Re: seccomp for 2.6.11-rc1-bk8

[daw@taverner.cs.berkeley.edu (David Wagner)]

Chris Wright  wrote:
>Only difference is in number of context switches, and number of running
>processes (and perhaps ease of determining policy for which syscalls
>are allowed).  Although it's not really seccomp, it's just restricted
>syscalls...

There is a simple tweak to ptrace which fixes that: one could add an
API to specify a set of syscalls that ptrace should not trap on.  To get
seccomp-like semantics, the user program could specify {read,write}, but
if the user program ever wants to change its policy, it could change that
set.  Solaris /proc (which is what is used for tracing) has this feature.
I coded up such an extension to ptrace semantics a long time ago, and
it seemed to work fine for me, though of course I am not a ptrace expert.

I don't know whether ptrace + this tweak is a better idea than seccomp.
It is just another option out there that achieves similar functionality.