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deb-mbse/mbsebbs/failure.c
2002-01-02 22:17:58 +00:00

274 lines
6.5 KiB
C

/*****************************************************************************
*
* $Id$
* Purpose ...............: MBSE BBS Shadow Password Suite
* Original Source .......: Shadow Password Suite
* Original Copyrioght ...: Julianne Frances Haugh and others.
*
*****************************************************************************
* Copyright (C) 1997-2001
*
* Michiel Broek FIDO: 2:280/2802
* Beekmansbos 10
* 1971 BV IJmuiden
* the Netherlands
*
* This file is part of MBSE BBS.
*
* This BBS is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2, or (at your option) any
* later version.
*
* MBSE BBS is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with MBSE BBS; see the file COPYING. If not, write to the Free
* Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
*****************************************************************************/
#include "../config.h"
#include <fcntl.h>
#include <stdio.h>
#include "mblogin.h"
#include "getdef.h"
#include <utmp.h>
#include "failure.h"
#define YEAR (365L*DAY)
/*
* failure - make failure entry
*
* failure() creates a new (struct faillog) entry or updates an
* existing one with the current failed login information.
*/
void failure(uid_t uid, const char *tty, struct faillog *fl)
{
int fd;
/*
* Don't do anything if failure logging isn't set up.
*/
if ((fd = open(FAILLOG_FILE, O_RDWR)) < 0)
return;
/*
* The file is indexed by uid value meaning that shared UID's
* share failure log records. That's OK since they really
* share just about everything else ...
*/
lseek(fd, (off_t) (sizeof *fl) * uid, SEEK_SET);
if (read(fd, (char *) fl, sizeof *fl) != sizeof *fl)
memzero(fl, sizeof *fl);
/*
* Update the record. We increment the failure count to log the
* latest failure. The only concern here is overflow, and we'll
* check for that. The line name and time of day are both
* updated as well.
*/
if (fl->fail_cnt + 1 > 0)
fl->fail_cnt++;
strncpy(fl->fail_line, tty, sizeof fl->fail_line);
time(&fl->fail_time);
/*
* Seek back to the correct position in the file and write the
* record out. Ideally we should lock the file in case the same
* account is being logged simultaneously. But the risk doesn't
* seem that great.
*/
lseek(fd, (off_t) (sizeof *fl) * uid, SEEK_SET);
write(fd, (char *) fl, sizeof *fl);
close(fd);
}
static int too_many_failures(const struct faillog *fl)
{
time_t now;
if (fl->fail_max == 0 || fl->fail_cnt < fl->fail_max)
return 0;
if (fl->fail_locktime == 0)
return 1; /* locked until reset manually */
time(&now);
if (fl->fail_time + fl->fail_locktime > now)
return 0; /* enough time since last failure */
return 1;
}
/*
* failcheck - check for failures > allowable
*
* failcheck() is called AFTER the password has been validated. If the
* account has been "attacked" with too many login failures, failcheck()
* returns FALSE to indicate that the login should be denied even though
* the password is valid.
*/
int failcheck(uid_t uid, struct faillog *fl, int failed)
{
int fd;
struct faillog fail;
/*
* Suppress the check if the log file isn't there.
*/
if ((fd = open(FAILLOG_FILE, O_RDWR)) < 0)
return 1;
/*
* Get the record from the file and determine if the user has
* exceeded the failure limit. If "max" is zero, any number
* of failures are permitted. Only when "max" is non-zero and
* "cnt" is greater than or equal to "max" is the account
* considered to be locked.
*
* If read fails, there is no record for this user yet (the
* file is initially zero length and extended by writes), so
* no need to reset the count.
*/
lseek (fd, (off_t) (sizeof *fl) * uid, SEEK_SET);
if (read(fd, (char *) fl, sizeof *fl) != sizeof *fl) {
close(fd);
return 1;
}
if (too_many_failures(fl)) {
close(fd);
return 0;
}
/*
* The record is updated if this is not a failure. The count will
* be reset to zero, but the rest of the information will be left
* in the record in case someone wants to see where the failed
* login originated.
*/
if (!failed) {
fail = *fl;
fail.fail_cnt = 0;
lseek (fd, (off_t) sizeof fail * uid, SEEK_SET);
write (fd, (char *) &fail, sizeof fail);
}
close (fd);
return 1;
}
/*
* failprint - print line of failure information
*
* failprint takes a (struct faillog) entry and formats it into a
* message which is displayed at login time.
*/
void failprint(const struct faillog *fail)
{
struct tm *tp;
#if HAVE_STRFTIME
char lasttimeb[256];
char *lasttime = lasttimeb;
const char *fmt;
#else
char *lasttime;
#endif
time_t NOW;
if (fail->fail_cnt == 0)
return;
tp = localtime (&(fail->fail_time));
time(&NOW);
#if HAVE_STRFTIME
/*
* Only print as much date and time info as it needed to
* know when the failure was.
*/
if (NOW - fail->fail_time >= YEAR)
fmt = "%Y";
else if (NOW - fail->fail_time >= DAY)
fmt = "%A %T";
else
fmt = "%T";
strftime(lasttimeb, sizeof lasttimeb, fmt, tp);
#else
/*
* Do the same thing, but don't use strftime since it
* probably doesn't exist on this system
*/
lasttime = asctime (tp);
lasttime[24] = '\0';
if (NOW - fail->fail_time < YEAR)
lasttime[19] = '\0';
if (NOW - fail->fail_time < DAY)
lasttime = lasttime + 11;
if (*lasttime == ' ')
lasttime++;
#endif
printf ("%d %s since last login. Last was %s on %s.\n",
fail->fail_cnt, fail->fail_cnt > 1 ? "failures":"failure",
lasttime, fail->fail_line);
}
/*
* failtmp - update the cummulative failure log
*
* failtmp updates the (struct utmp) formatted failure log which
* maintains a record of all login failures.
*/
void failtmp(const struct utmp *failent)
{
char *ftmp;
int fd;
/*
* Get the name of the failure file. If no file has been defined
* in login.defs, don't do this.
*/
if (!(ftmp = getdef_str("FTMP_FILE")))
return;
/*
* Open the file for append. It must already exist for this
* feature to be used.
*/
if ((fd = open(ftmp, O_WRONLY|O_APPEND)) == -1)
return;
/*
* Output the new failure record and close the log file.
*/
write(fd, (const char *) failent, sizeof *failent);
close(fd);
}