From d9c4c729e8fd871d787589353166dbd35c6ba0e2 Mon Sep 17 00:00:00 2001
From: Fabian Kaczmarczyck <kaczmarczyck@google.com>
Date: Mon, 27 Apr 2020 20:00:39 +0200
Subject: [PATCH] adds a feature flag for CTAP2.1, addresses comments

---
 Cargo.toml               |   1 +
 README.md                |   8 ++-
 deploy.py                |   8 +++
 run_desktop_tests.sh     |   7 +++
 src/ctap/command.rs      |  49 +++++++---------
 src/ctap/data_formats.rs | 120 +++++++++++++++++++++++++++++++++++----
 src/ctap/mod.rs          |  51 +++++++++++++----
 src/ctap/response.rs     |  90 +++++++++++++++++++++++++++--
 8 files changed, 274 insertions(+), 60 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 1d1ad6e..4c2d16c 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -25,6 +25,7 @@ std = ["cbor/std", "crypto/std", "crypto/derive_debug"]
 ram_storage = []
 verbose = ["debug_ctap"]
 with_ctap1 = ["crypto/with_ctap1"]
+with_ctap2_1 = []
 
 [dev-dependencies]
 elf2tab = "0.4.0"
diff --git a/README.md b/README.md
index fb7d1c9..8dcc761 100644
--- a/README.md
+++ b/README.md
@@ -28,9 +28,11 @@ few limitations:
 Although we tested and implemented our firmware based on the published
 [CTAP2.0 specifications](https://fidoalliance.org/specs/fido-v2.0-ps-20190130/fido-client-to-authenticator-protocol-v2.0-ps-20190130.html),
 our implementation was not reviewed nor officially tested and doesn't claim to
-be FIDO Certified. With the upcoming next version of the
-[CTAP2.1 specifications](https://fidoalliance.org/specs/fido2/fido-client-to-authenticator-protocol-v2.1-rd-20191217.html),
-we started adding features, so master is currently between version 2.0 and 2.1.
+be FIDO Certified.
+We started adding features of the upcoming next version of the
+[CTAP2.1 specifications](https://fidoalliance.org/specs/fido2/fido-client-to-authenticator-protocol-v2.1-rd-20191217.html).
+The development is currently between 2.0 and 2.1, with updates hidden behind a feature flag.
+Please add the flag `shell --ctap2-1` to the deploy command to include them.
 
 ### Cryptography
 
diff --git a/deploy.py b/deploy.py
index f519885..e9e599d 100755
--- a/deploy.py
+++ b/deploy.py
@@ -741,6 +741,14 @@ if __name__ == "__main__":
       help=("Compiles the OpenSK application without backward compatible "
             "support for U2F/CTAP1 protocol."),
   )
+  main_parser.add_argument(
+      "--ctap2-1",
+      action=RemoveConstAction,
+      const="with_ctap2_1",
+      dest="features",
+      help=("Compiles the OpenSK application with backward compatible "
+            "support for CTAP2.1 protocol."),
+  )
   main_parser.add_argument(
       "--regen-keys",
       action="store_true",
diff --git a/run_desktop_tests.sh b/run_desktop_tests.sh
index 36bde36..0613e34 100755
--- a/run_desktop_tests.sh
+++ b/run_desktop_tests.sh
@@ -30,6 +30,7 @@ cargo build --manifest-path third_party/tock/tools/sha256sum/Cargo.toml
 echo "Checking that CTAP2 builds properly..."
 cargo check --release --target=thumbv7em-none-eabi
 cargo check --release --target=thumbv7em-none-eabi --features with_ctap1
+cargo check --release --target=thumbv7em-none-eabi --features with_ctap2_1
 cargo check --release --target=thumbv7em-none-eabi --features debug_ctap
 cargo check --release --target=thumbv7em-none-eabi --features panic_console
 cargo check --release --target=thumbv7em-none-eabi --features debug_allocations
@@ -86,4 +87,10 @@ then
 
   echo "Running unit tests on the desktop (debug mode + CTAP1)..."
   cargo test --features std,with_ctap1
+
+  echo "Running unit tests on the desktop (release mode + CTAP2.1)..."
+  cargo test --release --features std,with_ctap2_1
+
+  echo "Running unit tests on the desktop (debug mode + CTAP2.1)..."
+  cargo test --features std,with_ctap2_1
 fi
diff --git a/src/ctap/command.rs b/src/ctap/command.rs
index 9ccf104..19132bc 100644
--- a/src/ctap/command.rs
+++ b/src/ctap/command.rs
@@ -23,9 +23,10 @@ use alloc::string::String;
 use alloc::vec::Vec;
 use core::convert::TryFrom;
 
-// Depending on your memory, you can use Some(n) to limit request sizes.
+// Depending on your memory, you can use Some(n) to limit request sizes in
+// MakeCredential and GetAssertion. This affects allowList and excludeList.
 // You might also want to set the max credential size in process_get_info then.
-pub const MAX_CREDENTIAL_COUNT_IN_LIST: Option<u64> = None;
+pub const MAX_CREDENTIAL_COUNT_IN_LIST: Option<usize> = None;
 
 // CTAP specification (version 20190130) section 6.1
 #[cfg_attr(any(test, feature = "debug_ctap"), derive(Debug, PartialEq))]
@@ -136,25 +137,19 @@ impl TryFrom<cbor::Value> for AuthenticatorMakeCredentialParameters {
         )?)?;
 
         let cred_param_vec = read_array(ok_or_missing(param_map.get(&cbor_unsigned!(4)))?)?;
-        let mut pub_key_cred_params = vec![];
-        for cred_param_map_value in cred_param_vec {
-            if let Ok(cred_param) = PublicKeyCredentialParameter::try_from(cred_param_map_value) {
-                pub_key_cred_params.push(cred_param);
-            }
-        }
+        let pub_key_cred_params = cred_param_vec
+            .iter()
+            .map(PublicKeyCredentialParameter::try_from)
+            .collect::<Result<Vec<PublicKeyCredentialParameter>, Ctap2StatusCode>>()?;
 
         let exclude_list = match param_map.get(&cbor_unsigned!(5)) {
             Some(entry) => {
                 let exclude_list_vec = read_array(entry)?;
-                let mut exclude_list = vec![];
-                for exclude_list_value in exclude_list_vec {
-                    if let Some(count) = MAX_CREDENTIAL_COUNT_IN_LIST {
-                        if exclude_list.len() as u64 >= count {
-                            break;
-                        }
-                    }
-                    exclude_list.push(PublicKeyCredentialDescriptor::try_from(exclude_list_value)?);
-                }
+                let exclude_list = exclude_list_vec
+                    .iter()
+                    .take(MAX_CREDENTIAL_COUNT_IN_LIST.unwrap_or(exclude_list_vec.len()))
+                    .map(PublicKeyCredentialDescriptor::try_from)
+                    .collect::<Result<Vec<PublicKeyCredentialDescriptor>, Ctap2StatusCode>>()?;
                 Some(exclude_list)
             }
             None => None,
@@ -222,15 +217,11 @@ impl TryFrom<cbor::Value> for AuthenticatorGetAssertionParameters {
         let allow_list = match param_map.get(&cbor_unsigned!(3)) {
             Some(entry) => {
                 let allow_list_vec = read_array(entry)?;
-                let mut allow_list = vec![];
-                for allow_list_value in allow_list_vec {
-                    if let Some(count) = MAX_CREDENTIAL_COUNT_IN_LIST {
-                        if allow_list.len() as u64 >= count {
-                            break;
-                        }
-                    }
-                    allow_list.push(PublicKeyCredentialDescriptor::try_from(allow_list_value)?);
-                }
+                let allow_list = allow_list_vec
+                    .iter()
+                    .take(MAX_CREDENTIAL_COUNT_IN_LIST.unwrap_or(allow_list_vec.len()))
+                    .map(PublicKeyCredentialDescriptor::try_from)
+                    .collect::<Result<Vec<PublicKeyCredentialDescriptor>, Ctap2StatusCode>>()?;
                 Some(allow_list)
             }
             None => None,
@@ -330,7 +321,7 @@ mod test {
         AuthenticatorTransport, PublicKeyCredentialRpEntity, PublicKeyCredentialType,
         PublicKeyCredentialUserEntity,
     };
-    use super::super::CREDENTIAL_PARAMETER;
+    use super::super::ES256_CRED_PARAM;
     use super::*;
     use alloc::collections::BTreeMap;
 
@@ -349,7 +340,7 @@ mod test {
                 "displayName" => "bar",
                 "icon" => "example.com/foo/icon.png",
             },
-            4 => cbor_array![CREDENTIAL_PARAMETER],
+            4 => cbor_array![ES256_CRED_PARAM],
             5 => cbor_array![],
             8 => vec![0x12, 0x34],
             9 => 1,
@@ -380,7 +371,7 @@ mod test {
             client_data_hash,
             rp,
             user,
-            pub_key_cred_params: vec![CREDENTIAL_PARAMETER],
+            pub_key_cred_params: vec![ES256_CRED_PARAM],
             exclude_list: Some(vec![]),
             extensions: None,
             options,
diff --git a/src/ctap/data_formats.rs b/src/ctap/data_formats.rs
index a4bbe39..4f7e31c 100644
--- a/src/ctap/data_formats.rs
+++ b/src/ctap/data_formats.rs
@@ -19,6 +19,7 @@ use alloc::vec::Vec;
 use core::convert::TryFrom;
 use crypto::{ecdh, ecdsa};
 
+// https://www.w3.org/TR/webauthn/#dictdef-publickeycredentialrpentity
 #[cfg_attr(any(test, feature = "debug_ctap"), derive(Debug, PartialEq))]
 pub struct PublicKeyCredentialRpEntity {
     pub rp_id: String,
@@ -48,6 +49,7 @@ impl TryFrom<&cbor::Value> for PublicKeyCredentialRpEntity {
     }
 }
 
+// https://www.w3.org/TR/webauthn/#dictdef-publickeycredentialuserentity
 #[cfg_attr(any(test, feature = "debug_ctap"), derive(Debug, PartialEq))]
 pub struct PublicKeyCredentialUserEntity {
     pub user_id: Vec<u8>,
@@ -94,16 +96,22 @@ impl From<PublicKeyCredentialUserEntity> for cbor::Value {
     }
 }
 
+// https://www.w3.org/TR/webauthn/#enumdef-publickeycredentialtype
 #[derive(Clone, PartialEq)]
 #[cfg_attr(any(test, feature = "debug_ctap"), derive(Debug))]
 pub enum PublicKeyCredentialType {
     PublicKey,
+    // This is the default for all strings not covered above.
+    // Unknown types should be ignored, instead of returning errors.
+    Unknown,
 }
 
 impl From<PublicKeyCredentialType> for cbor::Value {
     fn from(cred_type: PublicKeyCredentialType) -> Self {
         match cred_type {
             PublicKeyCredentialType::PublicKey => "public-key",
+            // We should never create this credential type.
+            PublicKeyCredentialType::Unknown => unreachable!(),
         }
         .into()
     }
@@ -116,11 +124,12 @@ impl TryFrom<&cbor::Value> for PublicKeyCredentialType {
         let cred_type_string = read_text_string(cbor_value)?;
         match &cred_type_string[..] {
             "public-key" => Ok(PublicKeyCredentialType::PublicKey),
-            _ => Err(Ctap2StatusCode::CTAP2_ERR_UNSUPPORTED_ALGORITHM),
+            _ => Ok(PublicKeyCredentialType::Unknown),
         }
     }
 }
 
+// https://www.w3.org/TR/webauthn/#dictdef-publickeycredentialparameters
 #[derive(PartialEq)]
 #[cfg_attr(any(test, feature = "debug_ctap"), derive(Debug))]
 pub struct PublicKeyCredentialParameter {
@@ -151,6 +160,7 @@ impl From<PublicKeyCredentialParameter> for cbor::Value {
     }
 }
 
+// https://www.w3.org/TR/webauthn/#enumdef-authenticatortransport
 #[cfg_attr(any(test, feature = "debug_ctap"), derive(Debug, PartialEq))]
 pub enum AuthenticatorTransport {
     Usb,
@@ -186,6 +196,7 @@ impl TryFrom<&cbor::Value> for AuthenticatorTransport {
     }
 }
 
+// https://www.w3.org/TR/webauthn/#dictdef-publickeycredentialdescriptor
 #[cfg_attr(any(test, feature = "debug_ctap"), derive(Debug, PartialEq))]
 pub struct PublicKeyCredentialDescriptor {
     pub key_type: PublicKeyCredentialType,
@@ -205,10 +216,11 @@ impl TryFrom<&cbor::Value> for PublicKeyCredentialDescriptor {
         let transports = match cred_desc_map.get(&cbor_text!("transports")) {
             Some(exclude_entry) => {
                 let transport_vec = read_array(exclude_entry)?;
-                let mut transports = vec![];
-                for transport_value in transport_vec {
-                    transports.push(AuthenticatorTransport::try_from(transport_value)?);
-                }
+                let transports = transport_vec
+                    .iter()
+                    .map(AuthenticatorTransport::try_from)
+                    .collect::<Result<Vec<AuthenticatorTransport>, Ctap2StatusCode>>(
+                )?;
                 Some(transports)
             }
             None => None,
@@ -379,6 +391,7 @@ impl TryFrom<&cbor::Value> for GetAssertionOptions {
     }
 }
 
+// https://www.w3.org/TR/webauthn/#packed-attestation
 #[cfg_attr(test, derive(PartialEq))]
 #[cfg_attr(any(test, feature = "debug_ctap"), derive(Debug))]
 pub struct PackedAttestationStatement {
@@ -403,6 +416,9 @@ impl From<PackedAttestationStatement> for cbor::Value {
 #[cfg_attr(any(test, feature = "debug_ctap"), derive(Debug))]
 pub enum SignatureAlgorithm {
     ES256 = ecdsa::PubKey::ES256_ALGORITHM as isize,
+    // This is the default for all numbers not covered above.
+    // Unknown types should be ignored, instead of returning errors.
+    Unknown = 0,
 }
 
 impl TryFrom<&cbor::Value> for SignatureAlgorithm {
@@ -411,11 +427,12 @@ impl TryFrom<&cbor::Value> for SignatureAlgorithm {
     fn try_from(cbor_value: &cbor::Value) -> Result<Self, Ctap2StatusCode> {
         match read_integer(cbor_value)? {
             ecdsa::PubKey::ES256_ALGORITHM => Ok(SignatureAlgorithm::ES256),
-            _ => Err(Ctap2StatusCode::CTAP2_ERR_UNSUPPORTED_ALGORITHM),
+            _ => Ok(SignatureAlgorithm::Unknown),
         }
     }
 }
 
+// https://www.w3.org/TR/webauthn/#public-key-credential-source
 #[derive(Clone)]
 #[cfg_attr(test, derive(PartialEq))]
 #[cfg_attr(any(test, feature = "debug_ctap"), derive(Debug))]
@@ -679,6 +696,7 @@ mod test {
     use self::Ctap2StatusCode::CTAP2_ERR_CBOR_UNEXPECTED_TYPE;
     use super::*;
     use alloc::collections::BTreeMap;
+    use crypto::rng256::{Rng256, ThreadRng256};
 
     #[test]
     fn test_read_unsigned() {
@@ -990,6 +1008,26 @@ mod test {
         assert_eq!(credential_type, Ok(expected_credential_type));
         let created_cbor: cbor::Value = credential_type.unwrap().into();
         assert_eq!(created_cbor, cbor_credential_type);
+
+        let cbor_unknown_type = cbor_text!("unknown-type");
+        let unknown_type = PublicKeyCredentialType::try_from(&cbor_unknown_type);
+        let expected_unknown_type = PublicKeyCredentialType::Unknown;
+        assert_eq!(unknown_type, Ok(expected_unknown_type));
+    }
+
+    #[test]
+    fn test_from_into_signature_algorithm() {
+        let cbor_signature_algorithm = cbor_int!(ecdsa::PubKey::ES256_ALGORITHM);
+        let signature_algorithm = SignatureAlgorithm::try_from(&cbor_signature_algorithm);
+        let expected_signature_algorithm = SignatureAlgorithm::ES256;
+        assert_eq!(signature_algorithm, Ok(expected_signature_algorithm));
+        let created_cbor: cbor::Value = cbor_int!(signature_algorithm.unwrap() as i64);
+        assert_eq!(created_cbor, cbor_signature_algorithm);
+
+        let cbor_unknown_algorithm = cbor_int!(-1);
+        let unknown_algorithm = SignatureAlgorithm::try_from(&cbor_unknown_algorithm);
+        let expected_unknown_algorithm = SignatureAlgorithm::Unknown;
+        assert_eq!(unknown_algorithm, Ok(expected_unknown_algorithm));
     }
 
     #[test]
@@ -1006,6 +1044,23 @@ mod test {
         assert_eq!(created_cbor, cbor_authenticator_transport);
     }
 
+    #[test]
+    fn test_from_into_public_key_credential_parameter() {
+        let cbor_credential_parameter = cbor_map! {
+            "type" => "public-key",
+            "alg" => ecdsa::PubKey::ES256_ALGORITHM,
+        };
+        let credential_parameter =
+            PublicKeyCredentialParameter::try_from(&cbor_credential_parameter);
+        let expected_credential_parameter = PublicKeyCredentialParameter {
+            cred_type: PublicKeyCredentialType::PublicKey,
+            alg: SignatureAlgorithm::ES256,
+        };
+        assert_eq!(credential_parameter, Ok(expected_credential_parameter));
+        let created_cbor: cbor::Value = credential_parameter.unwrap().into();
+        assert_eq!(created_cbor, cbor_credential_parameter);
+    }
+
     #[test]
     fn test_from_into_public_key_credential_descriptor() {
         let cbor_credential_descriptor = cbor_map! {
@@ -1026,7 +1081,7 @@ mod test {
     }
 
     #[test]
-    fn test_from_extensions() {
+    fn test_from_into_extensions() {
         let cbor_extensions = cbor_map! {
             "the_answer" => 42,
         };
@@ -1036,6 +1091,53 @@ mod test {
             .0
             .insert("the_answer".to_string(), cbor_int!(42));
         assert_eq!(extensions, Ok(expected_extensions));
+        let created_cbor: cbor::Value = extensions.unwrap().into();
+        assert_eq!(created_cbor, cbor_extensions);
+    }
+
+    #[test]
+    fn test_from_into_get_assertion_hmac_secret_output() {
+        let cbor_output = cbor_bytes![vec![0xC0; 32]];
+        let output = GetAssertionHmacSecretOutput::try_from(&cbor_output);
+        let expected_output = GetAssertionHmacSecretOutput(vec![0xC0; 32]);
+        assert_eq!(output, Ok(expected_output));
+        let created_cbor: cbor::Value = output.unwrap().into();
+        assert_eq!(created_cbor, cbor_output);
+    }
+
+    #[test]
+    fn test_hmac_secret_extension() {
+        let cbor_extensions = cbor_map! {
+            "hmac-secret" => true,
+        };
+        let extensions = Extensions::try_from(&cbor_extensions).unwrap();
+        assert!(extensions.has_make_credential_hmac_secret().unwrap());
+
+        let cbor_extensions = cbor_map! {
+            "hmac-secret" => false,
+        };
+        let extensions = Extensions::try_from(&cbor_extensions).unwrap();
+        assert!(!extensions.has_make_credential_hmac_secret().unwrap());
+
+        let mut rng = ThreadRng256 {};
+        let sk = crypto::ecdh::SecKey::gensk(&mut rng);
+        let pk = sk.genpk();
+        let cose_key = CoseKey::from(pk.clone());
+        let cbor_extensions = cbor_map! {
+            "hmac-secret" => cbor_map! {
+                1 => cbor::Value::Map(cose_key.0.clone()),
+                2 => vec![0x02; 32],
+                3 => vec![0x03; 32],
+            },
+        };
+        let extensions = Extensions::try_from(&cbor_extensions).unwrap();
+        let get_assertion_input = extensions.get_assertion_hmac_secret();
+        let expected_input = GetAssertionHmacSecretInput {
+            key_agreement: cose_key,
+            salt_enc: vec![0x02; 32],
+            salt_auth: vec![0x03; 32],
+        };
+        assert_eq!(get_assertion_input, Some(Ok(expected_input)));
     }
 
     #[test]
@@ -1087,8 +1189,6 @@ mod test {
 
     #[test]
     fn test_from_into_cose_key() {
-        use crypto::rng256::ThreadRng256;
-
         let mut rng = ThreadRng256 {};
         let sk = crypto::ecdh::SecKey::gensk(&mut rng);
         let pk = sk.genpk();
@@ -1109,8 +1209,6 @@ mod test {
 
     #[test]
     fn test_credential_source_cbor_round_trip() {
-        use crypto::rng256::{Rng256, ThreadRng256};
-
         let mut rng = ThreadRng256 {};
         let credential = PublicKeyCredentialSource {
             key_type: PublicKeyCredentialType::PublicKey,
diff --git a/src/ctap/mod.rs b/src/ctap/mod.rs
index 7624435..24039ad 100644
--- a/src/ctap/mod.rs
+++ b/src/ctap/mod.rs
@@ -23,15 +23,18 @@ pub mod status_code;
 mod storage;
 mod timed_permission;
 
+#[cfg(feature = "with_ctap2_1")]
+use self::command::MAX_CREDENTIAL_COUNT_IN_LIST;
 use self::command::{
     AuthenticatorClientPinParameters, AuthenticatorGetAssertionParameters,
-    AuthenticatorMakeCredentialParameters, Command, MAX_CREDENTIAL_COUNT_IN_LIST,
+    AuthenticatorMakeCredentialParameters, Command,
 };
+#[cfg(feature = "with_ctap2_1")]
+use self::data_formats::AuthenticatorTransport;
 use self::data_formats::{
-    AuthenticatorTransport, ClientPinSubCommand, CoseKey, GetAssertionHmacSecretInput,
-    PackedAttestationStatement, PublicKeyCredentialDescriptor, PublicKeyCredentialParameter,
-    PublicKeyCredentialSource, PublicKeyCredentialType, PublicKeyCredentialUserEntity,
-    SignatureAlgorithm,
+    ClientPinSubCommand, CoseKey, GetAssertionHmacSecretInput, PackedAttestationStatement,
+    PublicKeyCredentialDescriptor, PublicKeyCredentialParameter, PublicKeyCredentialSource,
+    PublicKeyCredentialType, PublicKeyCredentialUserEntity, SignatureAlgorithm,
 };
 use self::hid::ChannelID;
 use self::key_material::{AAGUID, ATTESTATION_CERTIFICATE, ATTESTATION_PRIVATE_KEY};
@@ -100,7 +103,9 @@ pub const FIDO2_VERSION_STRING: &str = "FIDO_2_0";
 #[cfg(feature = "with_ctap1")]
 pub const U2F_VERSION_STRING: &str = "U2F_V2";
 
-pub const CREDENTIAL_PARAMETER: PublicKeyCredentialParameter = PublicKeyCredentialParameter {
+// We currently only support one algorithm for signatures: ES256.
+// This algorithm is requested in MakeCredential and advertized in GetInfo.
+pub const ES256_CRED_PARAM: PublicKeyCredentialParameter = PublicKeyCredentialParameter {
     cred_type: PublicKeyCredentialType::PublicKey,
     alg: SignatureAlgorithm::ES256,
 };
@@ -419,7 +424,7 @@ where
             }
         }
 
-        if !pub_key_cred_params.contains(&CREDENTIAL_PARAMETER) {
+        if !pub_key_cred_params.contains(&ES256_CRED_PARAM) {
             return Err(Ctap2StatusCode::CTAP2_ERR_UNSUPPORTED_ALGORITHM);
         }
 
@@ -757,6 +762,7 @@ where
             self.persistent_store.pin_hash().is_some(),
         );
         Ok(ResponseData::AuthenticatorGetInfo(
+            #[cfg(feature = "with_ctap2_1")]
             AuthenticatorGetInfoResponse {
                 versions: vec![
                     #[cfg(feature = "with_ctap1")]
@@ -770,14 +776,29 @@ where
                 pin_protocols: Some(vec![
                     CtapState::<R, CheckUserPresence>::PIN_PROTOCOL_VERSION,
                 ]),
-                max_credential_count_in_list: MAX_CREDENTIAL_COUNT_IN_LIST,
+                max_credential_count_in_list: MAX_CREDENTIAL_COUNT_IN_LIST.map(|c| c as u64),
                 // You can use ENCRYPTED_CREDENTIAL_ID_SIZE here, but if your
                 // browser passes that value, it might be used to fingerprint.
                 max_credential_id_length: None,
                 transports: Some(vec![AuthenticatorTransport::Usb]),
-                algorithms: Some(vec![CREDENTIAL_PARAMETER]),
+                algorithms: Some(vec![ES256_CRED_PARAM]),
                 firmware_version: None,
             },
+            #[cfg(not(feature = "with_ctap2_1"))]
+            AuthenticatorGetInfoResponse {
+                versions: vec![
+                    #[cfg(feature = "with_ctap1")]
+                    String::from(U2F_VERSION_STRING),
+                    String::from(FIDO2_VERSION_STRING),
+                ],
+                extensions: Some(vec![String::from("hmac-secret")]),
+                aaguid: *AAGUID,
+                options: Some(options_map),
+                max_msg_size: Some(1024),
+                pin_protocols: Some(vec![
+                    CtapState::<R, CheckUserPresence>::PIN_PROTOCOL_VERSION,
+                ]),
+            },
         ))
     }
 
@@ -1098,7 +1119,10 @@ mod test {
         let mut ctap_state = CtapState::new(&mut rng, user_immediately_present);
         let info_reponse = ctap_state.process_command(&[0x04], DUMMY_CHANNEL_ID);
 
+        #[cfg(feature = "with_ctap2_1")]
         let mut expected_response = vec![0x00, 0xA8, 0x01];
+        #[cfg(not(feature = "with_ctap2_1"))]
+        let mut expected_response = vec![0x00, 0xA6, 0x01];
         // The difference here is a longer array of supported versions.
         #[cfg(not(feature = "with_ctap1"))]
         expected_response.extend(&[0x81, 0x68, 0x46, 0x49, 0x44, 0x4F, 0x5F, 0x32, 0x5F, 0x30]);
@@ -1112,10 +1136,13 @@ mod test {
             0x03, 0x50,
         ]);
         expected_response.extend(AAGUID);
+        expected_response.extend(&[
+            0x04, 0xA3, 0x62, 0x72, 0x6B, 0xF5, 0x62, 0x75, 0x70, 0xF5, 0x69, 0x63, 0x6C, 0x69,
+            0x65, 0x6E, 0x74, 0x50, 0x69, 0x6E, 0xF4, 0x05, 0x19, 0x04, 0x00, 0x06, 0x81, 0x01,
+        ]);
+        #[cfg(feature = "with_ctap2_1")]
         expected_response.extend(
             [
-                0x04, 0xA3, 0x62, 0x72, 0x6B, 0xF5, 0x62, 0x75, 0x70, 0xF5, 0x69, 0x63, 0x6C, 0x69,
-                0x65, 0x6E, 0x74, 0x50, 0x69, 0x6E, 0xF4, 0x05, 0x19, 0x04, 0x00, 0x06, 0x81, 0x01,
                 0x09, 0x81, 0x63, 0x75, 0x73, 0x62, 0x0A, 0x81, 0xA2, 0x63, 0x61, 0x6C, 0x67, 0x26,
                 0x64, 0x74, 0x79, 0x70, 0x65, 0x6A, 0x70, 0x75, 0x62, 0x6C, 0x69, 0x63, 0x2D, 0x6B,
                 0x65, 0x79,
@@ -1139,7 +1166,7 @@ mod test {
             user_display_name: None,
             user_icon: None,
         };
-        let pub_key_cred_params = vec![CREDENTIAL_PARAMETER];
+        let pub_key_cred_params = vec![ES256_CRED_PARAM];
         let options = MakeCredentialOptions {
             rk: true,
             uv: false,
diff --git a/src/ctap/response.rs b/src/ctap/response.rs
index 9960f6c..389b82d 100644
--- a/src/ctap/response.rs
+++ b/src/ctap/response.rs
@@ -12,9 +12,11 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#[cfg(feature = "with_ctap2_1")]
+use super::data_formats::{AuthenticatorTransport, PublicKeyCredentialParameter};
 use super::data_formats::{
-    AuthenticatorTransport, CoseKey, PackedAttestationStatement, PublicKeyCredentialDescriptor,
-    PublicKeyCredentialParameter, PublicKeyCredentialUserEntity,
+    CoseKey, PackedAttestationStatement, PublicKeyCredentialDescriptor,
+    PublicKeyCredentialUserEntity,
 };
 use alloc::collections::BTreeMap;
 use alloc::string::String;
@@ -102,21 +104,27 @@ impl From<AuthenticatorGetAssertionResponse> for cbor::Value {
 #[cfg_attr(test, derive(PartialEq))]
 #[cfg_attr(any(test, feature = "debug_ctap"), derive(Debug))]
 pub struct AuthenticatorGetInfoResponse {
-    // TODO(kaczmarczyck) add fields from 2.1
+    // TODO(kaczmarczyck) add maxAuthenticatorConfigLength and defaultCredProtect
     pub versions: Vec<String>,
     pub extensions: Option<Vec<String>>,
     pub aaguid: [u8; 16],
     pub options: Option<BTreeMap<String, bool>>,
     pub max_msg_size: Option<u64>,
     pub pin_protocols: Option<Vec<u64>>,
+    #[cfg(feature = "with_ctap2_1")]
     pub max_credential_count_in_list: Option<u64>,
+    #[cfg(feature = "with_ctap2_1")]
     pub max_credential_id_length: Option<u64>,
+    #[cfg(feature = "with_ctap2_1")]
     pub transports: Option<Vec<AuthenticatorTransport>>,
+    #[cfg(feature = "with_ctap2_1")]
     pub algorithms: Option<Vec<PublicKeyCredentialParameter>>,
+    #[cfg(feature = "with_ctap2_1")]
     pub firmware_version: Option<u64>,
 }
 
 impl From<AuthenticatorGetInfoResponse> for cbor::Value {
+    #[cfg(feature = "with_ctap2_1")]
     fn from(get_info_response: AuthenticatorGetInfoResponse) -> Self {
         let AuthenticatorGetInfoResponse {
             versions,
@@ -154,6 +162,35 @@ impl From<AuthenticatorGetInfoResponse> for cbor::Value {
             0x0E => firmware_version,
         }
     }
+
+    #[cfg(not(feature = "with_ctap2_1"))]
+    fn from(get_info_response: AuthenticatorGetInfoResponse) -> Self {
+        let AuthenticatorGetInfoResponse {
+            versions,
+            extensions,
+            aaguid,
+            options,
+            max_msg_size,
+            pin_protocols,
+        } = get_info_response;
+
+        let options_cbor: Option<cbor::Value> = options.map(|options| {
+            let option_map: BTreeMap<_, _> = options
+                .into_iter()
+                .map(|(key, value)| (cbor_text!(key), cbor_bool!(value)))
+                .collect();
+            cbor_map_btree!(option_map)
+        });
+
+        cbor_map_options! {
+            0x01 => cbor_array_vec!(versions),
+            0x02 => extensions.map(|vec| cbor_array_vec!(vec)),
+            0x03 => &aaguid,
+            0x04 => options_cbor,
+            0x05 => max_msg_size,
+            0x06 => pin_protocols.map(|vec| cbor_array_vec!(vec)),
+        }
+    }
 }
 
 #[cfg_attr(test, derive(PartialEq))]
@@ -183,6 +220,8 @@ impl From<AuthenticatorClientPinResponse> for cbor::Value {
 #[cfg(test)]
 mod test {
     use super::super::data_formats::PackedAttestationStatement;
+    #[cfg(feature = "with_ctap2_1")]
+    use super::super::ES256_CRED_PARAM;
     use super::*;
 
     #[test]
@@ -243,17 +282,58 @@ mod test {
             options: None,
             max_msg_size: None,
             pin_protocols: None,
+            #[cfg(feature = "with_ctap2_1")]
             max_credential_count_in_list: None,
+            #[cfg(feature = "with_ctap2_1")]
             max_credential_id_length: None,
+            #[cfg(feature = "with_ctap2_1")]
             transports: None,
+            #[cfg(feature = "with_ctap2_1")]
             algorithms: None,
+            #[cfg(feature = "with_ctap2_1")]
             firmware_version: None,
         };
         let response_cbor: Option<cbor::Value> =
             ResponseData::AuthenticatorGetInfo(get_info_response).into();
         let expected_cbor = cbor_map_options! {
-            1 => cbor_array_vec![vec!["FIDO_2_0"]],
-            3 => vec![0x00; 16],
+            0x01 => cbor_array_vec![vec!["FIDO_2_0"]],
+            0x03 => vec![0x00; 16],
+        };
+        assert_eq!(response_cbor, Some(expected_cbor));
+    }
+
+    #[test]
+    #[cfg(feature = "with_ctap2_1")]
+    fn test_get_info_optionals_into_cbor() {
+        let mut options_map = BTreeMap::new();
+        options_map.insert(String::from("rk"), true);
+        let get_info_response = AuthenticatorGetInfoResponse {
+            versions: vec!["FIDO_2_0".to_string()],
+            extensions: Some(vec!["extension".to_string()]),
+            aaguid: [0x00; 16],
+            options: Some(options_map),
+            max_msg_size: Some(1024),
+            pin_protocols: Some(vec![1]),
+            max_credential_count_in_list: Some(20),
+            max_credential_id_length: Some(256),
+            transports: Some(vec![AuthenticatorTransport::Usb]),
+            algorithms: Some(vec![ES256_CRED_PARAM]),
+            firmware_version: Some(0),
+        };
+        let response_cbor: Option<cbor::Value> =
+            ResponseData::AuthenticatorGetInfo(get_info_response).into();
+        let expected_cbor = cbor_map_options! {
+            0x01 => cbor_array_vec![vec!["FIDO_2_0"]],
+            0x02 => cbor_array_vec![vec!["extension"]],
+            0x03 => vec![0x00; 16],
+            0x04 => cbor_map! {"rk" => true},
+            0x05 => 1024,
+            0x06 => cbor_array_vec![vec![1]],
+            0x07 => 20,
+            0x08 => 256,
+            0x09 => cbor_array_vec![vec!["usb"]],
+            0x0A => cbor_array_vec![vec![ES256_CRED_PARAM]],
+            0x0E => 0,
         };
         assert_eq!(response_cbor, Some(expected_cbor));
     }
-- 
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