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 tarball for details.
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.
49 static int string_checker_helper(const char *p1, const char *p2) __attribute__ ((__pure__));
51 static int string_checker_helper(const char *p1, const char *p2)
53 /* as-is or capitalized */
54 if (strcasecmp(p1, p2) == 0
56 || strcasestr(p2, p1) != NULL
57 /* invert in case haystack is shorter than needle */
58 || strcasestr(p1, p2) != NULL)
63 static int string_checker(const char *p1, const char *p2)
67 int ret = string_checker_helper(p1, p2);
68 /* Make our own copy */
69 char *p = bb_xstrdup(p1);
79 /* check reversed string */
80 ret |= string_checker_helper(p, p2);
82 memset(p, 0, strlen(p1));
92 static const char *obscure_msg(const char *old_p, const char *new_p, const struct passwd *pw)
98 /* Add 2 for each type of characters to the minlen of password */
99 int size = CONFIG_PASSWORD_MINLEN + 8;
104 if (!new_p || (length = strlen(new_p)) < CONFIG_PASSWORD_MINLEN)
107 /* no username as-is, as sub-string, reversed, capitalized, doubled */
108 if (string_checker(new_p, pw->pw_name)) {
109 return "similar to username";
111 /* no gecos as-is, as sub-string, reversed, capitalized, doubled */
112 if (string_checker(new_p, pw->pw_gecos)) {
113 return "similar to gecos";
115 /* hostname as-is, as sub-string, reversed, capitalized, doubled */
116 if (gethostname(hostname, 255) == 0) {
117 hostname[254] = '\0';
118 if (string_checker(new_p, hostname)) {
119 return "similar to hostname";
123 /* Should / Must contain a mix of: */
124 for (i = 0; i < length; i++) {
125 if (islower(new_p[i])) { /* a-z */
127 } else if (isupper(new_p[i])) { /* A-Z */
129 } else if (isdigit(new_p[i])) { /* 0-9 */
131 } else { /* special characters */
134 /* More than 50% similar characters ? */
138 if ((p = strchr(p, new_p[i])) == NULL) {
143 break; /* move past the matched char if possible */
147 if (c >= (length / 2)) {
148 return "too many similar characters";
152 if (mixed & (1<<i)) size -= 2;
156 if (old_p && old_p[0] != '\0') {
157 /* check vs. old password */
158 if (string_checker(new_p, old_p)) {
159 return "similar to old password";
165 int obscure(const char *old, const char *newval, const struct passwd *pwdp)
169 if ((msg = obscure_msg(old, newval, pwdp))) {
170 printf("Bad password: %s.\n", msg);
171 /* If user is root warn only */
172 return (getuid())? 1 : 0;