From fae1e7e012571201fd51c547ba4fb6044be9aeb5 Mon Sep 17 00:00:00 2001
From: MarcoFalke <*~=`'#}+{/-|&$^_@721217.xyz>
Date: Wed, 6 Dec 2023 12:03:56 +0100
Subject: [PATCH 1/2] fuzz: p2p: Detect peer deadlocks

---
 src/test/fuzz/process_messages.cpp | 14 +++++++++-----
 src/test/util/net.h                |  5 ++++-
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/src/test/fuzz/process_messages.cpp b/src/test/fuzz/process_messages.cpp
index b7e2e04b4b..3f722f60ee 100644
--- a/src/test/fuzz/process_messages.cpp
+++ b/src/test/fuzz/process_messages.cpp
@@ -78,13 +78,17 @@ FUZZ_TARGET(process_messages, .init = initialize_process_messages)
 
         connman.FlushSendBuffer(random_node);
         (void)connman.ReceiveMsgFrom(random_node, std::move(net_msg));
-        random_node.fPauseSend = false;
 
-        try {
-            connman.ProcessMessagesOnce(random_node);
-        } catch (const std::ios_base::failure&) {
+        bool more_work{true};
+        while (more_work) { // Ensure that every message is eventually processed in some way or another
+            random_node.fPauseSend = false;
+
+            try {
+                more_work = connman.ProcessMessagesOnce(random_node);
+            } catch (const std::ios_base::failure&) {
+            }
+            g_setup->m_node.peerman->SendMessages(&random_node);
         }
-        g_setup->m_node.peerman->SendMessages(&random_node);
     }
     SyncWithValidationInterfaceQueue();
     g_setup->m_node.connman->StopNodes();
diff --git a/src/test/util/net.h b/src/test/util/net.h
index 59c4ddb4b1..d91d801132 100644
--- a/src/test/util/net.h
+++ b/src/test/util/net.h
@@ -70,7 +70,10 @@ struct ConnmanTestMsg : public CConnman {
                    bool relay_txs)
         EXCLUSIVE_LOCKS_REQUIRED(NetEventsInterface::g_msgproc_mutex);
 
-    void ProcessMessagesOnce(CNode& node) EXCLUSIVE_LOCKS_REQUIRED(NetEventsInterface::g_msgproc_mutex) { m_msgproc->ProcessMessages(&node, flagInterruptMsgProc); }
+    bool ProcessMessagesOnce(CNode& node) EXCLUSIVE_LOCKS_REQUIRED(NetEventsInterface::g_msgproc_mutex)
+    {
+        return m_msgproc->ProcessMessages(&node, flagInterruptMsgProc);
+    }
 
     void NodeReceiveMsgBytes(CNode& node, Span<const uint8_t> msg_bytes, bool& complete) const;
 

From 9f265d88253ed464413dea5614fa13dea0d8cfd5 Mon Sep 17 00:00:00 2001
From: dergoegge <n.goeggi@gmail.com>
Date: Wed, 6 Dec 2023 16:03:57 +0000
Subject: [PATCH 2/2] fuzz: Detect deadlocks in process_message

---
 src/test/fuzz/process_message.cpp | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/src/test/fuzz/process_message.cpp b/src/test/fuzz/process_message.cpp
index 6392f03d4e..acb03ac5fc 100644
--- a/src/test/fuzz/process_message.cpp
+++ b/src/test/fuzz/process_message.cpp
@@ -79,14 +79,23 @@ FUZZ_TARGET(process_message, .init = initialize_process_message)
     const auto mock_time = ConsumeTime(fuzzed_data_provider);
     SetMockTime(mock_time);
 
+    CSerializedNetMsg net_msg;
+    net_msg.m_type = random_message_type;
     // fuzzed_data_provider is fully consumed after this call, don't use it
-    DataStream random_bytes_data_stream{fuzzed_data_provider.ConsumeRemainingBytes<unsigned char>()};
-    try {
-        g_setup->m_node.peerman->ProcessMessage(p2p_node, random_message_type, random_bytes_data_stream,
-                                                GetTime<std::chrono::microseconds>(), std::atomic<bool>{false});
-    } catch (const std::ios_base::failure&) {
+    net_msg.data = fuzzed_data_provider.ConsumeRemainingBytes<unsigned char>();
+
+    connman.FlushSendBuffer(p2p_node);
+    (void)connman.ReceiveMsgFrom(p2p_node, std::move(net_msg));
+
+    bool more_work{true};
+    while (more_work) {
+        p2p_node.fPauseSend = false;
+        try {
+            more_work = connman.ProcessMessagesOnce(p2p_node);
+        } catch (const std::ios_base::failure&) {
+        }
+        g_setup->m_node.peerman->SendMessages(&p2p_node);
     }
-    g_setup->m_node.peerman->SendMessages(&p2p_node);
     SyncWithValidationInterfaceQueue();
     g_setup->m_node.connman->StopNodes();
 }