Date: Wed, 5 Mar 2008 13:43:12 -0800
From: Joe Buck <Joe.Buck@synopsys.COM>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Richard Guenther <richard.guenther@gmail.com>, Michael Matz <matz@suse.de>,
       Jan Hubicka <hubicka@ucw.cz>, Aurelien Jarno <aurelien@aurel32.net>,
       linux-kernel@vger.kernel.org, gcc@gcc.gnu.org
Subject: Re: RELEASE BLOCKER: Linux doesn't follow x86/x86-64 ABI wrt direction  flag
Message-ID: <20080305214311.GD17267@synopsys.com>
References: <47CEC3AA.6080709@zytor.com> <20080305195834.GA17267@synopsys.com> <20080305202319.GA17053@volta.aurel32.net> <Pine.LNX.4.64.0803052133400.20583@wotan.suse.de> <20080305204234.GB17267@synopsys.com> <20080305204945.GB14011@atrey.karlin.mff.cuni.cz> <Pine.LNX.4.64.0803052158270.20583@wotan.suse.de> <20080305212005.GC17267@synopsys.com> <84fc9c000803051332q2f2eedeej7d3c0509e698cabf@mail.gmail.com> <47CF11D6.7070901@zytor.com>
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On Wed, Mar 05, 2008 at 01:34:14PM -0800, H. Peter Anvin wrote:
> Richard Guenther wrote:
> >
> >We didn't yet run into this issue and build openSUSE with 4.3 since more 
> >than
> >three month.
> >
> 
> Well, how often do you take a trap inside an overlapping memmove()?

Also, would it be possible to produce an exploit?  If you can get string
instructions to work "the wrong way", you might be able to overwrite data.

"We haven't seen a problem" isn't the right answer.  Can someone
deliberately *create* a problem?

And if we aren't sure, we should err on the side of safety.


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