1 /*----------------------------------------------------------------------
2 * Modified for Linux-PAM by Al Longyear <longyear@netcom.com> 96/5/5
3 * Modifications, Cristian Gafton 97/2/8
4 * Modifications, Peter Allgeyer 97/3
5 * Modifications (netgroups and fixes), Nicolai Langfeldt 97/3/21
6 * Security fix: 97/10/2 - gethostbyname called repeatedly without care
7 * Modification (added privategroup option) Andrew <morgan@transmeta.com>
8 *----------------------------------------------------------------------
9 * Copyright (c) 1983, 1993, 1994
10 * The Regents of the University of California. All rights reserved.
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. All advertising materials mentioning features or use of this software
21 * must display the following acknowledgement:
22 * This product includes software developed by the University of
23 * California, Berkeley and its contributors.
24 * 4. Neither the name of the University nor the names of its contributors
25 * may be used to endorse or promote products derived from this software
26 * without specific prior written permission.
28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39 * $FreeBSD: src/contrib/libpam/modules/pam_rhosts/pam_rhosts_auth.c,v 1.3.2.2 2001/06/11 15:28:24 markm Exp $
40 * $DragonFly: src/contrib/libpam/modules/pam_rhosts/Attic/pam_rhosts_auth.c,v 1.2 2003/06/17 04:24:03 dillon Exp $
45 #define USER_RHOSTS_FILE "/.rhosts" /* prefixed by user's home dir */
52 #include <sys/fsuid.h>
53 #endif /* NEED_FSUID_H */
55 #include <sys/types.h>
60 #include <sys/param.h>
61 #include <sys/socket.h>
62 #include <netinet/in.h>
63 #include <netdb.h> /* This is supposed(?) to contain the following */
64 int innetgr(const char *, const char *, const char *,const char *);
69 #include <arpa/inet.h>
80 # include <linux/sockios.h>
83 # include <sys/fsuid.h>
84 # endif /* __USE_MISC */
90 #include <sys/signal.h>
94 #define _PATH_HEQUIV "/etc/hosts.equiv"
95 #endif /* _PATH_HEQUIV */
97 #define PAM_SM_AUTH /* only defines this management group */
99 #include <security/pam_modules.h>
100 #include <security/_pam_macros.h>
102 /* to the best of my knowledge, all modern UNIX boxes have 32 bit integers */
103 #define U32 unsigned int
107 * Options for this module
111 int opt_no_hosts_equiv;
112 int opt_hosts_equiv_rootok;
116 int opt_disallow_null_authtok;
120 int opt_private_group;
121 int opt_no_uid_check;
122 const char *superuser;
123 const char *last_error;
127 static void _pam_log(int err, const char *format, ...)
131 va_start(args, format);
132 openlog("pam_rhosts_auth", LOG_CONS|LOG_PID, LOG_AUTH);
133 vsyslog(err, format, args);
138 static void set_option (struct _options *opts, const char *arg)
140 if (strcmp(arg, "no_hosts_equiv") == 0) {
141 opts->opt_no_hosts_equiv = 1;
145 if (strcmp(arg, "hosts_equiv_rootok") == 0) {
146 opts->opt_hosts_equiv_rootok = 1;
150 if (strcmp(arg, "no_rhosts") == 0) {
151 opts->opt_no_rhosts = 1;
155 if (strcmp(arg, "debug") == 0) {
156 D(("debugging enabled"));
161 if (strcmp(arg, "no_warn") == 0) {
162 opts->opt_nowarn = 1;
166 if (strcmp(arg, "promiscuous") == 0) {
167 opts->opt_promiscuous = 1; /* used to permit '+' in ...hosts file */
171 if (strcmp(arg, "suppress") == 0) {
172 opts->opt_suppress = 1; /* used to suppress failure warning message */
176 if (strcmp(arg, "privategroup") == 0) {
177 opts->opt_private_group = 1; /* used to permit group write on .rhosts
178 file if group has same name as owner */
182 if (strcmp(arg, "no_uid_check") == 0) {
183 opts->opt_no_uid_check = 1; /* NIS optimization */
187 if (strcmp(arg, "superuser=") == 0) {
188 opts->superuser = arg+sizeof("superuser=")-1;
192 * All other options are ignored at the present time.
194 _pam_log(LOG_WARNING, "unrecognized option '%s'", arg);
197 static void set_parameters (struct _options *opts, int flags,
198 int argc, const char **argv)
200 opts->opt_silent = flags & PAM_SILENT;
201 opts->opt_disallow_null_authtok = flags & PAM_DISALLOW_NULL_AUTHTOK;
204 set_option (opts, *argv);
210 * Obtain the name of the remote host. Currently, this is simply by
211 * requesting the contents of the PAM_RHOST item.
214 static int pam_get_rhost(pam_handle_t *pamh, const char **rhost
215 , const char *prompt)
220 retval = pam_get_item (pamh, PAM_RHOST, (const void **)¤t);
221 if (retval != PAM_SUCCESS)
224 if (current == NULL) {
229 return retval; /* pass on any error from conversation */
233 * Obtain the name of the remote user. Currently, this is simply by
234 * requesting the contents of the PAM_RUSER item.
237 static int pam_get_ruser(pam_handle_t *pamh, const char **ruser
238 , const char *prompt)
243 retval = pam_get_item (pamh, PAM_RUSER, (const void **)¤t);
244 if (retval != PAM_SUCCESS)
247 if (current == NULL) {
252 return retval; /* pass on any error from conversation */
256 * Returns 1 if positive match, 0 if no match, -1 if negative match.
260 __icheckhost (pam_handle_t *pamh, struct _options *opts, U32 raddr
261 , register char *lhost, const char *rhost)
265 int negate=1; /* Multiply return with this to get -1 instead of 1 */
268 /* Check nis netgroup. We assume that pam has done all needed
269 paranoia checking before we are handed the rhost */
270 if (strncmp("+@",lhost,2) == 0)
271 return(innetgr(&lhost[2],rhost,NULL,NULL));
273 if (strncmp("-@",lhost,2) == 0)
274 return(-innetgr(&lhost[2],rhost,NULL,NULL));
277 if (strncmp("-",lhost,1) == 0) {
280 } else if (strcmp("+",lhost) == 0) {
281 (void) pam_get_item(pamh, PAM_USER, (const void **)&user);
282 D(("user %s has a `+' host entry", user));
283 if (opts->opt_promiscuous)
284 return (1); /* asking for trouble, but ok.. */
285 /* If not promiscuous: handle as negative */
289 /* Try for raw ip address first. */
290 if (isdigit(*lhost) && (long)(laddr = inet_addr(lhost)) != -1)
291 return (negate*(! (raddr ^ laddr)));
293 /* Better be a hostname. */
294 hp = gethostbyname(lhost);
298 /* Spin through ip addresses. */
299 for (pp = hp->h_addr_list; *pp; ++pp)
300 if (!memcmp (&raddr, *pp, sizeof (U32)))
307 /* Returns 1 on positive match, 0 on no match, -1 on negative match */
309 static int __icheckuser(pam_handle_t *pamh, struct _options *opts
310 , const char *luser, const char *ruser
314 luser is user entry from .rhosts/hosts.equiv file
315 ruser is user id on remote host
316 rhost is the remote host name
321 if (strncmp("+@",luser,2) == 0)
322 return (innetgr(&luser[2],NULL,ruser,NULL));
324 if (strncmp("-@",luser,2) == 0)
325 return (-innetgr(&luser[2],NULL,ruser,NULL));
328 if (strncmp("-",luser,1) == 0)
329 return(-(strcmp(&luser[1],ruser) == 0));
332 if (strcmp("+",luser) == 0) {
333 (void) pam_get_item(pamh, PAM_USER, (const void **)&user);
334 _pam_log(LOG_WARNING, "user %s has a `+' user entry", user);
335 if (opts->opt_promiscuous)
337 /* If not promiscuous we handle it as a negative match */
341 /* simple string match */
342 return (strcmp(ruser, luser) == 0);
346 * Returns 1 for blank lines (or only comment lines) and 0 otherwise
349 static int __isempty(char *p)
351 while (*p && isspace(*p)) {
355 return (*p == '\0' || *p == '#') ? 1:0 ;
359 * Returns 0 if positive match, 1 if _not_ ok.
363 __ivaliduser (pam_handle_t *pamh, struct _options *opts,
364 FILE *hostf, U32 raddr,
365 const char *luser, const char *ruser, const char *rhost)
367 register const char *user;
370 char buf[MAXHOSTNAMELEN + 128]; /* host + login */
372 buf[sizeof (buf)-1] = '\0'; /* terminate line */
374 while (fgets(buf, sizeof(buf), hostf) != NULL) { /* hostf file line */
375 p = buf; /* from beginning of file.. */
377 /* Skip empty or comment lines */
382 /* Skip lines that are too long. */
383 if (strchr(p, '\n') == NULL) {
384 int ch = getc(hostf);
386 while (ch != '\n' && ch != EOF)
392 * If there is a hostname at the start of the line. Set it to
393 * lower case. A leading ' ' or '\t' indicates no hostname
396 for (;*p && !isspace(*p); ++p) {
401 * next we want to find the permitted name for the remote user
404 if (*p == ' ' || *p == '\t') {
406 /* <nul> terminate hostname and skip spaces */
407 for (*p++='\0'; *p && isspace(*p); ++p);
409 user = p; /* this is the user's name */
410 while (*p && !isspace(*p))
411 ++p; /* find end of user's name */
415 *p = '\0'; /* <nul> terminate username (+host?) */
417 /* buf -> host(?) ; user -> username(?) */
419 /* First check host part */
420 hcheck=__icheckhost(pamh, opts, raddr, buf, rhost);
426 /* Then check user part */
430 ucheck=__icheckuser(pamh, opts, user, ruser, rhost);
432 /* Positive 'host user' match? */
436 /* Negative 'host -user' match? */
440 /* Neither, go on looking for match */
448 * New .rhosts strategy: We are passed an ip address. We spin through
449 * hosts.equiv and .rhosts looking for a match. When the .rhosts only
450 * has ip addresses, we don't have to trust a nameserver. When it
451 * contains hostnames, we spin through the list of addresses the nameserver
452 * gives us and look for a match.
454 * Returns 0 if ok, -1 if not ok.
458 pam_iruserok(pam_handle_t *pamh,
459 struct _options *opts, U32 raddr, int superuser,
460 const char *ruser, const char *luser, const char *rhost)
468 char pbuf[MAXPATHLEN]; /* potential buffer overrun */
470 if ((!superuser||opts->opt_hosts_equiv_rootok) && !opts->opt_no_hosts_equiv ) {
472 /* try to open system hosts.equiv file */
473 hostf = fopen (_PATH_HEQUIV, "r");
475 answer = __ivaliduser(pamh, opts, hostf, raddr, luser
477 (void) fclose(hostf);
479 return 0; /* remote host is equivalent to localhost */
481 No hosts.equiv file on system.
485 if ( opts->opt_no_rhosts )
489 * Identify user's local .rhosts file
492 pwd = getpwnam(luser);
495 * luser is assumed to be valid because of an earlier check for uid = 0
496 * we don't log this error twice. However, this shouldn't happen !
502 /* check for buffer overrun */
503 if (strlen(pwd->pw_dir) + sizeof(USER_RHOSTS_FILE) + 2 >= MAXPATHLEN) {
505 _pam_log(LOG_DEBUG,"home directory for `%s' is too long", luser);
506 return 1; /* to dangerous to try */
509 (void) strcpy(pbuf, pwd->pw_dir);
510 (void) strcat(pbuf, USER_RHOSTS_FILE);
513 * Change effective uid while _reading_ .rhosts. (not just
514 * opening). If root and reading an NFS mounted file system,
515 * can't read files that are 0600 as .rhosts files should be.
518 /* We are root, this will not fail */
520 /* If we are on linux the better way is setfsuid */
521 uid = setfsuid(pwd->pw_uid);
522 hostf = fopen(pbuf, "r");
525 (void) seteuid(pwd->pw_uid);
526 hostf = fopen(pbuf, "r");
531 _pam_log(LOG_DEBUG,"Could not open %s file",pbuf);
537 * If not a regular file, or is owned by someone other than
538 * user or root or if writeable by anyone but the owner, quit.
542 if (lstat(pbuf, &sbuf) < 0 || !S_ISREG(sbuf.st_mode))
543 cp = ".rhosts not regular file";
544 else if (fstat(fileno(hostf), &sbuf) < 0)
545 cp = ".rhosts fstat failed";
546 else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid)
547 cp = "bad .rhosts owner";
548 else if (sbuf.st_mode & S_IWOTH)
549 cp = ".rhosts writable by other!";
550 else if (sbuf.st_mode & S_IWGRP) {
552 /* private group caveat */
553 if (opts->opt_private_group) {
554 struct group *grp = getgrgid(sbuf.st_gid);
556 if (NULL == grp || NULL == grp->gr_name
557 || strcmp(luser,grp->gr_name)) {
558 cp = ".rhosts writable by public group";
559 } else if (grp->gr_mem) {
562 /* require at most one member (luser) of this group */
563 for (gcount=0; grp->gr_mem[gcount]; ++gcount) {
564 if (strcmp(grp->gr_mem[gcount], luser)) {
570 cp = ".rhosts writable by other members of group";
574 cp = ".rhosts writable by group";
577 } /* It is _NOT_ safe to append an else here... Do so prior to
580 /* If there were any problems, quit. */
582 opts->last_error = cp;
587 answer = __ivaliduser (pamh, opts, hostf, raddr, luser, ruser, rhost);
591 * Go here to exit after the fsuid/euid has been adjusted so that
592 * they are reset before we exit.
602 (void) fclose(hostf);
608 pam_ruserok (pam_handle_t *pamh,
609 struct _options *opts, const char *rhost, int superuser,
610 const char *ruser, const char *luser)
613 int answer = 1; /* default to failure */
617 opts->last_error = (char *) 0;
618 hp = gethostbyname(rhost); /* identify host */
621 /* First of all check the address length */
622 if (hp->h_length != 4) {
623 _pam_log(LOG_ALERT, "pam_rhosts module can't work with not IPv4 "
625 return 1; /* not allowed */
628 /* loop though address list */
629 for (n = 0; hp->h_addr_list[n]; n++);
630 D(("rhosts: %d addresses", n));
633 addrs = calloc (n, hp->h_length);
634 for (i = 0; i < n; i++)
635 memcpy (addrs+i, hp->h_addr_list[i], hp->h_length);
637 for (i = 0; i < n && answer; i++) {
638 D(("rhosts: address %d is %04x", i, addrs[i]));
639 answer = pam_iruserok(pamh, opts, addrs[i], superuser,
640 ruser, luser, rhost);
641 /* answer == 0 means success */
652 * Internal function to do authentication
655 static int _pam_auth_rhosts (pam_handle_t *pamh,
662 const char *ruser,*rhost;
663 struct _options opts;
666 * Look at the options and set the flags accordingly.
668 memset (&opts, 0, sizeof (opts));
669 set_parameters (&opts, flags, argc, argv);
671 * Obtain the parameters for the various items
673 for (;;) { /* abuse loop to avoid goto */
675 /* get the remotehost */
676 retval = pam_get_rhost(pamh, &rhost, NULL);
677 (void) pam_set_item(pamh, PAM_RHOST, rhost);
678 if (retval != PAM_SUCCESS) {
679 if (opts.opt_debug) {
680 _pam_log(LOG_DEBUG, "could not get the remote host name");
685 /* get the remote user */
686 retval = pam_get_ruser(pamh, &ruser, NULL);
687 (void) pam_set_item(pamh, PAM_RUSER, ruser);
688 if (retval != PAM_SUCCESS) {
690 _pam_log(LOG_DEBUG, "could not get the remote username");
694 /* get the local user */
695 retval = pam_get_user(pamh, &luser, NULL);
697 if (retval != PAM_SUCCESS) {
699 _pam_log(LOG_DEBUG, "could not determine name of local user");
703 if (opts.superuser && !strcmp(opts.superuser, luser)) {
707 /* check if the luser uid == 0... --cristiang */
708 if (! opts.opt_no_uid_check) {
709 struct passwd *luser_pwd;
711 luser_pwd = getpwnam(luser);
712 if (luser_pwd == NULL) {
714 _pam_log(LOG_DEBUG, "user '%s' unknown to this system",
716 retval = PAM_AUTH_ERR;
719 if (luser_pwd->pw_uid == 0)
721 luser_pwd = NULL; /* forget */
724 * Validate the account information.
726 if (pam_ruserok (pamh, &opts, rhost, as_root, ruser, luser) != 0) {
727 if ( !opts.opt_suppress ) {
728 _pam_log(LOG_WARNING, "denied to %s@%s as %s: %s",
729 ruser, rhost, luser, (opts.last_error==NULL) ?
730 "access not allowed":opts.last_error);
732 retval = PAM_AUTH_ERR;
734 _pam_log(LOG_NOTICE, "allowed to %s@%s as %s",
735 ruser, rhost, luser);
743 /* --- authentication management functions --- */
746 int pam_sm_authenticate (pam_handle_t *pamh,
753 if (sizeof(U32) != 4) {
754 _pam_log (LOG_ALERT, "pam_rhosts module can\'t work on this hardware "
759 retval = _pam_auth_rhosts (pamh, flags, argc, argv);
765 int pam_sm_setcred(pam_handle_t *pamh,int flags,int argc,
771 /* end of module definition */
776 /* static module data */
778 struct pam_module _pam_rhosts_auth_modstruct = {