Re: [PATCH 3/4] SUNRPC: Add RPC based upcall mechanism for RPCGSS auth

["J. Bruce Fields" <bfields@fieldses.org>]

On Tue, May 22, 2012 at 06:44:55PM +0400, Stanislav Kinsbursky wrote:
> Yep, we discussed it already.
> The problem is that connect call to unix sockets is done from rpciod
> workqueue because of selinux restrictions.
> IOW UNIX socket path will be traversed staring from rpciod kernel
> thread root. Currently this problem is existent for portmapper
> registration calls - for example LockD, started in container with
> nested root, will be registered in global rpcbind instead of local
> (container's) one.

Thanks for the reminder!

> One of solutions was to export set_fs_root(), but Al Viro doesn't like it.
> 
> So currently I'm thinking about patching network layer - i.e.
> implementing an ability to pass desired path to unix sockets connect
> and bind calls.
> IOW, I'm talking about introducing of "bindat" and "connectat" system calls...

So then we'd resolve the path in the right context and pass down a
(vfsmount, dentry) that rpciod could use in bindat/connectat calls?

> >In particular: the current svcgssd communication method is using one of
> >the sunrpc caches.  If we convert now to this method (which uses a unix
> >socket) would there be a loss in functionality, until the unix sockets
> >problems are fixed?
> >
> 
> I'm afraid, that you are right...
> This new client will connect to root daemon - not containerized one...
> How soon this new unix-socket way will become common practice?
> Maybe I'd be able to patch unix sockets before distro's will use this new version.
> But I don't know, what would be best to do...

Ugh.

Simo, remind me of the reasons for using a unix socket?

--b.