We recently had a pen tester audit our app and one of the findings was that a person with a jailbroken device can attach a local debugger.
The solution they suggested was to enable PT_DENY_ATTACH when starting up the app. This is fairly easy to do in a native app but I haven't been able to figure it out with our Xamarin app (not forms).
I've tried creating an objc framework in Xcode, binding that and pulling it in. I've also tried to create a shared c++ library but that isn't possible in VS Mac.
I know that PT_DENY_ATTACH has been circumvented but I'd still like to know how to implement it.
Thanks!
It turns out that my objc framework was behaving properly just not in the way I expected. For some reason I was still able to attach the Visual Studio debugger but when I move to Xcode and try to attach its debugger it fails when the framework is called.
To answer my question:
In Xcode I created a new static library with one class:
GDBManager.h
#import <Foundation/Foundation.h>
#interface GDBManager : NSObject
+(void)DisableGDB;
#end
GDBManager.m
#import "GDBManager.h"
#import <dlfcn.h>
#import <sys/types.h>
#implementation GDBManager
typedef int (*ptrace_ptr_t)(int _request, pid_t _pid, caddr_t _addr, int _data);
#define PT_DENY_ATTACH 31
+(void)DisableGDB {
void* handle = dlopen(0, RTLD_GLOBAL | RTLD_NOW);
ptrace_ptr_t ptrace_ptr = dlsym(handle, "ptrace");
ptrace_ptr(PT_DENY_ATTACH, 0, 0, 0);
dlclose(handle);
}
#end
I followed these instructions to create a fat file for my library and to use that in a binding project.
https://learn.microsoft.com/en-us/xamarin/ios/platform/binding-objective-c/walkthrough
I then add the generated dll to my Xamarin.iOS project and call it above UIApplication.Main(args, null, "AppDelegate"); in Main.cs
Related
I am creating Swift framework in which I have to use Objective-C class. So I went through this link. This is the public header of my framework :
#import <UIKit/UIKit.h>
//! Project version number for Test.
FOUNDATION_EXPORT double TestVersionNumber;
//! Project version string for Test.
FOUNDATION_EXPORT const unsigned char TestVersionString[];
// In this header, you should import all the public headers of your framework using statements like #import <Test/PublicHeader.h>
#import <arpa/inet.h>
#import <ifaddrs.h>
#import <netdb.h>
#import <sys/socket.h>
#import <MyTest/MPAppDelegateProxy.h>
Now in class MPAppDelegateProxy, I have to use a Swift class which I have created. This is :
#import "MPAppDelegateProxy.h"
#import "MyTest.h"
#implementation MPAppDelegateProxy
+ (void)proxyAppDelegate {
[MPGlobal MPLog:#"App delegate not set, unable to perform automatic setup." file:#"MPAppDelegateProxy.m" function:#"proxyAppDelegate" line:32];
// rest of code
}
MPGlobal is one of my Swift class. But I am getting :
Use of undeclared identifier 'MPGlobal'
Note : I have added #objC before MPGlobal.
You need to import <Target>-Swift.h file.
This is known as Objective-C Generated Interface Header Name.
You can find it in your Target's build settings.
This file is auto generated by compiler and it needs to be imported in Objective-C files.
change the SWIFT_OBJC_INTERFACE_HEADER_NAME build setting and making it the same across different targets. To do so change the instruction that generates this property from $(SWIFT_MODULE_NAME)-Swift.h to $(PROJECT_NAME)-Swift.h as explained here
After doing this Clean Build Folder by pressing Alt and going into Product menu. Since name of header is shared among targets now it can be imported once in the .m ObjectiveC file and all targets can benefit from Swift classes.
If after building it still shows the error, ensure that the header can be reached from XCode by Cmd clicking on its name. It should open a file that contains code similar to this:
SWIFT_CLASS("_TtC27ProjectName_Summary11MyClass")
#interface MyClass : NSObject
- (nonnull instancetype)init OBJC_DESIGNATED_INITIALIZER;
#end
If need to ensure that those headers are being generated open a terminal and use this command
find ~/Library/Developer/Xcode/DerivedData -name "*Swift.h"
You should see one header for each target
Another issue that happened to me after those changes is that it started giving errors on ObjectiveC code that I didn't touch. The problem was due to the position of the import, as reported here:
Exactly where at the top of a .m file you #import the hidden bridging
header can make a difference. The usual sign of trouble is that you
get an “Unknown type name” compile error, where the unknown type is a
class declared in Objective-C. The solution is to #import the .h file
containing the declaration for the unknown type in your Objective-C
files as well, before you #import the hidden bridging header. Having
to do this can be an annoyance, especially if the Objective-C file in
question has no need to know about this class, but it resolves the
issue and allows compilation to proceed.
At the very end the code compiles and runs on device and simulator!
Original answer
Also you can try this,
You needed to import the -Swift.h for for both the framework and the app target
For Example :
#import <UIKit/UIKit.h>
#import <AVFoundation/AVFoundation.h>
#import <Foundation/Foundation.h>
#import "XLPagerTabStrip-Swift.h"
#import "RealmSwift-Swift.h"
...... // Add all frameworks, subclasses, and dependance ios frameworks
#import "MyProject-Swift.h"
You can read this article How to import file header and check paths
I tried calling UnitySendMessage method in my iOS Framework project using swift language but it is showing this error-
Use of unresolved identifier 'UnitySendMessage'
Here is the code snippet for my swift file-
import Foundation
#objc public class Example : NSObject{
#objc open static let shared = Example()
#objc open func printMsg(){
print("\(#function) is called with message:");
UnitySendMessage("CallbackTarget", "OnCallFromSwift", "Hello, Unity!");
}
}
Getting stuck here, can you please tell me what am I missing?
check Answer here.
UnitySendMessage is in libiPhone-lib.a, and as far as I can tell, the
Unity folks don't include any header that declares it.
I just added the following to my code
extern void UnitySendMessage(const char *, const char *, const char
*);
If you look at the generated AppController.mm, they basically do the
same thing for the various UnitySendXXX functions, rather than
including a header.
Having said that, while you will be able to build a library that calls
UnitySendMessage, that library probably won't work unless it's linked
into a Unity project, since UnitySendMessage is going to require more
than just libiPhone-lib.a to actually work.
Just add this code to your Bridging-Header.h file:
#import "UnityInterface.h"
Make sure that your files are in the XCode project that was build from Unity, so the actual UnityInterface file that is created by unity is present.
Worked for me :)
I am using the OpenCV iOS Framework in a project. I followed the necessary steps to include the framework into the project.
The Project is written using Swift 3.
One of my classes that contains the core functionality of the App is written in Objective-C++. I included the header of the class in my Bridge-header file but when trying to run the project I get the following error:
error core.hpp header must be compiled as C++
After researching online and on SO, the most common solution presented was to create a Wrapper class that would be imported in the bridge header. However, after following this article I face the same problem.
The Header file of my class looks like this:
#if TARGET_OS_IPHONE
#import <UIKit/UIKit.h>
#define IMAGE_CLASS UIImage
#elif TARGET_OS_MAC
#import <Cocoa/Cocoa.h>
#define IMAGE_CLASS NSImage
#endif
#import <AGGeometryKit/AGKQuad.h>
#import <stdio.h>
#import <opencv2/opencv.hpp>
#import <Foundation/Foundation.h>
typedef void (^DebugBlock)(cv::Mat current_image, std::string current_image_name);
#interface ImageScanner : NSObject
/**
* Singleton for access to the scanner.
*
* #return Shared scanner.
*/
+ (instancetype)sharedScanner;
Does anyone have an idea what I might be missing?
Thank you in advance!
G.
had the same problem.. solved by importing any file that use openCV in the wrapperClass.mm file ...
SO Answer here
I am tinkering with the sample project "SpatialAudio" from Google VR SDK for Unity, to implement it in iOS.
I built it in Unity using the latest GVR SDK, so I had to replace a few deprecated keywords (GvrAudioSource instead of CardboardAudioSource, etc.)
If I build it in Xcode just as Unity gives it to me, it runs fine in the physical device.
Then, I tried to edit the Unity-generated file 'main.mm' to change the default App Controller (UnityAppController) to a new one, let's call it NewAppController.
// main.mm
...
const char* AppControllerClassName = "UnityAppController";
...
//UIApplicationMain(argc, argv, nil, [NSString stringWithUTF8String:AppControllerClassName]); // old
UIApplicationMain(argc, argv, nil, [NSString stringWithUTF8String:"NewAppController"]); // new
NewAppController is a class which inherits from UnityAppController and does not override any of its methods or properties, like this:
#interface NewAppController : UnityAppController
#end
#implementation NewAppController
#end
I thought that it should work exactly the same as before, but now I get the following warning in runtime:
"Audio effect GVR Audio Renderer could not be found. Check that the project contains the correct native audio plugin libraries and that the importer settings are set up correctly."
Everything else works just fine: I can see the video and even hear the sounds, but only they are not 'spatialized'.
I am using:
GVR SDK 1.1,
Unity 5.5.0f3,
iOS 10.1.1
I found the solution. I was missing two important things: First, messing with main.mm causes a lot of trouble. The correct approach for defining a custom App Controller is to create a subclass of UnityAppController and adding the macro IMPL_APP_CONTROLLER_SUBCLASS(name_of_the_class) at the bottom of its .mm file. Second, Unity automatically generates a custom app controller, called CardboardAppController, which is located in the build directory, under 'Libraries/Plugins/iOS'. One of its functions is registering the unity audio effect plugin. I was bypassing this file without knowing, causing the audio renderer to not initialize properly. So my solution was to comment out the macro at the end of the file CardboardAppController.mm (line 71):
//IMPL_APP_CONTROLLER_SUBCLASS(CardboardAppController)
And defining the new custom controller as a subclass of CardboardAppController:
#import "CardboardAppController.h"
#interface NewAppController : CardboardAppController
#end
#implementation NewAppController
#end
IMPL_APP_CONTROLLER_SUBCLASS(NewAppController)
I recently came around this article (http://www.splinter.com.au/2014/09/16/storing-secret-keys/) that talks about obfuscation on iOS.
I quote:
To somewhat mitigate the risk of crackers attacking your app with a debugger (LLDB or GDB), you can insert some code in your app that makes it crash as soon as it detects a debugger attached. The iTunes app uses this technique, you can read about it here.
This is achieved by calling the following code in main()
#import <dlfcn.h>
#import <sys/types.h>
typedef int (*ptrace_ptr_t)(int _request, pid_t _pid, caddr_t _addr, int _data);
#if !defined(PT_DENY_ATTACH)
#define PT_DENY_ATTACH 31
#endif // !defined(PT_DENY_ATTACH)
void disable_gdb() {
void* handle = dlopen(0, RTLD_GLOBAL | RTLD_NOW);
ptrace_ptr_t ptrace_ptr = dlsym(handle, "ptrace");
ptrace_ptr(PT_DENY_ATTACH, 0, 0, 0);
dlclose(handle);
}
I understand that these lines of code make the debugger crash when attached to the process but how does it achieve this behaviour?
Also, would that be impairing the stability of the app in any way?
Seems like a similar question on OS X has already been answered here: Implementing the PT_DENY_ATTACH anti-piracy code.
TL;DR - As Jim Ingham points out in the comments, it's a waste of time.