gistfile1.md

I heard from GitHub’s Two-Factor Authentication nearly a couple of days ago when I was reading my RSS feed. I enabled it and couldn’ push to any of my repositories anymore. Learn in this blog post how to fix it.

Two-Factor Authentication

“Is a process involving two stages to verify the identity of an entity trying to access services in a computer or in a network.” GitHub solves this authentication with sending an SMS to a device which wants to push to their platform.

Enabling Two-Factor Authentication

1. Go to your Account Settings.
2. Set up two-factor authentication.
3. You’ll be given the option of setting up 2FA either through a text message, or through an app you can download onto your smart phone.

Once you enter the number on your GitHub page, your account is verified.

Setting Up a Personal Access Token

Since you have enabled 2FA, you can create a personal access token.

1. Open your Account Settings.
2. Click on Applications – this is where you can find the section to create your Personal Access Token.
3. Save the password in some encrypted file.

Testing your Personal Access Token

Run:

$ curl -u <token>:x-oauth-basic https://api.github.com/user

If everythings works well then you should get following JSON output:

{
  "login": "matthias-guenther",
  "id": 264708,
  "avatar_url": "https://avatars.githubusercontent.com/u/264708?",
  "gravatar_id": "9172bb642e29e9959f078f329308faa1",
  "url": "https://api.github.com/users/matthias-guenther",
  "html_url": "https://github.com/matthias-guenther",
  "followers_url": "https://api.github.com/users/matthias-guenther/followers",
  "following_url": "https://api.github.com/users/matthias-guenther/following{/other_user}",
  "gists_url": "https://api.github.com/users/matthias-guenther/gists{/gist_id}",
  "starred_url": "https://api.github.com/users/matthias-guenther/starred{/owner}{/repo}",
  "subscriptions_url": "https://api.github.com/users/matthias-guenther/subscriptions",
  "organizations_url": "https://api.github.com/users/matthias-guenther/orgs",
  "repos_url": "https://api.github.com/users/matthias-guenther/repos",
  "events_url": "https://api.github.com/users/matthias-guenther/events{/privacy}",
  "received_events_url": "https://api.github.com/users/matthias-guenther/received_events",
  "type": "User",
  "site_admin": false,
  "name": "Matthias Günther",
  "company": "",
  "blog": "http://wikimatze.de/about.html",
  "location": "Berlin",
  "email": "matthias@wikimatze.de",
  "hireable": true,
  "bio": "software developer, writer, hiker, jogger, and mobile apps lover",
  "public_repos": 64,
  "public_gists": 11,
  "followers": 54,
  "following": 65,
  "created_at": "2010-05-04T16:46:36Z",
  "updated_at": "2014-03-26T04:43:54Z",
  "private_gists": 0,
  "total_private_repos": 0,
  "owned_private_repos": 0,
  "disk_usage": 57682,
  "collaborators": 0,
  "plan": {
    "name": "free",
    "space": 307200,
    "collaborators": 0,
    "private_repos": 0
  }
}

If something went wrong, you should get a message like:

{
  "message": "Not Found",
  "documentation_url": "http://developer.github.com/v3"
}

Pushing to an HTTPS GitHub URL on Your Own

I had all my repositories checked out via HTTPS. But after enabling 2FA, I couldn’t push to those repositories anymore.

$ git remote -v
  origin https://github.com/matthias-guenther/wikimatze.de.git (fetch)
  origin https://github.com/matthias-guenther/wikimatze.de.git (push)

$ git push origin master
  fatal: 'git@github.com/matthias-guenther/wikimatze.de.git' does not appear to be a git repository
  fatal: Could not read from remote repository.

  Please make sure you have the correct access rights
  and the repository exists.

I tried every combination of passwords, personal access token and even created a new ssh-key, but it didn’t work. I had to change the remote URL to git@github.com:matthias-guenther/wikimatze.de.git to get it running again.

Pushing To An HTTPS GitHub URL On An Organization

I’m the maintainer of vimberlin.de and pushing my changes with the git@* remote URL hack did not work out very well:

$ git remote -v
  origin git@github.com/vimberlin/vimberlin.de.git (fetch)
  origin git@github.com/vimberlin/vimberlin.de.git (push)

$ git push
  fatal: 'git@github.com/vimberlin/vimberlin.de.git' does not appear to be a git repository
  fatal: Could not read from remote repository.

  Please make sure you have the correct access rights
  and the repository exists.

Most posts out there advice to use Keychain in OS X to save your credentials. Since I’m using Xubuntu for developing I had to search after another solution.

Use .netrc File To Store Credentials

The .netrc file contains login and initialization information for managing the auto-login process.

All you have to do is to setup your credentials in ~/.netrc:

machine github.com
login matthias-guenther
password <token>
protocol https

machine gist.github.com
login matthias-guenther
password <token>
protocol https

Where <token> is your personal access token. It would be silly to save your password in plain text.

Encrypt .netrc File with GPG

I assume that you already have your GPG key, you need to run the following command:

$ gpg --encrypt --armor --recipient matthias.guenther@wikimatze.de .netrc

And update the credentials helper:

$ git config --global credential.helper "netrc -f ~/.netrc.asc -v"

Now you should be able to push again.