Re: [libvirt] [PATCH] netns: unix: only allow to find out unix socket in same net namespace

cc libvirt-list On 08/21/2013 01:30 PM, Eric W. Biederman wrote: > Gao feng <gaofeng(a)cn.fujitsu.com&gt; writes: > >> Unix sockets are private resources of net namespace, >> allowing one net namespace to access to other netns's unix >> sockets is meaningless. > > Allowing one net namespace to access another netns's unix socket is > deliberate behavior. This is a desired and useful feature, and > only a misconfiguration of visible files would allow this to be a > problem. > >> I'm researching a problem about shutdown from container, >> if the cotainer shares the same file /run/systemd/private >> with host, when we run shutdown -h xxx in container, the >> shutdown message will be send to the systemd-shutdownd >> through unix socket /run/systemd/private, and because >> systemd-shutdownd is running in host, so finally, the host >> will become shutdown. > > The simple answer is don't do that then. I can see no reason > to share /run outside of the container unless you want this kind of > behavior. > > Quite frankly I want this behavior if I am using network namespaces > to support multiple routing contexts. That is if I am using scripts > like: > > ip netns add other > ip netns exec other script > > I don't want to have to remember to say > ip netns orig exec shutdown -h now > > There are more compelling uses and there is no cost in supporting this > in the kernel. > > What kind of misconfiguration caused someone to complain about this? > libvirt lxc allows user to set up a container which shares the same root directory with host. seems like the unix sockets whose sun_path is an abstract socket address are net namespace aware. Should we use "abstract" type of address instead of a file system pathname for systemd in this case?