Re: Using ftrace/perf as a basis for generic seccomp

[Ingo Molnar <mingo@elte.hu>]

* Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> wrote:

> Hi Eric,
> 
> (2011/02/01 23:58), Eric Paris wrote:
> > On Wed, Jan 12, 2011 at 4:28 PM, Eric Paris <eparis@redhat.com> wrote:
> >> Some time ago Adam posted a patch to allow for a generic seccomp
> >> implementation (unlike the current seccomp where your choice is all
> >> syscalls or only read, write, sigreturn, and exit) which got little
> >> traction and it was suggested he instead do the same thing somehow using
> >> the tracing code:
> >> http://thread.gmane.org/gmane.linux.kernel/833556
> 
> Hm, interesting idea :)
> But why would you like to use tracing code? just for hooking?

What I suggested before was to reuse the scripting engine and the tracepoints.

I.e. the "seccomp restrictions" can be implemented via a filter expression - and the 
scripting engine could be generalized so that such 'sandboxing' code can make use of 
it.

For example, if you want to restrict a process to only allow open() syscalls to fd 4 
(a very restrictive sandbox), it could be done via this filter expression:

	'fd == 4'

etc. Note that obviously the scripting engine needs to be abstracted out somewhat - 
but this is the basic idea, to reuse the callbacks and reuse the scripting engine 
for runtime filtering of syscall parameters.

Thanks,

	Ingo