ipc_kmsg_t
ipc_kobject_server(
ipc_kmsg_t request,
mach_msg_option_t __unused option)
{
mach_msg_size_t reply_size;
ipc_kmsg_t reply;
kern_return_t kr;
ipc_port_t *destp;
ipc_port_t replyp = IPC_PORT_NULL;
mach_msg_format_0_trailer_t *trailer;
mig_hash_t *ptr;
task_t task = TASK_NULL;
uint32_t exec_token;
boolean_t exec_token_changed = FALSE;
/*
* Find out corresponding mig_hash entry if any
*/
{
int key = request->ikm_header->msgh_id;
unsigned int i = (unsigned int)MIG_HASH(key);
int max_iter = mig_table_max_displ;
do {
ptr = &mig_buckets[i++ % MAX_MIG_ENTRIES];
} while (key != ptr->num && ptr->num && --max_iter);
if (!ptr->routine || key != ptr->num) {
ptr = (mig_hash_t *)0;
reply_size = mig_reply_size;
} else {
reply_size = ptr->size;
#if MACH_COUNTER
ptr->callcount++;
#endif
}
}
/* round up for trailer size */
reply_size += MAX_TRAILER_SIZE;
reply = ipc_kmsg_alloc(reply_size);
if (reply == IKM_NULL) {
printf("ipc_kobject_server: dropping request\n");
ipc_kmsg_trace_send(request, option);
ipc_kmsg_destroy(request);
return IKM_NULL;
}
/*
* Initialize reply message.
*/
{
#define InP ((mach_msg_header_t *) request->ikm_header)
#define OutP ((mig_reply_error_t *) reply->ikm_header)
/*
* MIG should really assure no data leakage -
* but until it does, pessimistically zero the
* whole reply buffer.
*/
bzero((void *)OutP, reply_size);
OutP->NDR = NDR_record;
OutP->Head.msgh_size = sizeof(mig_reply_error_t);
OutP->Head.msgh_bits =
MACH_MSGH_BITS_SET(MACH_MSGH_BITS_LOCAL(InP->msgh_bits), 0, 0, 0);
OutP->Head.msgh_remote_port = InP->msgh_local_port;
OutP->Head.msgh_local_port = MACH_PORT_NULL;
OutP->Head.msgh_voucher_port = MACH_PORT_NULL;
OutP->Head.msgh_id = InP->msgh_id + 100;
#undef InP
#undef OutP
}
/*
* Find the routine to call, and call it
* to perform the kernel function
*/
ipc_kmsg_trace_send(request, option);
{
if (ptr) {
/*
* Check if the port is a task port, if its a task port then
* snapshot the task exec token before the mig routine call.
*/
ipc_port_t port = request->ikm_header->msgh_remote_port;
if (IP_VALID(port) && ip_kotype(port) == IKOT_TASK) {
task = convert_port_to_task_with_exec_token(port, &exec_token);
}
(*ptr->routine)(request->ikm_header, reply->ikm_header);
/* Check if the exec token changed during the mig routine */
if (task != TASK_NULL) {
if (exec_token != task->exec_token) {
exec_token_changed = TRUE;
}
task_deallocate(task);
}
kernel_task->messages_received++;
}
else {
if (!ipc_kobject_notify(request->ikm_header, reply->ikm_header)){
#if DEVELOPMENT || DEBUG
printf("ipc_kobject_server: bogus kernel message, id=%d\n",
request->ikm_header->msgh_id);
#endif /* DEVELOPMENT || DEBUG */
_MIG_MSGID_INVALID(request->ikm_header->msgh_id);
((mig_reply_error_t *) reply->ikm_header)->RetCode
= MIG_BAD_ID;
}
else
kernel_task->messages_received++;
}
kernel_task->messages_sent++;
}
/*
* Destroy destination. The following code differs from
* ipc_object_destroy in that we release the send-once
* right instead of generating a send-once notification
* (which would bring us here again, creating a loop).
* It also differs in that we only expect send or
* send-once rights, never receive rights.
*
* We set msgh_remote_port to IP_NULL so that the kmsg
* destroy routines don't try to destroy the port twice.
*/
destp = (ipc_port_t *) &request->ikm_header->msgh_remote_port;
switch (MACH_MSGH_BITS_REMOTE(request->ikm_header->msgh_bits)) {
case MACH_MSG_TYPE_PORT_SEND:
ipc_port_release_send(*destp);
break;
case MACH_MSG_TYPE_PORT_SEND_ONCE:
ipc_port_release_sonce(*destp);
break;
default:
panic("ipc_kobject_server: strange destination rights");
}
*destp = IP_NULL;
/*
* Destroy voucher. The kernel MIG servers never take ownership
* of vouchers sent in messages. Swallow any such rights here.
*/
if (IP_VALID(request->ikm_voucher)) {
assert(MACH_MSG_TYPE_PORT_SEND ==
MACH_MSGH_BITS_VOUCHER(request->ikm_header->msgh_bits));
ipc_port_release_send(request->ikm_voucher);
request->ikm_voucher = IP_NULL;
}
if (!(reply->ikm_header->msgh_bits & MACH_MSGH_BITS_COMPLEX) &&
((mig_reply_error_t *) reply->ikm_header)->RetCode != KERN_SUCCESS)
kr = ((mig_reply_error_t *) reply->ikm_header)->RetCode;
else
kr = KERN_SUCCESS;
if ((kr == KERN_SUCCESS) || (kr == MIG_NO_REPLY)) {
/*
* The server function is responsible for the contents
* of the message. The reply port right is moved
* to the reply message, and we have deallocated
* the destination port right, so we just need
* to free the kmsg.
*/
ipc_kmsg_free(request);
} else {
/*
* The message contents of the request are intact.
* Destroy everthing except the reply port right,
* which is needed in the reply message.
*/
request->ikm_header->msgh_local_port = MACH_PORT_NULL;
ipc_kmsg_destroy(request);
}
replyp = (ipc_port_t)reply->ikm_header->msgh_remote_port;
if (kr == MIG_NO_REPLY) {
/*
* The server function will send a reply message
* using the reply port right, which it has saved.
*/
ipc_kmsg_free(reply);
return IKM_NULL;
} else if (!IP_VALID(replyp)) {
/*
* Can't queue the reply message if the destination
* (the reply port) isn't valid.
*/
ipc_kmsg_destroy(reply);
return IKM_NULL;
} else if (replyp->ip_receiver == ipc_space_kernel) {
/*
* Don't send replies to kobject kernel ports
*/
#if DEVELOPMENT || DEBUG
printf("%s: refusing to send reply to kobject %d port (id:%d)\n",
__func__, ip_kotype(replyp),
request->ikm_header->msgh_id);
#endif /* DEVELOPMENT || DEBUG */
ipc_kmsg_destroy(reply);
return IKM_NULL;
}
/* Fail the MIG call if the task exec token changed during the call */
if (kr == KERN_SUCCESS && exec_token_changed) {
/*
* Create a new reply msg with error and destroy the old reply msg.
*/
ipc_kmsg_t new_reply = ipc_kmsg_alloc(reply_size);
if (new_reply == IKM_NULL) {
printf("ipc_kobject_server: dropping request\n");
ipc_kmsg_destroy(reply);
return IKM_NULL;
}
/*
* Initialize the new reply message.
*/
{
#define OutP_new ((mig_reply_error_t *) new_reply->ikm_header)
#define OutP_old ((mig_reply_error_t *) reply->ikm_header)
bzero((void *)OutP_new, reply_size);
OutP_new->NDR = OutP_old->NDR;
OutP_new->Head.msgh_size = sizeof(mig_reply_error_t);
OutP_new->Head.msgh_bits = OutP_old->Head.msgh_bits & ~MACH_MSGH_BITS_COMPLEX;
OutP_new->Head.msgh_remote_port = OutP_old->Head.msgh_remote_port;
OutP_new->Head.msgh_local_port = MACH_PORT_NULL;
OutP_new->Head.msgh_voucher_port = MACH_PORT_NULL;
OutP_new->Head.msgh_id = OutP_old->Head.msgh_id;
/* Set the error as KERN_INVALID_TASK */
OutP_new->RetCode = KERN_INVALID_TASK;
#undef OutP_new
#undef OutP_old
}
/*
* Destroy everything in reply except the reply port right,
* which is needed in the new reply message.
*/
reply->ikm_header->msgh_remote_port = MACH_PORT_NULL;
ipc_kmsg_destroy(reply);
reply = new_reply;
}
trailer = (mach_msg_format_0_trailer_t *)
((vm_offset_t)reply->ikm_header + (int)reply->ikm_header->msgh_size);
trailer->msgh_sender = KERNEL_SECURITY_TOKEN;
trailer->msgh_trailer_type = MACH_MSG_TRAILER_FORMAT_0;
trailer->msgh_trailer_size = MACH_MSG_TRAILER_MINIMUM_SIZE;
return reply;
}
void do_service_mitm(mach_port_t real_service_port, mach_port_t replacer_portset) {
mach_msg_size_t max_request_size = 0x10000;
mach_msg_header_t* request = malloc(max_request_size);
for(;;) {
memset(request, 0, max_request_size);
kern_return_t err = mach_msg(request,
MACH_RCV_MSG |
MACH_RCV_LARGE, // leave larger messages in the queue
0,
max_request_size,
replacer_portset,
0,
0);
if (err == MACH_RCV_TOO_LARGE) {
// bump up the buffer size
mach_msg_size_t new_size = request->msgh_size + 0x1000;
request = realloc(request, new_size);
// try to receive again
continue;
}
if (err != KERN_SUCCESS) {
printf("error receiving on port set: %s\n", mach_error_string(err));
exit(EXIT_FAILURE);
}
got_replaced_with = request->msgh_local_port;
printf("got a request, fixing it up...\n");
// fix up the message such that it can be forwarded:
// get the rights we were sent for each port the header
mach_port_right_t remote = MACH_MSGH_BITS_REMOTE(request->msgh_bits);
mach_port_right_t voucher = MACH_MSGH_BITS_VOUCHER(request->msgh_bits);
// fixup the header ports:
// swap the remote port we received into the local port we'll forward
// this means we're only mitm'ing in one direction - we could also
// intercept these replies if necessary
request->msgh_local_port = request->msgh_remote_port;
request->msgh_remote_port = real_service_port;
// voucher port stays the same
int is_complex = MACH_MSGH_BITS_IS_COMPLEX(request->msgh_bits);
// (remote, local, voucher)
request->msgh_bits = MACH_MSGH_BITS_SET_PORTS(MACH_MSG_TYPE_COPY_SEND, right_fixup(remote), right_fixup(voucher));
if (is_complex) {
request->msgh_bits |= MACH_MSGH_BITS_COMPLEX;
// if it's complex we also need to fixup all the descriptors...
mach_msg_body_t* body = (mach_msg_body_t*)(request+1);
mach_msg_type_descriptor_t* desc = (mach_msg_type_descriptor_t*)(body+1);
for (mach_msg_size_t i = 0; i < body->msgh_descriptor_count; i++) {
switch (desc->type) {
case MACH_MSG_PORT_DESCRIPTOR: {
mach_msg_port_descriptor_t* port_desc = (mach_msg_port_descriptor_t*)desc;
inspect_port(port_desc->name);
port_desc->disposition = right_fixup(port_desc->disposition);
desc = (mach_msg_type_descriptor_t*)(port_desc+1);
break;
}
case MACH_MSG_OOL_VOLATILE_DESCRIPTOR:
case MACH_MSG_OOL_DESCRIPTOR: {
mach_msg_ool_descriptor_t* ool_desc = (mach_msg_ool_descriptor_t*)desc;
// make sure that deallocate is true; we don't want to keep this memory:
ool_desc->deallocate = 1;
desc = (mach_msg_type_descriptor_t*)(ool_desc+1);
break;
}
case MACH_MSG_OOL_PORTS_DESCRIPTOR: {
mach_msg_ool_ports_descriptor_t* ool_ports_desc = (mach_msg_ool_ports_descriptor_t*)desc;
// make sure that deallocate is true:
ool_ports_desc->deallocate = 1;
ool_ports_desc->disposition = right_fixup(ool_ports_desc->disposition);
desc = (mach_msg_type_descriptor_t*)(ool_ports_desc+1);
break;
}
}
}
}
printf("fixed up request, forwarding it\n");
// forward the message:
err = mach_msg(request,
MACH_SEND_MSG|MACH_MSG_OPTION_NONE,
request->msgh_size,
0,
MACH_PORT_NULL,
MACH_MSG_TIMEOUT_NONE,
MACH_PORT_NULL);
if (err != KERN_SUCCESS) {
printf("error forwarding service message: %s\n", mach_error_string(err));
exit(EXIT_FAILURE);
}
}
}
ipc_kmsg_t
ipc_kobject_server(
ipc_kmsg_t request)
{
mach_msg_size_t reply_size;
ipc_kmsg_t reply;
kern_return_t kr;
ipc_port_t *destp;
mach_msg_format_0_trailer_t *trailer;
register mig_hash_t *ptr;
/*
* Find out corresponding mig_hash entry if any
*/
{
register int key = request->ikm_header->msgh_id;
register int i = MIG_HASH(key);
register int max_iter = mig_table_max_displ;
do
ptr = &mig_buckets[i++ % MAX_MIG_ENTRIES];
while (key != ptr->num && ptr->num && --max_iter);
if (!ptr->routine || key != ptr->num) {
ptr = (mig_hash_t *)0;
reply_size = mig_reply_size;
} else {
reply_size = ptr->size;
#if MACH_COUNTER
ptr->callcount++;
#endif
}
}
/* round up for trailer size */
reply_size += MAX_TRAILER_SIZE;
reply = ipc_kmsg_alloc(reply_size);
if (reply == IKM_NULL) {
printf("ipc_kobject_server: dropping request\n");
ipc_kmsg_destroy(request);
return IKM_NULL;
}
/*
* Initialize reply message.
*/
{
#define InP ((mach_msg_header_t *) request->ikm_header)
#define OutP ((mig_reply_error_t *) reply->ikm_header)
/*
* MIG should really assure no data leakage -
* but until it does, pessimistically zero the
* whole reply buffer.
*/
bzero((void *)OutP, reply_size);
OutP->NDR = NDR_record;
OutP->Head.msgh_size = sizeof(mig_reply_error_t);
OutP->Head.msgh_bits =
MACH_MSGH_BITS_SET(MACH_MSGH_BITS_LOCAL(InP->msgh_bits), 0, 0, 0);
OutP->Head.msgh_remote_port = InP->msgh_local_port;
OutP->Head.msgh_local_port = MACH_PORT_NULL;
OutP->Head.msgh_voucher_port = MACH_PORT_NULL;
OutP->Head.msgh_id = InP->msgh_id + 100;
#undef InP
#undef OutP
}
/*
* Find the routine to call, and call it
* to perform the kernel function
*/
{
if (ptr) {
(*ptr->routine)(request->ikm_header, reply->ikm_header);
kernel_task->messages_received++;
}
else {
if (!ipc_kobject_notify(request->ikm_header, reply->ikm_header)){
#if MACH_IPC_TEST
printf("ipc_kobject_server: bogus kernel message, id=%d\n",
request->ikm_header->msgh_id);
#endif /* MACH_IPC_TEST */
_MIG_MSGID_INVALID(request->ikm_header->msgh_id);
((mig_reply_error_t *) reply->ikm_header)->RetCode
= MIG_BAD_ID;
}
else
kernel_task->messages_received++;
}
kernel_task->messages_sent++;
}
/*
* Destroy destination. The following code differs from
* ipc_object_destroy in that we release the send-once
* right instead of generating a send-once notification
* (which would bring us here again, creating a loop).
* It also differs in that we only expect send or
* send-once rights, never receive rights.
*
* We set msgh_remote_port to IP_NULL so that the kmsg
* destroy routines don't try to destroy the port twice.
*/
destp = (ipc_port_t *) &request->ikm_header->msgh_remote_port;
switch (MACH_MSGH_BITS_REMOTE(request->ikm_header->msgh_bits)) {
case MACH_MSG_TYPE_PORT_SEND:
ipc_port_release_send(*destp);
break;
case MACH_MSG_TYPE_PORT_SEND_ONCE:
ipc_port_release_sonce(*destp);
break;
default:
panic("ipc_kobject_server: strange destination rights");
}
*destp = IP_NULL;
/*
* Destroy voucher. The kernel MIG servers never take ownership
* of vouchers sent in messages. Swallow any such rights here.
*/
if (IP_VALID(request->ikm_voucher)) {
assert(MACH_MSG_TYPE_PORT_SEND ==
MACH_MSGH_BITS_VOUCHER(request->ikm_header->msgh_bits));
ipc_port_release_send(request->ikm_voucher);
request->ikm_voucher = IP_NULL;
}
if (!(reply->ikm_header->msgh_bits & MACH_MSGH_BITS_COMPLEX) &&
((mig_reply_error_t *) reply->ikm_header)->RetCode != KERN_SUCCESS)
kr = ((mig_reply_error_t *) reply->ikm_header)->RetCode;
else
kr = KERN_SUCCESS;
if ((kr == KERN_SUCCESS) || (kr == MIG_NO_REPLY)) {
/*
* The server function is responsible for the contents
* of the message. The reply port right is moved
* to the reply message, and we have deallocated
* the destination port right, so we just need
* to free the kmsg.
*/
ipc_kmsg_free(request);
} else {
/*
* The message contents of the request are intact.
* Destroy everthing except the reply port right,
* which is needed in the reply message.
*/
request->ikm_header->msgh_local_port = MACH_PORT_NULL;
ipc_kmsg_destroy(request);
}
if (kr == MIG_NO_REPLY) {
/*
* The server function will send a reply message
* using the reply port right, which it has saved.
*/
ipc_kmsg_free(reply);
return IKM_NULL;
} else if (!IP_VALID((ipc_port_t)reply->ikm_header->msgh_remote_port)) {
/*
* Can't queue the reply message if the destination
* (the reply port) isn't valid.
*/
ipc_kmsg_destroy(reply);
return IKM_NULL;
}
trailer = (mach_msg_format_0_trailer_t *)
((vm_offset_t)reply->ikm_header + (int)reply->ikm_header->msgh_size);
trailer->msgh_sender = KERNEL_SECURITY_TOKEN;
trailer->msgh_trailer_type = MACH_MSG_TRAILER_FORMAT_0;
trailer->msgh_trailer_size = MACH_MSG_TRAILER_MINIMUM_SIZE;
return reply;
}
