xref: /illumos-gate/usr/src/lib/pam_modules/unix_session/unix_session.c (revision e3ae4b35c024af1196582063ecee3ab79367227d)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2005 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  * Copyright 2016 Toomas Soome <tsoome@me.com>
26  */
27 
28 #include <strings.h>
29 #include <sys/types.h>
30 #include <sys/wait.h>
31 #include <sys/stat.h>
32 #include <fcntl.h>
33 #include <stdlib.h>
34 #include <security/pam_appl.h>
35 #include <security/pam_modules.h>
36 #include <security/pam_impl.h>
37 #include <syslog.h>
38 #include <pwd.h>
39 #include <shadow.h>
40 #include <lastlog.h>
41 #include <ctype.h>
42 #include <unistd.h>
43 #include <stdlib.h>
44 #include <stdio.h>
45 #include <libintl.h>
46 #include <signal.h>
47 #include <thread.h>
48 #include <synch.h>
49 #include <errno.h>
50 #include <time.h>
51 #include <string.h>
52 #include <crypt.h>
53 #include <assert.h>
54 #include <nss_dbdefs.h>
55 
56 #define	LASTLOG		"/var/adm/lastlog"
57 
58 /*
59  * pam_sm_close_session	- Terminate a PAM authenticated session
60  */
61 /*ARGSUSED*/
62 int
63 pam_sm_close_session(pam_handle_t *pamh, int flags, int argc,
64     const char **argv)
65 {
66 	int	i;
67 	int	debug = 0;
68 
69 	for (i = 0; i < argc; i++) {
70 		if (strcasecmp(argv[i], "debug") == 0)
71 			debug = 1;
72 		else if (strcasecmp(argv[i], "nowarn") != 0)
73 			syslog(LOG_ERR, "illegal option %s", argv[i]);
74 	}
75 
76 	if (debug)
77 		syslog(LOG_DEBUG,
78 		    "pam_unix_session: inside pam_sm_close_session()");
79 
80 	return (PAM_SUCCESS);
81 }
82 
83 /*ARGSUSED*/
84 int
85 pam_sm_open_session(pam_handle_t *pamh, int flags, int argc,
86     const char **argv)
87 {
88 	int	error;
89 	char    *ttyn, *rhost, *user;
90 	int	fdl;
91 	struct lastlog  newll;
92 	struct passwd pwd;
93 	char    buffer[NSS_BUFLEN_PASSWD];
94 	int	i;
95 	int	debug = 0;
96 	offset_t	offset;
97 	time_t  cur_time;
98 
99 	for (i = 0; i < argc; i++) {
100 		if (strcasecmp(argv[i], "debug") == 0)
101 			debug = 1;
102 		else if (strcasecmp(argv[i], "nowarn") == 0)
103 			flags = flags | PAM_SILENT;
104 		else
105 			syslog(LOG_ERR, "illegal option %s", argv[i]);
106 	}
107 
108 	if (debug)
109 		syslog(LOG_DEBUG,
110 		    "pam_unix_session: inside pam_sm_open_session()");
111 
112 	if ((error = pam_get_item(pamh, PAM_TTY, (void **)&ttyn))
113 	    != PAM_SUCCESS ||
114 	    (error = pam_get_item(pamh, PAM_USER, (void **)&user))
115 	    != PAM_SUCCESS ||
116 	    (error = pam_get_item(pamh, PAM_RHOST, (void **)&rhost))
117 	    != PAM_SUCCESS) {
118 		return (error);
119 	}
120 
121 	if (user == NULL || *user == '\0')
122 		return (PAM_USER_UNKNOWN);
123 
124 	/* report error if ttyn not set */
125 	if (ttyn == NULL)
126 		return (PAM_SESSION_ERR);
127 
128 	if (getpwnam_r(user, &pwd, buffer, sizeof (buffer)) == NULL) {
129 		return (PAM_USER_UNKNOWN);
130 	}
131 
132 	if ((fdl = open(LASTLOG, O_RDWR|O_CREAT|O_DSYNC, 0444)) >= 0) {
133 		/*
134 		 * The value of lastlog is read by the UNIX
135 		 * account management module
136 		 */
137 		offset = (offset_t)pwd.pw_uid *
138 		    (offset_t)sizeof (struct lastlog);
139 
140 		if (llseek(fdl, offset, SEEK_SET) != offset) {
141 			syslog(LOG_ERR,
142 			    "pam_unix_session: Can't update lastlog: uid %d "
143 			    "too large", pwd.pw_uid);
144 			(void) close(fdl);
145 			return (PAM_SUCCESS);
146 		}
147 		/*
148 		 * use time32_t in case of _LP64
149 		 * since it's written in lastlog.h
150 		 */
151 		(void) time(&cur_time);
152 
153 		bzero((char *)&newll, sizeof (struct lastlog));
154 #ifdef _LP64
155 		newll.ll_time = (time32_t)cur_time;
156 #else
157 		newll.ll_time = cur_time;
158 #endif
159 		if ((strncmp(ttyn, "/dev/", 5) == 0)) {
160 			(void) strlcpy(newll.ll_line,
161 			    (ttyn + sizeof ("/dev/")-1),
162 			    sizeof (newll.ll_line));
163 		} else {
164 			(void) strlcpy(newll.ll_line, ttyn,
165 			    sizeof (newll.ll_line));
166 		}
167 		if (rhost != NULL) {
168 			(void) strlcpy(newll.ll_host, rhost,
169 			    sizeof (newll.ll_host));
170 		}
171 		if (debug) {
172 			char	buf[26];
173 
174 			(void) ctime_r((const time_t *)&cur_time, buf,
175 			    sizeof (buf));
176 			buf[24] = '\000';
177 			syslog(LOG_DEBUG, "pam_unix_session: "
178 			    "user = %s, time = %s, tty = %s, host = %s.",
179 			    user, buf, newll.ll_line, newll.ll_host);
180 		}
181 		if (write(fdl, (char *)&newll, sizeof (newll))
182 		    != sizeof (newll))
183 			syslog(LOG_ERR, "pam_unix_session: Can't write "
184 			    "lastlog: uid %d: %m", pwd.pw_uid);
185 		if (close(fdl) != 0)
186 			syslog(LOG_ERR, "pam_unix_session: Can't close "
187 			    "lastlog: uid %d: %m", pwd.pw_uid);
188 	}
189 	return (PAM_SUCCESS);
190 }
191