On Wed, Aug 31, 2016 at 01:38:35PM -0700, Andrey Vagin wrote: > On Tue, Aug 30, 2016 at 7:56 PM, Serge E. Hallyn <serge@xxxxxxxxxx> wrote: > > On Fri, Aug 26, 2016 at 04:08:08PM -0700, Andrei Vagin wrote: > >> +struct ns_common *ns_get_owner(struct ns_common *ns) > >> +{ > >> + struct user_namespace *my_user_ns = current_user_ns(); > >> + struct user_namespace *owner, *p; > >> + > >> + /* See if the owner is in the current user namespace */ > >> + owner = p = ns->ops->get_owner(ns); > >> + for (;;) { > >> + if (!p) > >> + return ERR_PTR(-EPERM); > >> + if (p == my_user_ns) > >> + break; > >> + p = p->parent; > >> + } > >> + > >> + return &get_user_ns(owner)->ns; > > > > get_user_ns() bumps the owner's refcount. I don't see where > > this is being dropped, especially when ns_ioctl() uses it in > > the next patch. > > It is dropped in __ns_get_path if a namespace has a dentry, otherwise > it is dropped from nsfs_evict. > > static void *__ns_get_path(struct path *path, struct ns_common *ns) > | return -EPERM; > ... > ns->ops->put(ns); | > got_it: > | /* See if the owner is in the current user namespace > */ > path->mnt = mnt; > | owner = p = ns->ops->get_owner(ns); > path->dentry = dentry; > | for (;;) { > return NULL; > ... > > static void nsfs_evict(struct inode *inode) | > { > | if (!ns_capable(user_ns, CAP_SYS_ADMIN)) > struct ns_common *ns = inode->i_private; > | return -EPERM; > clear_inode(inode); | > ns->ops->put(ns); > | cred = prepare_creds(); > } Gotcha, thanks. -- 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