fuzz: restrict manifest input size
Again, let's keep the fuzzer from getting excited about huge inputs.
Differential Revision: https://phab.mercurial-scm.org/D5642
#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 lazymanifest
try:
lm = lazymanifest(mdata)
# iterate the whole thing, which causes the code to fully parse
# every line in the manifest
list(lm.iterentries())
lm[b'xyzzy'] = (b'\0' * 20, 'x')
# do an insert, text should change
assert lm.text() != mdata, "insert should change text and didn't: %r %r" % (lm.text(), mdata)
del lm[b'xyzzy']
# 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;
}
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.
}
}