contrib/fuzz/manifest.cc
author Pierre-Yves David <pierre-yves.david@octobus.net>
Mon, 07 Jun 2021 21:09:31 +0200
changeset 47423 9ea525216edb
parent 45006 0ff59434af72
permissions -rw-r--r--
copyfiles: deal with existing file when hardlinking If the hardlinking fails, we fallback to `shutil.copy`, but do not consider future hardlinking doomed. This is a slight improvement from the current situation, we still avoid hardliking in a case we might be able to do it. However this does not have an impact of the rest of the operation. (This is an opportunity improvement while looking at something next to that.) Differential Revision: https://phab.mercurial-scm.org/D10841

#include <Python.h>
#include <assert.h>
#include <stdlib.h>
#include <unistd.h>

#include "FuzzedDataProvider.h"
#include "pyutil.h"

#include <string>

extern "C" {

static PYCODETYPE *code;

extern "C" int LLVMFuzzerInitialize(int *argc, char ***argv)
{
	contrib::initpy(*argv[0]);
	code = (PYCODETYPE *)Py_CompileString(R"py(
try:
  lm = parsers.lazymanifest(mdata)
  # iterate the whole thing, which causes the code to fully parse
  # every line in the manifest
  for e, _, _ in lm.iterentries():
      # also exercise __getitem__ et al
      lm[e]
      e in lm
      (e + 'nope') in lm
  lm[b'xyzzy'] = (b'\0' * nlen, 'x')
  # do an insert, text should change
  assert lm.text() != mdata, "insert should change text and didn't: %r %r" % (lm.text(), mdata)
  cloned = lm.filtercopy(lambda x: x != 'xyzzy')
  assert cloned.text() == mdata, 'cloned text should equal mdata'
  cloned.diff(lm)
  del lm[b'xyzzy']
  cloned.diff(lm)
  # should be back to the same
  assert lm.text() == mdata, "delete should have restored text but didn't: %r %r" % (lm.text(), mdata)
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;
	}
	FuzzedDataProvider provider(Data, Size);
	Py_ssize_t nodelength = provider.ConsumeBool() ? 20 : 32;
	PyObject *nlen = PyLong_FromSsize_t(nodelength);
	PyObject *mtext =
	    PyBytes_FromStringAndSize((const char *)Data, (Py_ssize_t)Size);
	PyObject *locals = PyDict_New();
	PyDict_SetItemString(locals, "mdata", mtext);
	PyDict_SetItemString(locals, "nlen", nlen);
	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.
}
}