Move 3 pure constants to new file

src/api/customization.rs

@@ -68,6 +68,16 @@ pub trait Customization {
     /// the minimum PIN length with the minPinLength extension.
     fn default_min_pin_length_rp_ids(&self) -> &[&str];
 
+    /// Enforces the alwaysUv option.
+    ///
+    /// When setting to true, commands require a PIN.
+    /// Also, alwaysUv can not be disabled by commands.
+    ///
+    /// A certification (additional to FIDO Alliance's) might require enforcing
+    /// alwaysUv. Otherwise, users should have the choice to configure alwaysUv.
+    /// Calling toggleAlwaysUv is preferred over enforcing alwaysUv here.
+    fn enforce_always_uv(&self) -> bool;
+
     /// Maximum message size send for CTAP commands.
     ///
     /// The maximum value is 7609, as HID packets can not encode longer messages.
@@ -77,6 +87,28 @@ pub trait Customization {
     /// this value.
     fn max_msg_size(&self) -> usize;
 
+    /// Sets the number of consecutive failed PINs before blocking interaction.
+    ///
+    /// # Invariant
+    ///
+    /// - CTAP2.0: Maximum PIN retries must be 8.
+    /// - CTAP2.1: Maximum PIN retries must be 8 at most.
+    ///
+    /// The fail retry counter is reset after entering the correct PIN.
+    fn max_pin_retries(&self) -> u8;
+
+    /// Enables or disables signature counters.
+    ///
+    /// The signature counter is currently implemented as a global counter.
+    /// The specification strongly suggests to have per-credential counters.
+    /// Implementing those means you can't have an infinite amount of server-side
+    /// credentials anymore. Also, since counters need frequent writes on the
+    /// persistent storage, we might need a flash friendly implementation. This
+    /// solution is a compromise to be compatible with U2F and not wasting storage.
+    ///
+    /// https://www.w3.org/TR/webauthn/#signature-counter
+    fn use_signature_counter(&self) -> bool;
+
     // ###########################################################################
     // Constants for performance optimization or adapting to different hardware.
     //
@@ -102,18 +134,24 @@ pub trait Customization {
 
 #[derive(Clone)]
 pub struct CustomizationImpl {
+    pub default_cred_protect: Option<CredentialProtectionPolicy>,
     pub default_min_pin_length: u8,
     pub default_min_pin_length_rp_ids: &'static [&'static str],
-    pub default_cred_protect: Option<CredentialProtectionPolicy>,
+    pub enforce_always_uv: bool,
     pub max_msg_size: usize,
+    pub max_pin_retries: u8,
+    pub use_signature_counter: bool,
     pub max_rp_ids_length: usize,
 }
 
 pub const DEFAULT_CUSTOMIZATION: CustomizationImpl = CustomizationImpl {
     default_min_pin_length: 4,
     default_min_pin_length_rp_ids: &[],
+    enforce_always_uv: false,
     default_cred_protect: None,
     max_msg_size: 7609,
+    max_pin_retries: 8,
+    use_signature_counter: true,
     max_rp_ids_length: 8,
 };
 
@@ -130,10 +168,22 @@ impl Customization for CustomizationImpl {
         self.default_min_pin_length_rp_ids
     }
 
+    fn enforce_always_uv(&self) -> bool {
+        self.enforce_always_uv
+    }
+
     fn max_msg_size(&self) -> usize {
         self.max_msg_size
     }
 
+    fn max_pin_retries(&self) -> u8 {
+        self.max_pin_retries
+    }
+
+    fn use_signature_counter(&self) -> bool {
+        self.use_signature_counter
+    }
+
     fn max_rp_ids_length(&self) -> usize {
         self.max_rp_ids_length
     }
@@ -151,6 +201,11 @@ pub fn is_valid(customization: &impl Customization) -> bool {
         return false;
     }
 
+    // Max pin retries must be less or equal than 8.
+    if customization.max_pin_retries() > 8 {
+        return false;
+    }
+
     // Default min pin length rp ids must be non-empty if max rp ids length is 0.
     if customization.max_rp_ids_length() == 0
         && customization.default_min_pin_length_rp_ids().is_empty()

src/ctap/config_command.rs

@@ -123,7 +123,7 @@ pub fn process_config(
 #[cfg(test)]
 mod test {
     use super::*;
-    use crate::ctap::customization::ENFORCE_ALWAYS_UV;
+    use crate::api::customization::Customization;
     use crate::ctap::data_formats::PinUvAuthProtocol;
     use crate::ctap::pin_protocol::authenticate_pin_uv_auth_token;
     use crate::env::test::TestEnv;
@@ -180,7 +180,7 @@ mod test {
             pin_uv_auth_protocol: None,
         };
         let config_response = process_config(&mut env, &mut client_pin, config_params);
-        if ENFORCE_ALWAYS_UV {
+        if env.customization().enforce_always_uv() {
             assert_eq!(
                 config_response,
                 Err(Ctap2StatusCode::CTAP2_ERR_OPERATION_DENIED)
@@ -210,7 +210,7 @@ mod test {
             pin_uv_auth_protocol: Some(pin_uv_auth_protocol),
         };
         let config_response = process_config(&mut env, &mut client_pin, config_params);
-        if ENFORCE_ALWAYS_UV {
+        if env.customization().enforce_always_uv() {
             assert_eq!(
                 config_response,
                 Err(Ctap2StatusCode::CTAP2_ERR_OPERATION_DENIED)

src/ctap/ctap1.rs

@@ -344,8 +344,9 @@ impl Ctap1Command {
 
 #[cfg(test)]
 mod test {
-    use super::super::{key_material, CREDENTIAL_ID_SIZE, USE_SIGNATURE_COUNTER};
+    use super::super::{key_material, CREDENTIAL_ID_SIZE};
     use super::*;
+    use crate::api::customization::Customization;
     use crate::clock::TEST_CLOCK_FREQUENCY_HZ;
     use crate::env::test::TestEnv;
     use crypto::Hash256;
@@ -643,8 +644,8 @@ mod test {
         assert_eq!(response, Err(Ctap1StatusCode::SW_WRONG_DATA));
     }
 
-    fn check_signature_counter(response: &[u8; 4], signature_counter: u32) {
+    fn check_signature_counter(env: &mut impl Env, response: &[u8; 4], signature_counter: u32) {
-        if USE_SIGNATURE_COUNTER {
+        if env.customization().use_signature_counter() {
             assert_eq!(u32::from_be_bytes(*response), signature_counter);
         } else {
             assert_eq!(response, &[0x00, 0x00, 0x00, 0x00]);
@@ -673,9 +674,11 @@ mod test {
             Ctap1Command::process_command(&mut env, &message, &mut ctap_state, CtapInstant::new(0))
                 .unwrap();
         assert_eq!(response[0], 0x01);
+        let global_signature_counter = storage::global_signature_counter(&mut env).unwrap();
         check_signature_counter(
+            &mut env,
             array_ref!(response, 1, 4),
-            storage::global_signature_counter(&mut env).unwrap(),
+            global_signature_counter,
         );
     }
 
@@ -706,9 +709,11 @@ mod test {
         )
         .unwrap();
         assert_eq!(response[0], 0x01);
+        let global_signature_counter = storage::global_signature_counter(&mut env).unwrap();
         check_signature_counter(
+            &mut env,
             array_ref!(response, 1, 4),
-            storage::global_signature_counter(&mut env).unwrap(),
+            global_signature_counter,
         );
     }
 

src/ctap/customization.rs

@@ -19,16 +19,6 @@
 
 use crate::ctap::data_formats::EnterpriseAttestationMode;
 
-/// Enforces the alwaysUv option.
-///
-/// When setting to true, commands require a PIN.
-/// Also, alwaysUv can not be disabled by commands.
-///
-/// A certification (additional to FIDO Alliance's) might require enforcing
-/// alwaysUv. Otherwise, users should have the choice to configure alwaysUv.
-/// Calling toggleAlwaysUv is preferred over enforcing alwaysUv here.
-pub const ENFORCE_ALWAYS_UV: bool = false;
-
 /// Allows usage of enterprise attestation.
 ///
 /// # Invariant
@@ -71,16 +61,6 @@ pub const ENTERPRISE_ATTESTATION_MODE: Option<EnterpriseAttestationMode> = None;
 /// VendorFacilitated.
 pub const ENTERPRISE_RP_ID_LIST: &[&str] = &[];
 
-/// Sets the number of consecutive failed PINs before blocking interaction.
-///
-/// # Invariant
-///
-/// - CTAP2.0: Maximum PIN retries must be 8.
-/// - CTAP2.1: Maximum PIN retries must be 8 at most.
-///
-/// The fail retry counter is reset after entering the correct PIN.
-pub const MAX_PIN_RETRIES: u8 = 8;
-
 /// Enables or disables basic attestation for FIDO2.
 ///
 /// # Invariant
@@ -97,18 +77,6 @@ pub const MAX_PIN_RETRIES: u8 = 8;
 /// https://www.w3.org/TR/webauthn/#attestation
 pub const USE_BATCH_ATTESTATION: bool = false;
 
-/// Enables or disables signature counters.
-///
-/// The signature counter is currently implemented as a global counter.
-/// The specification strongly suggests to have per-credential counters.
-/// Implementing those means you can't have an infinite amount of server-side
-/// credentials anymore. Also, since counters need frequent writes on the
-/// persistent storage, we might need a flash friendly implementation. This
-/// solution is a compromise to be compatible with U2F and not wasting storage.
-///
-/// https://www.w3.org/TR/webauthn/#signature-counter
-pub const USE_SIGNATURE_COUNTER: bool = true;
-
 // ###########################################################################
 // Constants for performance optimization or adapting to different hardware.
 //
@@ -178,7 +146,6 @@ mod test {
         } else {
             assert!(ENTERPRISE_RP_ID_LIST.is_empty());
         }
-        assert!(MAX_PIN_RETRIES <= 8);
         assert!(MAX_CRED_BLOB_LENGTH >= 32);
         if let Some(count) = MAX_CREDENTIAL_COUNT_IN_LIST {
             assert!(count >= 1);

src/ctap/mod.rs

@@ -45,7 +45,7 @@ use self::credential_management::process_credential_management;
 use self::crypto_wrapper::{aes256_cbc_decrypt, aes256_cbc_encrypt};
 use self::customization::{
     ENTERPRISE_ATTESTATION_MODE, ENTERPRISE_RP_ID_LIST, MAX_CREDENTIAL_COUNT_IN_LIST,
-    MAX_CRED_BLOB_LENGTH, MAX_LARGE_BLOB_ARRAY_SIZE, USE_BATCH_ATTESTATION, USE_SIGNATURE_COUNTER,
+    MAX_CRED_BLOB_LENGTH, MAX_LARGE_BLOB_ARRAY_SIZE, USE_BATCH_ATTESTATION,
 };
 use self::data_formats::{
     AuthenticatorTransport, CoseKey, CoseSignature, CredentialProtectionPolicy,
@@ -421,7 +421,7 @@ impl CtapState {
         &mut self,
         env: &mut impl Env,
     ) -> Result<(), Ctap2StatusCode> {
-        if USE_SIGNATURE_COUNTER {
+        if env.customization().use_signature_counter() {
             let increment = env.rng().gen_uniform_u32x8()[0] % 8 + 1;
             storage::incr_global_signature_counter(env, increment)?;
         }
@@ -1398,7 +1398,7 @@ impl CtapState {
         let mut auth_data = vec![];
         auth_data.extend(rp_id_hash);
         auth_data.push(flag_byte);
-        // The global counter is only increased if USE_SIGNATURE_COUNTER is true.
+        // The global counter is only increased if use_signature_counter() is true.
         // It uses a big-endian representation.
         let mut signature_counter = [0u8; 4];
         BigEndian::write_u32(

src/ctap/storage.rs

@@ -16,9 +16,7 @@ mod key;
 
 use crate::api::customization::Customization;
 use crate::ctap::client_pin::PIN_AUTH_LENGTH;
-use crate::ctap::customization::{
+use crate::ctap::customization::{MAX_LARGE_BLOB_ARRAY_SIZE, MAX_SUPPORTED_RESIDENT_KEYS};
-    ENFORCE_ALWAYS_UV, MAX_LARGE_BLOB_ARRAY_SIZE, MAX_PIN_RETRIES, MAX_SUPPORTED_RESIDENT_KEYS,
-};
 use crate::ctap::data_formats::{
     extract_array, extract_text_string, CredentialProtectionPolicy, PublicKeyCredentialSource,
     PublicKeyCredentialUserEntity,
@@ -360,7 +358,7 @@ pub fn set_pin(
 /// Returns the number of remaining PIN retries.
 pub fn pin_retries(env: &mut impl Env) -> Result<u8, Ctap2StatusCode> {
     match env.store().find(key::PIN_RETRIES)? {
-        None => Ok(MAX_PIN_RETRIES),
+        None => Ok(env.customization().max_pin_retries()),
         Some(value) if value.len() == 1 => Ok(value[0]),
         _ => Err(Ctap2StatusCode::CTAP2_ERR_VENDOR_INTERNAL_ERROR),
     }
@@ -596,7 +594,7 @@ pub fn enable_enterprise_attestation(env: &mut impl Env) -> Result<(), Ctap2Stat
 
 /// Returns whether alwaysUv is enabled.
 pub fn has_always_uv(env: &mut impl Env) -> Result<bool, Ctap2StatusCode> {
-    if ENFORCE_ALWAYS_UV {
+    if env.customization().enforce_always_uv() {
         return Ok(true);
     }
     match env.store().find(key::ALWAYS_UV)? {
@@ -608,7 +606,7 @@ pub fn has_always_uv(env: &mut impl Env) -> Result<bool, Ctap2StatusCode> {
 
 /// Enables alwaysUv, when disabled, and vice versa.
 pub fn toggle_always_uv(env: &mut impl Env) -> Result<(), Ctap2StatusCode> {
-    if ENFORCE_ALWAYS_UV {
+    if env.customization().enforce_always_uv() {
         return Err(Ctap2StatusCode::CTAP2_ERR_OPERATION_DENIED);
     }
     if has_always_uv(env)? {
@@ -1061,10 +1059,13 @@ mod test {
         let mut env = TestEnv::new();
 
         // The pin retries is initially at the maximum.
-        assert_eq!(pin_retries(&mut env), Ok(MAX_PIN_RETRIES));
+        assert_eq!(
+            pin_retries(&mut env),
+            Ok(env.customization().max_pin_retries())
+        );
 
         // Decrementing the pin retries decrements the pin retries.
-        for retries in (0..MAX_PIN_RETRIES).rev() {
+        for retries in (0..env.customization().max_pin_retries()).rev() {
             decr_pin_retries(&mut env).unwrap();
             assert_eq!(pin_retries(&mut env), Ok(retries));
         }
@@ -1075,7 +1076,10 @@ mod test {
 
         // Resetting the pin retries resets the pin retries.
         reset_pin_retries(&mut env).unwrap();
-        assert_eq!(pin_retries(&mut env), Ok(MAX_PIN_RETRIES));
+        assert_eq!(
+            pin_retries(&mut env),
+            Ok(env.customization().max_pin_retries())
+        );
     }
 
     #[test]
@@ -1250,7 +1254,7 @@ mod test {
     fn test_always_uv() {
         let mut env = TestEnv::new();
 
-        if ENFORCE_ALWAYS_UV {
+        if env.customization().enforce_always_uv() {
             assert!(has_always_uv(&mut env).unwrap());
             assert_eq!(
                 toggle_always_uv(&mut env),

src/ctap/storage/key.rs

@@ -115,7 +115,7 @@ make_partition! {
 
     /// The number of PIN retries.
     ///
-    /// If the entry is absent, the number of PIN retries is `MAX_PIN_RETRIES`.
+    /// If the entry is absent, the number of PIN retries is `Customization::max_pin_retries()`.
     PIN_RETRIES = 2044;
 
     /// The PIN hash and length.

src/env/test/customization.rs

@@ -4,11 +4,14 @@ use crate::api::customization::{Customization, CustomizationImpl};
 use crate::ctap::data_formats::CredentialProtectionPolicy;
 
 pub struct TestCustomization {
+    pub default_cred_protect: Option<CredentialProtectionPolicy>,
     pub default_min_pin_length: u8,
     default_min_pin_length_rp_ids_backing_store: Vec<String>,
     default_min_pin_length_rp_ids: Vec<*const str>,
-    pub default_cred_protect: Option<CredentialProtectionPolicy>,
+    pub enforce_always_uv: bool,
     pub max_msg_size: usize,
+    pub max_pin_retries: u8,
+    pub use_signature_counter: bool,
     pub max_rp_ids_length: usize,
 }
 
@@ -38,10 +41,22 @@ impl Customization for TestCustomization {
         unsafe { from_raw_parts(rp_ids, length) }
     }
 
+    fn enforce_always_uv(&self) -> bool {
+        self.enforce_always_uv
+    }
+
     fn max_msg_size(&self) -> usize {
         self.max_msg_size
     }
 
+    fn max_pin_retries(&self) -> u8 {
+        self.max_pin_retries
+    }
+
+    fn use_signature_counter(&self) -> bool {
+        self.use_signature_counter
+    }
+
     fn max_rp_ids_length(&self) -> usize {
         self.max_rp_ids_length
     }
@@ -50,10 +65,13 @@ impl Customization for TestCustomization {
 impl From<CustomizationImpl> for TestCustomization {
     fn from(c: CustomizationImpl) -> Self {
         let CustomizationImpl {
+            default_cred_protect,
             default_min_pin_length,
             default_min_pin_length_rp_ids,
-            default_cred_protect,
+            enforce_always_uv,
             max_msg_size,
+            max_pin_retries,
+            use_signature_counter,
             max_rp_ids_length,
         } = c;
 
@@ -63,11 +81,14 @@ impl From<CustomizationImpl> for TestCustomization {
             .collect::<Vec<_>>();
 
         let mut ret = Self {
+            default_cred_protect,
             default_min_pin_length,
             default_min_pin_length_rp_ids_backing_store,
             default_min_pin_length_rp_ids: vec![],
-            default_cred_protect,
+            enforce_always_uv,
             max_msg_size,
+            max_pin_retries,
+            use_signature_counter,
             max_rp_ids_length,
         };