fuzz: add script parser harness (#5)

1 files changed, 59 insertions, 0 deletions

diff --git a/src/fuzz_script.cpp b/src/fuzz_script.cpp
new file mode 100644
index 0000000..28c84f6
--- /dev/null
+++ b/src/fuzz_script.cpp
@@ -0,0 +1,59 @@
+// Copyright (c) 2026 Bitflash developers
+// Distributed under the MIT/X11 software license.
+//
+// libFuzzer harness for raw script parsing and evaluation. It keeps the
+// target deliberately small: arbitrary bytes become one CScript, then the
+// parser, standard-script extractors and EvalScript all see that same input.
+
+#include "headers_core.h"
+
+#include <stdint.h>
+#include <stddef.h>
+
+// Stand-ins normally supplied by the GUI/headless entry objects.
+map<string,string> mapAddressBook;
+bool gPoolServerRunning = false;
+void MainFrameRepaint() {}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size)
+{
+    if (size < 1 || size > 4096)
+        return 0;
+
+    try
+    {
+        int nHashType = data[0];
+        const unsigned char* pbegin = data + 1;
+        const unsigned char* pend = data + size;
+        CScript script(pbegin, pend);
+
+        CScript::const_iterator pc = script.begin();
+        opcodetype opcode;
+        vector<unsigned char> vchPush;
+        while (pc < script.end())
+        {
+            if (!script.GetOp(pc, opcode, vchPush))
+                break;
+        }
+
+        script.GetSigOpCount();
+        script.ToString();
+
+        vector<unsigned char> vchPubKey;
+        ExtractPubKey(script, false, vchPubKey);
+        uint160 hash160;
+        ExtractHash160(script, hash160);
+
+        CTransaction tx;
+        tx.vin.push_back(CTxIn(COutPoint(), CScript()));
+        tx.vout.push_back(CTxOut(0, CScript()));
+
+        vector<vector<unsigned char> > stack;
+        EvalScript(script, tx, 0, nHashType, &stack);
+    }
+    catch (...)
+    {
+    }
+
+    return 0;
+}