* Ingo Molnar <[EMAIL PROTECTED]> wrote: > > > This is the seccomp patch ported to 2.6.11-rc1-bk8, that I need for > > > Cpushare (until trusted computing will hit the hardware market). > > > [...] > > > > why do you need any kernel code for this? This seems to be a limited > > ptrace implementation: restricting untrusted userspace code to only be > > able to exec read/write/sigreturn. > > > > So this patch, unless i'm missing something, duplicates in essence what > > ptrace can do [...] > > there's one thing ptrace wont do: if the ptrace parent dies > unexpectedly and the child was 'running' (there is a small window > where the child might not be stopped and where this may happen) then > the child can get runaway. While i think this is theoretical (UML > doesnt suffer from this problem), it is simple to fix - find below a > proof-of-concept patch that introduces PTRACE_ATTACH_JAIL - ptraced > children can never escape out of such a jail. (barely tested - but you > get the idea.)
maybe this could even be fit into existing ptrace semantics, without any need for PTRACE_ATTACH_JAIL. What we need is to catch the case where a ptraced child is running (i.e. the signal_wake_up() has already been done, and the parent is waiting for the child to stop again), and the ptrace parent is killed unexpectedly. Would it be a correct fix to just unconditionally stop the child in this case (and leave it hanging in such a state)? Or to kill it right away? Ingo - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/