[apple/xnu.git] / osfmk / ipc / mach_msg.c

/*
 * Copyright (c) 2000-2007 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
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * 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 SPARTA, Inc.
 */
/*
 */
/*
 *      File:   ipc/mach_msg.c
 *      Author: Rich Draves
 *      Date:   1989
 *
 *      Exported message traps.  See mach/message.h.
 */

#include <mach/mach_types.h>
#include <mach/kern_return.h>
#include <mach/port.h>
#include <mach/message.h>
#include <mach/mig_errors.h>
#include <mach/mach_traps.h>

#include <kern/kern_types.h>
#include <kern/assert.h>
#include <kern/counters.h>
#include <kern/cpu_number.h>
#include <kern/ipc_kobject.h>
#include <kern/ipc_mig.h>
#include <kern/task.h>
#include <kern/thread.h>
#include <kern/lock.h>
#include <kern/sched_prim.h>
#include <kern/exception.h>
#include <kern/misc_protos.h>
#include <kern/kalloc.h>
#include <kern/processor.h>
#include <kern/syscall_subr.h>

#include <vm/vm_map.h>

#include <ipc/ipc_types.h>
#include <ipc/ipc_kmsg.h>
#include <ipc/ipc_mqueue.h>
#include <ipc/ipc_object.h>
#include <ipc/ipc_notify.h>
#include <ipc/ipc_port.h>
#include <ipc/ipc_pset.h>
#include <ipc/ipc_space.h>
#include <ipc/ipc_entry.h>

#include <machine/machine_routines.h>
#include <security/mac_mach_internal.h>

#include <sys/kdebug.h>

#ifndef offsetof
#define offsetof(type, member)  ((size_t)(&((type *)0)->member))
#endif /* offsetof */

/*
 * Forward declarations - kernel internal routines
 */

mach_msg_return_t mach_msg_send(
        mach_msg_header_t       *msg,
        mach_msg_option_t       option,
        mach_msg_size_t         send_size,
        mach_msg_timeout_t      send_timeout,
        mach_port_name_t        notify);

mach_msg_return_t mach_msg_receive(
        mach_msg_header_t       *msg,
        mach_msg_option_t       option,
        mach_msg_size_t         rcv_size,
        mach_port_name_t        rcv_name,
        mach_msg_timeout_t      rcv_timeout,
        void                    (*continuation)(mach_msg_return_t),
        mach_msg_size_t         slist_size);


mach_msg_return_t msg_receive_error(
        ipc_kmsg_t              kmsg,
        mach_vm_address_t       msg_addr,
        mach_msg_option_t       option,
        mach_port_seqno_t       seqno,
        ipc_space_t             space);

security_token_t KERNEL_SECURITY_TOKEN = KERNEL_SECURITY_TOKEN_VALUE;
audit_token_t KERNEL_AUDIT_TOKEN = KERNEL_AUDIT_TOKEN_VALUE;

mach_msg_format_0_trailer_t trailer_template = {
        /* mach_msg_trailer_type_t */ MACH_MSG_TRAILER_FORMAT_0,
        /* mach_msg_trailer_size_t */ MACH_MSG_TRAILER_MINIMUM_SIZE,
        /* mach_port_seqno_t */       0,
        /* security_token_t */        KERNEL_SECURITY_TOKEN_VALUE
};

/*
 *      Routine:        mach_msg_send [Kernel Internal]
 *      Purpose:
 *              Routine for kernel-task threads to send a message.
 *
 *              Unlike mach_msg_send_from_kernel(), this routine
 *              looks port names up in the kernel's port namespace
 *              and copies in the kernel virtual memory (instead
 *              of taking a vm_map_copy_t pointer for OOL descriptors).
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              MACH_MSG_SUCCESS        Sent the message.
 *              MACH_SEND_MSG_TOO_SMALL Message smaller than a header.
 *              MACH_SEND_NO_BUFFER     Couldn't allocate buffer.
 *              MACH_SEND_INVALID_DATA  Couldn't copy message data.
 *              MACH_SEND_INVALID_HEADER
 *                      Illegal value in the message header bits.
 *              MACH_SEND_INVALID_DEST  The space is dead.
 *              MACH_SEND_INVALID_NOTIFY        Bad notify port.
 *              MACH_SEND_INVALID_DEST  Can't copyin destination port.
 *              MACH_SEND_INVALID_REPLY Can't copyin reply port.
 *              MACH_SEND_TIMED_OUT     Timeout expired without delivery.
 *              MACH_SEND_INTERRUPTED   Delivery interrupted.
 */

mach_msg_return_t
mach_msg_send(
        mach_msg_header_t       *msg,
        mach_msg_option_t       option,
        mach_msg_size_t         send_size,
        mach_msg_timeout_t      send_timeout,
        __unused mach_port_name_t       notify)
{
        ipc_space_t space = current_space();
        vm_map_t map = current_map();
        ipc_kmsg_t kmsg;
        mach_msg_return_t mr;
        mach_msg_size_t msg_and_trailer_size;
        mach_msg_max_trailer_t  *trailer;

        if ((send_size < sizeof(mach_msg_header_t)) || (send_size & 3))
                return MACH_SEND_MSG_TOO_SMALL;

        if (send_size > MACH_MSG_SIZE_MAX - MAX_TRAILER_SIZE)
                return MACH_SEND_TOO_LARGE;
        
        msg_and_trailer_size = send_size + MAX_TRAILER_SIZE;

        kmsg = ipc_kmsg_alloc(msg_and_trailer_size);

        if (kmsg == IKM_NULL)
                return MACH_SEND_NO_BUFFER;

        (void) memcpy((void *) kmsg->ikm_header, (const void *) msg, send_size);

        kmsg->ikm_header->msgh_size = send_size;

        /* 
         * reserve for the trailer the largest space (MAX_TRAILER_SIZE)
         * However, the internal size field of the trailer (msgh_trailer_size)
         * is initialized to the minimum (sizeof(mach_msg_trailer_t)), to optimize
         * the cases where no implicit data is requested.
         */
        trailer = (mach_msg_max_trailer_t *) ((vm_offset_t)kmsg->ikm_header + send_size);
        trailer->msgh_sender = current_thread()->task->sec_token;
        trailer->msgh_audit = current_thread()->task->audit_token;
        trailer->msgh_trailer_type = MACH_MSG_TRAILER_FORMAT_0;
        trailer->msgh_trailer_size = MACH_MSG_TRAILER_MINIMUM_SIZE;

        mr = ipc_kmsg_copyin(kmsg, space, map, &option);

        if (mr != MACH_MSG_SUCCESS) {
                ipc_kmsg_free(kmsg);
                return mr;
        }

        mr = ipc_kmsg_send(kmsg, option, send_timeout);

        if (mr != MACH_MSG_SUCCESS) {
            mr |= ipc_kmsg_copyout_pseudo(kmsg, space, map, MACH_MSG_BODY_NULL);
            (void) memcpy((void *) msg, (const void *) kmsg->ikm_header, 
                          kmsg->ikm_header->msgh_size);
            ipc_kmsg_free(kmsg);
        }

        return mr;
}

/* 
 * message header as seen at user-space
 * (for MACH_RCV_LARGE/IDENTITY updating)
 */
typedef struct 
{
  mach_msg_bits_t       msgh_bits;
  mach_msg_size_t       msgh_size;
  mach_port_name_t      msgh_remote_port;
  mach_port_name_t      msgh_local_port;
  mach_msg_size_t       msgh_reserved;
  mach_msg_id_t         msgh_id;
} mach_msg_user_header_t;

/*
 *      Routine:        mach_msg_receive_results
 *      Purpose:
 *              Receive a message.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              MACH_MSG_SUCCESS        Received a message.
 *              MACH_RCV_INVALID_NAME   The name doesn't denote a right,
 *                      or the denoted right is not receive or port set.
 *              MACH_RCV_IN_SET         Receive right is a member of a set.
 *              MACH_RCV_TOO_LARGE      Message wouldn't fit into buffer.
 *              MACH_RCV_TIMED_OUT      Timeout expired without a message.
 *              MACH_RCV_INTERRUPTED    Reception interrupted.
 *              MACH_RCV_PORT_DIED      Port/set died while receiving.
 *              MACH_RCV_PORT_CHANGED   Port moved into set while receiving.
 *              MACH_RCV_INVALID_DATA   Couldn't copy to user buffer.
 *              MACH_RCV_INVALID_NOTIFY Bad notify port.
 *              MACH_RCV_HEADER_ERROR
 */

mach_msg_return_t
mach_msg_receive_results(void)
{
        thread_t          self = current_thread();
        ipc_space_t       space = current_space();
        vm_map_t          map = current_map();

        ipc_object_t      object = self->ith_object;
        mach_msg_return_t mr = self->ith_state;
        mach_vm_address_t msg_addr = self->ith_msg_addr;
        mach_msg_option_t option = self->ith_option;
        ipc_kmsg_t        kmsg = self->ith_kmsg;
        mach_port_seqno_t seqno = self->ith_seqno;
        mach_msg_trailer_size_t trailer_size;

        io_release(object);

        if (mr != MACH_MSG_SUCCESS) {

          if (mr == MACH_RCV_TOO_LARGE ) {
            if (option & MACH_RCV_LARGE) {
              /*
               * We need to inform the user-level code that it needs more
               * space.  The value for how much space was returned in the
               * msize save area instead of the message (which was left on
               * the queue).
               */
              if (option & MACH_RCV_LARGE_IDENTITY) {
                      if (copyout((char *) &self->ith_receiver_name,
                                  msg_addr + offsetof(mach_msg_user_header_t, msgh_local_port),
                                  sizeof(mach_port_name_t)))
                              mr = MACH_RCV_INVALID_DATA;
              }
              if (copyout((char *) &self->ith_msize,
                          msg_addr + offsetof(mach_msg_user_header_t, msgh_size),
                          sizeof(mach_msg_size_t)))
                mr = MACH_RCV_INVALID_DATA;
              goto out;
            }
                  
            if (msg_receive_error(kmsg, msg_addr, option, seqno, space)
                == MACH_RCV_INVALID_DATA)
              mr = MACH_RCV_INVALID_DATA;
          }
          goto out;
        }

#if IMPORTANCE_INHERITANCE
        if ((kmsg->ikm_header->msgh_bits & MACH_MSGH_BITS_RAISEIMP) != 0) {
                __unused int impresult;
                int sender_pid = -1;
#if IMPORTANCE_DEBUG
                sender_pid = ((mach_msg_max_trailer_t *)
                        ((vm_offset_t)kmsg->ikm_header + round_msg(kmsg->ikm_header->msgh_size)))->msgh_audit.val[5];
#endif /* IMPORTANCE_DEBUG */
                ipc_port_t port = kmsg->ikm_header->msgh_remote_port;
                task_t task_self = current_task();

                ip_lock(port);
                assert(port->ip_impcount > 0);
                port->ip_impcount--;
                ip_unlock(port);

                if (task_self->imp_receiver == 0) {
                        /*
                         * The task was never ready to receive importance boost, remove msghbit.
                         * This can happen when a receive right (which has donor messages) is copied
                         * out to a non-imp_receiver task (we don't clear the bits on the messages,
                         * but we did't transfer any boost counts either).
                         */
                        kmsg->ikm_header->msgh_bits &= ~MACH_MSGH_BITS_RAISEIMP;
                        impresult = 0;
                } else {
                        /* user will accept responsibility for the importance boost */
                        task_importance_externalize_assertion(task_self, 1, sender_pid);
                        impresult = 1;
                }

#if IMPORTANCE_DEBUG
                KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE, (IMPORTANCE_CODE(IMP_MSG, IMP_MSG_DELV)) | DBG_FUNC_NONE,
                        sender_pid, audit_token_pid_from_task(task_self),
                        kmsg->ikm_header->msgh_id, impresult, 0);
#endif /* IMPORTANCE_DEBUG */
        }
#endif  /* IMPORTANCE_INHERITANCE */

        trailer_size = ipc_kmsg_add_trailer(kmsg, space, option, self, seqno, FALSE, 
                        kmsg->ikm_header->msgh_remote_port->ip_context);
        /*
         * If MACH_RCV_OVERWRITE was specified, try to get the scatter
         * list and verify it against the contents of the message.  If
         * there is any problem with it, we will continue without it as
         * normal.
         */
        if (option & MACH_RCV_OVERWRITE) {
                mach_msg_size_t slist_size = self->ith_scatter_list_size;
                mach_msg_body_t *slist;

                slist = ipc_kmsg_get_scatter(msg_addr, slist_size, kmsg);
                mr = ipc_kmsg_copyout(kmsg, space, map, slist);
                ipc_kmsg_free_scatter(slist, slist_size);
        } else {
                mr = ipc_kmsg_copyout(kmsg, space, map, MACH_MSG_BODY_NULL);
        }

        if (mr != MACH_MSG_SUCCESS) {
                if ((mr &~ MACH_MSG_MASK) == MACH_RCV_BODY_ERROR) {
                        if (ipc_kmsg_put(msg_addr, kmsg, kmsg->ikm_header->msgh_size +
                           trailer_size) == MACH_RCV_INVALID_DATA)
                                mr = MACH_RCV_INVALID_DATA;
                } 
                else {
                        if (msg_receive_error(kmsg, msg_addr, option, seqno, space) 
                                                == MACH_RCV_INVALID_DATA)
                                mr = MACH_RCV_INVALID_DATA;
                }
                goto out;
        }
        mr = ipc_kmsg_put(msg_addr,
                          kmsg,
                          kmsg->ikm_header->msgh_size + 
                          trailer_size);
 out:
        return mr;
}

/*
 *      Routine:        mach_msg_receive [Kernel Internal]
 *      Purpose:
 *              Routine for kernel-task threads to actively receive a message.
 *
 *              Unlike being dispatched to by ipc_kobject_server() or the
 *              reply part of mach_msg_rpc_from_kernel(), this routine
 *              looks up the receive port name in the kernel's port
 *              namespace and copies out received port rights to that namespace
 *              as well.  Out-of-line memory is copied out the kernel's
 *              address space (rather than just providing the vm_map_copy_t).
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              MACH_MSG_SUCCESS        Received a message.
 *              See <mach/message.h> for list of MACH_RCV_XXX errors.
 */
mach_msg_return_t
mach_msg_receive(
        mach_msg_header_t       *msg,
        mach_msg_option_t       option,
        mach_msg_size_t         rcv_size,
        mach_port_name_t        rcv_name,
        mach_msg_timeout_t      rcv_timeout,
        void                    (*continuation)(mach_msg_return_t),
        mach_msg_size_t         slist_size)
{
        thread_t self = current_thread();
        ipc_space_t space = current_space();
        ipc_object_t object;
        ipc_mqueue_t mqueue;
        mach_msg_return_t mr;

        mr = ipc_mqueue_copyin(space, rcv_name, &mqueue, &object);
        if (mr != MACH_MSG_SUCCESS) {
                return mr;
        }
        /* hold ref for object */

        self->ith_msg_addr = CAST_DOWN(mach_vm_address_t, msg);
        self->ith_object = object;
        self->ith_msize = rcv_size;
        self->ith_option = option;
        self->ith_scatter_list_size = slist_size;
        self->ith_continuation = continuation;

        ipc_mqueue_receive(mqueue, option, rcv_size, rcv_timeout, THREAD_ABORTSAFE);
        if ((option & MACH_RCV_TIMEOUT) && rcv_timeout == 0)
                thread_poll_yield(self);
        return mach_msg_receive_results();
}

void
mach_msg_receive_continue(void)
{
        thread_t self = current_thread();

        (*self->ith_continuation)(mach_msg_receive_results());
}


/*
 *      Routine:        mach_msg_overwrite_trap [mach trap]
 *      Purpose:
 *              Possibly send a message; possibly receive a message.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              All of mach_msg_send and mach_msg_receive error codes.
 */

mach_msg_return_t
mach_msg_overwrite_trap(
        struct mach_msg_overwrite_trap_args *args)
{
        mach_vm_address_t       msg_addr = args->msg;
        mach_msg_option_t       option = args->option;
        mach_msg_size_t         send_size = args->send_size;
        mach_msg_size_t         rcv_size = args->rcv_size;
        mach_port_name_t        rcv_name = args->rcv_name;
        mach_msg_timeout_t      msg_timeout = args->timeout;
        __unused mach_port_name_t notify = args->notify;
        mach_vm_address_t       rcv_msg_addr = args->rcv_msg;
        mach_msg_size_t         scatter_list_size = 0; /* NOT INITIALIZED - but not used in pactice */
        __unused mach_port_seqno_t temp_seqno = 0;

        mach_msg_return_t  mr = MACH_MSG_SUCCESS;
        vm_map_t map = current_map();

        /* Only accept options allowed by the user */
        option &= MACH_MSG_OPTION_USER;

        if (option & MACH_SEND_MSG) {
                ipc_space_t space = current_space();
                ipc_kmsg_t kmsg;

                mr = ipc_kmsg_get(msg_addr, send_size, &kmsg);

                if (mr != MACH_MSG_SUCCESS)
                        return mr;

                mr = ipc_kmsg_copyin(kmsg, space, map, &option);

                if (mr != MACH_MSG_SUCCESS) {
                        ipc_kmsg_free(kmsg);
                        return mr;
                }

                mr = ipc_kmsg_send(kmsg, option, msg_timeout);

                if (mr != MACH_MSG_SUCCESS) {
                        mr |= ipc_kmsg_copyout_pseudo(kmsg, space, map, MACH_MSG_BODY_NULL);
                        (void) ipc_kmsg_put(msg_addr, kmsg, kmsg->ikm_header->msgh_size);
                        return mr;
                }

        }

        if (option & MACH_RCV_MSG) {
                thread_t self = current_thread();
                ipc_space_t space = current_space();
                ipc_object_t object;
                ipc_mqueue_t mqueue;

                mr = ipc_mqueue_copyin(space, rcv_name, &mqueue, &object);
                if (mr != MACH_MSG_SUCCESS) {
                        return mr;
                }
                /* hold ref for object */

                /*
                 * 1. MACH_RCV_OVERWRITE is on, and rcv_msg is our scatter list
                 *    and receive buffer
                 * 2. MACH_RCV_OVERWRITE is off, and rcv_msg might be the
                 *    alternate receive buffer (separate send and receive buffers).
                 */
                if (option & MACH_RCV_OVERWRITE) 
                        self->ith_msg_addr = rcv_msg_addr;
                else if (rcv_msg_addr != (mach_vm_address_t)0)
                        self->ith_msg_addr = rcv_msg_addr;
                else
                        self->ith_msg_addr = msg_addr;
                self->ith_object = object;
                self->ith_msize = rcv_size;
                self->ith_option = option;
                self->ith_scatter_list_size = scatter_list_size;
                self->ith_receiver_name = MACH_PORT_NULL;
                self->ith_continuation = thread_syscall_return;

                ipc_mqueue_receive(mqueue, option, rcv_size, msg_timeout, THREAD_ABORTSAFE);
                if ((option & MACH_RCV_TIMEOUT) && msg_timeout == 0)
                        thread_poll_yield(self);
                return mach_msg_receive_results();
        }

        return MACH_MSG_SUCCESS;
}

/*
 *      Routine:        mach_msg_trap [mach trap]
 *      Purpose:
 *              Possibly send a message; possibly receive a message.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              All of mach_msg_send and mach_msg_receive error codes.
 */

mach_msg_return_t
mach_msg_trap(
        struct mach_msg_overwrite_trap_args *args)
{
        kern_return_t kr;
        args->rcv_msg = (mach_vm_address_t)0;

        kr = mach_msg_overwrite_trap(args);
        return kr;
}
 

/*
 *      Routine:        msg_receive_error       [internal]
 *      Purpose:
 *              Builds a minimal header/trailer and copies it to
 *              the user message buffer.  Invoked when in the case of a
 *              MACH_RCV_TOO_LARGE or MACH_RCV_BODY_ERROR error.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              MACH_MSG_SUCCESS        minimal header/trailer copied
 *              MACH_RCV_INVALID_DATA   copyout to user buffer failed
 */
        
mach_msg_return_t
msg_receive_error(
        ipc_kmsg_t              kmsg,
        mach_vm_address_t       msg_addr,
        mach_msg_option_t       option,
        mach_port_seqno_t       seqno,
        ipc_space_t             space)
{
        mach_vm_address_t       context;
        mach_msg_trailer_size_t trailer_size;
        mach_msg_max_trailer_t  *trailer;

        context = kmsg->ikm_header->msgh_remote_port->ip_context;

        /*
         * Copy out the destination port in the message.
         * Destroy all other rights and memory in the message.
         */
        ipc_kmsg_copyout_dest(kmsg, space);

        /*
         * Build a minimal message with the requested trailer.
         */
        trailer = (mach_msg_max_trailer_t *) 
                        ((vm_offset_t)kmsg->ikm_header +
                        round_msg(sizeof(mach_msg_header_t)));
        kmsg->ikm_header->msgh_size = sizeof(mach_msg_header_t);
        bcopy(  (char *)&trailer_template, 
                (char *)trailer, 
                sizeof(trailer_template));

        trailer_size = ipc_kmsg_add_trailer(kmsg, space, 
                        option, current_thread(), seqno,
                        TRUE, context);

        /*
         * Copy the message to user space
         */
        if (ipc_kmsg_put(msg_addr, kmsg, kmsg->ikm_header->msgh_size +
                        trailer_size) == MACH_RCV_INVALID_DATA)
                return(MACH_RCV_INVALID_DATA);
        else 
                return(MACH_MSG_SUCCESS);
}