On Fri, Mar 06, 2015 at 11:02:43AM -0800, Andy Lutomirski wrote: > On Fri, Mar 6, 2015 at 10:53 AM, Christoph Lameter <c...@linux.com> wrote: > > On Fri, 6 Mar 2015, Serge E. Hallyn wrote: > > > >> Sorry, something about that patch-patch didn't make sense to me, but I > >> need to look more closely. My objection was that you were able to get the > >> pA capabilities into pP without them being in your pI. Your proposed > >> change didn't seem like it would fix that. > > > > Just tried to fix that. Could it be that cap_inherited is never set even > > for a binary that has > > > > christoph@fujitsu-haswell:~$ getcap ambient_test > > > > ambient_test = cap_setpcap,cap_net_admin,cap_net_raw,cap_sys_nice+eip > > I think that's right. fI doesn't set pI.
Right. The idea is that for the running binary to get capability x in its pP, its privileged ancestor must have set x in pI, and the binary itself must be trusted with x in fI. What we are doing is allowing bypassing fI using pA, without bypassing the requirement for x to be in pI. Since pI is intended to be filled (for instance) at login based on username/group, pI generally does not get cleared. At the same time, any software which thinks it is running untrusted code safely without privilege by clearing pI and pP won't be fooled by pA. -serge -- 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/
