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|
# frozen_string_literal: true
require "bindata"
require "webauthn/authenticator_data/attested_credential_data"
require "webauthn/error"
module WebAuthn
class AuthenticatorDataFormatError < WebAuthn::Error; end
class AuthenticatorData < BinData::Record
RP_ID_HASH_LENGTH = 32
FLAGS_LENGTH = 1
SIGN_COUNT_LENGTH = 4
endian :big
count_bytes_remaining :data_length
string :rp_id_hash, length: RP_ID_HASH_LENGTH
struct :flags do
bit1 :extension_data_included
bit1 :attested_credential_data_included
bit1 :reserved_for_future_use_4
bit1 :reserved_for_future_use_3
bit1 :reserved_for_future_use_2
bit1 :user_verified
bit1 :reserved_for_future_use_1
bit1 :user_present
end
bit32 :sign_count
count_bytes_remaining :trailing_bytes_length
string :trailing_bytes, length: :trailing_bytes_length
def self.deserialize(data)
read(data)
rescue EOFError
raise AuthenticatorDataFormatError
end
def data
to_binary_s
end
def valid?
(!attested_credential_data_included? || attested_credential_data.valid?) &&
(!extension_data_included? || extension_data) &&
valid_length?
end
def user_flagged?
user_present? || user_verified?
end
def user_present?
flags.user_present == 1
end
def user_verified?
flags.user_verified == 1
end
def attested_credential_data_included?
flags.attested_credential_data_included == 1
end
def extension_data_included?
flags.extension_data_included == 1
end
def credential
if attested_credential_data_included?
attested_credential_data.credential
end
end
def attested_credential_data
@attested_credential_data ||=
AttestedCredentialData.deserialize(trailing_bytes)
rescue AttestedCredentialDataFormatError
raise AuthenticatorDataFormatError
end
def extension_data
@extension_data ||= CBOR.decode(raw_extension_data)
end
def aaguid
raw_aaguid = attested_credential_data.raw_aaguid
unless raw_aaguid == WebAuthn::AuthenticatorData::AttestedCredentialData::ZEROED_AAGUID
attested_credential_data.aaguid
end
end
private
def valid_length?
data_length == base_length + attested_credential_data_length + extension_data_length
end
def raw_extension_data
if extension_data_included?
if attested_credential_data_included?
trailing_bytes[attested_credential_data.length..-1]
else
trailing_bytes.snapshot
end
end
end
def attested_credential_data_length
if attested_credential_data_included?
attested_credential_data.length
else
0
end
end
def extension_data_length
if extension_data_included?
raw_extension_data.length
else
0
end
end
def base_length
RP_ID_HASH_LENGTH + FLAGS_LENGTH + SIGN_COUNT_LENGTH
end
end
end
|
