add a fuzzing target for the parser

CONTRIBUTING.md

@@ -118,6 +118,10 @@ You can follow [this link][lrus] to look for issues like this.
 
 [lrus]: https://github.com/uuid-rs/uuid/issues?q=is%3Aissue+is%3Aopen+sort%3Aupdated-asc
 
+# Fuzzing
+We use [`cargo fuzz`] to fuzz test various parts of `uuid`. See their guide
+for more details on what fuzzing is and how to run the tests yourself.
+
 # Helpful Links
 [Helpful Links]: #helpful-links
 
@@ -133,3 +137,4 @@ seasoned developers, some useful places to look for information are:
 [u-r-l-o]: https://users.rust-lang.org
 [Discussions]: https://github.com/uuid-rs/uuid/discussions
 [search existing issues]: https://github.com/uuid-rs/uuid/search?q=&type=Issues&utf8=%E2%9C%93
+[`cargo fuzz`]: https://rust-fuzz.github.io/book/cargo-fuzz.html

fuzz/.gitignore

@@ -0,0 +1,3 @@
+target
+corpus
+artifacts

fuzz/Cargo.toml

@@ -0,0 +1,25 @@
+[package]
+name = "uuid-fuzz"
+version = "0.0.0"
+authors = ["Automatically generated"]
+publish = false
+edition = "2018"
+
+[package.metadata]
+cargo-fuzz = true
+
+[dependencies]
+libfuzzer-sys = "0.4"
+
+[dependencies.uuid]
+path = ".."
+
+# Prevent this from interfering with workspaces
+[workspace]
+members = ["."]
+
+[[bin]]
+name = "fuzz_target_parse"
+path = "fuzz_targets/fuzz_target_parse.rs"
+test = false
+doc = false

fuzz/corpus/fuzz_target_parse/guid

@@ -0,0 +1 @@
+{6d93bade-bd9f-4e13-8914-9474e1e3567b}

fuzz/corpus/fuzz_target_parse/hyphenated

@@ -0,0 +1 @@
+67e55044-10b1-426f-9247-bb680e5fe0c8

fuzz/corpus/fuzz_target_parse/simple

@@ -0,0 +1 @@
+67e5504410b1426f9247bb680e5fe0c8

fuzz/corpus/fuzz_target_parse/urn

@@ -0,0 +1 @@
+urn:uuid:67e55044-10b1-426f-9247-bb680e5fe0c8

fuzz/fuzz_targets/fuzz_target_parse.rs

@@ -0,0 +1,12 @@
+#![no_main]
+use libfuzzer_sys::fuzz_target;
+
+use std::str;
+use uuid::Uuid;
+
+fuzz_target!(|data: &[u8]| {
+    if let Ok(uuid) = str::from_utf8(data) {
+        // Ensure the parser doesn't panic
+        let _ = Uuid::parse_str(uuid);
+    }
+});