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afl-analyze.c
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/*
american fuzzy lop - file format analyzer
-----------------------------------------
Written and maintained by Michal Zalewski <[email protected]>
Windows fork written by @_L4ys
Based on afl-showmap by Axel "0vercl0k" Souchet <[email protected]>
Copyright 2016, 2017 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
A nifty utility that grabs an input file and takes a stab at explaining
its structure by observing how changes to it affect the execution path.
If the output scrolls past the edge of the screen, pipe it to 'less -r'.
*/
#define _CRT_SECURE_NO_WARNINGS
#define _CRT_RAND_S
#define VERSION "2.52b"
#define AFL_MAIN
#include <windows.h>
#include "config.h"
#include "types.h"
#include "debug.h"
#include "alloc-inl.h"
#include "hash.h"
#include <io.h>
#include <direct.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <fcntl.h>
#include <ctype.h>
#include <sys/stat.h>
static s32 child_pid; /* PID of the tested program */
static HANDLE child_handle,
child_thread_handle;
static char *dynamorio_dir;
static char *client_params;
static CRITICAL_SECTION critical_section;
static u64 watchdog_timeout_time;
static u8 watchdog_enabled;
static u8 *target_cmd; /* command line of target */
static HANDLE shm_handle; /* Handle of the SHM region */
static HANDLE pipe_handle; /* Handle of the name pipe */
static u64 name_seed; /* Random integer to have a unique shm/pipe name */
static HANDLE devnul_handle; /* Handle of the nul device */
static u8 sinkhole_stds = 1; /* Sink-hole stdout/stderr messages?*/
static char *fuzzer_id = NULL; /* The fuzzer ID or a randomized
seed allowing multiple instances */
static u8* trace_bits; /* SHM with instrumentation bitmap */
static u8 *in_file, /* Analyzer input test case */
*prog_in, /* Targeted program input file */
*target_path, /* Path to target binary */
*doc_path; /* Path to docs */
static u8 *in_data; /* Input data for analysis */
static u32 in_len, /* Input data length */
orig_cksum, /* Original checksum */
total_execs, /* Total number of execs */
exec_hangs, /* Total number of hangs */
exec_tmout = EXEC_TIMEOUT; /* Exec timeout (ms) */
static u64 mem_limit = MEM_LIMIT; /* Memory limit (MB) */
static s32 shm_id, /* ID of the SHM region */
dev_null_fd = -1; /* FD to /dev/null */
static u8 edges_only, /* Ignore hit counts? */
use_hex_offsets, /* Show hex offsets? */
use_stdin = 1, /* Use stdin for program input? */
drioless = 0; /* Running without DRIO? */
static volatile u8
stop_soon, /* Ctrl-C pressed? */
child_timed_out; /* Child timed out? */
/* Constants used for describing byte behavior. */
#define RESP_NONE 0x00 /* Changing byte is a no-op. */
#define RESP_MINOR 0x01 /* Some changes have no effect. */
#define RESP_VARIABLE 0x02 /* Changes produce variable paths. */
#define RESP_FIXED 0x03 /* Changes produce fixed patterns. */
#define RESP_LEN 0x04 /* Potential length field */
#define RESP_CKSUM 0x05 /* Potential checksum */
#define RESP_SUSPECT 0x06 /* Potential "suspect" blob */
/* Classify tuple counts. This is a slow & naive version, but good enough here. */
#define AREP4(_sym) (_sym), (_sym), (_sym), (_sym)
#define AREP8(_sym) AREP4(_sym), AREP4(_sym)
#define AREP16(_sym) AREP8(_sym), AREP8(_sym)
#define AREP32(_sym) AREP16(_sym), AREP16(_sym)
#define AREP64(_sym) AREP32(_sym), AREP32(_sym)
#define AREP128(_sym) AREP64(_sym), AREP64(_sym)
static u8 count_class_lookup[256] = {
/* 0 - 3: 4 */ 0, 1, 2, 4,
/* 4 - 7: +4 */ AREP4(8),
/* 8 - 15: +8 */ AREP8(16),
/* 16 - 31: +16 */ AREP16(32),
/* 32 - 127: +96 */ AREP64(64), AREP32(64),
/* 128+: +128 */ AREP128(128)
};
static void classify_counts(u8* mem) {
u32 i = MAP_SIZE;
if (edges_only) {
while (i--) {
if (*mem) *mem = 1;
mem++;
}
} else {
while (i--) {
*mem = count_class_lookup[*mem];
mem++;
}
}
}
/* See if any bytes are set in the bitmap. */
static inline u8 anything_set(void) {
u32* ptr = (u32*)trace_bits;
u32 i = (MAP_SIZE >> 2);
while (i--) if (*(ptr++)) return 1;
return 0;
}
/* Get unix time in milliseconds */
static u64 get_cur_time(void) {
u64 ret;
FILETIME filetime;
GetSystemTimeAsFileTime(&filetime);
ret = (((u64)filetime.dwHighDateTime) << 32) + (u64)filetime.dwLowDateTime;
return ret / 10000;
}
char *alloc_printf(const char *_str, ...) {
va_list argptr;
char* _tmp;
s32 _len;
va_start(argptr, _str);
_len = vsnprintf(NULL, 0, _str, argptr);
if (_len < 0) FATAL("Whoa, snprintf() fails?!");
_tmp = ck_alloc(_len + 1);
vsnprintf(_tmp, (size_t)_len + 1, _str, argptr);
va_end(argptr);
return _tmp;
}
/* Get rid of shared memory and temp files (atexit handler). */
static void remove_shm(void) {
UnmapViewOfFile(trace_bits);
CloseHandle(shm_handle);
if (prog_in) _unlink(prog_in); /* Ignore errors */
}
/* Configure shared memory. */
static void setup_shm(void) {
char* shm_str = NULL;
unsigned int seeds[2];
u64 name_seed;
u8 attempts = 0;
while(attempts < 5) {
if(fuzzer_id == NULL) {
// If it is null, it means we have to generate a random seed to name the instance
rand_s(&seeds[0]);
rand_s(&seeds[1]);
name_seed = ((u64)seeds[0] << 32) | seeds[1];
fuzzer_id = (char *)alloc_printf("%I64x", name_seed);
}
shm_str = (char *)alloc_printf("afl_shm_%s", fuzzer_id);
shm_handle = CreateFileMapping(
INVALID_HANDLE_VALUE, // use paging file
NULL, // default security
PAGE_READWRITE, // read/write access
0, // maximum object size (high-order DWORD)
MAP_SIZE, // maximum object size (low-order DWORD)
(char *)shm_str); // name of mapping object
if(shm_handle == NULL) {
if(GetLastError() == ERROR_ALREADY_EXISTS) {
// We need another attempt to find a unique section name
attempts++;
ck_free(shm_str);
ck_free(fuzzer_id);
fuzzer_id = NULL;
continue;
}
else {
PFATAL("CreateFileMapping failed");
}
}
// We found a section name that works!
break;
}
if(attempts == 5) {
FATAL("Could not find a section name.\n");
}
atexit(remove_shm);
ck_free(shm_str);
trace_bits = (u8 *)MapViewOfFile(
shm_handle, // handle to map object
FILE_MAP_ALL_ACCESS, // read/write permission
0,
0,
MAP_SIZE
);
if (!trace_bits) PFATAL("MapViewOfFile() failed");
}
/* Read initial file. */
static void read_initial_file(void) {
struct stat st;
s32 fd = _open(in_file, O_RDONLY | O_BINARY);
if (fd < 0) PFATAL("Unable to open '%s'", in_file);
if (fstat(fd, &st) || !st.st_size)
FATAL("Zero-sized input file.");
if (st.st_size >= TMIN_MAX_FILE)
FATAL("Input file is too large (%u MB max)", TMIN_MAX_FILE / 1024 / 1024);
in_len = st.st_size;
in_data = ck_alloc_nozero(in_len);
ck_read(fd, in_data, in_len, in_file);
_close(fd);
OKF("Read %u byte%s from '%s'.", in_len, in_len == 1 ? "" : "s", in_file);
}
/* Write output file. */
static void write_to_file(u8* path, u8* mem, u32 len) {
s32 ret;
ret = _open(path, O_RDWR | O_CREAT | O_TRUNC | O_BINARY, DEFAULT_PERMISSION);
if (ret < 0) PFATAL("Unable to create '%s'", path);
ck_write(ret, mem, len, path);
_close(ret);
}
/* Handle timeout signal. */
/*static void handle_timeout(int sig) {
child_timed_out = 1;
if (child_pid > 0) kill(child_pid, SIGKILL);
}*/
//quoting on Windows is weird
size_t ArgvQuote(char *in, char *out) {
int needs_quoting = 0;
size_t size = 0;
char *p = in;
size_t i;
//check if quoting is necessary
if(strchr(in, ' ')) needs_quoting = 1;
if(strchr(in, '\"')) needs_quoting = 1;
if(strchr(in, '\t')) needs_quoting = 1;
if(strchr(in, '\n')) needs_quoting = 1;
if(strchr(in, '\v')) needs_quoting = 1;
if(!needs_quoting) {
size = strlen(in);
if(out) memcpy(out, in, size);
return size;
}
if(out) out[size] = '\"';
size++;
while(*p) {
size_t num_backslashes = 0;
while((*p) && (*p == '\\')) {
p++;
num_backslashes++;
}
if(*p == 0) {
for(i = 0; i < (num_backslashes*2); i++) {
if(out) out[size] = '\\';
size++;
}
break;
} else if(*p == '\"') {
for(i = 0; i < (num_backslashes*2 + 1); i++) {
if(out) out[size] = '\\';
size++;
}
if(out) out[size] = *p;
size++;
} else {
for(i = 0; i < num_backslashes; i++) {
if(out) out[size] = '\\';
size++;
}
if(out) out[size] = *p;
size++;
}
p++;
}
if(out) out[size] = '\"';
size++;
return size;
}
char *argv_to_cmd(char** argv) {
u32 len = 0, i;
u8* buf, *ret;
//todo shell-escape
for (i = 0; argv[i]; i++)
len += ArgvQuote(argv[i], NULL) + 1;
if(!len) FATAL("Error creating command line");
buf = ret = ck_alloc(len);
for (i = 0; argv[i]; i++) {
u32 l = ArgvQuote(argv[i], buf);
buf += l;
*(buf++) = ' ';
}
ret[len-1] = 0;
return ret;
}
static void create_target_process(char** argv) {
char* cmd;
char* pipe_name;
char *buf;
char *pidfile = NULL;
FILE *fp;
size_t pidsize;
BOOL inherit_handles = TRUE;
HANDLE hJob = NULL;
JOBOBJECT_EXTENDED_LIMIT_INFORMATION job_limit;
STARTUPINFO si;
PROCESS_INFORMATION pi;
pipe_name = (char *)alloc_printf("\\\\.\\pipe\\afl_pipe_%s", fuzzer_id);
pipe_handle = CreateNamedPipe(
pipe_name, // pipe name
PIPE_ACCESS_DUPLEX, // read/write access
0,
1, // max. instances
512, // output buffer size
512, // input buffer size
20000, // client time-out
NULL); // default security attribute
if (pipe_handle == INVALID_HANDLE_VALUE) {
FATAL("CreateNamedPipe failed, GLE=%d.\n", GetLastError());
}
target_cmd = argv_to_cmd(argv);
if (drioless) {
char *static_config = alloc_printf("%s:1", fuzzer_id);
if (static_config == NULL) {
FATAL("Cannot allocate static_config.");
}
SetEnvironmentVariable("AFL_STATIC_CONFIG", static_config);
cmd = alloc_printf("%s", target_cmd);
ck_free(static_config);
} else {
pidfile = alloc_printf("childpid_%s.txt", fuzzer_id);
cmd = alloc_printf(
"%s\\drrun.exe -pidfile %s -no_follow_children -c winafl.dll %s -fuzz_iterations 1 -fuzzer_id %s -- %s",
dynamorio_dir, pidfile, client_params, fuzzer_id, target_cmd
);
}
ZeroMemory(&si, sizeof(si));
si.cb = sizeof(si);
ZeroMemory(&pi, sizeof(pi));
if (sinkhole_stds) {
si.hStdOutput = si.hStdError = devnul_handle;
si.dwFlags |= STARTF_USESTDHANDLES;
} else {
inherit_handles = FALSE;
}
if (mem_limit != 0) {
hJob = CreateJobObject(NULL, NULL);
if (hJob == NULL) {
FATAL("CreateJobObject failed, GLE=%d.\n", GetLastError());
}
ZeroMemory(&job_limit, sizeof(job_limit));
job_limit.BasicLimitInformation.LimitFlags = JOB_OBJECT_LIMIT_PROCESS_MEMORY;
job_limit.ProcessMemoryLimit = mem_limit * 1024 * 1024;
if (!SetInformationJobObject(
hJob,
JobObjectExtendedLimitInformation,
&job_limit,
sizeof(job_limit)
)) {
FATAL("SetInformationJobObject failed, GLE=%d.\n", GetLastError());
}
}
if (!CreateProcess(NULL, cmd, NULL, NULL, inherit_handles, CREATE_SUSPENDED, NULL, NULL, &si, &pi)) {
FATAL("CreateProcess failed, GLE=%d.\n", GetLastError());
}
child_handle = pi.hProcess;
child_thread_handle = pi.hThread;
if (mem_limit != 0) {
if (!AssignProcessToJobObject(hJob, child_handle)) {
FATAL("AssignProcessToJobObject failed, GLE=%d.\n", GetLastError());
}
}
ResumeThread(child_thread_handle);
watchdog_timeout_time = get_cur_time() + exec_tmout;
watchdog_enabled = 1;
if (!ConnectNamedPipe(pipe_handle, NULL)) {
if (GetLastError() != ERROR_PIPE_CONNECTED) {
FATAL("ConnectNamedPipe failed, GLE=%d.\n", GetLastError());
}
}
watchdog_enabled = 0;
if (drioless == 0) {
//by the time pipe has connected the pidfile must have been created
fp = fopen(pidfile, "rb");
if (!fp) {
FATAL("Error opening pidfile.txt");
}
fseek(fp,0,SEEK_END);
pidsize = ftell(fp);
fseek(fp,0,SEEK_SET);
buf = (char *)malloc(pidsize+1);
if (!buf) {
FATAL("Error allocating %Iu bytes", pidsize + 1);
}
fread(buf, pidsize, 1, fp);
buf[pidsize] = 0;
fclose(fp);
remove(pidfile);
child_pid = atoi(buf);
free(buf);
ck_free(pidfile);
}
else {
child_pid = pi.dwProcessId;
}
ck_free(target_cmd);
ck_free(cmd);
ck_free(pipe_name);
}
static void destroy_target_process(int wait_exit) {
char* kill_cmd;
BOOL still_alive = TRUE;
STARTUPINFO si;
PROCESS_INFORMATION pi;
EnterCriticalSection(&critical_section);
if(!child_handle) {
goto leave;
}
if(WaitForSingleObject(child_handle, wait_exit) != WAIT_TIMEOUT) {
goto done;
}
// nudge the child process only if dynamorio is used
if(drioless) {
TerminateProcess(child_handle, 0);
} else {
kill_cmd = alloc_printf("%s\\drconfig.exe -nudge_pid %d 0 1", dynamorio_dir, child_pid);
ZeroMemory( &si, sizeof(si) );
si.cb = sizeof(si);
ZeroMemory( &pi, sizeof(pi) );
if(!CreateProcess(NULL, kill_cmd, NULL, NULL, FALSE, 0, NULL, NULL, &si, &pi)) {
FATAL("CreateProcess failed, GLE=%d.\n", GetLastError());
}
CloseHandle(pi.hProcess);
CloseHandle(pi.hThread);
ck_free(kill_cmd);
}
still_alive = WaitForSingleObject(child_handle, 2000) == WAIT_TIMEOUT;
if(still_alive) {
//wait until the child process exits
ZeroMemory( &si, sizeof(si) );
si.cb = sizeof(si);
ZeroMemory( &pi, sizeof(pi) );
kill_cmd = alloc_printf("taskkill /PID %d /F", child_pid);
if(!CreateProcess(NULL, kill_cmd, NULL, NULL, FALSE, 0, NULL, NULL, &si, &pi)) {
FATAL("CreateProcess failed, GLE=%d.\n", GetLastError());
}
CloseHandle(pi.hProcess);
CloseHandle(pi.hThread);
ck_free(kill_cmd);
if(WaitForSingleObject(child_handle, 20000) == WAIT_TIMEOUT) {
FATAL("Cannot kill child process\n");
}
}
done:
CloseHandle(child_handle);
CloseHandle(child_thread_handle);
child_handle = NULL;
child_thread_handle = NULL;
leave:
//close the pipe
if(pipe_handle) {
DisconnectNamedPipe(pipe_handle);
CloseHandle(pipe_handle);
pipe_handle = NULL;
}
LeaveCriticalSection(&critical_section);
}
DWORD WINAPI watchdog_timer( LPVOID lpParam ) {
u64 current_time;
while(1) {
Sleep(1000);
current_time = get_cur_time();
if(watchdog_enabled && (current_time > watchdog_timeout_time)) {
child_timed_out = 1;
destroy_target_process(0);
}
}
}
static void setup_watchdog_timer() {
watchdog_enabled = 0;
InitializeCriticalSection(&critical_section);
CreateThread(NULL, 0, watchdog_timer, 0, 0, NULL);
}
static int is_child_running() {
return (child_handle && (WaitForSingleObject(child_handle, 0 ) == WAIT_TIMEOUT));
}
/* Execute target application. Returns exec checksum, or 0 if program
times out. */
static u32 run_target(char** argv, u8* mem, u32 len, u8 first_run) {
int status = 0;
char command[] = "F";
DWORD num_read;
char result = 0;
u32 cksum;
memset(trace_bits, 0, MAP_SIZE);
MemoryBarrier();
write_to_file(prog_in, mem, len);
if (!is_child_running()) {
destroy_target_process(0);
create_target_process(argv);
}
child_timed_out = 0;
memset(trace_bits, 0, MAP_SIZE);
MemoryBarrier();
//TEMPORARY FIX FOR REGULAR USAGE OF AFL-TMIN
ReadFile(pipe_handle, &result, 1, &num_read, NULL);
if (result == 'K')
{
//a workaround for first cycle
ReadFile(pipe_handle, &result, 1, &num_read, NULL);
}
if (result != 'P')
{
FATAL("Unexpected result from pipe! expected 'P', instead received '%c'\n", result);
}
//END OF TEMPORARY FIX FOR REGULAR USAGE OF AFL-TMIN
WriteFile(
pipe_handle, // handle to pipe
command, // buffer to write from
1, // number of bytes to write
&num_read, // number of bytes written
NULL); // not overlapped I/O
watchdog_timeout_time = get_cur_time() + exec_tmout;
if (exec_tmout) {
watchdog_enabled = 1;
}
ReadFile(pipe_handle, &result, 1, &num_read, NULL);
if (exec_tmout) {
watchdog_enabled = 0;
}
MemoryBarrier();
/* Clean up bitmap, analyze exit condition, etc. */
classify_counts(trace_bits);
total_execs++;
destroy_target_process(2000);
if (stop_soon) {
SAYF(cRST cLRD "\n+++ Analysis aborted by user +++\n" cRST);
exit(1);
}
/* Always discard inputs that time out. */
if (child_timed_out) {
exec_hangs++;
return 0;
}
cksum = hash32(trace_bits, MAP_SIZE, HASH_CONST);
/* We don't actually care if the target is crashing or not,
except that when it does, the checksum should be different. */
cksum ^= 0xffffffff;
if (first_run) orig_cksum = cksum;
return cksum;
}
#ifdef USE_COLOR
/* Helper function to display a human-readable character. */
static void show_char(u8 val) {
if (val <= 32 || val >= 127)
SAYF("#%02x", val);
else
SAYF(" %c ", val);
}
/* Show the legend */
static void show_legend(void) {
SAYF(" " cLGR bgGRA " 01 " cRST " - no-op block "
cBLK bgLGN " 01 " cRST " - suspected length field\n"
" " cBRI bgGRA " 01 " cRST " - superficial content "
cBLK bgYEL " 01 " cRST " - suspected cksum or magic int\n"
" " cBLK bgCYA " 01 " cRST " - critical stream "
cBLK bgLRD " 01 " cRST " - suspected checksummed block\n"
" " cBLK bgMGN " 01 " cRST " - \"magic value\" section\n\n");
}
#endif /* USE_COLOR */
/* Interpret and report a pattern in the input file. */
static void dump_hex(u8* buf, u32 len, u8* b_data) {
u32 i;
for (i = 0; i < len; i++) {
#ifdef USE_COLOR
u32 rlen = 1, off;
#else
u32 rlen = 1;
#endif /* ^USE_COLOR */
u8 rtype = b_data[i] & 0x0f;
/* Look ahead to determine the length of run. */
while (i + rlen < len && (b_data[i] >> 7) == (b_data[i + rlen] >> 7)) {
if (rtype < (b_data[i + rlen] & 0x0f)) rtype = b_data[i + rlen] & 0x0f;
rlen++;
}
/* Try to do some further classification based on length & value. */
if (rtype == RESP_FIXED) {
switch (rlen) {
case 2: {
u16 val = *(u16*)(in_data + i);
/* Small integers may be length fields. */
if (val && (val <= in_len || SWAP16(val) <= in_len)) {
rtype = RESP_LEN;
break;
}
/* Uniform integers may be checksums. */
if (val && abs(in_data[i] - in_data[i + 1]) > 32) {
rtype = RESP_CKSUM;
break;
}
break;
}
case 4: {
u32 val = *(u32*)(in_data + i);
/* Small integers may be length fields. */
if (val && (val <= in_len || SWAP32(val) <= in_len)) {
rtype = RESP_LEN;
break;
}
/* Uniform integers may be checksums. */
if (val && (in_data[i] >> 7 != in_data[i + 1] >> 7 ||
in_data[i] >> 7 != in_data[i + 2] >> 7 ||
in_data[i] >> 7 != in_data[i + 3] >> 7)) {
rtype = RESP_CKSUM;
break;
}
break;
}
default:
if (rtype == 1 || rtype == 3 || (rtype >= 5 && rtype <= MAX_AUTO_EXTRA - 1))
break;
rtype = RESP_SUSPECT;
}
}
/* Print out the entire run. */
#ifdef USE_COLOR
for (off = 0; off < rlen; off++) {
/* Every 16 digits, display offset. */
if (!((i + off) % 16)) {
if (off) SAYF(cRST cLCY ">");
if (use_hex_offsets)
SAYF(cRST cGRA "%s[%06x] " cRST, (i + off) ? "\n" : "", i + off);
else
SAYF(cRST cGRA "%s[%06u] " cRST, (i + off) ? "\n" : "", i + off);
}
switch (rtype) {
case RESP_NONE: SAYF(cLGR bgGRA); break;
case RESP_MINOR: SAYF(cBRI bgGRA); break;
case RESP_VARIABLE: SAYF(cBLK bgCYA); break;
case RESP_FIXED: SAYF(cBLK bgMGN); break;
case RESP_LEN: SAYF(cBLK bgLGN); break;
case RESP_CKSUM: SAYF(cBLK bgYEL); break;
case RESP_SUSPECT: SAYF(cBLK bgLRD); break;
}
show_char(in_data[i + off]);
if (off != rlen - 1 && (i + off + 1) % 16) SAYF(" "); else SAYF(cRST " ");
}
#else
if (use_hex_offsets)
SAYF(" Offset %x, length %u: ", i, rlen);
else
SAYF(" Offset %u, length %u: ", i, rlen);
switch (rtype) {
case RESP_NONE: SAYF("no-op block\n"); break;
case RESP_MINOR: SAYF("superficial content\n"); break;
case RESP_VARIABLE: SAYF("critical stream\n"); break;
case RESP_FIXED: SAYF("\"magic value\" section\n"); break;
case RESP_LEN: SAYF("suspected length field\n"); break;
case RESP_CKSUM: SAYF("suspected cksum or magic int\n"); break;
case RESP_SUSPECT: SAYF("suspected checksummed block\n"); break;
}
#endif /* ^USE_COLOR */
i += rlen - 1;
}
#ifdef USE_COLOR
SAYF(cRST "\n");
#endif /* USE_COLOR */
}
/* Actually analyze! */
static void analyze(char** argv) {
u32 i;
u32 boring_len = 0, prev_xff = 0, prev_x01 = 0, prev_s10 = 0, prev_a10 = 0;
u8* b_data = ck_alloc(in_len + 1);
u8 seq_byte = 0;
b_data[in_len] = 0xff; /* Intentional terminator. */
ACTF("Analyzing input file (this may take a while)...\n");
#ifdef USE_COLOR
show_legend();
#endif /* USE_COLOR */
for (i = 0; i < in_len; i++) {
u32 xor_ff, xor_01, sub_10, add_10;
u8 xff_orig, x01_orig, s10_orig, a10_orig;
/* Perform walking byte adjustments across the file. We perform four
operations designed to elicit some response from the underlying
code. */
in_data[i] ^= 0xff;
xor_ff = run_target(argv, in_data, in_len, 0);
in_data[i] ^= 0xfe;
xor_01 = run_target(argv, in_data, in_len, 0);
in_data[i] = (in_data[i] ^ 0x01) - 0x10;
sub_10 = run_target(argv, in_data, in_len, 0);
in_data[i] += 0x20;
add_10 = run_target(argv, in_data, in_len, 0);
in_data[i] -= 0x10;
/* Classify current behavior. */
xff_orig = (xor_ff == orig_cksum);
x01_orig = (xor_01 == orig_cksum);
s10_orig = (sub_10 == orig_cksum);
a10_orig = (add_10 == orig_cksum);
if (xff_orig && x01_orig && s10_orig && a10_orig) {
b_data[i] = RESP_NONE;
boring_len++;
} else if (xff_orig || x01_orig || s10_orig || a10_orig) {
b_data[i] = RESP_MINOR;
boring_len++;
} else if (xor_ff == xor_01 && xor_ff == sub_10 && xor_ff == add_10) {