summaryrefslogtreecommitdiff
path: root/modules/pam_rhosts/pam_rhosts_auth.c
blob: a798c1f07af27107c7f2b35d594e0b553bd2f54a (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
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
/*----------------------------------------------------------------------
 * Modified for Linux-PAM by Al Longyear <longyear@netcom.com> 96/5/5
 * Modifications, Cristian Gafton 97/2/8
 * Modifications, Peter Allgeyer 97/3
 * Modifications (netgroups and fixes), Nicolai Langfeldt 97/3/21
 * Security fix: 97/10/2 - gethostbyname called repeatedly without care
 * Modification (added privategroup option) Andrew <morgan@transmeta.com>
 *----------------------------------------------------------------------
 * Copyright (c) 1983, 1993, 1994
 *	The Regents of the University of California.  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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University 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 THE REGENTS AND 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 THE REGENTS OR 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.
 */

#include "config.h"

#include <pwd.h>
#include <grp.h>
#include <ctype.h>
#include <stdarg.h>
#include <stdint.h>
#include <syslog.h>
#include <netdb.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <endian.h>
#include <sys/file.h>
#include <sys/time.h>
#include <arpa/inet.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/signal.h>
#include <sys/stat.h>
#ifdef HAVE_SYS_FSUID_H
#include <sys/fsuid.h>
#endif /* HAVE_SYS_FSUID_H */
#ifdef HAVE_NET_IF_H
#include <net/if.h>
#endif
#include <sys/types.h>
#include <sys/uio.h>
#include <netinet/in.h>

#ifndef MAXDNAME
#define MAXDNAME  256
#endif

#ifndef _PATH_HEQUIV
#define _PATH_HEQUIV "/etc/hosts.equiv"
#endif /* _PATH_HEQUIV */

#define USER_RHOSTS_FILE "/.rhosts"     /* prefixed by user's home dir */

#define PAM_SM_AUTH  /* only defines this management group */

#include <security/pam_modules.h>
#include <security/_pam_macros.h>
#include <security/pam_modutil.h>
#include <security/pam_ext.h>

/*
 * Options for this module
 */

struct _options {
    int  opt_no_hosts_equiv;
    int  opt_hosts_equiv_rootok;
    int  opt_no_rhosts;
    int  opt_debug;
    int  opt_nowarn;
    int  opt_disallow_null_authtok;
    int  opt_silent;
    int  opt_promiscuous;
    int  opt_suppress;
    int  opt_private_group;
    int  opt_no_uid_check;
    const char *superuser;
    const char *last_error;
};

static void
set_option (const pam_handle_t *pamh, struct _options *opts, const char *arg)
{
    if (strcmp(arg, "no_hosts_equiv") == 0) {
	opts->opt_no_hosts_equiv = 1;
	return;
    }

    if (strcmp(arg, "hosts_equiv_rootok") == 0) {
        opts->opt_hosts_equiv_rootok = 1;
        return;
    }

    if (strcmp(arg, "no_rhosts") == 0) {
	opts->opt_no_rhosts = 1;
	return;
    }

    if (strcmp(arg, "debug") == 0) {
	D(("debugging enabled"));
	opts->opt_debug = 1;
	return;
    }

    if (strcmp(arg, "no_warn") == 0) {
	opts->opt_nowarn = 1;
	return;
    }

    if (strcmp(arg, "promiscuous") == 0) {
	opts->opt_promiscuous = 1;   /* used to permit '+' in ...hosts file */
	return;
    }

    if (strcmp(arg, "suppress") == 0) {
	opts->opt_suppress = 1; /* used to suppress failure warning message */
	return;
    }

    if (strcmp(arg, "privategroup") == 0) {
	opts->opt_private_group = 1; /* used to permit group write on .rhosts
					file if group has same name as owner */
	return;
    }

    if (strcmp(arg, "no_uid_check") == 0) {
	opts->opt_no_uid_check = 1;  /* NIS optimization */
	return;
    }

    if (strncmp(arg, "superuser=", sizeof("superuser=")-1) == 0) {
	opts->superuser = arg+sizeof("superuser=")-1;
	return;
    }
    /*
     * All other options are ignored at the present time.
     */
    pam_syslog(pamh, LOG_WARNING, "unrecognized option '%s'", arg);
}

static void
set_parameters (const pam_handle_t *pamh, struct _options *opts,
		int flags, int argc, const char **argv)
{
    opts->opt_silent                = flags & PAM_SILENT;
    opts->opt_disallow_null_authtok = flags & PAM_DISALLOW_NULL_AUTHTOK;

    while (argc-- > 0) {
      set_option (pamh, opts, *argv);
      ++argv;
    }
}

/*
 * Obtain the name of the remote host. Currently, this is simply by
 * requesting the contents of the PAM_RHOST item.
 */

static int
pam_get_rhost (pam_handle_t *pamh, const char **rhost)
{
    int retval;
    const void *current;

    retval = pam_get_item (pamh, PAM_RHOST, &current);
    if (retval != PAM_SUCCESS)
        return retval;

    if (current == NULL) {
	return PAM_AUTH_ERR;
    }
    *rhost = current;

    return retval;        /* pass on any error from conversation */
}

/*
 * Obtain the name of the remote user. Currently, this is simply by
 * requesting the contents of the PAM_RUSER item.
 */

static int
pam_get_ruser(pam_handle_t *pamh, const char **ruser)
{
    int retval;
    const void *current;

    retval = pam_get_item (pamh, PAM_RUSER, &current);
    if (retval != PAM_SUCCESS) {
        return retval;
    }

    if (current == NULL) {
	return PAM_AUTH_ERR;
    }
    *ruser = current;

    return retval;        /* pass on any error from conversation */
}

/*
 * Returns 1 if positive match, 0 if no match, -1 if negative match.
 */

static int
__icheckhost (pam_handle_t *pamh, struct _options *opts, u_int32_t raddr
	      , register char *lhost, const char *rhost)
{
    struct hostent *hp;
    u_int32_t laddr;
    int negate=1;    /* Multiply return with this to get -1 instead of 1 */
    char **pp;
    const void *user;

    /* Check nis netgroup.  We assume that pam has done all needed
       paranoia checking before we are handed the rhost */
    if (strncmp("+@",lhost,2) == 0)
      return(innetgr(&lhost[2],rhost,NULL,NULL));

    if (strncmp("-@",lhost,2) == 0)
      return(-innetgr(&lhost[2],rhost,NULL,NULL));

    /* -host */
    if (strncmp("-",lhost,1) == 0) {
	negate=-1;
	lhost++;
    } else if (strcmp("+",lhost) == 0) {
        (void) pam_get_item(pamh, PAM_USER, &user);
        D(("user %s has a `+' host entry", user));
	if (opts->opt_promiscuous)
	    return (1);                     /* asking for trouble, but ok.. */
	/* If not promiscuous: handle as negative */
	return (-1);
    } else if (strncmp("+",lhost,1) == 0) {
	/* '+hostname' is supposed to be equivalent to 'hostname' */
	lhost++;
    }


    /* Try for raw ip address first. */
    if (isdigit(*lhost) && (long)(laddr = inet_addr(lhost)) != -1)
	return (negate*(! (raddr ^ laddr)));

    /* Better be a hostname. */
    hp = gethostbyname(lhost);
    if (hp == NULL)
	return (0);

    /* Spin through ip addresses. */
    for (pp = hp->h_addr_list; *pp; ++pp)
	if (!memcmp (&raddr, *pp, sizeof (u_int32_t)))
	    return (negate);

    /* No match. */
    return (0);
}

/* Returns 1 on positive match, 0 on no match, -1 on negative match */

static int
__icheckuser (pam_handle_t *pamh, struct _options *opts,
	      const char *luser, const char *ruser)
{
    /*
      luser is user entry from .rhosts/hosts.equiv file
      ruser is user id on remote host
      */
    const void *user;

    /* [-+]@netgroup */
    if (strncmp("+@",luser,2) == 0)
	return (innetgr(&luser[2],NULL,ruser,NULL));

    if (strncmp("-@",luser,2) == 0)
	return (-innetgr(&luser[2],NULL,ruser,NULL));

    /* -user */
    if (strncmp("-",luser,1) == 0)
	return(-(strcmp(&luser[1],ruser) == 0));

    /* + */
    if (strcmp("+",luser) == 0) {
	(void) pam_get_item(pamh, PAM_USER, &user);
	pam_syslog(pamh, LOG_WARNING, "user %s has a `+' user entry",
		   (const char *) user);
	if (opts->opt_promiscuous)
	    return(1);
	/* If not promiscuous we handle it as a negative match */
	return(-1);
    }

    /* simple string match */
    return (strcmp(ruser, luser) == 0);
}

/*
 * Returns 1 for blank lines (or only comment lines) and 0 otherwise
 */

static int __isempty(char *p)
{
    while (*p && isspace(*p)) {
	++p;
    }

    return (*p == '\0' || *p == '#') ? 1:0 ;
}

/*
 * Returns 0 if positive match, 1 if _not_ ok.
 */

static int
__ivaliduser (pam_handle_t *pamh, struct _options *opts,
	      FILE *hostf, u_int32_t raddr,
	      const char *luser, const char *ruser, const char *rhost)
{
    register const char *user;
    register char *p;
    int hcheck, ucheck;
    int retval = 1;
#ifdef HAVE_GETLINE
    char *buf=NULL;
    int buflen=0;

    while (getline(&buf,&buflen,hostf) > 0) {
#else
    char buf[MAXHOSTNAMELEN + 128];                       /* host + login */

    while (fgets(buf, sizeof(buf), hostf) != NULL) {   /* hostf file line */
#endif
        p = buf;                              /* from beginning of file.. */

	/* Skip empty or comment lines */
	if (__isempty(p)) {
	    continue;
	}

	/* Skip lines that are too long. */
	if (strchr(p, '\n') == NULL) {
	    int ch = getc(hostf);

	    while (ch != '\n' && ch != EOF)
		ch = getc(hostf);
	    continue;
	}

	/*
	 * If there is a hostname at the start of the line.  Set it to
	 * lower case. A leading ' ' or '\t' indicates no hostname
	 */

	for (;*p && !isspace(*p); ++p) {
	    *p = tolower(*p);
	}

	/*
	 * next we want to find the permitted name for the remote user
	 */

	if (*p == ' ' || *p == '\t') {

	    /* <nul> terminate hostname and skip spaces */
	    for (*p++='\0'; *p && isspace(*p); ++p);

	    user = p;                   /* this is the user's name */
	    while (*p && !isspace(*p))
		++p;                    /* find end of user's name */
	} else
	    user = p;

	*p = '\0';              /* <nul> terminate username (+host?) */

	/* buf -> host(?) ; user -> username(?) */

	/* First check host part */
	hcheck=__icheckhost(pamh, opts, raddr, buf, rhost);

	if (hcheck<0)
	    break;

	if (hcheck) {
	    /* Then check user part */
	    if (! (*user))
		user = luser;

	    ucheck=__icheckuser(pamh, opts, user, ruser);

	    /* Positive 'host user' match? */
	    if (ucheck>0) {
		retval = 0;
		break;
	    }

	    /* Negative 'host -user' match? */
	    if (ucheck<0)
		break;

	    /* Neither, go on looking for match */
	}
    }
#ifdef HAVE_GETLINE
    if(buf)free(buf);
#endif

    return retval;
}

/*
 * New .rhosts strategy: We are passed an ip address. We spin through
 * hosts.equiv and .rhosts looking for a match. When the .rhosts only
 * has ip addresses, we don't have to trust a nameserver.  When it
 * contains hostnames, we spin through the list of addresses the nameserver
 * gives us and look for a match.
 *
 * Returns 0 if ok, -1 if not ok.
 */

static int
pam_iruserok(pam_handle_t *pamh,
	 struct _options *opts, u_int32_t raddr, int superuser,
	 const char *ruser, const char *luser, const char *rhost)
{
    const char *cp;
    struct stat sbuf;
    struct passwd *pwd;
    FILE *hostf;
    uid_t uid;
    int answer;
    char *fpath;

    if ((!superuser||opts->opt_hosts_equiv_rootok) && !opts->opt_no_hosts_equiv ) {

	/* try to open system hosts.equiv file */
	hostf = fopen (_PATH_HEQUIV, "r");
	if (hostf) {
	    answer = __ivaliduser(pamh, opts, hostf, raddr, luser
				  , ruser, rhost);
	    (void) fclose(hostf);
	    if (answer == 0)
		return 0;      /* remote host is equivalent to localhost */
	} /* else {
	    No hosts.equiv file on system.
	} */
    }

    if ( opts->opt_no_rhosts )
	return 1;

    /*
     * Identify user's local .rhosts file
     */

    pwd = pam_modutil_getpwnam(pamh, luser);
    if (pwd == NULL) {
	/*
	 * luser is assumed to be valid because of an earlier check for uid = 0
	 * we don't log this error twice. However, this shouldn't happen !
	 * --cristiang
	 */
	return(1);
    }

    if (asprintf (&fpath, "%s%s", pwd->pw_dir, USER_RHOSTS_FILE) < 0) {
       pam_syslog (pamh, LOG_ALERT, "Running out of memory");
       return 1;
    }

    /*
     * Change effective uid while _reading_ .rhosts. (not just
     * opening).  If root and reading an NFS mounted file system,
     * can't read files that are 0600 as .rhosts files should be.
     */

    /* We are root, this will not fail */
#ifdef __linux__
    /* If we are on linux the better way is setfsuid */
    uid = setfsuid(pwd->pw_uid);
    hostf = fopen(fpath, "r");
#else
    uid = geteuid();
    (void) seteuid(pwd->pw_uid);
    hostf = fopen(fpath, "r");
#endif

    if (hostf == NULL) {
        if (opts->opt_debug)
	    pam_syslog(pamh, LOG_DEBUG, "Could not open %s: %m", fpath);
	answer = 1;
	goto exit_function;
    }

    /*
     * If not a regular file, or is owned by someone other than
     * user or root or if writeable by anyone but the owner, quit.
     */

    cp = NULL;
    if (lstat(fpath, &sbuf) < 0 || !S_ISREG(sbuf.st_mode))
	cp = ".rhosts not regular file";
    else if (fstat(fileno(hostf), &sbuf) < 0)
	cp = ".rhosts fstat failed";
    else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid)
	cp = "bad .rhosts owner";
    else if (sbuf.st_mode & S_IWOTH)
	cp = ".rhosts writable by other!";
    else if (sbuf.st_mode & S_IWGRP) {

	/* private group caveat */
	if (opts->opt_private_group) {
	    struct group *grp = pam_modutil_getgrgid(pamh, sbuf.st_gid);

	    if (NULL == grp || NULL == grp->gr_name
		|| strcmp(luser,grp->gr_name)) {
		cp = ".rhosts writable by public group";
	    } else if (grp->gr_mem) {
		int gcount;

		/* require at most one member (luser) of this group */
		for (gcount=0; grp->gr_mem[gcount]; ++gcount) {
		    if (strcmp(grp->gr_mem[gcount], luser)) {
			gcount = -1;
			break;
		    }
		}
		if (gcount < 0) {
		    cp = ".rhosts writable by other members of group";
		}
	    }
	} else {
	    cp = ".rhosts writable by group";
	}

    } /* It is _NOT_ safe to append an else here...  Do so prior to
       * S_IWGRP check */

    /* If there were any problems, quit. */
    if (cp) {
	opts->last_error = cp;
	answer = 1;
	goto exit_function;
    }

    answer = __ivaliduser (pamh, opts, hostf, raddr, luser, ruser, rhost);

exit_function:
    /*
     * Go here to exit after the fsuid/euid has been adjusted so that
     * they are reset before we exit.
     */

#ifdef __linux__
    setfsuid(uid);
#else
    (void)seteuid(uid);
#endif

    free (fpath);

    if (hostf != NULL)
        (void) fclose(hostf);

    return answer;
}

static int
pam_ruserok (pam_handle_t *pamh,
	     struct _options *opts, const char *rhost, int superuser,
	     const char *ruser, const char *luser)
{
    struct hostent *hp;
    int answer = 1;                             /* default to failure */
    u_int32_t *addrs;
    int n, i;

    opts->last_error = (char *) 0;
    hp               = gethostbyname(rhost);         /* identify host */

    if (hp != NULL) {
	/* First of all check the address length */
        if (hp->h_length != 4) {
            pam_syslog(pamh, LOG_ALERT,
		       "pam_rhosts module can't work with non-IPv4 addresses");
            return 1;                                    /* not allowed */
        }

        /* loop though address list */
        for (n = 0; hp->h_addr_list[n]; n++);
        D(("rhosts: %d addresses", n));

        if (n) {
            addrs = calloc (n, hp->h_length);
            for (i = 0; i < n; i++)
                memcpy (addrs+i, hp->h_addr_list[i], hp->h_length);

            for (i = 0; i < n && answer; i++) {
                D(("rhosts: address %d is %04x", i, addrs[i]));
                answer = pam_iruserok(pamh, opts, addrs[i], superuser,
				      ruser, luser, rhost);
                         /* answer == 0 means success */
            }

            free (addrs);
        }
    }

    return answer;
}

/*
 * Internal function to do authentication
 */

static int _pam_auth_rhosts (pam_handle_t *pamh,
			     int flags,
			     int argc,
			     const char **argv)
{
    int retval;
    const char *luser = NULL;
    const char *ruser = NULL, *rhost = NULL;
    struct _options opts;
    int as_root = 0;

    /*
     * Look at the options and set the flags accordingly.
     */
    memset (&opts, 0, sizeof (opts));
    set_parameters (pamh, &opts, flags, argc, argv);
    /*
     * Obtain the parameters for the various items
     */
    for (;;) {                         /* abuse loop to avoid goto */

	/* get the remotehost */
	D(("getting rhost"));
	retval = pam_get_rhost(pamh, &rhost);
	(void) pam_set_item(pamh, PAM_RHOST, rhost);
	if (retval != PAM_SUCCESS) {
	    if (opts.opt_debug) {
		pam_syslog(pamh, LOG_DEBUG,
			   "could not get the remote host name");
	    }
	    break;
	}

	/* get the remote user */
	D(("getting ruser"));
	retval = pam_get_ruser(pamh, &ruser);
	(void) pam_set_item(pamh, PAM_RUSER, ruser);
	if (retval != PAM_SUCCESS) {
	    if (opts.opt_debug)
		pam_syslog(pamh, LOG_DEBUG,
			   "could not get the remote username");
	    break;
	}

	/* get the local user */
	D(("getting user"));
	retval = pam_get_user(pamh, &luser, NULL);
	if (retval != PAM_SUCCESS) {
	    if (opts.opt_debug)
		pam_syslog(pamh, LOG_DEBUG,
			   "could not determine name of local user");
	    break;
	}

	if (opts.superuser && !strcmp(opts.superuser, luser)) {
	    as_root = 1;
	}

	/* check if the luser uid == 0... --cristiang */
	if (! opts.opt_no_uid_check) {
	    struct passwd *luser_pwd;

	    luser_pwd = pam_modutil_getpwnam(pamh, luser);
	    if (luser_pwd == NULL) {
		if (opts.opt_debug)
		    pam_syslog(pamh, LOG_DEBUG,
			       "user '%s' unknown to this system", luser);
		retval = PAM_AUTH_ERR;
		break;
	    }
	    if (luser_pwd->pw_uid == 0)
		as_root = 1;
	    luser_pwd = NULL;                                   /* forget */
	}
/*
 * Validate the account information.
 */
	if (pam_ruserok (pamh, &opts, rhost, as_root, ruser, luser) != 0) {
	    if ( !opts.opt_suppress ) {
		pam_syslog(pamh, LOG_WARNING, "denied to %s@%s as %s: %s",
			 ruser, rhost, luser, (opts.last_error==NULL) ?
			 "access not allowed":opts.last_error);
	    }
	    retval = PAM_AUTH_ERR;
	} else {
	    pam_syslog(pamh, LOG_NOTICE, "allowed to %s@%s as %s",
                     ruser, rhost, luser);
	}
	break;
    }

    return retval;
}

/* --- authentication management functions --- */

PAM_EXTERN
int pam_sm_authenticate (pam_handle_t *pamh,
			 int flags,
			 int argc,
			 const char **argv)
{
    int retval;

    if (sizeof(u_int32_t) != 4) {
        pam_syslog (pamh, LOG_ALERT,
		    "pam_rhosts module can\'t work on this hardware (yet)");
        return PAM_AUTH_ERR;
    }
    sethostent(1);
    retval = _pam_auth_rhosts (pamh, flags, argc, argv);
    endhostent();
    return retval;
}

PAM_EXTERN int
pam_sm_setcred (pam_handle_t *pamh UNUSED, int flags UNUSED,
		int argc UNUSED, const char **argv UNUSED)
{
    return PAM_SUCCESS;
}

/* end of module definition */


#ifdef PAM_STATIC

/* static module data */

struct pam_module _pam_rhosts_auth_modstruct = {
    "pam_rhosts_auth",
    pam_sm_authenticate,
    pam_sm_setcred,
    NULL,
    NULL,
    NULL,
    NULL,
};

#endif