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      1 /* $OpenBSD: sshlogin.c,v 1.27 2011/01/11 06:06:09 djm Exp $ */
      2 /*
      3  * Author: Tatu Ylonen <ylo (at) cs.hut.fi>
      4  * Copyright (c) 1995 Tatu Ylonen <ylo (at) 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 }
    164