Module: Ibanity::Webhook::Signature

Defined in:
lib/ibanity/webhook.rb

Class Method Summary collapse

Class Method Details

.verify!(payload, signature_header, tolerance) ⇒ Object

Verifies the signature header for a given payload.

Raises an Ibanity::Error in the following cases:

  • the header does not match the expected format

  • the digest does not match the payload

  • the issued at or expiration timestamp is not within the tolerance

  • the audience or issuer does not match the application config

Returns true otherwise



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# File 'lib/ibanity/webhook.rb', line 28

def self.verify!(payload, signature_header, tolerance)
  jwks_loader = ->(options) do
    raise Ibanity::Error.new("The key id from the header didn't match an available signing key", nil) if options[:kid_not_found]

    keys = Ibanity.webhook_keys.select { |key| key.use == "sig" }
                               .map { |key| JWT::JWK.new(key.to_h {|key, value| [key.to_s, value] }) }
    JWT::JWK::Set.new(keys)
  end

  options = {
    aud: Ibanity.client.application_id,
    algorithm: SIGNING_ALGORITHM,
    exp_leeway: tolerance,
    iss: Ibanity.client.base_uri,
    jwks: jwks_loader,
    verify_aud: true,
    verify_iss: true
  }
  jwts = JWT.decode(signature_header, nil, true, options)
  jwt = jwts.first

  validate_digest!(jwt, payload)
  validate_issued_at!(jwt, tolerance)

  true
rescue JWT::ExpiredSignature
  raise_invalid_signature_error!("exp")
rescue JWT::IncorrectAlgorithm
  raise Ibanity::Error.new("Incorrect algorithm for signature", nil)
rescue JWT::InvalidAudError
  raise_invalid_signature_error!("aud")
rescue JWT::InvalidIssuerError
  raise_invalid_signature_error!("iss")
rescue JWT::DecodeError
  raise Ibanity::Error.new("The signature verification failed", nil)
end