linux-kernel - Re: [PATCH] usb: Clear both buffers when clearing a control transfer TT buffer.

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Mon, 1 Jul 2013 16:41:17 -0400 (EDT)
From:	Alan Stern <stern@...land.harvard.edu>
To:	William Gulland <wgulland@...gle.com>
cc:	Sarah Sharp <sarah.a.sharp@...ux.intel.com>,
	Lan Tianyu <tianyu.lan@...el.com>,
	Ming Lei <ming.lei@...onical.com>, <linux-usb@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] usb: Clear both buffers when clearing a control transfer
 TT buffer.

On Thu, 27 Jun 2013, William Gulland wrote:

>     Control transfers have both IN and OUT (or SETUP) packets, so when
>     clearing TT buffers for a control transfer it's necessary to send
>     two HUB_CLEAR_TT_BUFFER requests to the hub.
> 
> Signed-off-by: William Gulland <wgulland@...gle.com>
> ---
>  drivers/usb/core/hub.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index feef935..868ad74 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -668,6 +668,15 @@ resubmit:
>  static inline int
>  hub_clear_tt_buffer (struct usb_device *hdev, u16 devinfo, u16 tt)
>  {
> +	/* Need to clear both directions for control ep */
> +	if (((devinfo >> 11) & USB_ENDPOINT_XFERTYPE_MASK) ==
> +			USB_ENDPOINT_XFER_CONTROL) {
> +		int status = usb_control_msg(hdev, usb_sndctrlpipe(hdev, 0),
> +				HUB_CLEAR_TT_BUFFER, USB_RT_PORT,
> +				devinfo ^ 0x8000, tt, NULL, 0, 1000);
> +		if (status)
> +			return status;
> +	}
>  	return usb_control_msg(hdev, usb_sndctrlpipe(hdev, 0),
>  			       HUB_CLEAR_TT_BUFFER, USB_RT_PORT, devinfo,
>  			       tt, NULL, 0, 1000);

Well, this won't hurt much.  And since it does seem to fix a hardware
problem,

Acked-by: Alan Stern <stern@...land.harvard.edu>

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/