OmniAuth & Facebook: certificate verify failed

Question

I've followed Railscast #235 to try and set up a minimal Facebook authentication.

I've first set up a Twitter authentication, as done by Ryan himself. That worked flawlessly.

I then moved on to adding a Facebook login. However, after authorizing the app the redirect to /auth/facebook/callback fails with:

SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: certificate verify failed

I am working on localhost. I didn't set up any SSL within the app. What am I doing wrong?

Answer 1

The real problem is that Faraday (which Omniauth/Oauth use for their HTTP calls) is not wasn't setting the ca_path variable for OpenSSL. At least on Ubuntu, most root certs are stored in "/etc/ssl/certs". Since Faraday isn't wasn't setting this variable (and currently does not have a method to do so), OpenSSL isn't wasn't finding the root certificate for Facebook's SSL certificate.

I've submitted a pull request to Faraday which will add support for this variable and hopefully they will pull in this change soon. Until then, you can monkeypatch faraday to look like this or use my fork of Faraday. After that, you should specify version 0.3.0 of the OAuth2 gem in your Gemspec which supports the passing of SSL options through to Faraday. All you need to do now is upgrade to Faraday 0.6.1, which supports passing of the ca_path variable and upgrade to OmniAuth 0.2.2, which has the proper dependencies for OAuth2. You'll then be able to properly fix this issue by just adding the following to your Omniauth initializer:

Rails.application.config.middleware.use OmniAuth::Builder do
    provider :facebook, FACEBOOK_KEY, FACEBOOK_SECRET, {:client_options => {:ssl => {:ca_path => "/etc/ssl/certs"}}}
end

So, to recap:

1. Faraday needs to be updated to support SSL ca_path. Install Faraday 0.6.1
2. Your app needs to use OAuth2 version 0.3.0. You may need to fork omniauth since it currently has a minor version dependency in the 0.2.x tree. Upgrade to OmniAuth 0.2.2
3. Modify your provider initializer to point to your system's certificate path ("/etc/ssl/certs" on Ubuntu et al)

Hopefully the next releases of both Faraday and Omniauth will incorporate this solution.

Thanks to KirylP above for setting me on the right path.