On Tue, Sep 8, 2020 at 8:21 PM John Johansen <john.johansen@xxxxxxxxxxxxx> wrote: > > On 9/8/20 4:37 PM, Casey Schaufler wrote: > > On 9/8/2020 6:35 AM, Stephen Smalley wrote: > >> On Mon, Sep 7, 2020 at 9:28 PM Stephen Smalley > >> <stephen.smalley.work@xxxxxxxxx> wrote: > >>> On Sat, Sep 5, 2020 at 3:07 PM John Johansen > >>> <john.johansen@xxxxxxxxxxxxx> wrote: > >>>> On 9/5/20 11:13 AM, Casey Schaufler wrote: > >>>>> On 9/5/2020 6:25 AM, Paul Moore wrote: > >>>>>> On Fri, Sep 4, 2020 at 7:58 PM Casey Schaufler <casey@xxxxxxxxxxxxxxxx> wrote: > >>>>>>> On 9/4/2020 2:53 PM, Paul Moore wrote: > >>>>>>>> On Fri, Sep 4, 2020 at 5:35 PM Casey Schaufler <casey@xxxxxxxxxxxxxxxx> wrote: > >>>>>>>>> On 9/4/2020 1:08 PM, Paul Moore wrote: > >>>>>> ... > >>>>>> > >>>>>>>> I understand the concerns you mention, they are all valid as far as > >>>>>>>> I'm concerned, but I think we are going to get burned by this code as > >>>>>>>> it currently stands. > >>>>>>> Yes, I can see that. We're getting burned by the non-extensibility > >>>>>>> of secids. It will take someone smarter than me to figure out how to > >>>>>>> fit N secids into 32bits without danger of either failure or memory > >>>>>>> allocation. > >>>>>> Sooo what are the next steps here? It sounds like there is some > >>>>>> agreement that the currently proposed unix_skb_params approach is a > >>>>>> problem, but it also sounds like you just want to merge it anyway? > >>>>> There are real problems with all the approaches. This is by far the > >>>>> least invasive of the lot. If this is acceptable for now I will commit > >>>>> to including the dynamic allocation version in the full stacking > >>>>> (e.g. Smack + SELinux) stage. If it isn't, well, this stage is going > >>>>> to take even longer than it already has. Sigh. > >>>>> > >>>>> > >>>>>> I was sorta hoping for something a bit better. > >>>>> I will be looking at alternatives. I am very much open to suggestions. > >>>>> I'm not even 100% convinced that Stephen's objections to my separate > >>>>> allocation strategy outweigh its advantages. If you have an opinion on > >>>>> that, I'd love to hear it. > >>>>> > >>>> fwiw I prefer the separate allocation strategy, but as you have already > >>>> said it trading off one set of problems for another. I would rather see > >>>> this move forward and one set of trade offs isn't significantly worse > >>>> than the other to me so, either wfm. > >>> I remain unclear that AppArmor needs this patch at all even when > >>> support for SO_PEERSEC lands. > >>> Contrary to the patch description, it is about supporting SCM_SECURITY > >>> for datagram not SO_PEERSEC. And I don't know of any actual users of > >>> SCM_SECURITY even for SELinux, just SO_PEERSEC. > >> I remembered that systemd once tried using SCM_SECURITY but that was a > >> bug since systemd was using it with stream sockets and that wasn't > >> supported by the kernel at the time, > >> https://bugzilla.redhat.com/show_bug.cgi?id=1224211, so systemd > >> switched over to using SO_PEERSEC. Subsequently I did fix > >> SCM_SECURITY to work with stream sockets via kernel commit > >> 37a9a8df8ce9de6ea73349c9ac8bdf6ba4ec4f70 but SO_PEERSEC is still > >> preferred. Looking around, I see that there is still one usage of > >> SCM_SECURITY in systemd-journald but it doesn't seem to be required > >> (if provided, journald will pass the label along but nothing seems to > >> depend on it AFAICT). In any event, I don't believe this patch is > >> needed to support stacking AppArmor. > > > > Stephen is, as is so often the case, correct. AppArmor has a stub > > socket_getpeersec_dgram() that gets removed in patch 23. If I remove > > right but as I said before this is coming, I have been playing with > it and have code. So the series doesn't need it today but sooner than > later it will be needed I don't understand why. Is there a userspace component that relies on SCM_SECURITY today for anything real (more than just blindly passing it along and maybe writing to a log somewhere)? And this doesn't provide support for a composite SCM_SECURITY or SCM_CONTEXT, so it doesn't really solve the stacking problem for it anyway. What am I missing? Why do you care about this patch?
