Unity Studio | @sskaje

By @sskaje
Link: https://sskaje.me/2018/02/unity3d-asset-bundle-decrypt/

这里只说 AssetBundle，只有思路。

1 废话般前提：逻辑上 AssetBundle 文件加密后肯定是需要解密了，再进行加载。

2 Unity 加载AssetBundle文件可以使用 AssetBundle.LoadFromFile，加载内存流可以用AssetBundle.LoadFromMemory 和 AssetBundle.LoadFromStream。
这些方法对应还有代Async后缀的异步加载方法。
文档在：https://docs.unity3d.com/ScriptReference/AssetBundle.html

3 打断点，看backtrace。

4 慢慢调试。

在我这个场景里，il2cpp dump是没有需求的。

贴一个bt

* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1
  * frame #0: 0x0000000101234a68 global`AssetBundle_LoadFromMemory_m412557059
    frame #1: 0x000000010025a610 global`U3CLoadDynamicAssetBundleU3Ec__AnonStorey3_U3CU3Em__0_m1954562509 + 72
    frame #2: 0x000000010013a09c global`MainThreadDispatcher_SendAndWait_m4140732116 + 192
    frame #3: 0x0000000100259414 global`AssetBundleLoader_LoadDynamicAssetBundle_m153660618 + 540
    frame #4: 0x0000000100259e70 global`AssetBundleLoader_Load_m859069093 + 732
    frame #5: 0x000000010072930c global`SpriteLoader_Load_m3286678683 + 1784
    frame #6: 0x00000001005327c0 global`ExtImage_Awake_m3150663317 + 456
    frame #7: 0x00000001017d6ad0 global`RuntimeInvoker_Void_t1841601450(MethodInfo const*, void*, void**) + 28
    frame #8: 0x00000001021a1e24 global`il2cpp::vm::Runtime::Invoke(MethodInfo const*, void*, void**, Il2CppException**) + 68
    frame #9: 0x0000000101c035f4 global`ScriptingInvocation::Invoke(Il2CppException**, bool) + 60
    frame #10: 0x0000000101c0352c global`ScriptingInvocation::InvokeChecked(Il2CppException**) + 68
    frame #11: 0x0000000101ce10ac global`MonoBehaviour::CallMethodInactive(ScriptingMethodIl2Cpp) + 88
    frame #12: 0x0000000101ce2e34 global`MonoBehaviour::CallAwake() + 76
    frame #13: 0x0000000101ce3134 global`MonoBehaviour::AddToManager() + 132
    frame #14: 0x0000000101ce2dcc global`MonoBehaviour::AwakeFromLoad(AwakeFromLoadMode) + 568
    frame #15: 0x0000000101c0c548 global`AwakeFromLoadQueue::InvokePersistentManagerAwake(AwakeFromLoadQueue::Item*, unsigned int, AwakeFromLoadMode) + 96
    frame #16: 0x0000000101c0c48c global`AwakeFromLoadQueue::PersistentManagerAwakeFromLoad(int, AwakeFromLoadMode) + 140
    frame #17: 0x0000000101c0c3e8 global`AwakeFromLoadQueue::PersistentManagerAwakeFromLoad() + 36
    frame #18: 0x0000000101bfc9b8 global`LoadSceneOperation::CompleteAwakeSequence() + 96
    frame #19: 0x0000000101bfc3e0 global`LoadSceneOperation::PostLoadSceneAdditive() + 32
    frame #20: 0x0000000101bfc304 global`LoadSceneOperation::IntegrateMainThread() + 80
    frame #21: 0x0000000101bfd01c global`PreloadManager::UpdatePreloadingSingleStep(PreloadManager::UpdatePreloadingFlags, int) + 316
    frame #22: 0x0000000101bfd59c global`PreloadManager::UpdatePreloading() + 252
    frame #23: 0x0000000101b07c4c global`PlayerLoop() + 332
    frame #24: 0x0000000101d4381c global`UnityPlayerLoopImpl(bool) + 32
    frame #25: 0x0000000100047c80 global`UnityRepaint + 140
    frame #26: 0x0000000100047b6c global`-[UnityAppController(Rendering) repaintDisplayLink] + 88
    frame #27: 0x0000000184da2f24 QuartzCore`CA::Display::DisplayLinkItem::dispatch(unsigned long long) + 44
    frame #28: 0x0000000184da2dd0 QuartzCore`CA::Display::DisplayLink::dispatch_items(unsigned long long, unsigned long long, unsigned long long) + 444
    frame #29: 0x0000000181dba094 IOKit`IODispatchCalloutFromCFMessage + 372
    frame #30: 0x0000000181ae2e50 CoreFoundation`__CFMachPortPerform + 180
    frame #31: 0x0000000181afb218 CoreFoundation`__CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 56
    frame #32: 0x0000000181afa9cc CoreFoundation`__CFRunLoopDoSource1 + 436
    frame #33: 0x0000000181af84b0 CoreFoundation`__CFRunLoopRun + 1840
    frame #34: 0x0000000181a262b8 CoreFoundation`CFRunLoopRunSpecific + 444
    frame #35: 0x00000001834da198 GraphicsServices`GSEventRunModal + 180
    frame #36: 0x0000000187a6d7fc UIKit`-[UIApplication _run] + 684
    frame #37: 0x0000000187a68534 UIKit`UIApplicationMain + 208
    frame #38: 0x00000001000417dc global`main + 156
    frame #39: 0x0000000180a095b8 libdyld.dylib`start + 4

* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 1.1

* frame #0: 0x0000000101234a68 global`AssetBundle_LoadFromMemory_m412557059

frame #1: 0x000000010025a610 global`U3CLoadDynamicAssetBundleU3Ec__AnonStorey3_U3CU3Em__0_m1954562509 + 72

frame #2: 0x000000010013a09c global`MainThreadDispatcher_SendAndWait_m4140732116 + 192

frame #3: 0x0000000100259414 global`AssetBundleLoader_LoadDynamicAssetBundle_m153660618 + 540

frame #4: 0x0000000100259e70 global`AssetBundleLoader_Load_m859069093 + 732

frame #5: 0x000000010072930c global`SpriteLoader_Load_m3286678683 + 1784

frame #6: 0x00000001005327c0 global`ExtImage_Awake_m3150663317 + 456

frame #7: 0x00000001017d6ad0 global`RuntimeInvoker_Void_t1841601450(MethodInfo const*, void*, void**) + 28

frame #8: 0x00000001021a1e24 global`il2cpp::vm::Runtime::Invoke(MethodInfo const*, void*, void**, Il2CppException**) + 68

frame #9: 0x0000000101c035f4 global`ScriptingInvocation::Invoke(Il2CppException**, bool) + 60

frame #10: 0x0000000101c0352c global`ScriptingInvocation::InvokeChecked(Il2CppException**) + 68

frame #11: 0x0000000101ce10ac global`MonoBehaviour::CallMethodInactive(ScriptingMethodIl2Cpp) + 88

frame #12: 0x0000000101ce2e34 global`MonoBehaviour::CallAwake() + 76

frame #13: 0x0000000101ce3134 global`MonoBehaviour::AddToManager() + 132

frame #14: 0x0000000101ce2dcc global`MonoBehaviour::AwakeFromLoad(AwakeFromLoadMode) + 568

frame #15: 0x0000000101c0c548 global`AwakeFromLoadQueue::InvokePersistentManagerAwake(AwakeFromLoadQueue::Item*, unsigned int, AwakeFromLoadMode) + 96

frame #16: 0x0000000101c0c48c global`AwakeFromLoadQueue::PersistentManagerAwakeFromLoad(int, AwakeFromLoadMode) + 140

frame #17: 0x0000000101c0c3e8 global`AwakeFromLoadQueue::PersistentManagerAwakeFromLoad() + 36

frame #18: 0x0000000101bfc9b8 global`LoadSceneOperation::CompleteAwakeSequence() + 96

frame #19: 0x0000000101bfc3e0 global`LoadSceneOperation::PostLoadSceneAdditive() + 32

frame #20: 0x0000000101bfc304 global`LoadSceneOperation::IntegrateMainThread() + 80

frame #21: 0x0000000101bfd01c global`PreloadManager::UpdatePreloadingSingleStep(PreloadManager::UpdatePreloadingFlags, int) + 316

frame #22: 0x0000000101bfd59c global`PreloadManager::UpdatePreloading() + 252

frame #23: 0x0000000101b07c4c global`PlayerLoop() + 332

frame #24: 0x0000000101d4381c global`UnityPlayerLoopImpl(bool) + 32

frame #25: 0x0000000100047c80 global`UnityRepaint + 140

frame #26: 0x0000000100047b6c global`-[UnityAppController(Rendering) repaintDisplayLink] + 88

frame #27: 0x0000000184da2f24 QuartzCore`CA::Display::DisplayLinkItem::dispatch(unsigned long long) + 44

frame #28: 0x0000000184da2dd0 QuartzCore`CA::Display::DisplayLink::dispatch_items(unsigned long long, unsigned long long, unsigned long long) + 444

frame #29: 0x0000000181dba094 IOKit`IODispatchCalloutFromCFMessage + 372

frame #30: 0x0000000181ae2e50 CoreFoundation`__CFMachPortPerform + 180

frame #31: 0x0000000181afb218 CoreFoundation`__CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 56

frame #32: 0x0000000181afa9cc CoreFoundation`__CFRunLoopDoSource1 + 436

frame #33: 0x0000000181af84b0 CoreFoundation`__CFRunLoopRun + 1840

frame #34: 0x0000000181a262b8 CoreFoundation`CFRunLoopRunSpecific + 444

frame #35: 0x00000001834da198 GraphicsServices`GSEventRunModal + 180

frame #36: 0x0000000187a6d7fc UIKit`-[UIApplication _run] + 684

frame #37: 0x0000000187a68534 UIKit`UIApplicationMain + 208

frame #38: 0x00000001000417dc global`main + 156

frame #39: 0x0000000180a095b8 libdyld.dylib`start + 4

工具：
https://github.com/Perfare/UnityStudio
https://github.com/HearthSim/UnityPack

Unity3d资源文件解密 by @sskaje: https://sskaje.me/2018/02/unity3d-asset-bundle-decrypt/