From ade4d07bb5351f56be38547ed7e13848bba3b081 Mon Sep 17 00:00:00 2001
From: Arthur Carcano <arthur.carcano@ocamlpro.com>
Date: Tue, 28 Apr 2026 15:46:17 +0200
Subject: [PATCH] Set up fuzz infrastructure

---
 Cargo.lock           | 42 ++++++++++++++++++++++++++++++++++++++++++
 Cargo.toml           |  2 ++
 fuzz/.gitignore      |  4 ++++
 fuzz/Cargo.toml      | 20 ++++++++++++++++++++
 src/model/Cargo.toml |  2 ++
 src/util/Cargo.toml  |  2 ++
 src/util/crdt/lww.rs |  5 +++++
 src/util/data.rs     |  1 +
 8 files changed, 78 insertions(+)
 create mode 100644 fuzz/.gitignore
 create mode 100644 fuzz/Cargo.toml

diff --git a/Cargo.lock b/Cargo.lock
index a8621e8d..2e5d4211 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -145,6 +145,15 @@ version = "1.0.102"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7f202df86484c868dbad7eaa557ef785d5c66295e41b460ef922eca0723b842c"
 
+[[package]]
+name = "arbitrary"
+version = "1.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c3d036a3c4ab069c7b410a2ce876bd74808d2d0888a82667669f8e783a898bf1"
+dependencies = [
+ "derive_arbitrary",
+]
+
 [[package]]
 name = "arc-swap"
 version = "1.9.1"
@@ -1116,6 +1125,17 @@ dependencies = [
  "powerfmt",
 ]
 
+[[package]]
+name = "derive_arbitrary"
+version = "1.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1e567bd82dcff979e4b03460c307b3cdc9e96fde3d73bed1496d2bc75d9dd62a"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.114",
+]
+
 [[package]]
 name = "derive_more"
 version = "2.1.1"
@@ -1523,6 +1543,16 @@ dependencies = [
  "utoipa",
 ]
 
+[[package]]
+name = "garage-fuzz"
+version = "0.0.0"
+dependencies = [
+ "arbitrary",
+ "garage_model",
+ "garage_table",
+ "libfuzzer-sys",
+]
+
 [[package]]
 name = "garage_api_admin"
 version = "2.3.0"
@@ -1702,6 +1732,7 @@ dependencies = [
 name = "garage_model"
 version = "2.3.0"
 dependencies = [
+ "arbitrary",
  "argon2",
  "async-trait",
  "base64 0.22.1",
@@ -1810,6 +1841,7 @@ dependencies = [
 name = "garage_util"
 version = "2.3.0"
 dependencies = [
+ "arbitrary",
  "arc-swap",
  "async-trait",
  "blake2",
@@ -2934,6 +2966,16 @@ version = "0.2.185"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "52ff2c0fe9bc6cb6b14a0592c2ff4fa9ceb83eea9db979b0487cd054946a2b8f"
 
+[[package]]
+name = "libfuzzer-sys"
+version = "0.4.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f12a681b7dd8ce12bff52488013ba614b869148d54dd79836ab85aafdd53f08d"
+dependencies = [
+ "arbitrary",
+ "cc",
+]
+
 [[package]]
 name = "libsodium-sys"
 version = "0.2.7"
diff --git a/Cargo.toml b/Cargo.toml
index 9cd06778..d6876b15 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -16,6 +16,7 @@ members = [
 	"src/garage",
 	"src/k2v-client",
 	"src/format-table",
+    "fuzz",
 ]
 
 default-members = ["src/garage"]
@@ -40,6 +41,7 @@ k2v-client = { version = "0.0.4", path = "src/k2v-client" }
 
 # External crates from crates.io
 arc-swap = "1.8"
+arbitrary = { version = "1.4.2", features = ["derive"] }
 argon2 = "0.5"
 async-trait = "0.1"
 backtrace = "0.3"
diff --git a/fuzz/.gitignore b/fuzz/.gitignore
new file mode 100644
index 00000000..1a45eee7
--- /dev/null
+++ b/fuzz/.gitignore
@@ -0,0 +1,4 @@
+target
+corpus
+artifacts
+coverage
diff --git a/fuzz/Cargo.toml b/fuzz/Cargo.toml
new file mode 100644
index 00000000..b5cb21e5
--- /dev/null
+++ b/fuzz/Cargo.toml
@@ -0,0 +1,20 @@
+[package]
+name = "garage-fuzz"
+version = "0.0.0"
+publish = false
+edition = "2018"
+
+[package.metadata]
+cargo-fuzz = true
+
+[dependencies]
+arbitrary = { version = "1.4.2", features = ["derive"] }
+libfuzzer-sys = "0.4"
+
+[dependencies.garage_table]
+path = "../src/table"
+
+[dependencies.garage_model]
+path = "../src/model"
+features = ["arbitrary"]
+
diff --git a/src/model/Cargo.toml b/src/model/Cargo.toml
index 12683a0e..bb3d9aac 100644
--- a/src/model/Cargo.toml
+++ b/src/model/Cargo.toml
@@ -21,6 +21,7 @@ garage_block.workspace = true
 garage_util.workspace = true
 garage_net.workspace = true
 
+arbitrary = { optional = true, workspace = true }
 argon2.workspace = true
 async-trait.workspace = true
 blake2.workspace = true
@@ -46,6 +47,7 @@ k2v = ["garage_util/k2v"]
 lmdb = ["garage_db/lmdb"]
 sqlite = ["garage_db/sqlite"]
 fjall = ["garage_db/fjall"]
+arbitrary = ["dep:arbitrary","garage_util/arbitrary"]
 
 [lints]
 workspace = true
diff --git a/src/util/Cargo.toml b/src/util/Cargo.toml
index cbba213c..37799fd7 100644
--- a/src/util/Cargo.toml
+++ b/src/util/Cargo.toml
@@ -17,6 +17,7 @@ path = "lib.rs"
 garage_db.workspace = true
 garage_net.workspace = true
 
+arbitrary = { optional = true, workspace = true }
 arc-swap.workspace = true
 async-trait.workspace = true
 blake2.workspace = true
@@ -52,6 +53,7 @@ mktemp.workspace = true
 
 [features]
 k2v = []
+arbitrary = ["dep:arbitrary"]
 
 [lints]
 workspace = true
diff --git a/src/util/crdt/lww.rs b/src/util/crdt/lww.rs
index f8b03b85..e18ab5f3 100644
--- a/src/util/crdt/lww.rs
+++ b/src/util/crdt/lww.rs
@@ -84,6 +84,11 @@ where
 		self.v = new_value;
 	}
 
+	pub fn update2(&mut self, f: impl FnOnce(&mut T), time: u64) {
+		self.ts = std::cmp::max(self.ts + 1, time);
+		f(&mut self.v)
+	}
+
 	/// Get the timestamp currently associated with the value
 	pub fn timestamp(&self) -> u64 {
 		self.ts
diff --git a/src/util/data.rs b/src/util/data.rs
index e4ce316b..63c4379f 100644
--- a/src/util/data.rs
+++ b/src/util/data.rs
@@ -6,6 +6,7 @@ use std::fmt;
 
 /// An array of 32 bytes
 #[derive(Default, Clone, Hash, PartialEq, Eq, PartialOrd, Ord, Copy)]
+#[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
 pub struct FixedBytes32([u8; 32]);
 
 impl From<[u8; 32]> for FixedBytes32 {