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/* $OpenBSD: fuzz.c,v 1.8 2015/03/03 20:42:49 djm Exp $ */
/*
* Copyright (c) 2011 Damien Miller <djm@mindrot.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/* Utility functions/framework for fuzz tests */
#include "includes.h"
#include <sys/types.h>
#include <sys/uio.h>
#include <assert.h>
#include <ctype.h>
#include <stdio.h>
#ifdef HAVE_STDINT_H
# include <stdint.h>
#endif
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <unistd.h>
#include "test_helper.h"
#include "atomicio.h"
/* #define FUZZ_DEBUG */
#ifdef FUZZ_DEBUG
# define FUZZ_DBG(x) do { \
printf("%s:%d %s: ", __FILE__, __LINE__, __func__); \
printf x; \
printf("\n"); \
fflush(stdout); \
} while (0)
#else
# define FUZZ_DBG(x)
#endif
/* For brevity later */
typedef unsigned long long fuzz_ullong;
/* For base-64 fuzzing */
static const char fuzz_b64chars[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
struct fuzz {
/* Fuzz method currently in use */
int strategy;
/* Fuzz methods remaining */
int strategies;
/* Original seed data blob */
void *seed;
size_t slen;
/* Current working copy of seed with fuzz mutations applied */
u_char *fuzzed;
/* Used by fuzz methods */
size_t o1, o2;
};
static const char *
fuzz_ntop(u_int n)
{
switch (n) {
case 0:
return "NONE";
case FUZZ_1_BIT_FLIP:
return "FUZZ_1_BIT_FLIP";
case FUZZ_2_BIT_FLIP:
return "FUZZ_2_BIT_FLIP";
case FUZZ_1_BYTE_FLIP:
return "FUZZ_1_BYTE_FLIP";
case FUZZ_2_BYTE_FLIP:
return "FUZZ_2_BYTE_FLIP";
case FUZZ_TRUNCATE_START:
return "FUZZ_TRUNCATE_START";
case FUZZ_TRUNCATE_END:
return "FUZZ_TRUNCATE_END";
case FUZZ_BASE64:
return "FUZZ_BASE64";
default:
abort();
}
}
static int
fuzz_fmt(struct fuzz *fuzz, char *s, size_t n)
{
if (fuzz == NULL)
return -1;
switch (fuzz->strategy) {
case FUZZ_1_BIT_FLIP:
snprintf(s, n, "%s case %zu of %zu (bit: %zu)\n",
fuzz_ntop(fuzz->strategy),
fuzz->o1, fuzz->slen * 8, fuzz->o1);
return 0;
case FUZZ_2_BIT_FLIP:
snprintf(s, n, "%s case %llu of %llu (bits: %zu, %zu)\n",
fuzz_ntop(fuzz->strategy),
(((fuzz_ullong)fuzz->o2) * fuzz->slen * 8) + fuzz->o1,
((fuzz_ullong)fuzz->slen * 8) * fuzz->slen * 8,
fuzz->o1, fuzz->o2);
return 0;
case FUZZ_1_BYTE_FLIP:
snprintf(s, n, "%s case %zu of %zu (byte: %zu)\n",
fuzz_ntop(fuzz->strategy),
fuzz->o1, fuzz->slen, fuzz->o1);
return 0;
case FUZZ_2_BYTE_FLIP:
snprintf(s, n, "%s case %llu of %llu (bytes: %zu, %zu)\n",
fuzz_ntop(fuzz->strategy),
(((fuzz_ullong)fuzz->o2) * fuzz->slen) + fuzz->o1,
((fuzz_ullong)fuzz->slen) * fuzz->slen,
fuzz->o1, fuzz->o2);
return 0;
case FUZZ_TRUNCATE_START:
snprintf(s, n, "%s case %zu of %zu (offset: %zu)\n",
fuzz_ntop(fuzz->strategy),
fuzz->o1, fuzz->slen, fuzz->o1);
return 0;
case FUZZ_TRUNCATE_END:
snprintf(s, n, "%s case %zu of %zu (offset: %zu)\n",
fuzz_ntop(fuzz->strategy),
fuzz->o1, fuzz->slen, fuzz->o1);
return 0;
case FUZZ_BASE64:
assert(fuzz->o2 < sizeof(fuzz_b64chars) - 1);
snprintf(s, n, "%s case %llu of %llu (offset: %zu char: %c)\n",
fuzz_ntop(fuzz->strategy),
(fuzz->o1 * (fuzz_ullong)64) + fuzz->o2,
fuzz->slen * (fuzz_ullong)64, fuzz->o1,
fuzz_b64chars[fuzz->o2]);
return 0;
default:
return -1;
abort();
}
}
static void
dump(u_char *p, size_t len)
{
size_t i, j;
for (i = 0; i < len; i += 16) {
fprintf(stderr, "%.4zd: ", i);
for (j = i; j < i + 16; j++) {
if (j < len)
fprintf(stderr, "%02x ", p[j]);
else
fprintf(stderr, " ");
}
fprintf(stderr, " ");
for (j = i; j < i + 16; j++) {
if (j < len) {
if (isascii(p[j]) && isprint(p[j]))
fprintf(stderr, "%c", p[j]);
else
fprintf(stderr, ".");
}
}
fprintf(stderr, "\n");
}
}
void
fuzz_dump(struct fuzz *fuzz)
{
char buf[256];
if (fuzz_fmt(fuzz, buf, sizeof(buf)) != 0) {
fprintf(stderr, "%s: fuzz invalid\n", __func__);
abort();
}
fputs(buf, stderr);
fprintf(stderr, "fuzz original %p len = %zu\n", fuzz->seed, fuzz->slen);
dump(fuzz->seed, fuzz->slen);
fprintf(stderr, "fuzz context %p len = %zu\n", fuzz, fuzz_len(fuzz));
dump(fuzz_ptr(fuzz), fuzz_len(fuzz));
}
static struct fuzz *last_fuzz;
static void
siginfo(int unused __attribute__((__unused__)))
{
char buf[256];
test_info(buf, sizeof(buf));
atomicio(vwrite, STDERR_FILENO, buf, strlen(buf));
if (last_fuzz != NULL) {
fuzz_fmt(last_fuzz, buf, sizeof(buf));
atomicio(vwrite, STDERR_FILENO, buf, strlen(buf));
}
}
struct fuzz *
fuzz_begin(u_int strategies, const void *p, size_t l)
{
struct fuzz *ret = calloc(sizeof(*ret), 1);
assert(p != NULL);
assert(ret != NULL);
ret->seed = malloc(l);
assert(ret->seed != NULL);
memcpy(ret->seed, p, l);
ret->slen = l;
ret->strategies = strategies;
assert(ret->slen < SIZE_MAX / 8);
assert(ret->strategies <= (FUZZ_MAX|(FUZZ_MAX-1)));
FUZZ_DBG(("begin, ret = %p", ret));
fuzz_next(ret);
last_fuzz = ret;
#ifdef SIGINFO
signal(SIGINFO, siginfo);
#endif
signal(SIGUSR1, siginfo);
return ret;
}
void
fuzz_cleanup(struct fuzz *fuzz)
{
FUZZ_DBG(("cleanup, fuzz = %p", fuzz));
last_fuzz = NULL;
#ifdef SIGINFO
signal(SIGINFO, SIG_DFL);
#endif
signal(SIGUSR1, SIG_DFL);
assert(fuzz != NULL);
assert(fuzz->seed != NULL);
assert(fuzz->fuzzed != NULL);
free(fuzz->seed);
free(fuzz->fuzzed);
free(fuzz);
}
static int
fuzz_strategy_done(struct fuzz *fuzz)
{
FUZZ_DBG(("fuzz = %p, strategy = %s, o1 = %zu, o2 = %zu, slen = %zu",
fuzz, fuzz_ntop(fuzz->strategy), fuzz->o1, fuzz->o2, fuzz->slen));
switch (fuzz->strategy) {
case FUZZ_1_BIT_FLIP:
return fuzz->o1 >= fuzz->slen * 8;
case FUZZ_2_BIT_FLIP:
return fuzz->o2 >= fuzz->slen * 8;
case FUZZ_2_BYTE_FLIP:
return fuzz->o2 >= fuzz->slen;
case FUZZ_1_BYTE_FLIP:
case FUZZ_TRUNCATE_START:
case FUZZ_TRUNCATE_END:
case FUZZ_BASE64:
return fuzz->o1 >= fuzz->slen;
default:
abort();
}
}
void
fuzz_next(struct fuzz *fuzz)
{
u_int i;
FUZZ_DBG(("start, fuzz = %p, strategy = %s, strategies = 0x%lx, "
"o1 = %zu, o2 = %zu, slen = %zu", fuzz, fuzz_ntop(fuzz->strategy),
(u_long)fuzz->strategies, fuzz->o1, fuzz->o2, fuzz->slen));
if (fuzz->strategy == 0 || fuzz_strategy_done(fuzz)) {
/* If we are just starting out, we need to allocate too */
if (fuzz->fuzzed == NULL) {
FUZZ_DBG(("alloc"));
fuzz->fuzzed = calloc(fuzz->slen, 1);
}
/* Pick next strategy */
FUZZ_DBG(("advance"));
for (i = 1; i <= FUZZ_MAX; i <<= 1) {
if ((fuzz->strategies & i) != 0) {
fuzz->strategy = i;
break;
}
}
FUZZ_DBG(("selected = %u", fuzz->strategy));
if (fuzz->strategy == 0) {
FUZZ_DBG(("done, no more strategies"));
return;
}
fuzz->strategies &= ~(fuzz->strategy);
fuzz->o1 = fuzz->o2 = 0;
}
assert(fuzz->fuzzed != NULL);
switch (fuzz->strategy) {
case FUZZ_1_BIT_FLIP:
assert(fuzz->o1 / 8 < fuzz->slen);
memcpy(fuzz->fuzzed, fuzz->seed, fuzz->slen);
fuzz->fuzzed[fuzz->o1 / 8] ^= 1 << (fuzz->o1 % 8);
fuzz->o1++;
break;
case FUZZ_2_BIT_FLIP:
assert(fuzz->o1 / 8 < fuzz->slen);
assert(fuzz->o2 / 8 < fuzz->slen);
memcpy(fuzz->fuzzed, fuzz->seed, fuzz->slen);
fuzz->fuzzed[fuzz->o1 / 8] ^= 1 << (fuzz->o1 % 8);
fuzz->fuzzed[fuzz->o2 / 8] ^= 1 << (fuzz->o2 % 8);
fuzz->o1++;
if (fuzz->o1 >= fuzz->slen * 8) {
fuzz->o1 = 0;
fuzz->o2++;
}
break;
case FUZZ_1_BYTE_FLIP:
assert(fuzz->o1 < fuzz->slen);
memcpy(fuzz->fuzzed, fuzz->seed, fuzz->slen);
fuzz->fuzzed[fuzz->o1] ^= 0xff;
fuzz->o1++;
break;
case FUZZ_2_BYTE_FLIP:
assert(fuzz->o1 < fuzz->slen);
assert(fuzz->o2 < fuzz->slen);
memcpy(fuzz->fuzzed, fuzz->seed, fuzz->slen);
fuzz->fuzzed[fuzz->o1] ^= 0xff;
fuzz->fuzzed[fuzz->o2] ^= 0xff;
fuzz->o1++;
if (fuzz->o1 >= fuzz->slen) {
fuzz->o1 = 0;
fuzz->o2++;
}
break;
case FUZZ_TRUNCATE_START:
case FUZZ_TRUNCATE_END:
assert(fuzz->o1 < fuzz->slen);
memcpy(fuzz->fuzzed, fuzz->seed, fuzz->slen);
fuzz->o1++;
break;
case FUZZ_BASE64:
assert(fuzz->o1 < fuzz->slen);
assert(fuzz->o2 < sizeof(fuzz_b64chars) - 1);
memcpy(fuzz->fuzzed, fuzz->seed, fuzz->slen);
fuzz->fuzzed[fuzz->o1] = fuzz_b64chars[fuzz->o2];
fuzz->o2++;
if (fuzz->o2 >= sizeof(fuzz_b64chars) - 1) {
fuzz->o2 = 0;
fuzz->o1++;
}
break;
default:
abort();
}
FUZZ_DBG(("done, fuzz = %p, strategy = %s, strategies = 0x%lx, "
"o1 = %zu, o2 = %zu, slen = %zu", fuzz, fuzz_ntop(fuzz->strategy),
(u_long)fuzz->strategies, fuzz->o1, fuzz->o2, fuzz->slen));
}
int
fuzz_matches_original(struct fuzz *fuzz)
{
if (fuzz_len(fuzz) != fuzz->slen)
return 0;
return memcmp(fuzz_ptr(fuzz), fuzz->seed, fuzz->slen) == 0;
}
int
fuzz_done(struct fuzz *fuzz)
{
FUZZ_DBG(("fuzz = %p, strategies = 0x%lx", fuzz,
(u_long)fuzz->strategies));
return fuzz_strategy_done(fuzz) && fuzz->strategies == 0;
}
size_t
fuzz_len(struct fuzz *fuzz)
{
assert(fuzz->fuzzed != NULL);
switch (fuzz->strategy) {
case FUZZ_1_BIT_FLIP:
case FUZZ_2_BIT_FLIP:
case FUZZ_1_BYTE_FLIP:
case FUZZ_2_BYTE_FLIP:
case FUZZ_BASE64:
return fuzz->slen;
case FUZZ_TRUNCATE_START:
case FUZZ_TRUNCATE_END:
assert(fuzz->o1 <= fuzz->slen);
return fuzz->slen - fuzz->o1;
default:
abort();
}
}
u_char *
fuzz_ptr(struct fuzz *fuzz)
{
assert(fuzz->fuzzed != NULL);
switch (fuzz->strategy) {
case FUZZ_1_BIT_FLIP:
case FUZZ_2_BIT_FLIP:
case FUZZ_1_BYTE_FLIP:
case FUZZ_2_BYTE_FLIP:
case FUZZ_BASE64:
return fuzz->fuzzed;
case FUZZ_TRUNCATE_START:
assert(fuzz->o1 <= fuzz->slen);
return fuzz->fuzzed + fuzz->o1;
case FUZZ_TRUNCATE_END:
assert(fuzz->o1 <= fuzz->slen);
return fuzz->fuzzed;
default:
abort();
}
}