6 files changed, 56 insertions, 4 deletions
diff --git a/src/Makefile.test_util.include b/src/Makefile.test_util.include
index d7bc73defb..0621da8ddf 100644
--- a/src/Makefile.test_util.include
+++ b/src/Makefile.test_util.include
@@ -15,6 +15,7 @@ TEST_UTIL_H = \
     test/util/setup_common.h \
     test/util/str.h \
     test/util/transaction_utils.h \
+    test/util/validation.h \
     test/util/wallet.h
 
 libtest_util_a_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES) $(MINIUPNPC_CPPFLAGS) $(EVENT_CFLAGS) $(EVENT_PTHREADS_CFLAGS)
@@ -27,6 +28,7 @@ libtest_util_a_SOURCES = \
   test/util/setup_common.cpp \
   test/util/str.cpp \
   test/util/transaction_utils.cpp \
+  test/util/validation.cpp \
   test/util/wallet.cpp \
   $(TEST_UTIL_H)
 
diff --git a/src/test/fuzz/process_message.cpp b/src/test/fuzz/process_message.cpp
index 3ef03137ec..9390399878 100644
--- a/src/test/fuzz/process_message.cpp
+++ b/src/test/fuzz/process_message.cpp
@@ -16,6 +16,7 @@
 #include <test/util/mining.h>
 #include <test/util/net.h>
 #include <test/util/setup_common.h>
+#include <test/util/validation.h>
 #include <util/memory.h>
 #include <validationinterface.h>
 #include <version.h>
@@ -63,10 +64,14 @@ void test_one_input(const std::vector<uint8_t>& buffer)
 {
     FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
     ConnmanTestMsg& connman = *(ConnmanTestMsg*)g_setup->m_node.connman.get();
+    TestChainState& chainstate = *(TestChainState*)&g_setup->m_node.chainman->ActiveChainstate();
+    chainstate.ResetIbd();
     const std::string random_message_type{fuzzed_data_provider.ConsumeBytesAsString(CMessageHeader::COMMAND_SIZE).c_str()};
     if (!LIMIT_TO_MESSAGE_TYPE.empty() && random_message_type != LIMIT_TO_MESSAGE_TYPE) {
         return;
     }
+    const bool jump_out_of_ibd{fuzzed_data_provider.ConsumeBool()};
+    if (jump_out_of_ibd) chainstate.JumpOutOfIbd();
     CDataStream random_bytes_data_stream{fuzzed_data_provider.ConsumeRemainingBytes<unsigned char>(), SER_NETWORK, PROTOCOL_VERSION};
     CNode& p2p_node = *MakeUnique<CNode>(0, ServiceFlags(NODE_NETWORK | NODE_WITNESS | NODE_BLOOM), 0, INVALID_SOCKET, CAddress{CService{in_addr{0x0100007f}, 7777}, NODE_NETWORK}, 0, 0, CAddress{}, std::string{}, ConnectionType::OUTBOUND_FULL_RELAY).release();
     p2p_node.fSuccessfullyConnected = true;
@@ -76,7 +81,7 @@ void test_one_input(const std::vector<uint8_t>& buffer)
     g_setup->m_node.peerman->InitializeNode(&p2p_node);
     try {
         g_setup->m_node.peerman->ProcessMessage(p2p_node, random_message_type, random_bytes_data_stream,
-                                                   GetTime<std::chrono::microseconds>(), std::atomic<bool>{false});
+                                                GetTime<std::chrono::microseconds>(), std::atomic<bool>{false});
     } catch (const std::ios_base::failure&) {
     }
     SyncWithValidationInterfaceQueue();
diff --git a/src/test/fuzz/process_messages.cpp b/src/test/fuzz/process_messages.cpp
index f722eeac3a..19ea92b750 100644
--- a/src/test/fuzz/process_messages.cpp
+++ b/src/test/fuzz/process_messages.cpp
@@ -12,6 +12,7 @@
 #include <test/util/mining.h>
 #include <test/util/net.h>
 #include <test/util/setup_common.h>
+#include <test/util/validation.h>
 #include <util/memory.h>
 #include <validation.h>
 #include <validationinterface.h>
@@ -39,7 +40,10 @@ void test_one_input(const std::vector<uint8_t>& buffer)
     FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
 
     ConnmanTestMsg& connman = *(ConnmanTestMsg*)g_setup->m_node.connman.get();
+    TestChainState& chainstate = *(TestChainState*)&g_setup->m_node.chainman->ActiveChainstate();
+    chainstate.ResetIbd();
     std::vector<CNode*> peers;
+    bool jump_out_of_ibd{false};
 
     const auto num_peers_to_add = fuzzed_data_provider.ConsumeIntegralInRange(1, 3);
     for (int i = 0; i < num_peers_to_add; ++i) {
@@ -58,6 +62,8 @@ void test_one_input(const std::vector<uint8_t>& buffer)
     }
 
     while (fuzzed_data_provider.ConsumeBool()) {
+        if (!jump_out_of_ibd) jump_out_of_ibd = fuzzed_data_provider.ConsumeBool();
+        if (jump_out_of_ibd && chainstate.IsInitialBlockDownload()) chainstate.JumpOutOfIbd();
         const std::string random_message_type{fuzzed_data_provider.ConsumeBytesAsString(CMessageHeader::COMMAND_SIZE).c_str()};
 
         CSerializedNetMsg net_msg;
diff --git a/src/test/util/validation.cpp b/src/test/util/validation.cpp
new file mode 100644
index 0000000000..1aed492c3c
--- /dev/null
+++ b/src/test/util/validation.cpp
@@ -0,0 +1,22 @@
+// Copyright (c) 2020 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <test/util/validation.h>
+
+#include <util/check.h>
+#include <util/time.h>
+#include <validation.h>
+
+void TestChainState::ResetIbd()
+{
+    m_cached_finished_ibd = false;
+    assert(IsInitialBlockDownload());
+}
+
+void TestChainState::JumpOutOfIbd()
+{
+    Assert(IsInitialBlockDownload());
+    m_cached_finished_ibd = true;
+    Assert(!IsInitialBlockDownload());
+}
diff --git a/src/test/util/validation.h b/src/test/util/validation.h
new file mode 100644
index 0000000000..b13aa0be60
--- /dev/null
+++ b/src/test/util/validation.h
@@ -0,0 +1,17 @@
+// Copyright (c) 2020 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_TEST_UTIL_VALIDATION_H
+#define BITCOIN_TEST_UTIL_VALIDATION_H
+
+#include <validation.h>
+
+struct TestChainState : public CChainState {
+    /** Reset the ibd cache to its initial state */
+    void ResetIbd();
+    /** Toggle IsInitialBlockDownload from true to false */
+    void JumpOutOfIbd();
+};
+
+#endif // BITCOIN_TEST_UTIL_VALIDATION_H
diff --git a/src/validation.h b/src/validation.h
index 3d9fa92c15..ffb038ad75 100644
--- a/src/validation.h
+++ b/src/validation.h
@@ -503,9 +503,9 @@ enum class CoinsCacheSizeState
  * whereas block information and metadata independent of the current tip is
  * kept in `BlockMetadataManager`.
  */
-class CChainState {
-private:
-
+class CChainState
+{
+protected:
     /**
      * Every received block is assigned a unique and increasing identifier, so we
      * know which one to give priority in case of a fork.