New version from Tito.

1 files changed, 144 insertions, 224 deletions

diff --git a/libbb/obscure.c b/libbb/obscure.c
index 6244970de..a152456b2 100644
--- a/libbb/obscure.c
+++ b/libbb/obscure.c
@@ -1,259 +1,179 @@
 /* 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.
+ * Mini weak password checker implementation for busybox
  *
- * 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.
+ * Copyright (C) 2006 Tito Ragusa <farmatito@tiscali.it>
  *
- * 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.
+ * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  */
 
-/*
- * 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.
- */
+/*      A good password:
+        1)      should contain at least six characters (man passwd);
+        2)      empty passwords are not permitted;
+        3)      should contain a mix of four different types of characters
+                upper case letters,
+                lower case letters,
+                numbers,
+                special characters such as !@#$%^&*,;".
+        This password types should not  be permitted:
+        a)      pure numbers: birthdates, social security number, license plate, phone numbers;
+        b)      words and all letters only passwords (uppercase, lowercase or mixed)
+                as palindromes, consecutive or repetitive letters 
+                or adjacent letters on your keyboard;
+        c)      username, real name, company name or (e-mail?) address
+                in any form (as-is, reversed, capitalized, doubled, etc.).
+                (we can check only against username, gecos and hostname)
+        d)      common and obvious letter-number replacements 
+                (e.g. replace the letter O with number 0)
+                such as "M1cr0$0ft" or "P@ssw0rd" (CAVEAT: we cannot check for them
+                without the use of a dictionary).
+
+        For each missing type of characters an increase of password length is
+        requested.
+
+        If user is root we warn only.
+
+        CAVEAT: some older versions of crypt() truncates passwords to 8 chars,
+        so that aaaaaaaa1Q$ is equal to aaaaaaaa making it possible to fool
+        some of our checks. We don't test for this special case as newer versions
+        of crypt do not truncate passwords.
+*/
 
-#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'
- */
+#include <unistd.h>
+#include <string.h>
 
-static int palindrome(const char *newval)
-{
-        int i, j;
+#include "libbb.h"
 
-        i = strlen(newval);
 
-        for (j = 0; j < i; j++)
-                if (newval[i - j - 1] != newval[j])
-                        return 0;
+/* passwords should consist of 6 (to 8 characters) */
+#define MINLEN 6 
 
-        return 1;
-}
 
-/*
- * more than half of the characters are different ones.
- */
+static int string_checker_helper(const char *p1, const char *p2) __attribute__ ((__pure__));
 
-static int similiar(const char *old, const char *newval)
+static int string_checker_helper(const char *p1, const char *p2)
 {
-        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;
+        /* as-is or capitalized */
+        if (strcasecmp(p1, p2) == 0
+        /* as sub-string */
+        || strcasestr(p2, p1) != NULL
+        /* invert in case haystack is shorter than needle */
+        || strcasestr(p1, p2) != NULL)
+                return 1;
+        return 0;
 }
 
-/*
- * a nice mix of characters.
- */
-
-static int simple(const char *newval)
+static int string_checker(const char *p1, const char *p2)
 {
-#define digits 1
-#define uppers 2
-#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;
+        /* check string */
+        int ret = string_checker_helper(p1, p2);
+        /* Make our own copy */
+        char *p = bb_xstrdup(p1);
+        /* reverse string */
+        size = strlen(p);
+
+        while (size--) {
+                *p = p1[size];
+                p++;
         }
-
-        /*
-         * 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
+        /* restore pointer */
+        p -= strlen(p1);
+        /* check reversed string */
+        ret |= string_checker_helper(p, p2);
+        /* clean up */
+        memset(p, 0, strlen(p1));
+        free(p);
+        return ret;
 }
 
-static char *str_lower(char *string)
-{
-        char *cp;
-
-        for (cp = string; *cp; cp++)
-                *cp = tolower(*cp);
-        return string;
-}
+#define LOWERCASE          1
+#define UPPERCASE          2
+#define NUMBERS            4
+#define SPECIAL            8
 
-static const char *
-password_check(const char *old, const char *newval, const struct passwd *pwdp)
+static const char *obscure_msg(const char *old_p, const char *new_p, const struct passwd *pw) 
 {
-        const char *msg;
-        char *newmono, *wrapped;
-        int lenwrap;
-
-        if (strcmp(newval, old) == 0)
-                return "no change";
-        if (simple(newval))
-                return "too simple";
-
-        msg = NULL;
-        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";
-
-        else if ( strstr(newval, pwdp->pw_name) )
-                msg = "username in password";
-
-        else {
-                safe_strncpy(wrapped + lenwrap, wrapped, lenwrap + 1);
-                if (strstr(wrapped, newmono))
-                        msg = "rotated";
+        int i;
+        int c;
+        int length;
+        int mixed = 0;
+        /* Add 1 for each type of characters to the minlen of password */
+        int size = MINLEN + 8;
+        const char *p;
+        char hostname[255];
+
+        /* size */
+        if (!new_p || (length = strlen(new_p)) < MINLEN)
+                return("too short");
+        
+        /* no username as-is, as sub-string, reversed, capitalized, doubled */
+        if (string_checker(new_p, pw->pw_name)) {
+                return "similar to username";
+        }
+        /* no gecos as-is, as sub-string, reversed, capitalized, doubled */
+        if (string_checker(new_p, pw->pw_gecos)) {
+                return "similar to gecos";
+        }
+        /* hostname as-is, as sub-string, reversed, capitalized, doubled */
+        if (gethostname(hostname, 255) == 0) {
+                hostname[254] = '\0';
+                if (string_checker(new_p, hostname)) {
+                        return "similar to hostname";
+                }
         }
 
-        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);
-
-#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;
-
-        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;
+        /* Should / Must contain a mix of: */
+        for (i = 0; i < length; i++) {
+                if (islower(new_p[i])) {        /* a-z */
+                        mixed |= LOWERCASE;
+                } else if (isupper(new_p[i])) { /* A-Z */
+                        mixed |= UPPERCASE;
+                } else if (isdigit(new_p[i])) { /* 0-9 */
+                        mixed |= NUMBERS;
+                } else  {                       /* special characters */
+                        mixed |= SPECIAL;
+                }
+                /* More than 50% similar characters ? */
+                c = 0;
+                p = new_p;
+                while (1) {
+                        if ((p = strchr(p, new_p[i])) == NULL) {
+                                break;
+                        }
+                        c++;
+                        if (!++p) {
+                                break; /* move past the matched char if possible */
+                        }
+                }
+
+                if (c >= (length / 2)) {
+                        return "too many similar characters";
+                }
+        }
+        for(i=0;i<4;i++)
+                if (mixed & (1<<i)) size -= 2;
+        if (length < size)
+                return "too weak";
+        
+        if (old_p && old_p[0] != '\0') {
+                /* check vs. old password */
+                if (string_checker(new_p, old_p)) {
+                        return "similar to old password";
+                }
+        }
+        return NULL;
 }
 
-/*
- * 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 *newval, const struct passwd *pwdp)
 {
-        const char *msg = obscure_msg(old, newval, pwdp);
+        const char *msg;
 
-        /*  if (msg) { */
-        if (msg != NULL) {
+        if ((msg = obscure_msg(old, newval, pwdp))) {
                 printf("Bad password: %s.\n", msg);
-                /* return 0; */
-                return 1;
+                /* If user is root warn only */
+                return (getuid())? 1 : 0;
         }
-        /* return 1; */
         return 0;
 }