移动基板可以钩住这个吗?

Can mobilesubstrate hook this?

本文关键字：移动      更新时间：2023-10-16

我想挂接一个名为png_handle_IHDR的函数，该函数在 ImageIO 框架中本地声明。我使用MobileSafari作为过滤器。但是在调用原始函数时，移动野生动物园崩溃了。在检查NSLog时，我得到这个：

Jun  5 17:21:08 unknown MobileSafari[553] <Warning>: dlopen ImageIO success!
Jun  5 17:21:08 unknown MobileSafari[553] <Warning>: Zeroing of nlist success!
Jun  5 17:21:08 unknown MobileSafari[553] <Warning>: method name successfully assigned!
Jun  5 17:21:08 unknown MobileSafari[553] <Warning>: nlist SUCCESS! nlsetting..
Jun  5 17:21:08 unknown MobileSafari[553] <Warning>: nlset success! Hooking..
Jun  5 17:21:09 unknown MobileSafari[553] <Warning>: Png IHDR handle hooking!
Jun  5 17:21:09 unknown UIKitApplication:com.apple.mobilesafari[0x819][553] <Notice>: libpng error: Invalid IHDR chunk
Jun  5 17:21:09 unknown ReportCrash[554] <Notice>: Formulating crash report for process MobileSafari[553]
Jun  5 17:21:09 unknown com.apple.launchd[1] <Warning>: (UIKitApplication:com.apple.mobilesafari[0x819]) Job appears to have crashed: Abort trap: 6
Jun  5 17:21:09 unknown SpringBoard[530] <Warning>: Application 'Safari' exited abnormally with signal 6: Abort trap: 6
我

立即发现，我很可能弄错了png_handle_IHDR的功能原型。以下是我在调整中的代码：

#import <CoreFoundation/CoreFoundation.h>
#include <substrate.h>
#define ImageIO "/System/Library/Frameworks/ImageIO.framework/ImageIO"
void (*png_handle_IHDR)();
MSHook(void, png_handle_IHDR){
    NSLog(@"Png IHDR handle hooking!n");
    _png_handle_IHDR(); //crashed here!!
    NSLog(@"Png IHDR handle hooking finished!n");
}
template <typename Type_>
static void nlset(Type_ &function, struct nlist *nl, size_t index) {
    struct nlist &name(nl[index]);
    uintptr_t value(name.n_value);
    if ((name.n_desc & N_ARM_THUMB_DEF) != 0)
        value |= 0x00000001;
    function = reinterpret_cast<Type_>(value);
}
MSInitialize {
        if (dlopen(ImageIO, RTLD_LAZY | RTLD_NOLOAD)!=NULL)
        {       
                NSLog(@"dlopen ImageIO success!n");
                struct nlist nl[2];
                bzero(&nl, sizeof(nl));
                NSLog(@"Zeroing of nlist success!n");
                nl[0].n_un.n_name = (char*) "_png_handle_IHDR"; 
                NSLog(@"method name successfully assigned!n");
                nlist(ImageIO,nl);
                NSLog(@"nlist SUCCESS! nlsetting..n");
                nlset(png_handle_IHDR, nl, 0);  
                NSLog(@"nlset success! Hooking..n");
                MSHookFunction(png_handle_IHDR,MSHake(png_handle_IHDR));
        }        
}

我的制作文件是这样的：

include theos/makefiles/common.mk
TWEAK_NAME = privateFunctionTest
privateFunctionTest_FILES = Tweak.xm
include $(THEOS_MAKE_PATH)/tweak.mk
privateFunctionTest_FRAMEWORKS = UIKit ImageIO CoreGraphics Foundation CoreFoundation

编辑：问题是，知道原始函数参数对于成功的钩子是必要的吗？如果是，从反汇编中获取功能原型是唯一的方法吗？在任何 SDK 标头中都没有对此进行定义。谢谢。

好的，我反编译了函数，并让反编译器猜到了函数原型。只要参数和返回类型广泛匹配，例如 bool : int，unsigned int : int，它仍然有效，而不会杀死处决。所以这有效：

int *png_handle_IHDR(int a1, int a2, int a3);
MSHook(int, png_handle_IHDR, int a1, int a2, int a3){
    NSLog(@"png_handle_IHDR(%d,%d,%d)", a1,a2,a3);
    int val = _png_handle_IHDR(a1,a2,a3);
    NSLog(@"Png IHDR handle hooking finished, returning %d as result!", val);
    return val;
}
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