Re: [libvirt] [Qemu-devel] spec, RFC: TLS support for NBD

On Mon, Oct 20, 2014 at 08:58:14AM +0100, Daniel P. Berrange wrote: > On Sat, Oct 18, 2014 at 07:33:22AM +0100, Richard W.M. Jones wrote: > > On Sat, Oct 18, 2014 at 12:03:23AM +0200, Wouter Verhelst wrote: > > > Hi all, > > > > > > (added rjones from nbdkit fame -- hi there) > > > > [I'm happy to implement whatever you come up with, but I've added > > Florian Weimer to CC who is part of Red Hat's product security group] > > > > > So I think the following would make sense to allow TLS in NBD. > > > > > > This would extend the newstyle negotiation by adding two options (i.e., > > > client requests), one server reply, and one server error as well as > > > extend one existing reply, in the following manner: > > > > > > - The two new commands are NBD_OPT_PEEK_EXPORT and NBD_OPT_STARTTLS. The > > > former would be used to verify if the server will do TLS for a given > > > export: > > > > > > C: NBD_OPT_PEEK_EXPORT > > > S: NBD_REP_SERVER, with an extra field after the export name > > > containing flags that describe the export (R/O vs R/W state, > > > whether TLS is allowed and/or required). > > IMHO the server should never provide *any* information about the exported > volume(s) until the TLS layer has been fully setup. ie we shouldn't only > think about the actual block data transfers, we should protect the entire > NBD protocol even metadata related operations. This makes sense.

TLS is about the transport, not about a particular NBD export. The only thing that should be communicated is STARTTLS.