lz4/ossfuzz/decompress_fuzzer.c
Nick Terrell 3c40db8d25 [ossfuzz] Improve the fuzzers
* Run more decompression variants
* Round trip the compression fuzzer and do partial decompression as well
* Add a compression fuzzer that compresses into a smaller output buffer
  and test the destSize variant

These fuzzers caught 2 bugs that were fixed in the previous commit.
* Input buffer over-read in partial decompress
* Partial decompress fails if output size is 0
2019-07-15 12:22:04 -07:00

59 lines
2.1 KiB
C

/**
* This fuzz target attempts to decompress the fuzzed data with the simple
* decompression function to ensure the decompressor never crashes.
*/
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include "fuzz_helpers.h"
#include "lz4.h"
int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
{
uint32_t seed = FUZZ_seed(&data, &size);
size_t const dstCapacity = FUZZ_rand32(&seed, 0, 4 * size);
size_t const smallDictSize = size + 1;
size_t const largeDictSize = 64 * 1024 - 1;
size_t const dictSize = MAX(smallDictSize, largeDictSize);
char* const dst = (char*)malloc(dstCapacity);
char* const dict = (char*)malloc(dictSize + size);
char* const largeDict = dict;
char* const dataAfterDict = dict + dictSize;
char* const smallDict = dataAfterDict - smallDictSize;
FUZZ_ASSERT(dst);
FUZZ_ASSERT(dict);
/* Prepare the dictionary. The data doesn't matter for decompression. */
memset(dict, 0, dictSize);
memcpy(dataAfterDict, data, size);
/* Decompress using each possible dictionary configuration. */
/* No dictionary. */
LZ4_decompress_safe_usingDict((char const*)data, dst, size,
dstCapacity, NULL, 0);
/* Small external dictonary. */
LZ4_decompress_safe_usingDict((char const*)data, dst, size,
dstCapacity, smallDict, smallDictSize);
/* Large external dictionary. */
LZ4_decompress_safe_usingDict((char const*)data, dst, size,
dstCapacity, largeDict, largeDictSize);
/* Small prefix. */
LZ4_decompress_safe_usingDict((char const*)dataAfterDict, dst, size,
dstCapacity, smallDict, smallDictSize);
/* Large prefix. */
LZ4_decompress_safe_usingDict((char const*)data, dst, size,
dstCapacity, largeDict, largeDictSize);
/* Partial decompression. */
LZ4_decompress_safe_partial((char const*)data, dst, size,
dstCapacity, dstCapacity);
free(dst);
free(dict);
return 0;
}