diff options
Diffstat (limited to 'custom_mutators')
| -rw-r--r-- | custom_mutators/README.md | 8 | ||||
| -rw-r--r-- | custom_mutators/examples/Makefile | 7 | ||||
| -rw-r--r-- | custom_mutators/examples/README.md | 35 | ||||
| -rw-r--r-- | custom_mutators/examples/XmlMutatorMin.py | 348 | ||||
| -rw-r--r-- | custom_mutators/examples/common.py | 40 | ||||
| -rw-r--r-- | custom_mutators/examples/custom_mutator_helpers.h | 342 | ||||
| -rw-r--r-- | custom_mutators/examples/example.c | 376 | ||||
| -rw-r--r-- | custom_mutators/examples/example.py | 187 | ||||
| -rw-r--r-- | custom_mutators/examples/post_library_gif.so.c | 165 | ||||
| -rw-r--r-- | custom_mutators/examples/post_library_png.so.c | 163 | ||||
| -rw-r--r-- | custom_mutators/examples/simple-chunk-replace.py | 66 | ||||
| -rw-r--r-- | custom_mutators/examples/simple_example.c | 74 | ||||
| -rw-r--r-- | custom_mutators/examples/wrapper_afl_min.py | 123 | ||||
| -rw-r--r-- | custom_mutators/grammar_mutator/GRAMMAR_VERSION | 2 | ||||
| m--------- | custom_mutators/grammar_mutator/grammar_mutator | 0 |
15 files changed, 1935 insertions, 1 deletions
diff --git a/custom_mutators/README.md b/custom_mutators/README.md index b0444c85..5e1d0fe6 100644 --- a/custom_mutators/README.md +++ b/custom_mutators/README.md @@ -3,6 +3,14 @@ Custom mutators enhance and alter the mutation strategies of afl++. For further information and documentation on how to write your own, read [the docs](../docs/custom_mutators.md). +## Examples + +The `./examples` folder contains examples for custom mutators in python and C. + +## Rust + +In `./rust`, you will find rust bindings, including a simple example in `./rust/example` and an example for structured fuzzing, based on lain, in`./rust/example_lain`. + ## The afl++ Grammar Mutator If you use git to clone afl++, then the following will incorporate our diff --git a/custom_mutators/examples/Makefile b/custom_mutators/examples/Makefile new file mode 100644 index 00000000..9849f3f4 --- /dev/null +++ b/custom_mutators/examples/Makefile @@ -0,0 +1,7 @@ +all: libexamplemutator.so + +libexamplemutator.so: + $(CC) $(CFLAGS) -D_FORTIFY_SOURCE=2 -O3 -fPIC -shared -g -I ../../include example.c -o libexamplemutator.so + +clean: + rm -rf libexamplemutator.so diff --git a/custom_mutators/examples/README.md b/custom_mutators/examples/README.md new file mode 100644 index 00000000..655f7a5e --- /dev/null +++ b/custom_mutators/examples/README.md @@ -0,0 +1,35 @@ +# Examples for the custom mutator + +These are example and helper files for the custom mutator feature. +See [docs/custom_mutators.md](../../docs/custom_mutators.md) for more information + +Note that if you compile with python3.7 you must use python3 scripts, and if +you use python2.7 to compile python2 scripts! + +simple_example.c - most simplest example. generates a random sized buffer + filled with 'A' + +example.c - this is a simple example written in C and should be compiled to a + shared library. Use make to compile it and produce libexamplemutator.so + +example.py - this is the template you can use, the functions are there but they + are empty + +post_library_gif.so.c - fix a fuzz input to ensure it is valid for GIF + +post_library_png.so.c - fix a fuzz input to ensure it is valid for PNG + +simple-chunk-replace.py - this is a simple example where chunks are replaced + +common.py - this can be used for common functions and helpers. + the examples do not use this though. But you can :) + +wrapper_afl_min.py - mutation of XML documents, loads XmlMutatorMin.py + +XmlMutatorMin.py - module for XML mutation + +custom_mutator_helpers.h is an header that defines some helper routines +like surgical_havoc_mutate() that allow to perform a randomly chosen +mutation from a subset of the havoc mutations. +If you do so, you have to specify -I /path/to/AFLplusplus/include when +compiling. diff --git a/custom_mutators/examples/XmlMutatorMin.py b/custom_mutators/examples/XmlMutatorMin.py new file mode 100644 index 00000000..3e6cd0ff --- /dev/null +++ b/custom_mutators/examples/XmlMutatorMin.py @@ -0,0 +1,348 @@ +#!/usr/bin/python + +""" Mutation of XML documents, should be called from one of its wrappers (CLI, AFL, ...) """ + +from __future__ import print_function +from copy import deepcopy +from lxml import etree as ET +import random, re, io + + +########################### +# The XmlMutatorMin class # +########################### + + +class XmlMutatorMin: + + """ + Optionals parameters: + seed Seed used by the PRNG (default: "RANDOM") + verbose Verbosity (default: False) + """ + + def __init__(self, seed="RANDOM", verbose=False): + + """ Initialize seed, database and mutators """ + + # Verbosity + self.verbose = verbose + + # Initialize PRNG + self.seed = str(seed) + if self.seed == "RANDOM": + random.seed() + else: + if self.verbose: + print("Static seed '%s'" % self.seed) + random.seed(self.seed) + + # Initialize input and output documents + self.input_tree = None + self.tree = None + + # High-level mutators (no database needed) + hl_mutators_delete = [ + "del_node_and_children", + "del_node_but_children", + "del_attribute", + "del_content", + ] # Delete items + hl_mutators_fuzz = ["fuzz_attribute"] # Randomly change attribute values + + # Exposed mutators + self.hl_mutators_all = hl_mutators_fuzz + hl_mutators_delete + + def __parse_xml(self, xml): + + """ Parse an XML string. Basic wrapper around lxml.parse() """ + + try: + # Function parse() takes care of comments / DTD / processing instructions / ... + tree = ET.parse(io.BytesIO(xml)) + except ET.ParseError: + raise RuntimeError("XML isn't well-formed!") + except LookupError as e: + raise RuntimeError(e) + + # Return a document wrapper + return tree + + def __exec_among(self, module, functions, min_times, max_times): + + """ Randomly execute $functions between $min and $max times """ + + for i in xrange(random.randint(min_times, max_times)): + # Function names are mangled because they are "private" + getattr(module, "_XmlMutatorMin__" + random.choice(functions))() + + def __serialize_xml(self, tree): + + """ Serialize a XML document. Basic wrapper around lxml.tostring() """ + + return ET.tostring( + tree, with_tail=False, xml_declaration=True, encoding=tree.docinfo.encoding + ) + + def __ver(self, version): + + """ Helper for displaying lxml version numbers """ + + return ".".join(map(str, version)) + + def reset(self): + + """ Reset the mutator """ + + self.tree = deepcopy(self.input_tree) + + def init_from_string(self, input_string): + + """ Initialize the mutator from a XML string """ + + # Get a pointer to the top-element + self.input_tree = self.__parse_xml(input_string) + + # Get a working copy + self.tree = deepcopy(self.input_tree) + + def save_to_string(self): + + """ Return the current XML document as UTF-8 string """ + + # Return a text version of the tree + return self.__serialize_xml(self.tree) + + def __pick_element(self, exclude_root_node=False): + + """ Pick a random element from the current document """ + + # Get a list of all elements, but nodes like PI and comments + elems = list(self.tree.getroot().iter(tag=ET.Element)) + + # Is the root node excluded? + if exclude_root_node: + start = 1 + else: + start = 0 + + # Pick a random element + try: + elem_id = random.randint(start, len(elems) - 1) + elem = elems[elem_id] + except ValueError: + # Should only occurs if "exclude_root_node = True" + return (None, None) + + return (elem_id, elem) + + def __fuzz_attribute(self): + + """ Fuzz (part of) an attribute value """ + + # Select a node to modify + (rand_elem_id, rand_elem) = self.__pick_element() + + # Get all the attributes + attribs = rand_elem.keys() + + # Is there attributes? + if len(attribs) < 1: + if self.verbose: + print("No attribute: can't replace!") + return + + # Pick a random attribute + rand_attrib_id = random.randint(0, len(attribs) - 1) + rand_attrib = attribs[rand_attrib_id] + + # We have the attribute to modify + # Get its value + attrib_value = rand_elem.get(rand_attrib) + # print("- Value: " + attrib_value) + + # Should we work on the whole value? + func_call = "(?P<func>[a-zA-Z:\-]+)\((?P<args>.*?)\)" + p = re.compile(func_call) + l = p.findall(attrib_value) + if random.choice((True, False)) and l: + # Randomly pick one the function calls + (func, args) = random.choice(l) + # Split by "," and randomly pick one of the arguments + value = random.choice(args.split(",")) + # Remove superfluous characters + unclean_value = value + value = value.strip(" ").strip("'") + # print("Selected argument: [%s]" % value) + else: + value = attrib_value + + # For each type, define some possible replacement values + choices_number = ( + "0", + "11111", + "-128", + "2", + "-1", + "1/3", + "42/0", + "1094861636 idiv 1.0", + "-1123329771506872 idiv 3.8", + "17=$numericRTF", + str(3 + random.randrange(0, 100)), + ) + + choices_letter = ( + "P" * (25 * random.randrange(1, 100)), + "%s%s%s%s%s%s", + "foobar", + ) + + choices_alnum = ( + "Abc123", + "020F0302020204030204", + "020F0302020204030204" * (random.randrange(5, 20)), + ) + + # Fuzz the value + if random.choice((True, False)) and value == "": + + # Empty + new_value = value + + elif random.choice((True, False)) and value.isdigit(): + + # Numbers + new_value = random.choice(choices_number) + + elif random.choice((True, False)) and value.isalpha(): + + # Letters + new_value = random.choice(choices_letter) + + elif random.choice((True, False)) and value.isalnum(): + + # Alphanumeric + new_value = random.choice(choices_alnum) + + else: + + # Default type + new_value = random.choice(choices_alnum + choices_letter + choices_number) + + # If we worked on a substring, apply changes to the whole string + if value != attrib_value: + # No ' around empty values + if new_value != "" and value != "": + new_value = "'" + new_value + "'" + # Apply changes + new_value = attrib_value.replace(unclean_value, new_value) + + # Log something + if self.verbose: + print( + "Fuzzing attribute #%i '%s' of tag #%i '%s'" + % (rand_attrib_id, rand_attrib, rand_elem_id, rand_elem.tag) + ) + + # Modify the attribute + rand_elem.set(rand_attrib, new_value.decode("utf-8")) + + def __del_node_and_children(self): + + """High-level minimizing mutator + Delete a random node and its children (i.e. delete a random tree)""" + + self.__del_node(True) + + def __del_node_but_children(self): + + """High-level minimizing mutator + Delete a random node but its children (i.e. link them to the parent of the deleted node)""" + + self.__del_node(False) + + def __del_node(self, delete_children): + + """ Called by the __del_node_* mutators """ + + # Select a node to modify (but the root one) + (rand_elem_id, rand_elem) = self.__pick_element(exclude_root_node=True) + + # If the document includes only a top-level element + # Then we can't pick a element (given that "exclude_root_node = True") + + # Is the document deep enough? + if rand_elem is None: + if self.verbose: + print("Can't delete a node: document not deep enough!") + return + + # Log something + if self.verbose: + but_or_and = "and" if delete_children else "but" + print( + "Deleting tag #%i '%s' %s its children" + % (rand_elem_id, rand_elem.tag, but_or_and) + ) + + if delete_children is False: + # Link children of the random (soon to be deleted) node to its parent + for child in rand_elem: + rand_elem.getparent().append(child) + + # Remove the node + rand_elem.getparent().remove(rand_elem) + + def __del_content(self): + + """High-level minimizing mutator + Delete the attributes and children of a random node""" + + # Select a node to modify + (rand_elem_id, rand_elem) = self.__pick_element() + + # Log something + if self.verbose: + print("Reseting tag #%i '%s'" % (rand_elem_id, rand_elem.tag)) + + # Reset the node + rand_elem.clear() + + def __del_attribute(self): + + """High-level minimizing mutator + Delete a random attribute from a random node""" + + # Select a node to modify + (rand_elem_id, rand_elem) = self.__pick_element() + + # Get all the attributes + attribs = rand_elem.keys() + + # Is there attributes? + if len(attribs) < 1: + if self.verbose: + print("No attribute: can't delete!") + return + + # Pick a random attribute + rand_attrib_id = random.randint(0, len(attribs) - 1) + rand_attrib = attribs[rand_attrib_id] + + # Log something + if self.verbose: + print( + "Deleting attribute #%i '%s' of tag #%i '%s'" + % (rand_attrib_id, rand_attrib, rand_elem_id, rand_elem.tag) + ) + + # Delete the attribute + rand_elem.attrib.pop(rand_attrib) + + def mutate(self, min=1, max=5): + + """ Execute some high-level mutators between $min and $max times, then some medium-level ones """ + + # High-level mutation + self.__exec_among(self, self.hl_mutators_all, min, max) diff --git a/custom_mutators/examples/common.py b/custom_mutators/examples/common.py new file mode 100644 index 00000000..44a5056a --- /dev/null +++ b/custom_mutators/examples/common.py @@ -0,0 +1,40 @@ +#!/usr/bin/env python +# encoding: utf-8 +""" +Module containing functions shared between multiple AFL modules + +@author: Christian Holler (:decoder) + +@license: + +This Source Code Form is subject to the terms of the Mozilla Public +License, v. 2.0. If a copy of the MPL was not distributed with this +file, You can obtain one at http://mozilla.org/MPL/2.0/. + +@contact: choller@mozilla.com +""" + +from __future__ import print_function +import random +import os +import re + + +def randel(l): + if not l: + return None + return l[random.randint(0, len(l) - 1)] + + +def randel_pop(l): + if not l: + return None + return l.pop(random.randint(0, len(l) - 1)) + + +def write_exc_example(data, exc): + exc_name = re.sub(r"[^a-zA-Z0-9]", "_", repr(exc)) + + if not os.path.exists(exc_name): + with open(exc_name, "w") as f: + f.write(data) diff --git a/custom_mutators/examples/custom_mutator_helpers.h b/custom_mutators/examples/custom_mutator_helpers.h new file mode 100644 index 00000000..62e6efba --- /dev/null +++ b/custom_mutators/examples/custom_mutator_helpers.h @@ -0,0 +1,342 @@ +#ifndef CUSTOM_MUTATOR_HELPERS +#define CUSTOM_MUTATOR_HELPERS + +#include "config.h" +#include "types.h" +#include <stdlib.h> + +#define INITIAL_GROWTH_SIZE (64) + +#define RAND_BELOW(limit) (rand() % (limit)) + +/* Use in a struct: creates a name_buf and a name_size variable. */ +#define BUF_VAR(type, name) \ + type * name##_buf; \ + size_t name##_size; +/* this fills in `&structptr->something_buf, &structptr->something_size`. */ +#define BUF_PARAMS(struct, name) \ + (void **)&struct->name##_buf, &struct->name##_size + +typedef struct { + +} afl_t; + +static void surgical_havoc_mutate(u8 *out_buf, s32 begin, s32 end) { + + static s8 interesting_8[] = {INTERESTING_8}; + static s16 interesting_16[] = {INTERESTING_8, INTERESTING_16}; + static s32 interesting_32[] = {INTERESTING_8, INTERESTING_16, INTERESTING_32}; + + switch (RAND_BELOW(12)) { + + case 0: { + + /* Flip a single bit somewhere. Spooky! */ + + s32 bit_idx = ((RAND_BELOW(end - begin) + begin) << 3) + RAND_BELOW(8); + + out_buf[bit_idx >> 3] ^= 128 >> (bit_idx & 7); + + break; + + } + + case 1: { + + /* Set byte to interesting value. */ + + u8 val = interesting_8[RAND_BELOW(sizeof(interesting_8))]; + out_buf[(RAND_BELOW(end - begin) + begin)] = val; + + break; + + } + + case 2: { + + /* Set word to interesting value, randomly choosing endian. */ + + if (end - begin < 2) break; + + s32 byte_idx = (RAND_BELOW(end - begin) + begin); + + if (byte_idx >= end - 1) break; + + switch (RAND_BELOW(2)) { + + case 0: + *(u16 *)(out_buf + byte_idx) = + interesting_16[RAND_BELOW(sizeof(interesting_16) >> 1)]; + break; + case 1: + *(u16 *)(out_buf + byte_idx) = + SWAP16(interesting_16[RAND_BELOW(sizeof(interesting_16) >> 1)]); + break; + + } + + break; + + } + + case 3: { + + /* Set dword to interesting value, randomly choosing endian. */ + + if (end - begin < 4) break; + + s32 byte_idx = (RAND_BELOW(end - begin) + begin); + + if (byte_idx >= end - 3) break; + + switch (RAND_BELOW(2)) { + + case 0: + *(u32 *)(out_buf + byte_idx) = + interesting_32[RAND_BELOW(sizeof(interesting_32) >> 2)]; + break; + case 1: + *(u32 *)(out_buf + byte_idx) = + SWAP32(interesting_32[RAND_BELOW(sizeof(interesting_32) >> 2)]); + break; + + } + + break; + + } + + case 4: { + + /* Set qword to interesting value, randomly choosing endian. */ + + if (end - begin < 8) break; + + s32 byte_idx = (RAND_BELOW(end - begin) + begin); + + if (byte_idx >= end - 7) break; + + switch (RAND_BELOW(2)) { + + case 0: + *(u64 *)(out_buf + byte_idx) = + (s64)interesting_32[RAND_BELOW(sizeof(interesting_32) >> 2)]; + break; + case 1: + *(u64 *)(out_buf + byte_idx) = SWAP64( + (s64)interesting_32[RAND_BELOW(sizeof(interesting_32) >> 2)]); + break; + + } + + break; + + } + + case 5: { + + /* Randomly subtract from byte. */ + + out_buf[(RAND_BELOW(end - begin) + begin)] -= 1 + RAND_BELOW(ARITH_MAX); + + break; + + } + + case 6: { + + /* Randomly add to byte. */ + + out_buf[(RAND_BELOW(end - begin) + begin)] += 1 + RAND_BELOW(ARITH_MAX); + + break; + + } + + case 7: { + + /* Randomly subtract from word, random endian. */ + + if (end - begin < 2) break; + + s32 byte_idx = (RAND_BELOW(end - begin) + begin); + + if (byte_idx >= end - 1) break; + + if (RAND_BELOW(2)) { + + *(u16 *)(out_buf + byte_idx) -= 1 + RAND_BELOW(ARITH_MAX); + + } else { + + u16 num = 1 + RAND_BELOW(ARITH_MAX); + + *(u16 *)(out_buf + byte_idx) = + SWAP16(SWAP16(*(u16 *)(out_buf + byte_idx)) - num); + + } + + break; + + } + + case 8: { + + /* Randomly add to word, random endian. */ + + if (end - begin < 2) break; + + s32 byte_idx = (RAND_BELOW(end - begin) + begin); + + if (byte_idx >= end - 1) break; + + if (RAND_BELOW(2)) { + + *(u16 *)(out_buf + byte_idx) += 1 + RAND_BELOW(ARITH_MAX); + + } else { + + u16 num = 1 + RAND_BELOW(ARITH_MAX); + + *(u16 *)(out_buf + byte_idx) = + SWAP16(SWAP16(*(u16 *)(out_buf + byte_idx)) + num); + + } + + break; + + } + + case 9: { + + /* Randomly subtract from dword, random endian. */ + + if (end - begin < 4) break; + + s32 byte_idx = (RAND_BELOW(end - begin) + begin); + + if (byte_idx >= end - 3) break; + + if (RAND_BELOW(2)) { + + *(u32 *)(out_buf + byte_idx) -= 1 + RAND_BELOW(ARITH_MAX); + + } else { + + u32 num = 1 + RAND_BELOW(ARITH_MAX); + + *(u32 *)(out_buf + byte_idx) = + SWAP32(SWAP32(*(u32 *)(out_buf + byte_idx)) - num); + + } + + break; + + } + + case 10: { + + /* Randomly add to dword, random endian. */ + + if (end - begin < 4) break; + + s32 byte_idx = (RAND_BELOW(end - begin) + begin); + + if (byte_idx >= end - 3) break; + + if (RAND_BELOW(2)) { + + *(u32 *)(out_buf + byte_idx) += 1 + RAND_BELOW(ARITH_MAX); + + } else { + + u32 num = 1 + RAND_BELOW(ARITH_MAX); + + *(u32 *)(out_buf + byte_idx) = + SWAP32(SWAP32(*(u32 *)(out_buf + byte_idx)) + num); + + } + + break; + + } + + case 11: { + + /* Just set a random byte to a random value. Because, + why not. We use XOR with 1-255 to eliminate the + possibility of a no-op. */ + + out_buf[(RAND_BELOW(end - begin) + begin)] ^= 1 + RAND_BELOW(255); + + break; + + } + + } + +} + +/* This function calculates the next power of 2 greater or equal its argument. + @return The rounded up power of 2 (if no overflow) or 0 on overflow. +*/ +static inline size_t next_pow2(size_t in) { + + if (in == 0 || in > (size_t)-1) + return 0; /* avoid undefined behaviour under-/overflow */ + size_t out = in - 1; + out |= out >> 1; + out |= out >> 2; + out |= out >> 4; + out |= out >> 8; + out |= out >> 16; + return out + 1; + +} + +/* This function makes sure *size is > size_needed after call. + It will realloc *buf otherwise. + *size will grow exponentially as per: + https://blog.mozilla.org/nnethercote/2014/11/04/please-grow-your-buffers-exponentially/ + Will return NULL and free *buf if size_needed is <1 or realloc failed. + @return For convenience, this function returns *buf. + */ +static inline void *maybe_grow(void **buf, size_t *size, size_t size_needed) { + + /* No need to realloc */ + if (likely(size_needed && *size >= size_needed)) return *buf; + + /* No initial size was set */ + if (size_needed < INITIAL_GROWTH_SIZE) size_needed = INITIAL_GROWTH_SIZE; + + /* grow exponentially */ + size_t next_size = next_pow2(size_needed); + + /* handle overflow */ + if (!next_size) { next_size = size_needed; } + + /* alloc */ + *buf = realloc(*buf, next_size); + *size = *buf ? next_size : 0; + + return *buf; + +} + +/* Swaps buf1 ptr and buf2 ptr, as well as their sizes */ +static inline void afl_swap_bufs(void **buf1, size_t *size1, void **buf2, + size_t *size2) { + + void * scratch_buf = *buf1; + size_t scratch_size = *size1; + *buf1 = *buf2; + *size1 = *size2; + *buf2 = scratch_buf; + *size2 = scratch_size; + +} + +#undef INITIAL_GROWTH_SIZE + +#endif + diff --git a/custom_mutators/examples/example.c b/custom_mutators/examples/example.c new file mode 100644 index 00000000..23add128 --- /dev/null +++ b/custom_mutators/examples/example.c @@ -0,0 +1,376 @@ +/* + New Custom Mutator for AFL++ + Written by Khaled Yakdan <yakdan@code-intelligence.de> + Andrea Fioraldi <andreafioraldi@gmail.com> + Shengtuo Hu <h1994st@gmail.com> + Dominik Maier <mail@dmnk.co> +*/ + +// You need to use -I /path/to/AFLplusplus/include +#include "custom_mutator_helpers.h" + +#include <stdint.h> +#include <stdlib.h> +#include <string.h> +#include <stdio.h> + +#define DATA_SIZE (100) + +static const char *commands[] = { + + "GET", + "PUT", + "DEL", + +}; + +typedef struct my_mutator { + + afl_t *afl; + + // any additional data here! + size_t trim_size_current; + int trimmming_steps; + int cur_step; + + // Reused buffers: + BUF_VAR(u8, fuzz); + BUF_VAR(u8, data); + BUF_VAR(u8, havoc); + BUF_VAR(u8, trim); + BUF_VAR(u8, post_process); + +} my_mutator_t; + +/** + * Initialize this custom mutator + * + * @param[in] afl a pointer to the internal state object. Can be ignored for + * now. + * @param[in] seed A seed for this mutator - the same seed should always mutate + * in the same way. + * @return Pointer to the data object this custom mutator instance should use. + * There may be multiple instances of this mutator in one afl-fuzz run! + * Return NULL on error. + */ +my_mutator_t *afl_custom_init(afl_t *afl, unsigned int seed) { + + srand(seed); // needed also by surgical_havoc_mutate() + + my_mutator_t *data = calloc(1, sizeof(my_mutator_t)); + if (!data) { + + perror("afl_custom_init alloc"); + return NULL; + + } + + data->afl = afl; + + return data; + +} + +/** + * Perform custom mutations on a given input + * + * (Optional for now. Required in the future) + * + * @param[in] data pointer returned in afl_custom_init for this fuzz case + * @param[in] buf Pointer to input data to be mutated + * @param[in] buf_size Size of input data + * @param[out] out_buf the buffer we will work on. we can reuse *buf. NULL on + * error. + * @param[in] add_buf Buffer containing the additional test case + * @param[in] add_buf_size Size of the additional test case + * @param[in] max_size Maximum size of the mutated output. The mutation must not + * produce data larger than max_size. + * @return Size of the mutated output. + */ +size_t afl_custom_fuzz(my_mutator_t *data, uint8_t *buf, size_t buf_size, + u8 **out_buf, uint8_t *add_buf, + size_t add_buf_size, // add_buf can be NULL + size_t max_size) { + + // Make sure that the packet size does not exceed the maximum size expected by + // the fuzzer + size_t mutated_size = DATA_SIZE <= max_size ? DATA_SIZE : max_size; + + // maybe_grow is optimized to be quick for reused buffers. + u8 *mutated_out = maybe_grow(BUF_PARAMS(data, fuzz), mutated_size); + if (!mutated_out) { + + *out_buf = NULL; + perror("custom mutator allocation (maybe_grow)"); + return 0; /* afl-fuzz will very likely error out after this. */ + + } + + // Randomly select a command string to add as a header to the packet + memcpy(mutated_out, commands[rand() % 3], 3); + + // Mutate the payload of the packet + int i; + for (i = 0; i < 8; ++i) { + + // Randomly perform one of the (no len modification) havoc mutations + surgical_havoc_mutate(mutated_out, 3, mutated_size); + + } + + *out_buf = mutated_out; + return mutated_size; + +} + +/** + * A post-processing function to use right before AFL writes the test case to + * disk in order to execute the target. + * + * (Optional) If this functionality is not needed, simply don't define this + * function. + * + * @param[in] data pointer returned in afl_custom_init for this fuzz case + * @param[in] buf Buffer containing the test case to be executed + * @param[in] buf_size Size of the test case + * @param[out] out_buf Pointer to the buffer containing the test case after + * processing. External library should allocate memory for out_buf. + * The buf pointer may be reused (up to the given buf_size); + * @return Size of the output buffer after processing or the needed amount. + * A return of 0 indicates an error. + */ +size_t afl_custom_post_process(my_mutator_t *data, uint8_t *buf, + size_t buf_size, uint8_t **out_buf) { + + uint8_t *post_process_buf = + maybe_grow(BUF_PARAMS(data, post_process), buf_size + 5); + if (!post_process_buf) { + + perror("custom mutator realloc failed."); + *out_buf = NULL; + return 0; + + } + + memcpy(post_process_buf + 5, buf, buf_size); + post_process_buf[0] = 'A'; + post_process_buf[1] = 'F'; + post_process_buf[2] = 'L'; + post_process_buf[3] = '+'; + post_process_buf[4] = '+'; + + *out_buf = post_process_buf; + + return buf_size + 5; + +} + +/** + * This method is called at the start of each trimming operation and receives + * the initial buffer. It should return the amount of iteration steps possible + * on this input (e.g. if your input has n elements and you want to remove + * them one by one, return n, if you do a binary search, return log(n), + * and so on...). + * + * If your trimming algorithm doesn't allow you to determine the amount of + * (remaining) steps easily (esp. while running), then you can alternatively + * return 1 here and always return 0 in post_trim until you are finished and + * no steps remain. In that case, returning 1 in post_trim will end the + * trimming routine. The whole current index/max iterations stuff is only used + * to show progress. + * + * (Optional) + * + * @param data pointer returned in afl_custom_init for this fuzz case + * @param buf Buffer containing the test case + * @param buf_size Size of the test case + * @return The amount of possible iteration steps to trim the input. + * negative on error. + */ +int32_t afl_custom_init_trim(my_mutator_t *data, uint8_t *buf, + size_t buf_size) { + + // We simply trim once + data->trimmming_steps = 1; + + data->cur_step = 0; + + if (!maybe_grow(BUF_PARAMS(data, trim), buf_size)) { + + perror("init_trim grow"); + return -1; + + } + + memcpy(data->trim_buf, buf, buf_size); + + data->trim_size_current = buf_size; + + return data->trimmming_steps; + +} + +/** + * This method is called for each trimming operation. It doesn't have any + * arguments because we already have the initial buffer from init_trim and we + * can memorize the current state in *data. This can also save + * reparsing steps for each iteration. It should return the trimmed input + * buffer, where the returned data must not exceed the initial input data in + * length. Returning anything that is larger than the original data (passed + * to init_trim) will result in a fatal abort of AFLFuzz. + * + * (Optional) + * + * @param[in] data pointer returned in afl_custom_init for this fuzz case + * @param[out] out_buf Pointer to the buffer containing the trimmed test case. + * External library should allocate memory for out_buf. + * AFL++ will not release the memory after saving the test case. + * Keep a ref in *data. + * *out_buf = NULL is treated as error. + * @return Pointer to the size of the trimmed test case + */ +size_t afl_custom_trim(my_mutator_t *data, uint8_t **out_buf) { + + *out_buf = data->trim_buf; + + // Remove the last byte of the trimming input + return data->trim_size_current - 1; + +} + +/** + * This method is called after each trim operation to inform you if your + * trimming step was successful or not (in terms of coverage). If you receive + * a failure here, you should reset your input to the last known good state. + * + * (Optional) + * + * @param[in] data pointer returned in afl_custom_init for this fuzz case + * @param success Indicates if the last trim operation was successful. + * @return The next trim iteration index (from 0 to the maximum amount of + * steps returned in init_trim). negative ret on failure. + */ +int32_t afl_custom_post_trim(my_mutator_t *data, int success) { + + if (success) { + + ++data->cur_step; + return data->cur_step; + + } + + return data->trimmming_steps; + +} + +/** + * Perform a single custom mutation on a given input. + * This mutation is stacked with the other muatations in havoc. + * + * (Optional) + * + * @param[in] data pointer returned in afl_custom_init for this fuzz case + * @param[in] buf Pointer to the input data to be mutated and the mutated + * output + * @param[in] buf_size Size of input data + * @param[out] out_buf The output buffer. buf can be reused, if the content + * fits. *out_buf = NULL is treated as error. + * @param[in] max_size Maximum size of the mutated output. The mutation must + * not produce data larger than max_size. + * @return Size of the mutated output. + */ +size_t afl_custom_havoc_mutation(my_mutator_t *data, u8 *buf, size_t buf_size, + u8 **out_buf, size_t max_size) { + + if (buf_size == 0) { + + *out_buf = maybe_grow(BUF_PARAMS(data, havoc), 1); + if (!*out_buf) { + + perror("custom havoc: maybe_grow"); + return 0; + + } + + **out_buf = rand() % 256; + buf_size = 1; + + } else { + + // We reuse buf here. It's legal and faster. + *out_buf = buf; + + } + + size_t victim = rand() % buf_size; + (*out_buf)[victim] += rand() % 10; + + return buf_size; + +} + +/** + * Return the probability (in percentage) that afl_custom_havoc_mutation + * is called in havoc. By default it is 6 %. + * + * (Optional) + * + * @param[in] data pointer returned in afl_custom_init for this fuzz case + * @return The probability (0-100). + */ +uint8_t afl_custom_havoc_mutation_probability(my_mutator_t *data) { + + return 5; // 5 % + +} + +/** + * Determine whether the fuzzer should fuzz the queue entry or not. + * + * (Optional) + * + * @param[in] data pointer returned in afl_custom_init for this fuzz case + * @param filename File name of the test case in the queue entry + * @return Return True(1) if the fuzzer will fuzz the queue entry, and + * False(0) otherwise. + */ +uint8_t afl_custom_queue_get(my_mutator_t *data, const uint8_t *filename) { + + return 1; + +} + +/** + * Allow for additional analysis (e.g. calling a different tool that does a + * different kind of coverage and saves this for the custom mutator). + * + * (Optional) + * + * @param data pointer returned in afl_custom_init for this fuzz case + * @param filename_new_queue File name of the new queue entry + * @param filename_orig_queue File name of the original queue entry + */ +void afl_custom_queue_new_entry(my_mutator_t * data, + const uint8_t *filename_new_queue, + const uint8_t *filename_orig_queue) { + + /* Additional analysis on the original or new test case */ + +} + +/** + * Deinitialize everything + * + * @param data The data ptr from afl_custom_init + */ +void afl_custom_deinit(my_mutator_t *data) { + + free(data->post_process_buf); + free(data->havoc_buf); + free(data->data_buf); + free(data->fuzz_buf); + free(data->trim_buf); + free(data); + +} + diff --git a/custom_mutators/examples/example.py b/custom_mutators/examples/example.py new file mode 100644 index 00000000..3a6d22e4 --- /dev/null +++ b/custom_mutators/examples/example.py @@ -0,0 +1,187 @@ +#!/usr/bin/env python +# encoding: utf-8 +""" +Example Python Module for AFLFuzz + +@author: Christian Holler (:decoder) + +@license: + +This Source Code Form is subject to the terms of the Mozilla Public +License, v. 2.0. If a copy of the MPL was not distributed with this +file, You can obtain one at http://mozilla.org/MPL/2.0/. + +@contact: choller@mozilla.com +""" + +import random + + +COMMANDS = [ + b"GET", + b"PUT", + b"DEL", + b"AAAAAAAAAAAAAAAAA", +] + + +def init(seed): + """ + Called once when AFLFuzz starts up. Used to seed our RNG. + + @type seed: int + @param seed: A 32-bit random value + """ + random.seed(seed) + + +def deinit(): + pass + + +def fuzz(buf, add_buf, max_size): + """ + Called per fuzzing iteration. + + @type buf: bytearray + @param buf: The buffer that should be mutated. + + @type add_buf: bytearray + @param add_buf: A second buffer that can be used as mutation source. + + @type max_size: int + @param max_size: Maximum size of the mutated output. The mutation must not + produce data larger than max_size. + + @rtype: bytearray + @return: A new bytearray containing the mutated data + """ + ret = bytearray(100) + + ret[:3] = random.choice(COMMANDS) + + return ret + + +# Uncomment and implement the following methods if you want to use a custom +# trimming algorithm. See also the documentation for a better API description. + +# def init_trim(buf): +# ''' +# Called per trimming iteration. +# +# @type buf: bytearray +# @param buf: The buffer that should be trimmed. +# +# @rtype: int +# @return: The maximum number of trimming steps. +# ''' +# global ... +# +# # Initialize global variables +# +# # Figure out how many trimming steps are possible. +# # If this is not possible for your trimming, you can +# # return 1 instead and always return 0 in post_trim +# # until you are done (then you return 1). +# +# return steps +# +# def trim(): +# ''' +# Called per trimming iteration. +# +# @rtype: bytearray +# @return: A new bytearray containing the trimmed data. +# ''' +# global ... +# +# # Implement the actual trimming here +# +# return bytearray(...) +# +# def post_trim(success): +# ''' +# Called after each trimming operation. +# +# @type success: bool +# @param success: Indicates if the last trim operation was successful. +# +# @rtype: int +# @return: The next trim index (0 to max number of steps) where max +# number of steps indicates the trimming is done. +# ''' +# global ... +# +# if not success: +# # Restore last known successful input, determine next index +# else: +# # Just determine the next index, based on what was successfully +# # removed in the last step +# +# return next_index +# +# def post_process(buf): +# ''' +# Called just before the execution to write the test case in the format +# expected by the target +# +# @type buf: bytearray +# @param buf: The buffer containing the test case to be executed +# +# @rtype: bytearray +# @return: The buffer containing the test case after +# ''' +# return buf +# +# def havoc_mutation(buf, max_size): +# ''' +# Perform a single custom mutation on a given input. +# +# @type buf: bytearray +# @param buf: The buffer that should be mutated. +# +# @type max_size: int +# @param max_size: Maximum size of the mutated output. The mutation must not +# produce data larger than max_size. +# +# @rtype: bytearray +# @return: A new bytearray containing the mutated data +# ''' +# return mutated_buf +# +# def havoc_mutation_probability(): +# ''' +# Called for each `havoc_mutation`. Return the probability (in percentage) +# that `havoc_mutation` is called in havoc. Be default it is 6%. +# +# @rtype: int +# @return: The probability (0-100) +# ''' +# return prob +# +# def queue_get(filename): +# ''' +# Called at the beginning of each fuzz iteration to determine whether the +# test case should be fuzzed +# +# @type filename: str +# @param filename: File name of the test case in the current queue entry +# +# @rtype: bool +# @return: Return True if the custom mutator decides to fuzz the test case, +# and False otherwise +# ''' +# return True +# +# def queue_new_entry(filename_new_queue, filename_orig_queue): +# ''' +# Called after adding a new test case to the queue +# +# @type filename_new_queue: str +# @param filename_new_queue: File name of the new queue entry +# +# @type filename_orig_queue: str +# @param filename_orig_queue: File name of the original queue entry +# ''' +# pass diff --git a/custom_mutators/examples/post_library_gif.so.c b/custom_mutators/examples/post_library_gif.so.c new file mode 100644 index 00000000..ac10f409 --- /dev/null +++ b/custom_mutators/examples/post_library_gif.so.c @@ -0,0 +1,165 @@ +/* + american fuzzy lop++ - postprocessor library example + -------------------------------------------------- + + Originally written by Michal Zalewski + Edited by Dominik Maier, 2020 + + Copyright 2015 Google Inc. 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 + + Postprocessor libraries can be passed to afl-fuzz to perform final cleanup + of any mutated test cases - for example, to fix up checksums in PNG files. + + Please heed the following warnings: + + 1) In almost all cases, it is more productive to comment out checksum logic + in the targeted binary (as shown in ../libpng_no_checksum/). One possible + exception is the process of fuzzing binary-only software in QEMU mode. + + 2) The use of postprocessors for anything other than checksums is + questionable and may cause more harm than good. AFL is normally pretty good + about dealing with length fields, magic values, etc. + + 3) Postprocessors that do anything non-trivial must be extremely robust to + gracefully handle malformed data and other error conditions - otherwise, + they will crash and take afl-fuzz down with them. Be wary of reading past + *len and of integer overflows when calculating file offsets. + + In other words, THIS IS PROBABLY NOT WHAT YOU WANT - unless you really, + honestly know what you're doing =) + + With that out of the way: the postprocessor library is passed to afl-fuzz + via AFL_POST_LIBRARY. The library must be compiled with: + + gcc -shared -Wall -O3 post_library.so.c -o post_library.so + + AFL will call the afl_custom_post_process() function for every mutated output + buffer. From there, you have three choices: + + 1) If you don't want to modify the test case, simply set `*out_buf = in_buf` + and return the original `len`. + + 2) If you want to skip this test case altogether and have AFL generate a + new one, return 0 or set `*out_buf = NULL`. + Use this sparingly - it's faster than running the target program + with patently useless inputs, but still wastes CPU time. + + 3) If you want to modify the test case, allocate an appropriately-sized + buffer, move the data into that buffer, make the necessary changes, and + then return the new pointer as out_buf. Return an appropriate len + afterwards. + + Note that the buffer will *not* be freed for you. To avoid memory leaks, + you need to free it or reuse it on subsequent calls (as shown below). + + *** Feel free to reuse the original 'in_buf' BUFFER and return it. *** + + Aight. The example below shows a simple postprocessor that tries to make + sure that all input files start with "GIF89a". + + PS. If you don't like C, you can try out the unix-based wrapper from + Ben Nagy instead: https://github.com/bnagy/aflfix + + */ + +#include <stdio.h> +#include <stdlib.h> +#include <string.h> + +/* Header that must be present at the beginning of every test case: */ + +#define HEADER "GIF89a" + +typedef struct post_state { + + unsigned char *buf; + size_t size; + +} post_state_t; + +void *afl_custom_init(void *afl) { + + post_state_t *state = malloc(sizeof(post_state_t)); + if (!state) { + + perror("malloc"); + return NULL; + + } + + state->buf = calloc(sizeof(unsigned char), 4096); + if (!state->buf) { + + free(state); + perror("calloc"); + return NULL; + + } + + return state; + +} + +/* The actual postprocessor routine called by afl-fuzz: */ + +size_t afl_custom_post_process(post_state_t *data, unsigned char *in_buf, + unsigned int len, unsigned char **out_buf) { + + /* Skip execution altogether for buffers shorter than 6 bytes (just to + show how it's done). We can trust len to be sane. */ + + if (len < strlen(HEADER)) return 0; + + /* Do nothing for buffers that already start with the expected header. */ + + if (!memcmp(in_buf, HEADER, strlen(HEADER))) { + + *out_buf = in_buf; + return len; + + } + + /* Allocate memory for new buffer, reusing previous allocation if + possible. */ + + *out_buf = realloc(data->buf, len); + + /* If we're out of memory, the most graceful thing to do is to return the + original buffer and give up on modifying it. Let AFL handle OOM on its + own later on. */ + + if (!*out_buf) { + + *out_buf = in_buf; + return len; + + } + + /* Copy the original data to the new location. */ + + memcpy(*out_buf, in_buf, len); + + /* Insert the new header. */ + + memcpy(*out_buf, HEADER, strlen(HEADER)); + + /* Return the new len. It hasn't changed, so it's just len. */ + + return len; + +} + +/* Gets called afterwards */ +void afl_custom_deinit(post_state_t *data) { + + free(data->buf); + free(data); + +} + diff --git a/custom_mutators/examples/post_library_png.so.c b/custom_mutators/examples/post_library_png.so.c new file mode 100644 index 00000000..941f7e55 --- /dev/null +++ b/custom_mutators/examples/post_library_png.so.c @@ -0,0 +1,163 @@ +/* + american fuzzy lop++ - postprocessor for PNG + ------------------------------------------ + + Originally written by Michal Zalewski + + Copyright 2015 Google Inc. All rights reserved. + Adapted to the new API, 2020 by Dominik Maier + + 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 + + See post_library.so.c for a general discussion of how to implement + postprocessors. This specific postprocessor attempts to fix up PNG + checksums, providing a slightly more complicated example than found + in post_library.so.c. + + Compile with: + + gcc -shared -Wall -O3 post_library_png.so.c -o post_library_png.so -lz + + */ + +#include <stdio.h> +#include <stdlib.h> +#include <stdint.h> +#include <string.h> +#include <zlib.h> + +#include <arpa/inet.h> + +/* A macro to round an integer up to 4 kB. */ + +#define UP4K(_i) ((((_i) >> 12) + 1) << 12) + +typedef struct post_state { + + unsigned char *buf; + size_t size; + +} post_state_t; + +void *afl_custom_init(void *afl) { + + post_state_t *state = malloc(sizeof(post_state_t)); + if (!state) { + + perror("malloc"); + return NULL; + + } + + state->buf = calloc(sizeof(unsigned char), 4096); + if (!state->buf) { + + free(state); + perror("calloc"); + return NULL; + + } + + return state; + +} + +size_t afl_custom_post_process(post_state_t *data, const unsigned char *in_buf, + unsigned int len, + const unsigned char **out_buf) { + + unsigned char *new_buf = (unsigned char *)in_buf; + unsigned int pos = 8; + + /* Don't do anything if there's not enough room for the PNG header + (8 bytes). */ + + if (len < 8) { + + *out_buf = in_buf; + return len; + + } + + /* Minimum size of a zero-length PNG chunk is 12 bytes; if we + don't have that, we can bail out. */ + + while (pos + 12 <= len) { + + unsigned int chunk_len, real_cksum, file_cksum; + + /* Chunk length is the first big-endian dword in the chunk. */ + + chunk_len = ntohl(*(uint32_t *)(in_buf + pos)); + + /* Bail out if chunk size is too big or goes past EOF. */ + + if (chunk_len > 1024 * 1024 || pos + 12 + chunk_len > len) break; + + /* Chunk checksum is calculated for chunk ID (dword) and the actual + payload. */ + + real_cksum = htonl(crc32(0, in_buf + pos + 4, chunk_len + 4)); + + /* The in-file checksum is the last dword past the chunk data. */ + + file_cksum = *(uint32_t *)(in_buf + pos + 8 + chunk_len); + + /* If the checksums do not match, we need to fix the file. */ + + if (real_cksum != file_cksum) { + + /* First modification? Make a copy of the input buffer. Round size + up to 4 kB to minimize the number of reallocs needed. */ + + if (new_buf == in_buf) { + + if (len <= data->size) { + + new_buf = data->buf; + + } else { + + new_buf = realloc(data->buf, UP4K(len)); + if (!new_buf) { + + *out_buf = in_buf; + return len; + + } + + data->buf = new_buf; + data->size = UP4K(len); + memcpy(new_buf, in_buf, len); + + } + + } + + *(uint32_t *)(new_buf + pos + 8 + chunk_len) = real_cksum; + + } + + /* Skip the entire chunk and move to the next one. */ + + pos += 12 + chunk_len; + + } + + *out_buf = new_buf; + return len; + +} + +/* Gets called afterwards */ +void afl_custom_deinit(post_state_t *data) { + + free(data->buf); + free(data); + +} + diff --git a/custom_mutators/examples/simple-chunk-replace.py b/custom_mutators/examples/simple-chunk-replace.py new file mode 100644 index 00000000..c57218dd --- /dev/null +++ b/custom_mutators/examples/simple-chunk-replace.py @@ -0,0 +1,66 @@ +#!/usr/bin/env python +# encoding: utf-8 +""" +Simple Chunk Cross-Over Replacement Module for AFLFuzz + +@author: Christian Holler (:decoder) + +@license: + +This Source Code Form is subject to the terms of the Mozilla Public +License, v. 2.0. If a copy of the MPL was not distributed with this +file, You can obtain one at http://mozilla.org/MPL/2.0/. + +@contact: choller@mozilla.com +""" + +import random + + +def init(seed): + """ + Called once when AFLFuzz starts up. Used to seed our RNG. + + @type seed: int + @param seed: A 32-bit random value + """ + # Seed our RNG + random.seed(seed) + + +def fuzz(buf, add_buf, max_size): + """ + Called per fuzzing iteration. + + @type buf: bytearray + @param buf: The buffer that should be mutated. + + @type add_buf: bytearray + @param add_buf: A second buffer that can be used as mutation source. + + @type max_size: int + @param max_size: Maximum size of the mutated output. The mutation must not + produce data larger than max_size. + + @rtype: bytearray + @return: A new bytearray containing the mutated data + """ + # Make a copy of our input buffer for returning + ret = bytearray(buf) + + # Take a random fragment length between 2 and 32 (or less if add_buf is shorter) + fragment_len = random.randint(1, min(len(add_buf), 32)) + + # Determine a random source index where to take the data chunk from + rand_src_idx = random.randint(0, len(add_buf) - fragment_len) + + # Determine a random destination index where to put the data chunk + rand_dst_idx = random.randint(0, len(buf)) + + # Make the chunk replacement + ret[rand_dst_idx : rand_dst_idx + fragment_len] = add_buf[ + rand_src_idx : rand_src_idx + fragment_len + ] + + # Return data + return ret diff --git a/custom_mutators/examples/simple_example.c b/custom_mutators/examples/simple_example.c new file mode 100644 index 00000000..d888ec1f --- /dev/null +++ b/custom_mutators/examples/simple_example.c @@ -0,0 +1,74 @@ +// This simple example just creates random buffer <= 100 filled with 'A' +// needs -I /path/to/AFLplusplus/include +#include "custom_mutator_helpers.h" + +#include <stdint.h> +#include <stdlib.h> +#include <string.h> +#include <stdio.h> + +#ifndef _FIXED_CHAR + #define _FIXED_CHAR 0x41 +#endif + +typedef struct my_mutator { + + afl_t *afl; + + // Reused buffers: + BUF_VAR(u8, fuzz); + +} my_mutator_t; + +my_mutator_t *afl_custom_init(afl_t *afl, unsigned int seed) { + + srand(seed); + my_mutator_t *data = calloc(1, sizeof(my_mutator_t)); + if (!data) { + + perror("afl_custom_init alloc"); + return NULL; + + } + + data->afl = afl; + + return data; + +} + +size_t afl_custom_fuzz(my_mutator_t *data, uint8_t *buf, size_t buf_size, + u8 **out_buf, uint8_t *add_buf, + size_t add_buf_size, // add_buf can be NULL + size_t max_size) { + + int size = (rand() % 100) + 1; + if (size > max_size) size = max_size; + u8 *mutated_out = maybe_grow(BUF_PARAMS(data, fuzz), size); + if (!mutated_out) { + + *out_buf = NULL; + perror("custom mutator allocation (maybe_grow)"); + return 0; /* afl-fuzz will very likely error out after this. */ + + } + + memset(mutated_out, _FIXED_CHAR, size); + + *out_buf = mutated_out; + return size; + +} + +/** + * Deinitialize everything + * + * @param data The data ptr from afl_custom_init + */ +void afl_custom_deinit(my_mutator_t *data) { + + free(data->fuzz_buf); + free(data); + +} + diff --git a/custom_mutators/examples/wrapper_afl_min.py b/custom_mutators/examples/wrapper_afl_min.py new file mode 100644 index 00000000..5cd60031 --- /dev/null +++ b/custom_mutators/examples/wrapper_afl_min.py @@ -0,0 +1,123 @@ +#!/usr/bin/env python + +from XmlMutatorMin import XmlMutatorMin + +# Default settings (production mode) + +__mutator__ = None +__seed__ = "RANDOM" +__log__ = False +__log_file__ = "wrapper.log" + + +# AFL functions +def log(text): + """ + Logger + """ + + global __seed__ + global __log__ + global __log_file__ + + if __log__: + with open(__log_file__, "a") as logf: + logf.write("[%s] %s\n" % (__seed__, text)) + + +def init(seed): + """ + Called once when AFL starts up. Seed is used to identify the AFL instance in log files + """ + + global __mutator__ + global __seed__ + + # Get the seed + __seed__ = seed + + # Create a global mutation class + try: + __mutator__ = XmlMutatorMin(__seed__, verbose=__log__) + log("init(): Mutator created") + except RuntimeError as e: + log("init(): Can't create mutator: %s" % e.message) + + +def fuzz(buf, add_buf, max_size): + """ + Called for each fuzzing iteration. + """ + + global __mutator__ + + # Do we have a working mutator object? + if __mutator__ is None: + log("fuzz(): Can't fuzz, no mutator available") + return buf + + # Try to use the AFL buffer + via_buffer = True + + # Interpret the AFL buffer (an array of bytes) as a string + if via_buffer: + try: + buf_str = str(buf) + log("fuzz(): AFL buffer converted to a string") + except Exception: + via_buffer = False + log("fuzz(): Can't convert AFL buffer to a string") + + # Load XML from the AFL string + if via_buffer: + try: + __mutator__.init_from_string(buf_str) + log( + "fuzz(): Mutator successfully initialized with AFL buffer (%d bytes)" + % len(buf_str) + ) + except Exception: + via_buffer = False + log("fuzz(): Can't initialize mutator with AFL buffer") + + # If init from AFL buffer wasn't succesful + if not via_buffer: + log("fuzz(): Returning unmodified AFL buffer") + return buf + + # Sucessful initialization -> mutate + try: + __mutator__.mutate(max=5) + log("fuzz(): Input mutated") + except Exception: + log("fuzz(): Can't mutate input => returning buf") + return buf + + # Convert mutated data to a array of bytes + try: + data = bytearray(__mutator__.save_to_string()) + log("fuzz(): Mutated data converted as bytes") + except Exception: + log("fuzz(): Can't convert mutated data to bytes => returning buf") + return buf + + # Everything went fine, returning mutated content + log("fuzz(): Returning %d bytes" % len(data)) + return data + + +# Main (for debug) +if __name__ == "__main__": + + __log__ = True + __log_file__ = "/dev/stdout" + __seed__ = "RANDOM" + + init(__seed__) + + in_1 = bytearray( + "<foo ddd='eeee'>ffff<a b='c' d='456' eee='ffffff'>zzzzzzzzzzzz</a><b yyy='YYY' zzz='ZZZ'></b></foo>" + ) + in_2 = bytearray("<abc abc123='456' abcCBA='ppppppppppppppppppppppppppppp'/>") + out = fuzz(in_1, in_2) + print(out) diff --git a/custom_mutators/grammar_mutator/GRAMMAR_VERSION b/custom_mutators/grammar_mutator/GRAMMAR_VERSION index c7c1948d..3df8150e 100644 --- a/custom_mutators/grammar_mutator/GRAMMAR_VERSION +++ b/custom_mutators/grammar_mutator/GRAMMAR_VERSION @@ -1 +1 @@ -a2d4e4a +b79d51a diff --git a/custom_mutators/grammar_mutator/grammar_mutator b/custom_mutators/grammar_mutator/grammar_mutator -Subproject a2d4e4ab966f0581219fbb282f5ac8c89e85ead +Subproject b79d51a8daccbd7a693f9b6765c81ead14f28e2 |