Re: RELEASE BLOCKER: Linux doesn't follow x86/x86-64 ABI wrt direction flag

From: Richard Guenther
Date: Wed Mar 05 2008 - 16:45:28 EST


On Wed, Mar 5, 2008 at 10:43 PM, Joe Buck <Joe.Buck@xxxxxxxxxxxx> wrote:
>
> 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.

Oh, you mean releasing a kernel security update? ;) What does ICC or
other compilers do?

Richard.
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