class Net::IMAP::SASL::PlainAuthenticator

Authenticator for the “PLAIN” SASL mechanism, specified in RFC-4616. See Net::IMAP#authenticate.

PLAIN authentication sends the password in cleartext. RFC-3501 encourages servers to disable cleartext authentication until after TLS has been negotiated. RFC-8314 recommends TLS version 1.2 or greater be used for all traffic, and deprecate cleartext access ASAP. PLAIN can be secured by TLS encryption.

Attributes

authcid[R]

Authentication identity: the identity that matches the password.

RFC-2831 uses the term username. “Authentication identity” is the generic term used by RFC-4422. RFC-4616 and many later RFCs abbreviate this to authcid.

authzid[R]

Authorization identity: an identity to act as or on behalf of. The identity form is application protocol specific. If not provided or left blank, the server derives an authorization identity from the authentication identity. The server is responsible for verifying the client’s credentials and verifying that the identity it associates with the client’s authentication identity is allowed to act as (or on behalf of) the authorization identity.

For example, an administrator or superuser might take on another role:

imap.authenticate "PLAIN", "root", passwd, authzid: "user"
password[R]

A password or passphrase that matches the username.

secret[R]

A password or passphrase that matches the username.

username[R]

Authentication identity: the identity that matches the password.

RFC-2831 uses the term username. “Authentication identity” is the generic term used by RFC-4422. RFC-4616 and many later RFCs abbreviate this to authcid.

Public Class Methods

new(username, password, authzid: nil, **) → authenticator click to toggle source
new(username:, password:, authzid: nil, **) → authenticator
new(authcid:, password:, authzid: nil, **) → authenticator

Creates an Authenticator for the “PLAIN” SASL mechanism.

Called by Net::IMAP#authenticate and similar methods on other clients.

Parameters ↑

  • authcid ― Authentication identity that is associated with password.

    username ― An alias for authcid.

  • password ― A password or passphrase associated with the authcid.

  • optional authzid ― Authorization identity to act as or on behalf of.

    When authzid is not set, the server should derive the authorization identity from the authentication identity.

Any other keyword parameters are quietly ignored.

# File lib/net/imap/sasl/plain_authenticator.rb, line 67
def initialize(user = nil, pass = nil,
               authcid: nil, secret: nil,
               username: nil, password: nil, authzid: nil, **)
  username ||= authcid || user or
    raise ArgumentError, "missing username (authcid)"
  password ||= secret || pass or raise ArgumentError, "missing password"
  raise ArgumentError, "username contains NULL" if username.include?(NULL)
  raise ArgumentError, "password contains NULL" if password.include?(NULL)
  raise ArgumentError, "authzid contains NULL"  if authzid&.include?(NULL)
  @username = username
  @password = password
  @authzid  = authzid
  @done = false
end

Public Instance Methods

done? click to toggle source

Returns true when the initial client response was sent.

The authentication should not succeed unless this returns true, but it does not indicate success.

# File lib/net/imap/sasl/plain_authenticator.rb, line 99
def done?; @done end
initial_response? → true click to toggle source

PLAIN can send an initial client response.

# File lib/net/imap/sasl/plain_authenticator.rb, line 86
def initial_response?; true end
process(data) click to toggle source

Responds with the client’s credentials.

# File lib/net/imap/sasl/plain_authenticator.rb, line 89
def process(data)
  return "#@authzid\0#@username\0#@password"
ensure
  @done = true
end