Re: Add on_trusted_init and on_untrusted_init to plperl UPDATED [PATCH]

Andrew Dunstan <andrew@dunslane.net> writes:
> %_SHARED has been around for several years now, and if there are genuine 
> security concerns about it ISTM they would apply today, regardless of 
> these patches.

Yes.  I am not at all happy about inserting nonstandard permissions
checks into GUC assign hooks --- they are not really meant for that
and I think there could be unexpected consequences.  Without a serious
demonstration of a real problem that didn't exist before, I'm not in
favor of it.

I think a more reasonable answer is just to add a documentation note
pointing out that %_SHARED should be considered insecure in a multi-user
database.

What I was actually wondering about, however, is the extent to which
the semantics of Perl code could be changed from an on_init hook ---
is there any equivalent of changing search_path or otherwise creating
trojan-horse code that might be executed unexpectedly?  And if so is
there any point in trying to guard against it?  AIUI there isn't
anything that can be done in on_init that couldn't be done in somebody
else's function anyhow.
        regards, tom lane