diff contrib/fuzz/dirs.cc @ 43150:7ff40418c6bf

fuzz: new fuzzer for dirs.c

This found a six-year-old bug immediately, and then I put it through a
few CPU-days of time before sending it.

Differential Revision: https://phab.mercurial-scm.org/D7031

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/contrib/fuzz/dirs.cc	Wed Oct 09 20:48:12 2019 -0700
@@ -0,0 +1,56 @@
+#include <Python.h>
+#include <assert.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "pyutil.h"
+
+#include <string>
+
+extern "C" {
+
+static PyCodeObject *code;
+
+extern "C" int LLVMFuzzerInitialize(int *argc, char ***argv)
+{
+	contrib::initpy(*argv[0]);
+	code = (PyCodeObject *)Py_CompileString(R"py(
+from parsers import dirs
+try:
+  files = mdata.split('\n')
+  d = dirs(files)
+  list(d)
+  'a' in d
+  if files:
+    files[0] in d
+except Exception as e:
+  pass
+  # uncomment this print if you're editing this Python code
+  # to debug failures.
+  # print e
+)py",
+	                                        "fuzzer", Py_file_input);
+	return 0;
+}
+
+int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size)
+{
+	// Don't allow fuzzer inputs larger than 100k, since we'll just bog
+	// down and not accomplish much.
+	if (Size > 100000) {
+		return 0;
+	}
+	PyObject *mtext =
+	    PyBytes_FromStringAndSize((const char *)Data, (Py_ssize_t)Size);
+	PyObject *locals = PyDict_New();
+	PyDict_SetItemString(locals, "mdata", mtext);
+	PyObject *res = PyEval_EvalCode(code, contrib::pyglobals(), locals);
+	if (!res) {
+		PyErr_Print();
+	}
+	Py_XDECREF(res);
+	Py_DECREF(locals);
+	Py_DECREF(mtext);
+	return 0; // Non-zero return values are reserved for future use.
+}
+}