patch 8.2.1843: Netbeans: with huge buffer number memory allocation may fail

Problem:    Netbeans: with huge buffer number memory allocation may fail.
Solution:   Check for size overflow.

Author: brammool

src/netbeans.c

@@ -674,11 +674,19 @@ nb_get_buf(int bufno)
     {
 	if (bufno >= buf_list_size) // grow list
 	{
-	    nbbuf_T *t_buf_list = buf_list;
+	    nbbuf_T	*t_buf_list = buf_list;
+	    size_t	bufsize;
 
 	    incr = bufno - buf_list_size + 90;
 	    buf_list_size += incr;
-	    buf_list = vim_realloc(buf_list, buf_list_size * sizeof(nbbuf_T));
+	    bufsize = buf_list_size * sizeof(nbbuf_T);
+	    if (bufsize == 0 || bufsize / sizeof(nbbuf_T)
+						      != (size_t)buf_list_size)
+	    {
+		// list size overflow, bail out
+		return NULL;
+	    }
+	    buf_list = vim_realloc(buf_list, bufsize);
 	    if (buf_list == NULL)
 	    {
 		vim_free(t_buf_list);

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1843,
 /**/
     1842,
 /**/