xref: /freebsd/lib/libpam/modules/pam_lastlog/pam_lastlog.c (revision ae83180158c4c937f170e31eff311b18c0286a93)
1 /*-
2  * Copyright (c) 1980, 1987, 1988, 1991, 1993, 1994
3  *	The Regents of the University of California.  All rights reserved.
4  * Copyright (c) 2001 Mark R V Murray
5  * All rights reserved.
6  * Copyright (c) 2001 Networks Associates Technology, Inc.
7  * All rights reserved.
8  *
9  * Portions of this software were developed for the FreeBSD Project by
10  * ThinkSec AS and NAI Labs, the Security Research Division of Network
11  * Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
12  * ("CBOSS"), as part of the DARPA CHATS research program.
13  *
14  * Redistribution and use in source and binary forms, with or without
15  * modification, are permitted provided that the following conditions
16  * are met:
17  * 1. Redistributions of source code must retain the above copyright
18  *    notice, this list of conditions and the following disclaimer.
19  * 2. Redistributions in binary form must reproduce the above copyright
20  *    notice, this list of conditions and the following disclaimer in the
21  *    documentation and/or other materials provided with the distribution.
22  * 3. The name of the author may not be used to endorse or promote
23  *    products derived from this software without specific prior written
24  *    permission.
25  * 4. Neither the name of the University nor the names of its contributors
26  *    may be used to endorse or promote products derived from this software
27  *    without specific prior written permission.
28  *
29  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
30  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
31  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
32  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
33  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
34  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
35  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
36  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
37  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
38  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39  * SUCH DAMAGE.
40  */
41 
42 #include <sys/cdefs.h>
43 __FBSDID("$FreeBSD$");
44 
45 #define _BSD_SOURCE
46 
47 #include <sys/param.h>
48 
49 #include <fcntl.h>
50 #include <libutil.h>
51 #include <paths.h>
52 #include <pwd.h>
53 #include <stdio.h>
54 #include <stdlib.h>
55 #include <string.h>
56 #include <syslog.h>
57 #include <time.h>
58 #include <unistd.h>
59 #include <utmp.h>
60 
61 #define PAM_SM_SESSION
62 
63 #include <security/pam_appl.h>
64 #include <security/pam_modules.h>
65 #include <security/pam_mod_misc.h>
66 
67 PAM_EXTERN int
68 pam_sm_open_session(pam_handle_t *pamh, int flags,
69     int argc __unused, const char *argv[] __unused)
70 {
71 	struct passwd *pwd;
72 	struct utmp utmp;
73 	struct lastlog ll;
74 	const char *rhost, *user, *tty;
75 	off_t llpos;
76 	int fd, pam_err;
77 
78 	pam_err = pam_get_user(pamh, &user, NULL);
79 	if (pam_err != PAM_SUCCESS)
80 		return (pam_err);
81 	if (user == NULL || (pwd = getpwnam(user)) == NULL)
82 		return (PAM_SERVICE_ERR);
83 	PAM_LOG("Got user: %s", user);
84 
85 	pam_err = pam_get_item(pamh, PAM_RHOST, (const void **)&rhost);
86 	if (pam_err != PAM_SUCCESS)
87 		goto err;
88 	pam_err = pam_get_item(pamh, PAM_TTY, (const void **)&tty);
89 	if (pam_err != PAM_SUCCESS)
90 		goto err;
91 	if (tty == NULL) {
92 		pam_err = PAM_SERVICE_ERR;
93 		goto err;
94 	}
95 	if (strncmp(tty, _PATH_DEV, strlen(_PATH_DEV)) == 0)
96 		tty += strlen(_PATH_DEV);
97 	if (*tty == '\0')
98 		return (PAM_SERVICE_ERR);
99 
100 	fd = open(_PATH_LASTLOG, O_RDWR|O_CREAT, 0644);
101 	if (fd == -1)
102 		goto file_err;
103 
104 	/*
105 	 * Record session in lastlog(5).
106 	 */
107 	llpos = (off_t)(pwd->pw_uid * sizeof(ll));
108 	if (lseek(fd, llpos, L_SET) != llpos)
109 		goto file_err;
110 	if ((flags & PAM_SILENT) == 0) {
111 		if (read(fd, &ll, sizeof ll) == sizeof ll && ll.ll_time != 0) {
112 			if (*ll.ll_host != '\0')
113 				pam_info(pamh, "Last login: %.*s from %.*s",
114 				    24 - 5, ctime(&ll.ll_time),
115 				    (int)sizeof(ll.ll_host), ll.ll_host);
116 			else
117 				pam_info(pamh, "Last login: %.*s on %.*s",
118 				    24 - 5, ctime(&ll.ll_time),
119 				    (int)sizeof(ll.ll_line), ll.ll_line);
120 		}
121 		if (lseek(fd, llpos, L_SET) != llpos)
122 			goto file_err;
123 	}
124 
125 	bzero(&ll, sizeof(ll));
126 	time(&ll.ll_time);
127 
128 	/* note: does not need to be NUL-terminated */
129 	strncpy(ll.ll_line, tty, sizeof(ll.ll_line));
130 	if (rhost != NULL)
131 		/* note: does not need to be NUL-terminated */
132 		strncpy(ll.ll_host, rhost, sizeof(ll.ll_host));
133 
134 	if (write(fd, (char *)&ll, sizeof(ll)) != sizeof(ll) || close(fd) != 0)
135 		goto file_err;
136 
137 	PAM_LOG("Login recorded in %s", _PATH_LASTLOG);
138 
139 	/*
140 	 * Record session in utmp(5) and wtmp(5).
141 	 */
142 	bzero(&utmp, sizeof(utmp));
143 	time(&utmp.ut_time);
144 	/* note: does not need to be NUL-terminated */
145 	strncpy(utmp.ut_name, user, sizeof(utmp.ut_name));
146 	if (rhost != NULL)
147 		strncpy(utmp.ut_host, rhost, sizeof(utmp.ut_host));
148 	(void)strncpy(utmp.ut_line, tty, sizeof(utmp.ut_line));
149 	login(&utmp);
150 
151 	return (PAM_SUCCESS);
152 
153 file_err:
154 	syslog(LOG_ERR, "%s: %m", _PATH_LASTLOG);
155 	if (fd != -1)
156 		close(fd);
157 	pam_err = PAM_SYSTEM_ERR;
158 err:
159 	if (openpam_get_option(pamh, "no_fail"))
160 		return (PAM_SUCCESS);
161 	return (pam_err);
162 }
163 
164 PAM_EXTERN int
165 pam_sm_close_session(pam_handle_t *pamh __unused, int flags __unused,
166     int argc __unused, const char *argv[] __unused)
167 {
168 
169 	return (PAM_SUCCESS);
170 }
171 
172 PAM_MODULE_ENTRY("pam_lastlog");
173