On Wed, Nov 23, 2016 at 05:35:45PM +0100, Greg KH wrote: > On Wed, Nov 23, 2016 at 05:17:35PM +0100, Wolfgang Wilhelm wrote: > > Thankyou very much for the really fast answer. > > > > I don't get any error messages and I can communicate with > > the driver for the second device via ioctrl and write functions, > > i.e. write registers and read registers via the RBUF ioctrl function, > > only the read function for the second device does not work, > > i.e. no data is obtained from the mcs6_read function for the > > second device. > > Hm, let me go look at the driver again, maybe something's odd with it. I don't see anything odd with your read function, is it just timing out? Have you tried doing read/writes from userspace with libusb and that works correctly? > > Which security problems do you see in the code? > > No checking that the values given to you by userspace are actually valid > and within "sane" ranges :) Oh, also your ioctl types need to be better specified than "int" as that doesn't make much sense with 64bit kernels and a 32bit userspace. You need to use types like __u32 in order to make sure that works correctly in all situations. thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html