M. J. Fromberger c57414b83b
Fix padding removal when decrypting a config file. (#36)
OpenSSL uses PKCS#5 padding, and the decryption code was not removing it
correctly. In some cases, this causes the last line of the decrypted config to
be mangled and produces invalid results.

To support this:

- Move config loading to gauth.LoadConfigFile.
- Inject a hook to read the user's password.
- Add unit tests that decryption doesn't corrupt the result.
- Update module dependencies.
- Update Go versions in CI, and fix some config-check warnings.
2020-10-26 18:42:15 -07:00
2014-10-16 22:16:21 -07:00
2018-01-10 00:59:40 -08:00

Build Status

gauth: replace Google Authenticator

Installation

With a Go environment already set up, it should be as easy as go get github.com/pcarrier/gauth.

Eg, with GOPATH=$HOME/go, it will create a binary $HOME/go/bin/gauth.

Usage

  • In web interfaces, pretend you can't read QR codes, get a secret like hret 3ij7 kaj4 2jzg instead.

  • Store one secret per line in ~/.config/gauth.csv, in the format name:secret. For example:

      AWS:   ABCDEFGHIJKLMNOPQRSTUVWXYZ234567ABCDEFGHIJKLMNOPQRSTUVWXYZ234567
      Airbnb:abcd efgh ijkl mnop
      Google:a2b3c4d5e6f7g8h9
      Github:234567qrstuvwxyz
    
  • Restrict access to your user:

      $ chmod 600 ~/.config/gauth.csv
    
  • Run gauth. The progress bar indicates how far the next change is.

      $ gauth
                 prev   curr   next
      AWS        315306 135387 483601
      Airbnb     563728 339206 904549
      Google     453564 477615 356846
      Github     911264 548790 784099
      [=======                      ]
    
  • gauth is convenient to use in watch.

      $ watch -n1 gauth
    
  • Remember to keep your system clock synchronized and to lock your computer when brewing your tea!

Encryption

gauth supports password-based encryption of gauth.csv. To encrypt, use:

    $ openssl enc -aes-128-cbc -md sha256 -in gauth.csv -out ~/.config/gauth.csv
    enter aes-128-cbc encryption password:
    Verifying - enter aes-128-cbc encryption password:

gauth will then prompt you for that password on every run:

    $ gauth
    Encryption password: 
               prev   curr   next
    LastPass   915200 479333 408710

Note that this encryption mechanism is far from ideal from a pure security standpoint. Please read OpenSSL's notes on the subject.

Compatibility

Tested with:

  • Airbnb
  • Apple
  • AWS
  • DreamHost
  • Dropbox
  • Evernote
  • Facebook
  • Gandi
  • Github
  • Google
  • LastPass
  • Linode
  • Microsoft
  • Okta (reported by Bryan Baldwin)
  • WP.com
  • bittrex.com
  • poloniex.com

Please report further results to pierre@gcarrier.fr.

Rooted Android?

If your Android phone is rooted, it's easy to "back up" your secrets from an adb shell into gauth.

# sqlite3 /data/data/com.google.android.apps.authenticator2/databases/database \
          'select email,secret from accounts'

Really, does this make sense?

At least to me, it does. My laptop features encrypted storage, a stronger authentication mechanism, and I take good care of its physical integrity.

My phone also runs arbitrary apps, is constantly connected to the Internet, gets forgotten on tables.

Thanks to the convenience of a command line utility, my usage of 2-factor authentication went from 3 to 10 services over a few days.

Clearly a win for security.

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