response.rs - webauthn_rp | Philomathic Life

response.rs (106496B)
      1 extern crate alloc;
      2 use crate::{
      3     request::{register::{PublicKeyCredentialUserEntity, UserHandle}, Challenge, RpId, Url},
      4     response::{
      5         auth::error::{
      6             AuthCeremonyErr, AuthenticatorDataErr as AuthAuthDataErr,
      7             AuthenticatorExtensionOutputErr as AuthAuthExtErr,
      8         },
      9         error::{CollectedClientDataErr, CredentialIdErr},
     10         register::error::{AttestationObjectErr, AttestedCredentialDataErr, AuthenticatorDataErr as RegAuthDataErr, AuthenticatorExtensionOutputErr as RegAuthExtErr, PubKeyErr, RegCeremonyErr},
     11     },
     12 };
     13 use alloc::borrow::Cow;
     14 use core::{
     15     borrow::Borrow,
     16     cmp::Ordering,
     17     convert::Infallible,
     18     fmt::{self, Display, Formatter},
     19     hash::{Hash, Hasher},
     20     str,
     21 };
     22 use data_encoding::BASE64URL_NOPAD;
     23 use rsa::sha2::{digest::OutputSizeUser as _, Sha256};
     24 #[cfg(feature = "serde_relaxed")]
     25 use ser_relaxed::SerdeJsonErr;
     26 /// Contains functionality for completing the
     27 /// [authentication ceremony](https://www.w3.org/TR/webauthn-3/#authentication-ceremony).
     28 ///
     29 /// # Examples
     30 ///
     31 /// ```no_run
     32 /// # use core::convert;
     33 /// # use data_encoding::BASE64URL_NOPAD;
     34 /// # use webauthn_rp::{
     35 /// #     hash::hash_set::FixedCapHashSet,
     36 /// #     request::{auth::{error::InvalidTimeout, DiscoverableAuthenticationClientState, DiscoverableCredentialRequestOptions, AuthenticationVerificationOptions}, error::AsciiDomainErr, register::{UserHandle, USER_HANDLE_MAX_LEN, UserHandle64}, AsciiDomain, BackupReq, RpId},
     37 /// #     response::{auth::{error::AuthCeremonyErr, DiscoverableAuthentication64}, error::CollectedClientDataErr, register::{AuthenticatorExtensionOutputStaticState, ClientExtensionsOutputsStaticState, CredentialProtectionPolicy, DynamicState, Ed25519PubKey, CompressedPubKey, StaticState}, AuthenticatorAttachment, Backup, CollectedClientData, CredentialId},
     38 /// #     AuthenticatedCredential, CredentialErr
     39 /// # };
     40 /// # #[derive(Debug)]
     41 /// # enum E {
     42 /// #     CollectedClientData(CollectedClientDataErr),
     43 /// #     RpId(AsciiDomainErr),
     44 /// #     InvalidTimeout(InvalidTimeout),
     45 /// #     SerdeJson(serde_json::Error),
     46 /// #     MissingUserHandle,
     47 /// #     MissingCeremony,
     48 /// #     UnknownCredential,
     49 /// #     Credential(CredentialErr),
     50 /// #     AuthCeremony(AuthCeremonyErr),
     51 /// # }
     52 /// # impl From<AsciiDomainErr> for E {
     53 /// #     fn from(value: AsciiDomainErr) -> Self {
     54 /// #         Self::RpId(value)
     55 /// #     }
     56 /// # }
     57 /// # impl From<CollectedClientDataErr> for E {
     58 /// #     fn from(value: CollectedClientDataErr) -> Self {
     59 /// #         Self::CollectedClientData(value)
     60 /// #     }
     61 /// # }
     62 /// # impl From<InvalidTimeout> for E {
     63 /// #     fn from(value: InvalidTimeout) -> Self {
     64 /// #         Self::InvalidTimeout(value)
     65 /// #     }
     66 /// # }
     67 /// # impl From<serde_json::Error> for E {
     68 /// #     fn from(value: serde_json::Error) -> Self {
     69 /// #         Self::SerdeJson(value)
     70 /// #     }
     71 /// # }
     72 /// # impl From<CredentialErr> for E {
     73 /// #     fn from(value: CredentialErr) -> Self {
     74 /// #         Self::Credential(value)
     75 /// #     }
     76 /// # }
     77 /// # impl From<AuthCeremonyErr> for E {
     78 /// #     fn from(value: AuthCeremonyErr) -> Self {
     79 /// #         Self::AuthCeremony(value)
     80 /// #     }
     81 /// # }
     82 /// let mut ceremonies = FixedCapHashSet::new(128);
     83 /// let rp_id = RpId::Domain(AsciiDomain::try_from("example.com".to_owned())?);
     84 /// let (server, client) = DiscoverableCredentialRequestOptions::passkey(&rp_id).start_ceremony()?;
     85 /// assert!(
     86 ///     ceremonies.insert_remove_all_expired(server).map_or(false, convert::identity)
     87 /// );
     88 /// # #[cfg(feature = "serde")]
     89 /// let authentication = serde_json::from_str::<DiscoverableAuthentication64>(get_authentication_json(client).as_str())?;
     90 /// # #[cfg(feature = "serde")]
     91 /// let user_handle = authentication.response().user_handle();
     92 /// # #[cfg(feature = "serde")]
     93 /// let (static_state, dynamic_state) = get_credential(authentication.raw_id(), &user_handle).ok_or(E::UnknownCredential)?;
     94 /// # #[cfg(all(feature = "custom", feature = "serde"))]
     95 /// let mut cred = AuthenticatedCredential::new(authentication.raw_id(), &user_handle, static_state, dynamic_state)?;
     96 /// # #[cfg(all(feature = "custom", feature = "serde"))]
     97 /// if ceremonies.take(&authentication.challenge()?).ok_or(E::MissingCeremony)?.verify(&rp_id, &authentication, &mut cred, &AuthenticationVerificationOptions::<&str, &str>::default())? {
     98 ///     update_cred(authentication.raw_id(), cred.dynamic_state());
     99 /// }
    100 /// /// Send `DiscoverableAuthenticationClientState` and receive `DiscoverableAuthentication64` JSON from client.
    101 /// # #[cfg(feature = "serde")]
    102 /// fn get_authentication_json(client: DiscoverableAuthenticationClientState<'_, '_, '_>) -> String {
    103 ///     // ⋮
    104 /// #     let client_data_json = BASE64URL_NOPAD.encode(serde_json::json!({
    105 /// #         "type": "webauthn.get",
    106 /// #         "challenge": client.options().public_key.challenge,
    107 /// #         "origin": format!("https://{}", client.options().public_key.rp_id.as_ref()),
    108 /// #         "crossOrigin": false
    109 /// #     }).to_string().as_bytes());
    110 /// #     serde_json::json!({
    111 /// #         "id": "AAAAAAAAAAAAAAAAAAAAAA",
    112 /// #         "rawId": "AAAAAAAAAAAAAAAAAAAAAA",
    113 /// #         "response": {
    114 /// #             "clientDataJSON": client_data_json,
    115 /// #             "authenticatorData": "",
    116 /// #             "signature": "",
    117 /// #             "userHandle": "AA"
    118 /// #         },
    119 /// #         "clientExtensionResults": {},
    120 /// #         "type": "public-key"
    121 /// #     }).to_string()
    122 /// }
    123 /// /// Gets the `AuthenticatedCredential` parts associated with `id` and `user_handle` from the database.
    124 /// fn get_credential(id: CredentialId<&[u8]>, user_handle: &UserHandle64) -> Option<(StaticState<CompressedPubKey<[u8; 32], [u8; 32], [u8; 48], Vec<u8>>>, DynamicState)> {
    125 ///     // ⋮
    126 /// #     Some((StaticState { credential_public_key: CompressedPubKey::Ed25519(Ed25519PubKey::from([0; 32])), extensions: AuthenticatorExtensionOutputStaticState { cred_protect: CredentialProtectionPolicy::UserVerificationRequired, hmac_secret: None, }, client_extension_results: ClientExtensionsOutputsStaticState { prf: None, }, }, DynamicState { user_verified: true, backup: Backup::NotEligible, sign_count: 1, authenticator_attachment: AuthenticatorAttachment::None }))
    127 /// }
    128 /// /// Updates the current `DynamicState` associated with `id` in the database to
    129 /// /// `dyn_state`.
    130 /// fn update_cred(id: CredentialId<&[u8]>, dyn_state: DynamicState) {
    131 ///     // ⋮
    132 /// }
    133 /// # Ok::<_, E>(())
    134 /// ```
    135 pub mod auth;
    136 /// Contains functionality to (de)serialize data to a data store.
    137 #[cfg_attr(docsrs, doc(cfg(feature = "bin")))]
    138 #[cfg(feature = "bin")]
    139 pub mod bin;
    140 /// Contains constants useful for
    141 /// [CTAP2 canonical CBOR encoding form](https://fidoalliance.org/specs/fido-v2.2-rd-20230321/fido-client-to-authenticator-protocol-v2.2-rd-20230321.html#ctap2-canonical-cbor-encoding-form).
    142 mod cbor;
    143 /// Contains functionality that needs to be accessible when `bin` or `serde` are not enabled.
    144 #[cfg_attr(docsrs, doc(cfg(feature = "custom")))]
    145 #[cfg(feature = "custom")]
    146 pub mod custom;
    147 /// Contains error types.
    148 pub mod error;
    149 /// Contains functionality for completing the
    150 /// [registration ceremony](https://www.w3.org/TR/webauthn-3/#registration-ceremony).
    151 ///
    152 /// # Examples
    153 ///
    154 /// ```no_run
    155 /// # use core::convert;
    156 /// # use data_encoding::BASE64URL_NOPAD;
    157 /// # use webauthn_rp::{
    158 /// #     hash::hash_set::FixedCapHashSet,
    159 /// #     request::{register::{error::CreationOptionsErr, CredentialCreationOptions, PublicKeyCredentialUserEntity, RegistrationClientState, UserHandle, UserHandle64, USER_HANDLE_MAX_LEN, RegistrationVerificationOptions}, error::AsciiDomainErr, AsciiDomain, PublicKeyCredentialDescriptor, RpId},
    160 /// #     response::{register::{error::RegCeremonyErr, Registration}, error::CollectedClientDataErr, CollectedClientData},
    161 /// #     RegisteredCredential
    162 /// # };
    163 /// # #[derive(Debug)]
    164 /// # enum E {
    165 /// #     CollectedClientData(CollectedClientDataErr),
    166 /// #     RpId(AsciiDomainErr),
    167 /// #     CreationOptions(CreationOptionsErr),
    168 /// #     SerdeJson(serde_json::Error),
    169 /// #     MissingCeremony,
    170 /// #     RegCeremony(RegCeremonyErr),
    171 /// # }
    172 /// # impl From<AsciiDomainErr> for E {
    173 /// #     fn from(value: AsciiDomainErr) -> Self {
    174 /// #         Self::RpId(value)
    175 /// #     }
    176 /// # }
    177 /// # impl From<CollectedClientDataErr> for E {
    178 /// #     fn from(value: CollectedClientDataErr) -> Self {
    179 /// #         Self::CollectedClientData(value)
    180 /// #     }
    181 /// # }
    182 /// # impl From<CreationOptionsErr> for E {
    183 /// #     fn from(value: CreationOptionsErr) -> Self {
    184 /// #         Self::CreationOptions(value)
    185 /// #     }
    186 /// # }
    187 /// # impl From<serde_json::Error> for E {
    188 /// #     fn from(value: serde_json::Error) -> Self {
    189 /// #         Self::SerdeJson(value)
    190 /// #     }
    191 /// # }
    192 /// # impl From<RegCeremonyErr> for E {
    193 /// #     fn from(value: RegCeremonyErr) -> Self {
    194 /// #         Self::RegCeremony(value)
    195 /// #     }
    196 /// # }
    197 /// # #[cfg(feature = "custom")]
    198 /// let mut ceremonies = FixedCapHashSet::new(128);
    199 /// let rp_id = RpId::Domain(AsciiDomain::try_from("example.com".to_owned())?);
    200 /// # #[cfg(feature = "custom")]
    201 /// let user_handle = get_user_handle();
    202 /// # #[cfg(feature = "custom")]
    203 /// let user = get_user_entity(&user_handle);
    204 /// # #[cfg(feature = "custom")]
    205 /// let creds = get_registered_credentials(user_handle);
    206 /// # #[cfg(feature = "custom")]
    207 /// let (server, client) = CredentialCreationOptions::passkey(&rp_id, user, creds).start_ceremony()?;
    208 /// # #[cfg(feature = "custom")]
    209 /// assert!(
    210 ///     ceremonies.insert_remove_all_expired(server).map_or(false, convert::identity)
    211 /// );
    212 /// # #[cfg(all(feature = "serde_relaxed", feature = "custom"))]
    213 /// let registration = serde_json::from_str::<Registration>(get_registration_json(client).as_str())?;
    214 /// let ver_opts = RegistrationVerificationOptions::<&str, &str>::default();
    215 /// # #[cfg(all(feature = "custom", feature = "serde_relaxed"))]
    216 /// insert_cred(ceremonies.take(&registration.challenge()?).ok_or(E::MissingCeremony)?.verify(&rp_id, &registration, &ver_opts)?);
    217 /// /// Extract `UserHandle` from session cookie if this is not the first credential registered.
    218 /// # #[cfg(feature = "custom")]
    219 /// fn get_user_handle() -> UserHandle64 {
    220 ///     // ⋮
    221 /// #     [0; USER_HANDLE_MAX_LEN].into()
    222 /// }
    223 /// /// Fetch `PublicKeyCredentialUserEntity` info associated with `user`.
    224 /// ///
    225 /// /// If this is the first time a credential is being registered, then `PublicKeyCredentialUserEntity`
    226 /// /// will need to be constructed with `name` and `display_name` passed from the client and `UserHandle::new`
    227 /// /// used for `id`. Once created, this info can be stored such that the entity information
    228 /// /// does not need to be requested for subsequent registrations.
    229 /// # #[cfg(feature = "custom")]
    230 /// fn get_user_entity(user: &UserHandle<USER_HANDLE_MAX_LEN>) -> PublicKeyCredentialUserEntity<'_, '_, '_, USER_HANDLE_MAX_LEN> {
    231 ///     // ⋮
    232 /// #     PublicKeyCredentialUserEntity {
    233 /// #         name: "foo".try_into().unwrap(),
    234 /// #         id: user,
    235 /// #         display_name: None,
    236 /// #     }
    237 /// }
    238 /// /// Send `RegistrationClientState` and receive `Registration` JSON from client.
    239 /// # #[cfg(feature = "serde")]
    240 /// fn get_registration_json(client: RegistrationClientState<'_, '_, '_, '_, '_, '_, USER_HANDLE_MAX_LEN>) -> String {
    241 ///     // ⋮
    242 /// #     let client_data_json = BASE64URL_NOPAD.encode(serde_json::json!({
    243 /// #         "type": "webauthn.create",
    244 /// #         "challenge": client.options().public_key.challenge,
    245 /// #         "origin": format!("https://{}", client.options().public_key.rp_id.as_ref()),
    246 /// #         "crossOrigin": false
    247 /// #     }).to_string().as_bytes());
    248 /// #     serde_json::json!({
    249 /// #         "response": {
    250 /// #             "clientDataJSON": client_data_json,
    251 /// #             "attestationObject": ""
    252 /// #         }
    253 /// #     }).to_string()
    254 /// }
    255 /// /// Fetch the `PublicKeyCredentialDescriptor`s associated with `user`.
    256 /// ///
    257 /// /// This doesn't need to be called when this is the first credential registered for `user`; instead
    258 /// /// an empty `Vec` should be passed.
    259 /// fn get_registered_credentials(
    260 ///     user: UserHandle<USER_HANDLE_MAX_LEN>,
    261 /// ) -> Vec<PublicKeyCredentialDescriptor<Vec<u8>>> {
    262 ///     // ⋮
    263 /// #     Vec::new()
    264 /// }
    265 /// /// Inserts `RegisteredCredential::into_parts` into the database.
    266 /// fn insert_cred(cred: RegisteredCredential<'_, USER_HANDLE_MAX_LEN>) {
    267 ///     // ⋮
    268 /// }
    269 /// # Ok::<_, E>(())
    270 /// ```
    271 pub mod register;
    272 /// Contains functionality to (de)serialize data to/from a client.
    273 #[cfg_attr(docsrs, doc(cfg(feature = "serde")))]
    274 #[cfg(feature = "serde")]
    275 mod ser;
    276 /// Contains functionality to deserialize data from a client in a "relaxed" way.
    277 #[cfg_attr(docsrs, doc(cfg(feature = "serde_relaxed")))]
    278 #[cfg(feature = "serde_relaxed")]
    279 pub mod ser_relaxed;
    280 /// [Backup eligibility](https://www.w3.org/TR/webauthn-3/#backup-eligibility) and
    281 /// [backup state](https://www.w3.org/TR/webauthn-3/#backup-state).
    282 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
    283 pub enum Backup {
    284     /// [BE and BS](https://www.w3.org/TR/webauthn-3/#authdata-flags) flags are `0`.
    285     NotEligible,
    286     /// [BE and BS](https://www.w3.org/TR/webauthn-3/#authdata-flags) flags are `1` and `0` respectively.
    287     Eligible,
    288     /// [BE and BS](https://www.w3.org/TR/webauthn-3/#authdata-flags) flags are `1`.
    289     Exists,
    290 }
    291 impl PartialEq<&Self> for Backup {
    292     #[inline]
    293     fn eq(&self, other: &&Self) -> bool {
    294         *self == **other
    295     }
    296 }
    297 impl PartialEq<Backup> for &Backup {
    298     #[inline]
    299     fn eq(&self, other: &Backup) -> bool {
    300         **self == *other
    301     }
    302 }
    303 /// [`AuthenticatorTransport`](https://www.w3.org/TR/webauthn-3/#enumdef-authenticatortransport).
    304 #[derive(Clone, Copy, Debug)]
    305 pub enum AuthenticatorTransport {
    306     /// [`ble`](https://www.w3.org/TR/webauthn-3/#dom-authenticatortransport-ble).
    307     Ble,
    308     /// [`hybrid`](https://www.w3.org/TR/webauthn-3/#dom-authenticatortransport-hybrid).
    309     Hybrid,
    310     /// [`internal`](https://www.w3.org/TR/webauthn-3/#dom-authenticatortransport-internal).
    311     Internal,
    312     /// [`nfc`](https://www.w3.org/TR/webauthn-3/#dom-authenticatortransport-nfc).
    313     Nfc,
    314     /// [`smart-card`](https://www.w3.org/TR/webauthn-3/#dom-authenticatortransport-smart-card).
    315     SmartCard,
    316     /// [`usb`](https://www.w3.org/TR/webauthn-3/#dom-authenticatortransport-usb).
    317     Usb,
    318 }
    319 impl AuthenticatorTransport {
    320     /// Returns the encoded [`u8`] that `self` represents.
    321     const fn to_u8(self) -> u8 {
    322         match self {
    323             Self::Ble => 0x1,
    324             Self::Hybrid => 0x2,
    325             Self::Internal => 0x4,
    326             Self::Nfc => 0x8,
    327             Self::SmartCard => 0x10,
    328             Self::Usb => 0x20,
    329         }
    330     }
    331 }
    332 /// Set of [`AuthenticatorTransport`]s.
    333 #[derive(Clone, Copy, Debug)]
    334 pub struct AuthTransports(u8);
    335 impl AuthTransports {
    336     /// An empty `AuthTransports`.
    337     #[cfg_attr(docsrs, doc(cfg(feature = "custom")))]
    338     #[cfg(feature = "custom")]
    339     pub const NONE: Self = Self::new();
    340     /// An `AuthTransports` containing all possible [`AuthenticatorTransport`]s.
    341     #[cfg_attr(docsrs, doc(cfg(feature = "custom")))]
    342     #[cfg(feature = "custom")]
    343     pub const ALL: Self = Self::all();
    344     /// Construct an empty `AuthTransports`.
    345     #[cfg(any(feature = "bin", feature = "custom", feature = "serde"))]
    346     pub(super) const fn new() -> Self {
    347         Self(0)
    348     }
    349     #[cfg(any(feature = "bin", feature = "custom"))]
    350     /// Construct an `AuthTransports` containing all `AuthenticatorTransport`s.
    351     const fn all() -> Self {
    352         Self::new()
    353             .add_transport(AuthenticatorTransport::Ble)
    354             .add_transport(AuthenticatorTransport::Hybrid)
    355             .add_transport(AuthenticatorTransport::Internal)
    356             .add_transport(AuthenticatorTransport::Nfc)
    357             .add_transport(AuthenticatorTransport::SmartCard)
    358             .add_transport(AuthenticatorTransport::Usb)
    359     }
    360     /// Returns the number of [`AuthenticatorTransport`]s in `self`.
    361     ///
    362     /// # Examples
    363     ///
    364     /// ```
    365     /// # use webauthn_rp::response::AuthTransports;
    366     /// # #[cfg(feature = "custom")]
    367     /// assert_eq!(AuthTransports::ALL.count(), 6);
    368     /// ```
    369     #[inline]
    370     #[must_use]
    371     pub const fn count(self) -> u32 {
    372         self.0.count_ones()
    373     }
    374     /// Returns `true` iff there are no [`AuthenticatorTransport`]s in `self`.
    375     ///
    376     /// # Examples
    377     ///
    378     /// ```
    379     /// # use webauthn_rp::response::AuthTransports;
    380     /// # #[cfg(feature = "custom")]
    381     /// assert!(AuthTransports::NONE.is_empty());
    382     /// ```
    383     #[inline]
    384     #[must_use]
    385     pub const fn is_empty(self) -> bool {
    386         self.0 == 0
    387     }
    388     /// Returns `true` iff `self` contains `transport`.
    389     ///
    390     /// # Examples
    391     ///
    392     /// ```
    393     /// # use webauthn_rp::response::{AuthTransports, AuthenticatorTransport};
    394     /// # #[cfg(feature = "custom")]
    395     /// assert!(AuthTransports::ALL.contains(AuthenticatorTransport::Ble));
    396     /// ```
    397     #[inline]
    398     #[must_use]
    399     pub const fn contains(self, transport: AuthenticatorTransport) -> bool {
    400         let val = transport.to_u8();
    401         self.0 & val == val
    402     }
    403     /// Returns a copy of `self` with `transport` added.
    404     ///
    405     /// `self` is returned iff `transport` already exists.
    406     #[cfg(any(feature = "bin", feature = "custom", feature = "serde"))]
    407     const fn add_transport(self, transport: AuthenticatorTransport) -> Self {
    408         Self(self.0 | transport.to_u8())
    409     }
    410     /// Returns a copy of `self` with `transport` added.
    411     ///
    412     /// `self` is returned iff `transport` already exists.
    413     ///
    414     /// # Examples
    415     ///
    416     /// ```
    417     /// # use webauthn_rp::response::{AuthTransports, AuthenticatorTransport};
    418     /// assert_eq!(
    419     ///     AuthTransports::NONE
    420     ///         .add(AuthenticatorTransport::Usb)
    421     ///         .count(),
    422     ///     1
    423     /// );
    424     /// assert_eq!(
    425     ///     AuthTransports::ALL.add(AuthenticatorTransport::Usb).count(),
    426     ///     6
    427     /// );
    428     /// ```
    429     #[cfg_attr(docsrs, doc(cfg(feature = "custom")))]
    430     #[cfg(feature = "custom")]
    431     #[inline]
    432     #[must_use]
    433     pub const fn add(self, transport: AuthenticatorTransport) -> Self {
    434         self.add_transport(transport)
    435     }
    436     /// Returns a copy of `self` with `transport` removed.
    437     ///
    438     /// `self` is returned iff `transport` did not exist.
    439     ///
    440     /// # Examples
    441     ///
    442     /// ```
    443     /// # use webauthn_rp::response::{AuthTransports, AuthenticatorTransport};
    444     /// assert_eq!(
    445     ///     AuthTransports::ALL
    446     ///         .remove(AuthenticatorTransport::Internal)
    447     ///         .count(),
    448     ///     5
    449     /// );
    450     /// assert_eq!(
    451     ///     AuthTransports::NONE.remove(AuthenticatorTransport::Usb).count(),
    452     ///     0
    453     /// );
    454     /// ```
    455     #[cfg_attr(docsrs, doc(cfg(feature = "custom")))]
    456     #[cfg(feature = "custom")]
    457     #[inline]
    458     #[must_use]
    459     pub const fn remove(self, transport: AuthenticatorTransport) -> Self {
    460         Self(self.0 & !transport.to_u8())
    461     }
    462 }
    463 /// [`AuthenticatorAttachment`](https://www.w3.org/TR/webauthn-3/#enumdef-authenticatorattachment).
    464 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
    465 pub enum AuthenticatorAttachment {
    466     /// No attachment information.
    467     None,
    468     /// [`platform`](https://www.w3.org/TR/webauthn-3/#dom-authenticatorattachment-platform).
    469     Platform,
    470     /// [`cross-platform`](https://www.w3.org/TR/webauthn-3/#dom-authenticatorattachment-cross-platform).
    471     CrossPlatform,
    472 }
    473 impl PartialEq<&Self> for AuthenticatorAttachment {
    474     #[inline]
    475     fn eq(&self, other: &&Self) -> bool {
    476         *self == **other
    477     }
    478 }
    479 impl PartialEq<AuthenticatorAttachment> for &AuthenticatorAttachment {
    480     #[inline]
    481     fn eq(&self, other: &AuthenticatorAttachment) -> bool {
    482         **self == *other
    483     }
    484 }
    485 /// The maximum number of bytes that can make up a Credential ID
    486 /// [per WebAuthn](https://www.w3.org/TR/webauthn-3/#credential-id).
    487 pub const CRED_ID_MAX_LEN: usize = 1023;
    488 /// The minimum number of bytes that can make up a Credential ID
    489 /// [per WebAuthn](https://www.w3.org/TR/webauthn-3/#credential-id).
    490 ///
    491 /// The spec does not call out this value directly instead it states the following:
    492 ///
    493 /// > Credential IDs are generated by authenticators in two forms:
    494 /// >
    495 /// > * At least 16 bytes that include at least 100 bits of entropy, or
    496 /// > * The [public key credential source](https://www.w3.org/TR/webauthn-3/#public-key-credential-source),
    497 /// >   without its Credential ID or mutable items, encrypted so only its managing
    498 /// >   authenticator can decrypt it. This form allows the authenticator to be nearly
    499 /// >   stateless, by having the Relying Party store any necessary state.
    500 ///
    501 /// One of the immutable items of the public key credential source is the private key
    502 /// which for any real-world signature algorithm will always be at least 16 bytes.
    503 pub const CRED_ID_MIN_LEN: usize = 16;
    504 /// A [Credential ID](https://www.w3.org/TR/webauthn-3/#credential-id) that is made up of
    505 /// [`CRED_ID_MIN_LEN`]–[`CRED_ID_MAX_LEN`] bytes.
    506 #[derive(Clone, Copy, Debug)]
    507 pub struct CredentialId<T>(T);
    508 impl<T> CredentialId<T> {
    509     /// Returns the contained data consuming `self`.
    510     #[inline]
    511     pub fn into_inner(self) -> T {
    512         self.0
    513     }
    514     /// Returns the contained data.
    515     #[inline]
    516     pub const fn inner(&self) -> &T {
    517         &self.0
    518     }
    519 }
    520 impl<'a> CredentialId<&'a [u8]> {
    521     /// Creates a `CredentialId` from a `slice`.
    522     #[expect(single_use_lifetimes, reason = "false positive")]
    523     fn from_slice<'b: 'a>(value: &'b [u8]) -> Result<Self, CredentialIdErr> {
    524         if (CRED_ID_MIN_LEN..=CRED_ID_MAX_LEN).contains(&value.len()) {
    525             Ok(Self(value))
    526         } else {
    527             Err(CredentialIdErr)
    528         }
    529     }
    530 }
    531 impl<T: AsRef<[u8]>> AsRef<[u8]> for CredentialId<T> {
    532     #[inline]
    533     fn as_ref(&self) -> &[u8] {
    534         self.0.as_ref()
    535     }
    536 }
    537 impl<T: Borrow<[u8]>> Borrow<[u8]> for CredentialId<T> {
    538     #[inline]
    539     fn borrow(&self) -> &[u8] {
    540         self.0.borrow()
    541     }
    542 }
    543 impl<'a: 'b, 'b> From<&'a CredentialId<Vec<u8>>> for CredentialId<&'b Vec<u8>> {
    544     #[inline]
    545     fn from(value: &'a CredentialId<Vec<u8>>) -> Self {
    546         Self(&value.0)
    547     }
    548 }
    549 impl<'a: 'b, 'b> From<CredentialId<&'a Vec<u8>>> for CredentialId<&'b [u8]> {
    550     #[inline]
    551     fn from(value: CredentialId<&'a Vec<u8>>) -> Self {
    552         Self(value.0.as_slice())
    553     }
    554 }
    555 impl<'a: 'b, 'b> From<&'a CredentialId<Vec<u8>>> for CredentialId<&'b [u8]> {
    556     #[inline]
    557     fn from(value: &'a CredentialId<Vec<u8>>) -> Self {
    558         Self(value.0.as_slice())
    559     }
    560 }
    561 impl From<CredentialId<&[u8]>> for CredentialId<Vec<u8>> {
    562     #[inline]
    563     fn from(value: CredentialId<&[u8]>) -> Self {
    564         Self(value.0.to_owned())
    565     }
    566 }
    567 impl<T: PartialEq<T2>, T2: PartialEq<T>> PartialEq<CredentialId<T>> for CredentialId<T2> {
    568     #[inline]
    569     fn eq(&self, other: &CredentialId<T>) -> bool {
    570         self.0 == other.0
    571     }
    572 }
    573 impl<T: PartialEq<T2>, T2: PartialEq<T>> PartialEq<CredentialId<T>> for &CredentialId<T2> {
    574     #[inline]
    575     fn eq(&self, other: &CredentialId<T>) -> bool {
    576         **self == *other
    577     }
    578 }
    579 impl<T: PartialEq<T2>, T2: PartialEq<T>> PartialEq<&CredentialId<T>> for CredentialId<T2> {
    580     #[inline]
    581     fn eq(&self, other: &&CredentialId<T>) -> bool {
    582         *self == **other
    583     }
    584 }
    585 impl<T: Eq> Eq for CredentialId<T> {}
    586 impl<T: Hash> Hash for CredentialId<T> {
    587     #[inline]
    588     fn hash<H: Hasher>(&self, state: &mut H) {
    589         self.0.hash(state);
    590     }
    591 }
    592 impl<T: PartialOrd<T2>, T2: PartialOrd<T>> PartialOrd<CredentialId<T>> for CredentialId<T2> {
    593     #[inline]
    594     fn partial_cmp(&self, other: &CredentialId<T>) -> Option<Ordering> {
    595         self.0.partial_cmp(&other.0)
    596     }
    597 }
    598 impl<T: Ord> Ord for CredentialId<T> {
    599     #[inline]
    600     fn cmp(&self, other: &Self) -> Ordering {
    601         self.0.cmp(&other.0)
    602     }
    603 }
    604 // We define a separate type to ensure challenges sent to the client are always randomly generated;
    605 // otherwise one could deserialize arbitrary data into a `Challenge`.
    606 /// Copy of [`Challenge`] sent back from the client.
    607 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
    608 pub struct SentChallenge(pub u128);
    609 impl PartialEq<&Self> for SentChallenge {
    610     #[inline]
    611     fn eq(&self, other: &&Self) -> bool {
    612         *self == **other
    613     }
    614 }
    615 impl PartialEq<SentChallenge> for &SentChallenge {
    616     #[inline]
    617     fn eq(&self, other: &SentChallenge) -> bool {
    618         **self == *other
    619     }
    620 }
    621 impl PartialOrd for SentChallenge {
    622     #[inline]
    623     fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
    624         Some(self.cmp(other))
    625     }
    626 }
    627 impl Ord for SentChallenge {
    628     #[inline]
    629     fn cmp(&self, other: &Self) -> Ordering {
    630         self.0.cmp(&other.0)
    631     }
    632 }
    633 impl Hash for SentChallenge {
    634     #[inline]
    635     fn hash<H: Hasher>(&self, state: &mut H) {
    636         state.write_u128(self.0);
    637     }
    638 }
    639 /// An [`origin`](https://www.w3.org/TR/webauthn-3/#dom-collectedclientdata-origin) or
    640 /// [`topOrigin`](https://www.w3.org/TR/webauthn-3/#dom-collectedclientdata-toporigin).
    641 #[derive(Debug, Eq)]
    642 pub struct Origin<'a>(pub Cow<'a, str>);
    643 impl PartialEq<Origin<'_>> for Origin<'_> {
    644     #[inline]
    645     fn eq(&self, other: &Origin<'_>) -> bool {
    646         self.0 == other.0
    647     }
    648 }
    649 impl PartialEq<&Origin<'_>> for Origin<'_> {
    650     #[inline]
    651     fn eq(&self, other: &&Origin<'_>) -> bool {
    652         *self == **other
    653     }
    654 }
    655 impl PartialEq<Origin<'_>> for &Origin<'_> {
    656     #[inline]
    657     fn eq(&self, other: &Origin<'_>) -> bool {
    658         **self == *other
    659     }
    660 }
    661 impl PartialEq<str> for Origin<'_> {
    662     #[inline]
    663     fn eq(&self, other: &str) -> bool {
    664         self.0.as_ref() == other
    665     }
    666 }
    667 impl PartialEq<Origin<'_>> for str {
    668     #[inline]
    669     fn eq(&self, other: &Origin<'_>) -> bool {
    670         *other == *self
    671     }
    672 }
    673 impl PartialEq<&str> for Origin<'_> {
    674     #[inline]
    675     fn eq(&self, other: &&str) -> bool {
    676         *self == **other
    677     }
    678 }
    679 impl PartialEq<Origin<'_>> for &str {
    680     #[inline]
    681     fn eq(&self, other: &Origin<'_>) -> bool {
    682         **self == *other
    683     }
    684 }
    685 impl PartialEq<String> for Origin<'_> {
    686     #[inline]
    687     fn eq(&self, other: &String) -> bool {
    688         self.0 == *other
    689     }
    690 }
    691 impl PartialEq<Origin<'_>> for String {
    692     #[inline]
    693     fn eq(&self, other: &Origin<'_>) -> bool {
    694         *other == *self
    695     }
    696 }
    697 impl PartialEq<Url> for Origin<'_> {
    698     #[inline]
    699     fn eq(&self, other: &Url) -> bool {
    700         self.0.as_ref() == other.as_ref()
    701     }
    702 }
    703 impl PartialEq<Origin<'_>> for Url {
    704     #[inline]
    705     fn eq(&self, other: &Origin<'_>) -> bool {
    706         *other == *self
    707     }
    708 }
    709 impl PartialEq<&Url> for Origin<'_> {
    710     #[inline]
    711     fn eq(&self, other: &&Url) -> bool {
    712         *self == **other
    713     }
    714 }
    715 impl PartialEq<Origin<'_>> for &Url {
    716     #[inline]
    717     fn eq(&self, other: &Origin<'_>) -> bool {
    718         **self == *other
    719     }
    720 }
    721 /// [Authenticator data flags](https://www.w3.org/TR/webauthn-3/#authdata-flags).
    722 #[derive(Clone, Copy, Debug)]
    723 pub struct Flag {
    724     /// [`UP` flag](https://www.w3.org/TR/webauthn-3/#authdata-flags-up).
    725     ///
    726     /// Note this is always `true` when part of [`auth::AuthenticatorData::flags`].
    727     pub user_present: bool,
    728     /// [`UV` flag](https://www.w3.org/TR/webauthn-3/#concept-user-verified).
    729     pub user_verified: bool,
    730     /// [`BE`](https://www.w3.org/TR/webauthn-3/#backup-eligibility) and
    731     /// [`BS`](https://www.w3.org/TR/webauthn-3/#backup-state) flags.
    732     pub backup: Backup,
    733 }
    734 /// [Authenticator data](https://www.w3.org/TR/webauthn-3/#authenticator-data).
    735 pub(super) trait AuthData<'a>: Sized {
    736     /// Error returned by [`Self::user_is_not_present`].
    737     ///
    738     /// This should be [`Infallible`] in the event user must not always be present.
    739     type UpBitErr;
    740     /// [`attestedCredentialData`](https://www.w3.org/TR/webauthn-3/#authdata-attestedcredentialdata).
    741     type CredData;
    742     /// [`extensions`](https://www.w3.org/TR/webauthn-3/#authdata-extensions).
    743     type Ext: AuthExtOutput + Copy;
    744     /// Errors iff the user must always be present.
    745     fn user_is_not_present() -> Result<(), Self::UpBitErr>;
    746     /// `true` iff `AT` bit (i.e., bit 6) in [`Self::flag_data`] can and must be set to 1.
    747     fn contains_at_bit() -> bool;
    748     /// Constructor.
    749     fn new(rp_id_hash: &'a [u8], flags: Flag, sign_count: u32, attested_credential_data: Self::CredData, extensions: Self::Ext) -> Self;
    750     /// [`rpIdHash`](https://www.w3.org/TR/webauthn-3/#authdata-rpidhash).
    751     fn rp_hash(&self) -> &'a [u8];
    752     /// [`flags`](https://www.w3.org/TR/webauthn-3/#authdata-flags).
    753     fn flag(&self) -> Flag;
    754 }
    755 /// [`CollectedClientData`](https://www.w3.org/TR/webauthn-3/#dictdef-collectedclientdata).
    756 #[derive(Debug)]
    757 pub struct CollectedClientData<'a> {
    758     /// [`challenge`](https://www.w3.org/TR/webauthn-3/#dom-collectedclientdata-challenge).
    759     pub challenge: SentChallenge,
    760     /// [`origin`](https://www.w3.org/TR/webauthn-3/#dom-collectedclientdata-origin).
    761     pub origin: Origin<'a>,
    762     /// [`crossOrigin`](https://www.w3.org/TR/webauthn-3/#dom-collectedclientdata-crossorigin).
    763     pub cross_origin: bool,
    764     /// [`topOrigin`](https://www.w3.org/TR/webauthn-3/#dom-collectedclientdata-toporigin).
    765     ///
    766     /// When `CollectedClientData` is constructed via [`Self::from_client_data_json`], this can only be
    767     /// `Some` if [`Self::cross_origin`]; and if `Some`, it will be different than [`Self::origin`].
    768     pub top_origin: Option<Origin<'a>>,
    769 }
    770 impl<'a> CollectedClientData<'a> {
    771     /// Parses `json` based on the
    772     /// [limited verification algorithm](https://www.w3.org/TR/webauthn-3/#clientdatajson-verification).
    773     ///
    774     /// Additionally, [`topOrigin`](https://www.w3.org/TR/webauthn-3/#dom-collectedclientdata-toporigin) is only
    775     /// allowed to exist if it has a different value than
    776     /// [`origin`](https://www.w3.org/TR/webauthn-3/#dom-collectedclientdata-origin) and
    777     /// [`crossOrigin`](https://www.w3.org/TR/webauthn-3/#dom-collectedclientdata-crossorigin) is `true`.
    778     ///
    779     /// `REGISTRATION` iff [`type`](https://www.w3.org/TR/webauthn-3/#dom-collectedclientdata-type) must be
    780     /// `"webauthn.create"`; otherwise it must be `"webauthn.get"`.
    781     ///
    782     /// # Errors
    783     ///
    784     /// Errors iff `json` cannot be parsed based on the aforementioned requirements.
    785     ///
    786     /// # Examples
    787     ///
    788     /// ```
    789     /// # use webauthn_rp::response::{error::CollectedClientDataErr, CollectedClientData};
    790     /// assert!(!CollectedClientData::from_client_data_json::<true>(br#"{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":false}"#.as_slice())?.cross_origin);
    791     /// assert!(!CollectedClientData::from_client_data_json::<false>(br#"{"type":"webauthn.get","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":false}"#.as_slice())?.cross_origin);
    792     /// # Ok::<_, CollectedClientDataErr>(())
    793     /// ```
    794     #[expect(single_use_lifetimes, reason = "false positive")]
    795     #[inline]
    796     pub fn from_client_data_json<'b: 'a, const REGISTRATION: bool>(json: &'b [u8]) -> Result<Self, CollectedClientDataErr> {
    797         LimitedVerificationParser::<REGISTRATION>::parse(json)
    798     }
    799     /// Parses `json` in a "relaxed" way.
    800     ///
    801     /// Unlike [`Self::from_client_data_json`] which requires `json` to be an output from the
    802     /// [JSON-compatible serialization of client data](https://www.w3.org/TR/webauthn-3/#clientdatajson-serialization),
    803     /// this parses `json` based entirely on the
    804     /// [`CollectedClientData`](https://www.w3.org/TR/webauthn-3/#dictdef-collectedclientdata) Web IDL `dictionary`.
    805     ///
    806     /// L1 clients predate the JSON-compatible serialization of client data; additionally there are L2 and L3
    807     /// clients that don't adhere to the JSON-compatible serialization of client data despite being required to.
    808     /// These clients serialize `CollectedClientData` so that it's valid JSON and conforms to the Web IDL `dictionary`
    809     /// and nothing more. Furthermore, when not relying on the
    810     /// [limited verification algorithm](https://www.w3.org/TR/webauthn-3/#clientdatajson-verification), the spec
    811     /// requires the data to be decoded in a way equivalent to
    812     /// [UTF-8 decode](https://encoding.spec.whatwg.org/#utf-8-decode) which both interprets a leading zero
    813     /// width no-breaking space (i.e., U+FEFF) as a byte-order mark (BOM) as well as replaces any sequences of
    814     /// invalid UTF-8 code units with the replacement character (i.e., U+FFFD). That is precisely what this
    815     /// function does.
    816     ///
    817     /// # Errors
    818     ///
    819     /// Errors iff any of the following is true:
    820     /// * The payload is not valid JSON _after_ ignoring a leading U+FEFF and replacing any sequences of invalid
    821     ///   UTF-8 code units with U+FFFD.
    822     /// * The JSON does not conform to the Web IDL `dictionary`.
    823     /// * [`type`](https://www.w3.org/TR/webauthn-3/#dom-collectedclientdata-type) is not `"webauthn.create"`
    824     ///   or `"webauthn.get"` when `REGISTRATION` and `!REGISTRATION` respectively.
    825     /// * [`challenge`](https://www.w3.org/TR/webauthn-3/#dom-collectedclientdata-challenge) is not a
    826     ///   base64url-encoded [`Challenge`].
    827     /// * Existence of duplicate keys for the keys that are expected.
    828     ///
    829     /// # Examples
    830     ///
    831     /// ```
    832     /// # use webauthn_rp::response::{ser_relaxed::SerdeJsonErr, CollectedClientData};
    833     /// assert!(!CollectedClientData::from_client_data_json_relaxed::<true>(b"\xef\xbb\xbf{
    834     ///   \"type\": \"webauthn.create\",
    835     ///   \"origin\": \"https://example.com\",
    836     ///   \"f\xffo\": 123,
    837     ///   \"topOrigin\": \"https://example.com\",
    838     ///   \"challenge\": \"AAAAAAAAAAAAAAAAAAAAAA\"
    839     /// }")?.cross_origin);
    840     /// # Ok::<_, SerdeJsonErr>(())
    841     /// ```
    842     #[expect(single_use_lifetimes, reason = "false positive")]
    843     #[cfg_attr(docsrs, doc(cfg(feature = "serde_relaxed")))]
    844     #[cfg(feature = "serde_relaxed")]
    845     #[inline]
    846     pub fn from_client_data_json_relaxed<'b: 'a, const REGISTRATION: bool>(json: &'b [u8]) -> Result<Self, SerdeJsonErr> {
    847         ser_relaxed::RelaxedClientDataJsonParser::<REGISTRATION>::parse(json)
    848     }
    849 }
    850 /// Parser of 
    851 /// [`JSON-compatible serialization of client data`](https://www.w3.org/TR/webauthn-3/#collectedclientdata-json-compatible-serialization-of-client-data).
    852 trait ClientDataJsonParser {
    853     /// Error returned by [`Self::parse`].
    854     type Err;
    855     /// Parses `json` into `CollectedClientData` based on the value of
    856     /// [`type`](https://www.w3.org/TR/webauthn-3/#dom-collectedclientdata-type).
    857     ///
    858     /// # Errors
    859     ///
    860     /// Errors iff `json` cannot be parsed into a `CollectedClientData`.
    861     fn parse(json: &[u8]) -> Result<CollectedClientData<'_>, Self::Err>;
    862     /// Extracts [`challenge`](https://www.w3.org/TR/webauthn-3/#dom-collectedclientdata-challenge)
    863     /// from `json`.
    864     ///
    865     /// Note `json` should be minimally parsed such that only `challenge` is extracted; thus
    866     /// `Ok` being returned does _not_ mean `json` is in fact valid.
    867     fn get_sent_challenge(json: &[u8]) -> Result<SentChallenge, Self::Err>;
    868 }
    869 /// [`ClientDataJsonParser`] based on the
    870 /// [limited verification algorithm](https://www.w3.org/TR/webauthn-3/#clientdatajson-verification)
    871 /// with the following additional requirements:
    872 /// * Unknown keys are not allowed.
    873 /// * The entire payload is parsed; thus the payload is guaranteed to be valid UTF-8 and JSON.
    874 /// * [`CollectedClientData::top_origin`] can only be `Some` if
    875 ///   [`crossOrigin`](https://www.w3.org/TR/webauthn-3/#dom-collectedclientdata-crossorigin).
    876 /// * If `CollectedClientData::top_origin` is `Some`, then it does not equal [`CollectedClientData::origin`].
    877 ///
    878 /// `REGISTRATION` iff [`ClientDataJsonParser::parse`] requires
    879 /// [`type`](https://www.w3.org/TR/webauthn-3/#dom-collectedclientdata-type) to be `"webauthn.create"`;
    880 /// otherwise it must be `"webauthn.get"`.
    881 struct LimitedVerificationParser<const REGISTRATION: bool>;
    882 impl<const R: bool> LimitedVerificationParser<R> {
    883     /// Parses `val` as a JSON string with possibly trailing data. `val` MUST NOT begin with an opening quote. Upon
    884     /// encountering the first non-escaped quote, the parsed value is returned in addition to the remaining
    885     /// portion of `val` _after_ the closing quote. The limited verification algorithm is adhered to; thus the
    886     /// _only_ Unicode scalar values that are allowed (and must) be hex-escaped are U+0000 to U+001F inclusively.
    887     /// Similarly only `b'\\'` and `b'"'` are allowed (and must) be escaped with `b'\\'`.
    888     #[expect(unsafe_code, reason = "comment justifies its correctness")] 
    889     #[expect(clippy::arithmetic_side_effects, clippy::indexing_slicing, reason = "comments justify their correctness")]
    890     fn parse_string(val: &[u8]) -> Result<(Cow<'_, str>, &'_ [u8]), CollectedClientDataErr> {
    891         /// Tracks the state of the current Unicode scalar value that is being parsed.
    892         enum State {
    893             /// We are not parsing `'"'`, `'\\'`, or U+0000 to U+001F.
    894             Normal,
    895             /// We just encountered the escape character.
    896             Escape,
    897             /// We just encountered `b"\\u"`.
    898             UnicodeEscape,
    899             /// We just encountered `b"\\u0"`.
    900             UnicodeHex1,
    901             /// We just encountered `b"\\u00"`.
    902             UnicodeHex2,
    903             /// We just encountered `b"\\u000"` or `b"\\u001"`. The contained `u8` is `0` iff the former; otherwise
    904             /// `0x10`.
    905             UnicodeHex3(u8),
    906         }
    907         // We parse this as UTF-8 only at the end iff it is not empty. This contains all the potential Unicode scalar
    908         // values after de-escaping.
    909         let mut utf8 = Vec::new();
    910         // We check for all `u8`s already; thus we might as well check if we encounter a non-ASCII `u8`.
    911         // If we don't, then we can rely on `str::from_utf8_unchecked`.
    912         let mut all_ascii = true;
    913         // This tracks the start index of the next slice to add. We add slices iff we encounter the escape character or
    914         // we return the parsed `Cow` (i.e., encounter an unescaped `b'"'`).
    915         let mut cur_idx = 0;
    916         // The state of the yet-to-be-parsed Unicode scalar value.
    917         let mut state = State::Normal;
    918         for (counter, &b) in val.iter().enumerate() {
    919             match state {
    920                 State::Normal => {
    921                     match b {
    922                         b'"' => {
    923                             if utf8.is_empty() {
    924                                 if all_ascii {
    925                                     // `cur_idx` is 0 or 1. The latter is true iff `val` starts with a
    926                                     // `b'\\'` or `b'"'` but contains no other escaped characters.
    927                                     let s = &val[cur_idx..counter];
    928                                     // SAFETY:
    929                                     // `all_ascii` is `false` iff we encountered any `u8` that was not
    930                                     // an ASCII `u8`; thus we know `s` is valid ASCII which in turn means
    931                                     // it's valid UTF-8.
    932                                     let v = unsafe { str::from_utf8_unchecked(s) };
    933                                     // `val.len() > counter`, so indexing is fine and overflow cannot happen.
    934                                     return Ok((Cow::Borrowed(v), &val[counter + 1..]));
    935                                 }
    936                                 // `cur_idx` is 0 or 1. The latter is true iff `val` starts with a
    937                                 // `b'\\'` or `b'"'` but contains no other escaped characters.
    938                                 return str::from_utf8(&val[cur_idx..counter])
    939                                     .map_err(CollectedClientDataErr::Utf8)
    940                                     // `val.len() > counter`, so indexing is fine and overflow cannot happen.
    941                                     .map(|v| (Cow::Borrowed(v), &val[counter + 1..]));
    942                             }
    943                             // `val.len() > counter && counter >= cur_idx`, so indexing is fine and overflow
    944                             // cannot happen.
    945                             utf8.extend_from_slice(&val[cur_idx..counter]);
    946                             if all_ascii {
    947                                 // SAFETY:
    948                                 // `all_ascii` is `false` iff we encountered any `u8` that was not
    949                                 // an ASCII `u8`; thus we know `utf8` is valid ASCII which in turn means
    950                                 // it's valid UTF-8.
    951                                 let v = unsafe { String::from_utf8_unchecked(utf8) };
    952                                 // `val.len() > counter`, so indexing is fine and overflow cannot happen.
    953                                 return Ok((Cow::Owned(v), &val[counter + 1..]));
    954                             }
    955                             return String::from_utf8(utf8)
    956                                 .map_err(CollectedClientDataErr::Utf8Owned)
    957                                 // `val.len() > counter`, so indexing is fine and overflow cannot happen.
    958                                 .map(|v| (Cow::Owned(v), &val[counter + 1..]));
    959                         }
    960                         b'\\' => {
    961                             // Write the current slice of data.
    962                             utf8.extend_from_slice(&val[cur_idx..counter]);
    963                             state = State::Escape;
    964                         }
    965                         // ASCII is a subset of UTF-8 and this is a subset of ASCII. The code unit that is used for an
    966                         // ASCII Unicode scalar value _never_ appears in multi-code-unit Unicode scalar values; thus we
    967                         // error immediately.
    968                         ..=0x1f => return Err(CollectedClientDataErr::InvalidEscapedString),
    969                         128.. => all_ascii = false,
    970                         _ => (),
    971                     }
    972                 }
    973                 State::Escape => {
    974                     match b {
    975                         b'"' | b'\\' => {
    976                             // We start the next slice here since we need to add it.
    977                             cur_idx = counter;
    978                             state = State::Normal;
    979                         }
    980                         b'u' => {
    981                             state = State::UnicodeEscape;
    982                         }
    983                         _ => {
    984                             return Err(CollectedClientDataErr::InvalidEscapedString);
    985                         }
    986                     }
    987                 }
    988                 State::UnicodeEscape => {
    989                     if b != b'0' {
    990                         return Err(CollectedClientDataErr::InvalidEscapedString);
    991                     }
    992                     state = State::UnicodeHex1;
    993                 }
    994                 State::UnicodeHex1 => {
    995                     if b != b'0' {
    996                         return Err(CollectedClientDataErr::InvalidEscapedString);
    997                     }
    998                     state = State::UnicodeHex2;
    999                 }
   1000                 State::UnicodeHex2 => {
   1001                     state = State::UnicodeHex3(match b {
   1002                         b'0' => 0,
   1003                         b'1' => 0x10,
   1004                         _ => return Err(CollectedClientDataErr::InvalidEscapedString),
   1005                     });
   1006                 }
   1007                 State::UnicodeHex3(v) => {
   1008                     match b {
   1009                         // Only and all _lowercase_ hex is allowed.
   1010                         b'0'..=b'9' | b'a'..=b'f' => {
   1011                             // When `b < b'a'`, then `b >= b'0'`; and `b'a' > 87`; thus underflow cannot happen.
   1012                             // Note `b'a' - 10 == 87`.
   1013                             utf8.push(v | (b - if b < b'a' { b'0' } else { 87 }));
   1014                             // `counter < val.len()`, so overflow cannot happen.
   1015                             cur_idx = counter + 1;
   1016                             state = State::Normal;
   1017                         }
   1018                         _ => return Err(CollectedClientDataErr::InvalidEscapedString),
   1019                     }
   1020                 }
   1021             }
   1022         }
   1023         // We never encountered an unescaped `b'"'`; thus we could not parse a string.
   1024         Err(CollectedClientDataErr::InvalidObject)
   1025     }
   1026 }
   1027 impl<const R: bool> ClientDataJsonParser for LimitedVerificationParser<R> {
   1028     type Err = CollectedClientDataErr;
   1029     #[expect(clippy::panic_in_result_fn, reason = "want to crash when there is a bug")]
   1030     #[expect(clippy::little_endian_bytes, reason = "Challenge::serialize and this need to be consistent across architectures")]
   1031     #[expect(clippy::too_many_lines, reason = "110 lines is fine")]
   1032     fn parse(json: &[u8]) -> Result<CollectedClientData<'_>, Self::Err> {
   1033         // `{"type":"webauthn.<create|get>","challenge":"<22 bytes>","origin":"<bytes>","crossOrigin":<true|false>[,"topOrigin":"<bytes>"][,<anything>]}`.
   1034         /// First portion of `value`.
   1035         const HEADER: &[u8; 18] = br#"{"type":"webauthn."#;
   1036         /// `get`.
   1037         const GET: &[u8; 3] = b"get";
   1038         /// `create`.
   1039         const CREATE: &[u8; 6] = b"create";
   1040         /// Value after type before the start of the base64url-encoded challenge.
   1041         const AFTER_TYPE: &[u8; 15] = br#"","challenge":""#;
   1042         /// Value after challenge before the start of the origin value.
   1043         const AFTER_CHALLENGE: &[u8; 12] = br#"","origin":""#;
   1044         /// Value after origin before the start of the crossOrigin value.
   1045         const AFTER_ORIGIN: &[u8; 15] = br#","crossOrigin":"#;
   1046         /// `true`.
   1047         const TRUE: &[u8; 4] = b"true";
   1048         /// `false`.
   1049         const FALSE: &[u8; 5] = b"false";
   1050         /// Value after crossOrigin before the start of the topOrigin value.
   1051         const AFTER_CROSS: &[u8; 13] = br#""topOrigin":""#;
   1052         json.split_last().ok_or(CollectedClientDataErr::Len).and_then(|(last, last_rem)| {
   1053             if *last == b'}' {
   1054                 last_rem.split_at_checked(HEADER.len()).ok_or(CollectedClientDataErr::Len).and_then(|(header, header_rem)| {
   1055                     if header == HEADER {
   1056                         if R {
   1057                             header_rem.split_at_checked(CREATE.len()).ok_or(CollectedClientDataErr::Len).and_then(|(create, create_rem)| {
   1058                                 if create == CREATE {
   1059                                     Ok(create_rem)
   1060                                 } else {
   1061                                     Err(CollectedClientDataErr::Type)
   1062                                 }
   1063                             })
   1064                         } else {
   1065                             header_rem.split_at_checked(GET.len()).ok_or(CollectedClientDataErr::Len).and_then(|(get, get_rem)| {
   1066                                 if get == GET {
   1067                                     Ok(get_rem)
   1068                                 } else {
   1069                                     Err(CollectedClientDataErr::Type)
   1070                                 }
   1071                             })
   1072                         }.and_then(|type_rem| {
   1073                             type_rem.split_at_checked(AFTER_TYPE.len()).ok_or(CollectedClientDataErr::Len).and_then(|(chall_key, chall_key_rem)| {
   1074                                 if chall_key == AFTER_TYPE {
   1075                                     chall_key_rem.split_at_checked(Challenge::BASE64_LEN).ok_or(CollectedClientDataErr::Len).and_then(|(base64_chall, base64_chall_rem)| {
   1076                                         let mut chall = [0; 16];
   1077                                         BASE64URL_NOPAD.decode_mut(base64_chall, chall.as_mut_slice()).map_err(|_e| CollectedClientDataErr::Challenge).and_then(|chall_len| {
   1078                                             assert_eq!(chall_len, 16, "there is a bug in BASE64URL_NOPAD::decode_mut");
   1079                                             base64_chall_rem.split_at_checked(AFTER_CHALLENGE.len()).ok_or(CollectedClientDataErr::Len).and_then(|(origin_key, origin_key_rem)| {
   1080                                                 if origin_key == AFTER_CHALLENGE {
   1081                                                     Self::parse_string(origin_key_rem).and_then(|(origin, origin_rem)| {
   1082                                                         origin_rem.split_at_checked(AFTER_ORIGIN.len()).ok_or(CollectedClientDataErr::Len).and_then(|(cross_key, cross_key_rem)| {
   1083                                                             if cross_key == AFTER_ORIGIN {
   1084                                                                 // `FALSE.len() > TRUE.len()`, so we check for `FALSE` in `and_then`.
   1085                                                                 cross_key_rem.split_at_checked(TRUE.len()).ok_or(CollectedClientDataErr::Len).and_then(|(cross_true, cross_true_rem)| {
   1086                                                                     if cross_true == TRUE {
   1087                                                                         Ok((true, cross_true_rem))
   1088                                                                     } else {
   1089                                                                         cross_key_rem.split_at_checked(FALSE.len()).ok_or(CollectedClientDataErr::Len).and_then(|(cross_false, cross_false_rem)| {
   1090                                                                             if cross_false == FALSE {
   1091                                                                                 Ok((false, cross_false_rem))
   1092                                                                             } else {
   1093                                                                                 Err(CollectedClientDataErr::CrossOrigin)
   1094                                                                             }
   1095                                                                         })
   1096                                                                     }.and_then(|(cross, cross_rem)| {
   1097                                                                         cross_rem.split_first().map_or(Ok((cross, None)), |(comma, comma_rem)| {
   1098                                                                             if *comma == b',' {
   1099                                                                                 comma_rem.split_at_checked(AFTER_CROSS.len()).map_or(Ok((cross, None)), |(top, top_rem)| {
   1100                                                                                     if top == AFTER_CROSS {
   1101                                                                                         if cross {
   1102                                                                                             Self::parse_string(top_rem).and_then(|(top_origin, top_origin_rem)| {
   1103                                                                                                 top_origin_rem.first().map_or(Ok(()), |v| {
   1104                                                                                                     if *v == b',' {
   1105                                                                                                         Ok(())
   1106                                                                                                     } else {
   1107                                                                                                         Err(CollectedClientDataErr::InvalidObject)
   1108                                                                                                     }
   1109                                                                                                 }).and_then(|()| {
   1110                                                                                                     if origin == top_origin {
   1111                                                                                                         Err(CollectedClientDataErr::TopOriginSameAsOrigin)
   1112                                                                                                     } else {
   1113                                                                                                         Ok((true, Some(Origin(top_origin))))
   1114                                                                                                     }
   1115                                                                                                 })
   1116                                                                                             })
   1117                                                                                         } else {
   1118                                                                                             Err(CollectedClientDataErr::TopOriginWithoutCrossOrigin)
   1119                                                                                         }
   1120                                                                                     } else {
   1121                                                                                         Ok((cross, None))
   1122                                                                                     }
   1123                                                                                 })
   1124                                                                             } else {
   1125                                                                                 Err(CollectedClientDataErr::InvalidObject)
   1126                                                                             }
   1127                                                                         }).map(|(cross_origin, top_origin)| CollectedClientData { challenge: SentChallenge(u128::from_le_bytes(chall)), origin: Origin(origin), cross_origin, top_origin, })
   1128                                                                     })
   1129                                                                 })
   1130                                                             } else {
   1131                                                                 Err(CollectedClientDataErr::CrossOriginKey)
   1132                                                             }
   1133                                                         })
   1134                                                     })
   1135                                                 } else {
   1136                                                     Err(CollectedClientDataErr::OriginKey)
   1137                                                 }
   1138                                             })
   1139                                         })
   1140                                     })
   1141                                 } else {
   1142                                     Err(CollectedClientDataErr::ChallengeKey)
   1143                                 }
   1144                             })
   1145                         })
   1146                     } else {
   1147                         Err(CollectedClientDataErr::InvalidStart)
   1148                     }
   1149                 })
   1150             } else {
   1151                 Err(CollectedClientDataErr::InvalidObject)
   1152             }
   1153         })
   1154     }
   1155     #[expect(clippy::panic_in_result_fn, reason = "want to crash when there is a bug")]
   1156     #[expect(clippy::arithmetic_side_effects, reason = "comment justifies correctness")]
   1157     #[expect(clippy::little_endian_bytes, reason = "Challenge::serialize and this need to be consistent across architectures")]
   1158     fn get_sent_challenge(json: &[u8]) -> Result<SentChallenge, Self::Err> {
   1159         // Index 39.
   1160         // `{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAAA"...`.
   1161         // Index 36.
   1162         // `{"type":"webauthn.get","challenge":"AAAAAAAAAAAAAAAAAAAAAA"...`.
   1163         let idx = if R { 39 } else { 36 };
   1164         // This maxes at 39 + 22 = 61; thus overflow is not an issue.
   1165         json.get(idx..idx + Challenge::BASE64_LEN).ok_or(CollectedClientDataErr::Len).and_then(|chall_slice| {
   1166             let mut chall = [0; 16];
   1167             BASE64URL_NOPAD.decode_mut(chall_slice, chall.as_mut_slice()).map_err(|_e| CollectedClientDataErr::Challenge).map(|len| {
   1168                 assert_eq!(len, 16, "there is a bug in BASE64URL_NOPAD::decode_mut");
   1169                 SentChallenge(u128::from_le_bytes(chall))
   1170             })
   1171         })
   1172     }
   1173 }
   1174 /// Authenticator extension outputs;
   1175 pub(super) trait AuthExtOutput {
   1176     /// MUST return `true` iff there is no data.
   1177     fn missing(self) -> bool;
   1178 }
   1179 /// Successful return type from [`FromCbor::from_cbor`].
   1180 struct CborSuccess<'a, T> {
   1181     /// Value parsed from the slice.
   1182     value: T,
   1183     /// Remaining unprocessed data.
   1184     remaining: &'a [u8],
   1185 }
   1186 /// Types that parse
   1187 /// [CTAP2 canonical CBOR encoding form](https://fidoalliance.org/specs/fido-v2.2-rd-20230321/fido-client-to-authenticator-protocol-v2.2-rd-20230321.html#ctap2-canonical-cbor-encoding-form)
   1188 /// data without necessarily consuming all the data.
   1189 ///
   1190 /// The purpose of this `trait` is to allow chains of types to progressively consume `cbor` by passing
   1191 /// [`CborSuccess::remaining`] into the next `FromCbor` type.
   1192 trait FromCbor<'a>: Sized {
   1193     /// Error when conversion fails.
   1194     type Err;
   1195     /// Parses `cbor` into `Self`.
   1196     ///
   1197     /// # Errors
   1198     ///
   1199     /// Errors if `cbor` cannot be parsed into `Self:`.
   1200     fn from_cbor(cbor: &'a [u8]) -> Result<CborSuccess<'a, Self>, Self::Err>;
   1201 }
   1202 /// Error returned from [`A::from_cbor`] `where A: AuthData`.
   1203 enum AuthenticatorDataErr<UpErr, CredData, AuthExt> {
   1204     /// The `slice` had an invalid length.
   1205     Len,
   1206     /// [UP](https://www.w3.org/TR/webauthn-3/#authdata-flags-at) bit was 0.
   1207     UserNotPresent(UpErr),
   1208     /// Bit 1 in [`flags`](https://www.w3.org/TR/webauthn-3/#authdata-flags) is not 0.
   1209     FlagsBit1Not0,
   1210     /// Bit 5 in [`flags`](https://www.w3.org/TR/webauthn-3/#authdata-flags) is not 0.
   1211     FlagsBit5Not0,
   1212     /// [AT](https://www.w3.org/TR/webauthn-3/#authdata-flags-at) bit was 0 during registration or was 1
   1213     /// during authentication.
   1214     AttestedCredentialData,
   1215     /// [BE](https://www.w3.org/TR/webauthn-3/#authdata-flags-be) and
   1216     /// [BS](https://www.w3.org/TR/webauthn-3/#authdata-flags-bs) bits were 0 and 1 respectively.
   1217     BackupWithoutEligibility,
   1218     /// Error returned from [`AttestedCredentialData::from_cbor`].
   1219     AttestedCredential(CredData),
   1220     /// Error returned from [`register::AuthenticatorExtensionOutput::from_cbor`] and
   1221     /// [`auth::AuthenticatorExtensionOutput::from_cbor`].
   1222     AuthenticatorExtension(AuthExt),
   1223     /// [ED](https://www.w3.org/TR/webauthn-3/#authdata-flags-ed) bit was 0, but
   1224     /// [`extensions`](https://www.w3.org/TR/webauthn-3/#authdata-extensions) existed.
   1225     NoExtensionBitWithData,
   1226     /// [ED](https://www.w3.org/TR/webauthn-3/#authdata-flags-ed) bit was 1, but
   1227     /// [`extensions`](https://www.w3.org/TR/webauthn-3/#authdata-extensions) did not exist.
   1228     ExtensionBitWithoutData,
   1229     /// There was trailing data that could not be deserialized.
   1230     TrailingData,
   1231 }
   1232 impl<U, C: Display, A: Display> Display for AuthenticatorDataErr<U, C, A> {
   1233     fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
   1234         match *self {
   1235             Self::Len => f.write_str("authenticator data had an invalid length"),
   1236             Self::UserNotPresent(_) => f.write_str("user was not present"),
   1237             Self::FlagsBit1Not0 => f.write_str("flags 1-bit was 1"),
   1238             Self::FlagsBit5Not0 => f.write_str("flags 5-bit was 1"),
   1239             Self::AttestedCredentialData => f.write_str("attested credential data was included during authentication or was not included during registration"),
   1240             Self::BackupWithoutEligibility => {
   1241                 f.write_str("backup state bit was 1 despite backup eligibility being 0")
   1242             }
   1243             Self::AttestedCredential(ref err) => err.fmt(f),
   1244             Self::AuthenticatorExtension(ref err) => err.fmt(f),
   1245             Self::NoExtensionBitWithData => {
   1246                 f.write_str("extension bit was 0 despite extensions existing")
   1247             }
   1248             Self::ExtensionBitWithoutData => {
   1249                 f.write_str("extension bit was 1 despite no extensions existing")
   1250             }
   1251             Self::TrailingData => {
   1252                 f.write_str("slice had trailing data that could not be deserialized")
   1253             }
   1254         }
   1255     }
   1256 }
   1257 impl From<AuthenticatorDataErr<Infallible, AttestedCredentialDataErr, RegAuthExtErr>> for RegAuthDataErr {
   1258     #[inline]
   1259     fn from(value: AuthenticatorDataErr<Infallible, AttestedCredentialDataErr, RegAuthExtErr>) -> Self {
   1260         match value {
   1261             AuthenticatorDataErr::Len => Self::Len,
   1262             AuthenticatorDataErr::UserNotPresent(v) => match v {},
   1263             AuthenticatorDataErr::FlagsBit1Not0 => Self::FlagsBit1Not0,
   1264             AuthenticatorDataErr::FlagsBit5Not0 => Self::FlagsBit5Not0,
   1265             AuthenticatorDataErr::AttestedCredentialData => Self::AttestedCredentialDataNotIncluded,
   1266             AuthenticatorDataErr::BackupWithoutEligibility => Self::BackupWithoutEligibility,
   1267             AuthenticatorDataErr::AttestedCredential(err) => Self::AttestedCredential(err),
   1268             AuthenticatorDataErr::AuthenticatorExtension(err) => Self::AuthenticatorExtension(err),
   1269             AuthenticatorDataErr::NoExtensionBitWithData => Self::NoExtensionBitWithData,
   1270             AuthenticatorDataErr::ExtensionBitWithoutData => Self::ExtensionBitWithoutData,
   1271             AuthenticatorDataErr::TrailingData => Self::TrailingData,
   1272         }
   1273     }
   1274 }
   1275 impl From<AuthenticatorDataErr<(), Infallible, AuthAuthExtErr>> for AuthAuthDataErr {
   1276     #[inline]
   1277     fn from(value: AuthenticatorDataErr<(), Infallible, AuthAuthExtErr>) -> Self {
   1278         match value {
   1279             AuthenticatorDataErr::Len => Self::Len,
   1280             AuthenticatorDataErr::UserNotPresent(()) => Self::UserNotPresent,
   1281             AuthenticatorDataErr::FlagsBit1Not0 => Self::FlagsBit1Not0,
   1282             AuthenticatorDataErr::FlagsBit5Not0 => Self::FlagsBit5Not0,
   1283             AuthenticatorDataErr::AttestedCredentialData => Self::AttestedCredentialDataIncluded,
   1284             AuthenticatorDataErr::AttestedCredential(val) => match val {},
   1285             AuthenticatorDataErr::BackupWithoutEligibility => Self::BackupWithoutEligibility,
   1286             AuthenticatorDataErr::AuthenticatorExtension(err) => Self::AuthenticatorExtension(err),
   1287             AuthenticatorDataErr::NoExtensionBitWithData => Self::NoExtensionBitWithData,
   1288             AuthenticatorDataErr::ExtensionBitWithoutData => Self::ExtensionBitWithoutData,
   1289             AuthenticatorDataErr::TrailingData => Self::TrailingData,
   1290         }
   1291     }
   1292 }
   1293 impl<'a, A> FromCbor<'a> for A
   1294 where
   1295     A: AuthData<'a>,
   1296     A::CredData: FromCbor<'a>,
   1297     A::Ext: FromCbor<'a>,
   1298 {
   1299     type Err = AuthenticatorDataErr<A::UpBitErr, <A::CredData as FromCbor<'a>>::Err, <A::Ext as FromCbor<'a>>::Err>;
   1300     #[expect(clippy::big_endian_bytes, reason = "CBOR integers are in big-endian")]
   1301     fn from_cbor(cbor: &'a [u8]) -> Result<CborSuccess<'a, Self>, Self::Err> {
   1302         /// Length of `signCount`.
   1303         const SIGN_COUNT_LEN: usize = 4;
   1304         /// `UP` bit (i.e., bit 0) set to 1.
   1305         const UP: u8 = 0b0000_0001;
   1306         /// `RFU1` bit (i.e., bit 1) set to 1.
   1307         const RFU1: u8 = UP << 1;
   1308         /// `UV` bit (i.e., bit 2) set to 1.
   1309         const UV: u8 = RFU1 << 1;
   1310         /// `BE` bit (i.e., bit 3) set to 1.
   1311         const BE: u8 = UV << 1;
   1312         /// `BS` bit (i.e., bit 4) set to 1.
   1313         const BS: u8 = BE << 1;
   1314         /// `RFU2` bit (i.e., bit 5) set to 1.
   1315         const RFU2: u8 = BS << 1;
   1316         /// `AT` bit (i.e., bit 6) set to 1.
   1317         const AT: u8 = RFU2 << 1;
   1318         /// `ED` bit (i.e., bit 7) set to 1.
   1319         const ED: u8 = AT << 1;
   1320         cbor.split_at_checked(Sha256::output_size()).ok_or_else(|| AuthenticatorDataErr::Len).and_then(|(rp_id_slice, rp_id_rem)| {
   1321             rp_id_rem.split_first().ok_or_else(|| AuthenticatorDataErr::Len).and_then(|(&flag, flag_rem)| {
   1322                 let user_present = flag & UP == UP;
   1323                 if user_present {
   1324                     Ok(())
   1325                 } else {
   1326                     A::user_is_not_present().map_err(AuthenticatorDataErr::UserNotPresent)   
   1327                 }
   1328                 .and_then(|()| {
   1329                     if flag & RFU1 == 0 {
   1330                         if flag & RFU2 == 0 {
   1331                             let at_bit = A::contains_at_bit();
   1332                             if flag & AT == AT {
   1333                                 if at_bit {
   1334                                     Ok(())
   1335                                 } else {
   1336                                     Err(AuthenticatorDataErr::AttestedCredentialData)
   1337                                 }
   1338                             } else if at_bit {
   1339                                 Err(AuthenticatorDataErr::AttestedCredentialData)
   1340                             } else {
   1341                                 Ok(())
   1342                             }.and_then(|()| {
   1343                                 let bs = flag & BS == BS;
   1344                                 if flag & BE == BE {
   1345                                     if bs {
   1346                                         Ok(Backup::Exists)
   1347                                     } else {
   1348                                         Ok(Backup::Eligible)
   1349                                     }
   1350                                 } else if bs {
   1351                                     Err(AuthenticatorDataErr::BackupWithoutEligibility)
   1352                                 } else {
   1353                                     Ok(Backup::NotEligible)
   1354                                 }
   1355                                 .and_then(|backup| {
   1356                                     flag_rem.split_at_checked(SIGN_COUNT_LEN).ok_or_else(|| AuthenticatorDataErr::Len).and_then(|(count_slice, count_rem)| {
   1357                                         A::CredData::from_cbor(count_rem).map_err(AuthenticatorDataErr::AttestedCredential).and_then(|att_data| {
   1358                                             A::Ext::from_cbor(att_data.remaining).map_err(AuthenticatorDataErr::AuthenticatorExtension).and_then(|ext| {
   1359                                                 if ext.remaining.is_empty() {
   1360                                                     let ed = flag & ED == ED;
   1361                                                     if ext.value.missing() {
   1362                                                         if ed {
   1363                                                             Err(AuthenticatorDataErr::ExtensionBitWithoutData)
   1364                                                         } else {
   1365                                                             Ok(())
   1366                                                         }
   1367                                                     } else if ed {
   1368                                                         Ok(())
   1369                                                     } else {
   1370                                                         Err(AuthenticatorDataErr::NoExtensionBitWithData)
   1371                                                     }.map(|()| {
   1372                                                         let mut sign_count = [0; SIGN_COUNT_LEN];
   1373                                                         sign_count.copy_from_slice(count_slice);
   1374                                                         // `signCount` is in big-endian.
   1375                                                         CborSuccess { value: A::new(rp_id_slice, Flag { user_present, user_verified: flag & UV == UV, backup, }, u32::from_be_bytes(sign_count), att_data.value, ext.value), remaining: ext.remaining, }
   1376                                                     })
   1377                                                 } else {
   1378                                                     Err(AuthenticatorDataErr::TrailingData)
   1379                                                 }
   1380                                             })
   1381                                         })
   1382                                     })
   1383                                 })
   1384                             })
   1385                         } else {
   1386                             Err(AuthenticatorDataErr::FlagsBit5Not0)
   1387                         }
   1388                     } else {
   1389                         Err(AuthenticatorDataErr::FlagsBit1Not0)
   1390                     }
   1391                 })
   1392             })
   1393         })
   1394     }
   1395 }
   1396 /// Data returned by [`AuthDataContainer::from_data`].
   1397 pub(super) struct ParsedAuthData<'a, A> {
   1398     /// The data the CBOR is parsed into.
   1399     data: A,
   1400     /// The raw authenticator data and 32-bytes of trailing data.
   1401     auth_data_and_32_trailing_bytes: &'a [u8],
   1402 }
   1403 /// Error returned by [`AuthResponse::parse_data_and_verify_sig`].
   1404 pub(super) enum AuthRespErr<AuthDataErr> {
   1405     /// Variant returned when parsing
   1406     /// [`clientDataJSON`](https://www.w3.org/TR/webauthn-3/#dom-authenticatorresponse-clientdatajson)
   1407     /// into [`CollectedClientData`] fails.
   1408     CollectedClientData(CollectedClientDataErr),
   1409     /// Variant returned when parsing
   1410     /// [`clientDataJSON`](https://www.w3.org/TR/webauthn-3/#dom-authenticatorresponse-clientdatajson)
   1411     /// in a "relaxed" way into [`CollectedClientData`] fails.
   1412     #[cfg(feature = "serde_relaxed")]
   1413     CollectedClientDataRelaxed(SerdeJsonErr),
   1414     /// Variant returned when parsing [`AuthResponse::Auth`] fails.
   1415     Auth(AuthDataErr),
   1416     /// Variant when the [`CompressedPubKey`] or [`UncompressePubKey`] is not valid.
   1417     PubKey(PubKeyErr),
   1418     /// Variant returned when the signature, if one exists, associated with
   1419     /// [`Self::AuthResponse`] is invalid.
   1420     Signature,
   1421 }
   1422 impl<A: Display> Display for AuthRespErr<A> {
   1423     fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
   1424         match *self {
   1425             Self::CollectedClientData(ref err) => write!(f, "CollectedClientData could not be parsed: {err}"),
   1426             #[cfg(feature = "serde_relaxed")]
   1427             Self::CollectedClientDataRelaxed(ref err) => write!(f, "CollectedClientData could not be parsed: {err}"),
   1428             Self::Auth(ref err) => write!(f, "auth data could not be parsed: {err}"),
   1429             Self::PubKey(err) => err.fmt(f),
   1430             Self::Signature => f.write_str("the signature over the authenticator data and CollectedClientData could not be verified"),
   1431         }
   1432     }
   1433 }
   1434 impl From<AuthRespErr<AttestationObjectErr>> for RegCeremonyErr {
   1435     #[inline]
   1436     fn from(value: AuthRespErr<AttestationObjectErr>) -> Self {
   1437         match value {
   1438             AuthRespErr::CollectedClientData(err) => Self::CollectedClientData(err),
   1439             #[cfg(feature = "serde_relaxed")]
   1440             AuthRespErr::CollectedClientDataRelaxed(err) => Self::CollectedClientDataRelaxed(err),
   1441             AuthRespErr::Auth(err) => Self::AttestationObject(err),
   1442             AuthRespErr::PubKey(err) => Self::PubKey(err),
   1443             AuthRespErr::Signature => Self::AttestationSignature,
   1444         }
   1445     }
   1446 }
   1447 impl From<AuthRespErr<AuthAuthDataErr>> for AuthCeremonyErr {
   1448     #[inline]
   1449     fn from(value: AuthRespErr<AuthAuthDataErr>) -> Self {
   1450         match value {
   1451             AuthRespErr::CollectedClientData(err) => Self::CollectedClientData(err),
   1452             #[cfg(feature = "serde_relaxed")]
   1453             AuthRespErr::CollectedClientDataRelaxed(err) => Self::CollectedClientDataRelaxed(err),
   1454             AuthRespErr::Auth(err) => Self::AuthenticatorData(err),
   1455             AuthRespErr::PubKey(err) => Self::PubKey(err),
   1456             AuthRespErr::Signature => Self::AssertionSignature,
   1457         }
   1458     }
   1459 }
   1460 /// [Authenticator data](https://www.w3.org/TR/webauthn-3/#authenticator-data)
   1461 /// container.
   1462 ///
   1463 /// Note [`Self::Auth`] may be `Self`.
   1464 pub(super) trait AuthDataContainer<'a>: Sized {
   1465     /// [Authenticator data](https://www.w3.org/TR/webauthn-3/#authenticator-data).
   1466     type Auth: AuthData<'a>;
   1467     /// Error returned from [`Self::from_data`].
   1468     type Err;
   1469     /// Converts `data` into [`ParsedAuthData`].
   1470     ///
   1471     /// # Errors
   1472     ///
   1473     /// Errors iff `data` cannot be converted into `ParsedAuthData`.
   1474     fn from_data(data: &'a [u8]) -> Result<ParsedAuthData<'a, Self>, Self::Err>;
   1475     /// Returns the contained
   1476     /// [authenticator data](https://www.w3.org/TR/webauthn-3/#authenticator-data).
   1477     fn authenticator_data(&self) -> &Self::Auth;
   1478 }
   1479 /// [`AuthenticatorResponse`](https://www.w3.org/TR/webauthn-3/#authenticatorresponse).
   1480 pub(super) trait AuthResponse {
   1481     /// [Attestation object](https://www.w3.org/TR/webauthn-3/#attestation-object) or
   1482     /// [authenticator data](https://www.w3.org/TR/webauthn-3/#authenticator-data).
   1483     type Auth<'a>: AuthDataContainer<'a> where Self: 'a;
   1484     /// Public key to use to verify the contained signature.
   1485     type CredKey<'a>;
   1486     /// Parses
   1487     /// [`clientDataJSON`](https://www.w3.org/TR/webauthn-3/#dom-authenticatorresponse-clientdatajson)
   1488     /// based on `RELAXED` and [`Self::Auth`] via [`AuthDataContainer::from_data`] in addition to
   1489     /// verifying any possible signature over the concatenation of the raw
   1490     /// [`AuthDataContainer::Auth`] and `clientDataJSON` using `key` or the contained
   1491     /// public key if one exists. If `Self` contains a public key and should not be passed one, then it should set
   1492     /// [`Self::CredKey`] to `()`.
   1493     ///
   1494     /// # Errors
   1495     ///
   1496     /// Errors iff parsing `clientDataJSON` errors, [`AuthDataContainer::from_data`] does, or the signature
   1497     /// is invalid.
   1498     ///
   1499     /// # Panics
   1500     ///
   1501     /// `panic`s iff `relaxed` and `serde_relaxed` is not enabled.
   1502     #[expect(
   1503         clippy::type_complexity,
   1504         reason = "type aliases with bounds are even more problematic at least until lazy_type_alias is stable"
   1505     )]
   1506     fn parse_data_and_verify_sig(&self, key: Self::CredKey<'_>, relaxed: bool) -> Result<(CollectedClientData<'_>, Self::Auth<'_>), AuthRespErr<<Self::Auth<'_> as AuthDataContainer<'_>>::Err>>;
   1507 }
   1508 /// Ceremony response (i.e., [`PublicKeyCredential`](https://www.w3.org/TR/webauthn-3/#publickeycredential)).
   1509 pub(super) trait Response {
   1510     /// [`AuthenticatorResponse`](https://www.w3.org/TR/webauthn-3/#authenticatorresponse).
   1511     type Auth: AuthResponse;
   1512     /// [`response`](https://www.w3.org/TR/webauthn-3/#dom-publickeycredential-response).
   1513     fn auth(&self) -> &Self::Auth;
   1514 }
   1515 /// Error returned from [`Ceremony::partial_validate`].
   1516 pub(super) enum CeremonyErr<AuthDataErr> {
   1517     /// Timeout occurred.
   1518     Timeout,
   1519     /// Read [`AuthRespErr`] for information.
   1520     AuthResp(AuthRespErr<AuthDataErr>),
   1521     /// Origin did not validate.
   1522     OriginMismatch,
   1523     /// Cross origin was `true` but was not allowed to be.
   1524     CrossOrigin,
   1525     /// Top origin did not validate.
   1526     TopOriginMismatch,
   1527     /// Challenges don't match.
   1528     ChallengeMismatch,
   1529     /// `rpIdHash` does not match the SHA-256 hash of the [`RpId`].
   1530     RpIdHashMismatch,
   1531     /// User was not verified despite being required to.
   1532     UserNotVerified,
   1533     /// [`Backup::NotEligible`] was not sent back despite [`BackupReq::NotEligible`].
   1534     BackupEligible,
   1535     /// [`Backup::NotEligible`] was sent back despite [`BackupReq::Eligible`].
   1536     BackupNotEligible,
   1537     /// [`Backup::Eligible`] was not sent back despite [`BackupReq::EligibleNoteExists`].
   1538     BackupExists,
   1539     /// [`Backup::Exists`] was not sent back despite [`BackupReq::Exists`].
   1540     BackupDoesNotExist,
   1541 }
   1542 impl<A: Display> Display for CeremonyErr<A> {
   1543     fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
   1544         match *self {
   1545             Self::Timeout => f.write_str("ceremony timed out"),
   1546             Self::AuthResp(ref err) => err.fmt(f),
   1547             Self::OriginMismatch => {
   1548                 f.write_str("the origin sent from the client is not an allowed origin")
   1549             }
   1550             Self::CrossOrigin => {
   1551                 f.write_str("cross origin was from the client, but it is not allowed")
   1552             }
   1553             Self::TopOriginMismatch => {
   1554                 f.write_str("the top origin sent from the client is not an allowed top origin")
   1555             }
   1556             Self::ChallengeMismatch => f.write_str(
   1557                 "the challenge sent to the client does not match the challenge sent back",
   1558             ),
   1559             Self::RpIdHashMismatch => f.write_str(
   1560                 "the SHA-256 hash of the RP ID doesn't match the hash sent from the client",
   1561             ),
   1562             Self::UserNotVerified => f.write_str("user was not verified despite being required to"),
   1563             Self::BackupEligible => f.write_str("credential is eligible to be backed up despite requiring that it not be"),
   1564             Self::BackupNotEligible => f.write_str("credential is not eligible to be backed up despite requiring that it be"),
   1565             Self::BackupExists => f.write_str("credential backup exists despite requiring that a backup not exist"),
   1566             Self::BackupDoesNotExist => f.write_str("credential backup does not exist despite requiring that a backup exist"),
   1567         }
   1568     }
   1569 }
   1570 impl From<CeremonyErr<AttestationObjectErr>> for RegCeremonyErr {
   1571     #[inline]
   1572     fn from(value: CeremonyErr<AttestationObjectErr>) -> Self {
   1573         match value {
   1574             CeremonyErr::Timeout => Self::Timeout,
   1575             CeremonyErr::AuthResp(err) => err.into(),
   1576             CeremonyErr::OriginMismatch => Self::OriginMismatch,
   1577             CeremonyErr::CrossOrigin => Self::CrossOrigin,
   1578             CeremonyErr::TopOriginMismatch => Self::TopOriginMismatch,
   1579             CeremonyErr::ChallengeMismatch => Self::ChallengeMismatch,
   1580             CeremonyErr::RpIdHashMismatch => Self::RpIdHashMismatch,
   1581             CeremonyErr::UserNotVerified => Self::UserNotVerified,
   1582             CeremonyErr::BackupEligible => Self::BackupEligible,
   1583             CeremonyErr::BackupNotEligible => Self::BackupNotEligible,
   1584             CeremonyErr::BackupExists => Self::BackupExists,
   1585             CeremonyErr::BackupDoesNotExist => Self::BackupDoesNotExist,
   1586         }
   1587     }
   1588 }
   1589 impl From<CeremonyErr<AuthAuthDataErr>> for AuthCeremonyErr {
   1590     #[inline]
   1591     fn from(value: CeremonyErr<AuthAuthDataErr>) -> Self {
   1592         match value {
   1593             CeremonyErr::Timeout => Self::Timeout,
   1594             CeremonyErr::AuthResp(err) => err.into(),
   1595             CeremonyErr::OriginMismatch => Self::OriginMismatch,
   1596             CeremonyErr::CrossOrigin => Self::CrossOrigin,
   1597             CeremonyErr::TopOriginMismatch => Self::TopOriginMismatch,
   1598             CeremonyErr::ChallengeMismatch => Self::ChallengeMismatch,
   1599             CeremonyErr::RpIdHashMismatch => Self::RpIdHashMismatch,
   1600             CeremonyErr::UserNotVerified => Self::UserNotVerified,
   1601             CeremonyErr::BackupEligible => Self::BackupEligible,
   1602             CeremonyErr::BackupNotEligible => Self::BackupNotEligible,
   1603             CeremonyErr::BackupExists => Self::BackupExists,
   1604             CeremonyErr::BackupDoesNotExist => Self::BackupDoesNotExist,
   1605         }
   1606     }
   1607 }
   1608 /// [`AllAcceptedCredentialsOptions`](https://www.w3.org/TR/webauthn-3/#dictdef-allacceptedcredentialsoptions).
   1609 ///
   1610 /// This can be sent to _an already authenticated user_ to inform what credentials are currently registered.
   1611 /// This can be useful when a user deletes credentials on the RP's side but does not do so on the authenticator.
   1612 /// When the client forwards this response to the authenticator, it can remove all credentials that don't have
   1613 /// a [`CredentialId`] in [`Self::all_accepted_credential_ids`].
   1614 #[derive(Debug)]
   1615 pub struct AllAcceptedCredentialsOptions<'rp, 'user, const USER_LEN: usize> {
   1616     /// [`rpId`](https://www.w3.org/TR/webauthn-3/#dictdef-allacceptedcredentialsoptions-rpid).
   1617     pub rp_id: &'rp RpId,
   1618     /// [`userId`](https://www.w3.org/TR/webauthn-3/#dictdef-allacceptedcredentialsoptions-userid).
   1619     pub user_id: &'user UserHandle<USER_LEN>,
   1620     /// [`allAcceptedCredentialIds`](https://www.w3.org/TR/webauthn-3/#dictdef-allacceptedcredentialsoptions-allacceptedcredentialids).
   1621     pub all_accepted_credential_ids: Vec<CredentialId<Vec<u8>>>,
   1622 }
   1623 /// [`CurrentUserDetailsOptions`](https://www.w3.org/TR/webauthn-3/#dictdef-currentuserdetailsoptions).
   1624 ///
   1625 /// This can be sent to _an already authenticated user_ to inform the user information.
   1626 /// This can be useful when a user updates their user information on the RP's side but does not do so on the authenticator.
   1627 /// When the client forwards this response to the authenticator, it can update the user info for the associated credential.
   1628 #[derive(Debug)]
   1629 pub struct CurrentUserDetailsOptions<'rp_id, 'name, 'display_name, 'id, const LEN: usize> {
   1630     /// [`rpId`](https://www.w3.org/TR/webauthn-3/#dictdef-currentuserdetailsoptions-rpid).
   1631     pub rp_id: &'rp_id RpId,
   1632     /// [`userId`](https://www.w3.org/TR/webauthn-3/#dictdef-currentuserdetailsoptions-userid),
   1633     /// [`name`](https://www.w3.org/TR/webauthn-3/#dictdef-currentuserdetailsoptions-name), and
   1634     /// [`displayName`](https://www.w3.org/TR/webauthn-3/#dictdef-currentuserdetailsoptions-displayname).
   1635     pub user: PublicKeyCredentialUserEntity<'name, 'display_name, 'id, LEN>,
   1636 }
   1637 /// [`hmac-secret`](https://fidoalliance.org/specs/fido-v2.2-rd-20230321/fido-client-to-authenticator-protocol-v2.2-rd-20230321.html#sctn-hmac-secret-extension)
   1638 /// during authentication and
   1639 /// [`hmac-secret-mc`](https://fidoalliance.org/specs/fido-v2.2-ps-20250228/fido-client-to-authenticator-protocol-v2.2-ps-20250228.html#sctn-hmac-secret-make-cred-extension)
   1640 /// during registration.
   1641 ///
   1642 /// `REG` iff `hmac-secret-mc`.
   1643 enum HmacSecretGet<const REG: bool> {
   1644     /// No `hmac-secret` response.
   1645     None,
   1646     /// One encrypted `hmac-secret`.
   1647     One,
   1648     /// Two encrypted `hmac-secret`s.
   1649     Two,
   1650 }
   1651 /// Error returned by [`HmacSecretGet::from_cbor`]
   1652 enum HmacSecretGetErr {
   1653     /// Error related to the length of the CBOR input.
   1654     Len,
   1655     /// Error related to the type of the CBOR key.
   1656     Type,
   1657     /// Error related to the value of the CBOR value.
   1658     Value,
   1659 }
   1660 impl<const REG: bool> FromCbor<'_> for HmacSecretGet<REG> {
   1661     type Err = HmacSecretGetErr;
   1662     fn from_cbor(cbor: &[u8]) -> Result<CborSuccess<'_, Self>, Self::Err> {
   1663         /// AES block size.
   1664         const AES_BLOCK_SIZE: usize = 16;
   1665         /// HMAC-SHA-256 output length.
   1666         const HMAC_SHA_256_LEN: usize = 32;
   1667         /// Length of two HMAC-SHA-256 outputs concatenated together.
   1668         const TWO_HMAC_SHA_256_LEN: usize = HMAC_SHA_256_LEN << 1;
   1669         // We need the smallest multiple of `AES_BLOCK_SIZE` that
   1670         // is strictly greater than `HMAC_SHA_256_LEN`.
   1671         /// AES-256 output length on a 32-byte input.
   1672         #[expect(
   1673             clippy::integer_division_remainder_used,
   1674             reason = "doesn't need to be constant time"
   1675         )]
   1676         const ONE_SECRET_LEN: usize =
   1677             HMAC_SHA_256_LEN + (AES_BLOCK_SIZE - (HMAC_SHA_256_LEN % AES_BLOCK_SIZE));
   1678         // We need the smallest multiple of `AES_BLOCK_SIZE` that
   1679         // is strictly greater than `TWO_HMAC_SHA_256_LEN`.
   1680         /// AES-256 output length on a 64-byte input.
   1681         #[expect(
   1682             clippy::integer_division_remainder_used,
   1683             reason = "doesn't need to be constant time"
   1684         )]
   1685         const TWO_SECRET_LEN: usize =
   1686             TWO_HMAC_SHA_256_LEN + (AES_BLOCK_SIZE - (TWO_HMAC_SHA_256_LEN % AES_BLOCK_SIZE));
   1687         /// `hmac-secret-mc`.
   1688         ///
   1689         /// This is the key iff `REG`.
   1690         const KEY: [u8; 15] = [
   1691             cbor::TEXT_14,
   1692             b'h',
   1693             b'm',
   1694             b'a',
   1695             b'c',
   1696             b'-',
   1697             b's',
   1698             b'e',
   1699             b'c',
   1700             b'r',
   1701             b'e',
   1702             b't',
   1703             b'-',
   1704             b'm',
   1705             b'c',
   1706         ];
   1707         /// Helper that unifies `HmacSecretGet`.
   1708         enum CborVal<'a> {
   1709             /// Extension does not exist with remaining payload
   1710             Success,
   1711             /// Extension exists with remaining payload.
   1712             Continue(&'a [u8]),
   1713         }
   1714         if REG {
   1715             cbor.split_at_checked(KEY.len()).map_or(
   1716                 Ok(CborVal::Success),
   1717                 |(key, key_rem)| {
   1718                     if key == KEY {
   1719                         Ok(CborVal::Continue(key_rem))
   1720                     } else {
   1721                         Ok(CborVal::Success)
   1722                     }
   1723                 }
   1724             )
   1725         } else {
   1726             cbor.split_at_checked(cbor::HMAC_SECRET.len()).map_or(
   1727                 Ok(CborVal::Success),
   1728                 |(key, key_rem)| {
   1729                     if key == cbor::HMAC_SECRET {
   1730                         Ok(CborVal::Continue(key_rem))
   1731                     } else {
   1732                         Ok(CborVal::Success)
   1733                     }
   1734                 }
   1735             )
   1736         }.and_then(|cbor_val| {
   1737             match cbor_val {
   1738                 CborVal::Success => Ok(CborSuccess { value: Self::None, remaining: cbor, }),
   1739                 CborVal::Continue(key_rem) => {
   1740                     key_rem
   1741                         .split_first()
   1742                         .ok_or(HmacSecretGetErr::Len)
   1743                         .and_then(|(bytes, bytes_rem)| {
   1744                             if *bytes == cbor::BYTES_INFO_24 {
   1745                                 bytes_rem
   1746                                     .split_first()
   1747                                     .ok_or(HmacSecretGetErr::Len)
   1748                                     .and_then(|(&len, len_rem)| {
   1749                                         len_rem.split_at_checked(usize::from(len)).ok_or(HmacSecretGetErr::Len).and_then(|(_, remaining)| {
   1750                                             match usize::from(len) {
   1751                                                 ONE_SECRET_LEN => {
   1752                                                     Ok(CborSuccess {
   1753                                                         value: Self::One,
   1754                                                         remaining,
   1755                                                     })
   1756                                                 }
   1757                                                 TWO_SECRET_LEN => {
   1758                                                     Ok(CborSuccess {
   1759                                                         value: Self::Two,
   1760                                                         remaining,
   1761                                                     })
   1762                                                 }
   1763                                                 _ => Err(HmacSecretGetErr::Value),
   1764                                             }
   1765                                         })
   1766                                     })
   1767                             } else {
   1768                                 Err(HmacSecretGetErr::Type)
   1769                             }
   1770                         })
   1771                 }
   1772             }
   1773         })
   1774     }
   1775 }
   1776 #[cfg(test)]
   1777 mod tests {
   1778     use super::{CollectedClientDataErr, ClientDataJsonParser, LimitedVerificationParser};
   1779     #[test]
   1780     fn parse_string() {
   1781         assert!(LimitedVerificationParser::<true>::parse_string(br#"abc""#)
   1782             .map_or(false, |tup| { tup.0 == "abc" && tup.1 == br#""# }));
   1783         assert!(LimitedVerificationParser::<false>::parse_string(br#"abc"23"#)
   1784             .map_or(false, |tup| { tup.0 == "abc" && tup.1 == br#"23"# }));
   1785         assert!(LimitedVerificationParser::<true>::parse_string(br#"ab\"c"23"#)
   1786             .map_or(false, |tup| { tup.0 == r#"ab"c"# && tup.1 == br#"23"# }));
   1787         assert!(LimitedVerificationParser::<false>::parse_string(br#"ab\\c"23"#)
   1788             .map_or(false, |tup| { tup.0 == r#"ab\c"# && tup.1 == br#"23"# }));
   1789         assert!(LimitedVerificationParser::<true>::parse_string(br#"ab\u001fc"23"#)
   1790             .map_or(false, |tup| { tup.0 == "ab\u{001f}c" && tup.1 == br#"23"# }));
   1791         assert!(LimitedVerificationParser::<false>::parse_string(br#"ab\u000dc"23"#)
   1792             .map_or(false, |tup| { tup.0 == "ab\u{000d}c" && tup.1 == br#"23"# }));
   1793         assert!(
   1794             LimitedVerificationParser::<true>::parse_string(b"\\\\\\\\\\\\a\\\\\\\\a\\\\\"").map_or(false, |tup| {
   1795                 tup.0 == "\\\\\\a\\\\a\\" && tup.1.is_empty()
   1796             })
   1797         );
   1798         assert!(
   1799             LimitedVerificationParser::<false>::parse_string(b"\\\\\\\\\\a\\\\\\\\a\\\\\"").map_or_else(
   1800                 |e| matches!(e, CollectedClientDataErr::InvalidEscapedString),
   1801                 |_| false
   1802             )
   1803         );
   1804         assert!(LimitedVerificationParser::<true>::parse_string(br#"ab\u0020c"23"#).map_or_else(
   1805             |err| matches!(err, CollectedClientDataErr::InvalidEscapedString),
   1806             |_| false
   1807         ));
   1808         assert!(LimitedVerificationParser::<false>::parse_string(br#"ab\ac"23"#).map_or_else(
   1809             |err| matches!(err, CollectedClientDataErr::InvalidEscapedString),
   1810             |_| false
   1811         ));
   1812         assert!(LimitedVerificationParser::<true>::parse_string(br#"ab\""#).map_or_else(
   1813             |err| matches!(err, CollectedClientDataErr::InvalidObject),
   1814             |_| false
   1815         ));
   1816         assert!(LimitedVerificationParser::<false>::parse_string(br#"ab\u001Fc"23"#).map_or_else(
   1817             |err| matches!(err, CollectedClientDataErr::InvalidEscapedString),
   1818             |_| false
   1819         ));
   1820         assert!(LimitedVerificationParser::<true>::parse_string([0, b'"'].as_slice()).map_or_else(
   1821             |err| matches!(err, CollectedClientDataErr::InvalidEscapedString),
   1822             |_| false
   1823         ));
   1824         assert!(LimitedVerificationParser::<false>::parse_string([b'a', 255, b'"'].as_slice())
   1825             .map_or_else(|err| matches!(err, CollectedClientDataErr::Utf8(_)), |_| false));
   1826         assert!(LimitedVerificationParser::<true>::parse_string([b'a', b'"', 255].as_slice()).is_ok());
   1827         assert!(
   1828             LimitedVerificationParser::<false>::parse_string(br#"""#).map_or(false, |tup| tup.0.is_empty() && tup.1.is_empty())
   1829         );
   1830     }
   1831     #[test]
   1832     fn c_data_json() {
   1833         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":false}"#.as_slice()).map_or(false, |val| val.challenge.0 == 0 && val.origin.0 == "https://example.com" && !val.cross_origin && val.top_origin.is_none()));
   1834         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":false,{}}"#.as_slice()).map_or(false, |val| val.challenge.0 == 0 && val.origin.0 == "https://example.com" && !val.cross_origin && val.top_origin.is_none()));
   1835         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":true}"#.as_slice()).map_or(false, |val| val.challenge.0 == 0 && val.origin.0 == "https://example.com" && val.cross_origin && val.top_origin.is_none()));
   1836         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":true,"topOrigin":"bob"}"#.as_slice()).map_or(false, |val| val.challenge.0 == 0 && val.origin.0 == "https://example.com" && val.cross_origin && val.top_origin.map_or(false, |v| v == "bob")));
   1837         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":true,"topOrigin":"bob",a}"#.as_slice()).map_or(false, |val| val.challenge.0 == 0 && val.origin.0 == "https://example.com" && val.cross_origin && val.top_origin.map_or(false, |v| v == "bob")));
   1838         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":true,"topOrigin":"bob"a}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::InvalidObject), |_| false));
   1839         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":false,"topOrigin":""}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::TopOriginWithoutCrossOrigin), |_| false));
   1840         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":false,"topOrigin":""}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::Challenge), |_| false));
   1841         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"","crossOrigin":false}"#.as_slice()).map_or(false, |val| val.challenge.0 == 0 && val.origin.0.is_empty() && !val.cross_origin && val.top_origin.is_none()));
   1842         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.get","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":false}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::Type), |_| false));
   1843         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.create", "challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":false}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::ChallengeKey), |_| false));
   1844         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAAA","crossOrigin":false}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::OriginKey), |_| false));
   1845         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://exampl\\e.com","crossOrigin":false}"#.as_slice()).map_or(false, |val| val.challenge.0 == 0 && val.origin.0 == "https://exampl\\e.com" && !val.cross_origin && val.top_origin.is_none()));
   1846         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://exampl\"e.com","crossOrigin":false}"#.as_slice()).map_or(false, |val| val.challenge.0 == 0 && val.origin.0 == "https://exampl\"e.com" && !val.cross_origin && val.top_origin.is_none()));
   1847         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://exampl\u0013e.com","crossOrigin":false}"#.as_slice()).map_or(false, |val| val.challenge.0 == 0 && val.origin.0 == "https://exampl\u{0013}e.com" && !val.cross_origin && val.top_origin.is_none()));
   1848         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://exampl\3e.com","crossOrigin":false}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::InvalidEscapedString), |_| false));
   1849         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://exampl\e.com","crossOrigin":false}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::InvalidEscapedString), |_| false));
   1850         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://exampl\u0020.com","crossOrigin":false}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::InvalidEscapedString), |_| false));
   1851         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://exampl\u000A.com","crossOrigin":false}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::InvalidEscapedString), |_| false));
   1852         assert!(LimitedVerificationParser::<true>::parse([].as_slice())
   1853             .map_or_else(|e| matches!(e, CollectedClientDataErr::Len), |_| false));
   1854         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"abc","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":false}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::InvalidStart), |_| false));
   1855         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":false"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::InvalidObject), |_| false));
   1856         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAAA","crossOrigin":false,"origin":"example.com"}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::OriginKey), |_| false));
   1857         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","topOrigin":"bob","crossOrigin":true}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::CrossOriginKey), |_| false));
   1858         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":"abc"}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::CrossOrigin), |_| false));
   1859         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":true"a}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::InvalidObject), |_| false));
   1860         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":true","topOrigin":"https://abc.com"a}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::InvalidObject), |_| false));
   1861         assert!(LimitedVerificationParser::<false>::parse(br#"{"type":"webauthn.get","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":false}"#.as_slice()).map_or(false, |val| val.challenge.0 == 0 && val.origin.0 == "https://example.com" && !val.cross_origin && val.top_origin.is_none()));
   1862         assert!(LimitedVerificationParser::<false>::parse(b"{\"type\":\"webauthn.get\",\"challenge\":\"AAAAAAAAAAAAAAAAAAAAAA\",\"origin\":\"https://example.com\",\"crossOrigin\":false,\xff}".as_slice()).map_or(false, |val| val.challenge.0 == 0 && val.origin.0 == "https://example.com" && !val.cross_origin && val.top_origin.is_none()));
   1863         assert!(LimitedVerificationParser::<false>::parse(br#"{"type":"webauthn.get","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":true}"#.as_slice()).map_or(false, |val| val.challenge.0 == 0 && val.origin.0 == "https://example.com" && val.cross_origin && val.top_origin.is_none()));
   1864         assert!(LimitedVerificationParser::<false>::parse(br#"{"type":"webauthn.get","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":true,"topOrigin":"bob"}"#.as_slice()).map_or(false, |val| val.challenge.0 == 0 && val.origin.0 == "https://example.com" && val.cross_origin && val.top_origin.map_or(false, |v| v == "bob")));
   1865         assert!(LimitedVerificationParser::<false>::parse(br#"{"type":"webauthn.get","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":false,"topOrigin":""}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::TopOriginWithoutCrossOrigin), |_| false));
   1866         assert!(LimitedVerificationParser::<false>::parse(br#"{"type":"webauthn.get","challenge":"AAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":false,"topOrigin":""}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::Challenge), |_| false));
   1867         assert!(LimitedVerificationParser::<false>::parse(br#"{"type":"webauthn.get","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"","crossOrigin":false}"#.as_slice()).map_or(false, |val| val.challenge.0 == 0 && val.origin.0.is_empty() && !val.cross_origin && val.top_origin.is_none()));
   1868         assert!(LimitedVerificationParser::<false>::parse(br#"{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":false}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::Type), |_| false));
   1869         assert!(LimitedVerificationParser::<false>::parse(br#"{"type":"webauthn.get", "challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":false}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::ChallengeKey), |_| false));
   1870         assert!(LimitedVerificationParser::<false>::parse(
   1871             br#"{"type":"webauthn.get","challenge":"AAAAAAAAAAAAAAAAAAAAAA","crossOrigin":false}"#
   1872                 .as_slice()
   1873         )
   1874         .map_or_else(|e| matches!(e, CollectedClientDataErr::OriginKey), |_| false));
   1875         assert!(LimitedVerificationParser::<false>::parse(br#"{"type":"webauthn.get","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://exampl\\e.com","crossOrigin":false}"#.as_slice()).map_or(false, |val| val.challenge.0 == 0 && val.origin.0 == "https://exampl\\e.com" && !val.cross_origin && val.top_origin.is_none()));
   1876         assert!(LimitedVerificationParser::<false>::parse(br#"{"type":"webauthn.get","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://exampl\"e.com","crossOrigin":false}"#.as_slice()).map_or(false, |val| val.challenge.0 == 0 && val.origin.0 == "https://exampl\"e.com" && !val.cross_origin && val.top_origin.is_none()));
   1877         assert!(LimitedVerificationParser::<false>::parse(br#"{"type":"webauthn.get","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://exampl\u0013e.com","crossOrigin":false}"#.as_slice()).map_or(false, |val| val.challenge.0 == 0 && val.origin.0 == "https://exampl\u{0013}e.com" && !val.cross_origin && val.top_origin.is_none()));
   1878         assert!(LimitedVerificationParser::<false>::parse(br#"{"type":"webauthn.get","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://exampl\3e.com","crossOrigin":false}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::InvalidEscapedString), |_| false));
   1879         assert!(LimitedVerificationParser::<false>::parse(br#"{"type":"webauthn.get","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://exampl\e.com","crossOrigin":false}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::InvalidEscapedString), |_| false));
   1880         assert!(LimitedVerificationParser::<false>::parse(br#"{"type":"webauthn.get","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://exampl\u0020.com","crossOrigin":false}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::InvalidEscapedString), |_| false));
   1881         assert!(LimitedVerificationParser::<false>::parse(br#"{"type":"webauthn.get","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://exampl\u000A.com","crossOrigin":false}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::InvalidEscapedString), |_| false));
   1882         assert!(LimitedVerificationParser::<false>::parse([].as_slice())
   1883             .map_or_else(|e| matches!(e, CollectedClientDataErr::Len), |_| false));
   1884         assert!(LimitedVerificationParser::<false>::parse(br#"{"type":"abc","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":false}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::InvalidStart), |_| false));
   1885         assert!(LimitedVerificationParser::<false>::parse(br#"{"type":"webauthn.get","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":false"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::InvalidObject), |_| false));
   1886         assert!(LimitedVerificationParser::<false>::parse(br#"{"type":"webauthn.get","challenge":"AAAAAAAAAAAAAAAAAAAAAA","crossOrigin":false,"origin":"example.com"}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::OriginKey), |_| false));
   1887         assert!(LimitedVerificationParser::<false>::parse(br#"{"type":"webauthn.get","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","topOrigin":"bob","crossOrigin":true}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::CrossOriginKey), |_| false));
   1888         assert!(LimitedVerificationParser::<false>::parse(br#"{"type":"webauthn.get","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":"abc"}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::CrossOrigin), |_| false));
   1889         assert!(LimitedVerificationParser::<false>::parse(br#"{"type":"webauthn.get","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":true"a}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::InvalidObject), |_| false));
   1890         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":true,"topOrigin":"https://example.com"}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::TopOriginSameAsOrigin), |_| false));
   1891         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.create","challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":false,"foo":true}"#.as_slice()).map_or(false, |val| val.challenge.0 == 0 && val.origin.0 == "https://example.com" && !val.cross_origin && val.top_origin.is_none()));
   1892         assert!(LimitedVerificationParser::<false>::parse(br#"{"type":"webauthn.get","challengE":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossOrigin":false,"foo":true}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::ChallengeKey), |_| false));
   1893         assert!(LimitedVerificationParser::<true>::parse(br#"{"type":"webauthn.create"challenge":"AAAAAAAAAAAAAAAAAAAAAA","origin":"https://example.com","crossorigin":false,"foo":true}"#.as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::ChallengeKey), |_| false));
   1894     }
   1895     #[test]
   1896     fn c_data_challenge() {
   1897         assert!(LimitedVerificationParser::<false>::get_sent_challenge([].as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::Len), |_| false));
   1898         assert!(LimitedVerificationParser::<true>::get_sent_challenge([].as_slice()).map_or_else(|e| matches!(e, CollectedClientDataErr::Len), |_| false));
   1899         assert!(LimitedVerificationParser::<true>::get_sent_challenge(b"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABBBBBBBBBBBBBBBBBBBBBB").map_or_else(|e| matches!(e, CollectedClientDataErr::Challenge), |_| false));
   1900         assert!(LimitedVerificationParser::<false>::get_sent_challenge(b"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABBBBBBBBBBBBBBBBBBBBBB").map_or_else(|e| matches!(e, CollectedClientDataErr::Challenge), |_| false));
   1901         assert!(LimitedVerificationParser::<true>::get_sent_challenge(b"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA".as_slice()).map_or(false, |c| c.0 == 0));
   1902         assert!(LimitedVerificationParser::<false>::get_sent_challenge(b"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA".as_slice()).map_or(false, |c| c.0 == 0));
   1903     }
   1904 }
	webauthn_rp WebAuthn Level 3 RP library.
	git clone https://git.philomathiclife.com/repos/webauthn_rp
	Log \| Files \| Refs \| README