_intfdata(interface, dln2);