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AFLplusplus/custom_mutators/symqemu/symqemu.c
vanhauser-thc eec2c38a68 symqemu fix
2023-05-18 12:29:43 +02:00

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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;
static u32 found_items = 0;
#define SYMQEMU_LOCATION "symqemu"
#define DBG(x...) \
if (debug) { fprintf(stderr, x); }
typedef struct my_mutator {
afl_state_t *afl;
u32 all;
u32 late;
u8 *mutator_buf;
u8 *out_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")) {
WARNF(
"the symqemu module is not very effective 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);
snprintf(symqemu_path, len, "%s/%s", path_tmp, SYMQEMU_LOCATION);
snprintf(data->out_dir, len, "%s/out", symqemu_path, path_tmp);
(void)mkdir(symqemu_path, 0755);
(void)mkdir(data->out_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;
data->afl = afl;
data->seed = seed;
afl_struct = afl;
if (getenv("SYMQEMU_ALL")) { data->all = 1; }
if (getenv("SYMQEMU_LATE")) { data->late = 1; }
if (data->input_file) { setenv("SYMCC_INPUT_FILE", data->input_file, 1); }
DBG("out_dir=%s, target=%s, input_file=%s, argc=%u\n", data->out_dir,
data->target,
data->input_file ? (char *)data->input_file : (char *)"<stdin>",
data->argc);
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");
}
return data;
}
/* No need to receive a splicing item */
void afl_custom_splice_optout(void *data) {
(void)(data);
}
/* Get unix time in milliseconds */
inline u64 get_cur_time(void) {
struct timeval tv;
struct timezone tz;
gettimeofday(&tv, &tz);
return (tv.tv_sec * 1000ULL) + (tv.tv_usec / 1000);
}
u32 afl_custom_fuzz_count(my_mutator_t *data, const u8 *buf, size_t buf_size) {
if (likely((!afl_struct->queue_cur->favored && !data->all) ||
afl_struct->queue_cur->was_fuzzed)) {
return 0;
}
if (likely(data->late)) {
if (unlikely(get_cur_time() - afl_struct->last_find_time <=
10 * 60 * 1000)) {
return 0;
}
}
int pipefd[2];
struct stat st;
if (afl_struct->afl_env.afl_no_ui) {
ACTF("Sending to symqemu: %s", afl_struct->queue_cur->fname);
}
if (!(stat(afl_struct->queue_cur->fname, &st) == 0 && S_ISREG(st.st_mode) &&
st.st_size)) {
PFATAL("Couldn't find enqueued file: %s", afl_struct->queue_cur->fname);
}
if (afl_struct->fsrv.use_stdin) {
if (pipe(pipefd) == -1) {
PFATAL(
"Couldn't create a pipe for interacting with symqemu child process");
}
}
if (data->input_file) {
int fd = open(data->input_file, O_WRONLY | O_CREAT | O_TRUNC, 0644);
ssize_t s = write(fd, buf, buf_size);
close(fd);
DBG("wrote %zd/%zd to %s\n", s, buf_size, data->input_file);
}
int pid = fork();
if (pid == -1) return 0;
if (likely(pid)) {
if (!data->input_file || afl_struct->fsrv.use_stdin) {
close(pipefd[0]);
if (fcntl(pipefd[1], F_GETPIPE_SZ)) {
fcntl(pipefd[1], F_SETPIPE_SZ, MAX_FILE);
}
ck_write(pipefd[1], buf, buf_size, data->input_file);
close(pipefd[1]);
}
pid = waitpid(pid, NULL, 0);
DBG("symqemu finished executing!\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);
}
/* back in mother process */
struct dirent **nl;
s32 i, items = scandir(data->out_dir, &nl, NULL, NULL);
found_items = 0;
char source_name[4096];
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) {
++found_items;
}
free(nl[i]);
}
free(nl);
}
DBG("Done, found %u items!\n", found_items);
return found_items;
}
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) {
struct dirent **nl;
s32 done = 0, i, items = scandir(data->out_dir, &nl, NULL, NULL);
char source_name[4096];
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) {
int fd = open(source_name, O_RDONLY);
if (fd < 0) { goto got_an_issue; }
ssize_t r = read(fd, data->mutator_buf, MAX_FILE);
close(fd);
DBG("fn=%s, fd=%d, size=%ld\n", source_name, fd, r);
if (r < 1) { goto got_an_issue; }
done = 1;
--found_items;
unlink(source_name);
*out_buf = data->mutator_buf;
return (u32)r;
}
free(nl[i]);
}
free(nl);
}
got_an_issue:
*out_buf = NULL;
return 0;
}
/**
* 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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