New version from Tito.
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Rob Landley
parent
819b56b64a
commit
a13cca9cf4
376
libbb/obscure.c
376
libbb/obscure.c
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/* vi: set sw=4 ts=4: */
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/*
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* Copyright 1989 - 1994, Julianne Frances Haugh <jockgrrl@austin.rr.com>
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* Copyright 2006, Bernhard Fischer <busybox@busybox.net>
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* All rights reserved.
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* Mini weak password checker implementation for busybox
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of Julianne F. Haugh nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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* Copyright (C) 2006 Tito Ragusa <farmatito@tiscali.it>
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*
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* THIS SOFTWARE IS PROVIDED BY JULIE HAUGH AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL JULIE HAUGH OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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*/
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/*
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* This version of obscure.c contains modifications to support "cracklib"
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* by Alec Muffet (alec.muffett@uk.sun.com). You must obtain the Cracklib
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* library source code for this function to operate.
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*/
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/* A good password:
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1) should contain at least six characters (man passwd);
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2) empty passwords are not permitted;
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3) should contain a mix of four different types of characters
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upper case letters,
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lower case letters,
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numbers,
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special characters such as !@#$%^&*,;".
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This password types should not be permitted:
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a) pure numbers: birthdates, social security number, license plate, phone numbers;
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b) words and all letters only passwords (uppercase, lowercase or mixed)
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as palindromes, consecutive or repetitive letters
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or adjacent letters on your keyboard;
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c) username, real name, company name or (e-mail?) address
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in any form (as-is, reversed, capitalized, doubled, etc.).
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(we can check only against username, gecos and hostname)
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d) common and obvious letter-number replacements
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(e.g. replace the letter O with number 0)
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such as "M1cr0$0ft" or "P@ssw0rd" (CAVEAT: we cannot check for them
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without the use of a dictionary).
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For each missing type of characters an increase of password length is
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requested.
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If user is root we warn only.
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CAVEAT: some older versions of crypt() truncates passwords to 8 chars,
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so that aaaaaaaa1Q$ is equal to aaaaaaaa making it possible to fool
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some of our checks. We don't test for this special case as newer versions
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of crypt do not truncate passwords.
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*/
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <ctype.h>
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#include <unistd.h>
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#include <string.h>
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#include "libbb.h"
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/*
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* can't be a palindrome - like `R A D A R' or `M A D A M'
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*/
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static int palindrome(const char *newval)
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/* passwords should consist of 6 (to 8 characters) */
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#define MINLEN 6
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static int string_checker_helper(const char *p1, const char *p2) __attribute__ ((__pure__));
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static int string_checker_helper(const char *p1, const char *p2)
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{
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int i, j;
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i = strlen(newval);
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for (j = 0; j < i; j++)
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if (newval[i - j - 1] != newval[j])
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return 0;
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return 1;
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/* as-is or capitalized */
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if (strcasecmp(p1, p2) == 0
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/* as sub-string */
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|| strcasestr(p2, p1) != NULL
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/* invert in case haystack is shorter than needle */
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|| strcasestr(p1, p2) != NULL)
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return 1;
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return 0;
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}
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/*
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* more than half of the characters are different ones.
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*/
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static int similiar(const char *old, const char *newval)
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static int string_checker(const char *p1, const char *p2)
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{
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int i, j;
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for (i = j = 0; newval[i] && old[i]; i++)
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if (strchr(newval, old[i]))
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j++;
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if (i >= j * 2)
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return 0;
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return 1;
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}
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/*
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* a nice mix of characters.
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*/
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static int simple(const char *newval)
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{
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#define digits 1
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#define uppers 2
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#define lowers 4
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#define others 8
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int c, is_simple = 0;
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int size;
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/* check string */
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int ret = string_checker_helper(p1, p2);
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/* Make our own copy */
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char *p = bb_xstrdup(p1);
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/* reverse string */
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size = strlen(p);
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while (size--) {
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*p = p1[size];
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p++;
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}
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/* restore pointer */
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p -= strlen(p1);
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/* check reversed string */
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ret |= string_checker_helper(p, p2);
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/* clean up */
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memset(p, 0, strlen(p1));
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free(p);
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return ret;
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}
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#define LOWERCASE 1
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#define UPPERCASE 2
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#define NUMBERS 4
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#define SPECIAL 8
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static const char *obscure_msg(const char *old_p, const char *new_p, const struct passwd *pw)
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{
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int i;
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int c;
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int length;
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int mixed = 0;
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/* Add 1 for each type of characters to the minlen of password */
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int size = MINLEN + 8;
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const char *p;
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char hostname[255];
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for (i = 0; (c = *newval++) != 0; i++) {
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if (isdigit(c))
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is_simple |= digits;
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else if (isupper(c))
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is_simple |= uppers;
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else if (islower(c))
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is_simple |= lowers;
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else
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is_simple |= others;
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/* size */
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if (!new_p || (length = strlen(new_p)) < MINLEN)
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return("too short");
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/* no username as-is, as sub-string, reversed, capitalized, doubled */
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if (string_checker(new_p, pw->pw_name)) {
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return "similar to username";
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}
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/* no gecos as-is, as sub-string, reversed, capitalized, doubled */
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if (string_checker(new_p, pw->pw_gecos)) {
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return "similar to gecos";
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}
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/* hostname as-is, as sub-string, reversed, capitalized, doubled */
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if (gethostname(hostname, 255) == 0) {
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hostname[254] = '\0';
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if (string_checker(new_p, hostname)) {
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return "similar to hostname";
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}
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}
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/*
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* The scam is this - a password of only one character type
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* must be 8 letters long. Two types, 7, and so on.
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*/
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/* Should / Must contain a mix of: */
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for (i = 0; i < length; i++) {
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if (islower(new_p[i])) { /* a-z */
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mixed |= LOWERCASE;
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} else if (isupper(new_p[i])) { /* A-Z */
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mixed |= UPPERCASE;
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} else if (isdigit(new_p[i])) { /* 0-9 */
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mixed |= NUMBERS;
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} else { /* special characters */
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mixed |= SPECIAL;
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}
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/* More than 50% similar characters ? */
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c = 0;
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p = new_p;
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while (1) {
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if ((p = strchr(p, new_p[i])) == NULL) {
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break;
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}
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c++;
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if (!++p) {
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break; /* move past the matched char if possible */
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}
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}
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size = 9;
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if (is_simple & digits)
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size--;
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if (is_simple & uppers)
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size--;
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if (is_simple & lowers)
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size--;
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if (is_simple & others)
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size--;
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if (size <= i)
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return 0;
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return 1;
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#undef digits
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#undef uppers
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#undef lowers
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#undef others
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}
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static char *str_lower(char *string)
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{
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char *cp;
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for (cp = string; *cp; cp++)
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*cp = tolower(*cp);
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return string;
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}
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static const char *
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password_check(const char *old, const char *newval, const struct passwd *pwdp)
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{
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const char *msg;
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char *newmono, *wrapped;
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int lenwrap;
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if (strcmp(newval, old) == 0)
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return "no change";
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if (simple(newval))
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return "too simple";
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msg = NULL;
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newmono = str_lower(bb_xstrdup(newval));
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lenwrap = strlen(old);
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wrapped = (char *) xmalloc(lenwrap * 2 + 1);
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str_lower(strcpy(wrapped, old));
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if (palindrome(newmono))
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msg = "a palindrome";
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else if (strcmp(wrapped, newmono) == 0)
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msg = "case changes only";
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else if (similiar(wrapped, newmono))
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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 {
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safe_strncpy(wrapped + lenwrap, wrapped, lenwrap + 1);
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if (strstr(wrapped, newmono))
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msg = "rotated";
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if (c >= (length / 2)) {
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return "too many similar characters";
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}
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}
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memset(newmono, 0, strlen(newmono));
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memset(wrapped, 0, lenwrap * 2);
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free(newmono);
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free(wrapped);
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return msg;
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for(i=0;i<4;i++)
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if (mixed & (1<<i)) size -= 2;
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if (length < size)
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return "too weak";
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if (old_p && old_p[0] != '\0') {
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/* check vs. old password */
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if (string_checker(new_p, old_p)) {
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return "similar to old password";
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}
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}
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return NULL;
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}
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static const char *
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obscure_msg(const char *old, const char *newval, const struct passwd *pwdp)
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{
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int maxlen, oldlen, newlen;
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char *new1, *old1;
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const char *msg;
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oldlen = strlen(old);
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newlen = strlen(newval);
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#if 0 /* why not check the password when set for the first time? --marekm */
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if (old[0] == '\0')
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/* return (1); */
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return NULL;
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#endif
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if (newlen < 5)
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return "too short";
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/*
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* Remaining checks are optional.
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*/
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/* Not for us -- Sean
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*if (!getdef_bool("OBSCURE_CHECKS_ENAB"))
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* return NULL;
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*/
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msg = password_check(old, newval, pwdp);
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if (msg)
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return msg;
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/* The traditional crypt() truncates passwords to 8 chars. It is
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possible to circumvent the above checks by choosing an easy
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8-char password and adding some random characters to it...
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Example: "password$%^&*123". So check it again, this time
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truncated to the maximum length. Idea from npasswd. --marekm */
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maxlen = 8;
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if (oldlen <= maxlen && newlen <= maxlen)
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return NULL;
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new1 = (char *) bb_xstrdup(newval);
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old1 = (char *) bb_xstrdup(old);
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if (newlen > maxlen)
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new1[maxlen] = '\0';
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if (oldlen > maxlen)
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old1[maxlen] = '\0';
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msg = password_check(old1, new1, pwdp);
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memset(new1, 0, newlen);
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memset(old1, 0, oldlen);
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free(new1);
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free(old1);
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return msg;
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}
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/*
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* Obscure - see if password is obscure enough.
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*
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* The programmer is encouraged to add as much complexity to this
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* routine as desired. Included are some of my favorite ways to
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* check passwords.
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*/
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int obscure(const char *old, const char *newval, const struct passwd *pwdp)
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{
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const char *msg = obscure_msg(old, newval, pwdp);
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const char *msg;
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/* if (msg) { */
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if (msg != NULL) {
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if ((msg = obscure_msg(old, newval, pwdp))) {
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printf("Bad password: %s.\n", msg);
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/* return 0; */
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return 1;
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/* If user is root warn only */
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return (getuid())? 1 : 0;
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}
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/* return 1; */
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return 0;
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}
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