I want to generate SHA512 hashed passwords for inclusion directly into a /etc/shadow file for use with chef's user resource. Normally I'd go to the stdlib's Digest
library for this, but it doesn't generate the hash in the right format:
ruby-1.9.2-p136 :001 > require 'digest/sha2'
=> true
ruby-1.9.2-p136 :002 > Digest::SHA512.hexdigest('test')
=> "ee26b0dd4af7e749aa1a8ee3c10ae9923f618980772e473f8819a5d4940e0db27ac185f8a0e1d5f84f88bc887fd67b143732c304cc5fa9ad8e6f57f50028a8ff"
The format that the shadow file wants is:
$6$/ShPQNXV$HJnibH9lw01qtYqyJQiBf81ggJB2BGUvKA7.kv39HGCeE.gD4C/SS9zAf5BrwOv3VJzvl99FpHYli9E8jykRC0
Things I've looked at:
- The openssl "dgst" module returns the same format as .hexdigest, and its "passwd" module doesn't include SHA512 support.
- String#crypt, but that does not support SHA512. (edit: this is only the case on OSX - modern Linux distros will work if you specify "$6$somesalt" as the salt)
- ruby-crypt gem, but it does not support SHA512
For comparison, something that does return the proper format is PHP's crypt, but I'd rather not have to exec out to PHP for something that should be simple.