/*
* Copyright (c) 2000-2020 Apple Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. The rights granted to you under the License
* may not be used to create, or enable the creation or redistribution of,
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
*
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
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* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
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* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
/*
* @OSF_COPYRIGHT@
*/
/*
* Mach Operating System
* Copyright (c) 1991,1990,1989 Carnegie Mellon University
* All Rights Reserved.
*
* Permission to use, copy, modify and distribute this software and its
* documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie Mellon
* the rights to redistribute these changes.
*/
/*
* NOTICE: This file was modified by McAfee Research in 2004 to introduce
* support for mandatory and extensible security protections. This notice
* is included in support of clause 2.2 (b) of the Apple Public License,
* Version 2.0.
* Copyright (c) 2005-2006 SPARTA, Inc.
*/
/*
*/
/*
* File: ipc/ipc_object.c
* Author: Rich Draves
* Date: 1989
*
* Functions to manipulate IPC objects.
*/
#include <mach/mach_types.h>
#include <mach/boolean.h>
#include <mach/kern_return.h>
#include <mach/port.h>
#include <mach/message.h>
#include <kern/kern_types.h>
#include <kern/misc_protos.h>
#include <kern/ipc_kobject.h>
#include <kern/zalloc_internal.h> // zone_id_for_element
#include <ipc/ipc_types.h>
#include <ipc/ipc_importance.h>
#include <ipc/port.h>
#include <ipc/ipc_space.h>
#include <ipc/ipc_entry.h>
#include <ipc/ipc_object.h>
#include <ipc/ipc_hash.h>
#include <ipc/ipc_kmsg.h>
#include <ipc/ipc_right.h>
#include <ipc/ipc_notify.h>
#include <ipc/ipc_policy.h>
#include <ipc/ipc_port.h>
#include <ipc/ipc_pset.h>
#include <security/mac_mach_internal.h>
static struct mpsc_daemon_queue ipc_object_deallocate_queue;
/*
* In order to do lockfree lookups in the IPC space, we combine two schemes:
*
* - the ipc table pointer is protected with hazard pointers to allow
* dereferencing it with only holding a ref on a task or space;
*
* - we use ipc_object_lock_allow_invalid in order to lock locks and validate
* that they are the droid we're looking for.
*
* The second half requires that virtual addresses assigned that ever held
* a port, either hold a port, or nothing, forever. To get this property,
* we just piggy back on the zone sequestering security feature which gives
* us exactly that.
*
* However, sequestering really only "works" on a sufficiently large address
* space, especially for a resource that can be made by userspace at will,
* so we can't do lockless lookups on ILP32.
*
* Note: this scheme is incompatible with kasan quarantines
* (because it uses elements to store backtraces in them
* which lets the waitq lock appear "valid" by accident when
* elements are freed).
*/
#define IPC_OBJECT_ZC_BASE (ZC_ZFREE_CLEARMEM | ZC_SEQUESTER)
ZONE_DEFINE_ID(ZONE_ID_IPC_PORT, "ipc ports", struct ipc_port,
IPC_OBJECT_ZC_BASE | ZC_CACHING);
ZONE_DEFINE_ID(ZONE_ID_IPC_PORT_SET, "ipc port sets", struct ipc_pset,
IPC_OBJECT_ZC_BASE);
__attribute__((noinline))
static void
ipc_object_free(ipc_object_t object)
{
if (io_is_any_port(object)) {
ipc_port_free(ip_object_to_port(object));
} else {
ipc_pset_free(ips_object_to_pset(object));
}
}
__attribute__((noinline))
static void
ipc_object_free_safe(ipc_object_t object)
{
struct waitq *wq = io_waitq(object);
assert(!waitq_is_valid(wq));
assert(os_atomic_load(&wq->waitq_defer.mpqc_next, relaxed) == NULL);
mpsc_daemon_enqueue(&ipc_object_deallocate_queue,
&wq->waitq_defer, MPSC_QUEUE_NONE);
}
static void
ipc_object_deallocate_queue_invoke(mpsc_queue_chain_t e,
__assert_only mpsc_daemon_queue_t dq)
{
struct waitq *wq = __container_of(e, struct waitq, waitq_defer);
ipc_object_t io = io_from_waitq(wq);
assert(dq == &ipc_object_deallocate_queue);
os_atomic_store(&wq->waitq_defer.mpqc_next, NULL, relaxed);
ipc_object_free(io);
}
void
ipc_object_deallocate_register_queue(void)
{
thread_deallocate_daemon_register_queue(&ipc_object_deallocate_queue,
ipc_object_deallocate_queue_invoke);
}
/*
* Routine: ipc_object_reference
* Purpose:
* Take a reference to an object.
*/
void
ipc_object_reference(
ipc_object_t io)
{
static_assert(sizeof(os_ref_atomic_t) == sizeof(io->io_references));
os_ref_retain_raw(&io->io_references, NULL);
}
/*
* Routine: ipc_object_release
* Purpose:
* Release a reference to an object.
*/
void
ipc_object_release(
ipc_object_t io)
{
#if DEBUG
assert(get_preemption_level() == 0);
#endif
if (os_ref_release_raw(&io->io_references, NULL) == 0) {
/* Free the object */
ipc_object_free(io);
}
}
/*
* Routine: ipc_object_release_safe
* Purpose:
* Release a reference to an object safely
*/
void
ipc_object_release_safe(
ipc_object_t io)
{
if (os_ref_release_raw(&io->io_references, NULL) == 0) {
if (get_preemption_level() == 0) {
ipc_object_free(io);
} else {
ipc_object_free_safe(io);
}
}
}
/*
* Routine: ipc_object_release_live
* Purpose:
* Release a reference to an object that isn't the last one.
*/
void
ipc_object_release_live(
ipc_object_t io)
{
os_ref_release_live_raw(&io->io_references, NULL);
}
/*
* Routine: ipc_object_translate
* Purpose:
* Look up an object in a space.
* Conditions:
* Nothing locked before. If successful, the object
* is returned active and locked. The caller doesn't get a ref.
* Returns:
* KERN_SUCCESS Object returned locked.
* KERN_INVALID_TASK The space is dead.
* KERN_INVALID_NAME The name doesn't denote a right
* KERN_INVALID_RIGHT Name doesn't denote the correct right
*/
kern_return_t
ipc_object_translate(
ipc_space_t space,
mach_port_name_t name,
mach_port_right_t right,
ipc_object_t *objectp)
{
ipc_entry_bits_t bits;
ipc_object_t object;
kern_return_t kr;
if (!MACH_PORT_RIGHT_VALID_TRANSLATE(right)) {
return KERN_INVALID_RIGHT;
}
kr = ipc_right_lookup_read(space, name, &bits, &object);
if (kr != KERN_SUCCESS) {
return kr;
}
/* object is locked and active */
if ((bits & MACH_PORT_TYPE(right)) == MACH_PORT_TYPE_NONE) {
io_unlock(object);
return KERN_INVALID_RIGHT;
}
*objectp = object;
return KERN_SUCCESS;
}
/*
* Routine: ipc_object_translate_pset_receive
* Purpose:
* Look up two objects in a space (a port set and a receive right)
* Conditions:
* Nothing locked before. If successful, the objects
* are returned locked. The caller doesn't get a ref.
* Returns:
* KERN_SUCCESS Objects returned locked.
* KERN_INVALID_TASK The space is dead.
* KERN_INVALID_NAME A name doesn't denote a right.
* KERN_INVALID_RIGHT A name doesn't denote the correct right.
*/
kern_return_t
ipc_object_translate_port_pset(
ipc_space_t space,
mach_port_name_t port_name,
ipc_port_t *portp,
mach_port_name_t pset_name,
ipc_pset_t *psetp)
{
ipc_entry_t port_entry;
ipc_entry_t pset_entry;
ipc_port_t port;
ipc_pset_t pset;
kern_return_t kr;
kr = ipc_right_lookup_two_read(space,
port_name, &port_entry, pset_name, &pset_entry);
if (kr != KERN_SUCCESS) {
return kr;
}
/* space is read-locked and active */
if ((port_entry->ie_bits & MACH_PORT_TYPE_RECEIVE) == 0) {
bool guard = !(port_entry->ie_bits & IE_BITS_EX_RECEIVE);
is_read_unlock(space);
if (guard) {
mach_port_guard_exception(port_name,
MPG_PAYLOAD(MPG_FLAGS_INVALID_RIGHT_TRANSLATE_PORT,
port_entry->ie_bits),
kGUARD_EXC_INVALID_RIGHT);
}
return KERN_INVALID_RIGHT;
}
if ((pset_entry->ie_bits & MACH_PORT_TYPE_PORT_SET) == 0) {
is_read_unlock(space);
mach_port_guard_exception(pset_name,
MPG_PAYLOAD(MPG_FLAGS_INVALID_RIGHT_TRANSLATE_PSET,
pset_entry->ie_bits),
kGUARD_EXC_INVALID_RIGHT);
return KERN_INVALID_RIGHT;
}
port = port_entry->ie_port;
assert(port != IP_NULL);
ip_mq_lock(port);
if (!ip_active(port)) {
ip_mq_unlock(port);
is_read_unlock(space);
return KERN_INVALID_NAME;
}
pset = pset_entry->ie_pset;
assert(pset != IPS_NULL);
ips_mq_lock(pset);
if (!ips_active(pset)) {
ip_mq_unlock(port);
ips_mq_unlock(pset);
is_read_unlock(space);
return KERN_INVALID_NAME;
}
*portp = port;
*psetp = pset;
is_read_unlock(space);
return KERN_SUCCESS;
}
/*
* Routine: ipc_object_alloc_dead
* Purpose:
* Allocate a dead-name entry.
* Conditions:
* Nothing locked.
* Returns:
* KERN_SUCCESS The dead name is allocated.
* KERN_INVALID_TASK The space is dead.
* KERN_NO_SPACE No room for an entry in the space.
*/
kern_return_t
ipc_object_alloc_dead(
ipc_space_t space,
mach_port_name_t *namep)
{
ipc_entry_t entry;
kern_return_t kr;
mach_port_type_t type = MACH_PORT_TYPE_DEAD_NAME;
mach_port_urefs_t urefs = 1;
kr = ipc_entry_alloc(space, IPC_OBJECT_NULL, namep, &entry);
if (kr != KERN_SUCCESS) {
return kr;
}
/* space is write-locked */
ipc_entry_init(space, IPC_OBJECT_NULL, type, entry, urefs, *namep);
is_write_unlock(space);
return KERN_SUCCESS;
}
/*
* Routine: ipc_object_alloc_entry
* Purpose:
* Allocate an unitialized entry for a new object.
* That entry must later be initialized by `ipc_entry_init` after
* the object has been initialized
* Conditions:
* Nothing locked.
* The space is write locked on successful return.
* Returns:
* KERN_SUCCESS The object is allocated.
* KERN_INVALID_TASK The space is dead.
* KERN_NO_SPACE No room for an entry in the space.
*/
kern_return_t
ipc_object_alloc_entry(
ipc_space_t space,
ipc_object_t object,
mach_port_name_t *namep,
ipc_entry_t *entry)
{
kern_return_t kr;
kr = ipc_entry_alloc(space, object, namep, entry);
return kr;
}
/*
* Routine: ipc_object_alloc_entry_with_name
* Purpose:
* Allocate an uninitalized entry for a new object, with a specific name.
* That entry must later be initialized by `ipc_entry_init` after
* the object has been initialized
* Conditions:
* Nothing locked.
* The space is write locked on successful return.
*
* Returns:
* KERN_SUCCESS The object is allocated.
* KERN_INVALID_TASK The space is dead.
* KERN_NAME_EXISTS The name already denotes a right.
*/
kern_return_t
ipc_object_alloc_entry_with_name(
ipc_space_t space,
mach_port_name_t name,
ipc_entry_t *entry)
{
kern_return_t kr;
kr = ipc_entry_alloc_name(space, name, entry);
if (kr == KERN_SUCCESS && ipc_right_inuse(*entry)) {
is_write_unlock(space);
kr = KERN_NAME_EXISTS;
}
return kr;
}
/* Routine: ipc_object_validate
* Purpose:
* Validates an ipc port or port set as belonging to the correct
* zone.
*/
void
ipc_object_validate(
ipc_object_t object,
ipc_object_type_t type)
{
if (io_is_any_port_type(type)) {
ip_validate(object);
} else {
ips_validate(object);
}
}
/*
* Routine: ipc_object_copyin_type
* Purpose:
* Convert a send type name to a received type name.
*/
mach_msg_type_name_t
ipc_object_copyin_type(
mach_msg_type_name_t msgt_name)
{
switch (msgt_name) {
case MACH_MSG_TYPE_MOVE_RECEIVE:
return MACH_MSG_TYPE_PORT_RECEIVE;
case MACH_MSG_TYPE_MOVE_SEND_ONCE:
case MACH_MSG_TYPE_MAKE_SEND_ONCE:
return MACH_MSG_TYPE_PORT_SEND_ONCE;
case MACH_MSG_TYPE_MOVE_SEND:
case MACH_MSG_TYPE_MAKE_SEND:
case MACH_MSG_TYPE_COPY_SEND:
return MACH_MSG_TYPE_PORT_SEND;
default:
return MACH_MSG_TYPE_PORT_NONE;
}
}
/*
* Routine: ipc_object_copyin
* Purpose:
* Copyin a capability from a space.
* If successful, the caller gets a ref
* for the resulting port, unless it is IO_DEAD.
* Conditions:
* Nothing locked.
* Returns:
* KERN_SUCCESS Acquired a port, possibly IP_DEAD.
* KERN_INVALID_TASK The space is dead.
* KERN_INVALID_NAME Name doesn't exist in space.
* KERN_INVALID_RIGHT Name doesn't denote correct right.
*/
kern_return_t
ipc_object_copyin(
ipc_space_t space,
mach_port_name_t name,
mach_msg_type_name_t msgt_name,
ipc_object_copyin_flags_t copyin_flags,
ipc_copyin_op_t copyin_reason,
mach_msg_guarded_port_descriptor_t *gdesc,
ipc_port_t *portp)
{
ipc_copyin_rcleanup_t icrc;
ipc_copyin_cleanup_t icc;
ipc_entry_t entry;
kern_return_t kr;
ipc_object_copyin_flags_t copyin_mask = IPC_OBJECT_COPYIN_FLAGS_ALLOW_IMMOVABLE_SEND;
copyin_mask = (copyin_flags & copyin_mask) | IPC_OBJECT_COPYIN_FLAGS_DEADOK;
/*
* Could first try a read lock when doing
* MACH_MSG_TYPE_COPY_SEND, MACH_MSG_TYPE_MAKE_SEND,
* and MACH_MSG_TYPE_MAKE_SEND_ONCE.
*/
ipc_right_copyin_rcleanup_init(&icrc, gdesc);
kr = ipc_right_lookup_write(space, name, &entry);
if (kr != KERN_SUCCESS) {
return kr;
}
/* space is write-locked and active */
kr = ipc_right_copyin(space, name, msgt_name, copyin_mask, copyin_reason,
entry, portp, &icc, &icrc);
is_write_unlock(space);
ipc_right_copyin_cleanup_destroy(&icc, name);
ipc_right_copyin_rcleanup_destroy(&icrc);
if (IP_VALID(*portp) &&
ip_type(*portp) == IOT_SERVICE_PORT &&
msgt_name == MACH_MSG_TYPE_MOVE_RECEIVE &&
!task_is_initproc(space->is_task) &&
!ipc_space_has_telemetry_type(space, IS_HAS_SERVICE_PORT_TELEMETRY)) {
ipc_stash_policy_violations_telemetry(IPCPV_MOVE_SERVICE_PORT,
*portp, name);
}
return kr;
}
/*
* Routine: ipc_object_copyin_from_kernel
* Purpose:
* Copyin a naked capability from the kernel.
*
* MACH_MSG_TYPE_MOVE_RECEIVE
* The receiver must be ipc_space_kernel
* or the receive right must already be in limbo.
* Consumes the naked receive right.
* MACH_MSG_TYPE_COPY_SEND
* A naked send right must be supplied.
* The port gains a reference, and a send right
* if the port is still active.
* MACH_MSG_TYPE_MAKE_SEND
* The receiver must be ipc_space_kernel.
* The port gains a reference and a send right.
* MACH_MSG_TYPE_MOVE_SEND
* Consumes a naked send right.
* MACH_MSG_TYPE_MAKE_SEND_ONCE
* The port gains a reference and a send-once right.
* Receiver also be the caller of device subsystem,
* so no assertion.
* MACH_MSG_TYPE_MOVE_SEND_ONCE
* Consumes a naked send-once right.
* Conditions:
* Nothing locked.
*/
void
ipc_object_copyin_from_kernel(
ipc_port_t port,
mach_msg_type_name_t msgt_name)
{
ipc_object_label_t label;
assert(IP_VALID(port));
switch (msgt_name) {
case MACH_MSG_TYPE_MOVE_RECEIVE:
label = ip_mq_lock_label_get(port);
if (label.io_state == IO_STATE_IN_SPACE) {
assert(ip_in_space(port, ipc_space_kernel));
/*
* Ports in kernel are never hooked to a pset,
* so we don't need to pass a waitq linkage free list.
*/
ipc_port_mark_in_limbo(port, &label, NULL);
ip_mq_unlock(port);
} else {
ipc_release_assert(io_state_in_limbo(label.io_state));
ip_mq_unlock_label_put(port, &label);
}
break;
case MACH_MSG_TYPE_COPY_SEND:
ip_mq_lock(port);
if (ip_active(port)) {
assert(port->ip_srights > 0);
}
ip_srights_inc(port);
ip_reference(port);
ip_mq_unlock(port);
break;
case MACH_MSG_TYPE_MAKE_SEND:
ip_mq_lock(port);
if (ip_active(port)) {
assert(ip_in_a_space(port));
assert(ip_in_space(port, ipc_space_kernel));
port->ip_mscount++;
}
ip_srights_inc(port);
ip_reference(port);
ip_mq_unlock(port);
break;
case MACH_MSG_TYPE_MOVE_SEND:
/* move naked send right into the message */
assert(port->ip_srights);
break;
case MACH_MSG_TYPE_MAKE_SEND_ONCE:
ip_mq_lock(port);
if (ip_active(port)) {
assert(ip_in_a_space(port));
}
ipc_port_make_sonce_locked(port);
ip_mq_unlock(port);
break;
case MACH_MSG_TYPE_MOVE_SEND_ONCE:
/* move naked send-once right into the message */
assert(port->ip_sorights);
break;
default:
ipc_unreachable("ipc_object_copyin_from_kernel: strange rights");
}
}
/*
* Routine: ipc_object_destroy
* Purpose:
* Destroys a naked capability.
* Consumes a ref for the port.
*
* A receive right should be in limbo or in transit.
* Conditions:
* Nothing locked.
*/
void
ipc_object_destroy(
ipc_port_t port,
mach_msg_type_name_t msgt_name)
{
assert(IP_VALID(port));
switch (msgt_name) {
case MACH_MSG_TYPE_PORT_SEND:
ipc_port_release_send(port);
break;
case MACH_MSG_TYPE_PORT_SEND_ONCE:
ip_mq_lock(port);
ipc_notify_send_once_and_unlock(port);
break;
case MACH_MSG_TYPE_PORT_RECEIVE:
ipc_port_release_receive(port);
break;
default:
ipc_unreachable("ipc_object_destroy: strange rights");
}
}
/*
* Routine: ipc_object_destroy_dest
* Purpose:
* Destroys a naked capability for the destination of
* of a message. Consumes a ref for the port.
*
* Conditions:
* Nothing locked.
*/
void
ipc_object_destroy_dest(
ipc_port_t port,
mach_msg_type_name_t msgt_name)
{
assert(IP_VALID(port));
switch (msgt_name) {
case MACH_MSG_TYPE_PORT_SEND:
ipc_port_release_send(port);
break;
case MACH_MSG_TYPE_PORT_SEND_ONCE:
ip_mq_lock(port);
ipc_notify_send_once_and_unlock(port);
break;
default:
ipc_unreachable("ipc_object_destroy_dest: strange rights");
}
}
/*
* Routine: ipc_object_insert_send_right
* Purpose:
* Insert a send right into an object already in the space.
* The specified name must already point to a valid object.
*
* Note: This really is a combined copyin()/copyout(),
* that avoids most of the overhead of being implemented that way.
*
* This is the fastpath for mach_port_insert_right.
*
* Conditions:
* Nothing locked.
*
* msgt_name must be MACH_MSG_TYPE_MAKE_SEND or
* MACH_MSG_TYPE_COPY_SEND.
*
* Returns:
* KERN_SUCCESS Copied out object, consumed ref.
* KERN_INVALID_TASK The space is dead.
* KERN_INVALID_NAME Name doesn't exist in space.
* KERN_INVALID_CAPABILITY The object is dead.
* KERN_RIGHT_EXISTS Space has rights under another name.
*/
kern_return_t
ipc_object_insert_send_right(
ipc_space_t space,
mach_port_name_t name,
mach_msg_type_name_t msgt_name)
{
ipc_entry_bits_t bits;
ipc_object_t object;
ipc_entry_t entry;
ipc_port_t port;
kern_return_t kr;
assert(msgt_name == MACH_MSG_TYPE_MAKE_SEND ||
msgt_name == MACH_MSG_TYPE_COPY_SEND);
kr = ipc_right_lookup_write(space, name, &entry);
if (kr != KERN_SUCCESS) {
return kr;
}
/* space is write-locked and active */
bits = entry->ie_bits;
object = entry->ie_object;
if (object == IPC_OBJECT_NULL) {
is_write_unlock(space);
return KERN_INVALID_CAPABILITY;
}
if ((bits & MACH_PORT_TYPE_PORT_RIGHTS) == 0) {
is_write_unlock(space);
return KERN_INVALID_RIGHT;
}
port = ip_object_to_port(object);
ip_mq_lock(port);
if (!ip_active(port)) {
kr = KERN_INVALID_CAPABILITY;
} else if (msgt_name == MACH_MSG_TYPE_MAKE_SEND) {
if (bits & MACH_PORT_TYPE_RECEIVE) {
port->ip_mscount++;
if ((bits & MACH_PORT_TYPE_SEND) == 0) {
ip_srights_inc(port);
bits |= MACH_PORT_TYPE_SEND;
}
/* leave urefs pegged to maximum if it overflowed */
if (IE_BITS_UREFS(bits) < MACH_PORT_UREFS_MAX) {
bits += 1; /* increment urefs */
}
entry->ie_bits = bits;
ipc_entry_modified(space, name, entry);
kr = KERN_SUCCESS;
} else {
kr = KERN_INVALID_RIGHT;
}
} else { // MACH_MSG_TYPE_COPY_SEND
if (bits & MACH_PORT_TYPE_SEND) {
/* leave urefs pegged to maximum if it overflowed */
if (IE_BITS_UREFS(bits) < MACH_PORT_UREFS_MAX) {
entry->ie_bits = bits + 1; /* increment urefs */
}
ipc_entry_modified(space, name, entry);
kr = KERN_SUCCESS;
} else {
kr = KERN_INVALID_RIGHT;
}
}
ip_mq_unlock(port);
is_write_unlock(space);
return kr;
}
/*
* Routine: ipc_object_copyout
* Purpose:
* Copyout a capability, placing it into a space.
* Always consumes a ref for the port.
* Conditions:
* Nothing locked.
* Returns:
* KERN_SUCCESS Copied out port, consumed ref.
* KERN_INVALID_TASK The space is dead.
* KERN_INVALID_CAPABILITY The port is dead.
* KERN_NO_SPACE No room in space for another right.
* KERN_UREFS_OVERFLOW Urefs limit exceeded
* and overflow wasn't specified.
*/
kern_return_t
ipc_object_copyout(
ipc_space_t space,
ipc_port_t port,
mach_msg_type_name_t msgt_name,
ipc_object_copyout_flags_t flags,
mach_msg_guarded_port_descriptor_t *gdesc,
mach_port_name_t *namep)
{
struct knote *kn = current_thread()->ith_knote;
ipc_object_label_t label;
mach_port_name_t name;
ipc_entry_t entry;
kern_return_t kr;
assert(IP_VALID(port));
if (ITH_KNOTE_VALID(kn, msgt_name)) {
filt_machport_turnstile_prepare_lazily(kn, msgt_name, port);
}
is_write_lock(space);
for (;;) {
ipc_port_t port_subst = IP_NULL;
if (!is_active(space)) {
is_write_unlock(space);
kr = KERN_INVALID_TASK;
goto out;
}
kr = ipc_entries_hold(space, 1);
if (kr != KERN_SUCCESS) {
/* unlocks/locks space, so must start again */
kr = ipc_entry_grow_table(space, ITS_SIZE_NONE);
if (kr != KERN_SUCCESS) {
/* space is unlocked */
goto out;
}
continue;
}
label = ip_mq_lock_check_aligned(port);
/* Don't actually copyout rights we aren't allowed to */
if (!io_state_active(label.io_state) ||
!ip_label_check_or_substitute(space, port, &label,
msgt_name, &port_subst)) {
ip_mq_unlock_label_put(port, &label);
is_write_unlock(space);
assert(port_subst == IP_NULL);
kr = KERN_INVALID_CAPABILITY;
goto out;
}
/* is the kolabel requesting a substitution */
if (port_subst != IP_NULL) {
/*
* port is unlocked, its right consumed
* space is unlocked
*/
assert(msgt_name == MACH_MSG_TYPE_PORT_SEND);
port = port_subst;
if (!IP_VALID(port)) {
port = IP_DEAD;
kr = KERN_INVALID_CAPABILITY;
goto out;
}
is_write_lock(space);
continue;
}
break;
}
/* space is write-locked and active, port is locked and active */
if ((msgt_name != MACH_MSG_TYPE_PORT_SEND_ONCE) &&
ipc_right_reverse(space, port, &name, &entry)) {
assert(entry->ie_bits & MACH_PORT_TYPE_SEND_RECEIVE);
} else {
ipc_entry_claim(space, ip_to_object(port), &name, &entry);
}
if (msgt_name == MACH_MSG_TYPE_PORT_RECEIVE) {
ipc_right_copyout_recv_and_unlock_space(space, port, &label,
name, entry, gdesc);
} else {
ip_label_put(port, &label);
ipc_right_copyout_any_send(space, port, msgt_name,
flags, name, entry);
is_write_unlock(space);
}
/* port is unlocked */
out:
if (kr == KERN_SUCCESS) {
*namep = name;
} else if (IP_VALID(port)) {
ipc_object_destroy(port, msgt_name);
}
return kr;
}
/*
* Routine: ipc_object_copyout_name
* Purpose:
* Copyout a capability, placing it into a space.
* The specified name is used for the capability.
* If successful, consumes a ref for the port.
* Conditions:
* Nothing locked.
* Returns:
* KERN_SUCCESS Copied out port, consumed ref.
* KERN_INVALID_TASK The space is dead.
* KERN_INVALID_CAPABILITY The port is dead.
* KERN_UREFS_OVERFLOW Urefs limit exceeded
* and overflow wasn't specified.
* KERN_RIGHT_EXISTS Space has rights under another name.
* KERN_NAME_EXISTS Name is already used.
* KERN_INVALID_VALUE Supplied port name is invalid.
*/
kern_return_t
ipc_object_copyout_name(
ipc_space_t space,
ipc_port_t port,
mach_msg_type_name_t msgt_name,
mach_port_name_t name)
{
ipc_object_label_t label;
mach_port_name_t oname;
ipc_entry_t oentry;
ipc_entry_t entry;
kern_return_t kr;
#if IMPORTANCE_INHERITANCE
int assertcnt = 0;
ipc_importance_task_t task_imp = IIT_NULL;
#endif /* IMPORTANCE_INHERITANCE */
assert(IP_VALID(port));
kr = ipc_entry_alloc_name(space, name, &entry);
if (kr != KERN_SUCCESS) {
return kr;
}
/* space is write-locked and active */
label = ip_mq_lock_check_aligned(port);
/*
* Don't actually copyout rights we aren't allowed to
*
* In particular, kolabel-ed ports do not allow callers
* to pick the name they end up with.
*/
if (!io_state_active(label.io_state) ||
(io_is_kobject_type(label.io_type) && label.iol_kobject)) {
ip_mq_unlock_label_put(port, &label);
if (!ipc_right_inuse(entry)) {
ipc_entry_dealloc(space, IPC_OBJECT_NULL, name, entry);
}
is_write_unlock(space);
return KERN_INVALID_CAPABILITY;
}
/* space is write-locked and active, port is locked and active */
if ((msgt_name != MACH_MSG_TYPE_PORT_SEND_ONCE) &&
ipc_right_reverse(space, port, &oname, &oentry)) {
if (name != oname) {
ip_mq_unlock_label_put(port, &label);
if (!ipc_right_inuse(entry)) {
ipc_entry_dealloc(space, IPC_OBJECT_NULL, name, entry);
}
is_write_unlock(space);
return KERN_RIGHT_EXISTS;
}
assert(entry == oentry);
assert(entry->ie_bits & MACH_PORT_TYPE_SEND_RECEIVE);
} else if (ipc_right_inuse(entry)) {
ip_mq_unlock_label_put(port, &label);
is_write_unlock(space);
return KERN_NAME_EXISTS;
} else {
assert(entry->ie_port == IP_NULL);
entry->ie_port = port;
}
if (msgt_name == MACH_MSG_TYPE_PORT_RECEIVE) {
#if IMPORTANCE_INHERITANCE
/*
* We are slamming a receive right into the space, without
* first having been enqueued on a port destined there. So,
* we have to arrange to boost the task appropriately if this
* port has assertions (and the task wants them).
*/
if (space->is_task != TASK_NULL) {
task_imp = space->is_task->task_imp_base;
if (ipc_importance_task_is_any_receiver_type(task_imp)) {
assertcnt = port->ip_impcount;
ipc_importance_task_reference(task_imp);
} else {
task_imp = IIT_NULL;
}
}
/* take port out of limbo */
port->ip_tempowner = 0;
#endif /* IMPORTANCE_INHERITANCE */
ipc_right_copyout_recv_and_unlock_space(space, port, &label,
name, entry, NULL);
} else {
ip_label_put(port, &label);
ipc_right_copyout_any_send(space, port, msgt_name,
IPC_OBJECT_COPYOUT_FLAGS_NONE, name, entry);
is_write_unlock(space);
}
#if IMPORTANCE_INHERITANCE
/*
* Add the assertions to the task that we captured before
*/
if (task_imp != IIT_NULL) {
ipc_importance_task_hold_internal_assertion(task_imp, assertcnt);
ipc_importance_task_release(task_imp);
}
#endif /* IMPORTANCE_INHERITANCE */
return KERN_SUCCESS;
}
/*
* Routine: ipc_object_copyout_dest
* Purpose:
* Translates/consumes the destination right of a message.
* This is unlike normal copyout because the right is consumed
* in a funny way instead of being given to the receiving space.
* The receiver gets his name for the port, if he has receive
* rights, otherwise MACH_PORT_NULL.
* Conditions:
* The port is locked and active. Nothing else locked.
* The port is unlocked and loses a reference.
*/
void
ipc_object_copyout_dest(
ipc_space_t space,
ipc_port_t port,
mach_msg_type_name_t msgt_name,
mach_port_name_t *namep)
{
mach_port_name_t name;
assert(IP_VALID(port));
assert(ip_active(port));
/*
* If the space is the receiver/owner of the port,
* then we quietly consume the right and return
* the space's name for the port. Otherwise
* we destroy the right and return MACH_PORT_NULL.
*/
switch (msgt_name) {
case MACH_MSG_TYPE_PORT_SEND: {
ipc_notify_nsenders_t nsrequest = { };
if (ip_in_space(port, space)) {
name = ip_get_receiver_name(port);
} else {
name = MACH_PORT_NULL;
}
ip_srights_dec(port);
if (port->ip_srights == 0) {
nsrequest = ipc_notify_no_senders_prepare(port);
}
ipc_port_clear_sync_rcv_thread_boost_locked(port);
/* port unlocked */
ipc_notify_no_senders_emit(nsrequest);
ip_release(port);
break;
}
case MACH_MSG_TYPE_PORT_SEND_ONCE: {
if (ip_in_space(port, space)) {
/* quietly consume the send-once right */
ip_sorights_dec(port);
name = ip_get_receiver_name(port);
ipc_port_clear_sync_rcv_thread_boost_locked(port);
/* port unlocked */
ip_release(port);
} else {
/*
* A very bizarre case. The message
* was received, but before this copyout
* happened the space lost receive rights.
* We can't quietly consume the soright
* out from underneath some other task,
* so generate a send-once notification.
*/
ipc_notify_send_once_and_unlock(port);
name = MACH_PORT_NULL;
}
break;
}
default:
ipc_unreachable("ipc_object_copyout_dest: strange rights");
}
*namep = name;
}
void
ipc_object_unpin(
ipc_space_t space,
ipc_port_t port)
{
mach_port_name_t name;
ipc_entry_t entry;
if (IP_VALID(port)) {
is_write_lock(space);
ip_mq_lock(port);
if (is_active(space) &&
ipc_right_reverse(space, port, &name, &entry) &&
(entry->ie_bits & IE_BITS_PINNED_SEND)) {
assert(entry->ie_bits & MACH_PORT_TYPE_SEND);
entry->ie_bits &= ~IE_BITS_PINNED_SEND;
ipc_entry_modified(space, name, entry);
}
ip_mq_unlock(port);
is_write_unlock(space);
}
}
static_assert(offsetof(struct ipc_object_waitq, iowq_waitq) ==
offsetof(struct ipc_port, ip_waitq));
static_assert(offsetof(struct ipc_object_waitq, iowq_waitq) ==
offsetof(struct ipc_pset, ips_wqset));
__abortlike
static void
ipc_object_validate_preflight_panic(ipc_object_t io)
{
panic("ipc object %p is neither a port or a port-set", io);
}
/*
* Routine: ipc_object_lock_allow_invalid
* Purpose:
* Speculatively try to lock an object in an undefined state.
*
* This relies on the fact that IPC object memory is allocated
* from sequestered zones, so at a given address, one can find:
* 1. a valid object,
* 2. a freed or invalid (uninitialized) object,
* 3. unmapped memory.
*
* (2) is possible because the zone is made with ZC_ZFREE_CLEARMEM which
* ensures freed elements are always zeroed.
*
* (3) is a direct courtesy of waitq_lock_allow_invalid().
*
* In order to disambiguate (1) from (2), we use the "waitq valid"
* bit which is part of the lock. When that bit is absent,
* waitq_lock() will function as expected, but
* waitq_lock_allow_invalid() will not.
*
* Objects are then initialized and destroyed carefully so that
* this "valid bit" is only set when the object invariants are
* respected.
*
* Returns:
* true: the lock was acquired
* false: the object was freed or not initialized.
*/
bool
ipc_object_lock_allow_invalid(ipc_object_t orig_io)
{
struct waitq *wq = io_waitq(orig_io);
switch (zone_id_for_element(wq, sizeof(*wq))) {
case ZONE_ID_IPC_PORT:
case ZONE_ID_IPC_PORT_SET:
break;
default:
ipc_object_validate_preflight_panic(orig_io);
}
if (__probable(waitq_lock_allow_invalid(wq))) {
ipc_object_t io = io_from_waitq(wq);
ipc_object_validate(io, io_type(io));
return true;
}
return false;
}
__attribute__((always_inline))
void
ipc_object_unlock(ipc_object_t object)
{
release_assert(!object->io_label_lock);
io_unlock_nocheck(object);
}