user-based query white list

Looking for a way to limited a user to a specific set of queries.  I don't think 
this can be done right now ... or can it?  Has this feature request surfaced in 
the past?

I currently need this as an extra security measure for a libpq client app (want 
to block arbitrary queries from malicious attackers).  The easiest way I found 
was to add some query_string checks into backend/tcop/postgres.c for the 'Q' and 
'P' commands in PostgresMain().  Seems to work just fine.  If it doesn't match, 
I issue an ereport FATAL since that is seen as a "malicious query execution 
attempt".

I think it is something rather simple to design/implement (probably use a table 
of user allowed queries, support regex matches, etc.. loaded at session startup 
and SIGHUP).

-- 
Andrew Chernow
eSilo, LLC
every bit counts
http://www.esilo.com/