From 69749fbe6a95f45eb7a695a5f89be87e55c91fb8 Mon Sep 17 00:00:00 2001
From: practicalswift <practicalswift@users.noreply.github.com>
Date: Fri, 21 Feb 2020 15:57:02 +0000
Subject: tests: Add fuzzing harness for Golomb-Rice coding
 (GolombRiceEncode/GolombRiceDecode)

---
 src/test/fuzz/golomb_rice.cpp | 112 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 112 insertions(+)
 create mode 100644 src/test/fuzz/golomb_rice.cpp

(limited to 'src/test/fuzz/golomb_rice.cpp')

diff --git a/src/test/fuzz/golomb_rice.cpp b/src/test/fuzz/golomb_rice.cpp
new file mode 100644
index 0000000000..3e20416116
--- /dev/null
+++ b/src/test/fuzz/golomb_rice.cpp
@@ -0,0 +1,112 @@
+// 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 <blockfilter.h>
+#include <serialize.h>
+#include <streams.h>
+#include <test/fuzz/fuzz.h>
+#include <test/fuzz/FuzzedDataProvider.h>
+#include <test/fuzz/util.h>
+#include <util/bytevectorhash.h>
+#include <util/golombrice.h>
+
+#include <algorithm>
+#include <cassert>
+#include <cstdint>
+#include <iosfwd>
+#include <unordered_set>
+#include <vector>
+
+namespace {
+uint64_t MapIntoRange(const uint64_t x, const uint64_t n)
+{
+    const uint64_t x_hi = x >> 32;
+    const uint64_t x_lo = x & 0xFFFFFFFF;
+    const uint64_t n_hi = n >> 32;
+    const uint64_t n_lo = n & 0xFFFFFFFF;
+    const uint64_t ac = x_hi * n_hi;
+    const uint64_t ad = x_hi * n_lo;
+    const uint64_t bc = x_lo * n_hi;
+    const uint64_t bd = x_lo * n_lo;
+    const uint64_t mid34 = (bd >> 32) + (bc & 0xFFFFFFFF) + (ad & 0xFFFFFFFF);
+    const uint64_t upper64 = ac + (bc >> 32) + (ad >> 32) + (mid34 >> 32);
+    return upper64;
+}
+
+uint64_t HashToRange(const std::vector<uint8_t>& element, const uint64_t f)
+{
+    const uint64_t hash = CSipHasher(0x0706050403020100ULL, 0x0F0E0D0C0B0A0908ULL)
+                              .Write(element.data(), element.size())
+                              .Finalize();
+    return MapIntoRange(hash, f);
+}
+
+std::vector<uint64_t> BuildHashedSet(const std::unordered_set<std::vector<uint8_t>, ByteVectorHash>& elements, const uint64_t f)
+{
+    std::vector<uint64_t> hashed_elements;
+    hashed_elements.reserve(elements.size());
+    for (const std::vector<uint8_t>& element : elements) {
+        hashed_elements.push_back(HashToRange(element, f));
+    }
+    std::sort(hashed_elements.begin(), hashed_elements.end());
+    return hashed_elements;
+}
+} // namespace
+
+void test_one_input(const std::vector<uint8_t>& buffer)
+{
+    FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
+    std::vector<uint8_t> golomb_rice_data;
+    std::vector<uint64_t> encoded_deltas;
+    {
+        std::unordered_set<std::vector<uint8_t>, ByteVectorHash> elements;
+        const int n = fuzzed_data_provider.ConsumeIntegralInRange<int>(0, 512);
+        for (int i = 0; i < n; ++i) {
+            elements.insert(ConsumeRandomLengthByteVector(fuzzed_data_provider, 16));
+        }
+        CVectorWriter stream(SER_NETWORK, 0, golomb_rice_data, 0);
+        WriteCompactSize(stream, static_cast<uint32_t>(elements.size()));
+        BitStreamWriter<CVectorWriter> bitwriter(stream);
+        if (!elements.empty()) {
+            uint64_t last_value = 0;
+            for (const uint64_t value : BuildHashedSet(elements, static_cast<uint64_t>(elements.size()) * static_cast<uint64_t>(BASIC_FILTER_M))) {
+                const uint64_t delta = value - last_value;
+                encoded_deltas.push_back(delta);
+                GolombRiceEncode(bitwriter, BASIC_FILTER_P, delta);
+                last_value = value;
+            }
+        }
+        bitwriter.Flush();
+    }
+
+    std::vector<uint64_t> decoded_deltas;
+    {
+        VectorReader stream{SER_NETWORK, 0, golomb_rice_data, 0};
+        BitStreamReader<VectorReader> bitreader(stream);
+        const uint32_t n = static_cast<uint32_t>(ReadCompactSize(stream));
+        for (uint32_t i = 0; i < n; ++i) {
+            decoded_deltas.push_back(GolombRiceDecode(bitreader, BASIC_FILTER_P));
+        }
+    }
+
+    assert(encoded_deltas == decoded_deltas);
+
+    {
+        const std::vector<uint8_t> random_bytes = ConsumeRandomLengthByteVector(fuzzed_data_provider, 1024);
+        VectorReader stream{SER_NETWORK, 0, random_bytes, 0};
+        uint32_t n;
+        try {
+            n = static_cast<uint32_t>(ReadCompactSize(stream));
+        } catch (const std::ios_base::failure&) {
+            return;
+        }
+        BitStreamReader<VectorReader> bitreader(stream);
+        for (uint32_t i = 0; i < std::min<uint32_t>(n, 1024); ++i) {
+            try {
+                (void)GolombRiceDecode(bitreader, BASIC_FILTER_P);
+            } catch (const std::ios_base::failure&) {
+            }
+        }
+    }
+}
-- 
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