/* * Copyright (c) 2008 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@ */ #include <mach/mach_types.h> #include <mach/notify.h> #include <ipc/ipc_port.h> #include <kern/ipc_kobject.h> #include <kern/audit_sessionport.h> #include <libkern/OSAtomic.h> #if CONFIG_AUDIT /* * audit_session_mksend * * Description: Obtain a send right for given audit session. * * Parameters: *aia_p Audit session information to assosiate with * the new port. * *sessionport Pointer to the current session port. This may * actually be set to IPC_PORT_NULL. * * Returns: !NULL Resulting send right. * NULL Failed to allocate port (due to lack of memory * resources). * Assumptions: Caller holds a reference on the session during the call. * If there were no outstanding send rights against the port, * hold a reference on the session and arm a new no-senders * notification to determine when to release that reference. * Otherwise, by creating an additional send right, we share * the port's reference until all send rights go away. */ ipc_port_t audit_session_mksend(struct auditinfo_addr *aia_p, ipc_port_t *sessionport) { ipc_port_t sendport = IPC_PORT_NULL; ipc_port_t port; /* * If we don't have an existing session port, then create one. */ port = *sessionport; if (!IP_VALID(port)) { ipc_port_t new_port = ipc_port_alloc_kernel(); if (!IP_VALID(new_port)) return new_port; ipc_kobject_set(new_port, (ipc_kobject_t)aia_p, IKOT_AU_SESSIONPORT); if (!OSCompareAndSwapPtr(port, new_port, sessionport)) ipc_port_dealloc_kernel(new_port); port = *sessionport; } assert(ip_active(port) && IKOT_AU_SESSIONPORT == ip_kotype(port)); sendport = ipc_port_make_send(port); /* * If we don't have a no-senders notification outstanding against * the port, take a reference on the session and request one. */ if (IP_NULL == port->ip_nsrequest) { ipc_port_t notifyport; audit_session_aiaref(aia_p); ip_lock(port); /* Need a send-once right for the target of the notification */ notifyport = ipc_port_make_sonce_locked(port); /* Request a no-senders notification (at the new make-send threshold) */ ipc_port_nsrequest(port, port->ip_mscount, notifyport, ¬ifyport); /* port unlocked */ if (IP_NULL != notifyport) { /* race requesting notification */ audit_session_aiaunref(aia_p); ipc_port_release_sonce(notifyport); } } return (sendport); } /* * audit_session_porttoaia * * Description: Obtain the audit session info associated with the given port. * Parameters: port A Mach port. * * Returns: NULL The given Mach port did not reference audit * session info. * !NULL The audit session info that is associated with * the Mach port. * * Notes: The caller must have a reference on the sessionport. */ struct auditinfo_addr * audit_session_porttoaia(ipc_port_t port) { struct auditinfo_addr *aia_p = NULL; if (IP_VALID(port)) { ip_lock(port); if (IKOT_AU_SESSIONPORT == ip_kotype(port)) { assert(ip_active(port)); aia_p = (struct auditinfo_addr *)port->ip_kobject; } ip_unlock(port); } return (aia_p); } /* * audit_session_nosenders * * Description: Handle a no-senders notification for a sessionport. * * Parameters: msg A Mach no-senders notification message. * * Notes: It is possible that new send rights are created after a * no-senders notification has been sent (i.e. via audit_session_mksend). * We check the port's mscount against the notification's not_count * to detect when this happens, and re-arm the notification in that * case. * * In the normal case (no new senders), we first mark the port * as dying by setting its object type to IKOT_NONE so that * audit_session_mksend will no longer use it to create * additional send rights. We can then safely call * audit_session_port_destroy with no locks. */ void audit_session_nosenders(mach_msg_header_t *msg) { mach_no_senders_notification_t *notification = (void *)msg; ipc_port_t port = notification->not_header.msgh_remote_port; ipc_port_t notifyport; struct auditinfo_addr *port_aia_p = NULL; assert(IKOT_AU_SESSIONPORT == ip_kotype(port)); ip_lock(port); assert(ip_active(port)); port_aia_p = (struct auditinfo_addr *)port->ip_kobject; assert(NULL != port_aia_p); /* * if new send rights have been made since the last notify * request, re-arm the notification with the new threshold. */ if (port->ip_mscount > notification->not_count) { notifyport = ipc_port_make_sonce_locked(port); ipc_port_nsrequest(port, port->ip_mscount, notifyport, ¬ifyport); /* port unlocked */ if (IP_NULL != notifyport) { /* race re-arming the notification */ ipc_port_release_sonce(notifyport); audit_session_aiaunref(port_aia_p); } return; } /* * Otherwise, no more extant send rights, so release the * reference held on the session by those send rights. */ ip_unlock(port); audit_session_aiaunref(port_aia_p); } void audit_session_portdestroy(ipc_port_t *sessionport) { ipc_port_t port = *sessionport; if (IP_VALID(port)) { assert (ip_active(port)); assert(IKOT_AU_SESSIONPORT == ip_kotype(port)); ipc_kobject_set_atomically(port, IKO_NULL, IKOT_NONE); ipc_port_dealloc_kernel(port); *sessionport = IP_NULL; } } #endif /* CONFIG_AUDIT */