Fixed dname functions not checking dname label length.

src/libknot/dname.c

@@ -267,6 +267,11 @@ static int knot_dname_find_labels(knot_dname_t *dname, int alloc)
 	short label_count = 0;
 
 	while (pos - name < size && *pos != '\0' && label_count < KNOT_MAX_DNAME_LABELS ) {
+		if (*pos > 63) { /* Check label lengths. */
+			dbg_dname("Wrong wire format of domain name!\n");
+			dbg_dname("Label %d exceeds 63 bytes.\n", label_count);
+			return -1;
+		}
 		labels[label_count++] = pos - name;
 		pos += *pos + 1;
 	}

src/libknot/zone/zone-contents.c

@@ -2164,7 +2164,7 @@ const knot_node_t *knot_zone_contents_find_previous_nsec3(
 
 static void knot_zone_contents_left_chop(char *name, size_t *size)
 {
-	short label_size = name[0];
+	short label_size = (unsigned char)name[0];
 	
 	memmove(name, name + label_size + 1, *size -label_size - 1);
 	*size = *size - label_size - 1;