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AFLplusplus/custom_mutators/autotokens/autotokens.cpp
vanhauser-thc 33f41e3974 autotokens: print stats at exit
2023-01-17 09:52:35 +01:00

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extern "C" {
#include "afl-fuzz.h"
}
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <iostream>
#include <fstream>
#include <unordered_map>
#include <vector>
#include <regex>
#define AUTOTOKENS_DEBUG 0
#define AUTOTOKENS_CHANGE_MIN 8
using namespace std;
typedef struct my_mutator {
afl_state *afl;
} my_mutator_t;
#define DEBUG \
if (unlikely(debug)) fprintf
static afl_state *afl_ptr;
static int debug = AUTOTOKENS_DEBUG;
static u32 current_id;
static u32 valid_structures;
static u32 whitespace_ids;
static u32 extras_cnt, a_extras_cnt;
static u64 all_spaces, all_tabs, all_lf, all_ws;
static u64 all_structure_items;
static unordered_map<string, vector<u32> *> file_mapping;
static unordered_map<string, u32> token_to_id;
static unordered_map<u32, string> id_to_token;
// static regex regex_comment_slash("(//.*)([\r\n]?)", regex::optimize);
static regex regex_comment_star("/\\*([:print:]|\n)*?\\*/",
regex::multiline | regex::optimize);
static regex regex_string("\"[[:print:]]*?\"|'[[:print:]]*?'", regex::optimize);
static vector<u32> *s; // the structure of the currently selected input
u32 good_whitespace_or_singleval() {
u32 i = rand_below(afl_ptr, current_id);
if (id_to_token[i].size() == 1) { return i; }
i = rand_below(afl_ptr, all_ws);
if (i < all_spaces) {
return 0;
} else if (i < all_tabs) {
return 1;
} else
return 2; // linefeed
}
extern "C" size_t afl_custom_fuzz(my_mutator_t *data, u8 *buf, size_t buf_size,
u8 **out_buf, u8 *add_buf,
size_t add_buf_size, size_t max_size) {
if (s == NULL) {
*out_buf = NULL;
return 0;
}
vector<u32> m = *s; // copy of the structure we will modify
u32 i, m_size = (u32)m.size();
u32 rounds =
MAX(AUTOTOKENS_CHANGE_MIN,
MIN(m_size >> 3, HAVOC_CYCLES * afl_ptr->queue_cur->perf_score *
afl_ptr->havoc_div / 256));
// DEBUG(stderr, "structure size: %lu, rounds: %u \n", m.size(), rounds);
u32 max_rand = 4;
for (i = 0; i < rounds; ++i) {
switch (rand_below(afl_ptr, max_rand)) {
/* CHANGE */
case 0: /* fall through */
case 1: {
u32 pos = rand_below(afl_ptr, m_size);
u32 cur_item = m[pos], new_item;
do {
new_item = rand_below(afl_ptr, current_id);
} while (unlikely(
new_item == cur_item ||
(whitespace_ids < new_item && whitespace_ids >= cur_item) ||
(whitespace_ids >= new_item && whitespace_ids < cur_item)));
DEBUG(stderr, "MUT: %u -> %u\n", cur_item, new_item);
m[pos] = new_item;
break;
}
/* INSERT (m_size +1 so we insert also after last place) */
case 2: {
u32 new_item;
do {
new_item = rand_below(afl_ptr, current_id);
} while (new_item >= whitespace_ids);
u32 pos = rand_below(afl_ptr, m_size + 1);
m.insert(m.begin() + pos, new_item);
++m_size;
// if we insert an identifier or string we might need whitespace
if (id_to_token[new_item].size() > 1) {
// need to insert before?
if (pos && m[pos - 1] >= whitespace_ids &&
id_to_token[m[pos - 1]].size() > 1) {
m.insert(m.begin() + pos, good_whitespace_or_singleval());
++m_size;
}
if (pos + 1 < m_size && m[pos + 1] >= whitespace_ids &&
id_to_token[m[pos + 1]].size() > 1) {
// need to insert after?
m.insert(m.begin() + pos + 1, good_whitespace_or_singleval());
++m_size;
}
}
break;
}
/* ERASE - only if large enough */
case 3: {
if (m_size > 8) {
m.erase(m.begin() + rand_below(afl_ptr, m_size));
--m_size;
} else {
max_rand = 3;
}
break;
}
// TODO: add full line insert splice, replace splace, delete
}
}
string output;
for (i = 0; i < m_size; ++i) {
output += id_to_token[m[i]];
}
u32 mutated_size = output.size();
u8 *mutated_out = (u8 *)afl_realloc((void **)out_buf, mutated_size);
if (unlikely(!mutated_out)) {
*out_buf = NULL;
return 0;
}
if (unlikely(debug)) {
DEBUG(stderr, "MUTATED to %u bytes:\n", mutated_size);
fwrite(output.data(), 1, mutated_size, stderr);
DEBUG(stderr, "\n---\n");
}
memcpy(mutated_out, output.data(), mutated_size);
*out_buf = mutated_out;
return mutated_size;
}
/* We are not using afl_custom_queue_new_entry() because not every corpus entry
will be necessarily fuzzed. so we use afl_custom_queue_get() instead */
extern "C" unsigned char afl_custom_queue_get(void *data,
const unsigned char *filename) {
if (likely(!debug)) {
if (afl_ptr->shm.cmplog_mode && !afl_ptr->queue_cur->is_ascii) {
s = NULL;
return 0;
}
}
// check if there are new dictionary entries and add them to the tokens
if (valid_structures) {
while (extras_cnt < afl_ptr->extras_cnt) {
u32 ok = 1, l = afl_ptr->extras[extras_cnt].len;
u8 *ptr = afl_ptr->extras[extras_cnt].data;
for (u32 i = 0; i < l; ++i) {
if (!isascii((int)ptr[i]) && !isprint((int)ptr[i])) {
ok = 0;
break;
}
}
if (ok) {
token_to_id[(char *)ptr] = current_id;
id_to_token[current_id] = (char *)ptr;
++current_id;
}
++extras_cnt;
DEBUG(stderr, "Added from dictionary: \"%s\"\n", ptr);
}
while (a_extras_cnt < afl_ptr->a_extras_cnt) {
u32 ok = 1, l = afl_ptr->a_extras[a_extras_cnt].len;
u8 *ptr = afl_ptr->a_extras[a_extras_cnt].data;
for (u32 i = 0; i < l; ++i) {
if (!isascii((int)ptr[i]) && !isprint((int)ptr[i])) {
ok = 0;
break;
}
}
if (ok) {
token_to_id[(char *)ptr] = current_id;
id_to_token[current_id] = (char *)ptr;
++current_id;
}
++a_extras_cnt;
DEBUG(stderr, "Added from auto dictionary: \"%s\"\n", ptr);
}
}
vector<u32> *structure = NULL;
string fn = (char *)filename;
auto entry = file_mapping.find(fn);
if (entry == file_mapping.end()) {
// this input file was not analyzed for tokens yet, so let's do it!
FILE *fp = fopen((char *)filename, "rb");
if (!fp) {
s = NULL;
return 0;
} // should not happen
fseek(fp, 0, SEEK_END);
size_t len = (size_t)ftell(fp);
if (len < AFL_TXT_MIN_LEN) {
fclose(fp);
file_mapping[fn] = structure; // NULL ptr so we don't read the file again
DEBUG(stderr, "Too short (%lu) %s\n", len, filename);
s = NULL;
return 0;
}
string input;
input.resize(len);
rewind(fp);
fread((void *)input.data(), input.size(), 1, fp);
fclose(fp);
if (!afl_ptr->shm.cmplog_mode) {
// not running with CMPLOG? bad choice, but whatever ...
// we only want text inputs, so we have to check it ourselves.
u32 valid_chars = 0;
for (u32 i = 0; i < len; ++i) {
if (isascii((int)input[i]) || isprint((int)input[i])) { ++valid_chars; }
}
// we want at least 95% of text characters ...
if (((len * AFL_TXT_MIN_PERCENT) / 100) > valid_chars) {
file_mapping[fn] = NULL;
DEBUG(stderr, "Not text (%lu) %s\n", len, filename);
s = NULL;
return 0;
}
}
// DEBUG(stderr, "Read %lu bytes for %s\nBefore comment trim:\n%s\n",
// input.size(), filename, input.c_str());
// input = regex_replace(input, regex_comment_slash, "$2");
input = regex_replace(input, regex_comment_star, "");
DEBUG(stderr, "After replace %lu bytes for %s\n%s\n", input.size(),
filename, input.c_str());
u32 spaces = count(input.begin(), input.end(), ' ');
u32 tabs = count(input.begin(), input.end(), '\t');
u32 linefeeds = count(input.begin(), input.end(), '\n');
bool ends_with_linefeed = input[input.length() - 1] == '\n';
DEBUG(stderr, "spaces=%u tabs=%u linefeeds=%u ends=%u\n", spaces, tabs,
linefeeds, ends_with_linefeed);
all_spaces += spaces;
all_tabs += tabs;
all_lf += linefeeds;
all_ws = all_spaces + all_tabs + all_lf;
// now extract all tokens
vector<string> tokens;
smatch match;
string::const_iterator cur = input.begin(), ende = input.end(), found, prev;
DEBUG(stderr, "START!\n");
while (regex_search(cur, ende, match, regex_string,
regex_constants::match_any |
regex_constants::match_not_null |
regex_constants::match_continuous)) {
prev = cur;
found = match[0].first;
cur = match[0].second;
DEBUG(stderr, "string %s found at start %lu offset %lu continue at %lu\n",
match[0].str().c_str(), prev - input.begin(), match.position(),
cur - input.begin());
if (prev < found) { // there are items between search start and find
while (prev < found) {
if (isspace(*prev)) {
auto start = prev;
while (isspace(*prev)) {
++prev;
}
tokens.push_back(std::string(start, prev));
DEBUG(stderr, "WHITESPACE %ld \"%s\"\n", prev - start,
tokens[tokens.size() - 1].c_str());
} else if (isalnum(*prev) || *prev == '$' || *prev == '_') {
auto start = prev;
while (isalnum(*prev) || *prev == '$' || *prev == '_' ||
*prev == '.' || *prev == '/') {
++prev;
}
tokens.push_back(std::string(start, prev));
DEBUG(stderr, "IDENTIFIER %ld \"%s\"\n", prev - start,
tokens[tokens.size() - 1].c_str());
} else {
tokens.push_back(std::string(prev, prev + 1));
DEBUG(stderr, "OTHER \"%c\"\n", *prev);
++prev;
}
}
}
if (match[0].length() > 0) { tokens.push_back(match[0]); }
}
DEBUG(stderr, "AFTER all strings\n");
if (cur < ende) {
while (cur < ende) {
if (isspace(*cur)) {
auto start = cur;
while (isspace(*cur)) {
++cur;
}
tokens.push_back(std::string(start, cur));
DEBUG(stderr, "WHITESPACE %ld \"%s\"\n", cur - start,
tokens[tokens.size() - 1].c_str());
} else if (isalnum(*cur) || *cur == '$' || *cur == '_') {
auto start = cur;
while (isalnum(*cur) || *cur == '$' || *cur == '_' || *cur == '.' ||
*cur == '/') {
++cur;
}
tokens.push_back(std::string(start, cur));
DEBUG(stderr, "IDENTIFIER %ld \"%s\"\n", cur - start,
tokens[tokens.size() - 1].c_str());
} else {
tokens.push_back(std::string(cur, cur + 1));
DEBUG(stderr, "OTHER \"%c\"\n", *cur);
++cur;
}
}
}
if (unlikely(debug)) {
DEBUG(stderr, "DUMPING TOKENS:\n");
for (u32 i = 0; i < tokens.size(); ++i) {
DEBUG(stderr, "%s", tokens[i].c_str());
}
DEBUG(stderr, "---------------------------\n");
}
/* Now we transform the tokens into an ID list and saved that */
structure = new vector<u32>();
u32 id;
for (u32 i = 0; i < tokens.size(); ++i) {
if ((id = token_to_id[tokens[i]]) == 0) {
// First time we see this token, add it to the list
token_to_id[tokens[i]] = current_id;
id_to_token[current_id] = tokens[i];
structure->push_back(current_id);
++current_id;
} else {
structure->push_back(id);
}
}
// save the token structure to the file mapping
file_mapping[fn] = structure;
s = structure;
++valid_structures;
all_structure_items += structure->size();
// we are done!
DEBUG(stderr, "DONE! We have %lu tokens in the structure\n",
structure->size());
} else {
if (entry->second == NULL) {
DEBUG(stderr, "Skipping %s\n", filename);
s = NULL;
return 0;
}
s = entry->second;
DEBUG(stderr, "OK %s\n", filename);
}
return 1; // we always fuzz unless non-ascii or too small
}
extern "C" my_mutator_t *afl_custom_init(afl_state *afl, unsigned int seed) {
(void)(seed);
my_mutator_t *data = (my_mutator_t *)calloc(1, sizeof(my_mutator_t));
if (!data) {
perror("afl_custom_init alloc");
return NULL;
}
data->afl = afl_ptr = afl;
// set common whitespace tokens
token_to_id[" "] = current_id;
id_to_token[current_id] = " ";
++current_id;
token_to_id["\t"] = current_id;
id_to_token[current_id] = "\t";
++current_id;
token_to_id["\n"] = current_id;
id_to_token[current_id] = "\n";
++current_id;
token_to_id["\r\n"] = current_id;
id_to_token[current_id] = "\r\n";
++current_id;
token_to_id[" \n"] = current_id;
id_to_token[current_id] = " \n";
++current_id;
token_to_id[" "] = current_id;
id_to_token[current_id] = " ";
++current_id;
token_to_id["\t\t"] = current_id;
id_to_token[current_id] = "\t\t";
++current_id;
whitespace_ids = current_id;
return data;
}
extern "C" void afl_custom_deinit(my_mutator_t *data) {
/* we use this to print statistics at exit :-)
needs to be stderr as stdout is filtered */
fprintf(stderr,
"\n\nAutotoken mutator statistics:\n"
" Number of all seen tokens: %lu\n"
" Number of input structures: %lu\n"
" Number of all items in structures: %lu\n\n",
current_id - 1, valid_structures, all_structure_items);
free(data);
}
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