On Tue, Nov 18, 2014 at 4:21 PM, Seth Forshee <seth.forshee@xxxxxxxxxxxxx> wrote: >> I asked around a bit, and it turns out there are use cases for nested > containers (i.e. a container within a container) where the rootfs for > the outer container mounts a filesystem containing the rootfs for the > inner container. If that mount is nosuid then suid utilities like ping > aren't going to work in the inner container. > > So since there's a use case for suid in a userns mount and we have what > we belive are sufficient protections against using this as a vector to > get privileges outside the container, I'm planning to move ahead without > the MNT_NOSUID restriction. Any objections? In the general case how'd we prevent suid executable being tricked to do something it shouldn't do by unprivileged mounting into sensitive places (i.e. config files) inside the container? Allowing SUID looks like a slippery slope to me. And there are plenty of solutions to the "ping" problem, AFAICS, that don't involve the suid bit. Disclaimer: I'm pretty ignorant in the field of computer security... Thanks, Miklos -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
