1/* $OpenBSD: sshlogin.c,v 1.33 2018/07/09 21:26:02 markus 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
66extern struct sshbuf *loginmsg;
67extern 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 */
74time_t
75get_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 */
89static void
90store_lastlog_message(const char *user, uid_t uid)
91{
92#ifndef NO_SSH_LASTLOG
93	char *time_string, hostname[HOST_NAME_MAX+1] = "";
94	time_t last_login_time;
95	int r;
96
97	if (!options.print_lastlog)
98		return;
99
100# ifdef CUSTOM_SYS_AUTH_GET_LASTLOGIN_MSG
101	time_string = sys_auth_get_lastlogin_msg(user, uid);
102	if (time_string != NULL) {
103		if ((r = sshbuf_put(loginmsg,
104		    time_string, strlen(time_string))) != 0)
105			fatal("%s: buffer error: %s", __func__, ssh_err(r));
106		free(time_string);
107	}
108# else
109	last_login_time = get_last_login_time(uid, user, hostname,
110	    sizeof(hostname));
111
112	if (last_login_time != 0) {
113		time_string = ctime(&last_login_time);
114		time_string[strcspn(time_string, "\n")] = '\0';
115		if (strcmp(hostname, "") == 0)
116			r = sshbuf_putf(loginmsg, "Last login: %s\r\n",
117			    time_string);
118		else
119			r = sshbuf_putf(loginmsg, "Last login: %s from %s\r\n",
120			    time_string, hostname);
121		if (r != 0)
122			fatal("%s: buffer error: %s", __func__, ssh_err(r));
123	}
124# endif /* CUSTOM_SYS_AUTH_GET_LASTLOGIN_MSG */
125#endif /* NO_SSH_LASTLOG */
126}
127
128/*
129 * Records that the user has logged in.  I wish these parts of operating
130 * systems were more standardized.
131 */
132void
133record_login(pid_t pid, const char *tty, const char *user, uid_t uid,
134    const char *host, struct sockaddr *addr, socklen_t addrlen)
135{
136	struct logininfo *li;
137
138	/* save previous login details before writing new */
139	store_lastlog_message(user, uid);
140
141	li = login_alloc_entry(pid, user, host, tty);
142	login_set_addr(li, addr, addrlen);
143	login_login(li);
144	login_free_entry(li);
145}
146
147#ifdef LOGIN_NEEDS_UTMPX
148void
149record_utmp_only(pid_t pid, const char *ttyname, const char *user,
150		 const char *host, struct sockaddr *addr, socklen_t addrlen)
151{
152	struct logininfo *li;
153
154	li = login_alloc_entry(pid, user, host, ttyname);
155	login_set_addr(li, addr, addrlen);
156	login_utmp_only(li);
157	login_free_entry(li);
158}
159#endif
160
161/* Records that the user has logged out. */
162void
163record_logout(pid_t pid, const char *tty, const char *user)
164{
165	struct logininfo *li;
166
167	li = login_alloc_entry(pid, user, NULL, tty);
168	login_logout(li);
169	login_free_entry(li);
170}
171