Quoting Eric W. Biederman (ebiederm@xxxxxxxxxxxx): > Stefan Berger <stefanb@xxxxxxxxxxxxxxxxxx> writes: > > > On 07/18/2017 03:01 AM, James Morris wrote: > >> On Thu, 13 Jul 2017, Stefan Berger wrote: > >> > >>> A file shared by 2 containers, one mapping root to uid=1000, the other mapping > >>> root to uid=2000, will show these two xattrs on the host (init_user_ns) once > >>> these containers set xattrs on that file. > >> I may be missing something here, but what happens when say the uid=2000 > >> container and associated user is deleted from the system, then another is > >> created with the same uid? > >> > >> Won't this mean that you have unexpected capabilities turning up in the > >> new container? > >> > > > > Yes, that's right. I don't know any solution for that. We would have to walk the > > filesystems and find all 'stale' xattrs with such a uid. This is independent of > > whether the uid is encoded on the name side, as in this patch, or on the value > > side, as in Serge's original proposal. And uids of a mapped container root user > > don't necessarily have to have an account on the host so that an account > > deletion could trigger that. > > This problem is actually independent of this piece of code entirely. > Any lingering files owned by that uid have the same issue. In particular, any setuid-root files in that container have the precisely analogous issue. -serge _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/containers
