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afl-fuzz.c
10189 lines (6753 loc) · 274 KB
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afl-fuzz.c
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/*
Copyright 2013 Google LLC 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
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
/*
american fuzzy lop - fuzzer code
--------------------------------
Written and maintained by Michal Zalewski <lcamtuf@google.com>
Forkserver design by Jann Horn <jannhorn@googlemail.com>
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.
*/
#define AFL_MAIN
#include "android-ashmem.h"
#define MESSAGES_TO_STDOUT
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#define _FILE_OFFSET_BITS 64
#include "config.h"
#include "types.h"
#include "debug.h"
#include "alloc-inl.h"
#include "hash.h"
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <errno.h>
#include <signal.h>
#include <dirent.h>
#include <ctype.h>
#include <fcntl.h>
#include <termios.h>
#include <dlfcn.h>
#include <sched.h>
#include <sys/wait.h>
#include <sys/time.h>
#include <sys/shm.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/resource.h>
#include <sys/mman.h>
#include <sys/ioctl.h>
#include <sys/file.h>
#include <sys/capability.h>
#include "aflnet.h"
#include <graphviz/gvc.h>
#include <math.h>
//DIY
#include "afl_fusion.h"
//END OF DIY
#if defined(__APPLE__) || defined(__FreeBSD__) || defined (__OpenBSD__)
# include <sys/sysctl.h>
#endif /* __APPLE__ || __FreeBSD__ || __OpenBSD__ */
/* For systems that have sched_setaffinity; right now just Linux, but one
can hope... */
#ifdef __linux__
# define HAVE_AFFINITY 1
#endif /* __linux__ */
/* A toggle to export some variables when building as a library. Not very
useful for the general public. */
#ifdef AFL_LIB
# define EXP_ST
#else
# define EXP_ST static
#endif /* ^AFL_LIB */
/* Lots of globals, but mostly for the status UI and other things where it
really makes no sense to haul them around as function parameters. */
EXP_ST u8 *in_dir, /* Input directory with test cases */
*out_file, /* File to fuzz, if any */
*out_dir, /* Working & output directory */
*sync_dir, /* Synchronization directory */
*sync_id, /* Fuzzer ID */
*use_banner, /* Display banner */
*in_bitmap, /* Input bitmap */
*doc_path, /* Path to documentation dir */
*target_path, /* Path to target binary */
*orig_cmdline; /* Original command line */
EXP_ST u32 exec_tmout = EXEC_TIMEOUT; /* Configurable exec timeout (ms) */
static u32 hang_tmout = EXEC_TIMEOUT; /* Timeout used for hang det (ms) */
EXP_ST u64 mem_limit = MEM_LIMIT; /* Memory cap for child (MB) */
static u32 stats_update_freq = 1; /* Stats update frequency (execs) */
EXP_ST u8 skip_deterministic, /* Skip deterministic stages? */
force_deterministic, /* Force deterministic stages? */
use_splicing, /* Recombine input files? */
dumb_mode, /* Run in non-instrumented mode? */
score_changed, /* Scoring for favorites changed? */
kill_signal, /* Signal that killed the child */
resuming_fuzz, /* Resuming an older fuzzing job? */
timeout_given, /* Specific timeout given? */
not_on_tty, /* stdout is not a tty */
term_too_small, /* terminal dimensions too small */
uses_asan, /* Target uses ASAN? */
no_forkserver, /* Disable forkserver? */
crash_mode, /* Crash mode! Yeah! */
in_place_resume, /* Attempt in-place resume? */
auto_changed, /* Auto-generated tokens changed? */
no_cpu_meter_red, /* Feng shui on the status screen */
no_arith, /* Skip most arithmetic ops */
shuffle_queue, /* Shuffle input queue? */
bitmap_changed = 1, /* Time to update bitmap? */
qemu_mode, /* Running in QEMU mode? */
skip_requested, /* Skip request, via SIGUSR1 */
run_over10m, /* Run time over 10 minutes? */
persistent_mode, /* Running in persistent mode? */
deferred_mode, /* Deferred forkserver mode? */
fast_cal; /* Try to calibrate faster? */
static s32 out_fd, /* Persistent fd for out_file */
dev_urandom_fd = -1, /* Persistent fd for /dev/urandom */
dev_null_fd = -1, /* Persistent fd for /dev/null */
fsrv_ctl_fd, /* Fork server control pipe (write) */
fsrv_st_fd; /* Fork server status pipe (read) */
static s32 forksrv_pid, /* PID of the fork server */
child_pid = -1, /* PID of the fuzzed program */
out_dir_fd = -1; /* FD of the lock file */
EXP_ST u8* trace_bits; /* SHM with instrumentation bitmap */
EXP_ST u8 virgin_bits[MAP_SIZE], /* Regions yet untouched by fuzzing */
virgin_tmout[MAP_SIZE], /* Bits we haven't seen in tmouts */
virgin_crash[MAP_SIZE]; /* Bits we haven't seen in crashes */
static u8 var_bytes[MAP_SIZE]; /* Bytes that appear to be variable */
static s32 shm_id; /* ID of the SHM region */
static volatile u8 stop_soon, /* Ctrl-C pressed? */
clear_screen = 1, /* Window resized? */
child_timed_out; /* Traced process timed out? */
EXP_ST u32 queued_paths, /* Total number of queued testcases */
queued_variable, /* Testcases with variable behavior */
queued_at_start, /* Total number of initial inputs */
queued_discovered, /* Items discovered during this run */
queued_imported, /* Items imported via -S */
queued_favored, /* Paths deemed favorable */
queued_with_cov, /* Paths with new coverage bytes */
pending_not_fuzzed, /* Queued but not done yet */
pending_favored, /* Pending favored paths */
cur_skipped_paths, /* Abandoned inputs in cur cycle */
cur_depth, /* Current path depth */
max_depth, /* Max path depth */
useless_at_start, /* Number of useless starting paths */
var_byte_count, /* Bitmap bytes with var behavior */
current_entry, /* Current queue entry ID */
havoc_div = 1; /* Cycle count divisor for havoc */
EXP_ST u64 total_crashes, /* Total number of crashes */
unique_crashes, /* Crashes with unique signatures */
total_tmouts, /* Total number of timeouts */
unique_tmouts, /* Timeouts with unique signatures */
unique_hangs, /* Hangs with unique signatures */
total_execs, /* Total execve() calls */
slowest_exec_ms, /* Slowest testcase non hang in ms */
start_time, /* Unix start time (ms) */
last_path_time, /* Time for most recent path (ms) */
last_crash_time, /* Time for most recent crash (ms) */
last_hang_time, /* Time for most recent hang (ms) */
last_crash_execs, /* Exec counter at last crash */
queue_cycle, /* Queue round counter */
cycles_wo_finds, /* Cycles without any new paths */
trim_execs, /* Execs done to trim input files */
bytes_trim_in, /* Bytes coming into the trimmer */
bytes_trim_out, /* Bytes coming outa the trimmer */
blocks_eff_total, /* Blocks subject to effector maps */
blocks_eff_select; /* Blocks selected as fuzzable */
static u32 subseq_tmouts; /* Number of timeouts in a row */
static u8 *stage_name = "init", /* Name of the current fuzz stage */
*stage_short, /* Short stage name */
*syncing_party; /* Currently syncing with... */
static s32 stage_cur, stage_max; /* Stage progression */
static s32 splicing_with = -1; /* Splicing with which test case? */
static u32 master_id, master_max; /* Master instance job splitting */
static u32 syncing_case; /* Syncing with case #... */
static s32 stage_cur_byte, /* Byte offset of current stage op */
stage_cur_val; /* Value used for stage op */
static u8 stage_val_type; /* Value type (STAGE_VAL_*) */
static u64 stage_finds[32], /* Patterns found per fuzz stage */
stage_cycles[32]; /* Execs per fuzz stage */
static u32 rand_cnt; /* Random number counter */
static u64 total_cal_us, /* Total calibration time (us) */
total_cal_cycles; /* Total calibration cycles */
static u64 total_bitmap_size, /* Total bit count for all bitmaps */
total_bitmap_entries; /* Number of bitmaps counted */
static s32 cpu_core_count; /* CPU core count */
#ifdef HAVE_AFFINITY
static s32 cpu_aff = -1; /* Selected CPU core */
#endif /* HAVE_AFFINITY */
static FILE* plot_file; /* Gnuplot output file */
struct queue_entry {
u8* fname; /* File name for the test case */
u32 len; /* Input length */
u8 cal_failed, /* Calibration failed? */
trim_done, /* Trimmed? */
was_fuzzed, /* Had any fuzzing done yet? */
passed_det, /* Deterministic stages passed? */
has_new_cov, /* Triggers new coverage? */
var_behavior, /* Variable behavior? */
favored, /* Currently favored? */
fs_redundant; /* Marked as redundant in the fs? */
u32 bitmap_size, /* Number of bits set in bitmap */
exec_cksum; /* Checksum of the execution trace */
u64 exec_us, /* Execution time (us) */
handicap, /* Number of queue cycles behind */
depth; /* Path depth */
u8* trace_mini; /* Trace bytes, if kept */
u32 tc_ref; /* Trace bytes ref count */
struct queue_entry *next, /* Next element, if any */
*next_100; /* 100 elements ahead */
region_t *regions; /* Regions keeping information of message(s) sent to the server under test */
u32 region_count; /* Total number of regions in this seed */
u32 index; /* Index of this queue entry in the whole queue */
u32 generating_state_id; /* ID of the start at which the new seed was generated */
u8 is_initial_seed; /* Is this an initial seed */
u32 unique_state_count; /* Unique number of states traversed by this queue entry */
};
static struct queue_entry *queue, /* Fuzzing queue (linked list) */
*queue_cur, /* Current offset within the queue */
*queue_top, /* Top of the list */
*q_prev100; /* Previous 100 marker */
static struct queue_entry*
top_rated[MAP_SIZE]; /* Top entries for bitmap bytes */
struct extra_data {
u8* data; /* Dictionary token data */
u32 len; /* Dictionary token length */
u32 hit_cnt; /* Use count in the corpus */
};
static struct extra_data* extras; /* Extra tokens to fuzz with */
static u32 extras_cnt; /* Total number of tokens read */
static struct extra_data* a_extras; /* Automatically selected extras */
static u32 a_extras_cnt; /* Total number of tokens available */
static u8* (*post_handler)(u8* buf, u32* len);
/* Interesting values, as per config.h */
static s8 interesting_8[] = { INTERESTING_8 };
static s16 interesting_16[] = { INTERESTING_8, INTERESTING_16 };
static s32 interesting_32[] = { INTERESTING_8, INTERESTING_16, INTERESTING_32 };
/* Fuzzing stages */
enum {
/* 00 */ STAGE_FLIP1,
/* 01 */ STAGE_FLIP2,
/* 02 */ STAGE_FLIP4,
/* 03 */ STAGE_FLIP8,
/* 04 */ STAGE_FLIP16,
/* 05 */ STAGE_FLIP32,
/* 06 */ STAGE_ARITH8,
/* 07 */ STAGE_ARITH16,
/* 08 */ STAGE_ARITH32,
/* 09 */ STAGE_INTEREST8,
/* 10 */ STAGE_INTEREST16,
/* 11 */ STAGE_INTEREST32,
/* 12 */ STAGE_EXTRAS_UO,
/* 13 */ STAGE_EXTRAS_UI,
/* 14 */ STAGE_EXTRAS_AO,
/* 15 */ STAGE_HAVOC,
/* 16 */ STAGE_SPLICE
};
/* Stage value types */
enum {
/* 00 */ STAGE_VAL_NONE,
/* 01 */ STAGE_VAL_LE,
/* 02 */ STAGE_VAL_BE
};
/* Execution status fault codes */
enum {
/* 00 */ FAULT_NONE,
/* 01 */ FAULT_TMOUT,
/* 02 */ FAULT_CRASH,
/* 03 */ FAULT_ERROR,
/* 04 */ FAULT_NOINST,
/* 05 */ FAULT_NOBITS
};
char** use_argv; /* argument to run the target program. In vanilla AFL, this is a local variable in main. */
/* add these declarations here so we can call these functions earlier */
static u8 run_target(char** argv, u32 timeout);
static inline u32 UR(u32 limit);
static inline u8 has_new_bits(u8* virgin_map);
/* AFLNet-specific variables & functions */
u32 server_wait_usecs = 10000;
u32 poll_wait_msecs = 1;
u32 socket_timeout_usecs = 1000;
u8 net_protocol;
u8* net_ip;
u32 net_port;
char *response_buf = NULL;
int response_buf_size = 0; //the size of the whole response buffer
u32 *response_bytes = NULL; //an array keeping accumulated response buffer size
//e.g., response_bytes[i] keeps the response buffer size
//once messages 0->i have been received and processed by the SUT
u32 max_annotated_regions = 0;
u32 target_state_id = 0;
u32 *state_ids = NULL;
u32 state_ids_count = 0;
u32 selected_state_index = 0;
u32 state_cycles = 0;
u32 messages_sent = 0;
EXP_ST u8 session_virgin_bits[MAP_SIZE]; /* Regions yet untouched while the SUT is still running */
EXP_ST u8 *cleanup_script; /* script to clean up the environment of the SUT -- make fuzzing more deterministic */
EXP_ST u8 *netns_name; /* network namespace name to run server in */
char **was_fuzzed_map = NULL; /* A 2D array keeping state-specific was_fuzzed information */
u32 fuzzed_map_states = 0;
u32 fuzzed_map_qentries = 0;
u32 max_seed_region_count = 0;
u32 local_port; /* TCP/UDP port number to use as source */
/* flags */
u8 use_net = 0;
u8 poll_wait = 0;
u8 server_wait = 0;
u8 socket_timeout = 0;
u8 protocol_selected = 0;
u8 terminate_child = 0;
u8 corpus_read_or_sync = 0;
u8 state_aware_mode = 0;
u8 region_level_mutation = 0;
u8 state_selection_algo = ROUND_ROBIN, seed_selection_algo = RANDOM_SELECTION;
u8 false_negative_reduction = 0;
/* Implemented state machine */
Agraph_t *ipsm;
static FILE* ipsm_dot_file;
/* Hash table/map and list */
klist_t(lms) *kl_messages;
khash_t(hs32) *khs_ipsm_paths;
khash_t(hms) *khms_states;
//M2_prev points to the last message of M1 (i.e., prefix)
//If M1 is empty, M2_prev == NULL
//M2_next points to the first message of M3 (i.e., suffix)
//If M3 is empty, M2_next point to the end of the kl_messages linked list
kliter_t(lms) *M2_prev, *M2_next;
//Function pointers pointing to Protocol-specific functions
unsigned int* (*extract_response_codes)(unsigned char* buf, unsigned int buf_size, unsigned int* state_count_ref) = NULL;
region_t* (*extract_requests)(unsigned char* buf, unsigned int buf_size, unsigned int* region_count_ref) = NULL;
//DIY
int state_flag = 1;
struct queue_entry* tmp_q;
struct queue_entry* add_tmp_queue(u8* fname, u32 len, u8 passed_det);
static void add_q_to_queue(struct queue_entry *q);
static void add_to_queue(u8* fname, u32 len, u8 passed_det);
static void destroy_tmp_queue(struct queue_entry *q);
static void traverse_queue(char **argv);
void taint_mutation(char ** argv, u8 *in_buf, unsigned int in_buf_size);
// struct taint_queue *imp_taint_queue = NULL;
taint_header taint_headers;
struct taint_field *buf_msg_queue;
struct taint_field *cur_msg;
EXP_ST u8 *p_file;
EXP_ST u8 *err_kw_file;
EXP_ST u8 *taint_kw_file;
//END OF DIY
/* Initialize the implemented state machine as a graphviz graph */
void setup_ipsm()
{
ipsm = agopen("g", Agdirected, 0);
agattr(ipsm, AGNODE, "color", "black"); //Default node colr is black
agattr(ipsm, AGEDGE, "color", "black"); //Default edge color is black
khs_ipsm_paths = kh_init(hs32);
khms_states = kh_init(hms);
}
/* Free memory allocated to state-machine variables */
void destroy_ipsm()
{
agclose(ipsm);
kh_destroy(hs32, khs_ipsm_paths);
state_info_t *state;
kh_foreach_value(khms_states, state, {ck_free(state->seeds); ck_free(state);});
kh_destroy(hms, khms_states);
ck_free(state_ids);
}
/* Get state index in the state IDs list, given a state ID */
u32 get_state_index(u32 state_id) {
u32 index = 0;
for (index = 0; index < state_ids_count; index++) {
if (state_ids[index] == state_id) break;
}
return index;
}
/* Expand the size of the map when a new seed or a new state has been discovered */
void expand_was_fuzzed_map(u32 new_states, u32 new_qentries) {
int i, j;
//Realloc the memory
was_fuzzed_map = (char **)ck_realloc(was_fuzzed_map, (fuzzed_map_states + new_states) * sizeof(char *));
for (i = 0; i < fuzzed_map_states + new_states; i++)
was_fuzzed_map[i] = (char *)ck_realloc(was_fuzzed_map[i], (fuzzed_map_qentries + new_qentries) * sizeof(char));
//All new cells are marked as -1 -- meaning UNREACHABLE
//Keep other cells untouched
for (i = 0; i < fuzzed_map_states + new_states; i++)
for (j = 0; j < fuzzed_map_qentries + new_qentries; j++)
if ((i >= fuzzed_map_states) || (j >= fuzzed_map_qentries)) was_fuzzed_map[i][j] = -1;
//Update total number of states (rows) and total number of queue entries (columns) in the was_fuzzed_map
fuzzed_map_states += new_states;
fuzzed_map_qentries += new_qentries;
}
/* Get unique state count, given a state sequence */
u32 get_unique_state_count(unsigned int *state_sequence, unsigned int state_count) {
//A hash set is used so that no state is counted twice
khash_t(hs32) *khs_state_ids;
khs_state_ids = kh_init(hs32);
unsigned int discard, state_id, i;
u32 result = 0;
for (i = 0; i < state_count; i++) {
state_id = state_sequence[i];
if (kh_get(hs32, khs_state_ids, state_id) != kh_end(khs_state_ids)) {
continue;
} else {
kh_put(hs32, khs_state_ids, state_id, &discard);
result++;
}
}
kh_destroy(hs32, khs_state_ids);
return result;
}
/* Check if a state sequence is interesting (e.g., new state is discovered). Loop is taken into account */
u8 is_state_sequence_interesting(unsigned int *state_sequence, unsigned int state_count) {
//limit the loop count to only 1
u32 *trimmed_state_sequence = NULL;
u32 i, count = 0;
for (i=0; i < state_count; i++) {
if ((i >= 2) && (state_sequence[i] == state_sequence[i - 1]) && (state_sequence[i] == state_sequence[i - 2])
&& check_err_hash(state_sequence[i])) continue;
count++;
trimmed_state_sequence = (u32 *)realloc(trimmed_state_sequence, count * sizeof(unsigned int));
trimmed_state_sequence[count - 1] = state_sequence[i];
}
//Calculate the hash based on the shortened state sequence
u32 hashKey = hash32(trimmed_state_sequence, count * sizeof(unsigned int), 0);
if (trimmed_state_sequence) free(trimmed_state_sequence);
if (kh_get(hs32, khs_ipsm_paths, hashKey) != kh_end(khs_ipsm_paths)) {
return 0;
} else {
int dummy;
kh_put(hs32, khs_ipsm_paths, hashKey, &dummy);
return 1;
}
}
/* Update the annotations of regions (i.e., state sequence received from the server) */
void update_region_annotations(struct queue_entry* q)
{
u32 i = 0;
for (i = 0; i < messages_sent; i++) {
if ((response_bytes[i] == 0) || ( i > 0 && (response_bytes[i] - response_bytes[i - 1] == 0))) {
q->regions[i].state_sequence = NULL;
q->regions[i].state_count = 0;
} else {
unsigned int state_count;
q->regions[i].state_sequence = (*extract_response_codes)(response_buf, response_bytes[i], &state_count);
q->regions[i].state_count = state_count;
}
}
}
/* Choose a region data for region-level mutations */
u8* choose_source_region(u32 *out_len) {
u8 *out = NULL;
*out_len = 0;
struct queue_entry *q = queue;
//randomly select a seed
u32 index = UR(queued_paths);
while (index != 0) {
q = q->next;
index--;
}
//randomly select a region in the selected seed
if (q->region_count) {
u32 reg_index = UR(q->region_count);
u32 len = q->regions[reg_index].end_byte - q->regions[reg_index].start_byte + 1;
if (len <= MAX_FILE) {
out = (u8 *)ck_alloc(len);
if (out == NULL) PFATAL("Unable allocate a memory region to store a region");
*out_len = len;
//Read region data into memory. */
FILE *fp = fopen(q->fname, "rb");
fseek(fp, q->regions[reg_index].start_byte, SEEK_CUR);
fread(out, 1, len, fp);
fclose(fp);
}
}
return out;
}
/* Update #fuzzs visiting a specific state */
void update_fuzzs() {
unsigned int state_count, i, discard;
unsigned int *state_sequence = (*extract_response_codes)(response_buf, response_buf_size, &state_count);
//A hash set is used so that the #paths is not updated more than once for one specific state
khash_t(hs32) *khs_state_ids;
khint_t k;
khs_state_ids = kh_init(hs32);
for(i = 0; i < state_count; i++) {
unsigned int state_id = state_sequence[i];
if (kh_get(hs32, khs_state_ids, state_id) != kh_end(khs_state_ids)) {
continue;
} else {
kh_put(hs32, khs_state_ids, state_id, &discard);
k = kh_get(hms, khms_states, state_id);
if (k != kh_end(khms_states)) {
kh_val(khms_states, k)->fuzzs++;
}
}
}
ck_free(state_sequence);
kh_destroy(hs32, khs_state_ids);
}
/* Return the index of the "region" containing a given value */
u32 index_search(u32 *A, u32 n, u32 val) {
u32 index = 0;
for(index = 0; index < n; index++) {
if (val <= A[index]) break;
}
return index;
}
/* Calculate state scores and select the next state */
u32 update_scores_and_select_next_state(u8 mode) {
u32 result = 0, i;
if (state_ids_count == 0) return 0;
u32 *state_scores = NULL;
state_scores = (u32 *)ck_alloc(state_ids_count * sizeof(u32));
if (!state_scores) PFATAL("Cannot allocate memory for state_scores");
khint_t k;
state_info_t *state;
//Update the states' score
for(i = 0; i < state_ids_count; i++) {
u32 state_id = state_ids[i];
k = kh_get(hms, khms_states, state_id);
if (k != kh_end(khms_states)) {
state = kh_val(khms_states, k);
switch(mode) {
case FAVOR:
state->score = ceil(1000 * pow(2, -log10(log10(state->fuzzs + 1) * state->selected_times + 1)) * pow(2, log(state->paths_discovered + 1)));
break;
//other cases are reserved
}
if (i == 0) {
state_scores[i] = state->score;
} else {
state_scores[i] = state_scores[i-1] + state->score;
}
}
}
u32 randV = UR(state_scores[state_ids_count - 1]);
u32 idx = index_search(state_scores, state_ids_count, randV);
result = state_ids[idx];
if (state_scores) ck_free(state_scores);
return result;
}
/* Select a target state at which we do state-aware fuzzing */
unsigned int choose_target_state(u8 mode) {
u32 result = 0;
switch (mode) {
case RANDOM_SELECTION: //Random state selection
selected_state_index = UR(state_ids_count);
result = state_ids[selected_state_index];
break;
case ROUND_ROBIN: //Round-robin state selection
result = state_ids[selected_state_index];
selected_state_index++;
if (selected_state_index == state_ids_count) selected_state_index = 0;
break;
case FAVOR:
/* Do ROUND_ROBIN for a few cycles to get enough statistical information*/
if (state_cycles < 5) {
result = state_ids[selected_state_index];
selected_state_index++;
if (selected_state_index == state_ids_count) {
selected_state_index = 0;
state_cycles++;
}
break;
}
result = update_scores_and_select_next_state(FAVOR);
break;
default:
break;
}
return result;
}
/* Select a seed to exercise the target state */
struct queue_entry *choose_seed(u32 target_state_id, u8 mode)
{
khint_t k;
state_info_t *state;
struct queue_entry *result = NULL;
k = kh_get(hms, khms_states, target_state_id);
if (k != kh_end(khms_states)) {
state = kh_val(khms_states, k);
if (state->seeds_count == 0) return NULL;
switch (mode) {
case RANDOM_SELECTION: //Random seed selection
state->selected_seed_index = UR(state->seeds_count);
result = state->seeds[state->selected_seed_index];
break;
case ROUND_ROBIN: //Round-robin seed selection
result = state->seeds[state->selected_seed_index];
state->selected_seed_index++;
if (state->selected_seed_index == state->seeds_count) state->selected_seed_index = 0;
break;
case FAVOR:
if (state->seeds_count > 10) {
//Do seed selection similar to AFL + take into account state-aware information
//e.g., was_fuzzed information becomes state-aware
u32 passed_cycles = 0;
while (passed_cycles < 5) {
result = state->seeds[state->selected_seed_index];
if (state->selected_seed_index + 1 == state->seeds_count) {
state->selected_seed_index = 0;
passed_cycles++;
} else state->selected_seed_index++;
//Skip this seed with high probability if it is neither an initial seed nor a seed generated while the
//current target_state_id was targeted
if (result->generating_state_id != target_state_id && !result->is_initial_seed && UR(100) < 90) continue;
u32 target_state_index = get_state_index(target_state_id);
if (pending_favored) {
/* If we have any favored, non-fuzzed new arrivals in the queue,
possibly skip to them at the expense of already-fuzzed or non-favored
cases. */
if (((was_fuzzed_map[target_state_index][result->index] == 1) || !result->favored) && UR(100) < SKIP_TO_NEW_PROB) continue;
/* Otherwise, this seed is selected */
break;
} else if (!result->favored && queued_paths > 10) {
/* Otherwise, still possibly skip non-favored cases, albeit less often.
The odds of skipping stuff are higher for already-fuzzed inputs and
lower for never-fuzzed entries. */
if (queue_cycle > 1 && (was_fuzzed_map[target_state_index][result->index] == 0)) {
if (UR(100) < SKIP_NFAV_NEW_PROB) continue;
} else {
if (UR(100) < SKIP_NFAV_OLD_PROB) continue;
}
/* Otherwise, this seed is selected */
break;
}
}
} else {
//Do Round-robin if seeds_count of the selected state is small
result = state->seeds[state->selected_seed_index];
state->selected_seed_index++;
if (state->selected_seed_index == state->seeds_count) state->selected_seed_index = 0;
}
break;
default:
break;
}
} else {
PFATAL("AFLNet - the states hashtable has no entries for state %d", target_state_id);
}
return result;
}
/* Update state-aware variables */
void update_state_aware_variables(struct queue_entry *q, u8 dry_run)
{
khint_t k;
int discard, i;
state_info_t *state;
unsigned int state_count;
if (!response_buf_size || !response_bytes) return;
unsigned int *state_sequence = (*extract_response_codes)(response_buf, response_buf_size, &state_count);
q->unique_state_count = get_unique_state_count(state_sequence, state_count);
if (is_state_sequence_interesting(state_sequence, state_count)) {
//Save the current kl_messages to a file which can be used to replay the newly discovered paths on the ipsm
u8 *temp_str = state_sequence_to_string(state_sequence, state_count);
u8 *fname = alloc_printf("%s/replayable-new-ipsm-paths/id:%s:%s", out_dir, temp_str, dry_run ? basename(q->fname) : "new");
save_kl_messages_to_file(kl_messages, fname, 1, messages_sent);
ck_free(temp_str);
ck_free(fname);
//Update the IPSM graph
if (state_count > 1) {
unsigned int prevStateID = state_sequence[0];
for(i=1; i < state_count; i++) {
unsigned int curStateID = state_sequence[i];
char fromState[STATE_STR_LEN], toState[STATE_STR_LEN];
snprintf(fromState, STATE_STR_LEN, "%d", prevStateID);
snprintf(toState, STATE_STR_LEN, "%d", curStateID);
//Check if the prevStateID and curStateID have been added to the state machine as vertices
//Check also if the edge prevStateID->curStateID has been added
Agnode_t *from, *to;
Agedge_t *edge;
from = agnode(ipsm, fromState, FALSE);
if (!from) {
//Add a node to the graph
from = agnode(ipsm, fromState, TRUE);
if (dry_run) agset(from,"color","blue");
else agset(from,"color","red");
//Insert this newly discovered state into the states hashtable
state_info_t *newState_From = (state_info_t *) ck_alloc (sizeof(state_info_t));
newState_From->id = prevStateID;
newState_From->is_covered = 1;
newState_From->paths = 0;
newState_From->paths_discovered = 0;
newState_From->selected_times = 0;
newState_From->fuzzs = 0;
newState_From->score = 1;
newState_From->selected_seed_index = 0;
newState_From->seeds = NULL;
newState_From->seeds_count = 0;
k = kh_put(hms, khms_states, prevStateID, &discard);
kh_value(khms_states, k) = newState_From;
//Insert this into the state_ids array too
state_ids = (u32 *) ck_realloc(state_ids, (state_ids_count + 1) * sizeof(u32));
state_ids[state_ids_count++] = prevStateID;
if (prevStateID != 0) expand_was_fuzzed_map(1, 0);
}
to = agnode(ipsm, toState, FALSE);
if (!to) {
//Add a node to the graph
to = agnode(ipsm, toState, TRUE);
if (dry_run) agset(to,"color","blue");
else agset(to,"color","red");
//Insert this newly discovered state into the states hashtable
state_info_t *newState_To = (state_info_t *) ck_alloc (sizeof(state_info_t));
newState_To->id = curStateID;
newState_To->is_covered = 1;
newState_To->paths = 0;
newState_To->paths_discovered = 0;
newState_To->selected_times = 0;
newState_To->fuzzs = 0;
newState_To->score = 1;
newState_To->selected_seed_index = 0;
newState_To->seeds = NULL;
newState_To->seeds_count = 0;
k = kh_put(hms, khms_states, curStateID, &discard);
kh_value(khms_states, k) = newState_To;
//Insert this into the state_ids array too
state_ids = (u32 *) ck_realloc(state_ids, (state_ids_count + 1) * sizeof(u32));
state_ids[state_ids_count++] = curStateID;
if (curStateID != 0) expand_was_fuzzed_map(1, 0);
}
//Check if an edge from->to exists
edge = agedge(ipsm, from, to, NULL, FALSE);
if (!edge) {
//Add an edge to the graph
edge = agedge(ipsm, from, to, "new_edge", TRUE);
if (dry_run) agset(edge, "color", "blue");
else agset(edge, "color", "red");
}
//Update prevStateID
prevStateID = curStateID;
}
}
//Update the dot file
s32 fd;
u8* tmp;
tmp = alloc_printf("%s/ipsm.dot", out_dir);
fd = open(tmp, O_WRONLY | O_CREAT, 0600);
if (fd < 0) {
PFATAL("Unable to create %s", tmp);
} else {
ipsm_dot_file = fdopen(fd, "w");
agwrite(ipsm, ipsm_dot_file);
close(fileno(ipsm_dot_file));
ck_free(tmp);
}
}
//Update others no matter the new seed leads to interesting state sequence or not
//Annotate the regions
update_region_annotations(q);
//Update the states hashtable to keep the list of seeds which help us to reach a specific state
//Iterate over the regions & their annotated state (sub)sequences and update the hashtable accordingly
//All seed should "reach" state 0 (initial state) so we add this one to the map first
// fflush(stdout);
k = kh_get(hms, khms_states, 0);
if (k != kh_end(khms_states)) {
state = kh_val(khms_states, k);
state->seeds = (void **) ck_realloc (state->seeds, (state->seeds_count + 1) * sizeof(void *));
state->seeds[state->seeds_count] = (void *)q;
state->seeds_count++;
was_fuzzed_map[0][q->index] = 0; //Mark it as reachable but not fuzzed
} else {
PFATAL("AFLNet - the states hashtable should always contain an entry of the initial state");
}
//Now update other states
for(i = 0; i < q->region_count; i++) {
unsigned int regional_state_count = q->regions[i].state_count;
if (regional_state_count > 0) {
//reachable_state_id is the last ID in the state_sequence
unsigned int reachable_state_id = q->regions[i].state_sequence[regional_state_count - 1];
k = kh_get(hms, khms_states, reachable_state_id);
if (k != kh_end(khms_states)) {
state = kh_val(khms_states, k);
state->seeds = (void **) ck_realloc (state->seeds, (state->seeds_count + 1) * sizeof(void *));
state->seeds[state->seeds_count] = (void *)q;
state->seeds_count++;
} else {
//XXX. This branch is supposed to be not reachable
//However, due to some undeterminism, new state could be seen during regions' annotating process
//even though the state was not observed before
//To completely fix this, we should fix all causes leading to potential undeterminism
//For now, we just add the state into the hashtable
state_info_t *newState = (state_info_t *) ck_alloc (sizeof(state_info_t));
newState->id = reachable_state_id;
newState->is_covered = 1;
newState->paths = 0;
newState->paths_discovered = 0;
newState->selected_times = 0;
newState->fuzzs = 0;
newState->score = 1;
newState->selected_seed_index = 0;
newState->seeds = NULL;
newState->seeds = (void **) ck_realloc (newState->seeds, sizeof(void *));
newState->seeds[0] = (void *)q;
newState->seeds_count = 1;
k = kh_put(hms, khms_states, reachable_state_id, &discard);
kh_value(khms_states, k) = newState;
//Insert this into the state_ids array too
state_ids = (u32 *) ck_realloc(state_ids, (state_ids_count + 1) * sizeof(u32));
state_ids[state_ids_count++] = reachable_state_id;
if (reachable_state_id != 0) expand_was_fuzzed_map(1, 0);
}
was_fuzzed_map[get_state_index(reachable_state_id)][q->index] = 0; //Mark it as reachable but not fuzzed
}
}
//Update the number of paths which have traversed a specific state
//It can be used for calculating fuzzing energy
//A hash set is used so that the #paths is not updated more than once for one specific state
khash_t(hs32) *khs_state_ids;
khs_state_ids = kh_init(hs32);
for(i = 0; i < state_count; i++) {
unsigned int state_id = state_sequence[i];
if (kh_get(hs32, khs_state_ids, state_id) != kh_end(khs_state_ids)) {
continue;
} else {
kh_put(hs32, khs_state_ids, state_id, &discard);
k = kh_get(hms, khms_states, state_id);
if (k != kh_end(khms_states)) {
kh_val(khms_states, k)->paths++;
}
}
}
kh_destroy(hs32, khs_state_ids);