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From: Jeff Garzik <jeff@garzik.org>
To: Jens Axboe <jens.axboe@oracle.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
	Daniel Drake <dsd@gentoo.org>,
	linux list <linux-kernel@vger.kernel.org>,
	linux-ide@vger.kernel.org
Subject: Re: "Fix ATAPI transfer lengths" causes CD writing regression
Date: Wed, 31 Oct 2007 12:05:40 -0400	[thread overview]
Message-ID: <4728A7D4.8050008@garzik.org> (raw)
In-Reply-To: <20071031122639.GN5059@kernel.dk>

Jens Axboe wrote:
> Right, that's of course problematic... There has to be a way to recover
> that situation though, or you can't export any user command issue
> facility.

You cannot hope to handle all possible effects arising from an app 
providing an invalid sg header / cdb.

Once you start talking "recovery" you are already screwed:  we are 
talking about low-level hardware commands that are passed straight to 
the hardware.  It is trivial to lock up hardware, brick hardware, and 
corrupt data at that level.


If this is NOT a privileged app, we must update the command validation 
to ensure that invalid commands are not transported to the hardware.

If this is a privileged app, our work is done.  Fix the app.  We gave 
root rope, and he took it.


I even venture to say that "accept anything, clean up afterwards" is 
/impossible/ to implement, in addition to being dangerous.

	Jeff



  reply	other threads:[~2007-10-31 16:05 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-10-30 15:14 "Fix ATAPI transfer lengths" causes CD writing regression Daniel Drake
2007-10-30 15:34 ` Alan Cox
2007-10-30 17:45   ` Daniel Drake
2007-10-30 18:26     ` Frans Pop
2007-10-30 19:01     ` Alan Cox
2007-10-30 19:21       ` Daniel Drake
2007-10-31 11:49         ` Alan Cox
2007-10-31 11:57           ` Jens Axboe
2007-10-31 12:20             ` Jeff Garzik
2007-10-31 12:26               ` Jens Axboe
2007-10-31 16:05                 ` Jeff Garzik [this message]
2007-10-31 16:29                   ` Alan Cox
2007-10-31 16:34                   ` Daniel Drake
2007-10-31 17:55                   ` Jens Axboe
2007-11-01  0:40               ` Tejun Heo
2007-11-01  7:24                 ` Tejun Heo
2007-11-01 10:50                 ` Alan Cox
2007-10-31 12:49             ` Alan Cox
2007-11-01  9:48             ` Jeff Garzik
2007-11-01 10:53               ` Alan Cox
2007-11-01 11:09                 ` Jeff Garzik
2007-11-01 14:15                   ` Alan Cox
2007-11-01 15:33                     ` Daniel Drake
2007-11-01 15:57                       ` Alan Cox
2007-11-01 16:06                         ` Tejun Heo
2007-11-01 16:04                       ` Tejun Heo
2007-11-02 21:19                         ` Daniel Drake
2007-11-03  1:17                           ` Tejun Heo
2007-11-03 12:34                             ` Jeff Garzik
2007-11-03 20:02                             ` Daniel Drake
2007-11-04  0:07                               ` Tejun Heo
2007-11-04  4:02                                 ` Albert Lee
2007-11-04 23:42                                   ` Alan Cox
2007-11-05  0:05                                     ` Tejun Heo
2007-11-05 13:03                                       ` Alan Cox
2007-11-06 10:18                                         ` Tejun Heo
2007-11-06 12:48                                           ` Alan Cox
2007-11-05  0:15                                 ` Daniel Drake
2007-11-02 17:58                       ` Jeff Garzik
2007-10-30 16:02 ` Jeff Garzik
2007-10-30 16:10   ` Alan Cox

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