fuzz: some improvements and add two new fuzzers (#1881)

Remove `FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION` define from
`fuzz/Makefile.am`; it is already included by the main configure script
(when fuzzing).

Add a knob to force disabling of AESNI optimizations: this way we can
fuzz also no-aesni crypto code.

Move CRC32 algorithm into the library.

Add some fake traces to extend fuzzing coverage. Note that these traces
are hand-made (via scapy/curl) and must not be used as "proof" that the
dissectors are really able to identify this kind of traffic.

Some small updates to some dissectors:

CSGO: remove a wrong rule (never triggered, BTW). Any UDP packet starting
with "VS01" will be classified as STEAM (see steam.c around line 111).
Googling it, it seems right so.

XBOX: XBOX only analyses UDP flows while HTTP only TCP ones; therefore
that condition is false.

RTP, STUN: removed useless "break"s

Zattoo: `flow->zattoo_stage` is never set to any values greater or equal
to 5, so these checks are never true.

PPStream: `flow->l4.udp.ppstream_stage` is never read. Delete it.

TeamSpeak: we check for `flow->packet_counter == 3` just above, so the
following check `flow->packet_counter >= 3` is always false.

1 files changed, 0 insertions, 49 deletions

diff --git a/example/reader_util.c b/example/reader_util.c
index 62fa3046a..b1f72c650 100644
--- a/example/reader_util.c
+++ b/example/reader_util.c
@@ -2253,55 +2253,6 @@ struct ndpi_proto ndpi_workflow_process_packet(struct ndpi_workflow * workflow,
 			   flow_risk));
 }
 
-/* ********************************************************** */
-/*       http://home.thep.lu.se/~bjorn/crc/crc32_fast.c       */
-/* ********************************************************** */
-
-static uint32_t crc32_for_byte(uint32_t r) {
-  int j;
-  for(j = 0; j < 8; ++j)
-    r = ((r & 1) ? 0 : (uint32_t)0xEDB88320L) ^ r >> 1;
-  return r ^ (uint32_t)0xFF000000L;
-}
-
-/* Any unsigned integer type with at least 32 bits may be used as
- * accumulator type for fast crc32-calulation, but unsigned long is
- * probably the optimal choice for most systems. */
-typedef unsigned long accum_t;
-
-static void init_tables(uint32_t* table, uint32_t* wtable) {
-  size_t i, j, k, w;
-  for(i = 0; i < 0x100; ++i)
-    table[i] = crc32_for_byte(i);
-  for(k = 0; k < sizeof(accum_t); ++k)
-    for(i = 0; i < 0x100; ++i) {
-      for(j = w = 0; j < sizeof(accum_t); ++j)
-	w = table[(uint8_t)(j == k? w ^ i: w)] ^ w >> 8;
-      wtable[(k << 8) + i] = w ^ (k? wtable[0]: 0);
-    }
-}
-
-static void __crc32(const void* data, size_t n_bytes, uint32_t* crc) {
-  static uint32_t table[0x100], wtable[0x100*sizeof(accum_t)];
-  size_t n_accum = n_bytes/sizeof(accum_t);
-  size_t i, j;
-  if(!*table)
-    init_tables(table, wtable);
-  for(i = 0; i < n_accum; ++i) {
-    accum_t a = *crc ^ ((accum_t*)data)[i];
-    for(j = *crc = 0; j < sizeof(accum_t); ++j)
-      *crc ^= wtable[(j << 8) + (uint8_t)(a >> 8*j)];
-  }
-  for(i = n_accum*sizeof(accum_t); i < n_bytes; ++i)
-    *crc = table[(uint8_t)*crc ^ ((uint8_t*)data)[i]] ^ *crc >> 8;
-}
-
-u_int32_t ethernet_crc32(const void* data, size_t n_bytes) {
-  u_int32_t crc = 0;
-  __crc32(data, n_bytes, &crc);
-  return crc;
-}
-
 /* *********************************************** */
 
 #ifdef USE_DPDK