summaryrefslogtreecommitdiffstats
path: root/plugins/sudoers/match.c
blob: 445bdb2486e31360c1639a2693eaf1214c1bbe62 (plain)
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
/*
 * SPDX-License-Identifier: ISC
 *
 * Copyright (c) 1996, 1998-2005, 2007-2023
 *	Todd C. Miller <Todd.Miller@sudo.ws>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * Sponsored in part by the Defense Advanced Research Projects
 * Agency (DARPA) and Air Force Research Laboratory, Air Force
 * Materiel Command, USAF, under agreement number F39502-99-1-0512.
 */

/*
 * This is an open source non-commercial project. Dear PVS-Studio, please check it.
 * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
 */

#include <config.h>

#include <sys/stat.h>
#ifdef HAVE_SYS_SYSTEMINFO_H
# include <sys/systeminfo.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef HAVE_STRINGS_H
# include <strings.h>
#endif /* HAVE_STRINGS_H */
#include <unistd.h>
#ifdef HAVE_NETGROUP_H
# include <netgroup.h>
#else
# include <netdb.h>
#endif /* HAVE_NETGROUP_H */
#include <dirent.h>
#include <fcntl.h>
#include <pwd.h>
#include <grp.h>
#include <errno.h>
#ifdef HAVE_FNMATCH
# include <fnmatch.h>
#else
# include "compat/fnmatch.h"
#endif /* HAVE_FNMATCH */

#include "sudoers.h"
#include <gram.h>

static struct member_list empty = TAILQ_HEAD_INITIALIZER(empty);

/*
 * Check whether user described by pw matches member.
 * Returns ALLOW, DENY or UNSPEC.
 */
int
user_matches(struct sudoers_parse_tree *parse_tree, const struct passwd *pw,
    const struct member *m)
{
    const char *lhost = parse_tree->lhost ? parse_tree->lhost : user_runhost;
    const char *shost = parse_tree->shost ? parse_tree->shost : user_srunhost;
    int matched = UNSPEC;
    struct alias *a;
    debug_decl(user_matches, SUDOERS_DEBUG_MATCH);

    switch (m->type) {
	case ALL:
	    matched = !m->negated;
	    break;
	case NETGROUP:
	    if (netgr_matches(m->name,
		def_netgroup_tuple ? lhost : NULL,
		def_netgroup_tuple ? shost : NULL, pw->pw_name))
		matched = !m->negated;
	    break;
	case USERGROUP:
	    if (usergr_matches(m->name, pw->pw_name, pw))
		matched = !m->negated;
	    break;
	case ALIAS:
	    if ((a = alias_get(parse_tree, m->name, USERALIAS)) != NULL) {
		/* XXX */
		int rc = userlist_matches(parse_tree, pw, &a->members);
		if (rc != UNSPEC)
		    matched = m->negated ? !rc : rc;
		alias_put(a);
		break;
	    }
	    FALLTHROUGH;
	case WORD:
	    if (userpw_matches(m->name, pw->pw_name, pw))
		matched = !m->negated;
	    break;
    }
    debug_return_int(matched);
}

/*
 * Check for user described by pw in a list of members.
 * Returns ALLOW, DENY or UNSPEC.
 */
int
userlist_matches(struct sudoers_parse_tree *parse_tree, const struct passwd *pw,
    const struct member_list *list)
{
    struct member *m;
    int matched = UNSPEC;
    debug_decl(userlist_matches, SUDOERS_DEBUG_MATCH);

    TAILQ_FOREACH_REVERSE(m, list, member_list, entries) {
	if ((matched = user_matches(parse_tree, pw, m)) != UNSPEC)
	    break;
    }
    debug_return_int(matched);
}

struct gid_list *
runas_getgroups(void)
{
    const struct passwd *pw;
    debug_decl(runas_getgroups, SUDOERS_DEBUG_MATCH);

    if (def_preserve_groups) {
	sudo_gidlist_addref(user_gid_list);
	debug_return_ptr(user_gid_list);
    }

    /* Only use results from a group db query, not the front end. */
    pw = runas_pw ? runas_pw : sudo_user.pw;
    debug_return_ptr(sudo_get_gidlist(pw, ENTRY_TYPE_QUERIED));
}

/*
 * Check for user described by pw in a list of members.
 * If both lists are empty compare against def_runas_default.
 * Returns ALLOW, DENY or UNSPEC.
 */
int
runaslist_matches(struct sudoers_parse_tree *parse_tree,
    const struct member_list *user_list, const struct member_list *group_list,
    struct member **matching_user, struct member **matching_group)
{
    const char *lhost = parse_tree->lhost ? parse_tree->lhost : user_runhost;
    const char *shost = parse_tree->shost ? parse_tree->shost : user_srunhost;
    int user_matched = UNSPEC;
    int group_matched = UNSPEC;
    struct member *m;
    struct alias *a;
    int rc;
    debug_decl(runaslist_matches, SUDOERS_DEBUG_MATCH);

    if (ISSET(sudo_user.flags, RUNAS_USER_SPECIFIED) || !ISSET(sudo_user.flags, RUNAS_GROUP_SPECIFIED)) {
	/* If no runas user or runas group listed in sudoers, use default. */
	if (user_list == NULL && group_list == NULL) {
	    debug_return_int(userpw_matches(def_runas_default,
		runas_pw->pw_name, runas_pw));
	}

	if (user_list != NULL) {
	    TAILQ_FOREACH_REVERSE(m, user_list, member_list, entries) {
		switch (m->type) {
		    case ALL:
			user_matched = !m->negated;
			break;
		    case NETGROUP:
			if (netgr_matches(m->name,
			    def_netgroup_tuple ? lhost : NULL,
			    def_netgroup_tuple ? shost : NULL,
			    runas_pw->pw_name))
			    user_matched = !m->negated;
			break;
		    case USERGROUP:
			if (usergr_matches(m->name, runas_pw->pw_name, runas_pw))
			    user_matched = !m->negated;
			break;
		    case ALIAS:
			a = alias_get(parse_tree, m->name, RUNASALIAS);
			if (a != NULL) {
			    rc = runaslist_matches(parse_tree, &a->members,
				&empty, matching_user, NULL);
			    if (rc != UNSPEC)
				user_matched = m->negated ? !rc : rc;
			    alias_put(a);
			    break;
			}
			FALLTHROUGH;
		    case WORD:
			if (userpw_matches(m->name, runas_pw->pw_name, runas_pw))
			    user_matched = !m->negated;
			break;
		    case MYSELF:
			if (!ISSET(sudo_user.flags, RUNAS_USER_SPECIFIED) ||
			    strcmp(user_name, runas_pw->pw_name) == 0)
			    user_matched = !m->negated;
			break;
		}
		if (user_matched != UNSPEC) {
		    if (matching_user != NULL && m->type != ALIAS)
			*matching_user = m;
		    break;
		}
	    }
	}
    }

    /*
     * Skip checking runas group if none was specified.
     */
    if (ISSET(sudo_user.flags, RUNAS_GROUP_SPECIFIED)) {
	if (user_matched == UNSPEC) {
	    if (strcmp(user_name, runas_pw->pw_name) == 0)
		user_matched = ALLOW;	/* only changing group */
	}
	if (group_list != NULL) {
	    TAILQ_FOREACH_REVERSE(m, group_list, member_list, entries) {
		switch (m->type) {
		    case ALL:
			group_matched = !m->negated;
			break;
		    case ALIAS:
			a = alias_get(parse_tree, m->name, RUNASALIAS);
			if (a != NULL) {
			    rc = runaslist_matches(parse_tree, &empty,
				&a->members, NULL, matching_group);
			    if (rc != UNSPEC)
				group_matched = m->negated ? !rc : rc;
			    alias_put(a);
			    break;
			}
			FALLTHROUGH;
		    case WORD:
			if (group_matches(m->name, runas_gr))
			    group_matched = !m->negated;
			break;
		}
		if (group_matched != UNSPEC) {
		    if (matching_group != NULL && m->type != ALIAS)
			*matching_group = m;
		    break;
		}
	    }
	}
	if (group_matched == UNSPEC) {
	    struct gid_list *runas_groups;
	    /*
	     * The runas group was not explicitly allowed by sudoers.
	     * Check whether it is one of the target user's groups.
	     */
	    if (runas_pw->pw_gid == runas_gr->gr_gid) {
		group_matched = ALLOW;	/* runas group matches passwd db */
	    } else if ((runas_groups = runas_getgroups()) != NULL) {
		int i;

		for (i = 0; i < runas_groups->ngids; i++) {
		    if (runas_groups->gids[i] == runas_gr->gr_gid) {
			group_matched = ALLOW;	/* matched aux group vector */
			break;
		    }
		}
		sudo_gidlist_delref(runas_groups);
	    }
	}
    }

    if (user_matched == DENY || group_matched == DENY)
	debug_return_int(DENY);
    if (user_matched == group_matched || runas_gr == NULL)
	debug_return_int(user_matched);
    debug_return_int(UNSPEC);
}

/*
 * Check for lhost and shost in a list of members.
 * Returns ALLOW, DENY or UNSPEC.
 */
static int
hostlist_matches_int(struct sudoers_parse_tree *parse_tree,
    const struct passwd *pw, const char *lhost, const char *shost,
    const struct member_list *list)
{
    struct member *m;
    int matched = UNSPEC;
    debug_decl(hostlist_matches, SUDOERS_DEBUG_MATCH);

    TAILQ_FOREACH_REVERSE(m, list, member_list, entries) {
	matched = host_matches(parse_tree, pw, lhost, shost, m);
	if (matched != UNSPEC)
	    break;
    }
    debug_return_int(matched);
}

/*
 * Check for user_runhost and user_srunhost in a list of members.
 * Returns ALLOW, DENY or UNSPEC.
 */
int
hostlist_matches(struct sudoers_parse_tree *parse_tree, const struct passwd *pw,
    const struct member_list *list)
{
    const char *lhost = parse_tree->lhost ? parse_tree->lhost : user_runhost;
    const char *shost = parse_tree->shost ? parse_tree->shost : user_srunhost;

    return hostlist_matches_int(parse_tree, pw, lhost, shost, list);
}

/*
 * Check whether host or shost matches member.
 * Returns ALLOW, DENY or UNSPEC.
 */
int
host_matches(struct sudoers_parse_tree *parse_tree, const struct passwd *pw,
    const char *lhost, const char *shost, const struct member *m)
{
    struct alias *a;
    int matched = UNSPEC;
    debug_decl(host_matches, SUDOERS_DEBUG_MATCH);

    switch (m->type) {
	case ALL:
	    matched = !m->negated;
	    break;
	case NETGROUP:
	    if (netgr_matches(m->name, lhost, shost,
		def_netgroup_tuple ? pw->pw_name : NULL))
		matched = !m->negated;
	    break;
	case NTWKADDR:
	    if (addr_matches(m->name))
		matched = !m->negated;
	    break;
	case ALIAS:
	    a = alias_get(parse_tree, m->name, HOSTALIAS);
	    if (a != NULL) {
		/* XXX */
		int rc = hostlist_matches_int(parse_tree, pw, lhost, shost,
		    &a->members);
		if (rc != UNSPEC)
		    matched = m->negated ? !rc : rc;
		alias_put(a);
		break;
	    }
	    FALLTHROUGH;
	case WORD:
	    if (hostname_matches(shost, lhost, m->name))
		matched = !m->negated;
	    break;
    }
    sudo_debug_printf(SUDO_DEBUG_DEBUG,
	"host %s (%s) matches sudoers host %s%s: %s", lhost, shost,
	m->negated ? "!" : "", m->name ? m->name : "ALL",
	matched == true ? "true" : "false");
    debug_return_int(matched);
}

/*
 * Check for cmnd and args in a list of members.
 * Returns ALLOW, DENY or UNSPEC.
 */
int
cmndlist_matches(struct sudoers_parse_tree *parse_tree,
    const struct member_list *list, const char *runchroot,
    struct cmnd_info *info)
{
    struct member *m;
    int matched = UNSPEC;
    debug_decl(cmndlist_matches, SUDOERS_DEBUG_MATCH);

    TAILQ_FOREACH_REVERSE(m, list, member_list, entries) {
	matched = cmnd_matches(parse_tree, m, runchroot, info);
	if (matched != UNSPEC)
	    break;
    }
    debug_return_int(matched);
}

/*
 * Check cmnd and args.
 * Returns ALLOW, DENY or UNSPEC.
 */
int
cmnd_matches(struct sudoers_parse_tree *parse_tree, const struct member *m,
    const char *runchroot, struct cmnd_info *info)
{
    struct alias *a;
    struct sudo_command *c;
    int rc, matched = UNSPEC;
    debug_decl(cmnd_matches, SUDOERS_DEBUG_MATCH);

    switch (m->type) {
	case ALL:
	case COMMAND:
	    c = (struct sudo_command *)m->name;
	    if (command_matches(c->cmnd, c->args, runchroot, info, &c->digests))
		matched = !m->negated;
	    break;
	case ALIAS:
	    a = alias_get(parse_tree, m->name, CMNDALIAS);
	    if (a != NULL) {
		rc = cmndlist_matches(parse_tree, &a->members, runchroot, info);
		if (rc != UNSPEC)
		    matched = m->negated ? !rc : rc;
		alias_put(a);
	    }
	    break;
    }
    debug_return_int(matched);
}

/*
 * Like cmnd_matches() but only matches against the ALL command.
 * Returns ALLOW, DENY or UNSPEC.
 */
int
cmnd_matches_all(struct sudoers_parse_tree *parse_tree, const struct member *m,
    const char *runchroot, struct cmnd_info *info)
{
    const bool negated = m->negated;
    struct sudo_command *c;
    int matched = UNSPEC;
    struct alias *a;
    debug_decl(cmnd_matches_all, SUDOERS_DEBUG_MATCH);

    switch (m->type) {
	case ALL:
	    c = (struct sudo_command *)m->name;
	    if (command_matches(c->cmnd, c->args, runchroot, info, &c->digests))
		matched = !negated;
	    break;
	case ALIAS:
	    a = alias_get(parse_tree, m->name, CMNDALIAS);
	    if (a != NULL) {
		TAILQ_FOREACH_REVERSE(m, &a->members, member_list, entries) {
		    matched = cmnd_matches_all(parse_tree, m, runchroot, info);
		    if (matched != UNSPEC) {
			if (negated)
			    matched = !matched;
			break;
		    }
		}
		alias_put(a);
	    }
	    break;
    }
    debug_return_int(matched);
}

/*
 * Returns true if the hostname matches the pattern, else false
 */
bool
hostname_matches(const char *shost, const char *lhost, const char *pattern)
{
    const char *host;
    bool rc;
    debug_decl(hostname_matches, SUDOERS_DEBUG_MATCH);

    host = strchr(pattern, '.') != NULL ? lhost : shost;
    if (has_meta(pattern)) {
	rc = !fnmatch(pattern, host, FNM_CASEFOLD);
    } else {
	rc = !strcasecmp(host, pattern);
    }
    debug_return_bool(rc);
}

/*
 * Returns true if the user/uid from sudoers matches the specified user/uid,
 * else returns false.
 */
bool
userpw_matches(const char *sudoers_user, const char *user, const struct passwd *pw)
{
    const char *errstr;
    uid_t uid;
    bool rc;
    debug_decl(userpw_matches, SUDOERS_DEBUG_MATCH);

    if (pw != NULL && *sudoers_user == '#') {
	uid = (uid_t) sudo_strtoid(sudoers_user + 1, &errstr);
	if (errstr == NULL && uid == pw->pw_uid) {
	    rc = true;
	    goto done;
	}
    }
    if (def_case_insensitive_user)
	rc = strcasecmp(sudoers_user, user) == 0;
    else
	rc = strcmp(sudoers_user, user) == 0;
done:
    sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,
	"user %s matches sudoers user %s: %s",
	user, sudoers_user, rc ? "true" : "false");
    debug_return_bool(rc);
}

/*
 * Returns true if the group/gid from sudoers matches the specified group/gid,
 * else returns false.
 */
bool
group_matches(const char *sudoers_group, const struct group *gr)
{
    const char *errstr;
    gid_t gid;
    bool rc;
    debug_decl(group_matches, SUDOERS_DEBUG_MATCH);

    if (*sudoers_group == '#') {
	gid = (gid_t) sudo_strtoid(sudoers_group + 1, &errstr);
	if (errstr == NULL && gid == gr->gr_gid) {
	    rc = true;
	    goto done;
	}
    }
    if (def_case_insensitive_group)
	rc = strcasecmp(sudoers_group, gr->gr_name) == 0;
    else
	rc = strcmp(sudoers_group, gr->gr_name) == 0;
done:
    sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,
	"group %s matches sudoers group %s: %s",
	gr->gr_name, sudoers_group, rc ? "true" : "false");
    debug_return_bool(rc);
}

/*
 * Returns true if the given user belongs to the named group,
 * else returns false.
 */
bool
usergr_matches(const char *group, const char *user, const struct passwd *pw)
{
    bool matched = false;
    struct passwd *pw0 = NULL;
    debug_decl(usergr_matches, SUDOERS_DEBUG_MATCH);

    /* Make sure we have a valid usergroup, sudo style */
    if (*group++ != '%') {
	sudo_debug_printf(SUDO_DEBUG_DIAG, "user group %s has no leading '%%'",
	    group);
	goto done;
    }

    /* Query group plugin for %:name groups. */
    if (*group == ':' && def_group_plugin) {
	if (group_plugin_query(user, group + 1, pw) == true)
	    matched = true;
	goto done;
    }

    /* Look up user's primary gid in the passwd file. */
    if (pw == NULL) {
	if ((pw0 = sudo_getpwnam(user)) == NULL) {
	    sudo_debug_printf(SUDO_DEBUG_DIAG, "unable to find %s in passwd db",
		user);
	    goto done;
	}
	pw = pw0;
    }

    if (user_in_group(pw, group)) {
	matched = true;
	goto done;
    }

    /* Query the group plugin for Unix groups too? */
    if (def_group_plugin && def_always_query_group_plugin) {
	if (group_plugin_query(user, group, pw) == true) {
	    matched = true;
	    goto done;
	}
    }

done:
    if (pw0 != NULL)
	sudo_pw_delref(pw0);

    sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,
	"user %s matches group %s: %s", user, group, matched ? "true" : "false");
    debug_return_bool(matched);
}

#if defined(HAVE_GETDOMAINNAME) || defined(SI_SRPC_DOMAIN)
/*
 * Check the domain for invalid characters.
 * Linux getdomainname(2) returns (none) if no domain is set.
 */
static bool
valid_domain(const char *domain)
{
    const char *cp;
    debug_decl(valid_domain, SUDOERS_DEBUG_MATCH);

    for (cp = domain; *cp != '\0'; cp++) {
	/* Check for illegal characters, Linux may use "(none)". */
	if (*cp == '(' || *cp == ')' || *cp == ',' || *cp == ' ')
	    break;
    }
    if (cp == domain || *cp != '\0')
	debug_return_bool(false);
    debug_return_bool(true);
}

/*
 * Get NIS-style domain name and copy from static storage or NULL if none.
 */
const char *
sudo_getdomainname(void)
{
    static char *domain;
    static bool initialized;
    debug_decl(sudo_getdomainname, SUDOERS_DEBUG_MATCH);

    if (!initialized) {
	size_t host_name_max;
	int rc;

# ifdef _SC_HOST_NAME_MAX
	host_name_max = (size_t)sysconf(_SC_HOST_NAME_MAX);
	if (host_name_max == (size_t)-1)
# endif
	    host_name_max = 255;    /* POSIX and historic BSD */

	domain = malloc(host_name_max + 1);
	if (domain != NULL) {
	    domain[0] = '\0';
# ifdef SI_SRPC_DOMAIN
	    rc = sysinfo(SI_SRPC_DOMAIN, domain, host_name_max + 1);
# else
	    rc = getdomainname(domain, host_name_max + 1);
# endif
	    if (rc == -1 || !valid_domain(domain)) {
		/* Error or invalid domain name. */
		free(domain);
		domain = NULL;
	    }
	} else {
	    /* XXX - want to pass error back to caller */
	    sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO,
		"unable to allocate memory");
	}
	initialized = true;
    }
    debug_return_str(domain);
}
#else
const char *
sudo_getdomainname(void)
{
    debug_decl(sudo_getdomainname, SUDOERS_DEBUG_MATCH);
    debug_return_ptr(NULL);
}
#endif /* HAVE_GETDOMAINNAME || SI_SRPC_DOMAIN */

/*
 * Returns true if "host" and "user" belong to the netgroup "netgr",
 * else return false.  Either of "lhost", "shost" or "user" may be NULL
 * in which case that argument is not checked...
 */
bool
netgr_matches(const char *netgr, const char *lhost, const char *shost, const char *user)
{
#ifdef HAVE_INNETGR
    const char *domain;
#endif
    bool rc = false;
    debug_decl(netgr_matches, SUDOERS_DEBUG_MATCH);

    if (!def_use_netgroups) {
	sudo_debug_printf(SUDO_DEBUG_INFO, "netgroups are disabled");
	debug_return_bool(false);
    }

#ifdef HAVE_INNETGR
    /* make sure we have a valid netgroup, sudo style */
    if (*netgr++ != '+') {
	sudo_debug_printf(SUDO_DEBUG_DIAG, "netgroup %s has no leading '+'",
	    netgr);
	debug_return_bool(false);
    }

    /* get the domain name (if any) */
    domain = sudo_getdomainname();

    if (innetgr(netgr, lhost, user, domain))
	rc = true;
    else if (lhost != shost && innetgr(netgr, shost, user, domain))
	rc = true;

    sudo_debug_printf(SUDO_DEBUG_DEBUG|SUDO_DEBUG_LINENO,
	"netgroup %s matches (%s|%s, %s, %s): %s", netgr, lhost ? lhost : "",
	shost ? shost : "", user ? user : "", domain ? domain : "",
	rc ? "true" : "false");
#endif /* HAVE_INNETGR */

    debug_return_bool(rc);
}