Fix U2FMigrator specs failing with OpenSSL v3.3+

[santiagorodriguez96]

Fixes #463.

Fixed this by using the FIDO U2F Attestation with ES256 Credential test vector provided in WebAuthnAPI specification. I did change the rpIdHash of the assertion from https://exmple.org to https://exmple.org/appid, so we can keep testing for the appid being different than the origin.

This is the script that I used for obtaining the values from the test vector and changing the `rpIdHash`

require "bundler/inline"

gemfile(true) do
  source "https://rubygems.org"

  gem "webauthn"
  gem "base64"
  gem "pry-byebug"
  gem "minitest"
  gem "activesupport"
end

require "webauthn"
require "webauthn/u2f_migrator"
require "base64"
require "pry-byebug"
require "active_support"
require "minitest/autorun"

class BugTest < ActiveSupport::TestCase
  def test_1
    WebAuthn.configuration.allowed_origins = ["https://example.org"]
    app_id = "https://example.org/appid"

    # Data from https://www.w3.org/TR/2025/WD-webauthn-3-20250127/#sctn-test-vectors-fido-u2f-es256
    w3c_u2f_test_vector = {
      registration: {
        attestation_private_key: ['51bd002938fa10b83683ac2a2032d0a7338c7f65a90228cfd1f61b81ec7288d0'].pack('H*'),
        credential_id: ['a4ba6e2d2cfec43648d7d25c5ed5659bc18f2b781538527ebd492de03256bdf4'].pack('H*'),
        client_data_json: ['7b2274797065223a22776562617574686e2e637265617465222c226368616c6c656e6765223a22344851334b5a4335797155486f696666786e73414e344445557955344452715177672d4237583049444159222c226f726967696e223a2268747470733a2f2f6578616d706c652e6f7267222c2263726f73734f726967696e223a66616c73657d'].pack('H*'),
        attestation_object: ['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'].pack('H*'),
      },
      authentication: {
        challenge: ['f90c612981d84f599438de1a500f76926e92cc84bef8e02c6e23553f00485435'].pack('H*'),
        authenticator_data: ['bfabc37432958b063360d3ad6461c9c4735ae7f8edd46592a5e0f01452b2e4b50100000000'].pack('H*'),
        client_data_json: ['7b2274797065223a22776562617574686e2e676574222c226368616c6c656e6765223a222d5178684b59485954316d554f4e3461554139326b6d36537a49532d2d4f417362694e5650774249564455222c226f726967696e223a2268747470733a2f2f6578616d706c652e6f7267222c2263726f73734f726967696e223a66616c73657d'].pack('H*'),
      }
    }

    key_handle = Base64.urlsafe_encode64(w3c_u2f_test_vector[:registration][:credential_id])

    attestation_object = WebAuthn::AttestationObject.deserialize(w3c_u2f_test_vector[:registration][:attestation_object], WebAuthn.configuration.relying_party)

    certificate = Base64.strict_encode64(attestation_object.attestation_statement.attestation_certificate.to_der)

    credential_public_key = WebAuthn::AttestationStatement::FidoU2f::PublicKey.new(
      attestation_object.authenticator_data.attested_credential_data.credential.public_key
    ).to_uncompressed_point
    encoded_credential_public_key = Base64.strict_encode64(credential_public_key)

    migrated_credential =
      WebAuthn::U2fMigrator.new(
        app_id: app_id,
        certificate: certificate,
        key_handle: key_handle,
        public_key: encoded_credential_public_key,
        counter: 41
      )

    original_authenticator_data = WebAuthn::AuthenticatorData.deserialize(w3c_u2f_test_vector[:authentication][:authenticator_data])

    authenticator_data = WebAuthn::FakeAuthenticator::AuthenticatorData.new(
      rp_id_hash: OpenSSL::Digest::SHA256.digest(app_id), # change the original rp_id_hash in order to include the `/appid` path
      credential: original_authenticator_data.attested_credential_data_included? && { id: original_authenticator_data.credential.id, public_key: original_authenticator_data.credential.public_key },
      sign_count: original_authenticator_data.sign_count,
      user_present: original_authenticator_data.user_present?,
      user_verified: original_authenticator_data.user_verified?,
      backup_eligibility: original_authenticator_data.credential_backup_eligible?,
      backup_state: original_authenticator_data.credential_backed_up?,
      aaguid: original_authenticator_data.attested_credential_data_included? && original_authenticator_data.aaguid,
      extensions: original_authenticator_data.extension_data_included? && original_authenticator_data.extension_data,
    ).serialize

    client_data_json = w3c_u2f_test_vector[:authentication][:client_data_json]
    client_data_hash = OpenSSL::Digest::SHA256.digest(client_data_json)

    credential_key_group = OpenSSL::PKey::EC::Group.new(migrated_credential.send(:credential_cose_key).curve.pkey_name)
    credential_public_key_point = OpenSSL::PKey::EC::Point.new(credential_key_group, migrated_credential.send(:credential_cose_key).to_pkey.public_key.to_bn)
    asn1 = OpenSSL::ASN1::Sequence(
      [
        OpenSSL::ASN1::Integer.new(1),
        OpenSSL::ASN1::OctetString(['51bd002938fa10b83683ac2a2032d0a7338c7f65a90228cfd1f61b81ec7288d0'].pack('H*')),
        OpenSSL::ASN1::ObjectId(migrated_credential.send(:credential_cose_key).curve.pkey_name, 0, :EXPLICIT),
        OpenSSL::ASN1::BitString(credential_public_key_point.to_octet_string(:uncompressed), 1, :EXPLICIT),
      ]
    )
    credential_key = OpenSSL::PKey::EC.new(asn1.to_der)

    signature = credential_key.sign('SHA256', authenticator_data + client_data_hash)

    puts "Certificate: #{certificate}"
    puts "Key handle: #{key_handle}"
    puts "Public key: #{encoded_credential_public_key}"
    puts "Assertion challenge: #{Base64.strict_encode64(w3c_u2f_test_vector[:authentication][:challenge])}"
    puts "Client data json: #{Base64.strict_encode64(client_data_json)}"
    puts "Credential public key: #{Base64.strict_encode64(credential_key.to_pem)}"
    puts "Signature: #{Base64.strict_encode64(signature)}"
    puts "Authenticator data: #{Base64.strict_encode64(authenticator_data)}"

    assert WebAuthn::AuthenticatorAssertionResponse.new(
      client_data_json: client_data_json,
      authenticator_data: authenticator_data,
      signature: signature,
    ).valid?(
      w3c_u2f_test_vector[:authentication][:challenge],
      public_key: migrated_credential.credential.public_key,
      sign_count: 0,
      rp_id: app_id
    )
  end

  <<~OUTPUT
    # Running:

    Certificate: 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
    Key handle: pLpuLSz-xDZI19JcXtVlm8GPK3gVOFJ-vUkt4DJWvfQ=
    Public key: BLDWLeazD4bwusepAWlRORwuMYSeLmRmHL0rE819VQitUDsL2io1eppLNEdaKOZbZgtImKnj6bvwgg1DSUKX7dA=
    Assertion challenge: +QxhKYHYT1mUON4aUA92km6SzIS++OAsbiNVPwBIVDU=
    Client data json: eyJ0eXBlIjoid2ViYXV0aG4uZ2V0IiwiY2hhbGxlbmdlIjoiLVF4aEtZSFlUMW1VT040YVVBOTJrbTZTeklTLS1PQXNiaU5WUHdCSVZEVSIsIm9yaWdpbiI6Imh0dHBzOi8vZXhhbXBsZS5vcmciLCJjcm9zc09yaWdpbiI6ZmFsc2V9
    Credential public key: LS0tLS1CRUdJTiBFQyBQUklWQVRFIEtFWS0tLS0tCk1IY0NBUUVFSUZHOUFDazQraEM0Tm9Pc0tpQXkwS2N6akg5bHFRSW96OUgyRzRIc2NvalFvQW9HQ0NxR1NNNDkKQXdFSG9VUURRZ0FFc05ZdDVyTVBodkM2eDZrQmFWRTVIQzR4aEo0dVpHWWN2U3NUelgxVkNLMVFPd3ZhS2pWNgpta3MwUjFvbzVsdG1DMGlZcWVQcHUvQ0NEVU5KUXBmdDBBPT0KLS0tLS1FTkQgRUMgUFJJVkFURSBLRVktLS0tLQo=
    Signature: MEUCID6+MZ0WQ1rW9deqfQbw8LR7/zMvvUnMfAAmgDF2ksUmAiEApgp546w47JGxWS38AC/GznH9fcYUx5Zva62N+1KCg+c=
    Authenticator data: HIcRkL9v+l6dYGTcxfrXQ/usPPfCIO8wnPdFumKDZbcBAAAAAA==
    .

    Finished in 0.002110s, 473.9336 runs/s, 473.9336 assertions/s.

    1 runs, 1 assertions, 0 failures, 0 errors, 0 skips
  OUTPUT
end

[nicolastemciuc]

Thanks! ❤️