contrib/openbsm/libbsm/bsm_mask.c

   1 /*
   2  * Copyright (c) 2004 Apple Computer, Inc.
   3  * Copyright (c) 2005 Robert N. M. Watson
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1.  Redistributions of source code must retain the above copyright
  10  *     notice, this list of conditions and the following disclaimer.
  11  * 2.  Redistributions in binary form must reproduce the above copyright
  12  *     notice, this list of conditions and the following disclaimer in the
  13  *     documentation and/or other materials provided with the distribution.
  14  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
  15  *     its contributors may be used to endorse or promote products derived
  16  *     from this software without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND
  19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21  * ARE DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR
  22  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  26  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  27  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  28  * POSSIBILITY OF SUCH DAMAGE.
  29  *
  30  * $P4: //depot/projects/trustedbsd/openbsm/libbsm/bsm_mask.c#13 $
  31  */
  32
  33 #include <sys/types.h>
  34
  35 #include <config/config.h>
  36 #ifdef HAVE_FULL_QUEUE_H
  37 #include <sys/queue.h>
  38 #else /* !HAVE_FULL_QUEUE_H */
  39 #include <compat/queue.h>
  40 #endif /* !HAVE_FULL_QUEUE_H */
  41
  42 #include <bsm/libbsm.h>
  43
  44 #include <pthread.h>
  45 #include <stdlib.h>
  46 #include <string.h>
  47
  48 /* MT-Safe */
  49 static pthread_mutex_t  mutex = PTHREAD_MUTEX_INITIALIZER;
  50 static int              firsttime = 1;
  51
  52 /*
  53  * XXX ev_cache, once created, sticks around until the calling program exits.
  54  * This may or may not be a problem as far as absolute memory usage goes, but
  55  * at least there don't appear to be any leaks in using the cache.
  56  *
  57  * XXXRW: Note that despite (mutex), load_event_table() could race with
  58  * other consumers of the getauevents() API.
  59  */
  60 struct audit_event_map {
  61         char                             ev_name[AU_EVENT_NAME_MAX];
  62         char                             ev_desc[AU_EVENT_DESC_MAX];
  63         struct au_event_ent              ev;
  64         LIST_ENTRY(audit_event_map)      ev_list;
  65 };
  66 static LIST_HEAD(, audit_event_map)     ev_cache;
  67
  68 static struct audit_event_map *
  69 audit_event_map_alloc(void)
  70 {
  71         struct audit_event_map *aemp;
  72
  73         aemp = malloc(sizeof(*aemp));
  74         if (aemp == NULL)
  75                 return (aemp);
  76         bzero(aemp, sizeof(*aemp));
  77         aemp->ev.ae_name = aemp->ev_name;
  78         aemp->ev.ae_desc = aemp->ev_desc;
  79         return (aemp);
  80 }
  81
  82 static void
  83 audit_event_map_free(struct audit_event_map *aemp)
  84 {
  85
  86         free(aemp);
  87 }
  88
  89 /*
  90  * When reading into the cache fails, we need to flush the entire cache to
  91  * prevent it from containing some but not all records.
  92  */
  93 static void
  94 flush_cache(void)
  95 {
  96         struct audit_event_map *aemp;
  97
  98         /* XXX: Would assert 'mutex'. */
  99
 100         while ((aemp = LIST_FIRST(&ev_cache)) != NULL) {
 101                 LIST_REMOVE(aemp, ev_list);
 102                 audit_event_map_free(aemp);
 103         }
 104 }
 105
 106 static int
 107 load_event_table(void)
 108 {
 109         struct audit_event_map *aemp;
 110         struct au_event_ent *ep;
 111
 112         /*
 113          * XXX: Would assert 'mutex'.
 114          * Loading of the cache happens only once; dont check if cache is
 115          * already loaded.
 116          */
 117         LIST_INIT(&ev_cache);
 118         setauevent();   /* Rewind to beginning of entries. */
 119         do {
 120                 aemp = audit_event_map_alloc();
 121                 if (aemp == NULL) {
 122                         flush_cache();
 123                         return (-1);
 124                 }
 125                 ep = getauevent_r(&aemp->ev);
 126                 if (ep != NULL)
 127                         LIST_INSERT_HEAD(&ev_cache, aemp, ev_list);
 128                 else
 129                         audit_event_map_free(aemp);
 130         } while (ep != NULL);
 131         return (1);
 132 }
 133
 134 /*
 135  * Read the event with the matching event number from the cache.
 136  */
 137 static struct au_event_ent *
 138 read_from_cache(au_event_t event)
 139 {
 140         struct audit_event_map *elem;
 141
 142         /* XXX: Would assert 'mutex'. */
 143
 144         LIST_FOREACH(elem, &ev_cache, ev_list) {
 145                 if (elem->ev.ae_number == event)
 146                         return (&elem->ev);
 147         }
 148
 149         return (NULL);
 150 }
 151
 152 /*
 153  * Check if the audit event is preselected against the preselection mask.
 154  */
 155 int
 156 au_preselect(au_event_t event, au_mask_t *mask_p, int sorf, int flag)
 157 {
 158         struct au_event_ent *ev;
 159         au_class_t effmask = 0;
 160
 161         if (mask_p == NULL)
 162                 return (-1);
 163
 164
 165         pthread_mutex_lock(&mutex);
 166         if (firsttime) {
 167                 firsttime = 0;
 168                 if ( -1 == load_event_table()) {
 169                         pthread_mutex_unlock(&mutex);
 170                         return (-1);
 171                 }
 172         }
 173         switch (flag) {
 174         case AU_PRS_REREAD:
 175                 flush_cache();
 176                 if (load_event_table() == -1) {
 177                         pthread_mutex_unlock(&mutex);
 178                         return (-1);
 179                 }
 180                 ev = read_from_cache(event);
 181                 break;
 182         case AU_PRS_USECACHE:
 183                 ev = read_from_cache(event);
 184                 break;
 185         default:
 186                 ev = NULL;
 187         }
 188         if (ev == NULL) {
 189                 pthread_mutex_unlock(&mutex);
 190                 return (-1);
 191         }
 192         if (sorf & AU_PRS_SUCCESS)
 193                 effmask |= (mask_p->am_success & ev->ae_class);
 194         if (sorf & AU_PRS_FAILURE)
 195                 effmask |= (mask_p->am_failure & ev->ae_class);
 196         pthread_mutex_unlock(&mutex);
 197         if (effmask != 0)
 198                 return (1);
 199         return (0);
 200 }