fuzz: add fuzzer testing nDPI (initial) configurations (#1830)

The goal of this fuzzer is to test init and deinit of the library, with
different configurations. In details:
* random memory allocation failures, even during init phase
* random `ndpi_init_prefs` parameter of `ndpi_init_detection_module()`
* random LRU caches sizes
* random bitmask of enabled protocols
* random parameters of `ndpi_set_detection_preferences()`
* random initialization of opportunistic TLS
* random load/don't load of configuration files

This new fuzzer is a C++ file, because it uses `FuzzedDataProvider`
class (see
https://github.com/google/fuzzing/blob/master/docs/split-inputs.md).
Note that the (existing) fuzzers need to be linked with C++ compiler
anyway, so this new fuzzer doesn't add any new requirements.

1 files changed, 11 insertions, 2 deletions

diff --git a/src/lib/ndpi_utils.c b/src/lib/ndpi_utils.c
index c7b2ff45a..990aef9bd 100644
--- a/src/lib/ndpi_utils.c
+++ b/src/lib/ndpi_utils.c
@@ -2309,6 +2309,9 @@ static u_int64_t ndpi_host_ip_risk_ptree_match(struct ndpi_detection_module_stru
   ndpi_prefix_t prefix;
   ndpi_patricia_node_t *node;
 
+  if(!ndpi_str->protocols_ptree)
+    return((u_int64_t)-1);
+
   /* Make sure all in network byte order otherwise compares wont work */
   ndpi_fill_prefix_v4(&prefix, pin, 32, ((ndpi_patricia_tree_t *) ndpi_str->protocols_ptree)->maxbits);
   node = ndpi_patricia_search_best(ndpi_str->ip_risk_mask_ptree, &prefix);
@@ -2642,10 +2645,16 @@ void load_common_alpns(struct ndpi_detection_module_struct *ndpi_str) {
 
     memset(&ac_pattern, 0, sizeof(ac_pattern));
     ac_pattern.astring      = ndpi_strdup((char*)common_alpns[i]);
+    if(!ac_pattern.astring) {
+      NDPI_LOG_ERR(ndpi_str, "Unable to add %s [mem alloc error]\n", common_alpns[i]);
+      continue;
+    }
     ac_pattern.length       = strlen(common_alpns[i]);
 
-    if(ac_automata_add(ndpi_str->common_alpns_automa.ac_automa, &ac_pattern) != ACERR_SUCCESS)
-      printf("%s(): unable to add %s\n", __FUNCTION__, common_alpns[i]);
+    if(ac_automata_add(ndpi_str->common_alpns_automa.ac_automa, &ac_pattern) != ACERR_SUCCESS) {
+      ndpi_free(ac_pattern.astring);
+      NDPI_LOG_ERR(ndpi_str, "Unable to add %s\n", common_alpns[i]);
+    }
   }
 }