1 /* vi: set sw=4 ts=4: */
3 * Mini weak password checker implementation for busybox
5 * Copyright (C) 2006 Tito Ragusa <farmatito@tiscali.it>
7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
11 1) should contain at least six characters (man passwd);
12 2) empty passwords are not permitted;
13 3) should contain a mix of four different types of characters
17 special characters such as !@#$%^&*,;".
18 This password types should not be permitted:
19 a) pure numbers: birthdates, social security number, license plate, phone numbers;
20 b) words and all letters only passwords (uppercase, lowercase or mixed)
21 as palindromes, consecutive or repetitive letters
22 or adjacent letters on your keyboard;
23 c) username, real name, company name or (e-mail?) address
24 in any form (as-is, reversed, capitalized, doubled, etc.).
25 (we can check only against username, gecos and hostname)
26 d) common and obvious letter-number replacements
27 (e.g. replace the letter O with number 0)
28 such as "M1cr0$0ft" or "P@ssw0rd" (CAVEAT: we cannot check for them
29 without the use of a dictionary).
31 For each missing type of characters an increase of password length is
34 If user is root we warn only.
36 CAVEAT: some older versions of crypt() truncates passwords to 8 chars,
37 so that aaaaaaaa1Q$ is equal to aaaaaaaa making it possible to fool
38 some of our checks. We don't test for this special case as newer versions
39 of crypt do not truncate passwords.
44 static int string_checker_helper(const char *p1, const char *p2) __attribute__ ((__pure__));
46 static int string_checker_helper(const char *p1, const char *p2)
49 if (strcasestr(p2, p1) != NULL
50 /* invert in case haystack is shorter than needle */
51 || strcasestr(p1, p2) != NULL
52 /* as-is or capitalized */
53 /* || strcasecmp(p1, p2) == 0 - 1st strcasestr should catch this too */
60 static int string_checker(const char *p1, const char *p2)
64 int ret = string_checker_helper(p1, p2);
65 /* make our own copy */
66 char *p = xstrdup(p1);
69 i = size = strlen(p1);
73 p -= size; /* restore pointer */
75 /* check reversed string */
76 ret |= string_checker_helper(p, p2);
94 static const char *obscure_msg(const char *old_p, const char *new_p, const struct passwd *pw)
105 if (!new_p || (length = strlen(new_p)) < CONFIG_PASSWORD_MINLEN)
108 /* no username as-is, as sub-string, reversed, capitalized, doubled */
109 if (string_checker(new_p, pw->pw_name)) {
110 return "similar to username";
112 /* no gecos as-is, as sub-string, reversed, capitalized, doubled */
113 if (pw->pw_gecos[0] && string_checker(new_p, pw->pw_gecos)) {
114 return "similar to gecos";
116 /* hostname as-is, as sub-string, reversed, capitalized, doubled */
117 hostname = safe_gethostname();
118 i = string_checker(new_p, hostname);
121 return "similar to hostname";
123 /* Should / Must contain a mix of: */
125 for (i = 0; i < length; i++) {
126 if (islower(new_p[i])) { /* a-z */
128 } else if (isupper(new_p[i])) { /* A-Z */
130 } else if (isdigit(new_p[i])) { /* 0-9 */
132 } else { /* special characters */
135 /* Count i'th char */
139 p = strchr(p, new_p[i]);
149 /* More than 50% similar characters ? */
151 return "too many similar characters";
155 size = CONFIG_PASSWORD_MINLEN + 2*CATEGORIES;
156 for (i = 1; i <= LAST_CAT; i <<= 1)
162 if (old_p && old_p[0]) {
163 /* check vs. old password */
164 if (string_checker(new_p, old_p)) {
165 return "similar to old password";
172 int FAST_FUNC obscure(const char *old, const char *newval, const struct passwd *pw)
176 msg = obscure_msg(old, newval, pw);
178 printf("Bad password: %s\n", msg);