Messages in this thread | | | Date | Wed, 7 Oct 2009 11:44:19 +0200 | From | Pavel Machek <> | Subject | Re: [PATCH] x86-64: don't leak kernel register values to 32-bit processes |
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Hi!
> While 32-bit processes can't directly access R8...R15, they can gain > access to these registers by temporarily switching themselves into > 64-bit mode. Therefore, registers not preserved anyway by called C > functions (i.e. R8...R11) must be cleared prior to returning to user > mode.
How can userspace "temporarily switch itself" to 64bit mode?
Such ability would lead to very interesting behaviour on 32-bit kernel, I'd say...
-- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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