osfmk/kern/audit_sessionport.c

   1 /*
   2  * Copyright (c) 2008 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 #include <mach/mach_types.h>
  29 #include <mach/notify.h>
  30 #include <ipc/ipc_port.h>
  31 #include <kern/ipc_kobject.h>
  32 #include <kern/audit_sessionport.h>
  33
  34 #if CONFIG_AUDIT
  35 /*
  36  * audit_session_mksend
  37  *
  38  * Description: Obtain a send right for given audit session information.
  39  *
  40  * Parameters:  *aia_p          Audit session information to assosiate with
  41  *                              the new port.
  42  *              *sessionport    Pointer to the current session port.  This may
  43  *                              actually be set to IPC_PORT_NULL.
  44  *
  45  * Returns:     !NULL           Resulting send right.
  46  *              NULL            Failed to allocate port (due to lack of memory
  47  *                              resources).
  48  *
  49  *              *sessionport    The session port that may have been allocated.
  50  *
  51  * Notes: On return, sendport will be set to the new send right on success,
  52  *        or null/dead on error.
  53  */
  54 ipc_port_t
  55 audit_session_mksend(struct auditinfo_addr *aia_p, ipc_port_t *sessionport)
  56 {
  57         ipc_port_t notifyport;
  58         ipc_port_t sendport = IPC_PORT_NULL;
  59
  60         /*
  61          * If we have an existing, active session port then use it.
  62          */
  63         sendport = ipc_port_make_send(*sessionport);
  64         if (IP_VALID(sendport)) {
  65                 ip_lock(sendport);
  66                 if (ip_active(sendport) &&
  67                     IKOT_AU_SESSIONPORT == ip_kotype(sendport)) {
  68                         ip_unlock(sendport);
  69                         return (sendport);
  70                 }
  71                 ip_unlock(sendport);
  72                 ipc_port_release_send(sendport);
  73         }
  74
  75         /*
  76          * Otherwise, create a new one for this session.
  77          */
  78         *sessionport = ipc_port_alloc_kernel();
  79         if (IP_VALID(*sessionport)) {
  80                 ipc_kobject_set(*sessionport, (ipc_kobject_t)aia_p,
  81                     IKOT_AU_SESSIONPORT);
  82
  83                 /* Request a no-senders notification. */
  84                 notifyport = ipc_port_make_sonce(*sessionport);
  85                 ip_lock(*sessionport);
  86                 /* unlocked by ipc_port_nsrequest */
  87                 ipc_port_nsrequest(*sessionport, 1, notifyport, &notifyport);
  88         }
  89         sendport = ipc_port_make_send(*sessionport);
  90
  91         return (sendport);
  92 }
  93
  94
  95 /*
  96  * audit_session_porttoaia
  97  *
  98  * Description: Obtain the audit session info associated with the given port.
  99
 100  * Parameters: port             A Mach port.
 101  *
 102  * Returns:    NULL             The given Mach port did not reference audit
 103  *                              session info.
 104  *             !NULL            The audit session info that is associated with
 105  *                              the Mach port.
 106  *
 107  * Notes: The caller must have a reference on the sessionport.
 108  */
 109 struct auditinfo_addr *
 110 audit_session_porttoaia(ipc_port_t port)
 111 {
 112         struct auditinfo_addr *aia_p = NULL;
 113
 114         if (IP_VALID(port)) {
 115                 ip_lock(port);
 116                 if (ip_active(port) && IKOT_AU_SESSIONPORT == ip_kotype(port))
 117                         aia_p = (struct auditinfo_addr *)port->ip_kobject;
 118                 ip_unlock(port);
 119         }
 120
 121         return (aia_p);
 122 }
 123
 124
 125 /*
 126  * audit_session_nosenders
 127  *
 128  * Description: Handle a no-senders notification for a sessionport.
 129  *
 130  * Parameters: msg              A Mach no-senders notification message.
 131  *
 132  * Notes: It is possible that new send rights are created after a
 133  *        no-senders notification has been sent (i.e. via audit_session_mksend).
 134  *        We check the port's mscount against the notification's not_count
 135  *        to detect when this happens, and re-arm the notification in that
 136  *        case.
 137  *
 138  *        In the normal case (no new senders), we first mark the port
 139  *        as dying by setting its object type to IKOT_NONE so that
 140  *        audit_session_mksend will no longer use it to create
 141  *        additional send rights.  We can then safely call
 142  *        audit_session_port_destroy with no locks.
 143  */
 144 void
 145 audit_session_nosenders(mach_msg_header_t *msg)
 146 {
 147         mach_no_senders_notification_t *notification = (void *)msg;
 148         ipc_port_t port = notification->not_header.msgh_remote_port;
 149         ipc_port_t notifyport;
 150         struct auditinfo_addr *port_aia_p = NULL;
 151
 152         if (!IP_VALID(port))
 153                 return;
 154         ip_lock(port);
 155         if (ip_active(port) && IKOT_AU_SESSIONPORT == ip_kotype(port)) {
 156                 port_aia_p = (struct auditinfo_addr *)port->ip_kobject;
 157                 assert(NULL != port_aia_p);
 158                 if (port->ip_mscount <= notification->not_count)
 159                         ipc_kobject_set_atomically(port, IKO_NULL, IKOT_NONE);
 160                 else {
 161                         /* re-arm the notification */
 162                         ip_unlock(port);
 163                         notifyport = ipc_port_make_sonce(port);
 164                         ip_lock(port);
 165                         /* unlocked by ipc_port_nsrequest */
 166                         ipc_port_nsrequest(port, port->ip_mscount, notifyport,
 167                             &notifyport);
 168                         return;
 169                 }
 170         }
 171         ip_unlock(port);
 172         if (NULL != port_aia_p)
 173                 audit_session_portaiadestroy(port_aia_p);
 174         ipc_port_dealloc_kernel(port);
 175 }
 176 #endif /* CONFIG_AUDIT */