linux-kernel - Re: [PACTH v2] cdc-wdm: Clear read pipeline in case of error

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

Date:	Tue, 09 Aug 2016 14:18:19 +0200
From:	Oliver Neukum <oneukum@...e.com>
To:	robert.foss@...labora.com
Cc:	Ben Chan <benchan@...omium.org>,
	Prathmesh Prabhu <pprabhu@...omium.org>,
	Guenter Roeck <groeck@...gle.com>, gregkh@...uxfoundation.org,
	linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org
Subject: Re: [PACTH v2] cdc-wdm: Clear read pipeline in case of error

On Mon, 2016-08-08 at 11:48 -0400, robert.foss@...labora.com wrote:
> From: Robert Foss <robert.foss@...labora.com>
> 
> Implemented queued response handling. This queue is processed every time the
> WDM_READ flag is cleared.
> 
> In case of a read error, userspace may not actually read the data, since the
> driver returns an error through wdm_poll. After this, the underlying device may
> attempt to send us more data, but the queue is not processed. While userspace is
> also blocked, because the read error is never cleared.
> 
> After this patch, we proactively process the queue on a read error. If there was
> an outstanding response to handle, that will clear the error (or go through the
> same logic again, if another read error occurs). If there was no outstanding
> response, this will bring the queue size back to 0, unblocking a future response
> from the underlying device.
> 
> Tested-by: Robert Foss <robert.foss@...labora.com>
> Signed-off-by: Robert Foss <robert.foss@...labora.com>
Acked-by: Oliver Neukum <oneukum@...e.com>