Class: Aws::CognitoSrp

Inherits:
Object
  • Object
show all
Defined in:
lib/aws/cognito_srp.rb,
lib/aws/cognito_srp/errors.rb,
lib/aws/cognito_srp/version.rb

Overview

Client for AWS Cognito Identity Provider using Secure Remote Password (SRP).

Borrowed from: gist.github.com/jviney/5fd0fab96cd70d5d46853f052be4744c

This code is a direct translation of the Python version found here: github.com/capless/warrant/blob/ff2e4793d8479e770f2461ef7cbc0c15ee784395/warrant/aws_srp.py

Example usage:

aws_srp = Aws::CognitoSrp.new(
  username: "username",
  password: "password",
  pool_id: "pool-id",
  client_id: "client-id",
  aws_client: Aws::CognitoIdentityProvider::Client.new(region: "us-west-2")
)

aws_srp.authenticate

Defined Under Namespace

Classes: Error, NewPasswordRequired, UnexpectedChallenge, ValueError

Constant Summary collapse

NEW_PASSWORD_REQUIRED = 
"NEW_PASSWORD_REQUIRED"
PASSWORD_VERIFIER = 
"PASSWORD_VERIFIER"
REFRESH_TOKEN = 
"REFRESH_TOKEN"
USER_SRP_AUTH = 
"USER_SRP_AUTH"
N_HEX = 
%w(
  FFFFFFFF FFFFFFFF C90FDAA2 2168C234 C4C6628B 80DC1CD1 29024E08
  8A67CC74 020BBEA6 3B139B22 514A0879 8E3404DD EF9519B3 CD3A431B
  302B0A6D F25F1437 4FE1356D 6D51C245 E485B576 625E7EC6 F44C42E9
  A637ED6B 0BFF5CB6 F406B7ED EE386BFB 5A899FA5 AE9F2411 7C4B1FE6
  49286651 ECE45B3D C2007CB8 A163BF05 98DA4836 1C55D39A 69163FA8
  FD24CF5F 83655D23 DCA3AD96 1C62F356 208552BB 9ED52907 7096966D
  670C354E 4ABC9804 F1746C08 CA18217C 32905E46 2E36CE3B E39E772C
  180E8603 9B2783A2 EC07A28F B5C55DF0 6F4C52C9 DE2BCBF6 95581718
  3995497C EA956AE5 15D22618 98FA0510 15728E5A 8AAAC42D AD33170D
  04507A33 A85521AB DF1CBA64 ECFB8504 58DBEF0A 8AEA7157 5D060C7D
  B3970F85 A6E1E4C7 ABF5AE8C DB0933D7 1E8C94E0 4A25619D CEE3D226
  1AD2EE6B F12FFA06 D98A0864 D8760273 3EC86A64 521F2B18 177B200C
  BBE11757 7A615D6C 770988C0 BAD946E2 08E24FA0 74E5AB31 43DB5BFC
  E0FD108E 4B82D120 A93AD2CA FFFFFFFF FFFFFFFF
).join.freeze
G_HEX = 
'2'
INFO_BITS = 
'Caldera Derived Key'
VERSION = 
"0.4.0"

Instance Method Summary collapse

Constructor Details

#initialize(username:, password:, pool_id:, client_id:, aws_client:) ⇒ CognitoSrp

Returns a new instance of CognitoSrp.



88
89
90
91
92
93
94
95
96
97
98
99
100
 
# File 'lib/aws/cognito_srp.rb', line 88

def initialize(username:, password:, pool_id:, client_id:, aws_client:)
  @username = username
  @password = password
  @pool_id = pool_id
  @client_id = client_id
  @aws_client = aws_client

  @big_n = hex_to_long(N_HEX)
  @g = hex_to_long(G_HEX)
  @k = hex_to_long(hex_hash("00#{N_HEX}0#{G_HEX}"))
  @small_a_value = generate_random_small_a
  @large_a_value = calculate_a
end

Instance Method Details

#authenticate ⇒ Object 



102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
 
# File 'lib/aws/cognito_srp.rb', line 102

def authenticate
  init_auth_response = @aws_client.initiate_auth(
    client_id: @client_id,
    auth_flow: USER_SRP_AUTH,
    auth_parameters: {
      USERNAME: @username,
      SRP_A: long_to_hex(@large_a_value)
    }
  )

  unless init_auth_response.challenge_name == PASSWORD_VERIFIER
    raise UnexpectedChallenge, "Expected Cognito to respond with a #{PASSWORD_VERIFIER} challenge, got #{init_auth_response.challenge_name} instead"
  end

  challenge_response = process_challenge(init_auth_response.challenge_parameters)

  auth_response = @aws_client.respond_to_auth_challenge(
    client_id: @client_id,
    challenge_name: PASSWORD_VERIFIER,
    challenge_responses: challenge_response
  )

  if auth_response.challenge_name == NEW_PASSWORD_REQUIRED
    raise NewPasswordRequired, "Cognito responded to password verifier with a #{NEW_PASSWORD_REQUIRED} challenge"
  end

  auth_response.authentication_result
end

#refresh_tokens(refresh_token) ⇒ Object Also known as: refresh 



131
132
133
134
135
136
137
138
139
140
141
 
# File 'lib/aws/cognito_srp.rb', line 131

def refresh_tokens(refresh_token)
  resp = @aws_client.initiate_auth(
    client_id: @client_id,
    auth_flow: REFRESH_TOKEN,
    auth_parameters: {
      REFRESH_TOKEN: refresh_token
    }
  )

  resp.authentication_result
end