Add a fuzzer to check that IndexedMap is equivalent to BTreeMap

Author: TheBlueMatt

fuzz/src/bin/gen_target.sh

@@ -14,6 +14,7 @@ GEN_TEST peer_crypt
 GEN_TEST process_network_graph
 GEN_TEST router
 GEN_TEST zbase32
+GEN_TEST indexedmap
 
 GEN_TEST msg_accept_channel msg_targets::
 GEN_TEST msg_announcement_signatures msg_targets::

fuzz/src/indexedmap.rs

@@ -0,0 +1,138 @@
+// This file is Copyright its original authors, visible in version control
+// history.
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+
+use lightning::util::indexed_map::{IndexedMap, self};
+use std::collections::{BTreeMap, btree_map};
+use hashbrown::HashSet;
+
+use crate::utils::test_logger;
+
+// Note that while we take the trees by &mut here
+fn check_eq(btree: &BTreeMap<u8, u8>, indexed: &IndexedMap<u8, u8>) {
+	assert_eq!(btree.len(), indexed.len());
+	assert_eq!(btree.is_empty(), indexed.is_empty());
+
+	let mut btree_clone = btree.clone();
+	assert!(btree_clone == *btree);
+	let mut indexed_clone = indexed.clone();
+	assert!(indexed_clone == *indexed);
+
+	for k in 0..=255 {
+		assert_eq!(btree.contains_key(&k), indexed.contains_key(&k));
+		assert_eq!(btree.get(&k), indexed.get(&k));
+
+		let btree_entry = btree_clone.entry(k);
+		let indexed_entry = indexed_clone.entry(k);
+		match btree_entry {
+			btree_map::Entry::Occupied(mut bo) => {
+				if let indexed_map::Entry::Occupied(mut io) = indexed_entry {
+					assert_eq!(bo.get(), io.get());
+					assert_eq!(bo.get_mut(), io.get_mut());
+				} else { panic!(); }
+			},
+			btree_map::Entry::Vacant(_) => {
+				if let indexed_map::Entry::Vacant(_) = indexed_entry {
+				} else { panic!(); }
+			}
+		}
+	}
+
+	const STRIDE: u8 = 16;
+	for k in 0..=255/STRIDE {
+		let lower_bound = k * STRIDE;
+		let upper_bound = lower_bound + (STRIDE - 1);
+		let mut btree_iter = btree.range(lower_bound..=upper_bound);
+		let mut indexed_iter = indexed.range(lower_bound..=upper_bound);
+		loop {
+			let b_v = btree_iter.next();
+			let i_v = indexed_iter.next();
+			assert_eq!(b_v, i_v);
+			if b_v.is_none() { break; }
+		}
+	}
+
+	let mut key_set = HashSet::with_capacity(256);
+	for k in indexed.unordered_keys() {
+		assert!(key_set.insert(*k));
+		assert!(btree.contains_key(k));
+	}
+	assert_eq!(key_set.len(), btree.len());
+
+	key_set.clear();
+	for (k, v) in indexed.unordered_iter() {
+		assert!(key_set.insert(*k));
+		assert_eq!(btree.get(k).unwrap(), v);
+	}
+	assert_eq!(key_set.len(), btree.len());
+
+	key_set.clear();
+	for (k, v) in indexed_clone.unordered_iter_mut() {
+		assert!(key_set.insert(*k));
+		assert_eq!(btree.get(k).unwrap(), v);
+	}
+	assert_eq!(key_set.len(), btree.len());
+}
+
+#[inline]
+pub fn do_test(data: &[u8]) {
+	if data.len() % 2 != 0 { return; }
+	let mut btree = BTreeMap::new();
+	let mut indexed = IndexedMap::new();
+
+	// Read in k-v pairs from the input and insert them into the maps then check that the maps are
+	// equivalent in every way we can read them.
+	for tuple in data.windows(2) {
+		let prev_value_b = btree.insert(tuple[0], tuple[1]);
+		let prev_value_i = indexed.insert(tuple[0], tuple[1]);
+		assert_eq!(prev_value_b, prev_value_i);
+	}
+	check_eq(&btree, &indexed);
+
+	// Now, modify the maps in all the ways we have to do so, checking that the maps remain
+	// equivalent as we go.
+	for (k, v) in indexed.unordered_iter_mut() {
+		*v = *k;
+		*btree.get_mut(k).unwrap() = *k;
+	}
+	check_eq(&btree, &indexed);
+
+	for k in 0..=255 {
+		match btree.entry(k) {
+			btree_map::Entry::Occupied(mut bo) => {
+				if let indexed_map::Entry::Occupied(mut io) = indexed.entry(k) {
+					if k < 64 {
+						*io.get_mut() ^= 0xff;
+						*bo.get_mut() ^= 0xff;
+					} else if k < 128 {
+						*io.into_mut() ^= 0xff;
+						*bo.get_mut() ^= 0xff;
+					} else {
+						assert_eq!(bo.remove_entry(), io.remove_entry());
+					}
+				} else { panic!(); }
+			},
+			btree_map::Entry::Vacant(bv) => {
+				if let indexed_map::Entry::Vacant(iv) = indexed.entry(k) {
+					bv.insert(k);
+					iv.insert(k);
+				} else { panic!(); }
+			},
+		}
+	}
+	check_eq(&btree, &indexed);
+}
+
+pub fn indexedmap_test<Out: test_logger::Output>(data: &[u8], _out: Out) {
+	do_test(data);
+}
+
+#[no_mangle]
+pub extern "C" fn indexedmap_run(data: *const u8, datalen: usize) {
+	do_test(unsafe { std::slice::from_raw_parts(data, datalen) });
+}

fuzz/src/lib.rs

@@ -17,6 +17,7 @@ pub mod utils;
 pub mod chanmon_deser;
 pub mod chanmon_consistency;
 pub mod full_stack;
+pub mod indexedmap;
 pub mod onion_message;
 pub mod peer_crypt;
 pub mod process_network_graph;

fuzz/targets.h

@@ -7,6 +7,7 @@ void peer_crypt_run(const unsigned char* data, size_t data_len);
 void process_network_graph_run(const unsigned char* data, size_t data_len);
 void router_run(const unsigned char* data, size_t data_len);
 void zbase32_run(const unsigned char* data, size_t data_len);
+void indexedmap_run(const unsigned char* data, size_t data_len);
 void msg_accept_channel_run(const unsigned char* data, size_t data_len);
 void msg_announcement_signatures_run(const unsigned char* data, size_t data_len);
 void msg_channel_reestablish_run(const unsigned char* data, size_t data_len);