From ecc56d4cbc2d958005c012f202704f89f58d073f Mon Sep 17 00:00:00 2001
From: FunkyFr3sh <cc.red.alert.1@googlemail.com>
Date: Fri, 20 Oct 2023 10:19:46 +0200
Subject: [PATCH] add some more error checks to IAT hooker

---
 inc/utils.h |  1 +
 src/hook.c  | 42 ++++++++++++++----------------------------
 src/utils.c | 25 +++++++++++++++++++++++++
 3 files changed, 40 insertions(+), 28 deletions(-)

diff --git a/inc/utils.h b/inc/utils.h
index fdb6b7f..4eee8a6 100644
--- a/inc/utils.h
+++ b/inc/utils.h
@@ -5,6 +5,7 @@
 #include <windows.h>
 
 
+BOOL util_is_bad_read_ptr(void* p);
 BOOL util_is_minimized(HWND hwnd);
 BOOL util_is_avx_supported();
 void util_limit_game_ticks();
diff --git a/src/hook.c b/src/hook.c
index 224e411..ba2ad7e 100644
--- a/src/hook.c
+++ b/src/hook.c
@@ -188,20 +188,23 @@ void hook_patch_obfuscated_iat_list(HMODULE hmod, BOOL unhook, HOOKLIST* hooks,
 
         while (import_desc->FirstThunk)
         {
+            if (!import_desc->Name)
+            {
+                import_desc++;
+                continue;
+            }
+
             for (int i = 0; hooks[i].module_name[0]; i++)
             {
                 char* imp_module_name = (char*)((DWORD)dos_header + (DWORD)(import_desc->Name));
 
                 if (_stricmp(imp_module_name, hooks[i].module_name) == 0)
                 {
-                    HMODULE cur_mod = GetModuleHandle(hooks[i].module_name);
+                    HMODULE cur_mod = GetModuleHandleA(hooks[i].module_name);
 
                     PIMAGE_THUNK_DATA first_thunk =
                         (PIMAGE_THUNK_DATA)((DWORD)dos_header + (DWORD)import_desc->FirstThunk);
 
-                    PIMAGE_THUNK_DATA original_first_thunk =
-                        (PIMAGE_THUNK_DATA)((DWORD)dos_header + (DWORD)import_desc->OriginalFirstThunk);
-
                     while (first_thunk->u1.Function)
                     {
                         for (int x = 0; hooks[i].data[x].function_name[0]; x++)
@@ -260,7 +263,6 @@ void hook_patch_obfuscated_iat_list(HMODULE hmod, BOOL unhook, HOOKLIST* hooks,
                         }
 
                         first_thunk++;
-                        original_first_thunk++;
                     }
                 }
             }
@@ -298,6 +300,12 @@ void hook_patch_iat_list(HMODULE hmod, BOOL unhook, HOOKLIST* hooks, BOOL is_loc
 
         while (import_desc->FirstThunk)
         {
+            if (!import_desc->OriginalFirstThunk || !import_desc->Name)
+            {
+                import_desc++;
+                continue;
+            }
+
             for (int i = 0; hooks[i].module_name[0]; i++)
             {
                 char* imp_module_name = (char*)((DWORD)dos_header + (DWORD)(import_desc->Name));
@@ -325,30 +333,8 @@ void hook_patch_iat_list(HMODULE hmod, BOOL unhook, HOOKLIST* hooks, BOOL is_loc
                                 if (!is_local && (hooks[i].data[x].flags & HOOK_LOCAL_ONLY))
                                     continue;
 
-                                /* avoid exceptions with obfuscated binaries in debug build */
-#if defined(_DEBUG) || defined(__GNUC__)
-                                MEMORY_BASIC_INFORMATION mbi = { 0 };
-                                if (VirtualQuery((void*)import->Name, &mbi, sizeof(mbi)))
-                                {
-                                    DWORD mask = (
-                                        PAGE_READONLY | 
-                                        PAGE_READWRITE | 
-                                        PAGE_WRITECOPY | 
-                                        PAGE_EXECUTE_READ | 
-                                        PAGE_EXECUTE_READWRITE | 
-                                        PAGE_EXECUTE_WRITECOPY);
-                                    
-                                    BOOL b = !(mbi.Protect & mask);
-
-                                    if (mbi.Protect & (PAGE_GUARD | PAGE_NOACCESS)) 
-                                        b = TRUE;
-
-                                    if (b)
-                                        continue;
-                                }
-                                else
+                                if (util_is_bad_read_ptr((void*)import->Name))
                                     continue;
-#endif
 
                                 if (_stricmp((const char*)import->Name, hooks[i].data[x].function_name) == 0)
                                 {
diff --git a/src/utils.c b/src/utils.c
index bddc06b..446d342 100644
--- a/src/utils.c
+++ b/src/utils.c
@@ -11,6 +11,31 @@
 #include "config.h"
 
 
+BOOL util_is_bad_read_ptr(void* p)
+{
+    MEMORY_BASIC_INFORMATION mbi = { 0 };
+    if (VirtualQuery(p, &mbi, sizeof(mbi)))
+    {
+        DWORD mask = (
+            PAGE_READONLY |
+            PAGE_READWRITE |
+            PAGE_WRITECOPY |
+            PAGE_EXECUTE_READ |
+            PAGE_EXECUTE_READWRITE |
+            PAGE_EXECUTE_WRITECOPY);
+
+        BOOL b = !(mbi.Protect & mask);
+
+        if (mbi.Protect & (PAGE_GUARD | PAGE_NOACCESS))
+            b = TRUE;
+
+        if (!b)
+            return b;
+    }
+
+    return TRUE;
+}
+
 BOOL util_is_minimized(HWND hwnd)
 {
     RECT rc = { 0 };