fuzz: add higher level functional fuzzing

fuzz/Cargo.toml

@@ -11,6 +11,7 @@ cargo-fuzz = true
 ctap-types = { version = "0.2.0", features = ["arbitrary"] }
 libfuzzer-sys = "0.4"
 trussed-staging = { version = "0.3.0", features = ["chunked", "hkdf", "virt"] }
+arbitrary = "1.3"
 
 [dependencies.fido-authenticator]
 path = ".."
@@ -22,6 +23,13 @@ test = false
 doc = false
 bench = false
 
+[[bin]]
+name = "functional"
+path = "fuzz_targets/functional.rs"
+test = false
+doc = false
+bench = false
+
 [patch.crates-io]
 ctap-types = { git = "https://github.com/trussed-dev/ctap-types.git", rev = "72eb68b61e3f14957c5ab89bd22f776ac860eb62" }
 littlefs2 = { git = "https://github.com/trussed-dev/littlefs2.git", rev = "2b45a7559ff44260c6dd693e4cb61f54ae5efc53" }

fuzz/fuzz_targets/functional.rs

@@ -0,0 +1,57 @@
+#![no_main]
+
+use fido_authenticator::{Authenticator, Config, Conforming};
+use trussed_staging::virt;
+
+use ctap_types::{
+    ctap1::Authenticator as _,
+    ctap1::{authenticate, register},
+    ctap2::make_credential,
+    ctap2::Authenticator as _,
+};
+
+use arbitrary::Arbitrary;
+
+use libfuzzer_sys::fuzz_target;
+
+#[derive(Debug, Arbitrary, Eq, PartialEq)]
+enum Action<'a> {
+    MakeCredential {
+        request: make_credential::Request<'a>,
+    },
+    Register {
+        request: register::Request<'a>,
+    },
+    Authenticate {
+        request: authenticate::Request<'a>,
+    },
+}
+
+fuzz_target!(|actions: Vec<Action<'_>>| {
+    virt::with_ram_client("fido", |client| {
+        let mut authenticator = Authenticator::new(
+            client,
+            Conforming {},
+            Config {
+                max_msg_size: 0,
+                skip_up_timeout: None,
+                max_resident_credential_count: Some(20),
+                large_blobs: None,
+                nfc_transport: false,
+            },
+        );
+        for action in actions {
+            match action {
+                Action::MakeCredential { request: req } => {
+                    authenticator.make_credential(&req).ok();
+                }
+                Action::Register { request: req } => {
+                    authenticator.register(&req).ok();
+                }
+                Action::Authenticate { request: req } => {
+                    authenticator.authenticate(&req).ok();
+                }
+            }
+        }
+    });
+});