Annotation of src/usr.bin/ssh/sshlogin.c, Revision 1.31
1.31 ! deraadt 1: /* $OpenBSD: sshlogin.c,v 1.30 2015/01/16 06:40:12 deraadt Exp $ */
1.1 djm 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:
1.20 stevesk 42: #include <sys/types.h>
1.25 deraadt 43: #include <sys/socket.h>
1.20 stevesk 44:
1.19 stevesk 45: #include <errno.h>
1.18 stevesk 46: #include <fcntl.h>
1.24 stevesk 47: #include <stdio.h>
1.22 stevesk 48: #include <string.h>
1.21 stevesk 49: #include <time.h>
1.20 stevesk 50: #include <unistd.h>
1.1 djm 51: #include <util.h>
52: #include <utmp.h>
1.25 deraadt 53: #include <stdarg.h>
1.31 ! deraadt 54: #include <limits.h>
1.18 stevesk 55:
1.1 djm 56: #include "sshlogin.h"
57: #include "log.h"
1.10 dtucker 58: #include "buffer.h"
1.29 millert 59: #include "misc.h"
1.10 dtucker 60: #include "servconf.h"
61:
62: extern Buffer loginmsg;
63: extern ServerOptions options;
1.1 djm 64:
65: /*
66: * Returns the time when the user last logged in. Returns 0 if the
67: * information is not available. This must be called before record_login.
68: * The host the user logged in from will be returned in buf.
69: */
1.17 deraadt 70: time_t
1.1 djm 71: get_last_login_time(uid_t uid, const char *logname,
1.17 deraadt 72: char *buf, size_t bufsize)
1.1 djm 73: {
74: struct lastlog ll;
75: char *lastlog;
76: int fd;
1.11 djm 77: off_t pos, r;
1.1 djm 78:
79: lastlog = _PATH_LASTLOG;
80: buf[0] = '\0';
81:
82: fd = open(lastlog, O_RDONLY);
83: if (fd < 0)
84: return 0;
1.11 djm 85:
86: pos = (long) uid * sizeof(ll);
87: r = lseek(fd, pos, SEEK_SET);
88: if (r == -1) {
1.13 djm 89: error("%s: lseek: %s", __func__, strerror(errno));
1.27 djm 90: close(fd);
1.11 djm 91: return (0);
92: }
93: if (r != pos) {
94: debug("%s: truncated lastlog", __func__);
1.27 djm 95: close(fd);
1.11 djm 96: return (0);
97: }
1.1 djm 98: if (read(fd, &ll, sizeof(ll)) != sizeof(ll)) {
99: close(fd);
100: return 0;
101: }
102: close(fd);
103: if (bufsize > sizeof(ll.ll_host) + 1)
104: bufsize = sizeof(ll.ll_host) + 1;
105: strncpy(buf, ll.ll_host, bufsize - 1);
1.9 dtucker 106: buf[bufsize - 1] = '\0';
1.17 deraadt 107: return (time_t)ll.ll_time;
1.1 djm 108: }
109:
110: /*
1.10 dtucker 111: * Generate and store last login message. This must be done before
112: * login_login() is called and lastlog is updated.
113: */
1.12 djm 114: static void
1.10 dtucker 115: store_lastlog_message(const char *user, uid_t uid)
116: {
1.31 ! deraadt 117: char *time_string, hostname[HOST_NAME_MAX+1] = "", buf[512];
1.10 dtucker 118: time_t last_login_time;
119:
120: if (!options.print_lastlog)
121: return;
122:
123: last_login_time = get_last_login_time(uid, user, hostname,
124: sizeof(hostname));
125:
126: if (last_login_time != 0) {
127: time_string = ctime(&last_login_time);
1.26 gilles 128: time_string[strcspn(time_string, "\n")] = '\0';
1.10 dtucker 129: if (strcmp(hostname, "") == 0)
130: snprintf(buf, sizeof(buf), "Last login: %s\r\n",
131: time_string);
132: else
133: snprintf(buf, sizeof(buf), "Last login: %s from %s\r\n",
134: time_string, hostname);
135: buffer_append(&loginmsg, buf, strlen(buf));
136: }
137: }
138:
139: /*
1.7 markus 140: * Records that the user has logged in. I wish these parts of operating
141: * systems were more standardized.
1.1 djm 142: */
143: void
1.8 avsm 144: record_login(pid_t pid, const char *tty, const char *user, uid_t uid,
1.15 deraadt 145: const char *host, struct sockaddr *addr, socklen_t addrlen)
1.1 djm 146: {
147: int fd;
148: struct lastlog ll;
149: char *lastlog;
150: struct utmp u;
1.10 dtucker 151:
152: /* save previous login details before writing new */
153: store_lastlog_message(user, uid);
1.1 djm 154:
155: /* Construct an utmp/wtmp entry. */
156: memset(&u, 0, sizeof(u));
1.8 avsm 157: strncpy(u.ut_line, tty + 5, sizeof(u.ut_line));
1.1 djm 158: u.ut_time = time(NULL);
159: strncpy(u.ut_name, user, sizeof(u.ut_name));
160: strncpy(u.ut_host, host, sizeof(u.ut_host));
161:
162: login(&u);
163: lastlog = _PATH_LASTLOG;
164:
165: /* Update lastlog unless actually recording a logout. */
166: if (strcmp(user, "") != 0) {
167: /*
1.28 tedu 168: * It is safer to memset the lastlog structure first because
1.1 djm 169: * some systems might have some extra fields in it (e.g. SGI)
170: */
171: memset(&ll, 0, sizeof(ll));
172:
173: /* Update lastlog. */
174: ll.ll_time = time(NULL);
1.8 avsm 175: strncpy(ll.ll_line, tty + 5, sizeof(ll.ll_line));
1.1 djm 176: strncpy(ll.ll_host, host, sizeof(ll.ll_host));
177: fd = open(lastlog, O_RDWR);
178: if (fd >= 0) {
179: lseek(fd, (off_t) ((long) uid * sizeof(ll)), SEEK_SET);
180: if (write(fd, &ll, sizeof(ll)) != sizeof(ll))
1.6 itojun 181: logit("Could not write %.100s: %.100s", lastlog, strerror(errno));
1.1 djm 182: close(fd);
183: }
184: }
185: }
186:
187: /* Records that the user has logged out. */
188: void
1.8 avsm 189: record_logout(pid_t pid, const char *tty)
1.1 djm 190: {
1.8 avsm 191: const char *line = tty + 5; /* /dev/ttyq8 -> ttyq8 */
1.1 djm 192: if (logout(line))
193: logwtmp(line, "", "");
194: }