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      1 /* $OpenBSD: sshlogin.c,v 1.31 2015/01/20 23:14:00 deraadt 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/socket.h>
     46 
     47 #include <netinet/in.h>
     48 
     49 #include <errno.h>
     50 #include <fcntl.h>
     51 #include <stdarg.h>
     52 #include <stdio.h>
     53 #include <string.h>
     54 #include <time.h>
     55 #include <unistd.h>
     56 #include <limits.h>
     57 
     58 #include "loginrec.h"
     59 #include "log.h"
     60 #include "buffer.h"
     61 #include "misc.h"
     62 #include "servconf.h"
     63 
     64 extern Buffer loginmsg;
     65 extern ServerOptions options;
     66 
     67 /*
     68  * Returns the time when the user last logged in.  Returns 0 if the
     69  * information is not available.  This must be called before record_login.
     70  * The host the user logged in from will be returned in buf.
     71  */
     72 time_t
     73 get_last_login_time(uid_t uid, const char *logname,
     74     char *buf, size_t bufsize)
     75 {
     76 	struct logininfo li;
     77 
     78 	login_get_lastlog(&li, uid);
     79 	strlcpy(buf, li.hostname, bufsize);
     80 	return (time_t)li.tv_sec;
     81 }
     82 
     83 /*
     84  * Generate and store last login message.  This must be done before
     85  * login_login() is called and lastlog is updated.
     86  */
     87 static void
     88 store_lastlog_message(const char *user, uid_t uid)
     89 {
     90 #ifndef NO_SSH_LASTLOG
     91 	char *time_string, hostname[HOST_NAME_MAX+1] = "", buf[512];
     92 	time_t last_login_time;
     93 
     94 	if (!options.print_lastlog)
     95 		return;
     96 
     97 # ifdef CUSTOM_SYS_AUTH_GET_LASTLOGIN_MSG
     98 	time_string = sys_auth_get_lastlogin_msg(user, uid);
     99 	if (time_string != NULL) {
    100 		buffer_append(&loginmsg, time_string, strlen(time_string));
    101 		free(time_string);
    102 	}
    103 # else
    104 	last_login_time = get_last_login_time(uid, user, hostname,
    105 	    sizeof(hostname));
    106 
    107 	if (last_login_time != 0) {
    108 		time_string = ctime(&last_login_time);
    109 		time_string[strcspn(time_string, "\n")] = '\0';
    110 		if (strcmp(hostname, "") == 0)
    111 			snprintf(buf, sizeof(buf), "Last login: %s\r\n",
    112 			    time_string);
    113 		else
    114 			snprintf(buf, sizeof(buf), "Last login: %s from %s\r\n",
    115 			    time_string, hostname);
    116 		buffer_append(&loginmsg, buf, strlen(buf));
    117 	}
    118 # endif /* CUSTOM_SYS_AUTH_GET_LASTLOGIN_MSG */
    119 #endif /* NO_SSH_LASTLOG */
    120 }
    121 
    122 /*
    123  * Records that the user has logged in.  I wish these parts of operating
    124  * systems were more standardized.
    125  */
    126 void
    127 record_login(pid_t pid, const char *tty, const char *user, uid_t uid,
    128     const char *host, struct sockaddr *addr, socklen_t addrlen)
    129 {
    130 	struct logininfo *li;
    131 
    132 	/* save previous login details before writing new */
    133 	store_lastlog_message(user, uid);
    134 
    135 	li = login_alloc_entry(pid, user, host, tty);
    136 	login_set_addr(li, addr, addrlen);
    137 	login_login(li);
    138 	login_free_entry(li);
    139 }
    140 
    141 #ifdef LOGIN_NEEDS_UTMPX
    142 void
    143 record_utmp_only(pid_t pid, const char *ttyname, const char *user,
    144 		 const char *host, struct sockaddr *addr, socklen_t addrlen)
    145 {
    146 	struct logininfo *li;
    147 
    148 	li = login_alloc_entry(pid, user, host, ttyname);
    149 	login_set_addr(li, addr, addrlen);
    150 	login_utmp_only(li);
    151 	login_free_entry(li);
    152 }
    153 #endif
    154 
    155 /* Records that the user has logged out. */
    156 void
    157 record_logout(pid_t pid, const char *tty, const char *user)
    158 {
    159 	struct logininfo *li;
    160 
    161 	li = login_alloc_entry(pid, user, NULL, tty);
    162 	login_logout(li);
    163 	login_free_entry(li);
    164 }
    165