Adding support for SE-Linux security
in [PgSql]
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From: Greg Smith on 10 Dec 2009 23:54 Tom Lane wrote: > It's been perfectly clear since day one, and was reiterated as recently > as today > http://archives.postgresql.org/message-id/4B21757E.7090806(a)2ndquadrant.com > that what the security community wants is row-level security. I think David Quigley's comments from earlier today summarize the situation better than I did: "For our purposes in DoD we need the MAC Framework and the row based access controls. But if a good starting point is to just do the access control over the database objects, then it will be useful for some commercial cases and some limited military cases" So it's not without value even in its current "Lite" form. But there's clearly a whole lot more use-cases that would benefit from a version with row filtering. -- Greg Smith 2ndQuadrant Baltimore, MD PostgreSQL Training, Services and Support greg(a)2ndQuadrant.com www.2ndQuadrant.com -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
From: Magnus Hagander on 11 Dec 2009 04:31 On Fri, Dec 11, 2009 at 05:45, Tom Lane <tgl(a)sss.pgh.pa.us> wrote: > Robert Haas <robertmhaas(a)gmail.com> writes: >> On Thu, Dec 10, 2009 at 5:08 PM, Tom Lane <tgl(a)sss.pgh.pa.us> wrote: >>> My guess is that a credible SEPostgres offering will require a long-term >>> amount of work at least equal to, and very possibly a good deal more >>> than, what it took to make a native Windows port. > >> The SEPostgres community is surely a lot smaller than the Windows >> community, but I'm not sure whether the effort estimate is accurate or >> not. If "credible" includes "row-level security", then I think I >> might agree, but right now we're just trying to get off the ground. > > It's been perfectly clear since day one, and was reiterated as recently > as today > http://archives.postgresql.org/message-id/4B21757E.7090806(a)2ndquadrant.com > that what the security community wants is row-level security. The If that is true, then shouldn't we have an implementation of row level security *first*, and then an implementation of selinux hooks that work with this row level security feature? Rather than first doing selinux hooks, then row level security, which will likely need new and/or changed hooks... I'm not convinced that row level security is actually that necessary (though it's a nice feature, with or without selinux), but if it is, it seems we are approaching the problem from the wrong direction. -- Magnus Hagander Me: http://www.hagander.net/ Work: http://www.redpill-linpro.com/ -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
From: Stephen Frost on 11 Dec 2009 08:56 Tom, * Tom Lane (tgl(a)sss.pgh.pa.us) wrote: > It's been perfectly clear since day one, and was reiterated as recently > as today > http://archives.postgresql.org/message-id/4B21757E.7090806(a)2ndquadrant.com > that what the security community wants is row-level security. Yes, they do want row-level security. That being said, KaiGai, and others, have pointed out time and time over again that SEPG without row-level security is still useful. Additionally, I see absolutely no way that PG would accept a full SEPG+PGACE+row-level security, etc, patch in as one whole patch, ever. I have extreme doubt it would even be something done over one *release*. That all aside, for the moment, I feel that we should begin a 'two-prong' attack here. First, continue down the path that I've started to lay out for SEPG. Second, let's hash out a design for row-level security using the existing PG security model; ideally using the best features and design decisions of the numerous row-level security systems already implemented by the major SQL vendors today. I'll start a new thread on this specific topic to hopefully pull out anyone who's focus is more on that than on SEPG. > The > proposals to make SEPostgres drive regular SQL permissions never came > out of anyone from that side, they were proposed by PG people looking > for a manageable first step. I do not believe this to be accurate. Josh, were you able to find any public documentation on Trusted Rubix (is that the right name?)? The RDBMS security policy hashed out on the SELinux list during the discussion of Rubix and SEPG certainly included support for table-level objects, did it not? I expect that the SELinux list contributors would have pointed out if they didn't feel that was at all valuable. Perhaps what is at issue is the terminology being used here though, or the approach to enforment being considered. Part of the discussion at the BWPUG meeting involved the option for SEPG to be a "more-restrictive only model" in it's implementation. Essentially, this means that all permissions handling is done the same as it is today, except that once the PG model has decided an action is allowed, SEPG kicks in and does any additional checking of the action being requested it wants and may deny it. At the end of the day, I don't feel that it really changes the architecture of the code though. Perhaps users of SELinux will always want that, but the argument we've heard time and time again here is that this should be a generalized approach that other security managers could hook into and use. To do that, I feel we first have to start with the PG model, which *does* care about all the SQL permissions. Let's extract the various complaints and concerns about SELinux that have been thrown around this list and instead consider our first "client" of the PG modular security framework to be the existing PG SQL permissions system. If we can agree to that, then it's clear that we can't just hand-wave the requirement that it be capable of driving the regular SQL permissions. > Whatever you might believe about the > potential market for SEPostgres, you should divide by about a hundred > as long as it's only an alternate interface to SQL permissions. See > particularly here: > http://wiki.postgresql.org/wiki/SEPostgreSQL_Review_at_the_BWPUG#Revisiting_row-level_security > "Without it, it's questionable whether committing the existing > stripped-down patch really accomplishes anything" --- how much > clearer can they be? Again, let's please address row-level security first at the PG level. That was recommended previously by many on this list and is clearly a useful feature which can stand alone in any case. > If you're not prepared to assume that we're going to do row level > security, it's not apparent why we should be embarking on this course > at all. And if you do assume that, I strongly believe that my effort > estimate above is on the optimistic side. I do assume we're going to do row level security, but I do not feel that we need to particularly put one in front of the other. I also feel that SEPG will be valuable even without row-level security. One of the realms that we discussed at BWPUG for this is PCI compliance. I'm hopeful Josh will have an opportunity to review the PCI compliance "cheat-sheet" that I recall Robert Treat offering and comes to agreement that SEPG w/o row-level security would greatly improve our ability to have a PCI compliant system backed with PG. Thanks, Stephen
From: Robert Haas on 11 Dec 2009 09:20 On Fri, Dec 11, 2009 at 4:31 AM, Magnus Hagander <magnus(a)hagander.net> wrote: > On Fri, Dec 11, 2009 at 05:45, Tom Lane <tgl(a)sss.pgh.pa.us> wrote: >> Robert Haas <robertmhaas(a)gmail.com> writes: >>> On Thu, Dec 10, 2009 at 5:08 PM, Tom Lane <tgl(a)sss.pgh.pa.us> wrote: >>>> My guess is that a credible SEPostgres offering will require a long-term >>>> amount of work at least equal to, and very possibly a good deal more >>>> than, what it took to make a native Windows port. >> >>> The SEPostgres community is surely a lot smaller than the Windows >>> community, but I'm not sure whether the effort estimate is accurate or >>> not. If "credible" includes "row-level security", then I think I >>> might agree, but right now we're just trying to get off the ground. >> >> It's been perfectly clear since day one, and was reiterated as recently >> as today >> http://archives.postgresql.org/message-id/4B21757E.7090806(a)2ndquadrant.com >> that what the security community wants is row-level security. The > > If that is true, then shouldn't we have an implementation of row level > security *first*, and then an implementation of selinux hooks that > work with this row level security feature? Rather than first doing > selinux hooks, then row level security, which will likely need new > and/or changed hooks... > > I'm not convinced that row level security is actually that necessary > (though it's a nice feature, with or without selinux), but if it is, > it seems we are approaching the problem from the wrong direction. I don't think there's a correct ordering to SE-PostgreSQL and row-level security. They're better together, but I don't think either has to be done first. If we were going to pick one to do first, I'd pick SE-PostgreSQL. Row-level security is going to be a @$#! of a project if we want it done right (and we do). ....Robert -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
From: Robert Haas on 11 Dec 2009 09:32
2009/12/11 KaiGai Kohei <kaigai(a)ak.jp.nec.com>: > It tried to provide a set of comprehensive entry points to replace existing > PG checks at once. > However, the SE-PgSQL/Lite patch covers accesses on only database, schema, > tables and columns. Is it necessary to be comprehensive from the beginning? > It might be too aggressive changes at once. > > Frankly, I hesitate to salvage the patch once rejected, as is. > > If we implement a set of security hooks, It seems to me the following approach > is reasonable: > > * It does not touch the existing PG default checks. > The purpose of security hooks are to host "enhanced" security features. > > * It does not deploy hooks on which no security provider is now proposed. > It is important to reduce unnecessary changeset. I think that we should try to move the PG default checks inside the hook functions. If we can't do that cleanly, it's a good sign that the hook functions are not correctly placed to enforce arbitrary security policy. Furthermore, it defeats what I think would be a good side goal here, which is to better modularize the existing code. What I would suggest is that you develop a version of that patch that is stripped down to apply to only a single object type (databases? tables and columns - these might have to be together??) and which addresses Tom's criticisms from the last time around, and post that (on a new thread) for discussion. That will be much easier to review (and I will personally commit to reviewing it) but should allow us to flush out some of the design issues. If we can get agreement on that as a concept patch, we can move on to talking about which object types should be included in a committable version of that patch. ....Robert -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers |