Re: Compat 32-bit syscall entry from 64-bit task!?

[Oleg Nesterov]

On 01/23, Indan Zupancic wrote:
>
> On Sat, January 21, 2012 02:23, Jamie Lokier wrote:
> >
> > (Fwiw, two other issues with arch-independent ptrace have come up in this
> > thread, which ought to be fairly easy to fix:
> >    - If tracer dies, tracee is free to continue running.  For security
> >      tracers, and would be useful for strace as well, it would be good
> >      to have an option to SIGKILL the tracee if tracer dies.
>
> It should be easy to add a PTRACE_O_SIGKILL_ON_DEATH option.

Yes, this looks simple.

> >    - Can't abort or change an unwanted syscall if the process receives
> >      SIGKILL as it's about to start a syscall (which will be its last).)
>
> This is very important for any syscall filtering/control via ptrace, otherwise
> SIGKILL becomes a security problem. Oleg had a patch for that:

OK, I'll send this patch after some testing. Although it looks trivial.

Oleg.

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