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From: Adrian Cox <adrian@humboldt.co.uk>
To: Andrew Morton <akpm@zip.com.au>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Filling holes in ext2
Date: Wed, 22 Aug 2001 19:59:57 +0100	[thread overview]
Message-ID: <3B84012D.1010303@humboldt.co.uk> (raw)
In-Reply-To: <3B83E9FD.6020801@humboldt.co.uk> <3B83FB3F.A0BDC056@zip.com.au>

Andrew Morton wrote:
> Adrian Cox wrote:

>>Can this actually be exploited?  I assume the test on __copy_from_user()
>>is there in case another thread changes memory mappings while
>>generic_file_write() is running. My attempts to do this haven't yet
>>succeeded.
> I'd expect it to occur if you simply pass an unmapped address
> to write()?

No, because the first thing generic_file_write does is an access_ok() 
check. It can only happen if the permissions change during the function. 
That's why it's hard to exploit for real.

-- 
Adrian Cox   http://www.humboldt.co.uk/


  reply	other threads:[~2001-08-22 19:00 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-08-22 17:21 Adrian Cox
2001-08-22 18:34 ` Andrew Morton
2001-08-22 18:59   ` Adrian Cox [this message]
2001-08-23 17:22   ` Adrian Cox
2001-08-23 17:46     ` Andrew Morton
2001-08-23 19:17       ` Adrian Cox
2001-08-23 19:23         ` Alan Cox
2001-08-23 19:41         ` Andrew Morton
2001-08-23 21:21           ` Adrian Cox
2001-08-23 17:47     ` Alan Cox

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