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AFLplusplus/src/afl-fuzz-python.c
Dominik Maier 1f34b9f8e1 added python mutator, documentation
2020-12-04 14:26:48 +01:00

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/*
american fuzzy lop++ - python extension routines
------------------------------------------------
Originally written by Michal Zalewski
Now maintained by Marc Heuse <mh@mh-sec.de>,
Heiko Eißfeldt <heiko.eissfeldt@hexco.de> and
Andrea Fioraldi <andreafioraldi@gmail.com>
Copyright 2016, 2017 Google Inc. All rights reserved.
Copyright 2019-2020 AFLplusplus Project. All rights reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at:
http://www.apache.org/licenses/LICENSE-2.0
This is the real deal: the program takes an instrumented binary and
attempts a variety of basic fuzzing tricks, paying close attention to
how they affect the execution path.
*/
#include "afl-fuzz.h"
/* Python stuff */
#ifdef USE_PYTHON
static void *unsupported(afl_state_t *afl, unsigned int seed) {
(void)afl;
(void)seed;
FATAL("Python Mutator cannot be called twice yet");
return NULL;
}
/* sorry for this makro...
it just fills in `&py_mutator->something_buf, &py_mutator->something_size`. */
#define BUF_PARAMS(name) (void **)&((py_mutator_t *)py_mutator)->name##_buf
static size_t fuzz_py(void *py_mutator, u8 *buf, size_t buf_size, u8 **out_buf,
u8 *add_buf, size_t add_buf_size, size_t max_size) {
size_t mutated_size;
PyObject *py_args, *py_value;
py_args = PyTuple_New(3);
py_mutator_t *py = (py_mutator_t *)py_mutator;
/* buf */
py_value = PyByteArray_FromStringAndSize(buf, buf_size);
if (!py_value) {
Py_DECREF(py_args);
FATAL("Failed to convert arguments");
}
PyTuple_SetItem(py_args, 0, py_value);
/* add_buf */
py_value = PyByteArray_FromStringAndSize(add_buf, add_buf_size);
if (!py_value) {
Py_DECREF(py_args);
FATAL("Failed to convert arguments");
}
PyTuple_SetItem(py_args, 1, py_value);
/* max_size */
#if PY_MAJOR_VERSION >= 3
py_value = PyLong_FromLong(max_size);
#else
py_value = PyInt_FromLong(max_size);
#endif
if (!py_value) {
Py_DECREF(py_args);
FATAL("Failed to convert arguments");
}
PyTuple_SetItem(py_args, 2, py_value);
py_value = PyObject_CallObject(py->py_functions[PY_FUNC_FUZZ], py_args);
Py_DECREF(py_args);
if (py_value != NULL) {
mutated_size = PyByteArray_Size(py_value);
*out_buf = afl_realloc(BUF_PARAMS(fuzz), mutated_size);
if (unlikely(!*out_buf)) { PFATAL("alloc"); }
memcpy(*out_buf, PyByteArray_AsString(py_value), mutated_size);
Py_DECREF(py_value);
return mutated_size;
} else {
PyErr_Print();
FATAL("python custom fuzz: call failed");
}
}
static const char *custom_describe_py(void * py_mutator,
size_t max_description_len) {
PyObject *py_args, *py_value;
py_args = PyTuple_New(1);
PyLong_FromSize_t(max_description_len);
/* add_buf */
py_value = PyLong_FromSize_t(max_description_len);
if (!py_value) {
Py_DECREF(py_args);
FATAL("Failed to convert arguments");
}
PyTuple_SetItem(py_args, 0, py_value);
py_value = PyObject_CallObject(
((py_mutator_t *)py_mutator)->py_functions[PY_FUNC_DESCRIBE], py_args);
Py_DECREF(py_args);
if (py_value != NULL) { return PyBytes_AsString(py_value); }
return NULL;
}
static py_mutator_t *init_py_module(afl_state_t *afl, u8 *module_name) {
(void)afl;
if (!module_name) { return NULL; }
py_mutator_t *py = calloc(1, sizeof(py_mutator_t));
if (!py) { PFATAL("Could not allocate memory for python mutator!"); }
Py_Initialize();
#if PY_MAJOR_VERSION >= 3
PyObject *py_name = PyUnicode_FromString(module_name);
#else
PyObject *py_name = PyString_FromString(module_name);
#endif
py->py_module = PyImport_Import(py_name);
Py_DECREF(py_name);
PyObject * py_module = py->py_module;
PyObject **py_functions = py->py_functions;
// initialize the post process buffer; ensures it's always valid
PyObject *unused_bytes = PyByteArray_FromStringAndSize("OHAI", 4);
if (!unused_bytes) { FATAL("allocation failed!"); }
if (PyObject_GetBuffer(unused_bytes, &py->post_process_buf, PyBUF_SIMPLE) ==
-1) {
FATAL("buffer initialization failed");
}
Py_DECREF(unused_bytes);
if (py_module != NULL) {
u8 py_notrim = 0, py_idx;
/* init, required */
py_functions[PY_FUNC_INIT] = PyObject_GetAttrString(py_module, "init");
if (!py_functions[PY_FUNC_INIT])
FATAL("init function not found in python module");
py_functions[PY_FUNC_FUZZ] = PyObject_GetAttrString(py_module, "fuzz");
if (!py_functions[PY_FUNC_FUZZ])
py_functions[PY_FUNC_FUZZ] = PyObject_GetAttrString(py_module, "mutate");
py_functions[PY_FUNC_DESCRIBE] =
PyObject_GetAttrString(py_module, "describe");
py_functions[PY_FUNC_FUZZ_COUNT] =
PyObject_GetAttrString(py_module, "fuzz_count");
if (!py_functions[PY_FUNC_FUZZ])
WARNF("fuzz function not found in python module");
py_functions[PY_FUNC_POST_PROCESS] =
PyObject_GetAttrString(py_module, "post_process");
py_functions[PY_FUNC_INIT_TRIM] =
PyObject_GetAttrString(py_module, "init_trim");
py_functions[PY_FUNC_POST_TRIM] =
PyObject_GetAttrString(py_module, "post_trim");
py_functions[PY_FUNC_TRIM] = PyObject_GetAttrString(py_module, "trim");
py_functions[PY_FUNC_HAVOC_MUTATION] =
PyObject_GetAttrString(py_module, "havoc_mutation");
py_functions[PY_FUNC_HAVOC_MUTATION_PROBABILITY] =
PyObject_GetAttrString(py_module, "havoc_mutation_probability");
py_functions[PY_FUNC_QUEUE_GET] =
PyObject_GetAttrString(py_module, "queue_get");
py_functions[PY_FUNC_QUEUE_NEW_ENTRY] =
PyObject_GetAttrString(py_module, "queue_new_entry");
py_functions[PY_FUNC_INTROSPECTION] =
PyObject_GetAttrString(py_module, "introspection");
py_functions[PY_FUNC_DEINIT] = PyObject_GetAttrString(py_module, "deinit");
if (!py_functions[PY_FUNC_DEINIT])
FATAL("deinit function not found in python module");
for (py_idx = 0; py_idx < PY_FUNC_COUNT; ++py_idx) {
if (!py_functions[py_idx] || !PyCallable_Check(py_functions[py_idx])) {
if (py_idx >= PY_FUNC_INIT_TRIM && py_idx <= PY_FUNC_TRIM) {
// Implementing the trim API is optional for now
if (PyErr_Occurred()) { PyErr_Print(); }
py_notrim = 1;
} else if (py_idx >= PY_OPTIONAL) {
// Only _init and _deinit are not optional currently
if (PyErr_Occurred()) { PyErr_Print(); }
} else {
fprintf(stderr,
"Cannot find/call function with index %d in external "
"Python module.\n",
py_idx);
return NULL;
}
}
}
if (py_notrim) {
py_functions[PY_FUNC_INIT_TRIM] = NULL;
py_functions[PY_FUNC_POST_TRIM] = NULL;
py_functions[PY_FUNC_TRIM] = NULL;
WARNF(
"Python module does not implement trim API, standard trimming will "
"be used.");
}
} else {
PyErr_Print();
fprintf(stderr, "Failed to load \"%s\"\n", module_name);
free(py);
return NULL;
}
return py;
}
void finalize_py_module(void *py_mutator) {
py_mutator_t *py = (py_mutator_t *)py_mutator;
if (py->py_module != NULL) {
deinit_py(py_mutator);
u32 i;
for (i = 0; i < PY_FUNC_COUNT; ++i) {
Py_XDECREF(py->py_functions[i]);
}
Py_DECREF(py->py_module);
}
Py_Finalize();
}
static void init_py(afl_state_t *afl, py_mutator_t *py_mutator,
unsigned int seed) {
(void)afl;
PyObject *py_args, *py_value;
/* Provide the init function a seed for the Python RNG */
py_args = PyTuple_New(1);
#if PY_MAJOR_VERSION >= 3
py_value = PyLong_FromLong(seed);
#else
py_value = PyInt_FromLong(seed);
#endif
if (!py_value) {
Py_DECREF(py_args);
FATAL("Cannot convert argument in python init.");
}
PyTuple_SetItem(py_args, 0, py_value);
py_value =
PyObject_CallObject(py_mutator->py_functions[PY_FUNC_INIT], py_args);
Py_DECREF(py_args);
if (py_value == NULL) {
PyErr_Print();
fprintf(stderr, "Call failed\n");
FATAL("Custom py mutator INIT failed.");
}
}
void deinit_py(void *py_mutator) {
PyObject *py_args, *py_value;
py_args = PyTuple_New(0);
py_value = PyObject_CallObject(
((py_mutator_t *)py_mutator)->py_functions[PY_FUNC_DEINIT], py_args);
Py_DECREF(py_args);
if (py_value != NULL) {
Py_DECREF(py_value);
} else {
PyErr_Print();
FATAL("Call failed");
}
}
struct custom_mutator *load_custom_mutator_py(afl_state_t *afl,
char * module_name) {
struct custom_mutator *mutator;
mutator = ck_alloc(sizeof(struct custom_mutator));
mutator->name = module_name;
ACTF("Loading Python mutator library from '%s'...", module_name);
py_mutator_t *py_mutator;
py_mutator = init_py_module(afl, module_name);
mutator->data = py_mutator;
if (!py_mutator) { FATAL("Failed to load python mutator."); }
PyObject **py_functions = py_mutator->py_functions;
if (py_functions[PY_FUNC_INIT]) { mutator->afl_custom_init = unsupported; }
if (py_functions[PY_FUNC_DEINIT]) { mutator->afl_custom_deinit = deinit_py; }
if (py_functions[PY_FUNC_FUZZ]) { mutator->afl_custom_fuzz = fuzz_py; }
if (py_functions[PY_FUNC_DESCRIBE]) {
mutator->afl_custom_describe = custom_describe_py;
}
if (py_functions[PY_FUNC_POST_PROCESS]) {
mutator->afl_custom_post_process = post_process_py;
}
if (py_functions[PY_FUNC_INIT_TRIM]) {
mutator->afl_custom_init_trim = init_trim_py;
}
if (py_functions[PY_FUNC_FUZZ_COUNT]) {
mutator->afl_custom_fuzz_count = fuzz_count_py;
}
if (py_functions[PY_FUNC_POST_TRIM]) {
mutator->afl_custom_post_trim = post_trim_py;
}
if (py_functions[PY_FUNC_TRIM]) { mutator->afl_custom_trim = trim_py; }
if (py_functions[PY_FUNC_HAVOC_MUTATION]) {
mutator->afl_custom_havoc_mutation = havoc_mutation_py;
}
if (py_functions[PY_FUNC_HAVOC_MUTATION_PROBABILITY]) {
mutator->afl_custom_havoc_mutation_probability =
havoc_mutation_probability_py;
}
if (py_functions[PY_FUNC_QUEUE_GET]) {
mutator->afl_custom_queue_get = queue_get_py;
}
if (py_functions[PY_FUNC_QUEUE_NEW_ENTRY]) {
mutator->afl_custom_queue_new_entry = queue_new_entry_py;
}
#ifdef INTROSPECTION
if (py_functions[PY_FUNC_INTROSPECTION]) {
mutator->afl_custom_introspection = introspection_py;
}
#endif
OKF("Python mutator '%s' installed successfully.", module_name);
/* Initialize the custom mutator */
init_py(afl, py_mutator, rand_below(afl, 0xFFFFFFFF));
return mutator;
}
size_t post_process_py(void *py_mutator, u8 *buf, size_t buf_size,
u8 **out_buf) {
PyObject * py_args, *py_value;
py_mutator_t *py = (py_mutator_t *)py_mutator;
// buffer returned previously must be released; initialized during init
// so we don't need to do comparisons
PyBuffer_Release(&py->post_process_buf);
py_args = PyTuple_New(1);
py_value = PyByteArray_FromStringAndSize(buf, buf_size);
if (!py_value) {
Py_DECREF(py_args);
FATAL("Failed to convert arguments in custom post_process");
}
PyTuple_SetItem(py_args, 0, py_value);
py_value = PyObject_CallObject(
((py_mutator_t *)py_mutator)->py_functions[PY_FUNC_POST_PROCESS],
py_args);
Py_DECREF(py_args);
if (py_value != NULL) {
if (PyObject_GetBuffer(py_value, &py->post_process_buf, PyBUF_SIMPLE) ==
-1) {
PyErr_Print();
FATAL(
"Python custom mutator: post_process call return value not a "
"bytes-like object");
}
Py_DECREF(py_value);
*out_buf = (u8 *)py->post_process_buf.buf;
return py->post_process_buf.len;
} else {
PyErr_Print();
FATAL("Python custom mutator: post_process call failed.");
}
}
s32 init_trim_py(void *py_mutator, u8 *buf, size_t buf_size) {
PyObject *py_args, *py_value;
py_args = PyTuple_New(1);
py_value = PyByteArray_FromStringAndSize(buf, buf_size);
if (!py_value) {
Py_DECREF(py_args);
FATAL("Failed to convert arguments");
}
PyTuple_SetItem(py_args, 0, py_value);
py_value = PyObject_CallObject(
((py_mutator_t *)py_mutator)->py_functions[PY_FUNC_INIT_TRIM], py_args);
Py_DECREF(py_args);
if (py_value != NULL) {
#if PY_MAJOR_VERSION >= 3
u32 retcnt = (u32)PyLong_AsLong(py_value);
#else
u32 retcnt = PyInt_AsLong(py_value);
#endif
Py_DECREF(py_value);
return retcnt;
} else {
PyErr_Print();
FATAL("Call failed");
}
}
u32 fuzz_count_py(void *py_mutator, const u8 *buf, size_t buf_size) {
PyObject *py_args, *py_value;
py_args = PyTuple_New(1);
py_value = PyByteArray_FromStringAndSize(buf, buf_size);
if (!py_value) {
Py_DECREF(py_args);
FATAL("Failed to convert arguments");
}
PyTuple_SetItem(py_args, 0, py_value);
py_value = PyObject_CallObject(
((py_mutator_t *)py_mutator)->py_functions[PY_FUNC_FUZZ_COUNT], py_args);
Py_DECREF(py_args);
if (py_value != NULL) {
#if PY_MAJOR_VERSION >= 3
u32 retcnt = (u32)PyLong_AsLong(py_value);
#else
u32 retcnt = PyInt_AsLong(py_value);
#endif
Py_DECREF(py_value);
return retcnt;
} else {
PyErr_Print();
FATAL("Call failed");
}
}
s32 post_trim_py(void *py_mutator, u8 success) {
PyObject *py_args, *py_value;
py_args = PyTuple_New(1);
py_value = PyBool_FromLong(success);
if (!py_value) {
Py_DECREF(py_args);
FATAL("Failed to convert arguments");
}
PyTuple_SetItem(py_args, 0, py_value);
py_value = PyObject_CallObject(
((py_mutator_t *)py_mutator)->py_functions[PY_FUNC_POST_TRIM], py_args);
Py_DECREF(py_args);
if (py_value != NULL) {
#if PY_MAJOR_VERSION >= 3
u32 retcnt = (u32)PyLong_AsLong(py_value);
#else
u32 retcnt = PyInt_AsLong(py_value);
#endif
Py_DECREF(py_value);
return retcnt;
} else {
PyErr_Print();
FATAL("Call failed");
}
}
size_t trim_py(void *py_mutator, u8 **out_buf) {
PyObject *py_args, *py_value;
size_t ret;
py_args = PyTuple_New(0);
py_value = PyObject_CallObject(
((py_mutator_t *)py_mutator)->py_functions[PY_FUNC_TRIM], py_args);
Py_DECREF(py_args);
if (py_value != NULL) {
ret = PyByteArray_Size(py_value);
*out_buf = afl_realloc(BUF_PARAMS(trim), ret);
if (unlikely(!*out_buf)) { PFATAL("alloc"); }
memcpy(*out_buf, PyByteArray_AsString(py_value), ret);
Py_DECREF(py_value);
} else {
PyErr_Print();
FATAL("Call failed");
}
return ret;
}
size_t havoc_mutation_py(void *py_mutator, u8 *buf, size_t buf_size,
u8 **out_buf, size_t max_size) {
size_t mutated_size;
PyObject *py_args, *py_value;
py_args = PyTuple_New(2);
/* buf */
py_value = PyByteArray_FromStringAndSize(buf, buf_size);
if (!py_value) {
Py_DECREF(py_args);
FATAL("Failed to convert arguments");
}
PyTuple_SetItem(py_args, 0, py_value);
/* max_size */
#if PY_MAJOR_VERSION >= 3
py_value = PyLong_FromLong(max_size);
#else
py_value = PyInt_FromLong(max_size);
#endif
if (!py_value) {
Py_DECREF(py_args);
FATAL("Failed to convert arguments");
}
PyTuple_SetItem(py_args, 1, py_value);
py_value = PyObject_CallObject(
((py_mutator_t *)py_mutator)->py_functions[PY_FUNC_HAVOC_MUTATION],
py_args);
Py_DECREF(py_args);
if (py_value != NULL) {
mutated_size = PyByteArray_Size(py_value);
if (mutated_size <= buf_size) {
/* We reuse the input buf here. */
*out_buf = buf;
} else {
/* A new buf is needed... */
*out_buf = afl_realloc(BUF_PARAMS(havoc), mutated_size);
if (unlikely(!*out_buf)) { PFATAL("alloc"); }
}
memcpy(*out_buf, PyByteArray_AsString(py_value), mutated_size);
Py_DECREF(py_value);
return mutated_size;
} else {
PyErr_Print();
FATAL("Call failed");
}
}
u8 havoc_mutation_probability_py(void *py_mutator) {
PyObject *py_args, *py_value;
py_args = PyTuple_New(0);
py_value = PyObject_CallObject(
((py_mutator_t *)py_mutator)
->py_functions[PY_FUNC_HAVOC_MUTATION_PROBABILITY],
py_args);
Py_DECREF(py_args);
if (py_value != NULL) {
long prob = PyLong_AsLong(py_value);
Py_DECREF(py_value);
return (u8)prob;
} else {
PyErr_Print();
FATAL("Call failed");
}
}
const char *introspection_py(void *py_mutator) {
PyObject *py_args, *py_value;
py_args = PyTuple_New(0);
py_value = PyObject_CallObject(
((py_mutator_t *)py_mutator)->py_functions[PY_FUNC_INTROSPECTION],
py_args);
Py_DECREF(py_args);
if (py_value == NULL) {
return NULL;
} else {
return PyByteArray_AsString(py_value);
}
}
u8 queue_get_py(void *py_mutator, const u8 *filename) {
PyObject *py_args, *py_value;
py_args = PyTuple_New(1);
// File name
#if PY_MAJOR_VERSION >= 3
py_value = PyUnicode_FromString(filename);
#else
py_value = PyString_FromString(filename);
#endif
if (!py_value) {
Py_DECREF(py_args);
FATAL("Failed to convert arguments");
}
PyTuple_SetItem(py_args, 0, py_value);
// Call Python function
py_value = PyObject_CallObject(
((py_mutator_t *)py_mutator)->py_functions[PY_FUNC_QUEUE_GET], py_args);
Py_DECREF(py_args);
if (py_value != NULL) {
int ret = PyObject_IsTrue(py_value);
Py_DECREF(py_value);
if (ret == -1) {
PyErr_Print();
FATAL("Failed to convert return value");
}
return (u8)ret & 0xFF;
} else {
PyErr_Print();
FATAL("Call failed");
}
}
void queue_new_entry_py(void *py_mutator, const u8 *filename_new_queue,
const u8 *filename_orig_queue) {
PyObject *py_args, *py_value;
py_args = PyTuple_New(2);
// New queue
#if PY_MAJOR_VERSION >= 3
py_value = PyUnicode_FromString(filename_new_queue);
#else
py_value = PyString_FromString(filename_new_queue);
#endif
if (!py_value) {
Py_DECREF(py_args);
FATAL("Failed to convert arguments");
}
PyTuple_SetItem(py_args, 0, py_value);
// Orig queue
py_value = Py_None;
if (filename_orig_queue) {
#if PY_MAJOR_VERSION >= 3
py_value = PyUnicode_FromString(filename_orig_queue);
#else
py_value = PyString_FromString(filename_orig_queue);
#endif
if (!py_value) {
Py_DECREF(py_args);
FATAL("Failed to convert arguments");
}
}
PyTuple_SetItem(py_args, 1, py_value);
// Call
py_value = PyObject_CallObject(
((py_mutator_t *)py_mutator)->py_functions[PY_FUNC_QUEUE_NEW_ENTRY],
py_args);
Py_DECREF(py_args);
if (py_value == NULL) {
PyErr_Print();
FATAL("Call failed");
}
}
#undef BUF_PARAMS
#endif /* USE_PYTHON */
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