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Date:      Sat, 5 Jul 2014 21:05:52 +0300
From:      Konstantin Belousov <kostikbel@gmail.com>
To:        Julian Elischer <julian@freebsd.org>
Cc:        freebsd-fs@freebsd.org, Stefan Parvu <sparvu@systemdatarecorder.org>, FreeBSD Hackers <freebsd-hackers@freebsd.org>, Roger Pau Monn? <roger.pau@citrix.com>
Subject:   Re: Strange IO performance with UFS
Message-ID:  <20140705180552.GT93733@kib.kiev.ua>
In-Reply-To: <53B80A97.1080803@freebsd.org>
References:  <53B691EA.3070108@citrix.com> <53B69C73.7090806@citrix.com> <20140705001938.54a3873dd698080d93d840e2@systemdatarecorder.org> <53B7C616.1000702@citrix.com> <20140705095831.GO93733@kib.kiev.ua> <53B7D4DF.40301@citrix.com> <20140705112448.GQ93733@kib.kiev.ua> <53B80A97.1080803@freebsd.org>

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On Sat, Jul 05, 2014 at 10:24:23PM +0800, Julian Elischer wrote:
> On 7/5/14, 7:24 PM, Konstantin Belousov wrote:
> > This leaves the unwritten portion of the block with the garbage. I
> > believe that it is not harmful, since the only way for usermode to
> > access that garbage is through the mmap(2). The vnode_generic_getpages()
> > zeroes out parts of the page which are after EOF.
>=20
> I have vague memories of this being in a security bulletin once along=20
> the lines of "random data disclosure"  by making tons of 1 frag size=20
> files and then mmapping them.
I am not sure what do you reference there.

Might be,
http://www.freebsd.org/security/advisories/FreeBSD-SA-13:11.sendfile.asc ?

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