sshlogin.c

   1 /* $OpenBSD: sshlogin.c,v 1.27 2011/01/11 06:06:09 djm 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/param.h>
  46 #include <sys/socket.h>
  47
  48 #include <netinet/in.h>
  49
  50 #include <errno.h>
  51 #include <fcntl.h>
  52 #include <stdarg.h>
  53 #include <stdio.h>
  54 #include <string.h>
  55 #include <time.h>
  56 #include <unistd.h>
  57
  58 #include "loginrec.h"
  59 #include "log.h"
  60 #include "buffer.h"
  61 #include "servconf.h"
  62
  63 extern Buffer loginmsg;
  64 extern ServerOptions options;
  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  */
  71 time_t
  72 get_last_login_time(uid_t uid, const char *logname,
  73     char *buf, size_t bufsize)
  74 {
  75         struct logininfo li;
  76
  77         login_get_lastlog(&li, uid);
  78         strlcpy(buf, li.hostname, bufsize);
  79         return (time_t)li.tv_sec;
  80 }
  81
  82 /*
  83  * Generate and store last login message.  This must be done before
  84  * login_login() is called and lastlog is updated.
  85  */
  86 static void
  87 store_lastlog_message(const char *user, uid_t uid)
  88 {
  89 #ifndef NO_SSH_LASTLOG
  90         char *time_string, hostname[MAXHOSTNAMELEN] = "", buf[512];
  91         time_t last_login_time;
  92
  93         if (!options.print_lastlog)
  94                 return;
  95
  96 # ifdef CUSTOM_SYS_AUTH_GET_LASTLOGIN_MSG
  97         time_string = sys_auth_get_lastlogin_msg(user, uid);
  98         if (time_string != NULL) {
  99                 buffer_append(&loginmsg, time_string, strlen(time_string));
 100                 xfree(time_string);
 101         }
 102 # else
 103         last_login_time = get_last_login_time(uid, user, hostname,
 104             sizeof(hostname));
 105
 106         if (last_login_time != 0) {
 107                 time_string = ctime(&last_login_time);
 108                 time_string[strcspn(time_string, "\n")] = '\0';
 109                 if (strcmp(hostname, "") == 0)
 110                         snprintf(buf, sizeof(buf), "Last login: %s\r\n",
 111                             time_string);
 112                 else
 113                         snprintf(buf, sizeof(buf), "Last login: %s from %s\r\n",
 114                             time_string, hostname);
 115                 buffer_append(&loginmsg, buf, strlen(buf));
 116         }
 117 # endif /* CUSTOM_SYS_AUTH_GET_LASTLOGIN_MSG */
 118 #endif /* NO_SSH_LASTLOG */
 119 }
 120
 121 /*
 122  * Records that the user has logged in.  I wish these parts of operating
 123  * systems were more standardized.
 124  */
 125 void
 126 record_login(pid_t pid, const char *tty, const char *user, uid_t uid,
 127     const char *host, struct sockaddr *addr, socklen_t addrlen)
 128 {
 129         struct logininfo *li;
 130
 131         /* save previous login details before writing new */
 132         store_lastlog_message(user, uid);
 133
 134         li = login_alloc_entry(pid, user, host, tty);
 135         login_set_addr(li, addr, addrlen);
 136         login_login(li);
 137         login_free_entry(li);
 138 }
 139
 140 #ifdef LOGIN_NEEDS_UTMPX
 141 void
 142 record_utmp_only(pid_t pid, const char *ttyname, const char *user,
 143                  const char *host, struct sockaddr *addr, socklen_t addrlen)
 144 {
 145         struct logininfo *li;
 146
 147         li = login_alloc_entry(pid, user, host, ttyname);
 148         login_set_addr(li, addr, addrlen);
 149         login_utmp_only(li);
 150         login_free_entry(li);
 151 }
 152 #endif
 153
 154 /* Records that the user has logged out. */
 155 void
 156 record_logout(pid_t pid, const char *tty, const char *user)
 157 {
 158         struct logininfo *li;
 159
 160         li = login_alloc_entry(pid, user, NULL, tty);
 161         login_logout(li);
 162         login_free_entry(li);
 163 }