Re: [EXAMPLE CODE] Parasite thread injection and TCP connectionhijacking

[Tejun Heo]

On Sat, Aug 06, 2011 at 03:00:37PM +0200, Tejun Heo wrote:
> Hello,
> 
> On Sat, Aug 06, 2011 at 08:45:28AM -0400, Andy Lutomirski wrote:
> > > 2. Decide where to inject the foreign code and save the original code
> > >    with PTRACE_PEEKDATA.  Tracer can poke any mapped area regardless
> > >    of protection flags but it can't add execution permission to the
> > >    code, so it needs to choose memory area which already has X flag
> > >    set.  The example code uses the page the %rip is in.
> > 
> > If the process is executing from the vsyscall page, then you'll
> > probably fail.  (Admittedly, this is rather unlikely, given that the
> > vsyscalls are now exactly one instruction.)  Presumably you also
> > fail if executing from a read-only MAP_SHARED mapping.
> 
> Heh, yeah, I originally thought about scanning /proc/PID/maps to look
> for the page to use but was lazy and just used %rip.  I think that
> should work.  I'll note the problem in README.

Okay, updated README.

  http://code.google.com/p/ptrace-parasite/source/browse/README

Thanks.

-- 
tejun
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