Merge #19222: tests: Add fuzzing harness for BanMan

97846d7f5b47ef77469b9f961db77f770e8bcc0f tests: Add fuzzing harness for BanMan (practicalswift)
deba199f1c88c2e5f754b0a4ec43b9ef28de8352 tests: Add ConsumeSubNet(...). Move and increase coverage in ConsumeNetAddr(...). (practicalswift)

Pull request description:

  Add fuzzing harness for `BanMan`.

  See [`doc/fuzzing.md`](https://github.com/bitcoin/bitcoin/blob/master/doc/fuzzing.md) for information on how to fuzz Bitcoin Core. Don't forget to contribute any coverage increasing inputs you find to the [Bitcoin Core fuzzing corpus repo](https://github.com/bitcoin-core/qa-assets).

  Happy fuzzing :)

Top commit has no ACKs.

Tree-SHA512: f4126c15bbb77638833367d73f58193c8f05d16bed0b1d6c33b39387d5b610ff34af78cd721adb51778062ce3ac5e79756d1c3895ef54c6c80c61dcf056e94ff

3 files changed, 125 insertions, 29 deletions

diff --git a/src/test/fuzz/banman.cpp b/src/test/fuzz/banman.cpp
new file mode 100644
index 0000000000..fc4a1d9261
--- /dev/null
+++ b/src/test/fuzz/banman.cpp
@@ -0,0 +1,88 @@
+// 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 <banman.h>
+#include <fs.h>
+#include <netaddress.h>
+#include <test/fuzz/FuzzedDataProvider.h>
+#include <test/fuzz/fuzz.h>
+#include <test/fuzz/util.h>
+#include <util/system.h>
+
+#include <cstdint>
+#include <limits>
+#include <string>
+#include <vector>
+
+namespace {
+int64_t ConsumeBanTimeOffset(FuzzedDataProvider& fuzzed_data_provider) noexcept
+{
+    // Avoid signed integer overflow by capping to int32_t max:
+    // banman.cpp:137:73: runtime error: signed integer overflow: 1591700817 + 9223372036854775807 cannot be represented in type 'long'
+    return fuzzed_data_provider.ConsumeIntegralInRange<int64_t>(std::numeric_limits<int64_t>::min(), std::numeric_limits<int32_t>::max());
+}
+} // namespace
+
+void initialize()
+{
+    InitializeFuzzingContext();
+}
+
+void test_one_input(const std::vector<uint8_t>& buffer)
+{
+    FuzzedDataProvider fuzzed_data_provider{buffer.data(), buffer.size()};
+    const fs::path banlist_file = GetDataDir() / "fuzzed_banlist.dat";
+    fs::remove(banlist_file);
+    {
+        BanMan ban_man{banlist_file, nullptr, ConsumeBanTimeOffset(fuzzed_data_provider)};
+        while (fuzzed_data_provider.ConsumeBool()) {
+            switch (fuzzed_data_provider.ConsumeIntegralInRange<int>(0, 11)) {
+            case 0: {
+                ban_man.Ban(ConsumeNetAddr(fuzzed_data_provider),
+                    ConsumeBanTimeOffset(fuzzed_data_provider), fuzzed_data_provider.ConsumeBool());
+                break;
+            }
+            case 1: {
+                ban_man.Ban(ConsumeSubNet(fuzzed_data_provider),
+                    ConsumeBanTimeOffset(fuzzed_data_provider), fuzzed_data_provider.ConsumeBool());
+                break;
+            }
+            case 2: {
+                ban_man.ClearBanned();
+                break;
+            }
+            case 4: {
+                ban_man.IsBanned(ConsumeNetAddr(fuzzed_data_provider));
+                break;
+            }
+            case 5: {
+                ban_man.IsBanned(ConsumeSubNet(fuzzed_data_provider));
+                break;
+            }
+            case 6: {
+                ban_man.Unban(ConsumeNetAddr(fuzzed_data_provider));
+                break;
+            }
+            case 7: {
+                ban_man.Unban(ConsumeSubNet(fuzzed_data_provider));
+                break;
+            }
+            case 8: {
+                banmap_t banmap;
+                ban_man.GetBanned(banmap);
+                break;
+            }
+            case 9: {
+                ban_man.DumpBanlist();
+                break;
+            }
+            case 11: {
+                ban_man.Discourage(ConsumeNetAddr(fuzzed_data_provider));
+                break;
+            }
+            }
+        }
+    }
+    fs::remove(banlist_file);
+}
diff --git a/src/test/fuzz/netaddress.cpp b/src/test/fuzz/netaddress.cpp
index d8d53566c7..2901c704f6 100644
--- a/src/test/fuzz/netaddress.cpp
+++ b/src/test/fuzz/netaddress.cpp
@@ -5,41 +5,13 @@
 #include <netaddress.h>
 #include <test/fuzz/FuzzedDataProvider.h>
 #include <test/fuzz/fuzz.h>
+#include <test/fuzz/util.h>
 
 #include <cassert>
 #include <cstdint>
 #include <netinet/in.h>
 #include <vector>
 
-namespace {
-CNetAddr ConsumeNetAddr(FuzzedDataProvider& fuzzed_data_provider) noexcept
-{
-    const Network network = fuzzed_data_provider.PickValueInArray({Network::NET_IPV4, Network::NET_IPV6, Network::NET_INTERNAL, Network::NET_ONION});
-    if (network == Network::NET_IPV4) {
-        const in_addr v4_addr = {
-            .s_addr = fuzzed_data_provider.ConsumeIntegral<uint32_t>()};
-        return CNetAddr{v4_addr};
-    } else if (network == Network::NET_IPV6) {
-        if (fuzzed_data_provider.remaining_bytes() < 16) {
-            return CNetAddr{};
-        }
-        in6_addr v6_addr = {};
-        memcpy(v6_addr.s6_addr, fuzzed_data_provider.ConsumeBytes<uint8_t>(16).data(), 16);
-        return CNetAddr{v6_addr, fuzzed_data_provider.ConsumeIntegral<uint32_t>()};
-    } else if (network == Network::NET_INTERNAL) {
-        CNetAddr net_addr;
-        net_addr.SetInternal(fuzzed_data_provider.ConsumeBytesAsString(32));
-        return net_addr;
-    } else if (network == Network::NET_ONION) {
-        CNetAddr net_addr;
-        net_addr.SetSpecial(fuzzed_data_provider.ConsumeBytesAsString(32));
-        return net_addr;
-    } else {
-        assert(false);
-    }
-}
-}; // namespace
-
 void test_one_input(const std::vector<uint8_t>& buffer)
 {
     FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
diff --git a/src/test/fuzz/util.h b/src/test/fuzz/util.h
index 1c1b2cd254..8cf91ef940 100644
--- a/src/test/fuzz/util.h
+++ b/src/test/fuzz/util.h
@@ -8,8 +8,11 @@
 #include <amount.h>
 #include <arith_uint256.h>
 #include <attributes.h>
+#include <chainparamsbase.h>
 #include <coins.h>
 #include <consensus/consensus.h>
+#include <netaddress.h>
+#include <netbase.h>
 #include <primitives/transaction.h>
 #include <script/script.h>
 #include <script/standard.h>
@@ -17,6 +20,7 @@
 #include <streams.h>
 #include <test/fuzz/FuzzedDataProvider.h>
 #include <test/fuzz/fuzz.h>
+#include <test/util/setup_common.h>
 #include <txmempool.h>
 #include <uint256.h>
 #include <version.h>
@@ -228,4 +232,36 @@ NODISCARD inline std::vector<uint8_t> ConsumeFixedLengthByteVector(FuzzedDataPro
     return result;
 }
 
+CNetAddr ConsumeNetAddr(FuzzedDataProvider& fuzzed_data_provider) noexcept
+{
+    const Network network = fuzzed_data_provider.PickValueInArray({Network::NET_IPV4, Network::NET_IPV6, Network::NET_INTERNAL, Network::NET_ONION});
+    CNetAddr net_addr;
+    if (network == Network::NET_IPV4) {
+        const in_addr v4_addr = {
+            .s_addr = fuzzed_data_provider.ConsumeIntegral<uint32_t>()};
+        net_addr = CNetAddr{v4_addr};
+    } else if (network == Network::NET_IPV6) {
+        if (fuzzed_data_provider.remaining_bytes() >= 16) {
+            in6_addr v6_addr = {};
+            memcpy(v6_addr.s6_addr, fuzzed_data_provider.ConsumeBytes<uint8_t>(16).data(), 16);
+            net_addr = CNetAddr{v6_addr, fuzzed_data_provider.ConsumeIntegral<uint32_t>()};
+        }
+    } else if (network == Network::NET_INTERNAL) {
+        net_addr.SetInternal(fuzzed_data_provider.ConsumeBytesAsString(32));
+    } else if (network == Network::NET_ONION) {
+        net_addr.SetSpecial(fuzzed_data_provider.ConsumeBytesAsString(32));
+    }
+    return net_addr;
+}
+
+CSubNet ConsumeSubNet(FuzzedDataProvider& fuzzed_data_provider) noexcept
+{
+    return {ConsumeNetAddr(fuzzed_data_provider), fuzzed_data_provider.ConsumeIntegral<int32_t>()};
+}
+
+void InitializeFuzzingContext(const std::string& chain_name = CBaseChainParams::REGTEST)
+{
+    static const BasicTestingSetup basic_testing_setup{chain_name, {"-nodebuglogfile"}};
+}
+
 #endif // BITCOIN_TEST_FUZZ_UTIL_H