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From: Clemens Ladisch <clemens-P6GI/4k7KOmELgA04lAiVw@public.gmane.org>
To: Stefan Richter
	<stefanr-MtYdepGKPcBMYopoZt5u/LNAH6kLmebB@public.gmane.org>,
	linux1394-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org
Cc: linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	David Ramos <daramos-FGKo4X94FMn2fBVCVOL8/A@public.gmane.org>
Subject: Re: [PATCH RFC v1b] firewire: cdev: prevent kernel stack leaking into ioctl arguments
Date: Tue, 11 Nov 2014 19:22:10 +0100	[thread overview]
Message-ID: <546253D2.9050400@ladisch.de> (raw)
In-Reply-To: <20141111171644.7f6b17c7@kant>

Stefan Richter wrote:
> This fix simply always null-initializes the entire ioctl argument buffer
> regardless of the actual length of expected user input.  That is, a
> runtime overhead of memset(..., 40) is added to each firewirew-cdev
> ioctl() call.

This part of the stack is most likely to be already in the cache.


Regards,
Clemens

WARNING: multiple messages have this Message-ID (diff)
From: Clemens Ladisch <clemens@ladisch.de>
To: Stefan Richter <stefanr@s5r6.in-berlin.de>,
	linux1394-devel@lists.sourceforge.net
Cc: linux-api@vger.kernel.org, linux-kernel@vger.kernel.org,
	David Ramos <daramos@stanford.edu>
Subject: Re: [PATCH RFC v1b] firewire: cdev: prevent kernel stack leaking into ioctl arguments
Date: Tue, 11 Nov 2014 19:22:10 +0100	[thread overview]
Message-ID: <546253D2.9050400@ladisch.de> (raw)
In-Reply-To: <20141111171644.7f6b17c7@kant>

Stefan Richter wrote:
> This fix simply always null-initializes the entire ioctl argument buffer
> regardless of the actual length of expected user input.  That is, a
> runtime overhead of memset(..., 40) is added to each firewirew-cdev
> ioctl() call.

This part of the stack is most likely to be already in the cache.


Regards,
Clemens

  reply	other threads:[~2014-11-11 18:22 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <55D28623-C1C7-47D2-9638-0B8FD0733C48@stanford.edu>
     [not found] ` <20141111010340.3329bbd7@kant>
     [not found]   ` <20141111130143.2ff3d42e@kant>
2014-11-11 16:13     ` [PATCH] drivers/firewire: fix use/leak of uninitialized stack memory in dispatch_ioctl() Stefan Richter
2014-11-11 16:13       ` Stefan Richter
2014-11-11 16:15       ` [PATCH RFC v1a] firewire: cdev: prevent kernel stack leaking into ioctl arguments Stefan Richter
2014-11-11 16:15         ` Stefan Richter
2014-11-11 16:16       ` [PATCH RFC v1b] " Stefan Richter
2014-11-11 16:16         ` Stefan Richter
2014-11-11 18:22         ` Clemens Ladisch [this message]
2014-11-11 18:22           ` Clemens Ladisch

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