ctap2.3: add wire types for FIDO_2_3, smart-card transport, enableLongTouchForReset

Author: 0x0ece

Cargo.toml

@@ -34,6 +34,10 @@ arbitrary = ["dep:arbitrary", "std"]
 get-info-full = []
 # enables support for implementing the large-blobs extension, see src/sizes.rs
 large-blobs = []
+# Bumps `MAX_PACKED_SIG_LENGTH` and the per-cert size in `x5c` so packed
+# attestation can carry an ML-DSA-44 (CTAP 2.3 alg -50) signature (2420 B)
+# alongside the now-larger AUTHENTICATOR_DATA_LENGTH for ML-DSA pubkeys.
+mldsa44 = []
 third-party-payment = []
 
 log-all = []

src/ctap2.rs

@@ -308,9 +308,9 @@ pub struct NoneAttestationStatement {}
 #[derive(Clone, Debug, Eq, PartialEq, Serialize)]
 pub struct PackedAttestationStatement {
     pub alg: i32,
-    pub sig: Bytes<ASN1_SIGNATURE_LENGTH>,
+    pub sig: Bytes<MAX_PACKED_SIG_LENGTH>,
     #[serde(skip_serializing_if = "Option::is_none")]
-    pub x5c: Option<Vec<Bytes<1024>, 1>>,
+    pub x5c: Option<Vec<Bytes<MAX_X5C_CERT_LENGTH>, 1>>,
 }
 
 #[derive(Clone, Debug, Default, Eq, PartialEq)]

src/ctap2/authenticator_config.rs

@@ -17,6 +17,7 @@ pub enum Subcommand {
     EnableEnterpriseAttestation = 0x01,
     ToggleAlwaysUv = 0x02,
     SetMinPINLength = 0x03,
+    EnableLongTouchForReset = 0x04,
     VendorPrototype = 0xff,
 }
 
@@ -63,6 +64,7 @@ mod tests {
             (Subcommand::EnableEnterpriseAttestation, 0x01),
             (Subcommand::ToggleAlwaysUv, 0x02),
             (Subcommand::SetMinPINLength, 0x03),
+            (Subcommand::EnableLongTouchForReset, 0x04),
             (Subcommand::VendorPrototype, 0xff),
         ] {
             assert_tokens(&sub, &[Token::U8(byte)]);

src/ctap2/get_assertion.rs

@@ -133,7 +133,7 @@ pub struct Request<'a> {
 pub struct Response {
     pub credential: PublicKeyCredentialDescriptor,
     pub auth_data: Bytes<AUTHENTICATOR_DATA_LENGTH>,
-    pub signature: Bytes<ASN1_SIGNATURE_LENGTH>,
+    pub signature: Bytes<MAX_PACKED_SIG_LENGTH>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub user: Option<PublicKeyCredentialUserEntity>,
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -156,7 +156,7 @@ pub struct Response {
 pub struct ResponseBuilder {
     pub credential: PublicKeyCredentialDescriptor,
     pub auth_data: Bytes<AUTHENTICATOR_DATA_LENGTH>,
-    pub signature: Bytes<ASN1_SIGNATURE_LENGTH>,
+    pub signature: Bytes<MAX_PACKED_SIG_LENGTH>,
 }
 
 impl ResponseBuilder {

src/ctap2/get_info.rs

@@ -10,7 +10,7 @@ pub type AuthenticatorInfo = Response;
 #[serde_indexed(offset = 1)]
 pub struct Response {
     // 0x01
-    pub versions: Vec<Version, 4>,
+    pub versions: Vec<Version, 5>,
 
     // 0x02
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -154,7 +154,7 @@ impl Default for Response {
 
 #[derive(Debug)]
 pub struct ResponseBuilder {
-    pub versions: Vec<Version, 4>,
+    pub versions: Vec<Version, 5>,
     pub aaguid: Bytes<16>,
 }
 
@@ -211,6 +211,7 @@ pub enum Version {
     Fido2_1,
     Fido2_1Pre,
     Fido2_2,
+    Fido2_3,
     U2fV2,
 }
 
@@ -219,6 +220,7 @@ impl Version {
     const FIDO_2_1: &'static str = "FIDO_2_1";
     const FIDO_2_1_PRE: &'static str = "FIDO_2_1_PRE";
     const FIDO_2_2: &'static str = "FIDO_2_2";
+    const FIDO_2_3: &'static str = "FIDO_2_3";
     const U2F_V2: &'static str = "U2F_V2";
 }
 
@@ -229,6 +231,7 @@ impl From<Version> for &str {
             Version::Fido2_1 => Version::FIDO_2_1,
             Version::Fido2_1Pre => Version::FIDO_2_1_PRE,
             Version::Fido2_2 => Version::FIDO_2_2,
+            Version::Fido2_3 => Version::FIDO_2_3,
             Version::U2fV2 => Version::U2F_V2,
         }
     }
@@ -243,6 +246,7 @@ impl TryFrom<&str> for Version {
             Self::FIDO_2_1 => Ok(Self::Fido2_1),
             Self::FIDO_2_1_PRE => Ok(Self::Fido2_1Pre),
             Self::FIDO_2_2 => Ok(Self::Fido2_2),
+            Self::FIDO_2_3 => Ok(Self::Fido2_3),
             Self::U2F_V2 => Ok(Self::U2fV2),
             _ => Err(TryFromStrError),
         }
@@ -308,18 +312,21 @@ impl TryFrom<&str> for Extension {
 #[serde(into = "&str", try_from = "&str")]
 pub enum Transport {
     Nfc,
+    SmartCard,
     Usb,
 }
 
 impl Transport {
     const NFC: &'static str = "nfc";
+    const SMART_CARD: &'static str = "smart-card";
     const USB: &'static str = "usb";
 }
 
 impl From<Transport> for &str {
     fn from(transport: Transport) -> Self {
         match transport {
             Transport::Nfc => Transport::NFC,
+            Transport::SmartCard => Transport::SMART_CARD,
             Transport::Usb => Transport::USB,
         }
     }
@@ -331,6 +338,7 @@ impl TryFrom<&str> for Transport {
     fn try_from(s: &str) -> Result<Self, Self::Error> {
         match s {
             Self::NFC => Ok(Self::Nfc),
+            Self::SMART_CARD => Ok(Self::SmartCard),
             Self::USB => Ok(Self::Usb),
             _ => Err(TryFromStrError),
         }
@@ -479,6 +487,7 @@ mod tests {
             (Version::Fido2_1, "FIDO_2_1"),
             (Version::Fido2_1Pre, "FIDO_2_1_PRE"),
             (Version::Fido2_2, "FIDO_2_2"),
+            (Version::Fido2_3, "FIDO_2_3"),
             (Version::U2fV2, "U2F_V2"),
         ];
         for (version, s) in versions {
@@ -504,7 +513,11 @@ mod tests {
 
     #[test]
     fn test_serde_transport() {
-        let transports = [(Transport::Nfc, "nfc"), (Transport::Usb, "usb")];
+        let transports = [
+            (Transport::Nfc, "nfc"),
+            (Transport::SmartCard, "smart-card"),
+            (Transport::Usb, "usb"),
+        ];
         for (transport, s) in transports {
             assert_tokens(&transport, &[Token::BorrowedStr(s)]);
         }

src/sizes.rs

@@ -1,5 +1,29 @@
+// Sized to hold ML-DSA-44 authData (header + 1312-byte raw public key
+// wrapped in a ~10-byte COSE_Key map + AAGUID + credId + extensions).
+// Pre-mldsa44 builds used 676 bytes which overflowed silently on alg=-50,
+// surfacing as `extend_from_slice` Err → CTAP `Error::Other` (0x7F).
+// Gated so non-mldsa44 builds keep the historical footprint.
+#[cfg(feature = "mldsa44")]
+pub const AUTHENTICATOR_DATA_LENGTH: usize = 2048;
+#[cfg(not(feature = "mldsa44"))]
 pub const AUTHENTICATOR_DATA_LENGTH: usize = 676;
-// pub const AUTHENTICATOR_DATA_LENGTH_BYTES: usize = 512;
+
+/// Max length of a packed-attestation signature. ECDSA over P-256 fits in
+/// `ASN1_SIGNATURE_LENGTH` (77 B). With `mldsa44`, the authenticator may
+/// sign with ML-DSA-44 whose signature is 2420 bytes, so we bump.
+#[cfg(feature = "mldsa44")]
+pub const MAX_PACKED_SIG_LENGTH: usize = 2432;
+#[cfg(not(feature = "mldsa44"))]
+pub const MAX_PACKED_SIG_LENGTH: usize = ASN1_SIGNATURE_LENGTH;
+
+/// Max length of one x5c entry (the attestation certificate carried in
+/// `PackedAttestationStatement.x5c`). Matches what trussed's
+/// `read_certificate` Reply.der fits in (`Message`); 1024 historically,
+/// 2048 with `mldsa44` so larger Message buffers don't truncate.
+#[cfg(feature = "mldsa44")]
+pub const MAX_X5C_CERT_LENGTH: usize = 2048;
+#[cfg(not(feature = "mldsa44"))]
+pub const MAX_X5C_CERT_LENGTH: usize = 1024;
 
 pub const ASN1_SIGNATURE_LENGTH: usize = 77;
 // pub const ASN1_SIGNATURE_LENGTH_BYTES: usize = 72;

src/webauthn.rs

@@ -158,9 +158,11 @@ pub enum UnknownPKCredentialParam {
 pub const ES256: i32 = -7;
 /// EdDSA
 pub const ED_DSA: i32 = -8;
+/// ML-DSA-44 (FIPS 204, NIST level 2)
+pub const ML_DSA_44: i32 = -50;
 
-pub const COUNT_KNOWN_ALGS: usize = 2;
-pub const KNOWN_ALGS: [i32; COUNT_KNOWN_ALGS] = [ES256, ED_DSA];
+pub const COUNT_KNOWN_ALGS: usize = 3;
+pub const KNOWN_ALGS: [i32; COUNT_KNOWN_ALGS] = [ES256, ED_DSA, ML_DSA_44];
 
 impl TryFrom<PublicKeyCredentialParameters> for KnownPublicKeyCredentialParameters {
     type Error = UnknownPKCredentialParam;