--- a/macros.h	Tue Dec 20 00:50:16 2005 +0000
+++ b/macros.h	Tue Dec 20 20:52:05 2005 +0000
@@ -164,14 +164,4 @@
  */
 #define ALIGN(x, n) (((x) + (n) - 1) & ~((n) - 1))
 
-/* IS_INT_INSIDE = filter for ascii-function codes like BELL and so on [we need an special filter here later] */
-static inline bool IsValidAsciiChar(byte key)
-{
-	// XXX This filter stops certain crashes, but may be too restrictive.
-	return IS_INT_INSIDE(key, ' ', 127) ||
-		(IS_INT_INSIDE(key, 160, 256) &&
-		key != 0xAA && key != 0xAC && key != 0xAD && key != 0xAF &&
-		key != 0xB5 && key != 0xB6 && key != 0xB7 && key != 0xB9);
-}
-
 #endif /* MACROS_H */

--- a/network_gui.c	Tue Dec 20 00:50:16 2005 +0000
+++ b/network_gui.c	Tue Dec 20 20:52:05 2005 +0000
@@ -179,16 +179,12 @@
 			DrawString(260, y, STR_NETWORK_CLIENTS, 2); // clients on the server / maximum slots
 			y += 10;
 
-			if (sel->info.server_lang < NETWORK_NUM_LANGUAGES) {
-				SetDParam(0, STR_NETWORK_LANG_ANY + sel->info.server_lang);
-				DrawString(260, y, STR_NETWORK_LANGUAGE, 2); // server language
-			}
+			SetDParam(0, STR_NETWORK_LANG_ANY + sel->info.server_lang);
+			DrawString(260, y, STR_NETWORK_LANGUAGE, 2); // server language
 			y += 10;
 
-			if (sel->info.map_set < NUM_LANDSCAPE ) {
-				SetDParam(0, STR_TEMPERATE_LANDSCAPE + sel->info.map_set);
-				DrawString(260, y, STR_NETWORK_TILESET, 2); // tileset
-			}
+			SetDParam(0, STR_TEMPERATE_LANDSCAPE + sel->info.map_set);
+			DrawString(260, y, STR_NETWORK_TILESET, 2); // tileset
 			y += 10;
 
 			SetDParam(0, sel->info.map_width);
@@ -231,7 +227,7 @@
 
 	case WE_CLICK:
 		_selected_field = e->click.widget;
-		switch(e->click.widget) {
+		switch (e->click.widget) {
 		case 0: case 14: /* Close 'X' | Cancel button */
 			DeleteWindowById(WC_NETWORK_WINDOW, 0);
 			break;

--- a/network_udp.c	Tue Dec 20 00:50:16 2005 +0000
+++ b/network_udp.c	Tue Dec 20 20:52:05 2005 +0000
@@ -119,6 +119,12 @@
 		item->info.map_set       = NetworkRecv_uint8(&_udp_cs, p);
 		item->info.dedicated     = NetworkRecv_uint8(&_udp_cs, p);
 
+		str_validate(item->info.server_name);
+		str_validate(item->info.server_revision);
+		str_validate(item->info.map_name);
+		if (item->info.server_lang >= NETWORK_NUM_LANGUAGES) item->info.server_lang = 0;
+		if (item->info.map_set >= NUM_LANDSCAPE ) item->info.map_set = 0;
+
 		if (item->info.hostname[0] == '\0')
 			snprintf(item->info.hostname, sizeof(item->info.hostname), "%s", inet_ntoa(client_addr->sin_addr));
 	}

--- a/string.c	Tue Dec 20 00:50:16 2005 +0000
+++ b/string.c	Tue Dec 20 20:52:05 2005 +0000
@@ -57,3 +57,9 @@
 	if (p != NULL) memcpy(p, buf, len + 1);
 	return p;
 }
+
+void str_validate(char *str)
+{
+	for (; *str != '\0'; str++)
+		if (!IsValidAsciiChar(*str)) *str = '?';
+}

--- a/string.h	Tue Dec 20 00:50:16 2005 +0000
+++ b/string.h	Tue Dec 20 20:52:05 2005 +0000
@@ -25,4 +25,20 @@
 
 char* CDECL str_fmt(const char* str, ...);
 
+/** Scans the string for valid characters and if it finds invalid ones,
+ * replaces them with a question mark '?' */
+void str_validate(char *str);
+
+/** Only allow valid ascii-function codes. Filter special codes like BELL and
+ * so on [we need a special filter here later]
+ * @param key character to be checked
+ * @return true or false depending if the character is printable/valid or not */
+static inline bool IsValidAsciiChar(byte key)
+{
+	// XXX This filter stops certain crashes, but may be too restrictive.
+	return (key >= ' ' && key < 127) || (key >= 160 &&
+		key != 0xAA && key != 0xAC && key != 0xAD && key != 0xAF &&
+		key != 0xB5 && key != 0xB6 && key != 0xB7 && key != 0xB9);
+}
+
 #endif /* STRING_H */