shadow/libmisc/obscure.c

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/*
* Copyright (c) 1989 - 1994, Julianne Frances Haugh
* Copyright (c) 1996 - 1999, Marek Michałkiewicz
* Copyright (c) 2003 - 2005, Tomasz Kłoczko
* Copyright (c) 2007 - 2008, Nicolas François
* 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 copyright holders or contributors may not be used to
* endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 THE COPYRIGHT
* HOLDERS 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
#ident "$Id$"
/*
* 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'
*/
static bool palindrome (unused 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 false;
}
}
return true;
}
/*
* more than half of the characters are different ones.
*/
static bool 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 false;
}
for (i = j = 0; ('\0' != new[i]) && ('\0' != old[i]); i++) {
if (strchr (new, old[i]) != NULL) {
j++;
}
}
if (i >= j * 2) {
return false;
}
return true;
}
/*
* a nice mix of characters.
*/
static int simple (unused const char *old, const char *new)
{
bool digits = false;
bool uppers = false;
bool lowers = false;
bool others = false;
int size;
int i;
for (i = 0; '\0' != new[i]; i++) {
if (isdigit (new[i])) {
digits = true;
} else if (isupper (new[i])) {
uppers = true;
} else if (islower (new[i])) {
lowers = true;
} else {
others = true;
}
}
/*
* 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 false;
}
return true;
}
static char *str_lower (char *string)
{
char *cp;
for (cp = string; '\0' != *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");
} else if (strcmp (oldmono, newmono) == 0) {
msg = _("case changes only");
} else if (similar (oldmono, newmono)) {
msg = _("too similar");
} else if (simple (old, new)) {
msg = _("too simple");
} else if (strstr (wrapped, newmono) != NULL) {
msg = _("rotated");
} else {
#ifdef HAVE_LIBCRACK
/*
* Invoke Alec Muffett's cracklib routines.
*/
dictpath = getdef_str ("CRACKLIB_DICTPATH");
if (NULL != 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;
char *result;
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 (NULL != msg) {
return msg;
}
result = getdef_str ("ENCRYPT_METHOD");
if (NULL == result) {
/* 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;
}
} else {
if ( (strcmp (result, "MD5") == 0)
#ifdef USE_SHA_CRYPT
|| (strcmp (result, "SHA256") == 0)
|| (strcmp (result, "SHA512") == 0)
#endif
) {
return NULL;
}
}
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 (NULL != msg) {
printf (_("Bad password: %s. "), msg);
return 0;
}
return 1;
}
#else /* !USE_PAM */
extern int errno; /* warning: ANSI C forbids an empty source file */
#endif /* !USE_PAM */