1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
|
/* $NetBSD: sshlogin.c,v 1.13 2021/03/05 17:47:16 christos Exp $ */
/* $OpenBSD: sshlogin.c,v 1.35 2020/10/18 11:32:02 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
* This file performs some of the things login(1) normally does. We cannot
* easily use something like login -p -h host -f user, because there are
* several different logins around, and it is hard to determined what kind of
* login the current system has. Also, we want to be able to execute commands
* on a tty.
*
* As far as I am concerned, the code I have written for this software
* can be used freely for any purpose. Any derived versions of this
* software must be clearly marked as such, and if the derived work is
* incompatible with the protocol description in the RFC file, it must be
* called by a name other than "ssh" or "Secure Shell".
*
* Copyright (c) 1999 Theo de Raadt. All rights reserved.
* Copyright (c) 1999 Markus Friedl. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "includes.h"
__RCSID("$NetBSD: sshlogin.c,v 1.13 2021/03/05 17:47:16 christos Exp $");
#include <sys/param.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <util.h>
#ifdef SUPPORT_UTMP
#include <utmp.h>
#endif
#ifdef SUPPORT_UTMPX
#include <utmpx.h>
#endif
#include <stdarg.h>
#include <limits.h>
#include "sshlogin.h"
#include "ssherr.h"
#include "log.h"
#include "sshbuf.h"
#include "misc.h"
#include "servconf.h"
#ifndef HOST_NAME_MAX
#define HOST_NAME_MAX MAXHOSTNAMELEN
#endif
extern struct sshbuf *loginmsg;
extern ServerOptions options;
/*
* Returns the time when the user last logged in. Returns 0 if the
* information is not available. This must be called before record_login.
* The host the user logged in from will be returned in buf.
*/
time_t
get_last_login_time(uid_t uid, const char *logname,
char *buf, size_t bufsize)
{
#ifdef SUPPORT_UTMPX
struct lastlogx llx, *llxp;
#endif
#ifdef SUPPORT_UTMP
struct lastlog ll;
int fd;
#endif
off_t pos, r;
buf[0] = '\0';
#ifdef SUPPORT_UTMPX
if ((llxp = getlastlogx(_PATH_LASTLOGX, uid, &llx)) != NULL) {
if (bufsize > sizeof(llxp->ll_host) + 1)
bufsize = sizeof(llxp->ll_host) + 1;
strncpy(buf, llxp->ll_host, bufsize - 1);
buf[bufsize - 1] = 0;
return llxp->ll_tv.tv_sec;
}
#endif
#ifdef SUPPORT_UTMP
fd = open(_PATH_LASTLOG, O_RDONLY);
if (fd == -1)
return 0;
pos = (off_t)uid * sizeof(ll);
r = lseek(fd, pos, SEEK_SET);
if (r == -1) {
error_f("lseek: %s", strerror(errno));
close(fd);
return (0);
}
if (r != pos) {
debug_f("truncated lastlog");
close(fd);
return (0);
}
if (read(fd, &ll, sizeof(ll)) != sizeof(ll)) {
close(fd);
return 0;
}
close(fd);
if (bufsize > sizeof(ll.ll_host) + 1)
bufsize = sizeof(ll.ll_host) + 1;
strncpy(buf, ll.ll_host, bufsize - 1);
buf[bufsize - 1] = '\0';
return (time_t)ll.ll_time;
#else
return 0;
#endif
}
/*
* Generate and store last login message. This must be done before
* login_login() is called and lastlog is updated.
*/
static void
store_lastlog_message(const char *user, uid_t uid)
{
char *time_string, hostname[HOST_NAME_MAX+1] = "";
time_t last_login_time;
int r;
if (!options.print_lastlog)
return;
last_login_time = get_last_login_time(uid, user, hostname,
sizeof(hostname));
if (last_login_time != 0) {
if ((time_string = ctime(&last_login_time)) != NULL)
time_string[strcspn(time_string, "\n")] = '\0';
if (strcmp(hostname, "") == 0)
r = sshbuf_putf(loginmsg, "Last login: %s\r\n",
time_string);
else
r = sshbuf_putf(loginmsg, "Last login: %s from %s\r\n",
time_string, hostname);
if (r != 0)
fatal_fr(r, "sshbuf_putf");
}
}
/*
* Records that the user has logged in. I wish these parts of operating
* systems were more standardized.
*/
void
record_login(pid_t pid, const char *tty, const char *user, uid_t uid,
const char *host, struct sockaddr *addr, socklen_t addrlen)
{
#if defined(SUPPORT_UTMP) || defined(SUPPORT_UTMPX)
int fd;
#endif
struct timeval tv;
#ifdef SUPPORT_UTMP
struct utmp u;
struct lastlog ll;
#endif
#ifdef SUPPORT_UTMPX
struct utmpx ux, *uxp = &ux;
struct lastlogx llx;
#endif
(void)gettimeofday(&tv, NULL);
/*
* XXX: why do we need to handle logout cases here?
* Isn't the function below taking care of this?
*/
/* save previous login details before writing new */
store_lastlog_message(user, uid);
#ifdef SUPPORT_UTMP
/* Construct an utmp/wtmp entry. */
memset(&u, 0, sizeof(u));
strncpy(u.ut_line, tty + 5, sizeof(u.ut_line));
u.ut_time = (time_t)tv.tv_sec;
strncpy(u.ut_name, user, sizeof(u.ut_name));
strncpy(u.ut_host, host, sizeof(u.ut_host));
login(&u);
/* Update lastlog unless actually recording a logout. */
if (*user != '\0') {
/*
* It is safer to memset the lastlog structure first because
* some systems might have some extra fields in it (e.g. SGI)
*/
memset(&ll, 0, sizeof(ll));
/* Update lastlog. */
ll.ll_time = time(NULL);
strncpy(ll.ll_line, tty + 5, sizeof(ll.ll_line));
strncpy(ll.ll_host, host, sizeof(ll.ll_host));
fd = open(_PATH_LASTLOG, O_RDWR);
if (fd >= 0) {
lseek(fd, (off_t)uid * sizeof(ll), SEEK_SET);
if (write(fd, &ll, sizeof(ll)) != sizeof(ll))
logit("Could not write %.100s: %.100s", _PATH_LASTLOG, strerror(errno));
close(fd);
}
}
#endif
#ifdef SUPPORT_UTMPX
/* Construct an utmpx/wtmpx entry. */
memset(&ux, 0, sizeof(ux));
strncpy(ux.ut_line, tty + 5, sizeof(ux.ut_line));
if (*user) {
ux.ut_pid = pid;
ux.ut_type = USER_PROCESS;
ux.ut_tv = tv;
strncpy(ux.ut_name, user, sizeof(ux.ut_name));
strncpy(ux.ut_host, host, sizeof(ux.ut_host));
/* XXX: need ut_id, use last 4 char of tty */
if (strlen(tty) > sizeof(ux.ut_id)) {
strncpy(ux.ut_id,
tty + strlen(tty) - sizeof(ux.ut_id),
sizeof(ux.ut_id));
} else
strncpy(ux.ut_id, tty, sizeof(ux.ut_id));
/* XXX: It would be better if we had sockaddr_storage here */
if (addrlen > sizeof(ux.ut_ss))
addrlen = sizeof(ux.ut_ss);
(void)memcpy(&ux.ut_ss, addr, addrlen);
if (pututxline(&ux) == NULL)
logit("could not add utmpx line: %.100s",
strerror(errno));
/* Update lastlog. */
(void)gettimeofday(&llx.ll_tv, NULL);
strncpy(llx.ll_line, tty + 5, sizeof(llx.ll_line));
strncpy(llx.ll_host, host, sizeof(llx.ll_host));
(void)memcpy(&llx.ll_ss, addr, addrlen);
if (updlastlogx(_PATH_LASTLOGX, uid, &llx) == -1)
logit("Could not update %.100s: %.100s",
_PATH_LASTLOGX, strerror(errno));
} else {
if ((uxp = getutxline(&ux)) == NULL)
logit("could not find utmpx line for %.100s", tty);
else {
uxp->ut_type = DEAD_PROCESS;
uxp->ut_tv = tv;
/* XXX: we don't record exit info yet */
if (pututxline(&ux) == NULL)
logit("could not replace utmpx line: %.100s",
strerror(errno));
}
}
endutxent();
updwtmpx(_PATH_WTMPX, uxp);
#endif
}
/* Records that the user has logged out. */
void
record_logout(pid_t pid, const char *tty)
{
#if defined(SUPPORT_UTMP) || defined(SUPPORT_UTMPX)
const char *line = tty + 5; /* /dev/ttyq8 -> ttyq8 */
#endif
#ifdef SUPPORT_UTMP
if (logout(line))
logwtmp(line, "", "");
#endif
#ifdef SUPPORT_UTMPX
/* XXX: no exit info yet */
if (logoutx(line, 0, DEAD_PROCESS))
logwtmpx(line, "", "", 0, DEAD_PROCESS);
#endif
}
|