shadow/libmisc/obscure.c

280 lines
6.4 KiB
C

/*
* Copyright 1989 - 1994, Julianne Frances Haugh
* 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. Neither the name of Julianne F. Haugh nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JULIE HAUGH AND CONTRIBUTORS ``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 JULIE HAUGH OR CONTRIBUTORS 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 <config.h>
#ifndef USE_PAM
#include "rcsid.h"
RCSID ("$Id: obscure.c,v 1.12 2005/03/24 04:29:23 kloczek Exp $")
/*
* This version of obscure.c contains modifications to support "cracklib"
* by Alec Muffet (alec.muffett@uk.sun.com). You must obtain the Cracklib
* library source code for this function to operate.
*/
#include <ctype.h>
#include <stdio.h>
#include "prototypes.h"
#include "defines.h"
#include "getdef.h"
/*
* can't be a palindrome - like `R A D A R' or `M A D A M'
*/
/*ARGSUSED*/ static int palindrome (const char *old, const char *new)
{
int i, j;
i = strlen (new);
for (j = 0; j < i; j++)
if (new[i - j - 1] != new[j])
return 0;
return 1;
}
/*
* more than half of the characters are different ones.
*/
/*ARGSUSED*/ static int similar (const char *old, const char *new)
{
int i, j;
/*
* XXX - sometimes this fails when changing from a simple password
* to a really long one (MD5). For now, I just return success if
* the new password is long enough. Please feel free to suggest
* something better... --marekm
*/
if (strlen (new) >= 8)
return 0;
for (i = j = 0; new[i] && old[i]; i++)
if (strchr (new, old[i]))
j++;
if (i >= j * 2)
return 0;
return 1;
}
/*
* a nice mix of characters.
*/
/*ARGSUSED*/ static int simple (const char *old, const char *new)
{
int digits = 0;
int uppers = 0;
int lowers = 0;
int others = 0;
int size;
int i;
for (i = 0; new[i]; i++) {
if (isdigit (new[i]))
digits++;
else if (isupper (new[i]))
uppers++;
else if (islower (new[i]))
lowers++;
else
others++;
}
/*
* The scam is this - a password of only one character type
* must be 8 letters long. Two types, 7, and so on.
*/
size = 9;
if (digits)
size--;
if (uppers)
size--;
if (lowers)
size--;
if (others)
size--;
if (size <= i)
return 0;
return 1;
}
static char *str_lower (char *string)
{
char *cp;
for (cp = string; *cp; cp++)
*cp = tolower (*cp);
return string;
}
static const char *password_check (const char *old, const char *new,
const struct passwd *pwdp)
{
const char *msg = NULL;
char *oldmono, *newmono, *wrapped;
#ifdef HAVE_LIBCRACK
char *dictpath;
#ifdef HAVE_LIBCRACK_PW
char *FascistCheckPw ();
#else
char *FascistCheck ();
#endif
#endif
if (strcmp (new, old) == 0)
return "no change";
newmono = str_lower (xstrdup (new));
oldmono = str_lower (xstrdup (old));
wrapped = xmalloc (strlen (oldmono) * 2 + 1);
strcpy (wrapped, oldmono);
strcat (wrapped, oldmono);
if (palindrome (oldmono, newmono))
msg = "a palindrome";
if (!msg && strcmp (oldmono, newmono) == 0)
msg = "case changes only";
if (!msg && similar (oldmono, newmono))
msg = "too similar";
if (!msg && simple (old, new))
msg = "too simple";
if (!msg && strstr (wrapped, newmono))
msg = "rotated";
#ifdef HAVE_LIBCRACK
/*
* Invoke Alec Muffett's cracklib routines.
*/
if (!msg && (dictpath = getdef_str ("CRACKLIB_DICTPATH")))
#ifdef HAVE_LIBCRACK_PW
msg = FascistCheckPw (new, dictpath, pwdp);
#else
msg = FascistCheck (new, dictpath);
#endif
#endif
strzero (newmono);
strzero (oldmono);
strzero (wrapped);
free (newmono);
free (oldmono);
free (wrapped);
return msg;
}
/*ARGSUSED*/
static const char *obscure_msg (const char *old, const char *new,
const struct passwd *pwdp)
{
int maxlen, oldlen, newlen;
char *new1, *old1;
const char *msg;
oldlen = strlen (old);
newlen = strlen (new);
if (newlen < getdef_num ("PASS_MIN_LEN", 0))
return "too short";
/*
* Remaining checks are optional.
*/
if (!getdef_bool ("OBSCURE_CHECKS_ENAB"))
return NULL;
msg = password_check (old, new, pwdp);
if (msg)
return msg;
/* The traditional crypt() truncates passwords to 8 chars. It is
possible to circumvent the above checks by choosing an easy
8-char password and adding some random characters to it...
Example: "password$%^&*123". So check it again, this time
truncated to the maximum length. Idea from npasswd. --marekm */
if (getdef_bool ("MD5_CRYPT_ENAB"))
return NULL; /* unlimited password length */
maxlen = getdef_num ("PASS_MAX_LEN", 8);
if (oldlen <= maxlen && newlen <= maxlen)
return NULL;
new1 = xstrdup (new);
old1 = xstrdup (old);
if (newlen > maxlen)
new1[maxlen] = '\0';
if (oldlen > maxlen)
old1[maxlen] = '\0';
msg = password_check (old1, new1, pwdp);
memzero (new1, newlen);
memzero (old1, oldlen);
free (new1);
free (old1);
return msg;
}
/*
* Obscure - see if password is obscure enough.
*
* The programmer is encouraged to add as much complexity to this
* routine as desired. Included are some of my favorite ways to
* check passwords.
*/
int obscure (const char *old, const char *new, const struct passwd *pwdp)
{
const char *msg = obscure_msg (old, new, pwdp);
if (msg) {
printf (_("Bad password: %s. "), msg);
return 0;
}
return 1;
}
#endif /* !USE_PAM */