1 files changed, 71 insertions, 0 deletions
diff --git a/src/test/fuzz/netbase_dns_lookup.cpp b/src/test/fuzz/netbase_dns_lookup.cpp
new file mode 100644
index 0000000000..cf2fa33744
--- /dev/null
+++ b/src/test/fuzz/netbase_dns_lookup.cpp
@@ -0,0 +1,71 @@
+// Copyright (c) 2021 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 <netaddress.h>
+#include <netbase.h>
+#include <test/fuzz/FuzzedDataProvider.h>
+#include <test/fuzz/fuzz.h>
+#include <test/fuzz/util.h>
+
+#include <cstdint>
+#include <string>
+#include <vector>
+
+FUZZ_TARGET(netbase_dns_lookup)
+{
+    FuzzedDataProvider fuzzed_data_provider{buffer.data(), buffer.size()};
+    const std::string name = fuzzed_data_provider.ConsumeRandomLengthString(512);
+    const unsigned int max_results = fuzzed_data_provider.ConsumeIntegral<unsigned int>();
+    const bool allow_lookup = fuzzed_data_provider.ConsumeBool();
+    const uint16_t default_port = fuzzed_data_provider.ConsumeIntegral<uint16_t>();
+
+    auto fuzzed_dns_lookup_function = [&](const std::string&, bool) {
+        std::vector<CNetAddr> resolved_addresses;
+        while (fuzzed_data_provider.ConsumeBool()) {
+            resolved_addresses.push_back(ConsumeNetAddr(fuzzed_data_provider));
+        }
+        return resolved_addresses;
+    };
+
+    {
+        std::vector<CNetAddr> resolved_addresses;
+        if (LookupHost(name, resolved_addresses, max_results, allow_lookup, fuzzed_dns_lookup_function)) {
+            for (const CNetAddr& resolved_address : resolved_addresses) {
+                assert(!resolved_address.IsInternal());
+            }
+        }
+        assert(resolved_addresses.size() <= max_results || max_results == 0);
+    }
+    {
+        CNetAddr resolved_address;
+        if (LookupHost(name, resolved_address, allow_lookup, fuzzed_dns_lookup_function)) {
+            assert(!resolved_address.IsInternal());
+        }
+    }
+    {
+        std::vector<CService> resolved_services;
+        if (Lookup(name, resolved_services, default_port, allow_lookup, max_results, fuzzed_dns_lookup_function)) {
+            for (const CNetAddr& resolved_service : resolved_services) {
+                assert(!resolved_service.IsInternal());
+            }
+        }
+        assert(resolved_services.size() <= max_results || max_results == 0);
+    }
+    {
+        CService resolved_service;
+        if (Lookup(name, resolved_service, default_port, allow_lookup, fuzzed_dns_lookup_function)) {
+            assert(!resolved_service.IsInternal());
+        }
+    }
+    {
+        CService resolved_service = LookupNumeric(name, default_port, fuzzed_dns_lookup_function);
+        assert(!resolved_service.IsInternal());
+    }
+    {
+        CSubNet resolved_subnet;
+        if (LookupSubNet(name, resolved_subnet, fuzzed_dns_lookup_function)) {
+            assert(resolved_subnet.IsValid());
+        }
+    }
+}