Add fuzing for Key CRDT (#1444)

This has duplicated changes with #1442 that will likely conflict and need rebase.

Reviewed-on: https://git.deuxfleurs.fr/Deuxfleurs/garage/pulls/1444
Reviewed-by: Alex <lx@deuxfleurs.fr>

fuzz/Cargo.toml

@@ -50,3 +50,10 @@ path = "fuzz_targets/admin_api_token_crdt.rs"
 test = false
 doc = false
 bench = false
+
+[[bin]]
+name = "key_crdt"
+path = "fuzz_targets/key_crdt.rs"
+test = false
+doc = false
+bench = false

fuzz/fuzz_targets/key_crdt.rs

@@ -0,0 +1,43 @@
+#![no_main]
+
+use garage_fuzz::check_crdt_laws;
+use garage_model::key_table::{Key, KeyParams};
+use garage_model::permission::BucketKeyPerm;
+use garage_util::crdt;
+use garage_util::data::Uuid;
+use libfuzzer_sys::fuzz_target;
+
+type Input = (
+	bool,
+	crdt::Lww<String>,
+	crdt::Lww<Option<u64>>,
+	crdt::Lww<bool>,
+	crdt::Map<Uuid, BucketKeyPerm>,
+	crdt::LwwMap<String, Option<Uuid>>,
+);
+
+fn make(input: Input) -> Key {
+	let (deleted, name, expiration, allow_create_bucket, authorized_buckets, local_aliases) = input;
+	let state = if deleted {
+		crdt::Deletable::Deleted
+	} else {
+		crdt::Deletable::present(KeyParams {
+			created: None,
+			secret_key: String::new(),
+			name,
+			expiration,
+			allow_create_bucket,
+			authorized_buckets,
+			local_aliases,
+		})
+	};
+	Key {
+		key_id: String::new(),
+		state,
+	}
+}
+
+fuzz_target!(|inputs: (Input, Input, Input)| {
+	let (a, b, c) = inputs;
+	check_crdt_laws(make(a), make(b), make(c));
+});