aboutsummaryrefslogtreecommitdiffstats
path: root/libauditd/auditd_lib.c
blob: bf57155cd8ef41ee0007545ca0eb369368d1ad8d (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
/*-
 * Copyright (c) 2008-2009 Apple Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 * 3.  Neither the name of Apple Inc. ("Apple") nor the names of
 *     its contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * $P4: //depot/projects/trustedbsd/openbsm/libauditd/auditd_lib.c#11 $
 */

#include <sys/param.h>

#include <config/config.h>

#include <sys/dirent.h>
#ifdef HAVE_FULL_QUEUE_H
#include <sys/queue.h>
#else /* !HAVE_FULL_QUEUE_H */
#include <compat/queue.h>
#endif /* !HAVE_FULL_QUEUE_H */
#include <sys/mount.h>
#include <sys/socket.h>

#include <sys/stat.h>
#include <sys/time.h>

#include <netinet/in.h>

#include <bsm/audit.h>
#include <bsm/audit_uevents.h>
#include <bsm/auditd_lib.h>
#include <bsm/libbsm.h>

#include <dirent.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
#include <netdb.h>

#ifdef __APPLE__
#include <notify.h>
#ifndef __BSM_INTERNAL_NOTIFY_KEY
#define __BSM_INTERNAL_NOTIFY_KEY "com.apple.audit.change"
#endif /* __BSM_INTERNAL_NOTIFY_KEY */
#endif /* __APPLE__ */

/*
 * XXX This is temporary until this is moved to <bsm/audit.h> and shared with
 * the kernel.
 */
#ifndef	AUDIT_HARD_LIMIT_FREE_BLOCKS
#define	AUDIT_HARD_LIMIT_FREE_BLOCKS	4
#endif

/*
 * Number of seconds to January 1, 2000
 */
#define	JAN_01_2000	946598400

struct dir_ent {
	char			*dirname;
	uint8_t			 softlim;
	uint8_t			 hardlim;
	TAILQ_ENTRY(dir_ent)	 dirs;
};

static TAILQ_HEAD(, dir_ent)	dir_q;

struct audit_trail {
	time_t			 at_time;
	char			*at_path;
	off_t			 at_size;

	TAILQ_ENTRY(audit_trail) at_trls;
};

static int auditd_minval = -1;

static char auditd_host[MAXHOSTNAMELEN];
static int auditd_hostlen = -1;

static char *auditd_errmsg[] = {
	"no error",					/* ADE_NOERR 	( 0) */
	"could not parse audit_control(5) file",	/* ADE_PARSE 	( 1) */
	"auditon(2) failed",				/* ADE_AUDITON 	( 2) */
	"malloc(3) failed",				/* ADE_NOMEM 	( 3) */
	"all audit log directories over soft limit",	/* ADE_SOFTLIM  ( 4) */
	"all audit log directories over hard limit",	/* ADE_HARDLIM 	( 5) */
	"could not create file name string",		/* ADE_STRERR 	( 6) */
	"could not open audit record", 			/* ADE_AU_OPEN 	( 7) */
	"could not close audit record",			/* ADE_AU_CLOSE ( 8) */
	"could not set active audit session state",	/* ADE_SETAUDIT ( 9) */
	"auditctl(2) failed (trail still swapped)",	/* ADE_ACTL 	(10) */
	"auditctl(2) failed (trail not swapped)",	/* ADE_ACTLERR  (11) */
	"could not swap audit trail file",		/* ADE_SWAPERR 	(12) */
	"could not rename crash recovery file",		/* ADE_RENAME	(13) */
	"could not read 'current' link file",		/* ADE_READLINK	(14) */
	"could not create 'current' link file", 	/* ADE_SYMLINK  (15) */
	"invalid argument",				/* ADE_INVAL	(16) */
	"could not resolve hostname to address",	/* ADE_GETADDR	(17) */
	"address family not supported",			/* ADE_ADDRFAM	(18) */
	"error expiring audit trail files",		/* ADE_EXPIRE	(19) */
};

#define MAXERRCODE (sizeof(auditd_errmsg) / sizeof(auditd_errmsg[0]))

#define NA_EVENT_STR_SIZE       128
#define POL_STR_SIZE            128


/*
 * Look up and return the error string for the given audit error code.
 */
const char *
auditd_strerror(int errcode)
{
	int idx = -errcode;

	if (idx < 0 || idx > (int)MAXERRCODE)
		return ("Invalid auditd error code");
	
	return (auditd_errmsg[idx]);
}


/*
 * Free our local list of directory names and init list 
 */
static void
free_dir_q(void)
{
	struct dir_ent *d1, *d2;
	
	d1 = TAILQ_FIRST(&dir_q);
	while (d1 != NULL) {
		d2 = TAILQ_NEXT(d1, dirs);
		free(d1->dirname);
		free(d1);
		d1 = d2;
	}
	TAILQ_INIT(&dir_q);
}

/*
 * Concat the directory name to the given file name.
 * XXX We should affix the hostname also
 */
static char *
affixdir(char *name, struct dir_ent *dirent)
{
	char *fn = NULL;

	/*
	 * Sanity check on file name.
	 */
	if (strlen(name) != (FILENAME_LEN - 1)) {
		errno = EINVAL;
                return (NULL);
	}

	/*
	 * If the host is set then also add the hostname to the filename.
	 */
	if (auditd_hostlen != -1)
		asprintf(&fn, "%s/%s.%s", dirent->dirname, name, auditd_host);
	else
		asprintf(&fn, "%s/%s", dirent->dirname, name);
	return (fn);
}

/*
 * Insert the directory entry in the list by the way they are ordered in
 * audit_control(5).  Move the entries that are over the soft and hard limits
 * toward the tail.
 */
static void
insert_orderly(struct dir_ent *denew)
{
	struct dir_ent *dep;
	
	TAILQ_FOREACH(dep, &dir_q, dirs) {
		if (dep->softlim == 1 && denew->softlim == 0) {
			TAILQ_INSERT_BEFORE(dep, denew, dirs);
			return;			
		}
		if (dep->hardlim == 1 && denew->hardlim == 0) {
			TAILQ_INSERT_BEFORE(dep, denew, dirs);
			return;
		}
	}
	TAILQ_INSERT_TAIL(&dir_q, denew, dirs);
}

/*
 * Get the host from audit_control(5) and set it in the audit kernel
 * information.  Return:
 *	ADE_NOERR	on success.
 *	ADE_PARSE	error parsing audit_control(5).
 *	ADE_AUDITON	error getting/setting auditon(2) value.
 *	ADE_GETADDR 	error getting address info for host. 
 *	ADE_ADDRFAM	un-supported address family. 	
 */
int
auditd_set_host(void)
{
	struct sockaddr_in6 *sin6;
	struct sockaddr_in *sin;
	struct addrinfo *res;
	struct auditinfo_addr aia;
	int error, ret = ADE_NOERR;

	if (getachost(auditd_host, sizeof(auditd_host)) != 0) {
		ret = ADE_PARSE;	
	
		/*
		 * To maintain reverse compatability with older audit_control
		 * files, simply drop a warning if the host parameter has not
		 * been set.  However, we will explicitly disable the
		 * generation of extended audit header by passing in a zeroed
		 * termid structure.
		 */
		bzero(&aia, sizeof(aia));
		aia.ai_termid.at_type = AU_IPv4;
		error = audit_set_kaudit(&aia, sizeof(aia));
		if (error < 0 && errno != ENOSYS)
			ret = ADE_AUDITON;
		return (ret);
	}
	auditd_hostlen = strlen(auditd_host);
	error = getaddrinfo(auditd_host, NULL, NULL, &res);
	if (error)
		return (ADE_GETADDR);
	switch (res->ai_family) {
	case PF_INET6:
		sin6 = (struct sockaddr_in6 *) res->ai_addr;
		bcopy(&sin6->sin6_addr.s6_addr,
		    &aia.ai_termid.at_addr[0], sizeof(struct in6_addr));
		aia.ai_termid.at_type = AU_IPv6;
		break;

	case PF_INET:
		sin = (struct sockaddr_in *) res->ai_addr;
		bcopy(&sin->sin_addr.s_addr,
		    &aia.ai_termid.at_addr[0], sizeof(struct in_addr));
		aia.ai_termid.at_type = AU_IPv4;
		break;

	default:
		/* Un-supported address family in host parameter. */
		errno = EAFNOSUPPORT;
		return (ADE_ADDRFAM);
	}

	if (audit_set_kaudit(&aia, sizeof(aia)) < 0)
		ret = ADE_AUDITON;

	return (ret);
}

/* 
 * Get the min percentage of free blocks from audit_control(5) and that
 * value in the kernel.  Return:
 *	ADE_NOERR	on success,
 *	ADE_PARSE 	error parsing audit_control(5),
 *	ADE_AUDITON	error getting/setting auditon(2) value.
 */
int
auditd_set_minfree(void)
{
	au_qctrl_t qctrl;

	if (getacmin(&auditd_minval) != 0)
		return (ADE_PARSE);
	
	if (audit_get_qctrl(&qctrl, sizeof(qctrl)) != 0)
		return (ADE_AUDITON);

	if (qctrl.aq_minfree != auditd_minval) {
		qctrl.aq_minfree = auditd_minval;
		if (audit_set_qctrl(&qctrl, sizeof(qctrl)) != 0)
			return (ADE_AUDITON);
	}

	return (0);
}

/*
 * Convert a trailname into a timestamp (seconds).  Return 0 if the conversion
 * was successful.
 */
static int
trailname_to_tstamp(char *fn, time_t *tstamp)
{
	struct tm tm;
	char ts[TIMESTAMP_LEN];
	char *p;

	*tstamp = 0;

	/*
	 * Get the ending time stamp.
	 */
	if ((p = strchr(fn, '.')) == NULL)
		return (1);
	strlcpy(ts, ++p, TIMESTAMP_LEN);
	if (strlen(ts) != POSTFIX_LEN)
		return (1);

	bzero(&tm, sizeof(tm));

	/* seconds (0-60) */
	p = ts + POSTFIX_LEN - 2;
	tm.tm_sec = atol(p);
	if (tm.tm_sec < 0 || tm.tm_sec > 60)
		return (1);

	/* minutes (0-59) */ 
	*p = '\0'; p -= 2;
	tm.tm_min = atol(p);
	if (tm.tm_min < 0 || tm.tm_min > 59)
		return (1);

	/* hours (0 - 23) */
	*p = '\0'; p -= 2;
	tm.tm_hour = atol(p);
	if (tm.tm_hour < 0 || tm.tm_hour > 23)
		return (1);

	/* day of month (1-31) */
	*p = '\0'; p -= 2;
	tm.tm_mday = atol(p);
	if (tm.tm_mday < 1 || tm.tm_mday > 31)
		return (1);

	/* month (0 - 11) */
	*p = '\0'; p -= 2;
	tm.tm_mon = atol(p) - 1;
	if (tm.tm_mon < 0 || tm.tm_mon > 11)
		return (1);

	/* year (year - 1900) */
	*p = '\0'; p -= 4;
	tm.tm_year = atol(p) - 1900;
	if (tm.tm_year < 0)
		return (1);

	*tstamp = timegm(&tm);

	return (0);
}

/*
 * Remove audit trails files according to the expiration conditions.  Returns:
 * 	ADE_NOERR	on success or there is nothing to do.
 * 	ADE_PARSE	if error parsing audit_control(5).
 * 	ADE_NOMEM	if could not allocate memory.
 * 	ADE_EXPIRE	if there was an unespected error.
 */
int
auditd_expire_trails(int (*warn_expired)(char *))
{
	int andflg, ret = ADE_NOERR;
	size_t expire_size, total_size = 0L;
	time_t expire_age, oldest_time, current_time = time(NULL);
	struct dir_ent *traildir;
	struct audit_trail *at;
	char *afnp, *pn;
	TAILQ_HEAD(au_trls_head, audit_trail) head =
	    TAILQ_HEAD_INITIALIZER(head);
	struct stat stbuf;
	char activefn[MAXPATHLEN];

	/*
	 * Read the expiration conditions.  If no conditions then return no
	 * error.
	 */
	if (getacexpire(&andflg, &expire_age, &expire_size) < 0)
		return (ADE_PARSE);
	if (!expire_age && !expire_size)
		return (ADE_NOERR);

	/*
	 * Read the 'current' trail file name.  Trim off directory path.
	 */
	activefn[0] = '\0';
	readlink(AUDIT_CURRENT_LINK, activefn, MAXPATHLEN - 1);
	if ((afnp = strrchr(activefn, '/')) != NULL) 
		afnp++;


	/*
	 * Build tail queue of the trail files.
	 */
	TAILQ_FOREACH(traildir, &dir_q, dirs) {
		DIR *dirp;
		struct dirent *dp;

		dirp = opendir(traildir->dirname);
		while ((dp = readdir(dirp)) != NULL) {
			time_t tstamp = 0;
			struct audit_trail *new;

			/*
			 * Quickly filter non-trail files.
			 */
			if (dp->d_namlen != (FILENAME_LEN - 1) ||
#ifdef DT_REG
			    dp->d_type != DT_REG || 
#endif
			    dp->d_name[POSTFIX_LEN] != '.')
				continue;

			if (asprintf(&pn, "%s/%s", traildir->dirname,
				dp->d_name) < 0) {
				ret = ADE_NOMEM;
				break;
			}

			if (stat(pn, &stbuf) < 0 || !S_ISREG(stbuf.st_mode)) {
				free(pn);
				continue;
			}

			total_size += stbuf.st_size;

			/*
			 * If this is the 'current' audit trail then
			 * don't add it to the tail queue.
			 */
			if (NULL != afnp &&
			    strncmp(dp->d_name, afnp, FILENAME_LEN) == 0) {
				free(pn);
				continue;
			}

			/*
			 * Get the ending time stamp encoded in the trail
			 * name.  If we can't read it or if it is older
			 * than Jan 1, 2000 then use the mtime.
			 */
			if (trailname_to_tstamp(dp->d_name, &tstamp) != 0 ||
			    tstamp < JAN_01_2000)
				tstamp = stbuf.st_mtime;

			/*
			 * If the time stamp is older than Jan 1, 2000 then
			 * update the mtime of the trail file to the current
			 * time. This is so we don't prematurely remove a trail
			 * file that was created while the system clock reset
			 * to the * "beginning of time" but later the system
			 * clock is set to the correct current time.
			 */
			if (current_time >= JAN_01_2000 &&
			    tstamp < JAN_01_2000) {
				struct timeval tv[2];

				tstamp = stbuf.st_mtime = current_time;
				TIMESPEC_TO_TIMEVAL(&tv[0], 
				    &stbuf.st_atimespec);
				TIMESPEC_TO_TIMEVAL(&tv[1], 
				    &stbuf.st_mtimespec);
				utimes(pn, tv);
			}

			/*
			 * Allocate and populate the new entry.
			 */
			new = malloc(sizeof(*new));
			if (NULL == new) {
				free(pn);
				ret = ADE_NOMEM;
				break;
			}
			new->at_time = tstamp;
			new->at_size = stbuf.st_size;
			new->at_path = pn;

			/*
			 * Check to see if we have a new head.  Otherwise,
			 * walk the tailq from the tail first and do a simple
			 * insertion sort.
			 */
			if (TAILQ_EMPTY(&head) ||
			    (new->at_time <= TAILQ_FIRST(&head)->at_time)) {
				TAILQ_INSERT_HEAD(&head, new, at_trls);
				continue;
			}

			TAILQ_FOREACH_REVERSE(at, &head, au_trls_head, at_trls)
				if (new->at_time >= at->at_time) {
					TAILQ_INSERT_AFTER(&head, at, new,
					    at_trls);
					break;
				}

		}
	}

	oldest_time = current_time - expire_age;

	/* 
	 * Expire trail files, oldest (mtime) first, if the given
	 * conditions are met.
	 */
	at = TAILQ_FIRST(&head);
	while (NULL != at) {
		struct audit_trail *at_next = TAILQ_NEXT(at, at_trls);

		if (andflg) {
			if ((expire_size && total_size > expire_size) &&
			    (expire_age && at->at_time < oldest_time)) {
				if (warn_expired)
				    (*warn_expired)(at->at_path);
				if (unlink(at->at_path) < 0)
					ret = ADE_EXPIRE;
				total_size -= at->at_size;
			}
		} else {
			if ((expire_size && total_size > expire_size) ||
			    (expire_age && at->at_time < oldest_time)) {
				if (warn_expired)
				    (*warn_expired)(at->at_path);
				if (unlink(at->at_path) < 0)
					ret = ADE_EXPIRE;
				total_size -= at->at_size;
			}
		}

		free(at->at_path);
		free(at);
		at = at_next;
	}

	return (ret);
}

/*
 * Parses the "dir" entry in audit_control(5) into an ordered list.  Also, will
 * set the minfree and host values if not already set.  Arguments include
 * function pointers to audit_warn functions for soft and hard limits. Returns:
 *	ADE_NOERR	on success,
 *	ADE_PARSE	error parsing audit_control(5),
 *	ADE_AUDITON	error getting/setting auditon(2) value,
 *	ADE_NOMEM	error allocating memory,
 *	ADE_SOFTLIM	if all the directories are over the soft limit,
 *	ADE_HARDLIM	if all the directories are over the hard limit,
 */
int
auditd_read_dirs(int (*warn_soft)(char *), int (*warn_hard)(char *))
{
	char cur_dir[MAXNAMLEN];
	struct dir_ent *dirent;
	struct statfs sfs;
	int err;
	char soft, hard;
	int tcnt = 0;
	int scnt = 0;
	int hcnt = 0;

	if (auditd_minval == -1 && (err = auditd_set_minfree()) != 0)
		return (err);

	if (auditd_hostlen == -1)
		auditd_set_host();

        /*
         * Init directory q.  Force a re-read of the file the next time.
         */
	free_dir_q();
	endac();

	/*
	 * Read the list of directories into an ordered linked list
	 * admin's preference, then those over soft limit and, finally,
	 * those over the hard limit.
	 *
         * XXX We should use the reentrant interfaces once they are
         * available.
         */
	while (getacdir(cur_dir, MAXNAMLEN) >= 0) {
		if (statfs(cur_dir, &sfs) < 0)
			continue;  /* XXX should warn */
		soft = (sfs.f_bfree < (sfs.f_blocks / (100 / auditd_minval))) ?
		    1 : 0;
		hard = (sfs.f_bfree < AUDIT_HARD_LIMIT_FREE_BLOCKS) ? 1 : 0;
		if (soft) {
			if (warn_soft) 
				(*warn_soft)(cur_dir);
			scnt++;
		}
		if (hard) {
			if (warn_hard)
				(*warn_hard)(cur_dir);
			hcnt++;
		}
		dirent = (struct dir_ent *) malloc(sizeof(struct dir_ent));
		if (dirent == NULL)
			return (ADE_NOMEM);
		dirent->softlim = soft;
		dirent->hardlim = hard; 
		dirent->dirname = (char *) malloc(MAXNAMLEN);
		if (dirent->dirname == NULL) {
			free(dirent);
			return (ADE_NOMEM);
		}
		strlcpy(dirent->dirname, cur_dir, MAXNAMLEN);
		insert_orderly(dirent);
		tcnt++;
	}

	if (hcnt == tcnt)
		return (ADE_HARDLIM);
	if (scnt == tcnt)
		return (ADE_SOFTLIM);
	return (0);
}

void
auditd_close_dirs(void)
{
	free_dir_q();
	auditd_minval = -1;
	auditd_hostlen = -1;
}


/*
 * Process the audit event file, obtaining a class mapping for each event, and
 * set that mapping into the kernel. Return:
 * 	 n	number of event mappings that were successfully processed,
 *   ADE_NOMEM	if there was an error allocating memory.	
 */
int
auditd_set_evcmap(void)
{
	au_event_ent_t ev, *evp;
	au_evclass_map_t evc_map;
	int ctr = 0;

         
	/*
	 * XXX There's a risk here that the BSM library will return NULL
	 * for an event when it can't properly map it to a class. In that
	 * case, we will not process any events beyond the one that failed,
	 * but should. We need a way to get a count of the events.
	 */
	ev.ae_name = (char *)malloc(AU_EVENT_NAME_MAX);
	ev.ae_desc = (char *)malloc(AU_EVENT_DESC_MAX);
	if ((ev.ae_name == NULL) || (ev.ae_desc == NULL)) {
		if (ev.ae_name != NULL)
			free(ev.ae_name);
		return (ADE_NOMEM);
	}
                 
	/*
	 * XXXRW: Currently we have no way to remove mappings from the kernel
	 * when they are removed from the file-based mappings.
	 */
	evp = &ev;
	setauevent();
	while ((evp = getauevent_r(evp)) != NULL) {
		evc_map.ec_number = evp->ae_number;
		evc_map.ec_class = evp->ae_class;
		if (audit_set_class(&evc_map, sizeof(evc_map)) == 0)
			ctr++;
	}
	endauevent();
	free(ev.ae_name);
	free(ev.ae_desc);

	return (ctr);
}

/*
 * Get the non-attributable event string and set the kernel mask.  Return:
 *	ADE_NOERR 	on success,
 *	ADE_PARSE	error parsing audit_control(5),
 *	ADE_AUDITON	error setting the mask using auditon(2).
 */
int
auditd_set_namask(void)
{
	au_mask_t aumask;
	char naeventstr[NA_EVENT_STR_SIZE];
	                 
	if ((getacna(naeventstr, NA_EVENT_STR_SIZE) != 0) || 
	    (getauditflagsbin(naeventstr, &aumask) != 0)) 
		return (ADE_PARSE);

	if (audit_set_kmask(&aumask, sizeof(aumask)) != 0)
		return (ADE_AUDITON);

	return (ADE_NOERR);
}

/*
 * Set the audit control policy if a policy is configured in audit_control(5),
 * implement the policy. However, if one isn't defined or if there is an error
 * parsing the control file, set AUDIT_CNT to avoid leaving the system in a
 * fragile state.  Return:
 *	ADE_NOERR 	on success,
 *	ADE_PARSE	error parsing audit_control(5),
 *	ADE_AUDITON	error setting policy using auditon(2).
 */
int
auditd_set_policy(void)
{
	int policy;
	char polstr[POL_STR_SIZE];

	if ((getacpol(polstr, POL_STR_SIZE) != 0) || 
            (au_strtopol(polstr, &policy) != 0)) {
		policy = AUDIT_CNT;
		if (audit_set_policy(&policy) != 0)
			return (ADE_AUDITON);
		return (ADE_PARSE);
        }

	if (audit_set_policy(&policy) != 0)
		return (ADE_AUDITON);

	return (ADE_NOERR);
}

/* 
 * Set trail rotation size.  Return:
 *	ADE_NOERR 	on success,
 *	ADE_PARSE	error parsing audit_control(5),
 *	ADE_AUDITON	error setting file size using auditon(2).
 */
int
auditd_set_fsize(void)
{
	size_t filesz;
	au_fstat_t au_fstat;

	/*
	 * Set trail rotation size.
	 */
	if (getacfilesz(&filesz) != 0)
		return (ADE_PARSE);

	bzero(&au_fstat, sizeof(au_fstat));
	au_fstat.af_filesz = filesz;
	if (audit_set_fsize(&au_fstat, sizeof(au_fstat)) != 0)
		return (ADE_AUDITON);

        return (ADE_NOERR);
}

/*
 * Create the new audit file with appropriate permissions and ownership.  Try
 * to clean up if something goes wrong.
 */
static int
open_trail(char *fname, gid_t gid)
{
	int error, fd;
	
	fd = open(fname, O_RDONLY | O_CREAT, S_IRUSR | S_IRGRP);
	if (fd < 0)
		return (-1);
	if (fchown(fd, -1, gid) < 0) {
		error = errno;
		close(fd);
		(void)unlink(fname);
		errno = error;
		return (-1);
	}
	return (fd);
}

/*
 * Create the new audit trail file, swap with existing audit file.  Arguments
 * include timestamp for the filename, a pointer to a string for returning the
 * new file name, GID for trail file, and audit_warn function pointer for 
 * 'getacdir()' errors.  Returns:
 *  	ADE_NOERR	on success,
 *  	ADE_STRERR	if the file name string could not be created,
 *  	ADE_SWAPERR	if the audit trail file could not be swapped,
 *	ADE_ACTL 	if the auditctl(2) call failed but file swap still
 *			successful.
 *	ADE_ACTLERR	if the auditctl(2) call failed and file swap failed.
 *	ADE_SYMLINK	if symlink(2) failed updating the current link.
 */
int
auditd_swap_trail(char *TS, char **newfile, gid_t gid, 
    int (*warn_getacdir)(char *))
{
	char timestr[FILENAME_LEN];
	char *fn;
	struct dir_ent *dirent;
	int fd;
	int error;
	int saverrno = 0;
                
	if (strlen(TS) !=  (TIMESTAMP_LEN - 1) ||
	    snprintf(timestr, FILENAME_LEN, "%s.%s", TS, NOT_TERMINATED) < 0) {
		errno = EINVAL;
		return (ADE_STRERR);
	}
                
	/* Try until we succeed. */
	TAILQ_FOREACH(dirent, &dir_q, dirs) {
		if (dirent->hardlim) 
			continue;
		if ((fn = affixdir(timestr, dirent)) == NULL)
			return (ADE_STRERR);

		/*
		 * Create and open the file; then close and pass to the
		 * kernel if all went well.
		 */
		fd = open_trail(fn, gid);
		if (fd >= 0) {
			error = auditctl(fn);
			if (error) {
				/* 
				 * auditctl failed setting log file.  
				 * Try again.
				 */
				saverrno = errno;
                                close(fd);
                        } else {
                                /* Success. */
                                *newfile = fn;
                                close(fd);
				if (error)
					return (error);
				if (saverrno) {
					/*
					 * auditctl() failed but still
					 * successful. Return errno and "soft" 
					 * error.
					 */
					errno = saverrno;
					return (ADE_ACTL);
				}
                                return (ADE_NOERR);
                        }
                }

		/*
		 * Tell the administrator about lack of permissions for dir.
		 */
		if (warn_getacdir != NULL)
			(*warn_getacdir)(dirent->dirname);
	}
	if (saverrno) {
		errno = saverrno;
		return (ADE_ACTLERR);
	} else
		return (ADE_SWAPERR);
}

/*
 * Mask calling process from being audited. Returns:
 *	ADE_NOERR	on success,
 *	ADE_SETAUDIT	if setaudit(2) fails.
 */
#ifdef __APPLE__
int
auditd_prevent_audit(void)
{
	auditinfo_addr_t aia;

	/* 
	 * To prevent event feedback cycles and avoid audit becoming stalled if
	 * auditing is suspended we mask this processes events from being
	 * audited.  We allow the uid, tid, and mask fields to be implicitly
	 * set to zero, but do set the audit session ID to the PID. 
	 *
	 * XXXRW: Is there more to it than this?
	 */
	bzero(&aia, sizeof(aia));
	aia.ai_asid = AU_ASSIGN_ASID;
	aia.ai_termid.at_type = AU_IPv4;
	if (setaudit_addr(&aia, sizeof(aia)) != 0)
		return (ADE_SETAUDIT); 
	return (ADE_NOERR);
}
#else
int
auditd_prevent_audit(void)
{
	auditinfo_t ai;

	/* 
	 * To prevent event feedback cycles and avoid audit becoming stalled if
	 * auditing is suspended we mask this processes events from being
	 * audited.  We allow the uid, tid, and mask fields to be implicitly
	 * set to zero, but do set the audit session ID to the PID. 
	 *
	 * XXXRW: Is there more to it than this?
	 */
	bzero(&ai, sizeof(ai));
	ai.ai_asid = getpid();
	if (setaudit(&ai) != 0)
		return (ADE_SETAUDIT); 
	return (ADE_NOERR);
}
#endif /* __APPLE__ */

/*
 * Generate and submit audit record for audit startup or shutdown.  The event
 * argument can be AUE_audit_recovery, AUE_audit_startup or
 * AUE_audit_shutdown. The path argument will add a path token, if not NULL.
 * Returns:
 *	AUE_NOERR	on success,
 *	ADE_NOMEM	if memory allocation fails,
 * 	ADE_AU_OPEN	if au_open(3) fails,
 *	ADE_AU_CLOSE	if au_close(3) fails.
 */
int
auditd_gen_record(int event, char *path)
{
	int aufd;
	uid_t uid;
	pid_t pid;
	char *autext = NULL;
	token_t *tok;
	struct auditinfo_addr aia;

	if (event == AUE_audit_startup)
		asprintf(&autext, "%s::Audit startup", getprogname());
	else if (event == AUE_audit_shutdown)
		asprintf(&autext, "%s::Audit shutdown", getprogname());
	else if (event == AUE_audit_recovery)
		asprintf(&autext, "%s::Audit recovery", getprogname());
	else 
		return (ADE_INVAL);
	if (autext == NULL)
		return (ADE_NOMEM);

	if ((aufd = au_open()) == -1) {
		free(autext);
		return (ADE_AU_OPEN);
	}
	bzero(&aia, sizeof(aia));
	uid = getuid(); pid = getpid();
	if ((tok = au_to_subject32_ex(uid, geteuid(), getegid(), uid, getgid(),
	     pid, pid, &aia.ai_termid)) != NULL)
		au_write(aufd, tok);
	if ((tok = au_to_text(autext)) != NULL)
		au_write(aufd, tok);
	free(autext);
	if (path != NULL && (tok = au_to_path(path)) != NULL)
		au_write(aufd, tok);
	if ((tok = au_to_return32(0, 0)) != NULL)
		au_write(aufd, tok);
	if (au_close(aufd, 1, event) == -1)
		return (ADE_AU_CLOSE);

	return (ADE_NOERR);
}

/*
 * Check for a 'current' symlink and do crash recovery, if needed. Create a new
 * 'current' symlink. The argument 'curfile' is the file the 'current' symlink
 * should point to.  Returns:
 *	ADE_NOERR	on success,
 *  	ADE_AU_OPEN	if au_open(3) fails,
 *  	ADE_AU_CLOSE	if au_close(3) fails.
 *	ADE_RENAME	if error renaming audit trail file,
 *	ADE_READLINK	if error reading the 'current' link,
 *	ADE_SYMLINK	if error creating 'current' link.
 */
int
auditd_new_curlink(char *curfile)
{
	int len, err;
	char *ptr;
	char *path = NULL;
	struct stat sb;
	char recoveredname[MAXPATHLEN];
	char newname[MAXPATHLEN];

	/*
	 * Check to see if audit was shutdown properly.  If not, clean up,
	 * recover previous audit trail file, and generate audit record.
	 */
	len = readlink(AUDIT_CURRENT_LINK, recoveredname, MAXPATHLEN - 1);
	if (len > 0) {
		/* 'current' exist but is it pointing at a valid file?  */
		recoveredname[len++] = '\0';
		if (stat(recoveredname, &sb) == 0) { 
			/* Yes, rename it to a crash recovery file. */
			strlcpy(newname, recoveredname, MAXPATHLEN);

			if ((ptr = strstr(newname, NOT_TERMINATED)) != NULL) {
				memcpy(ptr, CRASH_RECOVERY, POSTFIX_LEN);
				if (rename(recoveredname, newname) != 0)
					return (ADE_RENAME);
			} else
				return (ADE_STRERR);

			path = newname;
		}

		/* 'current' symlink is (now) invalid so remove it. */
		(void) unlink(AUDIT_CURRENT_LINK);

		/* Note the crash recovery in current audit trail */
		err = auditd_gen_record(AUE_audit_recovery, path);
		if (err)
			return (err);
	}

	if (len < 0 && errno != ENOENT)
		return (ADE_READLINK);

	if (symlink(curfile, AUDIT_CURRENT_LINK) != 0)
		return (ADE_SYMLINK);

	return (0);
}

/*
 * Do just what we need to quickly start auditing.  Assume no system logging or
 * notify.  Return:
 *   0	 on success,
 *  -1   on failure.
 */
int
audit_quick_start(void)
{
	int err;
	char *newfile = NULL;
	time_t tt;
	char TS[TIMESTAMP_LEN];
	int ret = 0;

	/* 
	 * Mask auditing of this process.
	 */
	if (auditd_prevent_audit() != 0)
		return (-1);

	/*
	 * Read audit_control and get log directories.
	 */
        err = auditd_read_dirs(NULL, NULL);
	if (err != ADE_NOERR && err != ADE_SOFTLIM)
		return (-1);

	/*
	 *  Create a new audit trail log.
	 */
	if (getTSstr(tt, TS, TIMESTAMP_LEN) != 0)
		return (-1);
	err = auditd_swap_trail(TS, &newfile, getgid(), NULL);
	if (err != ADE_NOERR && err != ADE_ACTL) {
		ret = -1;
		goto out;
	}

	/*
	 * Add the current symlink and recover from crash, if needed. 
	 */
	if (auditd_new_curlink(newfile) != 0) {
		ret = -1;
		goto out;
	}

	/*
	 * At this point auditing has started so generate audit start-up record.
	 */
	if (auditd_gen_record(AUE_audit_startup, NULL) != 0) {
		ret = -1;
		goto out;
	}

	/*
	 *  Configure the audit controls.
	 */
	(void) auditd_set_evcmap();
	(void) auditd_set_namask();
	(void) auditd_set_policy();
	(void) auditd_set_fsize();
	(void) auditd_set_minfree();
	(void) auditd_set_host();

out:
	if (newfile != NULL)
		free(newfile);

	return (ret);
}

/*
 * Shut down auditing quickly.  Assumes that is only called on system shutdown.
 * Returns:
 *	 0	on success,
 *	-1	on failure.
 */
int
audit_quick_stop(void)
{
	int len;
	int cond;
	char *ptr;
	time_t tt;
	char oldname[MAXPATHLEN];
	char newname[MAXPATHLEN];
	char TS[TIMESTAMP_LEN];

	/*
	 * Auditing already disabled?
	 */
	if (audit_get_cond(&cond) != 0)
		return (-1);
	if (cond == AUC_NOAUDIT)
		return (0);

	/*
	 *  Generate audit shutdown record.
	 */
	(void) auditd_gen_record(AUE_audit_shutdown, NULL);

	/*
	 * Shutdown auditing in the kernel.
	 */
	cond = AUC_DISABLED;
	if (audit_set_cond(&cond) != 0)
		return (-1);
#ifdef	__BSM_INTERNAL_NOTIFY_KEY
	notify_post(__BSM_INTERNAL_NOTIFY_KEY);
#endif

	/*
	 * Rename last audit trail and remove 'current' link.
	 */
	len = readlink(AUDIT_CURRENT_LINK, oldname, MAXPATHLEN - 1);
	if (len < 0)
		return (-1);
	oldname[len++] = '\0';

	if (getTSstr(tt, TS, TIMESTAMP_LEN) != 0)
		return (-1);

	strlcpy(newname, oldname, len);

	if ((ptr = strstr(newname, NOT_TERMINATED)) != NULL) {
		memcpy(ptr, TS, POSTFIX_LEN);
		if (rename(oldname, newname) != 0)
			return (-1);
	} else
		return (-1);
	
	(void) unlink(AUDIT_CURRENT_LINK);

	return (0);
}