Merge bitcoin#20437: fuzz: Avoid time-based "non-determinism" in fuzz…

…ing harnesses by using mocked GetTime()

8c09c0c fuzz: Avoid time-based "non-determinism" in fuzzing harnesses by using mocked GetTime() (practicalswift)

Pull request description:

  Avoid time-based "non-determinism" in fuzzing harnesses by using mocked `GetTime()`.

  Prior to this commit the fuzzing harnesses `banman`, `connman`, `net` and `rbf` had time-based "non-determinism". `addrman` is fixed in bitcoin#20425. `process_message` and `process_messages` are left to fix: simply using mock time is not enough for them due to interaction with `IsInitialBlockDownload()`.

  See [`doc/fuzzing.md`](https://github.com/bitcoin/bitcoin/blob/master/doc/fuzzing.md) for information on how to fuzz Bitcoin Core. Don't forget to contribute any coverage increasing inputs you find to the [Bitcoin Core fuzzing corpus repo](https://github.com/bitcoin-core/qa-assets).

  Happy fuzzing :)

ACKs for top commit:
  MarcoFalke:
    review ACK 8c09c0c
  practicalswift:
    > review ACK [8c09c0c](bitcoin@8c09c0c)

Tree-SHA512: 32dfbead3dfd18cf4ff56dc2ea341aa977441b4e19a54879cf54fa5820c7e2b14b92c7e238d32fd785654f3b28cc82826ae66c03e94c292633c63c41196ba9a8

src/test/fuzz/banman.cpp

@@ -36,6 +36,7 @@ FUZZ_TARGET_INIT(banman, initialize_banman)
     // complexity of the input size).
     int limit_max_ops{300};
     FuzzedDataProvider fuzzed_data_provider{buffer.data(), buffer.size()};
+    SetMockTime(ConsumeTime(fuzzed_data_provider));
     const fs::path banlist_file = GetDataDir() / "fuzzed_banlist.dat";
     fs::remove(banlist_file);
     {

src/test/fuzz/connman.cpp

@@ -23,6 +23,7 @@ void initialize_connman()
 FUZZ_TARGET_INIT(connman, initialize_connman)
 {
     FuzzedDataProvider fuzzed_data_provider{buffer.data(), buffer.size()};
+    SetMockTime(ConsumeTime(fuzzed_data_provider));
     CAddrMan addrman;
     CConnman connman{fuzzed_data_provider.ConsumeIntegral<uint64_t>(), fuzzed_data_provider.ConsumeIntegral<uint64_t>(), addrman};
     CNetAddr random_netaddr;

src/test/fuzz/net.cpp

@@ -28,7 +28,7 @@ void initialize_net()
 FUZZ_TARGET_INIT(net, initialize_net)
 {
     FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
-
+    SetMockTime(ConsumeTime(fuzzed_data_provider));
     const std::optional<CAddress> address = ConsumeDeserializable<CAddress>(fuzzed_data_provider);
     if (!address) {
         return;