mirror of
https://github.com/discourse/discourse.git
synced 2024-11-23 08:53:41 +08:00
95 lines
4.7 KiB
Ruby
95 lines
4.7 KiB
Ruby
# frozen_string_literal: true
|
||
require 'cose'
|
||
|
||
module Webauthn
|
||
class SecurityKeyAuthenticationService < SecurityKeyBaseValidationService
|
||
|
||
##
|
||
# See https://w3c.github.io/webauthn/#sctn-verifying-assertion for
|
||
# the steps followed here. Memoized methods are called in their
|
||
# place in the step flow to make the process clearer.
|
||
def authenticate_security_key
|
||
return false if @params.blank? || (!@params.is_a?(Hash) && !@params.is_a?(ActionController::Parameters))
|
||
|
||
# 3. Identify the user being authenticated and verify that this user is the
|
||
# owner of the public key credential source credentialSource identified by credential.id:
|
||
security_key = UserSecurityKey.find_by(credential_id: @params[:credentialId])
|
||
raise(NotFoundError, I18n.t('webauthn.validation.not_found_error')) if security_key.blank?
|
||
raise(OwnershipError, I18n.t('webauthn.validation.ownership_error')) if security_key.user != @current_user
|
||
|
||
# 4. Using credential.id (or credential.rawId, if base64url encoding is inappropriate for your use case),
|
||
# look up the corresponding credential public key and let credentialPublicKey be that credential public key.
|
||
public_key = security_key.public_key
|
||
|
||
# 5. Let cData, authData and sig denote the value of credential’s response's clientDataJSON, authenticatorData, and signature respectively.
|
||
# 6. Let JSONtext be the result of running UTF-8 decode on the value of cData.
|
||
# 7. Let C, the client data claimed as used for the signature, be the result of running an implementation-specific JSON parser on JSONtext.
|
||
client_data
|
||
|
||
# 8. Verify that the value of C.type is the string webauthn.get.
|
||
validate_webauthn_type(::Webauthn::ACCEPTABLE_AUTHENTICATION_TYPE)
|
||
|
||
# 9. Verify that the value of C.challenge equals the base64url encoding of options.challenge.
|
||
validate_challenge
|
||
|
||
# 10. Verify that the value of C.origin matches the Relying Party's origin.
|
||
validate_origin
|
||
|
||
# 11. Verify that the value of C.tokenBinding.status matches the state of Token Binding for the TLS connection
|
||
# over which the attestation was obtained. If Token Binding was used on that TLS connection, also verify
|
||
# that C.tokenBinding.id matches the base64url encoding of the Token Binding ID for the connection.
|
||
# Not using this right now.
|
||
|
||
# 12. Verify that the rpIdHash in authData is the SHA-256 hash of the RP ID expected by the Relying Party.
|
||
validate_rp_id_hash
|
||
|
||
# 13. Verify that the User Present bit of the flags in authData is set.
|
||
# https://blog.bigbinary.com/2011/07/20/ruby-pack-unpack.html
|
||
#
|
||
# bit 0 is the least significant bit - LSB first
|
||
#
|
||
# 14. If user verification is required for this registration, verify that
|
||
# the User Verified bit of the flags in authData is set.
|
||
validate_user_verification
|
||
|
||
# 15. Verify that the values of the client extension outputs in clientExtensionResults and the authenticator
|
||
# extension outputs in the extensions in authData are as expected, considering the client extension input
|
||
# values that were given in options.extensions and any specific policy of the Relying Party regarding
|
||
# unsolicited extensions, i.e., those that were not specified as part of options.extensions. In the
|
||
# general case, the meaning of "are as expected" is specific to the Relying Party and which extensions are in use.
|
||
# Not using this right now.
|
||
|
||
# 16. Let hash be the result of computing a hash over response.clientDataJSON using SHA-256.
|
||
client_data_hash
|
||
|
||
# 17. Using credentialPublicKey, verify that sig is a valid signature over the binary concatenation of authData and hash.
|
||
cose_key = COSE::Key.deserialize(Base64.decode64(security_key.public_key))
|
||
cose_algorithm = COSE::Algorithm.find(cose_key.alg)
|
||
|
||
if cose_algorithm.blank?
|
||
Rails.logger.error("Unknown COSE algorithm encountered. alg: #{cose_key.alg}. user_id: #{@current_user.id}. params: #{@params.inspect}")
|
||
raise(UnknownCOSEAlgorithmError, I18n.t('webauthn.validation.unknown_cose_algorithm_error'))
|
||
end
|
||
|
||
if !cose_key.to_pkey.verify(cose_algorithm.hash_function, signature, auth_data + client_data_hash)
|
||
raise(PublicKeyError, I18n.t('webauthn.validation.public_key_error'))
|
||
end
|
||
|
||
# Success! Update the last used at time for the key.
|
||
security_key.update(last_used: Time.zone.now)
|
||
rescue OpenSSL::PKey::PKeyError
|
||
raise(PublicKeyError, I18n.t('webauthn.validation.public_key_error'))
|
||
end
|
||
|
||
private
|
||
|
||
def auth_data
|
||
@auth_data ||= Base64.decode64(@params[:authenticatorData])
|
||
end
|
||
|
||
def signature
|
||
@signature ||= Base64.decode64(@params[:signature])
|
||
end
|
||
end
|
||
end
|