From: Andrea Arcangeli <andrea@novell.com>
To: Helge Hafting <helge.hafting@hist.no>
Cc: William Lee Irwin III <wli@holomorphy.com>,
Andrew Morton <akpm@osdl.org>,
linux-kernel@vger.kernel.org, an.li.wang@intel.com
Subject: Re: truncate shows non zero data beyond the end of the inode with MAP_SHARED
Date: Thu, 16 Sep 2004 16:26:38 +0200 [thread overview]
Message-ID: <20040916142638.GW15426@dualathlon.random> (raw)
In-Reply-To: <4149539D.9070001@hist.no>
On Thu, Sep 16, 2004 at 10:49:33AM +0200, Helge Hafting wrote:
> Could this "garbage" possibly be confidential data?
I don't buy much in this theory.
> I.e. one user repeatedly makes and mmaps a 1-byte file,
> extends it to 4k, and looks at the 4095 bytes of "garbage".
> Maybe he finds some "interesting stuff" when someone else's
> confidential file just got dropped from pagecache
> so he could mmap this 1-byte file?
the old data got flushed below the i_size anyways, it sounds very
strange that confidential data is present only over the i_size and not
below the i_size, and if this guy has confidential data below the i_size
then it'd better memset the whole page. And in theory nobody should touch
the data over the i_size even if mmap allows to map it.
next prev parent reply other threads:[~2004-09-16 14:37 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-09-15 12:29 Andrea Arcangeli
2004-09-15 12:46 ` Alan Cox
2004-09-15 21:01 ` William Lee Irwin III
2004-09-15 21:55 ` Andrew Morton
2004-09-15 22:00 ` William Lee Irwin III
2004-09-15 22:08 ` Andrea Arcangeli
2004-09-16 8:49 ` Helge Hafting
2004-09-16 14:26 ` Andrea Arcangeli [this message]
2004-09-17 13:49 ` Helge Hafting
2004-09-17 13:52 ` Andrea Arcangeli
2004-09-17 13:54 ` William Lee Irwin III
2004-09-15 22:04 ` Andrea Arcangeli
2004-09-15 21:58 ` Andrea Arcangeli
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