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From: Greg KH <gregkh@linuxfoundation.org>
To: sathyanarayanan.kuppuswamy@linux.intel.com
Cc: johan@kernel.org, linux-usb@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 1/1] USB: serial: Add boundry check for read_urbs array access
Date: Wed, 7 Mar 2018 12:58:40 -0800	[thread overview]
Message-ID: <20180307205840.GA6242@kroah.com> (raw)
In-Reply-To: <f48feae7582a5669422066b4821a9e310eebc9ba.1520454192.git.sathyanarayanan.kuppuswamy@linux.intel.com>

On Wed, Mar 07, 2018 at 12:23:56PM -0800, sathyanarayanan.kuppuswamy@linux.intel.com wrote:
> From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
> 
> In usb_serial_generic_submit_read_urb() function we are accessing the
> port->read_urbs array without any boundry checks. This might lead to
> kernel panic when index value goes above array length.
> 
> One posible call path for this issue is,
> 
> usb_serial_generic_read_bulk_callback()
> {
>  ...
>  if (!port->throttled) {
> 	usb_serial_generic_submit_read_urb(port, i, GFP_ATOMIC);
>  ...
> }

How does i ever get to be greater than the array size here in this
function?  It directly came from looking in that array in the first
place :)

So I don't see why your check is needed, what other code path would ever
call this function in a way that the bounds check would be needed?

thanks,

greg k-h

  reply	other threads:[~2018-03-07 20:58 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-07 20:23 [PATCH v1 1/1] USB: serial: Add boundry check for read_urbs array access sathyanarayanan.kuppuswamy
2018-03-07 20:58 ` Greg KH [this message]
2018-03-07 21:41   ` sathyanarayanan kuppuswamy
2018-03-08  8:54     ` Oliver Neukum
2018-03-08 23:29       ` sathyanarayanan kuppuswamy
2018-03-08 23:43         ` Greg KH
2018-03-09  0:34           ` sathyanarayanan kuppuswamy
2018-03-08 14:01     ` Greg KH

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