oss-fuzz/projects/zlib/example_flush_fuzzer.c

121 lines
3.1 KiB
C

#include <stdio.h>
#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include <assert.h>
#include <stdlib.h>
#include <inttypes.h>
#include "zlib.h"
#define CHECK_ERR(err, msg) { \
if (err != Z_OK) { \
fprintf(stderr, "%s error: %d\n", msg, err); \
exit(1); \
} \
}
static const uint8_t *data;
static size_t dataLen;
static alloc_func zalloc = NULL;
static free_func zfree = NULL;
/* ===========================================================================
* Test deflate() with full flush
*/
void test_flush(unsigned char *compr, z_size_t *comprLen) {
z_stream c_stream; /* compression stream */
int err;
unsigned int len = dataLen;
c_stream.zalloc = zalloc;
c_stream.zfree = zfree;
c_stream.opaque = (void *)0;
err = deflateInit(&c_stream, Z_DEFAULT_COMPRESSION);
CHECK_ERR(err, "deflateInit");
c_stream.next_in = (Bytef *)data;
c_stream.next_out = compr;
c_stream.avail_in = 3;
c_stream.avail_out = (unsigned int)*comprLen;
err = deflate(&c_stream, Z_FULL_FLUSH);
CHECK_ERR(err, "deflate flush 1");
compr[3]++; /* force an error in first compressed block */
c_stream.avail_in = len - 3;
err = deflate(&c_stream, Z_FINISH);
if (err != Z_STREAM_END) {
CHECK_ERR(err, "deflate flush 2");
}
err = deflateEnd(&c_stream);
CHECK_ERR(err, "deflateEnd");
*comprLen = (z_size_t)c_stream.total_out;
}
/* ===========================================================================
* Test inflateSync()
*/
void test_sync(unsigned char *compr, size_t comprLen, unsigned char *uncompr,
size_t uncomprLen) {
int err;
z_stream d_stream; /* decompression stream */
d_stream.zalloc = zalloc;
d_stream.zfree = zfree;
d_stream.opaque = (void *)0;
d_stream.next_in = compr;
d_stream.avail_in = 2; /* just read the zlib header */
err = inflateInit(&d_stream);
CHECK_ERR(err, "inflateInit");
d_stream.next_out = uncompr;
d_stream.avail_out = (unsigned int)uncomprLen;
err = inflate(&d_stream, Z_NO_FLUSH);
CHECK_ERR(err, "inflate");
d_stream.avail_in = (unsigned int)comprLen - 2; /* read all compressed data */
err = inflateSync(&d_stream); /* but skip the damaged part */
CHECK_ERR(err, "inflateSync");
err = inflate(&d_stream, Z_FINISH);
if (err != Z_DATA_ERROR) {
fprintf(stderr, "inflate should report DATA_ERROR\n");
/* Because of incorrect adler32 */
exit(1);
}
err = inflateEnd(&d_stream);
CHECK_ERR(err, "inflateEnd");
}
int LLVMFuzzerTestOneInput(const uint8_t *d, size_t size) {
size_t comprLen = 100 + 2 * compressBound(size);
size_t uncomprLen = size;
uint8_t *compr, *uncompr;
/* Discard inputs larger than 1Mb. */
static size_t kMaxSize = 1024 * 1024;
// This test requires at least 3 bytes of input data.
if (size <= 3 || size > kMaxSize)
return 0;
data = d;
dataLen = size;
compr = (uint8_t *)calloc(1, comprLen);
uncompr = (uint8_t *)calloc(1, uncomprLen);
test_flush(compr, &comprLen);
test_sync(compr, comprLen, uncompr, uncomprLen);
free(compr);
free(uncompr);
/* This function must return 0. */
return 0;
}