Merge #17771: tests: Add fuzzing harness for V1TransportDeserializer (P2P transport)

2f63ffd15caeb79867e56c8cedbe2c702952db9e tests: Add fuzzing harness for V1TransportDeserializer (P2P transport) (practicalswift)

Pull request description:

  Add fuzzing harness for `V1TransportDeserializer` (P2P transport).

  **Testing this PR**

  Run:

  ```
  $ make distclean
  $ ./autogen.sh
  $ CC=clang CXX=clang++ ./configure --enable-fuzz \
        --with-sanitizers=address,fuzzer,undefined
  $ make
  $ src/test/fuzz/p2p_transport_deserializer
  …
  ```

ACKs for top commit:
  MarcoFalke:
    ACK 2f63ffd15caeb79867e56c8cedbe2c702952db9e

Tree-SHA512: 8507d4a0414d16f1b8cc9649e3e638f74071dddc990d7e5d7e6faf77697f50bdaf133e49e2371edd29068a069a074469ef53148c6bfc9950510460b81d87646a

1 files changed, 47 insertions, 0 deletions

diff --git a/src/test/fuzz/p2p_transport_deserializer.cpp b/src/test/fuzz/p2p_transport_deserializer.cpp
new file mode 100644
index 0000000000..57393fed45
--- /dev/null
+++ b/src/test/fuzz/p2p_transport_deserializer.cpp
@@ -0,0 +1,47 @@
+// Copyright (c) 2019 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 <chainparams.h>
+#include <net.h>
+#include <protocol.h>
+#include <test/fuzz/fuzz.h>
+
+#include <cassert>
+#include <cstdint>
+#include <limits>
+#include <vector>
+
+void initialize()
+{
+    SelectParams(CBaseChainParams::REGTEST);
+}
+
+void test_one_input(const std::vector<uint8_t>& buffer)
+{
+    V1TransportDeserializer deserializer{Params().MessageStart(), SER_NETWORK, INIT_PROTO_VERSION};
+    const char* pch = (const char*)buffer.data();
+    size_t n_bytes = buffer.size();
+    while (n_bytes > 0) {
+        const int handled = deserializer.Read(pch, n_bytes);
+        if (handled < 0) {
+            break;
+        }
+        pch += handled;
+        n_bytes -= handled;
+        if (deserializer.Complete()) {
+            const int64_t m_time = std::numeric_limits<int64_t>::max();
+            const CNetMessage msg = deserializer.GetMessage(Params().MessageStart(), m_time);
+            assert(msg.m_command.size() <= CMessageHeader::COMMAND_SIZE);
+            assert(msg.m_raw_message_size <= buffer.size());
+            assert(msg.m_raw_message_size == CMessageHeader::HEADER_SIZE + msg.m_message_size);
+            assert(msg.m_time == m_time);
+            if (msg.m_valid_header) {
+                assert(msg.m_valid_netmagic);
+            }
+            if (!msg.m_valid_netmagic) {
+                assert(!msg.m_valid_header);
+            }
+        }
+    }
+}