From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Frank Ch. Eigler" <fche@redhat.com>
Subject: Re: linux-next: add utrace tree
Date: Sat, 23 Jan 2010 07:03:01 -0500
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To: Ingo Molnar <mingo@elte.hu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>, Steven Rostedt <rostedt@goodmis.org>, Fr??d??ric Weisbecker <fweisbec@gmail.com>, Arnaldo Carvalho de Melo <acme@redhat.com>, Li Zefan <lizf@cn.fujitsu.com>, Tom Zanussi <tzanussi@gmail.com>, systemtap@sources.redhat.com, dle-develop@lists.sourceforge.net, Andrew Morton <akpm@linux-foundation.org>, Stephen Rothwell <sfr@canb.auug.org.au>, Ananth N Mavinakayanahalli <ananth@in.ibm.com>, Peter Zijlstra <a.p.zijlstra@chello.nl>, Peter Zijlstra <peterz@infradead.org>, LKML <linux-kernel@vger.kernel.org>, linux-next@vger.kernel.org, "H. Peter Anvin" <hpa@zytor.com>, utrace-devel@redhat.com, Thomas Gleixner <tglx@linutronix.de>
List-Id: linux-next.vger.kernel.org

Hi -

On Sat, Jan 23, 2010 at 07:04:01AM +0100, Ingo Molnar wrote:

> [...]  Also, if any systemtap person is interested in helping us
> create a more generic filter engine out of the current ftrace filter
> engine (which is really a precursor of a safe, sandboxed in-kernel
> script engine), that would be excellent as well. [...]

Thank you for the invitation.

> More could be done - a simple C-like set of function perhaps - some minimal 
> per probe local variable state, etc. (perhaps even looping as well, with a 
> limit on number of predicament executions per filter invocation.)

Yes, at some point when such bytecode intepreter gets rich enough, one
may not need the translated-to-C means of running scripts.


> ( _Such_ a facility, could then perhaps be used to allow applications access 
>   to safe syscall sandboxing techniques: i.e. a programmable seccomp concept 
>   in essence, controlled via ASCII space filter expressions [...]
>   IMHO that would be a superior concept for security modules too [...]
>
> [...]  specific functionality with an immediately visible upside,
> with no need for opaque hooks.

This OTOH seem like rather a stretch.  If one claims that "opaque
hooks" are bad, so instead have hooks that jump not to auditable C
code but an bytecode interpreter?  And have the bytecodes be uploaded
from userspace?  How is this supposed to produce "transparency" from
the kernel/hook point of view?

- FChE