Fix some errors found by fuzzers (#2078)

Fix compilation on Windows.
"dirent.h" file has been taken from https://github.com/tronkko/dirent/

Fix Python bindings

Fix some warnings with x86_64-w64-mingw32-gcc:
```
protocols/dns.c: In function ‘ndpi_search_dns’:
protocols/dns.c:775:41: error: cast from pointer to integer of different size [-Werror=pointer-to-int-cast]
  775 |       unsigned long first_element_len = (unsigned long)dot - (unsigned long)_hostname;
      |                                         ^
protocols/dns.c:775:62: error: cast from pointer to integer of different size [-Werror=pointer-to-int-cast]
  775 |       unsigned long first_element_len = (unsigned long)dot - (unsigned long)_hostname;
      |
```
```
In file included from ndpi_bitmap64.c:31:
third_party/include/binaryfusefilter.h: In function ‘binary_fuse8_hash’:
third_party/include/binaryfusefilter.h:160:32: error: left shift count >= width of type [-Werror=shift-count-overflow]
  160 |     uint64_t hh = hash & ((1UL << 36) - 1);
```
```
In function ‘ndpi_match_custom_category’,
    inlined from ‘ndpi_fill_protocol_category.part.0’ at ndpi_main.c:7056:16:
ndpi_main.c:3419:3: error: ‘strncpy’ specified bound depends on the length of the source argument [-Werror=stringop-overflow=]
 3419 |   strncpy(buf, name, name_len);
```

6 files changed, 53 insertions, 19 deletions

diff --git a/src/include/ndpi_typedefs.h b/src/include/ndpi_typedefs.h
index 47e2b9897..d440a9e74 100644
--- a/src/include/ndpi_typedefs.h
+++ b/src/include/ndpi_typedefs.h
@@ -625,6 +625,19 @@ struct ndpi_flow_input_info {
   unsigned char seen_flow_beginning;
 };
 
+/* Save memory limiting the key to 56 bit */
+//#define SAVE_BINARY_BITMAP_MEMORY
+
+PACK_ON
+struct ndpi_binary_bitmap_entry {
+#ifdef SAVE_BINARY_BITMAP_MEMORY
+  u_int64_t value:56, category:8;
+#else
+  u_int64_t value;
+  u_int8_t category;
+#endif
+} PACK_OFF;
+
 /* ******************* ********************* ****************** */
 /* ************************************************************ */
 
@@ -1180,19 +1193,6 @@ typedef void ndpi_bitmap;
 typedef void ndpi_bitmap64;
 typedef void ndpi_bitmap_iterator;
 typedef void ndpi_filter;
-
-/* Save memory limiting the key to 56 bit */
-//#define SAVE_BINARY_BITMAP_MEMORY
-
-PACK_ON
-struct ndpi_binary_bitmap_entry {
-#ifdef SAVE_BINARY_BITMAP_MEMORY
-  u_int64_t value:56, category:8;
-#else
-  u_int64_t value;
-  u_int8_t category;
-#endif
-} PACK_OFF;
     
 typedef struct {
   u_int32_t num_allocated_entries, num_used_entries;
diff --git a/src/lib/ndpi_bitmap64.c b/src/lib/ndpi_bitmap64.c
index 1c8368b29..f254c1483 100644
--- a/src/lib/ndpi_bitmap64.c
+++ b/src/lib/ndpi_bitmap64.c
@@ -76,6 +76,9 @@ bool ndpi_bitmap64_compress(ndpi_bitmap64 *_b) {
   ndpi_bitmap64_t *b = (ndpi_bitmap64_t*)_b;
   u_int32_t i;
 
+  if(!b)
+    return(false);
+
   if(b->num_used_entries > 0) {
     if(b->num_used_entries > 1)
       qsort(b->entries, b->num_used_entries,
@@ -122,6 +125,9 @@ bool ndpi_bitmap64_compress(ndpi_bitmap64 *_b) {
 bool ndpi_bitmap64_set(ndpi_bitmap64 *_b, u_int64_t value) {
   ndpi_bitmap64_t *b = (ndpi_bitmap64_t*)_b;
 
+  if(!b)
+    return(false);
+
   if(b->is_compressed) {
     /*
       We need to discard the filter and start over as this
@@ -155,6 +161,9 @@ bool ndpi_bitmap64_set(ndpi_bitmap64 *_b, u_int64_t value) {
 bool ndpi_bitmap64_isset(ndpi_bitmap64 *_b, u_int64_t value) {
   ndpi_bitmap64_t *b = (ndpi_bitmap64_t*)_b;
 
+  if(!b)
+    return(false);
+
   if(!b->is_compressed) ndpi_bitmap64_compress(b);
 
   return(binary_fuse16_contain(value, &b->bitmap));
@@ -165,6 +174,9 @@ bool ndpi_bitmap64_isset(ndpi_bitmap64 *_b, u_int64_t value) {
 void ndpi_bitmap64_free(ndpi_bitmap64 *_b) {
   ndpi_bitmap64_t *b = (ndpi_bitmap64_t*)_b;
 
+  if(!b)
+    return;
+
   if(b->entries)        ndpi_free(b->entries);
 
   if(b->is_compressed)
@@ -178,5 +190,8 @@ void ndpi_bitmap64_free(ndpi_bitmap64 *_b) {
 u_int32_t ndpi_bitmap64_size(ndpi_bitmap64 *_b) {
   ndpi_bitmap64_t *b = (ndpi_bitmap64_t*)_b;
 
+  if(!b)
+    return(0);
+
   return(sizeof(ndpi_bitmap64) + binary_fuse16_size_in_bytes(&b->bitmap));
 }
diff --git a/src/lib/ndpi_domain_classify.c b/src/lib/ndpi_domain_classify.c
index fa866f32d..f1a319067 100644
--- a/src/lib/ndpi_domain_classify.c
+++ b/src/lib/ndpi_domain_classify.c
@@ -47,6 +47,9 @@ ndpi_domain_classify* ndpi_domain_classify_alloc() {
 void ndpi_domain_classify_free(ndpi_domain_classify *s) {
   u_int32_t i;
 
+  if(!s)
+    return;
+
   for(i=0; i<MAX_NUM_NDPI_DOMAIN_CLASSIFICATIONS; i++) {
     if(s->classes[i].domains != NULL) {
       ndpi_bitmap64_free(s->classes[i].domains);
@@ -90,6 +93,8 @@ bool ndpi_domain_classify_add(ndpi_domain_classify *s,
     } else if(s->classes[i].class_id == 0) {
       s->classes[i].class_id = class_id;
       s->classes[i].domains  = ndpi_bitmap64_alloc();
+      if(!s->classes[i].domains)
+        s->classes[i].class_id = 0;
       break;
     }
   }
@@ -117,6 +122,8 @@ u_int32_t ndpi_domain_classify_add_domains(ndpi_domain_classify *s,
     } else if(s->classes[i].class_id == 0) {
       s->classes[i].class_id = class_id;
       s->classes[i].domains  = ndpi_bitmap64_alloc();
+      if(!s->classes[i].domains)
+        s->classes[i].class_id = 0;
       break;
     }
   }
diff --git a/src/lib/ndpi_main.c b/src/lib/ndpi_main.c
index ae3c4c200..c2a5b2f2f 100644
--- a/src/lib/ndpi_main.c
+++ b/src/lib/ndpi_main.c
@@ -2669,7 +2669,8 @@ void ndpi_debug_printf(unsigned int proto, struct ndpi_detection_module_struct *
 
 void set_ndpi_debug_function(struct ndpi_detection_module_struct *ndpi_str, ndpi_debug_function_ptr ndpi_debug_printf) {
 #ifdef NDPI_ENABLE_DEBUG_MESSAGES
-  ndpi_str->ndpi_debug_printf = ndpi_debug_printf;
+  if(ndpi_str)
+    ndpi_str->ndpi_debug_printf = ndpi_debug_printf;
 #endif
 }
 
@@ -3002,7 +3003,15 @@ struct ndpi_detection_module_struct *ndpi_init_detection_module(ndpi_init_prefs
     ac_automata_name(ndpi_str->custom_categories.hostnames_shadow.ac_automa, "ccat_sh", 0);
 #else
   ndpi_str->custom_categories.sc_hostnames        = ndpi_domain_classify_alloc();
+  if(!ndpi_str->custom_categories.sc_hostnames) {
+    ndpi_exit_detection_module(ndpi_str);
+    return(NULL);
+  }
   ndpi_str->custom_categories.sc_hostnames_shadow = ndpi_domain_classify_alloc();
+  if(!ndpi_str->custom_categories.sc_hostnames_shadow) {
+    ndpi_exit_detection_module(ndpi_str);
+    return(NULL);
+  }
 #endif
 
   ndpi_str->custom_categories.ipAddresses = ndpi_patricia_new(32 /* IPv4 */);
@@ -3407,7 +3416,7 @@ int ndpi_match_custom_category(struct ndpi_detection_module_struct *ndpi_str,
   u_int max_len = sizeof(buf)-1;
     
   if(name_len > max_len) name_len = max_len;
-  strncpy(buf, name, name_len);
+  memcpy(buf, name, name_len);
   buf[name_len] = '\0';
   
   if(ndpi_domain_classify_contains(ndpi_str->custom_categories.sc_hostnames,
@@ -6887,6 +6896,9 @@ int ndpi_load_hostname_category(struct ndpi_detection_module_struct *ndpi_str,
 			       (AC_AUTOMATA_t *)ndpi_str->custom_categories.hostnames_shadow.ac_automa,
 			       name_to_add,category,category, 0, 0, 1); /* at_end */
 #else
+  if(ndpi_str->custom_categories.sc_hostnames_shadow == NULL)
+    return(-1);
+
   return(ndpi_domain_classify_add(ndpi_str->custom_categories.sc_hostnames_shadow,
 				  (u_int16_t)category, (char*)name_to_add) ? 0 : -1);
 #endif
diff --git a/src/lib/protocols/dns.c b/src/lib/protocols/dns.c
index 1a318aa02..b518ba0f2 100644
--- a/src/lib/protocols/dns.c
+++ b/src/lib/protocols/dns.c
@@ -772,7 +772,7 @@ static void ndpi_search_dns(struct ndpi_detection_module_struct *ndpi_struct, st
 
     dot = strchr(_hostname, '.');
     if(dot) {
-      unsigned long first_element_len = (unsigned long)dot - (unsigned long)_hostname;
+      uintptr_t first_element_len = dot - _hostname;
 
       if(first_element_len > 32) {
 	/*
diff --git a/src/lib/third_party/include/binaryfusefilter.h b/src/lib/third_party/include/binaryfusefilter.h
index 991e28c67..6e2498baa 100644
--- a/src/lib/third_party/include/binaryfusefilter.h
+++ b/src/lib/third_party/include/binaryfusefilter.h
@@ -157,7 +157,7 @@ static inline uint32_t binary_fuse8_hash(int index, uint64_t hash,
     uint64_t h = binary_fuse_mulhi(hash, filter->SegmentCountLength);
     h += index * filter->SegmentLength;
     // keep the lower 36 bits
-    uint64_t hh = hash & ((1UL << 36) - 1);
+    uint64_t hh = hash & ((1ULL << 36) - 1);
     // index 0: right shift by 36; index 1: right shift by 18; index 2: no shift
     h ^= (size_t)((hh >> (36 - 18 * index)) & filter->SegmentLengthMask);
     return h;
@@ -477,7 +477,7 @@ static inline uint32_t binary_fuse16_hash(int index, uint64_t hash,
     uint64_t h = binary_fuse_mulhi(hash, filter->SegmentCountLength);
     h += index * filter->SegmentLength;
     // keep the lower 36 bits
-    uint64_t hh = hash & ((1UL << 36) - 1);
+    uint64_t hh = hash & ((1ULL << 36) - 1);
     // index 0: right shift by 36; index 1: right shift by 18; index 2: no shift
     h ^= (size_t)((hh >> (36 - 18 * index)) & filter->SegmentLengthMask);
     return h;
@@ -522,7 +522,7 @@ static inline bool binary_fuse16_allocate(uint32_t size,
   filter->ArrayLength =
       (filter->SegmentCount + arity - 1) * filter->SegmentLength;
   filter->SegmentCountLength = filter->SegmentCount * filter->SegmentLength;
-  filter->Fingerprints = (uint16_t*)ndpi_malloc(filter->ArrayLength * sizeof(uint16_t));
+  filter->Fingerprints = (uint16_t*)ndpi_calloc(filter->ArrayLength, sizeof(uint16_t));
   return filter->Fingerprints != NULL;
 }