On Sun, Sep 17, 2023 at 04:32:04PM +0200, Miklos Szeredi wrote: > On Sun, Sep 17, 2023 at 2:54 AM Matthew House <mattlloydhouse@xxxxxxxxx> wrote: > > > > + list_for_each_entry(r, &m->mnt_mounts, mnt_child) { > > > + if (!capable(CAP_SYS_ADMIN) && > Good point. That issue was nagging at the back of my mind. Having an > explicit flag nicely solves the issue. Ideally we avoid multiple capable(CAP_SYS_ADMIN) calls by only doing it once and saving the return value. capable() call's aren't that cheap. Plus, we should decide whether this should trigger an audit event or not: capable(CAP_SYS_ADMIN) triggers an audit event, ns_capable_noaudit(&init_user_ns, CAP_SYS_ADMIN) wouldn't.