Add a fuzzer for system_properties.
This could be improved by testing private functions like read_raw or
by improving wait fuzzing so that it will fuzz things it cannot write,
but those seem like little enough gain for more work, so we'll start
with this.
Test: Run fuzzer.
Change-Id: I4c5a04fd3e18a5c975a0e000fbae1a236699192d
diff --git a/system_properties_fuzzer.rs b/system_properties_fuzzer.rs
new file mode 100644
index 0000000..5950ac2
--- /dev/null
+++ b/system_properties_fuzzer.rs
@@ -0,0 +1,118 @@
+// Copyright 2021, The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#![allow(missing_docs)]
+#![allow(unused_must_use)]
+#![no_main]
+
+use libfuzzer_sys::arbitrary::Arbitrary;
+use libfuzzer_sys::fuzz_target;
+use rustutils::system_properties;
+use std::cell::RefCell;
+use std::sync::Arc;
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::{fmt, thread, time};
+
+thread_local! {
+ static COUNTER: RefCell<u64> = RefCell::new(0);
+}
+
+#[derive(Arbitrary, Clone, Debug)]
+enum WritableProperty {
+ Fuzzer1,
+ Fuzzer2,
+}
+
+#[derive(Arbitrary, Clone, Debug)]
+enum Property {
+ KeystoreBootLevel,
+ Random { name: String },
+ Unique,
+ Writable { prop: WritableProperty },
+}
+
+impl fmt::Display for Property {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ write!(f, "{}", match self {
+ Property::KeystoreBootLevel => "keystore.boot_level".to_string(),
+ Property::Random { name } => name.to_string(),
+ Property::Unique => COUNTER.with(|counter| {
+ let val = *counter.borrow();
+ *counter.borrow_mut() += 1;
+ format!("unique.fuzz.prop.{}", val)
+ }),
+ Property::Writable { prop } => prop.to_string(),
+ })
+ }
+}
+
+impl fmt::Display for WritableProperty {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ write!(f, "{}", match self {
+ WritableProperty::Fuzzer1 => "unique.fuzz.prop".to_string(),
+ WritableProperty::Fuzzer2 => "unique.fuzz.two.prop".to_string(),
+ })
+ }
+}
+
+#[derive(Arbitrary, Debug)]
+enum Command {
+ Read { prop: Property },
+ Write { prop: WritableProperty, value: String },
+ WatcherRead { prop: Property },
+ WatcherWait { value: u8 },
+}
+
+fuzz_target!(|commands: Vec<Command>| {
+ for command in commands {
+ match command {
+ Command::Read { prop } => {
+ system_properties::read(&prop.to_string());
+ }
+ Command::Write { prop, value } => {
+ system_properties::write(&prop.to_string(), &value);
+ }
+ Command::WatcherRead { prop } => {
+ if let Ok(mut watcher) = system_properties::PropertyWatcher::new(&prop.to_string()) {
+ watcher.read(|_n, v| Ok(v.to_string()));
+ }
+ }
+ Command::WatcherWait { value } => {
+ // We want to ensure that we choose a property that can be written,
+ // or else we'd just have to implement a timeout and do nothing,
+ // so we use a hardcoded valid property.
+ let prop_str = "keystore.boot_level";
+ let waited = Arc::new(AtomicBool::new(false));
+ let waited_clone = waited.clone();
+ // Spawn a thread that will wait for a change to the property.
+ let waiter = thread::spawn(move || {
+ let result = match system_properties::PropertyWatcher::new(prop_str) {
+ Ok(mut watcher) => watcher.wait(),
+ Err(e) => Err(e),
+ };
+ waited_clone.store(true, Ordering::Relaxed);
+ result
+ });
+ // Write the property in a loop (so we're sure to follow the wait call).
+ let mut cur_value = value;
+ while !waited.load(Ordering::Relaxed) {
+ thread::sleep(time::Duration::from_millis(1));
+ system_properties::write(prop_str, &cur_value.to_string());
+ cur_value = cur_value.wrapping_add(1);
+ }
+ waiter.join();
+ }
+ }
+ }
+});