On Fri, Jul 23, 2021 at 06:18:55PM +0200, Kevin Wolf wrote: > Am 23.07.2021 um 12:33 hat Richard W.M. Jones geschrieben: > > Under SELinux, Unix domain sockets have two labels. One is on the > > disk and can be set with commands such as chcon(1). There is a > > different label stored in memory (called the process label). This can > > only be set by the process creating the socket. When using SELinux + > > SVirt and wanting qemu to be able to connect to a qemu-nbd instance, > > you must set both labels correctly first. > > > > For qemu-nbd the options to set the second label are awkward. You can > > create the socket in a wrapper program and then exec into qemu-nbd. > > Or you could try something with LD_PRELOAD. > > > > This commit adds the ability to set the label straightforwardly on the > > command line, via the new --selinux-label flag. (The name of the flag > > is the same as the equivalent nbdkit option.) > > > > A worked example showing how to use the new option can be found in > > this bug: https://bugzilla.redhat.com/show_bug.cgi?id=1984938 > > > > Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1984938 > > Signed-off-by: Richard W.M. Jones <rjo...@redhat.com> > > I suppose this would also be relevant for the built-in NBD server, > especially in the context of qemu-storage-daemon?
It depends on the usage scenario really. nbdkit / qemu-nbd are not commonly run under any SELinux policy, so then end up being unconfined_t. A QEMU NBD client can't connect to an unconfined_t socket, so we need to override it with this arg. In the case of qemu system emulator, under libvirt, it will already have a svirt_t type, so in that case there is no need to override the type for the socket. For qsd there's not really any strong practice established but i expect most current usage is unconfined_t too and would benefit from setting label. > If so, is this something specific to NBD sockets, or would it actually > make sense to have it as a generic option in UnixSocketAddress? It is applicable to inet sockets too in fact. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|