How do I make Rails use SSL to connect to PostgreSQL? - ruby-on-rails-3

Question

When I try to connect to the remote PostgreSQL database with a Rails 3.2 project I get this error:
FATAL: no pg_hba.conf entry for host "10.0.0.3", user "projectx", database "projectx", SSL off
My configuration on Rails looks like this:
staging:
adapter: postgresql
database: projectx
username: projectx
password: 123456
host: 10.0.0.3
encoding: utf8
template: template0
min_messages: warning
and on PostgreSQL looks like this:
hostssl all all 0.0.0.0/0 md5
hostssl all all ::/0 md5
Both machines are running on an Ubuntu 12.04.
I found posts saying that it should work automatically, which clearly doesn't happen. I found some saying that libpq didn't have SSL enabled and enabling it solved the problem, but no explanation on how to enable it. I can see when I look at the dependencies of libpq that it depends on the some SSL packages, so I would assume SSL support is compiled.
Some posts recommended adding this:
sslmode: require
or this:
sslmode: enabled
to enable ssl mode, but it had no effect for me. I read that it's silently ignored.
I also tried the database string approach, ending up with:
staging:
adapter: postgresql
database: "host=10.0.0.3 dbname=projectx user=projectx password=123456 sslmode=require"
and then I got the error:
could not connect to server: No such file or directory
Is the server running locally and accepting
connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?
which seems to indicate that Rails was trying to connect to localhost or rather, the local PostgreSQL (there's none) instead of 10.0.0.3.
Any ideas?

Answer 1

As you wrote, normally the Ubuntu 12.x packages are set up so that SSL is activated, works out of the box, and in addition is the first method tried by rails, or any client that lets libpq deal with this stuff, which means almost all clients.
This automatic enabling is not necessarily true with other PostgreSQL packages or with a self-compiled server, so the answers or advice applying to these other contexts don't help with yours.
As your setup should work directly, this answer is a list of things to check to find out what goes wrong. Preferably, use psql first to test a connection setup rather than rails, so that generic postgresql issues can be ruled out first.
Client-side
The client-side sslmode parameter controls the sequence of connect attempts.
To voluntarily avoid SSL, a client would need to put sslmode=disable somewhere in the connection string, or PGSSLMODE=disable in the environment, or mess up with one of the other PGSSL* variables. In the unlikely case your rails process had this in its environment, that would explain the error you're getting, given that pg_hba.conf does not allow non-SSL connections.
Another reason to not try SSL is obviously when libpq is not compiled with SSL support but that's not the case with the Ubuntu packages.
The default for sslmode is prefer, described as:
prefer (default)
first try an SSL connection; if that fails, try a non-SSL connection
The SSL=off at the end of your error message relates to the last connect attempt that fails. It may be that SSL was tried and failed, or not tried at all, we can't know from this message alone. The connect attempt with SSL=off is rejected normally by the server per the policy set in pg_hba.conf (hostssl in the first column).
It's more plausible that the problem is server-side, because there are more things than can go wrong.
Server-side
Here are various things to check server-side:
There should be ssl=on in postgresql.conf (default location: /etc/postgresql/9.1/main/)
when connecting to localhost with psql, you should be greeted with a message like this:
psql (9.1.13)
SSL connection (cipher: DHE-RSA-AES256-SHA, bits: 256)
Type "help" for help.
The ca-certificates package should be installed and up-to-date.
The ssl-cert package should be installed and up-to-date.
Inside the postgres data directory (/var/lib/postgresql/9.1/main by default), there should be soft links:
server.crt -> /etc/ssl/certs/ssl-cert-snakeoil.pem or another valid certificate, and
server.key -> /etc/ssl/private/ssl-cert-snakeoil.key or another valid key.
/etc/ssl/certs and parent directories should be readable and cd'able by postgres.
The postgres unix user should be in the ssl-cert unix group (check with id -a postgres) otherwise it can't read the private key.
If changing postgresql.conf, be sure that postgresql gets restarted before doing any other test.
There shouldn't be any suspicious message about SSL in /var/log/postgresql/postgresql-9.1-main.log at startup time or at the time of the failed connection attempt.

Answer 2

Rails uses the PG gem for postgres to connect see here for the implementation:
https://github.com/rails/rails/blob/02a3c0e771b3e09173412f93d8699d4825a366d6/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb#L881
The PG gem uses libpg (c library) and the documentation on "PG::Connection.new" found here:
http://deveiate.org/code/pg/PGconn.html
Suggests the following options:
host
server hostname
hostaddr
server address (avoids hostname lookup, overrides host)
port
server port number
dbname
connecting database name
user
login user name
password
login password
connect_timeout
maximum time to wait for connection to succeed
options
backend options
tty
(ignored in newer versions of PostgreSQL)
sslmode
(disable|allow|prefer|require)
krbsrvname
kerberos service name
gsslib
GSS library to use for GSSAPI authentication
service
service name to use for additional parameters
So this would indicate that the connection string will not work (since it is not recognised by the adapter, this might be a mysql adapter option)
Also this indicates that the sslmode=required option should work, as this is a basic feature of libpg.
So:
database.yml
staging:
...
sslmode: "require"
...
should definitely do the trick, are you sure you use staging mode? // add sslmode to the other environments too to be sure.
Also libpg uses SSL by default as first try, maybe you see the error with SSL Off because SSL mode failed first, then libpq retried without ssl and eventually raised an error.

Answer 3

Please check your psql version,
older version do not support slmode=require.
It worked for me after upgrading psql to the latest version.