Argon2 invalid salt size when specifying a different cost hash

[estebanz01]

Hola de nuevo!

so right now I'm in a bit of a pickle trying to login with a password that is being hashed as argon2 and custom cost hash. I specified it because I need to match the same values used in django for my app written in ruby. I'm getting the following error:

 $ curl -X POST http://localhost:3000/api/v1/login -H 'Content-Type: application/json' -d '{"email": "[email protected]", "password": "holamundo123holamundo"}'
Argon2::ArgonHashFail: Invalid salt size
	/home/esteban/.local/gel/3.2.0/gems/argon2-2.2.0/lib/argon2/ffi_engine.rb:85:in `hash_argon2id_encode'
	/home/esteban/.local/gel/3.2.0/gems/argon2-2.2.0/lib/argon2.rb:34:in `create'
	/home/esteban/.local/gel/ruby/gems/rodauth-2.30.0/lib/rodauth/features/argon2.rb:60:in `password_hash_using_salt'
	/home/esteban/.local/gel/ruby/gems/rodauth-2.30.0/lib/rodauth/features/base.rb:519:in `database_function_password_match?'
	/home/esteban/.local/gel/ruby/gems/rodauth-2.30.0/lib/rodauth/features/base.rb:434:in `password_match?'
	/home/esteban/.local/gel/ruby/gems/rodauth-2.30.0/lib/rodauth/features/login.rb:66:in `block (4 levels) in <module:Rodauth>'
	/home/esteban/.local/gel/ruby/gems/rodauth-2.30.0/lib/rodauth/features/base.rb:606:in `catch'
	/home/esteban/.local/gel/ruby/gems/rodauth-2.30.0/lib/rodauth/features/base.rb:606:in `catch_error'
	/home/esteban/.local/gel/ruby/gems/rodauth-2.30.0/lib/rodauth/features/login.rb:44:in `block (3 levels) in <module:Rodauth>'

Here's the generated hash for a cost hash t_cost: 2, m_cost: 16, p_cost: 8: $argon2id$v=19$m=65536,t=2,p=8$5cUrI7nWSzKldLW7JxYxfw$itpqsB10lQVTLm8qUDOJQI8zhw8JXVbEBIVRXBWZxgY

and for a cost hash t_cost: 2, m_cost: 20, p_cost: 8: $argon2id$v=19$m=1048576,t=2,p=8$ldSO8VFvjdhSrIpaRclRxw$/f47QmzFyYERDSSNwNpwNKOskgFRHghTb1M/DWDEgTk

if I go to the DB and call the salt function, I get the following:

db=# SELECT rodauth_get_salt(3);
       rodauth_get_salt        
-------------------------------
 $argon2id$v=19$m=1048576,t=2,
(1 row)

db=# SELECT rodauth_get_salt(4);
       rodauth_get_salt        
-------------------------------
 $argon2id$v=19$m=65536,t=2,p=
(1 row)

and I can confirm that the user that rodauth is using to connect to the DB has access and can query the rodauth_get_salt method.

I'm really lost on how to debug this, so any guidance will be really appreciated !

Thanks!

# Argon2 rodauth configuration
argon2_secret ENV.fetch('SECRET_VALUE') { SecureRandom.hex(256) }
require_bcrypt? false
# Match cost configuration with default Django
password_hash_cost({ t_cost: 2, m_cost: 16, p_cost: 8 })

[jeremyevans]

Did you pass the :argon2 option when calling Rodauth.create_database_authentication_functions? My guess would be no, considering the returned values are 29 characters, which is what Rodauth returns for bcrypt hashes. See the argon2 feature documentation for how to fix this: https://rodauth.jeremyevans.net/rdoc/files/doc/argon2_rdoc.html . Can you try that and report back whether it works for you?

[jeremyevans]

I tested and had no problems:

# t.ru
require 'roda'
require 'sequel'
DB = Sequel.postgres(:user=>'rodauth_test')

class RodauthTest < Roda
  plugin :common_logger
  plugin :rodauth, json: :only do
    secret = '1'*64
    enable :login, :logout, :create_account, :active_sessions, :json, :jwt, :jwt_refresh, :argon2

    hmac_secret secret
    jwt_secret secret
    require_login_confirmation? false
    require_password_confirmation? false
    login_param 'email'
    # password_hash_cost({ t_cost: 2, m_cost: 20, p_cost: 8 }) # uncomment after creating first user

    argon2_secret 'español'
    require_bcrypt? false
  end

  route do |r|
    r.on 'api/v1' do
      r.rodauth
    end
  end
end

run RodauthTest.app.freeze

With the above configuration, I could create and login to the account with the default cost. After changing the cost, I could login to the already created account that used the default cost, and also create and login to a new account (which took much longer due to the increased cost).

In the future, please provide a tested self contained example like the one above, and tested example code. Your example code provided didn't work with the configuration you provided, and it took a bit a guesswork to determine what configuration would work. Even with the configuration fixed, your curl examples didn't work because the first set create a user for [email protected] and then try to login with [email protected], and the second set try to create the same account used in the first set (which should fail unless you use a different account or wipe the database in between)

I'm not sure why it is failing for you, but it appears to be a local issue.

[estebanz01]

OK, I'll keep debugging. Thanks for the contained example. Re curl commands, probably a copy/paste issue as I posted after a long day of work.

[estebanz01]

I found my issue. The p_cost is not being passed when checking if the password hash matches or not: https://github.com/jeremyevans/rodauth/blob/master/lib/rodauth/features/argon2.rb#L67, I manually changed the regex and the result to be:

/\A\$argon2id\$v=\d+\$m=(\d+),t=(\d+),p=(\d+)/ =~ hash
{ t_cost: $2.to_i, m_cost: Math.log2($1.to_i).to_i, p_cost: $3.to_i }

and the login works as expected. Not sure if this is a bug or the intended behaviour is to ignore p_cost, in any case, I have decided to go with defaults, which are good enough.

hash generated before my change: $argon2id$v=19$m=1048576,t=2,p=1$Cv3Kae1xTcSdrv1xyUajfg$N1KmexbCHR0oHrSOrZoXrU35nnGK6LeknPxnrafGHSU

and the hash generated after my change:
$argon2id$v=19$m=1048576,t=2,p=8$Cv3Kae1xTcSdrv1xyUajfg$4AZWAgwCTysWJ9t99KF1KhDHdhFRusxoZl7WrygtwGA

notice the p_cost as 8.

[jeremyevans]

Rodauth doesn't set the default p_cost, but I'm open to recognizing it and setting it on extraction (in extract_password_hash_cost). Do you want to send in a pull request for that?

[estebanz01]

sure thing