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 > it earlier and throw in a touch of scaffolding for secid_to_secctx() > we can leave the secid as is for now. This can't be the final solution > as AppArmor will be using the hook someday and we still have the all > modules case to worry about for the next phase. It also assumes that > The BPF module isn't going to suddenly sprout a security context. > Yep this is something that needs to be dealt with, whether it is now or kicked down the road a little further ...
