Annotation of src/usr.bin/ssh/sshlogin.c, Revision 1.33
1.33 ! markus 1: /* $OpenBSD: sshlogin.c,v 1.32 2015/12/26 20:51:35 guenther 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"
1.33 ! markus 57: #include "ssherr.h"
1.1 djm 58: #include "log.h"
1.33 ! markus 59: #include "sshbuf.h"
1.29 millert 60: #include "misc.h"
1.10 dtucker 61: #include "servconf.h"
62:
1.33 ! markus 63: extern struct sshbuf *loginmsg;
1.10 dtucker 64: extern ServerOptions options;
1.1 djm 65:
66: /*
67: * Returns the time when the user last logged in. Returns 0 if the
68: * information is not available. This must be called before record_login.
69: * The host the user logged in from will be returned in buf.
70: */
1.17 deraadt 71: time_t
1.1 djm 72: get_last_login_time(uid_t uid, const char *logname,
1.17 deraadt 73: char *buf, size_t bufsize)
1.1 djm 74: {
75: struct lastlog ll;
76: char *lastlog;
77: int fd;
1.11 djm 78: off_t pos, r;
1.1 djm 79:
80: lastlog = _PATH_LASTLOG;
81: buf[0] = '\0';
82:
83: fd = open(lastlog, O_RDONLY);
84: if (fd < 0)
85: return 0;
1.11 djm 86:
1.32 guenther 87: pos = (off_t)uid * sizeof(ll);
1.11 djm 88: r = lseek(fd, pos, SEEK_SET);
89: if (r == -1) {
1.13 djm 90: error("%s: lseek: %s", __func__, strerror(errno));
1.27 djm 91: close(fd);
1.11 djm 92: return (0);
93: }
94: if (r != pos) {
95: debug("%s: truncated lastlog", __func__);
1.27 djm 96: close(fd);
1.11 djm 97: return (0);
98: }
1.1 djm 99: if (read(fd, &ll, sizeof(ll)) != sizeof(ll)) {
100: close(fd);
101: return 0;
102: }
103: close(fd);
104: if (bufsize > sizeof(ll.ll_host) + 1)
105: bufsize = sizeof(ll.ll_host) + 1;
106: strncpy(buf, ll.ll_host, bufsize - 1);
1.9 dtucker 107: buf[bufsize - 1] = '\0';
1.17 deraadt 108: return (time_t)ll.ll_time;
1.1 djm 109: }
110:
111: /*
1.10 dtucker 112: * Generate and store last login message. This must be done before
113: * login_login() is called and lastlog is updated.
114: */
1.12 djm 115: static void
1.10 dtucker 116: store_lastlog_message(const char *user, uid_t uid)
117: {
1.33 ! markus 118: char *time_string, hostname[HOST_NAME_MAX+1] = "";
1.10 dtucker 119: time_t last_login_time;
1.33 ! markus 120: int r;
1.10 dtucker 121:
122: if (!options.print_lastlog)
123: return;
124:
125: last_login_time = get_last_login_time(uid, user, hostname,
126: sizeof(hostname));
127:
128: if (last_login_time != 0) {
129: time_string = ctime(&last_login_time);
1.26 gilles 130: time_string[strcspn(time_string, "\n")] = '\0';
1.10 dtucker 131: if (strcmp(hostname, "") == 0)
1.33 ! markus 132: r = sshbuf_putf(loginmsg, "Last login: %s\r\n",
1.10 dtucker 133: time_string);
134: else
1.33 ! markus 135: r = sshbuf_putf(loginmsg, "Last login: %s from %s\r\n",
1.10 dtucker 136: time_string, hostname);
1.33 ! markus 137: if (r != 0)
! 138: fatal("%s: buffer error: %s", __func__, ssh_err(r));
1.10 dtucker 139: }
140: }
141:
142: /*
1.7 markus 143: * Records that the user has logged in. I wish these parts of operating
144: * systems were more standardized.
1.1 djm 145: */
146: void
1.8 avsm 147: record_login(pid_t pid, const char *tty, const char *user, uid_t uid,
1.15 deraadt 148: const char *host, struct sockaddr *addr, socklen_t addrlen)
1.1 djm 149: {
150: int fd;
151: struct lastlog ll;
152: char *lastlog;
153: struct utmp u;
1.10 dtucker 154:
155: /* save previous login details before writing new */
156: store_lastlog_message(user, uid);
1.1 djm 157:
158: /* Construct an utmp/wtmp entry. */
159: memset(&u, 0, sizeof(u));
1.8 avsm 160: strncpy(u.ut_line, tty + 5, sizeof(u.ut_line));
1.1 djm 161: u.ut_time = time(NULL);
162: strncpy(u.ut_name, user, sizeof(u.ut_name));
163: strncpy(u.ut_host, host, sizeof(u.ut_host));
164:
165: login(&u);
166: lastlog = _PATH_LASTLOG;
167:
168: /* Update lastlog unless actually recording a logout. */
169: if (strcmp(user, "") != 0) {
170: /*
1.28 tedu 171: * It is safer to memset the lastlog structure first because
1.1 djm 172: * some systems might have some extra fields in it (e.g. SGI)
173: */
174: memset(&ll, 0, sizeof(ll));
175:
176: /* Update lastlog. */
177: ll.ll_time = time(NULL);
1.8 avsm 178: strncpy(ll.ll_line, tty + 5, sizeof(ll.ll_line));
1.1 djm 179: strncpy(ll.ll_host, host, sizeof(ll.ll_host));
180: fd = open(lastlog, O_RDWR);
181: if (fd >= 0) {
1.32 guenther 182: lseek(fd, (off_t)uid * sizeof(ll), SEEK_SET);
1.1 djm 183: if (write(fd, &ll, sizeof(ll)) != sizeof(ll))
1.6 itojun 184: logit("Could not write %.100s: %.100s", lastlog, strerror(errno));
1.1 djm 185: close(fd);
186: }
187: }
188: }
189:
190: /* Records that the user has logged out. */
191: void
1.8 avsm 192: record_logout(pid_t pid, const char *tty)
1.1 djm 193: {
1.8 avsm 194: const char *line = tty + 5; /* /dev/ttyq8 -> ttyq8 */
1.1 djm 195: if (logout(line))
196: logwtmp(line, "", "");
197: }
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