Merge pull request #18 from bR34Kr/master

Symbol hooking
joeyjurjens · Jul 10, 2020 · e161b23 · e161b23
2 parents 14beee1 + 4426300
commit e161b23
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Showing 3 changed files with 18 additions and 2 deletions.
diff --git a/template/Macros.h b/template/Macros.h
@@ -11,6 +11,7 @@
 
 #include <substrate.h>
 #include <mach-o/dyld.h>
+#include <dlfcn.h>
 
 // definition at Menu.h
 extern Menu *menu;
@@ -21,6 +22,11 @@ extern Switches *switches;
 #define HOOK(offset, ptr, orig) MSHookFunction((void *)getRealOffset(offset), (void *)ptr, (void **)&orig)
 #define HOOK_NO_ORIG(offset, ptr) MSHookFunction((void *)getRealOffset(offset), (void *)ptr, NULL)
 
+// Note to not prepend an underscore to the symbol. See Notes on the Apple manpage (https://developer.apple.com/library/archive/documentation/System/Conceptual/ManPages_iPhoneOS/man3/dlsym.3.html)
+#define HOOKSYM(sym, ptr, org) MSHookFunction((void*)dlsym((void *)-2, sym), (void *)ptr, (void **)&org)
+#define HOOKSYM_NO_ORIG(sym, ptr)  MSHookFunction((void*)dlsym((void *)-2, sym), (void *)ptr, NULL)
+#define getSym(symName) dlsym((void *)-2, symName)
+
 // Convert hex color to UIColor, usage: For the color #BD0000 you'd use: UIColorFromHex(0xBD0000)
 #define UIColorFromHex(hexColor) [UIColor colorWithRed:((float)((hexColor & 0xFF0000) >> 16))/255.0 green:((float)((hexColor & 0xFF00) >> 8))/255.0 blue:((float)(hexColor & 0xFF))/255.0 alpha:1.0]
 

diff --git a/template/sample.xm b/template/sample.xm
@@ -69,6 +69,13 @@ int get_Gems(void *this_) {
   return old_get_Gems(this_);
 }
 
+void (*old_gl_draw_elements)(GLenum mode, GLsizei count, GLenum type, const void *indices);
+
+void gl_draw_elements(GLenum mode, GLsizei count, GLenum type, const void *indices) {
+  // This hook is absolutely useless. Just to show a PoC
+  old_gl_draw_elements(mode, count type, indices);
+}
+
 void setup() {
 
   //public virtual void UpdateCharacter(float deltaTime); // RVA: 0x10194DE30 Offset: 0x194DE30 -> CharacterBase
@@ -79,6 +86,9 @@ void setup() {
 
   //public int get_Gems(); // RVA: 0x1018A3F24 Offset: 0x18A3F24
   HOOK(0x1018A3F24, get_Gems, old_get_Gems);
+
+  // This entry is fictional but is just there to show a PoC.
+  HOOKSYM("glDrawElements", gl_draw_elements, old_gl_draw_elements);
 
     [switches addTextfieldSwitch:@"Custom Coins:"
                 description:@"Here you can enter your own coins amount!"
@@ -173,4 +183,4 @@ static void didFinishLaunching(CFNotificationCenterRef center, void *observer, C
 
 %ctor {
   CFNotificationCenterAddObserver(CFNotificationCenterGetLocalCenter(), NULL, &didFinishLaunching, (CFStringRef)UIApplicationDidFinishLaunchingNotification, NULL, CFNotificationSuspensionBehaviorDeliverImmediately);
-}
+}
diff --git a/template/versionCheck.sh b/template/versionCheck.sh
@@ -1,5 +1,5 @@
 #!/bin/bash
-VERSION='0.6.6'
+VERSION='0.6.7'
 # Don't remove the above line. Serves as the version this script will fetch. Only update when a new version is out.
 
 ERROR='\033[1;31m[*] Error:\033[1;37m '