merge bitcoin#22029: Improve transport deserialization fuzz test coverage

src/Makefile.test.include

@@ -287,7 +287,7 @@ test_fuzz_fuzz_SOURCES = \
   test/fuzz/net_permissions.cpp \
   test/fuzz/netaddress.cpp \
   test/fuzz/netbase_dns_lookup.cpp \
-  test/fuzz/p2p_transport_deserializer.cpp \
+  test/fuzz/p2p_transport_serialization.cpp \
   test/fuzz/parse_hd_keypath.cpp \
   test/fuzz/parse_iso8601.cpp \
   test/fuzz/parse_numbers.cpp \

src/test/fuzz/p2p_transport_deserializer.cpp

@@ -1,43 +0,0 @@
-// Copyright (c) 2019 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 <chainparams.h>
-#include <net.h>
-#include <protocol.h>
-#include <test/fuzz/fuzz.h>
-
-#include <cassert>
-#include <cstdint>
-#include <limits>
-#include <optional>
-#include <vector>
-
-void initialize_p2p_transport_deserializer()
-{
-    SelectParams(CBaseChainParams::REGTEST);
-}
-
-FUZZ_TARGET_INIT(p2p_transport_deserializer, initialize_p2p_transport_deserializer)
-{
-    // Construct deserializer, with a dummy NodeId
-    V1TransportDeserializer deserializer{Params(), (NodeId)0, SER_NETWORK, INIT_PROTO_VERSION};
-    Span<const uint8_t> msg_bytes{buffer};
-    while (msg_bytes.size() > 0) {
-        const int handled = deserializer.Read(msg_bytes);
-        if (handled < 0) {
-            break;
-        }
-        if (deserializer.Complete()) {
-            const int64_t m_time = std::numeric_limits<int64_t>::max();
-            uint32_t out_err_raw_size{0};
-            std::optional<CNetMessage> result{deserializer.GetMessage(m_time, out_err_raw_size)};
-            if (result) {
-                assert(result->m_command.size() <= CMessageHeader::COMMAND_SIZE);
-                assert(result->m_raw_message_size <= buffer.size());
-                assert(result->m_raw_message_size == CMessageHeader::HEADER_SIZE + result->m_message_size);
-                assert(result->m_time == m_time);
-            }
-        }
-    }
-}

src/test/fuzz/p2p_transport_serialization.cpp

@@ -0,0 +1,85 @@
+// Copyright (c) 2019 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 <chainparams.h>
+#include <hash.h>
+#include <net.h>
+#include <netmessagemaker.h>
+#include <protocol.h>
+#include <test/fuzz/FuzzedDataProvider.h>
+#include <test/fuzz/fuzz.h>
+
+#include <cassert>
+#include <cstdint>
+#include <limits>
+#include <optional>
+#include <vector>
+
+void initialize_p2p_transport_serialization()
+{
+    SelectParams(CBaseChainParams::REGTEST);
+}
+
+FUZZ_TARGET_INIT(p2p_transport_serialization, initialize_p2p_transport_serialization)
+{
+    // Construct deserializer, with a dummy NodeId
+    V1TransportDeserializer deserializer{Params(), (NodeId)0, SER_NETWORK, INIT_PROTO_VERSION};
+    V1TransportSerializer serializer{};
+    FuzzedDataProvider fuzzed_data_provider{buffer.data(), buffer.size()};
+
+    auto checksum_assist = fuzzed_data_provider.ConsumeBool();
+    auto magic_bytes_assist = fuzzed_data_provider.ConsumeBool();
+    std::vector<uint8_t> mutable_msg_bytes;
+
+    auto header_bytes_remaining = CMessageHeader::HEADER_SIZE;
+    if (magic_bytes_assist) {
+        auto msg_start = Params().MessageStart();
+        for (size_t i = 0; i < CMessageHeader::MESSAGE_SIZE_SIZE; ++i) {
+            mutable_msg_bytes.push_back(msg_start[i]);
+        }
+        header_bytes_remaining -= CMessageHeader::MESSAGE_SIZE_SIZE;
+    }
+
+    if (checksum_assist) {
+        header_bytes_remaining -= CMessageHeader::CHECKSUM_SIZE;
+    }
+
+    auto header_random_bytes = fuzzed_data_provider.ConsumeBytes<uint8_t>(header_bytes_remaining);
+    mutable_msg_bytes.insert(mutable_msg_bytes.end(), header_random_bytes.begin(), header_random_bytes.end());
+    auto payload_bytes = fuzzed_data_provider.ConsumeRemainingBytes<uint8_t>();
+
+    if (checksum_assist && mutable_msg_bytes.size() == CMessageHeader::CHECKSUM_OFFSET) {
+        CHash256 hasher;
+        unsigned char hsh[32];
+        hasher.Write(payload_bytes);
+        hasher.Finalize(hsh);
+        for (size_t i = 0; i < CMessageHeader::CHECKSUM_SIZE; ++i) {
+           mutable_msg_bytes.push_back(hsh[i]);
+        }
+    }
+
+    mutable_msg_bytes.insert(mutable_msg_bytes.end(), payload_bytes.begin(), payload_bytes.end());
+    Span<const uint8_t> msg_bytes{mutable_msg_bytes};
+    while (msg_bytes.size() > 0) {
+        const int handled = deserializer.Read(msg_bytes);
+        if (handled < 0) {
+            break;
+        }
+        if (deserializer.Complete()) {
+            const int64_t m_time = std::numeric_limits<int64_t>::max();
+            uint32_t out_err_raw_size{0};
+            std::optional<CNetMessage> result{deserializer.GetMessage(m_time, out_err_raw_size)};
+            if (result) {
+                assert(result->m_command.size() <= CMessageHeader::COMMAND_SIZE);
+                assert(result->m_raw_message_size <= mutable_msg_bytes.size());
+                assert(result->m_raw_message_size == CMessageHeader::HEADER_SIZE + result->m_message_size);
+                assert(result->m_time == m_time);
+
+                std::vector<unsigned char> header;
+                auto msg = CNetMsgMaker{result->m_recv.GetVersion()}.Make(result->m_command, MakeUCharSpan(result->m_recv));
+                serializer.prepareForTransport(msg, header);
+            }
+        }
+    }
+}