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Re: Package namespace and Safe init cleanup for plperl [PATCH]

From: Alex Hunsaker <badalex(at)gmail(dot)com>
To: Andrew Dunstan <andrew(at)dunslane(dot)net>
Cc: Tim Bunce <Tim(dot)Bunce(at)pobox(dot)com>, pgsql-hackers(at)postgresql(dot)org, "David E(dot) Wheeler" <david(at)kineticode(dot)com>
Subject: Re: Package namespace and Safe init cleanup for plperl [PATCH]
Date: 2010-02-13 04:08:38
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-hackers
On Fri, Feb 12, 2010 at 17:57, Andrew Dunstan <andrew(at)dunslane(dot)net> wrote:
> Alex Hunsaker wrote:
>>  Yes it could allow people who
>> can set the plperl.*_init functions to muck with the safe.
> It's quite easy to subvert today, sadly. ...

If anything that sounds like an argument for it =)

> But that's quite different from us providing an undocumented way to expose
> arbitrary objects to the Safe container. In that case *we* become
> responsible for any insecure uses, and we don't even have the luxury of
> having put large warnings in the docs, because there aren't any docs.

Hrm... Not sure I agree with this point.  If you are saying there is
some way to subvert safe by using these new vars thats not a bug (or
feature) of upstream safe.  Then I agree.  But if what you are saying
is as a (super)user I muck with these (internal) vars in my on_init
function and things become insecure.  Then I disagree, its just a less
ugly (uniform and perhaps more secure?) way of doing the below:

# hack to make DB::finish_profile available within PL/Perl
use Safe;
my $orig_share_from = \&Safe::share_from;
*Safe::share_from = sub {
        my $obj = shift;
        $obj->$orig_share_from('DB', [ 'finish_profile' ]);
        return $obj->$orig_share_from(@_);

> I still think if we do this at all it needs to be documented and surrounded
> with appropriate warnings.

This is really what I think the issue comes down to.  I think the
feeling is if we document it then we have to support it in the future.
 And we dont have a clear proposal, only a need.  The attitude seems
to be, well its an implementation artifact that might disappear in the
future.  Lets use it to help figure out what that future api should
like like.

I agree with Robert.  At this point in the commit feast its not the
time to be discussing things like this (sorry I could not get to it
sooner Tim!) :(  Though If a patch with good documentation does show
up Ill be happy to review it :)

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Subject: Re: Package namespace and Safe init cleanup for plperl [PATCH]
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