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, 7 insertions, 6 deletions

diff --git a/fuzz/fuzz_ds_tree.cpp b/fuzz/fuzz_ds_tree.cpp
index ee00b1723..d06b5b19f 100644
--- a/fuzz/fuzz_ds_tree.cpp
+++ b/fuzz/fuzz_ds_tree.cpp
@@ -13,7 +13,7 @@ static int __compare(const void *a, const void *b)
   entry_a = (u_int32_t *)a;
   entry_b = (u_int32_t *)b;
 
-  return entry_a == entry_b ? 0 : (entry_a < entry_b ? -1 : +1);
+  return *entry_a == *entry_b ? 0 : (*entry_a < *entry_b ? -1 : +1);
 }
 static void __free(void * const node)
 {
@@ -22,15 +22,14 @@ static void __free(void * const node)
 }
 static void __walk(const void *a, ndpi_VISIT which, int depth, void *user_data)
 {
-  assert(user_data == NULL);
-  assert(a);
+  assert(user_data == NULL && a);
 }
 
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
   FuzzedDataProvider fuzzed_data(data, size);
   u_int16_t i, num_iteration, is_added = 0;
   void *root = NULL;
-  u_int32_t *entry, value_added, e;
+  u_int32_t *entry, value_added, e, *e2;
 
   /* Just to have some data */
   if (fuzzed_data.remaining_bytes() < 1024)
@@ -80,11 +79,13 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
   for (i = 0; i < num_iteration; i++) {
     e = fuzzed_data.ConsumeIntegral<u_int32_t>();
 
-    ndpi_tdelete(&e, &root, __compare);
+    e2 = (u_int32_t *)ndpi_tdelete(&e, &root, __compare);
+    ndpi_free(e2);
   }
   /* Delete of an added node */
   if (is_added) {
-    ndpi_tdelete(&value_added, &root, __compare);
+    e2 = (u_int32_t *)ndpi_tdelete(&value_added, &root, __compare);
+    ndpi_free(e2);
   }
 
   ndpi_twalk(root, __walk, NULL);