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

[Pavel Machek <pavel@suse.cz>]

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.

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