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From: "Dan Magenheimer" <dan.magenheimer@oracle.com>
To: "Xen-Devel (E-mail)" <xen-devel@lists.xensource.com>
Subject: Is exposing shared_info to user-land secure?
Date: Fri, 1 Aug 2008 10:13:39 -0600	[thread overview]
Message-ID: <20080801101339906.00000008444@djm-pc> (raw)

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Is it "safe" in a paravirtualized guest to expose shared_info
(at least read-only) to user-land?  That is, is there data
in shared_info that could be used by a malicious program to
compromise a guest OS (ignoring very complex side-channel
attacks anyway)?

We have apps that constantly do various time syscalls (e.g.
to gettimeofday()) and I'm thinking if vcpu_info(cpu)->time_info
was directly readable by an enterprise app, it could do
the time calculations itself and save the syscall overhead.

Comments?

Thanks,
Dan

===================================
Thanks... for the memory
I really could use more / My throughput's on the floor
The balloon is flat / My swap disk's fat / I've OOM's in store
Overcommitted so much
(with apologies to the late great Bob Hope)

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             reply	other threads:[~2008-08-01 16:13 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-08-01 16:13 Dan Magenheimer [this message]
2008-08-01 17:24 ` Is exposing shared_info to user-land secure? Keir Fraser
2008-08-01 20:35   ` Jeremy Fitzhardinge
2008-08-01 20:31 ` Jeremy Fitzhardinge

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