[libvirt] LXC: capset fails with userns

Serge Hallyn serge.hallyn at ubuntu.com
Wed Feb 26 14:54:02 UTC 2014


Quoting Stephan Sachse (ste.sachse at gmail.com):
> for me there is no valid reason why a container is not allowed to set
> file capabilities.

(For the sake of the libvir-list, I replied to this on the lxc-devel@
list with a proposal that should work;  but this particular patch is
not safe, as nothing would stop an unprivileged user from mapping 0
to his uid in a new namespace, adding CAP_SYS_ADMIN, getting back to
the init namespace, and running it with privilege.  Adding a new
capability format which adds the kuid_t of the user_ns root would
solve this.  Thanks Stephan for pushing on this.)

-serge




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