1 /* $OpenBSD: sshlogin.c,v 1.34 2019/06/28 13:35:04 deraadt Exp $ */
2 /*
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * All rights reserved
6 * This file performs some of the things login(1) normally does. We cannot
7 * easily use something like login -p -h host -f user, because there are
8 * several different logins around, and it is hard to determined what kind of
9 * login the current system has. Also, we want to be able to execute commands
10 * on a tty.
11 *
12 * As far as I am concerned, the code I have written for this software
13 * can be used freely for any purpose. Any derived versions of this
14 * software must be clearly marked as such, and if the derived work is
15 * incompatible with the protocol description in the RFC file, it must be
16 * called by a name other than "ssh" or "Secure Shell".
17 *
18 * Copyright (c) 1999 Theo de Raadt. All rights reserved.
19 * Copyright (c) 1999 Markus Friedl. All rights reserved.
20 *
21 * Redistribution and use in source and binary forms, with or without
22 * modification, are permitted provided that the following conditions
23 * are met:
24 * 1. Redistributions of source code must retain the above copyright
25 * notice, this list of conditions and the following disclaimer.
26 * 2. Redistributions in binary form must reproduce the above copyright
27 * notice, this list of conditions and the following disclaimer in the
28 * documentation and/or other materials provided with the distribution.
29 *
30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
31 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
33 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
34 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
35 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
36 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
37 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
38 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
39 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
40 */
41
42 #include "includes.h"
43
44 #include <sys/types.h>
45 #include <sys/socket.h>
46
47 #include <netinet/in.h>
48
49 #include <errno.h>
50 #include <fcntl.h>
51 #include <stdarg.h>
52 #include <stdio.h>
53 #include <string.h>
54 #include <time.h>
55 #include <unistd.h>
56 #include <limits.h>
57
58 #include "sshlogin.h"
59 #include "ssherr.h"
60 #include "loginrec.h"
61 #include "log.h"
62 #include "sshbuf.h"
63 #include "misc.h"
64 #include "servconf.h"
65
66 extern struct sshbuf *loginmsg;
67 extern ServerOptions options;
68
69 /*
70 * Returns the time when the user last logged in. Returns 0 if the
71 * information is not available. This must be called before record_login.
72 * The host the user logged in from will be returned in buf.
73 */
74 time_t
get_last_login_time(uid_t uid,const char * logname,char * buf,size_t bufsize)75 get_last_login_time(uid_t uid, const char *logname,
76 char *buf, size_t bufsize)
77 {
78 struct logininfo li;
79
80 login_get_lastlog(&li, uid);
81 strlcpy(buf, li.hostname, bufsize);
82 return (time_t)li.tv_sec;
83 }
84
85 /*
86 * Generate and store last login message. This must be done before
87 * login_login() is called and lastlog is updated.
88 */
89 static void
store_lastlog_message(const char * user,uid_t uid)90 store_lastlog_message(const char *user, uid_t uid)
91 {
92 #ifndef NO_SSH_LASTLOG
93 # ifndef CUSTOM_SYS_AUTH_GET_LASTLOGIN_MSG
94 char hostname[HOST_NAME_MAX+1] = "";
95 time_t last_login_time;
96 # endif
97 char *time_string;
98 int r;
99
100 if (!options.print_lastlog)
101 return;
102
103 # ifdef CUSTOM_SYS_AUTH_GET_LASTLOGIN_MSG
104 time_string = sys_auth_get_lastlogin_msg(user, uid);
105 if (time_string != NULL) {
106 if ((r = sshbuf_put(loginmsg,
107 time_string, strlen(time_string))) != 0)
108 fatal("%s: buffer error: %s", __func__, ssh_err(r));
109 free(time_string);
110 }
111 # else
112 last_login_time = get_last_login_time(uid, user, hostname,
113 sizeof(hostname));
114
115 if (last_login_time != 0) {
116 time_string = ctime(&last_login_time);
117 time_string[strcspn(time_string, "\n")] = '\0';
118 if (strcmp(hostname, "") == 0)
119 r = sshbuf_putf(loginmsg, "Last login: %s\r\n",
120 time_string);
121 else
122 r = sshbuf_putf(loginmsg, "Last login: %s from %s\r\n",
123 time_string, hostname);
124 if (r != 0)
125 fatal("%s: buffer error: %s", __func__, ssh_err(r));
126 }
127 # endif /* CUSTOM_SYS_AUTH_GET_LASTLOGIN_MSG */
128 #endif /* NO_SSH_LASTLOG */
129 }
130
131 /*
132 * Records that the user has logged in. I wish these parts of operating
133 * systems were more standardized.
134 */
135 void
record_login(pid_t pid,const char * tty,const char * user,uid_t uid,const char * host,struct sockaddr * addr,socklen_t addrlen)136 record_login(pid_t pid, const char *tty, const char *user, uid_t uid,
137 const char *host, struct sockaddr *addr, socklen_t addrlen)
138 {
139 struct logininfo *li;
140
141 /* save previous login details before writing new */
142 store_lastlog_message(user, uid);
143
144 li = login_alloc_entry(pid, user, host, tty);
145 login_set_addr(li, addr, addrlen);
146 login_login(li);
147 login_free_entry(li);
148 }
149
150 #ifdef LOGIN_NEEDS_UTMPX
151 void
record_utmp_only(pid_t pid,const char * ttyname,const char * user,const char * host,struct sockaddr * addr,socklen_t addrlen)152 record_utmp_only(pid_t pid, const char *ttyname, const char *user,
153 const char *host, struct sockaddr *addr, socklen_t addrlen)
154 {
155 struct logininfo *li;
156
157 li = login_alloc_entry(pid, user, host, ttyname);
158 login_set_addr(li, addr, addrlen);
159 login_utmp_only(li);
160 login_free_entry(li);
161 }
162 #endif
163
164 /* Records that the user has logged out. */
165 void
record_logout(pid_t pid,const char * tty,const char * user)166 record_logout(pid_t pid, const char *tty, const char *user)
167 {
168 struct logininfo *li;
169
170 li = login_alloc_entry(pid, user, NULL, tty);
171 login_logout(li);
172 login_free_entry(li);
173 }
174