busybox/libbb/obscure.c

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/* vi: set sw=4 ts=4: */
/*
* Copyright 1989 - 1994, Julianne Frances Haugh <jockgrrl@austin.rr.com>
* Copyright 2006, Bernhard Fischer <busybox@busybox.net>
* 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.
*/
/*
* 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 <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include "libbb.h"
/*
* can't be a palindrome - like `R A D A R' or `M A D A M'
*/
static int palindrome(const char *newval)
{
int i, j;
i = strlen(newval);
for (j = 0; j < i; j++)
if (newval[i - j - 1] != newval[j])
return 0;
return 1;
}
/*
* more than half of the characters are different ones.
*/
static int similiar(const char *old, const char *newval)
{
int i, j;
for (i = j = 0; newval[i] && old[i]; i++)
if (strchr(newval, old[i]))
j++;
if (i >= j * 2)
return 0;
return 1;
}
/*
* a nice mix of characters.
*/
static int simple(const char *newval)
{
#define digits 1
#define uppers 2
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#define lowers 4
#define others 8
int c, is_simple = 0;
int size;
int i;
for (i = 0; (c = *newval++) != 0; i++) {
if (isdigit(c))
is_simple |= digits;
else if (isupper(c))
is_simple |= uppers;
else if (islower(c))
is_simple |= lowers;
else
is_simple |= 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 (is_simple & digits)
size--;
if (is_simple & uppers)
size--;
if (is_simple & lowers)
size--;
if (is_simple & others)
size--;
if (size <= i)
return 0;
return 1;
#undef digits
#undef uppers
#undef lowers
#undef others
}
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 *newval, const struct passwd *pwdp)
{
const char *msg;
char *newmono, *wrapped;
int lenwrap;
if (strcmp(newval, old) == 0)
return "no change";
if (simple(newval))
return "too simple";
msg = NULL;
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newmono = str_lower(bb_xstrdup(newval));
lenwrap = strlen(old);
wrapped = (char *) xmalloc(lenwrap * 2 + 1);
str_lower(strcpy(wrapped, old));
if (palindrome(newmono))
msg = "a palindrome";
else if (strcmp(wrapped, newmono) == 0)
msg = "case changes only";
else if (similiar(wrapped, newmono))
msg = "too similiar";
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else if ( strstr(newval, pwdp->pw_name) )
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msg = "username in password";
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else {
safe_strncpy(wrapped + lenwrap, wrapped, lenwrap + 1);
if (strstr(wrapped, newmono))
msg = "rotated";
}
memset(newmono, 0, strlen(newmono));
memset(wrapped, 0, lenwrap * 2);
free(newmono);
free(wrapped);
return msg;
}
static const char *
obscure_msg(const char *old, const char *newval, const struct passwd *pwdp)
{
int maxlen, oldlen, newlen;
char *new1, *old1;
const char *msg;
oldlen = strlen(old);
newlen = strlen(newval);
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#if 0 /* why not check the password when set for the first time? --marekm */
if (old[0] == '\0')
/* return (1); */
return NULL;
#endif
if (newlen < 5)
return "too short";
/*
* Remaining checks are optional.
*/
/* Not for us -- Sean
*if (!getdef_bool("OBSCURE_CHECKS_ENAB"))
* return NULL;
*/
msg = password_check(old, newval, 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 */
maxlen = 8;
if (oldlen <= maxlen && newlen <= maxlen)
return NULL;
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new1 = (char *) bb_xstrdup(newval);
old1 = (char *) bb_xstrdup(old);
if (newlen > maxlen)
new1[maxlen] = '\0';
if (oldlen > maxlen)
old1[maxlen] = '\0';
msg = password_check(old1, new1, pwdp);
memset(new1, 0, newlen);
memset(old1, 0, 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.
*/
extern int obscure(const char *old, const char *newval, const struct passwd *pwdp)
{
const char *msg = obscure_msg(old, newval, pwdp);
/* if (msg) { */
if (msg != NULL) {
printf("Bad password: %s.\n", msg);
/* return 0; */
return 1;
}
/* return 1; */
return 0;
}