OpenEuphoria

Re: WinXP SP2 and inline machine code calling

• Posted by CoJaBo <cojabo at suscom.net> Sep 15, 2004
• 443 views

Tommy Carlier wrote:
> 
> unknown wrote:
> > I  haven't  tried  SP2, and possibly never, but SP2 has Data Execution
> > Prevention <a href="http://fype.com/sp2dep">http://fype.com/sp2dep</a>
> > 
> > Will it be preventing this kind of code execution?
> > (because the code will be executed from data area, CMIIW)
> > 
> > 
> > (taken from bit.e)
> > poke(SHL_SPACE, {
> >      -- first int argument is at stack offset +4, 2nd int is at +8
> >      -- returns a *signed* 32-bit number
> >      #8B, #44, #24, #04,      -- mov  eax, [esp+4]
> >      #8A, #4C, #24, #08,      -- mov  cl,  [esp+8]
> >      #D3, #E0,                -- shl  eax, cl
> >      #C2, #08, #00            -- ret  8  -- pop 8 bytes off the stack
> >     })
> > 
> > SHIFT_LEFT = define_c_func("", SHL_SPACE, {C_INT, C_INT}, C_INT)
> 
> Only if your CPU has a mechanism to block execution from a data area. And only
> the
> very recent CPUs

I am getting a computer with one of these
(a replacement for my old laptop that ignited and HP won't fix it),
I'll test it.
Should be here early next month.

> have such a mechanism. But that's an interesting and perhaps disturbing
> thought, given your example.
> 
> --
> tommy online: <a
> href="http://users.telenet.be/tommycarlier">http://users.telenet.be/tommycarlier</a>
> tommy.blog: <a
> href="http://tommycarlier.blogspot.com">http://tommycarlier.blogspot.com</a>
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>