xref: /freebsd/lib/libpam/modules/pam_lastlog/pam_lastlog.c (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
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  * Copyright (c) 2004 Joe R. Doupnik
9  * All rights reserved.
10  *
11  * Portions of this software were developed for the FreeBSD Project by
12  * ThinkSec AS and NAI Labs, the Security Research Division of Network
13  * Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
14  * ("CBOSS"), as part of the DARPA CHATS research program.
15  *
16  * Redistribution and use in source and binary forms, with or without
17  * modification, are permitted provided that the following conditions
18  * are met:
19  * 1. Redistributions of source code must retain the above copyright
20  *    notice, this list of conditions and the following disclaimer.
21  * 2. Redistributions in binary form must reproduce the above copyright
22  *    notice, this list of conditions and the following disclaimer in the
23  *    documentation and/or other materials provided with the distribution.
24  * 3. The name of the author may not be used to endorse or promote
25  *    products derived from this software without specific prior written
26  *    permission.
27  * 4. Neither the name of the University nor the names of its contributors
28  *    may be used to endorse or promote products derived from this software
29  *    without specific prior written permission.
30  *
31  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
32  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
33  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
34  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
35  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
39  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
40  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
41  * SUCH DAMAGE.
42  */
43 
44 #include <sys/cdefs.h>
45 __FBSDID("$FreeBSD$");
46 
47 #define _BSD_SOURCE
48 
49 #include <sys/param.h>
50 
51 #include <fcntl.h>
52 #include <libutil.h>
53 #include <paths.h>
54 #include <pwd.h>
55 #include <stdio.h>
56 #include <stdlib.h>
57 #include <string.h>
58 #include <syslog.h>
59 #include <time.h>
60 #include <unistd.h>
61 #include <utmp.h>
62 
63 #define PAM_SM_SESSION
64 
65 #include <security/pam_appl.h>
66 #include <security/pam_modules.h>
67 #include <security/pam_mod_misc.h>
68 
69 PAM_EXTERN int
70 pam_sm_open_session(pam_handle_t *pamh, int flags,
71     int argc __unused, const char *argv[] __unused)
72 {
73 	struct passwd *pwd;
74 	struct utmp utmp;
75 	struct lastlog ll;
76 	time_t t;
77 	const char *user;
78 	const void *rhost, *tty;
79 	off_t llpos;
80 	int fd, pam_err;
81 
82 	pam_err = pam_get_user(pamh, &user, NULL);
83 	if (pam_err != PAM_SUCCESS)
84 		return (pam_err);
85 	if (user == NULL || (pwd = getpwnam(user)) == NULL)
86 		return (PAM_SERVICE_ERR);
87 	PAM_LOG("Got user: %s", user);
88 
89 	pam_err = pam_get_item(pamh, PAM_RHOST, &rhost);
90 	if (pam_err != PAM_SUCCESS) {
91 		PAM_LOG("No PAM_RHOST");
92 		goto err;
93 	}
94 	pam_err = pam_get_item(pamh, PAM_TTY, &tty);
95 	if (pam_err != PAM_SUCCESS) {
96 		PAM_LOG("No PAM_TTY");
97 		goto err;
98 	}
99 	if (tty == NULL) {
100 		PAM_LOG("No PAM_TTY");
101 		pam_err = PAM_SERVICE_ERR;
102 		goto err;
103 	}
104 	if (strncmp(tty, _PATH_DEV, strlen(_PATH_DEV)) == 0)
105 		tty = (const char *)tty + strlen(_PATH_DEV);
106 	if (*(const char *)tty == '\0')
107 		return (PAM_SERVICE_ERR);
108 
109 	fd = open(_PATH_LASTLOG, O_RDWR|O_CREAT, 0644);
110 	if (fd == -1) {
111 		PAM_LOG("Failed to open %s", _PATH_LASTLOG);
112 		goto file_err;
113 	}
114 
115 	/*
116 	 * Record session in lastlog(5).
117 	 */
118 	llpos = (off_t)(pwd->pw_uid * sizeof(ll));
119 	if (lseek(fd, llpos, L_SET) != llpos)
120 		goto file_err;
121 	if ((flags & PAM_SILENT) == 0) {
122 		if (read(fd, &ll, sizeof ll) == sizeof ll && ll.ll_time != 0) {
123 			t = ll.ll_time;
124 			if (*ll.ll_host != '\0')
125 				pam_info(pamh, "Last login: %.*s from %.*s",
126 				    24 - 5, ctime(&t),
127 				    (int)sizeof(ll.ll_host), ll.ll_host);
128 			else
129 				pam_info(pamh, "Last login: %.*s on %.*s",
130 				    24 - 5, ctime(&t),
131 				    (int)sizeof(ll.ll_line), ll.ll_line);
132 		}
133 		if (lseek(fd, llpos, L_SET) != llpos)
134 			goto file_err;
135 	}
136 
137 	bzero(&ll, sizeof(ll));
138 	ll.ll_time = time(NULL);
139 
140 	/* note: does not need to be NUL-terminated */
141 	strncpy(ll.ll_line, tty, sizeof(ll.ll_line));
142 	if (rhost != NULL && *(const char *)rhost != '\0')
143 		/* note: does not need to be NUL-terminated */
144 		strncpy(ll.ll_host, rhost, sizeof(ll.ll_host));
145 
146 	if (write(fd, (char *)&ll, sizeof(ll)) != sizeof(ll) || close(fd) != 0)
147 		goto file_err;
148 
149 	PAM_LOG("Login recorded in %s", _PATH_LASTLOG);
150 
151 	/*
152 	 * Record session in utmp(5) and wtmp(5).
153 	 */
154 	bzero(&utmp, sizeof(utmp));
155 	utmp.ut_time = time(NULL);
156 	/* note: does not need to be NUL-terminated */
157 	strncpy(utmp.ut_name, user, sizeof(utmp.ut_name));
158 	if (rhost != NULL && *(const char *)rhost != '\0')
159 		strncpy(utmp.ut_host, rhost, sizeof(utmp.ut_host));
160 	(void)strncpy(utmp.ut_line, tty, sizeof(utmp.ut_line));
161 	login(&utmp);
162 
163 	return (PAM_SUCCESS);
164 
165 file_err:
166 	syslog(LOG_ERR, "%s: %m", _PATH_LASTLOG);
167 	if (fd != -1)
168 		close(fd);
169 	pam_err = PAM_SYSTEM_ERR;
170 err:
171 	if (openpam_get_option(pamh, "no_fail"))
172 		return (PAM_SUCCESS);
173 	return (pam_err);
174 }
175 
176 PAM_EXTERN int
177 pam_sm_close_session(pam_handle_t *pamh __unused, int flags __unused,
178     int argc __unused, const char *argv[] __unused)
179 {
180 	const void *tty;
181 	int pam_err;
182 
183 	pam_err = pam_get_item(pamh, PAM_TTY, (const void **)&tty);
184 	if (pam_err != PAM_SUCCESS)
185 		goto err;
186 	if (strncmp(tty, _PATH_DEV, strlen(_PATH_DEV)) == 0)
187 		tty = (const char *)tty + strlen(_PATH_DEV);
188 	if (*(const char *)tty == '\0')
189 		return (PAM_SERVICE_ERR);
190 	if (logout(tty) != 1)
191 		syslog(LOG_ERR, "%s(): no utmp record for %s",
192 		    __func__, (const char *)tty);
193 	logwtmp(tty, "", "");
194 	return (PAM_SUCCESS);
195 
196  err:
197 	if (openpam_get_option(pamh, "no_fail"))
198 		return (PAM_SUCCESS);
199 	return (pam_err);
200 }
201 
202 PAM_MODULE_ENTRY("pam_lastlog");
203