Date: Wed, 2 Feb 2011 13:26:20 +0100
From: Ingo Molnar <mingo@elte.hu>
To: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Eric Paris <eparis@parisplace.org>, Eric Paris <eparis@redhat.com>,
        linux-kernel@vger.kernel.org, agl@google.com, fweisbec@gmail.com,
        tzanussi@gmail.com, Jason Baron <jbaron@redhat.com>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        2nddept-manager@sdl.hitachi.co.jp
Subject: Re: Using ftrace/perf as a basis for generic seccomp
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* 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
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