Re: [RFC,PATCH 1/2] seccomp_filters: system call filtering using BPF

[Jamie Lokier]

Steven Rostedt wrote:
> On Thu, 2012-01-12 at 17:14 +0100, Oleg Nesterov wrote:
> 
> > May be this needs something like LSM_UNSAFE_SECCOMP, or perhaps
> > cap_bprm_set_creds() should take seccomp.mode == 2 into account, I dunno.
> > 
> > OTOH, currently seccomp.mode == 1 doesn't allow to exec at all.
> 
> I've never used seccomp, so I admit I'm totally ignorant on this topic.
> 
> But looking at seccomp from the outside, the biggest advantage to this
> would be the ability for normal processes to be able to limit tasks it
> kicks off. If I want to run a task in a sandbox, I don't want to be root
> to do so.
> 
> I guess a web browser doesn't perform an exec to run java programs.

Actually it does.  Firefox on Linux forks and execs the Java VM.
Same for Flash, using "plugin-container".

> But it would be nice if I could execute something from the command
> line that I could run in a sand box.

You can do this now, using ptrace().  It's horrible, but half of the
horribleness is needing to understand machine-dependent registers,
which this new patch doesn't address.  (The other half is a ton of
undocumented but important ptrace() behaviours on Linux.)

-- Jamie
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