From b51a2ac72a3cbd1b470890d0151a46da28e6754e Mon Sep 17 00:00:00 2001
From: Ivan Nardi <12729895+IvanNardi@users.noreply.github.com>
Date: Thu, 9 Feb 2023 20:02:12 +0100
Subject: 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.
---
 fuzz/fuzz_ndpi_reader.c | 8 ++++++++
 1 file changed, 8 insertions(+)

(limited to 'fuzz/fuzz_ndpi_reader.c')

diff --git a/fuzz/fuzz_ndpi_reader.c b/fuzz/fuzz_ndpi_reader.c
index 4546a549e..3ea222eff 100644
--- a/fuzz/fuzz_ndpi_reader.c
+++ b/fuzz/fuzz_ndpi_reader.c
@@ -24,6 +24,10 @@ int malloc_size_stats = 0;
 int max_malloc_bins = 0;
 struct ndpi_bin malloc_bins; /* unused */
 
+#ifdef CRYPT_FORCE_NO_AESNI
+extern int force_no_aesni;
+#endif
+
 FILE *bufferToFile(const uint8_t *Data, size_t Size) {
   FILE *fd;
   fd = tmpfile();
@@ -83,6 +87,10 @@ int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
     memset(workflow->stats.protocol_flows, 0,
 	   sizeof(workflow->stats.protocol_flows));
     ndpi_finalize_initialization(workflow->ndpi_struct);
+
+#ifdef CRYPT_FORCE_NO_AESNI
+    force_no_aesni = 1;
+#endif
   }
 
 #ifdef ENABLE_MEM_ALLOC_FAILURES
-- 
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