On Sat, Feb 27, 2010 at 12:20:35PM -0500, Alan Stern wrote:
> On Fri, 26 Feb 2010, Greg KH wrote:
>
> > Hm, so it's back to the original idea of just doing a kzalloc of the
> > initial buffer, that should solve the problem that Marcus found.
> >
> > I'll go dig that back up and if you could test it, that would be most
> > appreciated.
>
> Here's a better solution. In theory we could copy just the individual
> packets from within the transfer buffer, but that would probably take
> longer than simply copying the whole buffer.
>
> (This was a little hasty; I haven't even compile-tested the patch.
> Some small fixes may be needed.)
Markus, did you test this patch out?
thanks,
greg k-h
> -----------------------------------------------------------------------
>
> This patch fixes a bug in the way isochronous input data is returned
> to userspace for usbfs transfers. The entire buffer must be copied,
> not just the first actual_length bytes, because the individual packets
> will be discontiguous if any of them are short.
>
> Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
> CC: stable <stable@xxxxxxxxxx>
>
> ---
>
> Index: usb-2.6/drivers/usb/core/devio.c
> ===================================================================
> --- usb-2.6.orig/drivers/usb/core/devio.c
> +++ usb-2.6/drivers/usb/core/devio.c
> @@ -1176,6 +1176,13 @@ static int proc_do_submiturb(struct dev_
> free_async(as);
> return -ENOMEM;
> }
> + /* Isochronous input data may end up being discontiguous
> + * if some of the packets are short. Clear the buffer so
> + * that the gaps don't leak kernel data to userspace.
> + */
> + if (is_in && uurb->type == USBDEVFS_URB_TYPE_ISO)
> + memset(as->urb->transfer_buffer, 0,
> + uurb->buffer_length);
> }
> as->urb->dev = ps->dev;
> as->urb->pipe = (uurb->type << 30) |
> @@ -1312,10 +1319,14 @@ static int processcompl(struct async *as
> void __user *addr = as->userurb;
> unsigned int i;
>
> - if (as->userbuffer && urb->actual_length)
> - if (copy_to_user(as->userbuffer, urb->transfer_buffer,
> - urb->actual_length))
> + if (as->userbuffer && urb->actual_length) {
> + if (urb->number_of_packets > 0) /* Isochronous */
> + i = urb->transfer_buffer_length;
> + else /* Non-Isoc */
> + i = urb->actual_length;
> + if (copy_to_user(as->userbuffer, urb->transfer_buffer, i))
> goto err_out;
> + }
> if (put_user(as->status, &userurb->status))
> goto err_out;
> if (put_user(urb->actual_length, &userurb->actual_length))
--
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
