Stanko K.R.
1983014be6
The cookie approach seems like the more secure aproach because it ties the authentication or registration attempt to the user's browser session, but it doesn't work reliably on Chrome for Windows. Also, a simila problem pops up on Chrome for Linux if the session is used instead of a separate cookie. It looks like the browser doesn't propagate the state change through fast enough which results in some requests contaiining the new/updated cookie, and others don't, which results in sporadic failures. Since we use a signed and expiring challange we still get protection from replay attacks and tampering which enables us to omit the cookie entierly and rely on the challange's signature to prove expiration and authenticity. The only thing we lose is the ability to tie and attemp to a single browser session. See: https://github.com/w3c/webauthn/wiki/Explainer:-WebAuthn-challengeURL which proposes to add the same challange fetching logic as part of the standard See: https://github.com/w3c/webauthn/issues/1856 which discusses issues that arise from having expiring challanges (which the spec recommends) See: https://github.com/OneUptime/oneuptime/security/advisories/GHSA-gjjc-pcwp-c74m which is an explot that can happen if the server isn't able to verify the authenticity of challanges that are sent outside of a cookie
68 lines
2.1 KiB
Ruby
68 lines
2.1 KiB
Ruby
# = Action Pack WebAuthn Attestation Response
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#
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# Handles the authenticator response from a WebAuthn registration ceremony.
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# When a user registers a new credential, the authenticator returns an
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# attestation response containing the new public key and credential ID.
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#
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# == Usage
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#
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# response = ActionPack::WebAuthn::Authenticator::AttestationResponse.new(
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# client_data_json: params[:response][:clientDataJSON],
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# attestation_object: params[:response][:attestationObject],
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# origin: "https://example.com"
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# )
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#
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# response.validate!
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#
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# # Store the credential
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# credential_id = response.attestation.credential_id
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# public_key = response.attestation.public_key
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#
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# == Validation
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#
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# In addition to the base Response validations, this class verifies:
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#
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# * The client data type is "webauthn.create"
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# * The attestation format has a registered verifier
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# * The attestation statement passes format-specific verification
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#
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class ActionPack::WebAuthn::Authenticator::AttestationResponse < ActionPack::WebAuthn::Authenticator::Response
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attr_reader :attestation_object
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validate :client_data_type_must_be_create
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validate :attestation_must_be_valid
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def initialize(attestation_object:, **attributes)
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super(**attributes)
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@attestation_object = attestation_object
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end
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# Returns the decoded Attestation object, lazily parsed from the raw
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# attestation object bytes.
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def attestation
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@attestation ||= ActionPack::WebAuthn::Authenticator::Attestation.wrap(attestation_object)
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end
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# Returns the authenticator data extracted from the attestation object.
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def authenticator_data
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attestation.authenticator_data
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end
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private
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def client_data_type_must_be_create
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unless client_data["type"] == "webauthn.create"
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errors.add(:base, "Client data type is not webauthn.create")
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end
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end
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def attestation_must_be_valid
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verifier = ActionPack::WebAuthn.attestation_verifiers[attestation.format]
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if verifier
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verifier.verify!(attestation, client_data_json: client_data_json)
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else
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errors.add(:base, "Unsupported attestation format: #{attestation.format}")
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end
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end
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end
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