shadow/libmisc/obscure.c
nekral-guest 4d606cc690 * configure.in: New configure option: --with-sha-crypt enabled by
default. Keeping the feature enabled is safe. Disabling it permits
  to disable the references to the SHA256 and SHA512 password
  encryption algorithms from the usage help and manuals (in addition
  to the support for these algorithms in the code).
* libmisc/obscure.c, libmisc/salt.c, src/newusers.c,
  src/chpasswd.c, src/chgpasswd.c, src/passwd.c: ENCRYPT_METHOD is
  always supported in login.defs. Remove the ENCRYPTMETHOD_SELECT
  preprocessor condition.
* libmisc/obscure.c, libmisc/salt.c, src/newusers.c,
  src/chpasswd.c, src/chgpasswd.c, src/passwd.c: Disable SHA256 and
  SHA512 if USE_SHA_CRYPT is not defined (this corresponds to a
  subset of the ENCRYPTMETHOD_SELECT sections).
2007-11-24 13:08:08 +00:00

293 lines
6.5 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
#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'
*/
/*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;
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 (msg)
return msg;
if ((result = getdef_str ("ENCRYPT_METHOD")) == NULL) {
/* 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")
#ifdef USE_SHA_CRYPT
|| !strcmp (result, "SHA256")
|| !strcmp (result, "SHA512")
#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 (msg) {
printf (_("Bad password: %s. "), msg);
return 0;
}
return 1;
}
#endif /* !USE_PAM */