vsyscallRe: X15 alpha release: as fast as TUX but in user space (fwd)

Pavel Machek
2001-05-11T07:04:04Z

Hi!

> > That means that for fooling closed-source statically-linked binary,
> > you now need to patch kernel. That's regression; subterfugue.org could
> > do this with normal user rights in 2.4.0.
>
> This is particularly pretty, but something that might work:
>
> 1. a "deceiver" process creates a shared memory page, populates shared
> page with appropriate magic (perhaps copying from its own magic page?)
> 2. have subterfuge unmap the magic page for the fooled process, and map in
> the shared page in its place (assumes subterfuge can insert system
> calls, instead of just modifying them)

subterfugue can insert calls just fine; just I'm not sure if vsyscall
implementation will let you unmap magic page.

> 3. deceiver periodically updates magic page

This is going to be the hard part.

--
Philips Velo 1: 1"x4"x8", 300gram, 60, 12MB, 40bogomips, linux, mutt,
details at http://atrey.karlin.mff.cuni.cz/~pavel/velo/index.html.