Sanitize Usernames + Allow Extended ASCII In Sanitizer

libreborn/include/libreborn/minecraft.h

@@ -124,6 +124,17 @@ static uint32_t Minecraft_gui_property_offset = 0x198; // Gui
 
 static uint32_t CommandServer_minecraft_property_offset = 0x18; // Minecraft *
 
+// Packet
+
+typedef void (*Packet_read_t)(unsigned char *packet, unsigned char *bit_stream);
+
+// LoginPacket
+
+static Packet_read_t LoginPacket_read = (Packet_read_t) 0x6e5f8;
+static void *LoginPacket_read_vtable_addr = (void *) 0x108dcc;
+
+static uint32_t LoginPacket_username_property_offset = 0xc; // RakString
+
 // ChatPacket
 
 static uint32_t ChatPacket_message_property_offset = 0xc; // char *
@@ -293,6 +304,17 @@ static uint32_t ItemInstance_auxilary_property_offset = 0x8;
 typedef int32_t (*FillingContainer_addItem_t)(unsigned char *filling_container, unsigned char *item_instance);
 static FillingContainer_addItem_t FillingContainer_addItem = (FillingContainer_addItem_t) 0x92aa0;
 
+// RakNet::RakString
+
+typedef void (*RakNet_RakString_Assign_t)(unsigned char *rak_string, const char *str);
+static RakNet_RakString_Assign_t RakNet_RakString_Assign = (RakNet_RakString_Assign_t) 0xe9e34;
+
+static uint32_t RakNet_RakString_sharedString_property_offset = 0x0; // RakNet::RakString::SharedString *
+
+// RakNet::RakString::SharedString
+
+static uint32_t RakNet_RakString_SharedString_c_str_property_offset = 0x10; // char *
+
 // RakNetInstance
 
 typedef void (*RakNetInstance_send_t)(unsigned char *rak_net_instance, unsigned char *packet);
@@ -301,7 +323,7 @@ static uint32_t RakNetInstance_send_vtable_offset = 0x38;
 typedef uint32_t (*RakNetInstance_isServer_t)(unsigned char *rak_net_instance);
 static uint32_t RakNetInstance_isServer_vtable_offset = 0x48;
 
-static uint32_t RakNetInstance_peer_property_offset = 0x4;
+static uint32_t RakNetInstance_peer_property_offset = 0x4; // RakNet::RakPeer *
 
 // RakNet::RakPeer
 

libreborn/src/libreborn.c

@@ -212,8 +212,9 @@ void _patch_address(const char *file, int line, void *start, void *target) {
 }
 
 // Sanitize String
-#define MINIMUM_MESSAGE_CHARACTER 32
+#define MINIMUM_SAFE_CHARACTER 32
-#define MAXIMUM_MESSAGE_CHARACTER 126
+#define MAXIMUM_SAFE_CHARACTER 126
+#define MINIMUM_EXTENDED_SAFE_CHARACTER 128
 void sanitize_string(char **str, int max_length, unsigned int allow_newlines) {
     // Store Message Length
     int length = strlen(*str);
@@ -227,7 +228,7 @@ void sanitize_string(char **str, int max_length, unsigned int allow_newlines) {
         if (allow_newlines && ((*str)[i] == '\n' || (*str)[i] == '\r')) {
             continue;
         }
-        if ((*str)[i] < MINIMUM_MESSAGE_CHARACTER || (*str)[i] > MAXIMUM_MESSAGE_CHARACTER) {
+        if (((*str)[i] < MINIMUM_SAFE_CHARACTER || (*str)[i] > MAXIMUM_SAFE_CHARACTER) && (*str)[i] < MINIMUM_EXTENDED_SAFE_CHARACTER) {
             // Replace Illegal Character
             (*str)[i] = '?';
         }

mods/src/misc/misc.c

@@ -1,13 +1,18 @@
+#include <string.h>
+
 #include <libreborn/libreborn.h>
+#include <libreborn/minecraft.h>
 
 #include "../feature/feature.h"
 #include "misc.h"
 #include "../init/init.h"
 
-#include <libreborn/minecraft.h>
+// Minecraft Pi User Data Root
-
 #define NEW_PATH "/.minecraft-pi/"
 
+// Maximum Username Length
+#define MAX_USERNAME_LENGTH 16
+
 // Render Selected Item Text
 static void Gui_renderChatMessages_injection(unsigned char *gui, int32_t param_1, uint32_t param_2, uint32_t param_3, unsigned char *font) {
     // Call Original Method
@@ -40,6 +45,26 @@ static void Inventory_selectSlot_injection(unsigned char *inventory, int32_t slo
     reset_selected_item_text_timer = 1;
 }
 
+// Sanitize Username
+static void LoginPacket_read_injection(unsigned char *packet, unsigned char *bit_stream) {
+    // Call Original Method
+    (*LoginPacket_read)(packet, bit_stream);
+
+    // Prepare
+    unsigned char *rak_string = packet + LoginPacket_username_property_offset;
+    // Get Original Username
+    unsigned char *shared_string = *(unsigned char **) (rak_string + RakNet_RakString_sharedString_property_offset);
+    char *c_str = *(char **) (shared_string + RakNet_RakString_SharedString_c_str_property_offset);
+    // Sanitize
+    char *new_username = strdup(c_str);
+    ALLOC_CHECK(new_username);
+    sanitize_string(&new_username, MAX_USERNAME_LENGTH, 0);
+    // Set New Username
+    (*RakNet_RakString_Assign)(rak_string, new_username);
+    // Free
+    free(new_username);
+}
+
 void init_misc() {
     // Store Data In ~/.minecraft-pi Instead Of ~/.minecraft
     patch_address((void *) default_path, (void *) NEW_PATH);
@@ -55,6 +80,9 @@ void init_misc() {
     overwrite_calls((void *) Gui_tick, (void *) Gui_tick_injection);
     overwrite_calls((void *) Inventory_selectSlot, (void *) Inventory_selectSlot_injection);
 
+    // Sanitize Username
+    patch_address(LoginPacket_read_vtable_addr, (void *) LoginPacket_read_injection);
+
     // Init C++
     init_misc_cpp();
 }