shadow/libmisc/obscure.c

287 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>
#include "rcsid.h"
RCSID("$Id: obscure.c,v 1.9 1999/03/07 19:14:40 marekm 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 0 /* why not check the password when set for the first time? --marekm */
if (old[0] == '\0')
return NULL;
#endif
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;
}