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      1 /*	$NetBSD: pam_guest.c,v 1.2 2004/12/12 08:18:45 christos Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2003 Networks Associates Technology, Inc.
      5  * All rights reserved.
      6  *
      7  * Portions of this software were developed for the FreeBSD Project by
      8  * ThinkSec AS and NAI Labs, the Security Research Division of Network
      9  * Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
     10  * ("CBOSS"), as part of the DARPA CHATS research program.
     11  *
     12  * Redistribution and use in source and binary forms, with or without
     13  * modification, are permitted provided that the following conditions
     14  * are met:
     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. The name of the author may not be used to endorse or promote
     21  *    products derived from this software without specific prior written
     22  *    permission.
     23  *
     24  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
     25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     34  * SUCH DAMAGE.
     35  */
     36 
     37 #include <sys/cdefs.h>
     38 #ifdef __FreeBSD__
     39 __FBSDID("$FreeBSD: src/lib/libpam/modules/pam_guest/pam_guest.c,v 1.1 2003/05/31 16:52:58 des Exp $");
     40 #else
     41 __RCSID("$NetBSD: pam_guest.c,v 1.2 2004/12/12 08:18:45 christos Exp $");
     42 #endif
     43 
     44 #include <string.h>
     45 
     46 #define PAM_SM_AUTH
     47 
     48 #include <security/pam_appl.h>
     49 #include <security/pam_modules.h>
     50 #include <security/openpam.h>
     51 
     52 #define DEFAULT_GUESTS	"guest"
     53 
     54 static int
     55 lookup(const char *str, const char *list)
     56 {
     57 	const char *next;
     58 	size_t len;
     59 
     60 	len = strlen(str);
     61 	while (*list != '\0') {
     62 		while (*list == ',')
     63 			++list;
     64 		if ((next = strchr(list, ',')) == NULL)
     65 			next = strchr(list, '\0');
     66 		if (next - list == (ptrdiff_t)len &&
     67 		    strncmp(list, str, len) == 0)
     68 			return (1);
     69 		list = next;
     70 	}
     71 	return (0);
     72 }
     73 
     74 PAM_EXTERN int
     75 pam_sm_authenticate(pam_handle_t *pamh, int flags __unused,
     76     int argc __unused, const char *argv[] __unused)
     77 {
     78 	const char *authtok, *guests, *user;
     79 	int err, is_guest;
     80 
     81 	/* get target account */
     82 	if (pam_get_user(pamh, &user, NULL) != PAM_SUCCESS || user == NULL)
     83 		return (PAM_AUTH_ERR);
     84 
     85 	/* get list of guest logins */
     86 	if ((guests = openpam_get_option(pamh, "guests")) == NULL)
     87 		guests = DEFAULT_GUESTS;
     88 
     89 	/* check if the target account is on the list */
     90 	is_guest = lookup(user, guests);
     91 
     92 	/* check password */
     93 	if (!openpam_get_option(pamh, "nopass")) {
     94 		err = pam_get_authtok(pamh, PAM_AUTHTOK, &authtok, NULL);
     95 		if (err != PAM_SUCCESS)
     96 			return (err);
     97 		if (openpam_get_option(pamh, "pass_is_user") &&
     98 		    strcmp(user, authtok) != 0)
     99 			return (PAM_AUTH_ERR);
    100 		if (openpam_get_option(pamh, "pass_as_ruser"))
    101 			pam_set_item(pamh, PAM_RUSER, authtok);
    102 	}
    103 
    104 	/* done */
    105 	if (is_guest) {
    106 		pam_setenv(pamh, "GUEST", user, 1);
    107 		return (PAM_SUCCESS);
    108 	}
    109 	return (PAM_AUTH_ERR);
    110 }
    111 
    112 PAM_EXTERN int
    113 pam_sm_setcred(pam_handle_t * pamh __unused, int flags __unused,
    114     int argc __unused, const char *argv[] __unused)
    115 {
    116 
    117 	return (PAM_SUCCESS);
    118 }
    119 
    120 PAM_MODULE_ENTRY("pam_guest");
    121