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AFLplusplus/custom_mutators/symqemu/symqemu.c
vanhauser-thc 1d0694df86 add symqemu custom mutator
2023-05-17 15:25:26 +02:00

447 lines
9.6 KiB
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#define _GNU_SOURCE
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <ctype.h>
#include "config.h"
#include "debug.h"
#include "afl-fuzz.h"
#include "common.h"
afl_state_t *afl_struct;
static u32 debug = 0;
#define DBG(x...) \
if (debug) { fprintf(stderr, x); }
typedef struct my_mutator {
afl_state_t *afl;
u8 *mutator_buf;
u8 *out_dir;
u8 *queue_dir;
u8 *target;
u8 *symqemu;
u8 *input_file;
u32 counter;
u32 seed;
u32 argc;
u8 **argv;
} my_mutator_t;
my_mutator_t *afl_custom_init(afl_state_t *afl, unsigned int seed) {
if (getenv("AFL_DEBUG")) debug = 1;
my_mutator_t *data = calloc(1, sizeof(my_mutator_t));
if (!data) {
perror("afl_custom_init alloc");
return NULL;
}
char *path = getenv("PATH");
char *exec_name = "symqemu-x86_64";
char *token = strtok(path, ":");
char exec_path[4096];
while (token != NULL && data->symqemu == NULL) {
snprintf(exec_path, sizeof(exec_path), "%s/%s", token, exec_name);
if (access(exec_path, X_OK) == 0) {
data->symqemu = (u8 *)strdup(exec_path);
break;
}
token = strtok(NULL, ":");
}
if (!data->symqemu) FATAL("symqemu binary %s not found", exec_name);
DBG("Found %s\n", data->symqemu);
if (getenv("AFL_CUSTOM_MUTATOR_ONLY"))
FATAL("the symqemu module cannot be used with AFL_CUSTOM_MUTATOR_ONLY.");
if ((data->mutator_buf = malloc(MAX_FILE)) == NULL) {
free(data);
perror("mutator_buf alloc");
return NULL;
}
data->target = getenv("AFL_CUSTOM_INFO_PROGRAM");
u8 *path_tmp = getenv("AFL_CUSTOM_INFO_OUT");
u32 len = strlen(path_tmp) + 32;
u8 *symqemu_path = malloc(len);
data->out_dir = malloc(len);
data->queue_dir = malloc(len);
snprintf(symqemu_path, len, "%s/../symqemu", path_tmp);
snprintf(data->out_dir, len, "%s/../symqemu/out", path_tmp);
snprintf(data->queue_dir, len, "%s/../symqemu/queue", path_tmp);
mkdir(symqemu_path, 0755);
mkdir(data->out_dir, 0755);
mkdir(data->queue_dir, 0755);
setenv("SYMCC_OUTPUT_DIR", data->out_dir, 1);
data->input_file = getenv("AFL_CUSTOM_INFO_PROGRAM_INPUT");
u8 *tmp = NULL;
if ((tmp = getenv("AFL_CUSTOM_INFO_PROGRAM_ARGV")) && *tmp) {
int argc = 0, index = 2;
for (u32 i = 0; i < strlen(tmp); ++i)
if (isspace(tmp[i])) ++argc;
data->argv = (u8 **)malloc((argc + 4) * sizeof(u8 **));
u8 *p = strdup(tmp);
do {
data->argv[index] = p;
while (*p && !isspace(*p))
++p;
if (*p) {
*p++ = 0;
while (isspace(*p))
++p;
}
if (strcmp(data->argv[index], "@@") == 0) {
if (!data->input_file) {
u32 ilen = strlen(symqemu_path) + 32;
data->input_file = malloc(ilen);
snprintf(data->input_file, ilen, "%s/.input", symqemu_path);
}
data->argv[index] = data->input_file;
}
DBG("%d: %s\n", index, data->argv[index]);
index++;
} while (*p);
data->argv[index] = NULL;
data->argc = index;
} else {
data->argv = (u8 **)malloc(8 * sizeof(u8 **));
data->argc = 2;
data->argv[2] = NULL;
}
data->argv[0] = data->symqemu;
data->argv[1] = data->target;
DBG("out_dir=%s, queue_dir=%s, target=%s, input_file=%s, argc=%u\n",
data->out_dir, data->queue_dir, data->target,
data->input_file ? (char *)data->input_file : (char *)"<stdin>",
data->argc);
if (data->input_file) { setenv("SYMCC_INPUT_FILE", data->input_file, 1); }
data->afl = afl;
data->seed = seed;
afl_struct = afl;
if (debug) {
fprintf(stderr, "[");
for (u32 i = 0; i <= data->argc; ++i)
fprintf(stderr, " \"%s\"",
data->argv[i] ? (char *)data->argv[i] : "<NULL>");
fprintf(stderr, " ]\n");
}
OKF("Custom mutator symqemu loaded - note that the initial startup of "
"afl-fuzz will be delayed the more starting seeds are present. This is "
"fine, do not worry!");
return data;
}
/* When a new queue entry is added we run this input with the symqemu
instrumented binary */
uint8_t afl_custom_queue_new_entry(my_mutator_t *data,
const uint8_t *filename_new_queue,
const uint8_t *filename_orig_queue) {
int pipefd[2];
struct stat st;
if (data->afl->afl_env.afl_no_ui)
ACTF("Sending to symqemu: %s", filename_new_queue);
u8 *fn = alloc_printf("%s", filename_new_queue);
if (!(stat(fn, &st) == 0 && S_ISREG(st.st_mode) && st.st_size)) {
ck_free(fn);
PFATAL("Couldn't find enqueued file: %s", fn);
}
if (afl_struct->fsrv.use_stdin) {
if (pipe(pipefd) == -1) {
ck_free(fn);
PFATAL(
"Couldn't create a pipe for interacting with symqemu child process");
}
}
int fd = open(fn, O_RDONLY);
if (fd < 0) return 0;
ssize_t r = read(fd, data->mutator_buf, MAX_FILE);
DBG("fn=%s, fd=%d, size=%ld\n", fn, fd, r);
ck_free(fn);
close(fd);
if (data->input_file) {
fd = open(data->input_file, O_WRONLY | O_CREAT | O_TRUNC, 0644);
ssize_t s = write(fd, data->mutator_buf, r);
close(fd);
DBG("wrote %zd/%zd to %s\n", s, r, data->input_file);
}
int pid = fork();
if (pid == -1) return 0;
if (pid) {
if (!data->input_file || afl_struct->fsrv.use_stdin) {
close(pipefd[0]);
if (fd >= 0) {
if (r <= 0) {
close(pipefd[1]);
return 0;
}
if (r > fcntl(pipefd[1], F_GETPIPE_SZ))
fcntl(pipefd[1], F_SETPIPE_SZ, MAX_FILE);
ck_write(pipefd[1], data->mutator_buf, r, filename_new_queue);
} else {
ck_free(fn);
close(pipefd[1]);
PFATAL(
"Something happened to the enqueued file before sending its "
"contents to symqemu binary");
}
close(pipefd[1]);
}
pid = waitpid(pid, NULL, 0);
DBG("symqemu finished executing!\n");
// At this point we need to transfer files to output dir, since their names
// collide and symqemu will just overwrite them
struct dirent **nl;
int32_t items = scandir(data->out_dir, &nl, NULL, NULL);
u8 *origin_name = basename(filename_new_queue);
u8 source_name[4096], destination_name[4096];
int32_t i;
if (items > 0) {
for (i = 0; i < (u32)items; ++i) {
// symqemu output files start with a digit
if (!isdigit(nl[i]->d_name[0])) continue;
struct stat st;
snprintf(source_name, sizeof(source_name), "%s/%s", data->out_dir,
nl[i]->d_name);
DBG("file=%s\n", source_name);
if (stat(source_name, &st) == 0 && S_ISREG(st.st_mode) && st.st_size) {
snprintf(destination_name, sizeof(destination_name), "%s/id:%06u,%s",
data->queue_dir, data->counter++, nl[i]->d_name);
DBG("src=%s dst=%s\n", source_name, destination_name);
rename(source_name, destination_name);
}
free(nl[i]);
}
free(nl);
}
DBG("Done!\n");
} else /* (pid == 0) */ { // child
if (afl_struct->fsrv.use_stdin) {
close(pipefd[1]);
dup2(pipefd[0], 0);
}
DBG("exec=%s\n", data->target);
if (!debug) {
close(1);
close(2);
dup2(afl_struct->fsrv.dev_null_fd, 1);
dup2(afl_struct->fsrv.dev_null_fd, 2);
}
execvp((char *)data->argv[0], (char **)data->argv);
fprintf(stderr, "Executing: [");
for (u32 i = 0; i <= data->argc; ++i)
fprintf(stderr, " \"%s\"",
data->argv[i] ? (char *)data->argv[i] : "<NULL>");
fprintf(stderr, " ]\n");
FATAL("Failed to execute %s %s\n", data->argv[0], data->argv[1]);
exit(-1);
}
return 0;
}
/*
uint32_t afl_custom_fuzz_count(my_mutator_t *data, const u8 *buf,
size_t buf_size) {
uint32_t count = 0, i;
struct dirent **nl;
int32_t items = scandir(data->out_dir, &nl, NULL, NULL);
if (items > 0) {
for (i = 0; i < (u32)items; ++i) {
struct stat st;
u8 * fn = alloc_printf("%s/%s", data->out_dir, nl[i]->d_name);
DBG("test=%s\n", fn);
if (stat(fn, &st) == 0 && S_ISREG(st.st_mode) && st.st_size) {
DBG("found=%s\n", fn);
count++;
}
ck_free(fn);
free(nl[i]);
}
free(nl);
}
DBG("dir=%s, count=%u\n", data->out_dir, count);
return count;
}
*/
// here we actually just read the files generated from symqemu
/*
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,
size_t max_size) {
struct dirent **nl;
int32_t i, done = 0, items = scandir(data->out_dir, &nl, NULL, NULL);
ssize_t size = 0;
if (items <= 0) return 0;
for (i = 0; i < (u32)items; ++i) {
struct stat st;
u8 * fn = alloc_printf("%s/%s", data->out_dir, nl[i]->d_name);
if (done == 0) {
if (stat(fn, &st) == 0 && S_ISREG(st.st_mode) && st.st_size) {
int fd = open(fn, O_RDONLY);
if (fd >= 0) {
size = read(fd, data->mutator_buf, max_size);
*out_buf = data->mutator_buf;
close(fd);
done = 1;
}
}
unlink(fn);
}
ck_free(fn);
free(nl[i]);
}
free(nl);
DBG("FUZZ size=%lu\n", size);
return (uint32_t)size;
}
*/
/**
* Deinitialize everything
*
* @param data The data ptr from afl_custom_init
*/
void afl_custom_deinit(my_mutator_t *data) {
free(data->mutator_buf);
free(data);
}
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