An example of how to inject code to call dlopen and load a dylib into a remote mach task. Tested on 12.5 M1 Pro.

inject.c

#include <dlfcn.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <mach/mach.h>
#include <mach/error.h>
#include <errno.h>
#include <stdlib.h>
#include <sys/sysctl.h>
#include <sys/mman.h>

#include <sys/stat.h>
#include <pthread.h>
#ifdef __arm64__
//#include "mach/arm/thread_status.h"

// Apple says: mach/mach_vm.h:1:2: error: mach_vm.h unsupported
// And I say, bullshit.
kern_return_t mach_vm_allocate
(
        vm_map_t target,
        mach_vm_address_t *address,
        mach_vm_size_t size,
        int flags
);

kern_return_t mach_vm_write
(
        vm_map_t target_task,
        mach_vm_address_t address,
        vm_offset_t data,
        mach_msg_type_number_t dataCnt
);




#else
#include <mach/mach_vm.h>
#endif

#define STACK_SIZE 65536
#define CODE_SIZE 128

//
// Based on http://newosxbook.com/src.jl?tree=listings&file=inject.c
// Updated to work on Mojave by creating a stub mach thread that then
// creates a real pthread. Injected mach thread is terminated to clean
// up as well.
//
// Due to popular request:
//
// Simple injector example (and basis of coreruption tool).
//
// If you've looked into research on injection techniques in OS X, you
// probably know about mach_inject. This tool, part of Dino Dai Zovi's
// excellent "Mac Hacker's Handbook" (a must read - kudos, DDZ) was
// created to inject code in PPC and i386. Since I couldn't find anything
// for x86_64 or ARM, I ended up writing my own tool.

// Since, this tool has exploded in functionality - with many other features,
// including scriptable debugging, fault injection, function hooking, code
// decryption,  and what not - which comes in *really* handy on iOS.
//
// coreruption is still closed source, due its highly.. uhm.. useful
// nature. But I'm making this sample free, and I have fully annotated this.
// The rest of the stuff you need is in Chapters 11 and 12 MOXiI 1, with more
// to come in the 2nd Ed (..in time for iOS 9 :-)
//
// Go forth and spread your code :-)
//
// J (info@newosxbook.com) 02/05/2014
//
// v2: With ARM64 -  06/02/2015 NOTE - ONLY FOR **ARM64**, NOT ARM32!
// Get the full bundle at - http://NewOSXBook.com/files/injarm64.tar
// with sample dylib and with script to compile this neatly.
//
//**********************************************************************
// Note ARM code IS messy, and I left the addresses wide apart. That's
// intentional. Basic ARM64 assembly will enable you to tidy this up and
// make the code more compact.
//
// This is *not* meant to be neat - I'm just preparing this for TG's
// upcoming OS X/iOS RE course (http://technologeeks.com/OSXRE) and thought
// this would be interesting to share. See you all in MOXiI 2nd Ed!
//**********************************************************************

// This sample code calls pthread_set_self to promote the injected thread
// to a pthread first - otherwise dlopen and many other calls (which rely
// on pthread_self()) will crash.
// It then calls dlopen() to load the library specified - which will trigger
// the library's constructor (q.e.d as far as code injection is concerned)
// and sleep for a long time. You can of course replace the sleep with
// another function, such as pthread_exit(), etc.
//
// (For the constructor, use:
//
// static void whicheverfunc() __attribute__((constructor));
//
// in the library you inject)
//
// Note that the functions are shown here as "_PTHRDSS", "DLOPEN__" and "SLEEP___".
// Reason being, that the above are merely placeholders which will be patched with
// the runtime addresses when code is actually injected.
char injectedCode[] =
#ifdef X86_64
    // "\xCC"                            // int3

    "\x55"                            // push       rbp
    "\x48\x89\xE5"                    // mov        rbp, rsp
    "\x48\x83\xEC\x10"                // sub        rsp, 0x10
    "\x48\x8D\x7D\xF8"                // lea        rdi, qword [rbp+var_8]
    "\x31\xC0"                        // xor        eax, eax
    "\x89\xC1"                        // mov        ecx, eax
    "\x48\x8D\x15\x21\x00\x00\x00"    // lea        rdx, qword ptr [rip + 0x21]
    "\x48\x89\xCE"                    // mov        rsi, rcx
    "\x48\xB8"                        // movabs     rax, pthread_create_from_mach_thread
    "PTHRDCRT"
    "\xFF\xD0"                        // call       rax
    "\x89\x45\xF4"                    // mov        dword [rbp+var_C], eax
    "\x48\x83\xC4\x10"                // add        rsp, 0x10
    "\x5D"                            // pop        rbp
    "\x48\xc7\xc0\x13\x0d\x00\x00"    // mov        rax, 0xD13
    "\xEB\xFE"                        // jmp        0x0
    "\xC3"                            // ret

    "\x55"                            // push       rbp
    "\x48\x89\xE5"                    // mov        rbp, rsp
    "\x48\x83\xEC\x10"                // sub        rsp, 0x10
    "\xBE\x01\x00\x00\x00"            // mov        esi, 0x1
    "\x48\x89\x7D\xF8"                // mov        qword [rbp+var_8], rdi
    "\x48\x8D\x3D\x1D\x00\x00\x00"    // lea        rdi, qword ptr [rip + 0x2c]
    "\x48\xB8"                        // movabs     rax, dlopen
    "DLOPEN__"
    "\xFF\xD0"                        // call       rax
    "\x31\xF6"                        // xor        esi, esi
    "\x89\xF7"                        // mov        edi, esi
    "\x48\x89\x45\xF0"                // mov        qword [rbp+var_10], rax
    "\x48\x89\xF8"                    // mov        rax, rdi
    "\x48\x83\xC4\x10"                // add        rsp, 0x10
    "\x5D"                            // pop        rbp
    "\xC3"                            // ret

    "LIBLIBLIBLIB"
    "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
    "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
    "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
    "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00";
#else
//"\x20\x8e\x38\xd4" //brk    #0xc471
"\xe0\x03\x00\x91\x00\x40\x00\xd1\xe1\x03\x1f\xaa\xe3\x03\x1f\xaa\xc4\x00\x00\x10\x62\x01\x00\x10\x85\x00\x40\xf9\xa0\x00\x3f\xd6\x07\x00\x00\x10\xe0\x00\x1f\xd6\x50\x54\x48\x52\x44\x43\x52\x54\x44\x4c\x4f\x50\x45\x4e\x5f\x5f\x50\x54\x48\x52\x44\x45\x58\x54\x21\x00\x80\xd2\xc0\x00\x00\x10\x47\xff\xff\x10\xe8\x00\x40\xf9\x00\x01\x3f\xd6\x67\xfe\xff\x10\xe0\x00\x1f\xd6\x4c\x49\x42\x4c\x49\x42\x4c\x49\x42\x4c\x49\x42\x4c\x49\x42\x4c\x49\x42\x4c\x49\x42\x4c\x49\x42\x4c\x49\x42\x4c\x49\x42\x4c\x49\x42\x4c\x49\x42\x4c\x49\x42\x4c\x49\x42\x4c\x49\x42\x4c\x49\x42\x4c\x49\x42\x4c\x49\x42\x4c\x49\x42\x4c\x49\x42\x4c\x49\x42\x4c\x49\x42\x4c\x49\x42\x4c\x49\x42\x4c\x49\x42\x4c\x49\x42\x4c\x49\x42\x4c\x49\x42";
/*
Compile: as shellcode.asm -o shellcode.o && ld ./shellcode.o -o shellcode -lSystem -syslibroot `xcrun -sdk macosx --show-sdk-path`

 .global _main
 .align 4

 _main:
         mov x0, sp
         sub x0, x0, #16


         mov x1, xzr
         mov x3, xzr
         adr x4, pthrdcrt

         adr x2, _thread

         ldr x5, [x4]
         blr x5


 _loop:
         adr x7, _loop
         br x7


 pthrdcrt: .ascii "PTHRDCRT"
 dlllopen: .ascii "DLOPEN__"
 pthrdext: .ascii "PTHRDEXT"

 _thread:
         mov x1, #1
         adr x0, lib
         adr x7, dlllopen
         ldr x8, [x7]
         blr x8
         adr x7, _loop
         br x7
	

 lib: .ascii "LIBLIBLIBLIBLIBLIBLIBLIBLIBLIBLIBLIBLIBLIBLIBLIBLIBLIBLIBLIBLIBLIBLIBLIBLIBLIBLIBLIB"
 */
#endif

int inject(pid_t pid, const char *lib)
{
    task_t remoteTask;
    struct stat buf;

    /**
     * First, check we have the library. Otherwise, we won't be able to inject..
     */
    int rc = stat(lib, &buf);
    if (rc != 0) {
        fprintf(stderr, "Unable to open library file %s (%s) - Cannot inject\n", lib, strerror(errno));
        //return (-9);
    }

    mach_error_t kr = 0;

    /**
    * Second - the critical part - we need task_for_pid in order to get the task port of the target
    * pid. This is our do-or-die: If we get the port, we can do *ANYTHING* we want. If we don't, we're
    * #$%#$%.
    *
    * In iOS, this will require the task_for_pid-allow entitlement. In OS X, this will require getting past
    * taskgated, but root access suffices for that.
    *
    */
    kr = task_for_pid(mach_task_self(), pid, &remoteTask);
    if (kr != KERN_SUCCESS) {
        fprintf(stderr, "Unable to call task_for_pid on pid %d: %s. Cannot continue!\n", pid, mach_error_string(kr));
        return (-1);
    }

    /**
     * From here on, it's pretty much straightforward -
     * Allocate stack and code. We don't really care *where* they get allocated. Just that they get allocated.
     * So, first, stack:
     */
    mach_vm_address_t remoteStack64 = (vm_address_t)NULL;
    mach_vm_address_t remoteCode64 = (vm_address_t)NULL;
    kr = mach_vm_allocate(remoteTask, &remoteStack64, STACK_SIZE, VM_FLAGS_ANYWHERE);
    if (kr != KERN_SUCCESS) {
        fprintf(stderr, "Unable to allocate memory for remote stack in thread: Error %s\n", mach_error_string(kr));
        return (-2);
    }
    else {
        fprintf(stderr, "Allocated remote stack @0x%llx\n", remoteStack64);
    }
    /**
     * Then we allocate the memory for the thread
     */
    remoteCode64 = (vm_address_t)NULL;
    kr = mach_vm_allocate(remoteTask, &remoteCode64, CODE_SIZE, VM_FLAGS_ANYWHERE);
    if (kr != KERN_SUCCESS) {
        fprintf(stderr, "Unable to allocate memory for remote code in thread: Error %s\n", mach_error_string(kr));
        return (-2);
    }

    /**
     * Patch code before injecting: That is, insert correct function addresses (and lib name) into placeholders
     *
     * Since we use the same shared library cache as our victim, meaning we can use memory addresses from
     * OUR address space when we inject..
     */

    int i = 0;
    char *possiblePatchLocation = (injectedCode);
    for (i = 0; i < 0x100; i++) {
        // Patching is crude, but works.
        //
        extern void *_pthread_set_self;
        possiblePatchLocation++;

        uint64_t addrOfPthreadCreate = (uint64_t)dlsym(RTLD_DEFAULT, "pthread_create_from_mach_thread");
        uint64_t addrOfPthreadExit = (uint64_t)dlsym(RTLD_DEFAULT, "pthread_exit");
        uint64_t addrOfDlopen = (uint64_t)dlopen;

        if (memcmp(possiblePatchLocation, "PTHRDCRT", 8) == 0) {
            printf("pthread_create_from_mach_thread @%llx\n", addrOfPthreadCreate);
            memcpy(possiblePatchLocation, &addrOfPthreadCreate, 8);
        }

        if (memcmp(possiblePatchLocation, "PTHRDEXT", 8) == 0) {
            printf("pthread_exit @%llx\n", addrOfPthreadExit);
            memcpy(possiblePatchLocation, &addrOfPthreadCreate, 8);
        }

        if (memcmp(possiblePatchLocation, "DLOPEN__", 6) == 0) {
            printf("dlopen @%llx\n", addrOfDlopen);
            memcpy(possiblePatchLocation, &addrOfDlopen, sizeof(uint64_t));
        }

        if (memcmp(possiblePatchLocation, "LIBLIBLIB", 9) == 0) {
            strcpy(possiblePatchLocation, lib);
        }
    }

    /**
        * Write the (now patched) code
      */
    kr = mach_vm_write(remoteTask,                 // Task port
                       remoteCode64,               // Virtual Address (Destination)
                       (vm_address_t)injectedCode, // Source
                       sizeof(injectedCode));                      // Length of the source

    if (kr != KERN_SUCCESS) {
        fprintf(stderr, "Unable to write remote thread memory: Error %s\n", mach_error_string(kr));
        return (-3);
    }

    /*
     * Mark code as executable - This also requires a workaround on iOS, btw.
     */
    kr = vm_protect(remoteTask, remoteCode64, sizeof(injectedCode), FALSE, VM_PROT_READ | VM_PROT_EXECUTE);

    /*
        * Mark stack as writable  - not really necessary
     */
    kr = vm_protect(remoteTask, remoteStack64, STACK_SIZE, TRUE, VM_PROT_READ | VM_PROT_WRITE);
    if (kr != KERN_SUCCESS) {
        fprintf(stderr, "Unable to set memory permissions for remote thread: Error %s\n", mach_error_string(kr));
        return (-4);
    }

    /*
     * Create thread - This is obviously hardware specific.
     */
#ifdef X86_64
        x86_thread_state64_t remoteThreadState64;
#else
    // Using unified thread state for backporting to ARMv7, if anyone's interested..
    struct arm_unified_thread_state remoteThreadState64;
#endif
        thread_act_t         remoteThread;

        memset(&remoteThreadState64, '\0', sizeof(remoteThreadState64) );

        remoteStack64 += (STACK_SIZE / 2); // this is the real stack
    //remoteStack64 -= 8;  // need alignment of 16

        const char* p = (const char*) remoteCode64;
#ifdef X86_64
        remoteThreadState64.__rip = (u_int64_t) (vm_address_t) remoteCode64;

        // set remote Stack Pointer
        remoteThreadState64.__rsp = (u_int64_t) remoteStack64;
        remoteThreadState64.__rbp = (u_int64_t) remoteStack64;
#else

    // Note the similarity - all we change are a couple of regs.
    remoteThreadState64.ash.flavor = ARM_THREAD_STATE64;
    remoteThreadState64.ash.count = ARM_THREAD_STATE64_COUNT;
    remoteThreadState64.ts_64.__pc = (u_int64_t) remoteCode64;
    remoteThreadState64.ts_64.__sp = (u_int64_t) remoteStack64;
// __uint64_t    __x[29];  /* General purpose registers x0-x28 */
#endif

    printf ("Remote Stack 64  0x%llx, Remote code is %p\n", remoteStack64, p );

    /*
     * create thread and launch it in one go
     */
#ifdef X86_64
kr = thread_create_running( remoteTask, x86_THREAD_STATE64,
(thread_state_t) &remoteThreadState64, x86_THREAD_STATE64_COUNT, &remoteThread );
#else // __arm64__
kr = thread_create_running( remoteTask, ARM_THREAD_STATE64, // ARM_THREAD_STATE64,
(thread_state_t) &remoteThreadState64.ts_64, ARM_THREAD_STATE64_COUNT , &remoteThread );

#endif
    if (kr != KERN_SUCCESS) { fprintf(stderr,"Unable to create remote thread: error %s", mach_error_string (kr));
                  return (-3); }

    return (0);
}

int main(int argc, const char *argv[])
{
    if (argc < 3) {
        fprintf(stderr, "Usage: %s _pid_ _action_\n", argv[0]);
        fprintf(stderr, "   _action_: path to a dylib on disk\n");
        exit(0);
    }

    pid_t pid = atoi(argv[1]);
    const char *action = argv[2];
    struct stat buf;

    int rc = stat(action, &buf);
    if (rc == 0) {
        inject(pid, action);
    }
    else {
        fprintf(stderr, "Dylib not found\n");
    }
}

and by the way maybe u know how to read login.keychain-db and dump all data ?

@1337kingOf @StarHack The requirements for app to be injectable on arm64 Mac's is:

1. No hardened runtime on the binary we're injecting into
2. Signed with get-task-allow entitlement

As long as those two requirements are fulfilled, you should not have problem to inject into the process. Just checked on my M1 on newest macOS and everything works just fine (beside crashing after code exec, but that's a different issue)

Edit: You don't need sudo.

@1337kingOf I got the same result. do u have resolved it?

@NeeSDev @1337kingOf @C0HERENCE I've just updated the code, so it won't crash. I've run some issues on closing thread, so i just put it in a loop, and it works. I don't have time for proper fix rn.

My first guess is that you've got task_for_pid on pid 37907: (os/kern) error is probably that either binary is signed with hardened-runtime or does not have get-task-allow entitlement.

Use this plit to sign binary: ldid -Sent.xml ./binary

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>com.apple.security.get-task-allow</key>
<true/>
</dict>
</plist>

Then it should work. Also try modifying your dylib into:

#include <stdio.h>
__attribute__((constructor))
static void testconstructor(int argc, const char **argv)
{
     printf("Hello World");
}

hey @vocaeq , excellent work with adapting this to arm, I have tried your very simple printf dylib, and also one that writes into a file, but it seems the code is not executed at all.
I compile the injector with gcc and the dylib with gcc or g++, with the -dynamiclib flag. I see no errors or crashes, the app continues to run, but it doesn't seem like my code is executed.
Would you happen to know why could it be?

@Szustarol Did you debug your app in lldb ?

lldb yourapp
r
CTRL+C
thread backtrace all
c

Then run injector (sudo or with privileged access).

CTRL+C
thread backtrace all

Did you see the new thread or is it missing altogether? We used a different implementation of this code in prouduction and it's working perfectly fine.

@StarHack thank you for your reply, yes indeed I checked that the thread is injected, however due to limitations in lldb (a longstanding EXC_BAD_ACCESS looping stop issue) I was only able to verify it in the resource monitor. That said, it's quite clear that the threads are created after running the injector a couple of times.

I am using this very simple source to test my injected dylib:

#include <iostream>
#include <fstream>


void appendToFile(const std::string& filePath, const std::string& text) {
  std::ofstream outfile;

  outfile.open(filePath, std::ios_base::app); 
  outfile << text; 
  outfile.flush();
}

__attribute__((constructor))
static void initializer(void) {        
    appendToFile("/tmp/injector.log", "HELLO FROM INJECTED CODE\n");
}
 
__attribute__((destructor))
static void finalizer(void) {                               
}
//g++ injector.cpp -dynamiclib -o inject.dylib

Of course, I ensured my /tmp has rwx permissions (well, on MacOs /tmp is actually a symlink that points to a 777 folder). Seems like the thread is injected, but the code is not running, and I cannot figure out a simpler way to debug a dylib than printing to a file, given access to lldb is not really available.
Do you maybe have some experience with why such a simple dylib would not work?

Edit: I managed to get lldb to work by recompiling it and disabling the EXC_BAD_ACCESS checks in code. I will fiddle with it and get back here if I find the issue.

Okay, it seems I have found the issue.
You of course need to get rid of C++ name mangling to create valid dylib entry points, so make sure to wrap your constructors and destructors with extern "C" if you're building your dylib in C++. Now my dylib can be injected with lldb, but it still doesn't work with your injector.

Thank you for sharing grate source code! It helps me a lot! I have been trying to inject my dylib to my process from scrach.

I have a question. How to check my dylib was loaded?

I compiled this code successfully then I started my target process which I made and I launched inject process with sudo.

There are no issues, no crashes but no logs. I saw some logs from 'inject' process and there were messages that the injeciting process was success.

---

Here is my dylib source code. I suposed happen showing log in my console with PID but no logs.

#include <stdio.h>
#include <unistd.h>

void print_pid()
{
    pid_t pid = getpid();
    printf("Current pid in sample libyrar: %d\n", pid);
}

__attribute__((constructor))
static void initialize()
{
    printf("Initializing sample library...\n");

    print_pid();
}

And here is logs from 'inject' process:

Allocated remote stack @0x102e30000
pthread_create_from_mach_thread @1961177f8
dlopen @19611dc04
pthread_exit @1961135cc
Remote Stack 64  0x102e38000, Remote code is 0x102e40000

Is this success to inject?

I'm so sorry. I passed wrong library path. I launched inject process in other folder then I passed relative path so the target process wasn't able to find my library.