/* $OpenBSD: sshlogin.c,v 1.37 2026/02/16 23:47:06 jsg Exp $ */

/*

 * Author: Tatu Ylonen <ylo@cs.hut.fi>

 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland

 *                    All rights reserved

 * This file performs some of the things login(1) normally does.  We cannot

 * easily use something like login -p -h host -f user, because there are

 * several different logins around, and it is hard to determined what kind of

 * login the current system has.  Also, we want to be able to execute commands

 * on a tty.

 *

 * As far as I am concerned, the code I have written for this software

 * can be used freely for any purpose.  Any derived versions of this

 * software must be clearly marked as such, and if the derived work is

 * incompatible with the protocol description in the RFC file, it must be

 * called by a name other than "ssh" or "Secure Shell".

 *

 * Copyright (c) 1999 Theo de Raadt.  All rights reserved.

 * Copyright (c) 1999 Markus Friedl.  All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#include "includes.h"

#include <sys/types.h>

#include <sys/socket.h>

#include <netinet/in.h>

#include <errno.h>

#include <fcntl.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <time.h>

#include <unistd.h>

#include <limits.h>

#include "sshlogin.h"

#include "ssherr.h"

#include "loginrec.h"

#include "log.h"

#include "sshbuf.h"

#include "misc.h"

#include "servconf.h"

extern struct sshbuf *loginmsg;

extern ServerOptions options;

/*

 * Returns the time when the user last logged in.  Returns 0 if the

 * information is not available.  This must be called before record_login.

 * The host the user logged in from will be returned in buf.

 */

time_t

get_last_login_time(uid_t uid, const char *logname,

    char *buf, size_t bufsize)

{

  struct logininfo li;

  login_get_lastlog(&li, uid);

  strlcpy(buf, li.hostname, bufsize);

  return (time_t)li.tv_sec;

}

/*

 * Generate and store last login message.  This must be done before

 * login_login() is called and lastlog is updated.

 */

static void

store_lastlog_message(const char *user, uid_t uid)

{

#ifndef NO_SSH_LASTLOG

# ifndef CUSTOM_SYS_AUTH_GET_LASTLOGIN_MSG

  char hostname[HOST_NAME_MAX+1] = "";

  time_t last_login_time;

# endif

  char *time_string;

  int r;

  if (!options.print_lastlog)

    return;

# ifdef CUSTOM_SYS_AUTH_GET_LASTLOGIN_MSG

  time_string = sys_auth_get_lastlogin_msg(user, uid);

  if (time_string != NULL) {

    if ((r = sshbuf_put(loginmsg,

        time_string, strlen(time_string))) != 0)

      fatal_fr(r, "buffer error");

    free(time_string);

  }

# else

  last_login_time = get_last_login_time(uid, user, hostname,

      sizeof(hostname));

  if (last_login_time != 0) {

    time_string = ctime(&last_login_time);

    time_string[strcspn(time_string, "\n")] = '\0';

    if (strcmp(hostname, "") == 0)

      r = sshbuf_putf(loginmsg, "Last login: %s\r\n",

          time_string);

    else

      r = sshbuf_putf(loginmsg, "Last login: %s from %s\r\n",

          time_string, hostname);

    if (r != 0)

      fatal_fr(r, "sshbuf_putf");

  }

# endif /* CUSTOM_SYS_AUTH_GET_LASTLOGIN_MSG */

#endif /* NO_SSH_LASTLOG */

}

/*

 * Records that the user has logged in.  I wish these parts of operating

 * systems were more standardized.

 */

void

record_login(pid_t pid, const char *tty, const char *user, uid_t uid,

    const char *host, struct sockaddr *addr, socklen_t addrlen)

{

  struct logininfo *li;

  /* save previous login details before writing new */

  store_lastlog_message(user, uid);

  li = login_alloc_entry(pid, user, host, tty);

  login_set_addr(li, addr, addrlen);

  login_login(li);

  login_free_entry(li);

}

#ifdef LOGIN_NEEDS_UTMPX

void

record_utmp_only(pid_t pid, const char *ttyname, const char *user,

     const char *host, struct sockaddr *addr, socklen_t addrlen)

{

  struct logininfo *li;

  li = login_alloc_entry(pid, user, host, ttyname);

  login_set_addr(li, addr, addrlen);

  login_utmp_only(li);

  login_free_entry(li);

}

#endif

/* Records that the user has logged out. */

void

record_logout(pid_t pid, const char *tty, const char *user)

{

  struct logininfo *li;

  li = login_alloc_entry(pid, user, NULL, tty);

  login_logout(li);

  login_free_entry(li);

}