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PostgreSQL and the OpenSSL Heartbleed vulnerability

Is your PostgreSQL installation vulnerable to the Heartbleed bug in OpenSSL? The TL;DR; version is "maybe, it depends, you should read this whole thing to find out". If you are vulnerable, it is a high risk vulnerability!

The slightly longer version is that it will be vulnerable if you are using SSL, and not vulnerable if you are not. But the situation is not quite that easy, as you may be using SSL even without planning to. PostgreSQL also not provide any extra protection against the bug - if you are using SSL, you are vulnerable to the bug just as with any other service.

As the bug is in OpenSSL, however, what you need to get patched is your OpenSSL installation and not PostgreSQL itself. And of course, remember to restart your services (this includes both PostgreSQL and any other services using SSL on your system). You will then have to consider in your scenario if you have to replace your SSL keys or not - the same rules apply as to any other service.

It depends on if SSL is enabled

PostgreSQL by default ships with SSL turned off on most platforms. The most notable exception is Debian and derivatives (such as Ubuntu), which enable SSL by default.

If SSL is disabled globally, your installation is not vulnerable.

The easiest way to check this is to just use a simple SQL query:


postgres=# show ssl;
 ssl 
-----
 off
(1 row)

If this parameter returns off, you are not vulnerable. If it returns on, you are.

If you do not need SSL, the easiest fix is to turn this off and restart PostgreSQL. This also brings additional benefits of not paying the overhead of encryption if you don't need it. If you actually use SSL, this is of course not an option.

It depends on your installation

If you have installed PostgreSQL using a package based system, such as yum (from redhat/fedora or from yum.postgresql.org), apt (from debian/ubuntu/etc or from apt.postgresql.org), FreeBSD ports etc, it is up to your operating system to provide a patch. Most major distributions have already done this - you just need to to install it (and restart your services!). If your distribution has not yet updated, you need to convince them to do so ASAP.

If you are using a PostgreSQL installation package that bundles OpenSSL, you need an updated version of this package. The most common example of this is the EnterpriseDB Graphical Installers primarily used on Windows and Mac. We expect a new version of these installers to be released within a day or a few.

Postgres.app is also vulnerable and needs an update, but is normally not used for servers.

The OpenSCG separate download packages are also vulnerable.

For each of these you will have to wait for an updated package to show up in the next couple of days. All package maintainers have been notified, so it's only a matter of time.

Per the www.postgresql.org download pages we do recommend that you always use the "package manager" system for any platform where this is supported, which means most modern Linux or BSD distributions. If you are currently using one of the above installers on these platforms, a quick fix before the packages are out would be to switch to one of the "package manager" platforms that rely on the operating system update process. This may or may not be an option of course, depending on the complexity of the installation.

If you are using a platform where this is not available (such as Windows), your only option is to wait.

pg_hba does not protect you

In PostgreSQL, the SSL negotiation happens before pg_hba.conf is matched. And the vulnerability in OpenSSL is in the negotiation phase. For this reason, even if you have restricted access to your server using pg_hba.conf IP filter rules, or your pg_hba.conf specifies only hostnossl records, this does not protect you.

Obviously, if you have an IP level firewall, either at the host or on the network, that will protect you. But pg_hba does not.

Usage in pgcrypto

The pgcrypto module in PostgreSQL uses OpenSSL to provide encryption functions when available. Since the vulnerability is specifically in the protocol negotiation, use in pgcrypto is not vulnerable to this issue.

Extensions in PostgreSQL 9.1 fixes another pet-peeve

One thing I've really disliked is the fact that contrib modules had installation scripts that enforced the schema to public for the installation. In my opinion, for no useful reason at all.

For example, I often install the pgcrypto contrib module. And I install this in the pgcrypto schema, that I then either add to the search_path variable or just explicitly use in my queries, with things like pcrypto.crypt('foobar','barfoo'). For versions prior to 9.1, being able to do this required me to manually edit the installed pgcrypto.sql file, to remove the SET search_path = public; command.

Extensions in 9.1 makes this so much nicer. To get pgcrypto into it's own schema, I now just need to do:

postgres=# CREATE SCHEMA pgcrypto;
CREATE SCHEMA
postgres=# CREATE EXTENSION pgcrypto SCHEMA pgcrypto;
CREATE EXTENSION

If I happen to create it in public by mistake, I can even move it after the fact!

postgres=# ALTER EXTENSION pgcrypto SET SCHEMA pgcrypto;
ALTER EXTENSION

You still need to create the schema manually - in theory we could auto-create that, but the work is still a lot easier than before. And fully supported!

Integrating django authentication with PostgreSQL

If you've been to any of my pgcrypto talks, you know I'm a fan of exposing a login interface in the database. It's a great way to allow multiple systems to use the same authentication system, without being limited to a single framework. However, it can often be nice and easy to be able to use the account management system in said framework, because it's already there.

When I go to frameworks, django is my current favorite, and I do like the ability to use it's integrated admin system to edit users. For this reason, I wanted to add the ability to use a database function to authenticate other systems using the django user tables. Thanks to the fact that django choose a nicely readable text format for their hashes, and that PostgreSQL has the awesome pgcrypto library, this is pretty simple. Here's a function that will simply return true if authentication was successful, and false if not.


CREATE OR REPLACE FUNCTION django_login (_username text, _password text)
RETURNS boolean
AS $$
BEGIN
   IF EXISTS (SELECT * FROM auth_user WHERE username=_username) THEN
      RETURN encode(pgcrypto.digest(split_part(password, '$', 2) || _password, 'sha1'), 'hex') = 
             split_part(password, '$', 3) FROM auth_user WHERE username=_username;
   ELSE
      RETURN 'f';
   END IF;
END;
$$
LANGUAGE 'plpgsql';

This assumes you have installed pgcrypto in it's own schema, something I always recommend. If you haven't, just remove the schema specifier in the query.

Finally, if you use this type of authentication, remember to use SSL. And don't enable query logging...

pgcon, 1st talk day

We're now up to the third day of pgcon, the first one of the actual conference - the previous ones being dedicated to tutorials. The day started with Selena, me and Dave doing a semi-improvised keynote. Well, it started with Dan saying welcome and going through some details, but he doesn't count... I doubt we actually spread any knowledge with that talk, but at least we got to plug some interesting talks at the conference, and show pictures of elephants.

Missed the start of the Aster talk on Petabyte databases using standard PostgreSQL, but the parts I caught sounded very interesting. I'm especially excited to hear they are planning to contribute a whole set of very interesting features back to core PostgreSQL. This makes a lot of sense since they're building their scaling on standard PostgreSQL and not a heavily modified one like some other players in the area, and it's very nice to see that they are realizing this.

After this talk, it was time for my own talk on PostgreSQL Encryption. I had a hard time deciding the split between pgcrypto and SSL when I made the talk, but I think it came out fairly well. Had a number of very good questions at the end, so clearly some people were interested. Perhaps even Bruce managed to learn something...

After this we had lunch, and I'm now sitting in Greg Smiths talk about benchmarking hardware. This is some very low level stuff compared to what you usually see around database benchmarking, but since this is what sits underneath the database, it's important stuff. And very interesting.

The rest of the day has a lineup of some very nice talks, I think. So there'll be no sitting around in the hallway! And in the evening there is the EnterpriseDB party, of course!

Yesterday had the developer meeting, where a bunch (~20) of the most active developers that are here in Ottawa sat down together for the whole day to discuss topics around the next version of PostgreSQL, and how our development model works. Got some very important discussions started, and actually managed to get agreement on a couple of issues that have previously been going in circles. All in all, a very useful day.

Conferences

I speak at and organize conferences around Open Source in general and PostgreSQL in particular.

Upcoming

Postgres Open 2017
Sep 6-8, 2017
San Francisco, USA
PGConf.EU 2017
Oct 24-27, 2017
Warsaw, Poland
PGConf.Asia
Dec 4-6, 2017
Tokyo, Japan

Past

PGDay.RU
Jul 5-7, 2017
St Petersburg, Russia
PGDay.UK
Jul 4, 2017
London, UK
Amsterdam PUG
Jun 29, 2017
Amsterdam, Netherlands
PGCon 2017
May 23-26, 2017
Ottawa, Canada
FOSS-North
Apr 26, 2017
Gothenburg, Sweden
More past conferences