Resolvendo problemas com disassembly no IOS.

Resolvendo problemas com disassembly no IOS.

Transcript

1. Cocoa Heads Rafael Bertholdo 28/03/2017 Resolvendo problemas com disassembly no IOS.
2. • Engenheiro de software @ Ci&T • Guitarra • Aion e Dota nas horas vagas • Delphi, C++, Assembly, PHP, Java, C#.net, Ruby, Objective C • github.com/rafabertholdo • rafabertholdo@gmail.com Rafael Bertholdo
3. Agenda • Porque • Como • Onde • Exemplo • Extra: Method Swilling
4. “Programar é mover zeros e uns de um lugar pro outro”. @electricadventures
5. Nem sempre a documentação é suficiente, ou quem fez a biblioteca ou executável não quer que você saiba o que a caixa preta faz. Porque
6. • Linguagens que geram código intermediário ◦ .net -> dotPeek (free) ◦ Java -> jD (free) • Linguagens que geram código específico do hardware ◦ OSX ▪ Hopper disassembly (R$326,01) ◦ Windows ▪ PE Explorer ▪ X64dbg ▪ olyDbg ◦ Unix ▪ otool ◦ Cross-platform ▪ IDA + Hex-ray (U$589 ~ U$2350) Como
7. In C# class instances are created like this: Car myCar = new Car(1, 4); Car yourCar = new Car(1, 3); And these statements are roughly the same as these instructions: ldc.i4.1 ldc.i4.4 newobj instance void Car::.ctor(int, int) stloc.0 // myCar = new Car(1, 4); ldc.i4.1 ldc.i4.3 newobj instance void Car::.ctor(int, int) stloc.1 // yourCar = new Car(1, 3); Microsoft Intermediate Language (MSIL)
8. JetBrains dotPeek
9. Código específico do hardware
10. Hopper
11. Hopper (cont)
12. Código específico do hardware
13. Onde
14. Com UITextField em modo senha, ao perder o foco e voltar, o componente limpa o campo todo. Exemplo
15. Hopper disassembly
16. UIFieldEditor header
17. Solução
18. Assembly Language - Succinctly - Chris Rose (free) https://www.syncfusion.com/resources/techportal/eboo ks/assemblylanguage Indicação de leitura
19. “Method swizzling is the process of changing the implementation of an existing selector.” Matt Thompson Extra: Method Swizzling
20. #import <objc/runtime.h> @implementation UIViewController (Tracking) + (void)load { static dispatch_once_t onceToken; dispatch_once(&onceToken, ^{ //Swizzling happens here }); } - (void)xxx_viewWillAppear:(BOOL)animated { [self xxx_viewWillAppear:animated]; NSLog(@"viewWillAppear: %@", self); } @end
21. Class class = [self class]; SEL originalSelector = @selector(viewWillAppear:); SEL swizzledSelector = @selector(xxx_viewWillAppear:); Method originalMethod = class_getInstanceMethod(class, originalSelector); Method swizzledMethod = class_getInstanceMethod(class, swizzledSelector); BOOL didAddMethod = class_addMethod(class, originalSelector, method_getImplementation(swizzledMethod), method_getTypeEncoding(swizzledMethod)); if (didAddMethod) { class_replaceMethod(class, swizzledSelector, method_getImplementation(originalMethod), method_getTypeEncoding(originalMethod)); } else { method_exchangeImplementations(originalMethod, swizzledMethod); }
22. THANK YOU FOR YOUR TIME!