Re: HIDDEV: potential NULL dereference

From: Jiri Kosina
Date: Mon Sep 13 2010 - 11:02:38 EST


On Thu, 9 Sep 2010, anil joshi wrote:

>
>
> On Thu, Sep 9, 2010 at 7:59 PM, anil joshi <anilsjoshi123@xxxxxxxxx> wrote:
>  hid->dev.parent is "usb_interfae"  pointer is kfree  in  usb_release_interfece 
> hid_to_usb_dev(dev) accessing hid->dev.parent 
>
> I have tested this,while removing  hid device  
>
> usb_release_interfece is belonging to khubd  process 
>
> I get many use full information  from  Jiri Kosina, Markus Trippelsdorf, regarding this issue
> from http://kerneltrap.org/mailarchive/linux-kernel/2010/8/12/4606155/thread#mid-4606155
>
> To avoid  NULL deference problem 
>
> hiddev->exist is zero before usb_deregister_dev  call in  hiddev_disconnected  function there fore
> we could use
> static long hiddev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> {
>
>
>      if (hiddev->exist) {
>          hid_to_usb_dev(dev);
>        } else {
>             return -EIO
>    }
>
>
> Thanks to Markus Trippelsdorf , Jiri Kosina 

Hi Anil,

could you please send a proper patch (diff against current kernel) and a
short changelog entry with the explanation, so that I could easily
understand what you are proposing?

Thanks!

--
Jiri Kosina
SUSE Labs, Novell Inc.
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