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/* $OpenBSD: failedlogin.c,v 1.11 2002/02/16 21:27:48 millert Exp $ */
/*
* Copyright (c) 1996 Todd C. Miller <Todd.Miller@courtesan.com>
* 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.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED ``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.
*/
#ifndef lint
static char rcsid[] = "$OpenBSD: failedlogin.c,v 1.11 2002/02/16 21:27:48 millert Exp $";
#endif /* not lint */
/*
* failedlogin.c
* Log to failedlogin file and read from it, reporting the number of
* failed logins since the last good login and when/from where
* the last failed login was.
*/
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <utmp.h>
#include "pathnames.h"
struct badlogin {
char bl_line[UT_LINESIZE]; /* tty used */
char bl_name[UT_NAMESIZE]; /* remote username */
char bl_host[UT_HOSTSIZE]; /* remote host */
time_t bl_time; /* time of the login attempt */
size_t count; /* number of bad logins */
};
void log_failedlogin(uid_t, char *, char *, char *);
int check_failedlogin(uid_t);
/*
* Log a bad login to the failedlogin file.
*/
void
log_failedlogin(uid, host, name, tty)
uid_t uid;
char *host, *name, *tty;
{
struct badlogin failedlogin;
int fd;
/* Add O_CREAT if you want to create failedlogin if it doesn't exist */
if ((fd = open(_PATH_FAILEDLOGIN, O_RDWR, S_IREAD|S_IWRITE)) >= 0) {
(void)lseek(fd, (off_t)uid * sizeof(failedlogin), SEEK_SET);
/* Read in last bad login so can get the count */
if (read(fd, (char *)&failedlogin, sizeof(failedlogin)) !=
sizeof(failedlogin) || failedlogin.bl_time == 0)
memset((void *)&failedlogin, 0, sizeof(failedlogin));
(void)lseek(fd, (off_t)uid * sizeof(failedlogin), SEEK_SET);
/* Increment count of bad logins */
++failedlogin.count;
(void)time(&failedlogin.bl_time);
strncpy(failedlogin.bl_line, tty, sizeof(failedlogin.bl_line));
if (host)
strncpy(failedlogin.bl_host, host, sizeof(failedlogin.bl_host));
else
*failedlogin.bl_host = '\0'; /* NULL host field */
if (name)
strncpy(failedlogin.bl_name, name, sizeof(failedlogin.bl_name));
else
*failedlogin.bl_name = '\0'; /* NULL name field */
(void)write(fd, (char *)&failedlogin, sizeof(failedlogin));
(void)close(fd);
}
}
/*
* Check the failedlogin file and report about the number of unsuccessful
* logins and info about the last one in lastlogin style.
* NOTE: zeros the count field since this is assumed to be called after the
* user has been validated.
*/
int
check_failedlogin(uid)
uid_t uid;
{
int fd;
struct badlogin failedlogin;
int was_bad = 0;
(void)memset((void *)&failedlogin, 0, sizeof(failedlogin));
if ((fd = open(_PATH_FAILEDLOGIN, O_RDWR, 0)) >= 0) {
(void)lseek(fd, (off_t)uid * sizeof(failedlogin), SEEK_SET);
if (read(fd, (char *)&failedlogin, sizeof(failedlogin)) ==
sizeof(failedlogin) && failedlogin.count > 0 ) {
/* There was a bad login */
was_bad = 1;
if (failedlogin.count > 1)
(void)printf("There have been %lu unsuccessful "
"login attempts to your account.\n",
(u_long)failedlogin.count);
(void)printf("Last unsuccessful login: %.*s", 24-5,
(char *)ctime(&failedlogin.bl_time));
(void)printf(" on %.*s",
(int)sizeof(failedlogin.bl_line),
failedlogin.bl_line);
if (*failedlogin.bl_host != '\0') {
if (*failedlogin.bl_name != '\0')
(void)printf(" from %.*s@%.*s",
(int)sizeof(failedlogin.bl_name),
failedlogin.bl_name,
(int)sizeof(failedlogin.bl_host),
failedlogin.bl_host);
else
(void)printf(" from %.*s",
(int)sizeof(failedlogin.bl_host),
failedlogin.bl_host);
}
(void)putchar('\n');
/* Reset since this is a good login and write record */
failedlogin.count = 0;
(void)lseek(fd, (off_t)uid * sizeof(failedlogin),
SEEK_SET);
(void)write(fd, (char *)&failedlogin,
sizeof(failedlogin));
}
(void)close(fd);
}
return(was_bad);
}
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