On Tue, Sep 17, 2013 at 10:01:23AM -0300, Eduardo Otubo wrote: > > > On 09/11/2013 01:49 PM, Daniel P. Berrange wrote: > >On Wed, Sep 11, 2013 at 12:45:54PM -0400, Corey Bryant wrote: > >> > >> > >>On 09/06/2013 03:21 PM, Eduardo Otubo wrote: > >>>New command line options for the seccomp blacklist feature: > >>> > >>> $ qemu -sandbox on[,strict=<on|off>] > >>> > >>>The strict parameter will turn on or off the new system call blacklist > >> > >>I mentioned this before but I'll say it again since I think it needs > >>to be discussed. Since this regresses support (it'll prevent -net > >>bridge and -net tap from using execv) the concern I have with the > >>strict=on|off option is whether or not we will have the flexibility > >>to modify the blacklist once QEMU is released with this support. Of > >>course we should be able to add more syscalls to the blacklist as > >>long as they don't regress QEMU functionality. But if we want to > >>add a syscall that does regress QEMU functionality, I think we'd > >>have to add a new command line option, which doesn't seem desirable. > >> > >>So a more flexible approach may be necessary. Maybe the blacklist > >>should be passed on the command line, which would enable it to be > >>defined by libvirt and passed to QEMU. I know Paul is working on > >>something for libvirt so maybe that answers this question. > > Paul, what exactly are you planning to add to libvirt? I'm not a big > fan of using qemu command line to pass syscalls for blacklist as > arguments, but I can't see other way to avoid problems (like -net > bridge / -net tap) from happening.
IMHO, if libvirt is enabling seccomp, then making all possible cli args work is a non-goal. If there are things which require privileges seccomp is blocking, then libvirt should avoid using them. eg by making use of FD passing where appropriate to reduce privileges qemu needs. Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|
