tests: Add fuzzing harness for functions/classes in protocol.h

Author: practicalswift

src/Makefile.test.include

@@ -83,6 +83,7 @@ FUZZ_TARGETS = \
   test/fuzz/process_message_tx \
   test/fuzz/process_message_verack \
   test/fuzz/process_message_version \
+  test/fuzz/protocol \
   test/fuzz/psbt \
   test/fuzz/psbt_input_deserialize \
   test/fuzz/psbt_output_deserialize \
@@ -766,6 +767,12 @@ test_fuzz_process_message_version_LDADD = $(FUZZ_SUITE_LD_COMMON)
 test_fuzz_process_message_version_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(LIBTOOL_APP_LDFLAGS)
 test_fuzz_process_message_version_SOURCES = $(FUZZ_SUITE) test/fuzz/process_message.cpp
 
+test_fuzz_protocol_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES)
+test_fuzz_protocol_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
+test_fuzz_protocol_LDADD = $(FUZZ_SUITE_LD_COMMON)
+test_fuzz_protocol_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(LIBTOOL_APP_LDFLAGS)
+test_fuzz_protocol_SOURCES = $(FUZZ_SUITE) test/fuzz/protocol.cpp
+
 test_fuzz_psbt_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES)
 test_fuzz_psbt_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
 test_fuzz_psbt_LDADD = $(FUZZ_SUITE_LD_COMMON)

src/test/fuzz/protocol.cpp

@@ -0,0 +1,32 @@
+// 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 <optional.h>
+#include <protocol.h>
+#include <test/fuzz/FuzzedDataProvider.h>
+#include <test/fuzz/fuzz.h>
+#include <test/fuzz/util.h>
+
+#include <cstdint>
+#include <stdexcept>
+#include <vector>
+
+void test_one_input(const std::vector<uint8_t>& buffer)
+{
+    FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
+    const Optional<CInv> inv = ConsumeDeserializable<CInv>(fuzzed_data_provider);
+    if (!inv) {
+        return;
+    }
+    try {
+        (void)inv->GetCommand();
+    } catch (const std::out_of_range&) {
+    }
+    (void)inv->ToString();
+    const Optional<CInv> another_inv = ConsumeDeserializable<CInv>(fuzzed_data_provider);
+    if (!another_inv) {
+        return;
+    }
+    (void)(*inv < *another_inv);
+}