> On Tue, Jul 5, 2011 at 10:49 AM, Alvaro Herrera > <alvhe...@commandprompt.com> wrote: > > Excerpts from Robert Haas's message of mar jul 05 10:19:18 -0400 2011: > > > >> Hmm, OK. I guess what I'm not sure about is - how much should we > >> worry about the fact that this creates several more shared (and > >> therefore nailed?) system catalogs? Anyone have an opinion on that? > > > > "Several"? That would worry me, given that we currently have a small > > number (eight currently). If it's just one more, I don't think it's > > such a big deal. I'm not sure what you mean by nailed though -- I mean, > > for example pg_shdescription is shared but not nailed in the rd_isnailed > > sense of the word, AFAICS. > > Well, right now the patch has pg_shseclabel, and its index, plus a > toast table and a toast index. Not sure why we want/need the toast > table & index there, but the patch has 'em as of now. > As a common belief, TEXT is a variable length data type, so pg_shseclabel need to have its toast table. However, I don't expect the label field get represented as a reference to external pointer, because average length of security context is about 40-60 bytes much less than the threshold to launch toast_save_datum(). Do I need to remove these toast table & index?
> As for whether it needs to be nailed, I'm not sure I understand what > the rules are there. I *think* the rule is that anything that might > need to be consulted before choosing a database must be nailed. If > that's right, we might be able to get by without nailing it, as long > as the label isn't needed during authentication (or its use can be > postponed until after we've connected to a database). > In SELinux, all we are doing in the authentication hook is to acquire security label of the client, without referencing any catalogs. I also plan to support permission checks on the selected database in the future, however, I believe its hook should be placed in CheckMyDatabase() according to the existing checks. Thanks, -- NEC Europe Ltd, SAP Global Competence Center KaiGai Kohei <kohei.kai...@emea.nec.com> -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
