Quoting Andy Lutomirski (l...@amacapital.net): > On Wed, Feb 4, 2015 at 1:27 PM, Serge E. Hallyn <se...@hallyn.com> wrote: > > Quoting Andy Lutomirski (l...@amacapital.net): > >> On Wed, Feb 4, 2015 at 1:16 PM, Serge E. Hallyn <se...@hallyn.com> wrote: > >> > Quoting Andy Lutomirski (l...@amacapital.net): > >> >> On Wed, Feb 4, 2015 at 10:49 AM, Christoph Lameter <c...@linux.com> > >> >> wrote: > >> >> > + > >> >> > + if (!cap_valid(arg2)) > >> >> > + return -EINVAL; > >> >> > + > >> >> > + new =prepare_creds(); > >> >> > + if (arg3 == 0) > >> >> > + cap_lower(new->cap_ambient, arg2); > >> >> > + else > >> >> > + cap_raise(new->cap_ambient, arg2); > >> >> > + return commit_creds(new); > >> >> > + > >> >> > >> >> This let you add capabilities you don't even have to cap_ambient. I'm > >> >> fine with that as long as the cap evolution rule changes, as above. > >> > > >> > How about if instead we do restrict it to what's in pP? I don't > >> > want CAP_SETPCAP to become a cheap way to get all caps back. With > >> > or without NNP. > >> > >> We'd also have to modify everything that can change pP to change pA as > >> well if we went this route. I'd be okay with that, but it would make > >> the patch much larger, and I'm not entirely sure I see the benefit. > >> It would keep the number of possible states smaller, which could be > >> nice. > > > > Do you mean if we didn't require NNP? I'm suggesting that even if > > we require NNP we should restrict any new bits added to pA to be > > in pP at the prctl call. Then whether or not to drop them from > > pA when they are dropped from pP, I'm not yet certain. > > I mean regardless of whether we require NNP. > > I think that, unless we change the evolution rule, we would need to > drop from pA when bits are dropped from pP to preserve the idea that > dropping bits from pP drops them for good (as long as ruid != 0 or > some securebit is set).
Ok, so iiuc the rules would be: 1. must set nnp and have ns_capable(CAP_SETPCAP) to call prctl(PR_SET_AMBIENT_WHATEVER) 2. adding bits to pA requires they be in pP at prctl time 3. dropping bits from pP drops them also from pA 4. at exec, fP |= pA; pA' = pA Christoph, would these suffice for your use caes? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
