tests: Add fuzzing harness for CBlockPolicyEstimator::{Read,Write} (policy/fees.h)

Author: practicalswift

src/Makefile.test.include

@@ -77,6 +77,7 @@ FUZZ_TARGETS = \
   test/fuzz/partial_merkle_tree_deserialize \
   test/fuzz/partially_signed_transaction_deserialize \
   test/fuzz/policy_estimator \
+  test/fuzz/policy_estimator_io \
   test/fuzz/pow \
   test/fuzz/prefilled_transaction_deserialize \
   test/fuzz/prevector \
@@ -761,6 +762,12 @@ test_fuzz_policy_estimator_LDADD = $(FUZZ_SUITE_LD_COMMON)
 test_fuzz_policy_estimator_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(LIBTOOL_APP_LDFLAGS)
 test_fuzz_policy_estimator_SOURCES = test/fuzz/policy_estimator.cpp
 
+test_fuzz_policy_estimator_io_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES)
+test_fuzz_policy_estimator_io_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
+test_fuzz_policy_estimator_io_LDADD = $(FUZZ_SUITE_LD_COMMON)
+test_fuzz_policy_estimator_io_LDFLAGS = $(RELDFLAGS) $(AM_LDFLAGS) $(LIBTOOL_APP_LDFLAGS)
+test_fuzz_policy_estimator_io_SOURCES = test/fuzz/policy_estimator_io.cpp
+
 test_fuzz_pow_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES)
 test_fuzz_pow_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
 test_fuzz_pow_LDADD = $(FUZZ_SUITE_LD_COMMON)

src/test/fuzz/policy_estimator.cpp

@@ -14,6 +14,11 @@
 #include <string>
 #include <vector>
 
+void initialize()
+{
+    InitializeFuzzingContext();
+}
+
 void test_one_input(const std::vector<uint8_t>& buffer)
 {
     FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
@@ -66,4 +71,10 @@ void test_one_input(const std::vector<uint8_t>& buffer)
         (void)block_policy_estimator.estimateSmartFee(fuzzed_data_provider.ConsumeIntegral<int>(), fuzzed_data_provider.ConsumeBool() ? &fee_calculation : nullptr, fuzzed_data_provider.ConsumeBool());
         (void)block_policy_estimator.HighestTargetTracked(fuzzed_data_provider.PickValueInArray({FeeEstimateHorizon::SHORT_HALFLIFE, FeeEstimateHorizon::MED_HALFLIFE, FeeEstimateHorizon::LONG_HALFLIFE}));
     }
+    {
+        FuzzedAutoFileProvider fuzzed_auto_file_provider = ConsumeAutoFile(fuzzed_data_provider);
+        CAutoFile fuzzed_auto_file = fuzzed_auto_file_provider.open();
+        block_policy_estimator.Write(fuzzed_auto_file);
+        block_policy_estimator.Read(fuzzed_auto_file);
+    }
 }

src/test/fuzz/policy_estimator_io.cpp

@@ -0,0 +1,28 @@
+// 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 <policy/fees.h>
+#include <test/fuzz/FuzzedDataProvider.h>
+#include <test/fuzz/fuzz.h>
+#include <test/fuzz/util.h>
+
+#include <cstdint>
+#include <vector>
+
+void initialize()
+{
+    InitializeFuzzingContext();
+}
+
+void test_one_input(const std::vector<uint8_t>& buffer)
+{
+    FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
+    FuzzedAutoFileProvider fuzzed_auto_file_provider = ConsumeAutoFile(fuzzed_data_provider);
+    CAutoFile fuzzed_auto_file = fuzzed_auto_file_provider.open();
+    // Re-using block_policy_estimator across runs to avoid costly creation of CBlockPolicyEstimator object.
+    static CBlockPolicyEstimator block_policy_estimator;
+    if (block_policy_estimator.Read(fuzzed_auto_file)) {
+        block_policy_estimator.Write(fuzzed_auto_file);
+    }
+}