USB: uss720: fix NULL-deref at probe

BugLink: http://bugs.launchpad.net/bugs/1677589
commit f259ca3eed6e4b79ac3d5c5c9fb259fb46e86217 upstream.

Make sure to check the number of endpoints to avoid dereferencing a
NULL-pointer or accessing memory beyond the endpoint array should a
malicious device lack the expected endpoints.

Note that the endpoint access that causes the NULL-deref is currently
only used for debugging purposes during probe so the oops only happens
when dynamic debugging is enabled. This means the driver could be
rewritten to continue to accept device with only two endpoints, should
such devices exist.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

diff --git a/drivers/usb/misc/uss720.c b/drivers/usb/misc/uss720.c
index 356d312add57793aa92587571d0b398264166a25..9ff66525924eab3b4881dfb66f773204c3c8801d 100644 (file)
--- a/drivers/usb/misc/uss720.c
+++ b/drivers/usb/misc/uss720.c
@@ -708,6 +708,11 @@ static int uss720_probe(struct usb_interface *intf,
 
        interface = intf->cur_altsetting;
 
+       if (interface->desc.bNumEndpoints < 3) {
+               usb_put_dev(usbdev);
+               return -ENODEV;
+       }
+
        /*
         * Allocate parport interface 
         */