Make chanmon_fail_consistency slightly less aggressive

This resolves some crashes that both afl and honggfuzz found.

fuzz/fuzz_targets/chanmon_fail_consistency.rs

@@ -52,7 +52,7 @@ use secp256k1::Secp256k1;
 
 use std::mem;
 use std::cmp::Ordering;
-use std::collections::{HashSet, HashMap};
+use std::collections::{HashSet, hash_map, HashMap};
 use std::sync::{Arc,Mutex};
 use std::sync::atomic;
 use std::io::Cursor;
@@ -80,6 +80,7 @@ impl Writer for VecWriter {
  }
 }
 
+static mut IN_RESTORE: bool = false;
 pub struct TestChannelMonitor {
  pub simple_monitor: Arc<channelmonitor::SimpleManyChannelMonitor<OutPoint>>,
  pub update_ret: Mutex<Result<(), channelmonitor::ChannelMonitorUpdateErr>>,
@@ -107,7 +108,18 @@ impl channelmonitor::ManyChannelMonitor for TestChannelMonitor {
  let mut ser = VecWriter(Vec::new());
  monitor.write_for_disk(&mut ser).unwrap();
  self.latest_good_update.lock().unwrap().insert(funding_txo, ser.0);
- self.latest_update_good.lock().unwrap().insert(funding_txo, true);
+ match self.latest_update_good.lock().unwrap().entry(funding_txo) {
+ hash_map::Entry::Vacant(mut e) => { e.insert(true); },
+ hash_map::Entry::Occupied(mut e) => {
+ if !e.get() && unsafe { IN_RESTORE } {
+ // Technically we can't consider an update to be "good" unless we're doing
+ // it in response to a test_restore_channel_monitor as the channel may
+ // still be waiting on such a call, so only set us to good if we're in the
+ // middle of a restore call.
+ e.insert(true);
+ }
+ },
+ }
  self.should_update_manager.store(true, atomic::Ordering::Relaxed);
  } else {
  self.latest_update_good.lock().unwrap().insert(funding_txo, false);
@@ -619,9 +631,9 @@ pub fn do_test(data: &[u8]) {
  0x03 => *monitor_a.update_ret.lock().unwrap() = Ok(()),
  0x04 => *monitor_b.update_ret.lock().unwrap() = Ok(()),
  0x05 => *monitor_c.update_ret.lock().unwrap() = Ok(()),
- 0x06 => nodes[0].test_restore_channel_monitor(),
- 0x07 => nodes[1].test_restore_channel_monitor(),
- 0x08 => nodes[2].test_restore_channel_monitor(),
+ 0x06 => { unsafe { IN_RESTORE = true }; nodes[0].test_restore_channel_monitor(); unsafe { IN_RESTORE = false }; },
+ 0x07 => { unsafe { IN_RESTORE = true }; nodes[1].test_restore_channel_monitor(); unsafe { IN_RESTORE = false }; },
+ 0x08 => { unsafe { IN_RESTORE = true }; nodes[2].test_restore_channel_monitor(); unsafe { IN_RESTORE = false }; },
  0x09 => send_payment!(nodes[0], (&nodes[1], chan_a)),
  0x0a => send_payment!(nodes[1], (&nodes[0], chan_a)),
  0x0b => send_payment!(nodes[1], (&nodes[2], chan_b)),