Re: Unexecutable Stack / Buffer Overflow Exploits...

[Jesse Pollard]

>IIRC, (at least) the PowerPC architecture can have both non executable
>pages (or segments?) and read-only executables pages.
>So if all executable pages are non-executable how would such exploit be possible?
>May be such a thing would break too many user space programs ?

back in the old VAX days, you could define a file containing segment
definitions - read-only, read/write, executable (but not readable) or
combinations of the three. Just include the definition (first) and link
the program. All segments would take the characteristics of the first
definition. This allowed non-executable data, non-executable stack, and
executable text, with no possibility of corrupting dataspace.

If the compiler development people had this, and the kernel program
loader supported it... and hardware support was available then there
would be no problems. The daemons linked with suitable segment
definitions would make a reasonably high barrer for hackers.

-------------------------------------------------------------------------
Jesse I Pollard, II
Email: [e-mail]

Any opinions expressed are solely my own.