On Wed, Nov 19, 2014 at 9:50 AM, Miklos Szeredi <miklos@xxxxxxxxxx> wrote: > 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. ping isn't even suid on my system, it has security.capability xattr instead. Please just get rid of SUID/SGID. It's a legacy, it's a hack, not worth the complexity and potential problems arising from that complexity. 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
