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, 21 insertions, 14 deletions

diff --git a/fuzz/fuzz_alg_hll.cpp b/fuzz/fuzz_alg_hll.cpp
index 617968dfd..99603ce19 100644
--- a/fuzz/fuzz_alg_hll.cpp
+++ b/fuzz/fuzz_alg_hll.cpp
@@ -8,7 +8,8 @@
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
   FuzzedDataProvider fuzzed_data(data, size);
   u_int16_t i, num_iteration;
-  struct ndpi_hll hll;
+  struct ndpi_hll *hll;
+  int rc;
 
   /* Just to have some data */
   if(fuzzed_data.remaining_bytes() < 2048)
@@ -17,25 +18,31 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
   /* To allow memory allocation failures */
   fuzz_set_alloc_callbacks_and_seed(size);
 
-  ndpi_hll_init(&hll, fuzzed_data.ConsumeIntegral<u_int16_t>());
+  hll = (struct ndpi_hll *)ndpi_malloc(sizeof(*hll));
 
-  num_iteration = fuzzed_data.ConsumeIntegral<u_int8_t>();
-  for (i = 0; i < num_iteration; i++)
-    ndpi_hll_add_number(&hll, fuzzed_data.ConsumeIntegral<u_int32_t>());
+  rc = ndpi_hll_init(hll, fuzzed_data.ConsumeIntegral<u_int8_t>());
 
-  ndpi_hll_count(&hll);
+  if (rc == 0) {
+    num_iteration = fuzzed_data.ConsumeIntegral<u_int8_t>();
+    for (i = 0; i < num_iteration; i++)
+      ndpi_hll_add_number(hll, fuzzed_data.ConsumeIntegral<u_int32_t>());
 
-  ndpi_hll_reset(&hll);
+    ndpi_hll_count(hll);
 
-  num_iteration = fuzzed_data.ConsumeIntegral<u_int8_t>();
-  for (i = 0; i < num_iteration; i++) {
-    std::vector<int8_t>data = fuzzed_data.ConsumeBytes<int8_t>(fuzzed_data.ConsumeIntegral<u_int8_t>());
-    ndpi_hll_add(&hll, (char *)data.data(), data.size());
-  }
+    ndpi_hll_reset(hll);
+
+    num_iteration = fuzzed_data.ConsumeIntegral<u_int8_t>();
+    for (i = 0; i < num_iteration; i++) {
+      std::vector<int8_t>data = fuzzed_data.ConsumeBytes<int8_t>(fuzzed_data.ConsumeIntegral<u_int8_t>());
+      ndpi_hll_add(hll, (char *)data.data(), data.size());
+    }
 
-  ndpi_hll_count(&hll);
+    ndpi_hll_count(hll);
+
+    ndpi_hll_destroy(hll);
+  }
 
-  ndpi_hll_destroy(&hll);
+  ndpi_free(hll);
 
   return 0;
 }