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";
113 /* no gecos as-is, as sub-string, reversed, capitalized, doubled */
114 if (pw->pw_gecos[0] && string_checker(new_p, pw->pw_gecos)) {
115 return "similar to gecos";
118 /* hostname as-is, as sub-string, reversed, capitalized, doubled */
119 hostname = safe_gethostname();
120 i = string_checker(new_p, hostname);
123 return "similar to hostname";
125 /* Should / Must contain a mix of: */
127 for (i = 0; i < length; i++) {
128 if (islower(new_p[i])) { /* a-z */
130 } else if (isupper(new_p[i])) { /* A-Z */
132 } else if (isdigit(new_p[i])) { /* 0-9 */
134 } else { /* special characters */
137 /* Count i'th char */
141 p = strchr(p, new_p[i]);
151 /* More than 50% similar characters ? */
153 return "too many similar characters";
157 size = CONFIG_PASSWORD_MINLEN + 2*CATEGORIES;
158 for (i = 1; i <= LAST_CAT; i <<= 1)
164 if (old_p && old_p[0]) {
165 /* check vs. old password */
166 if (string_checker(new_p, old_p)) {
167 return "similar to old password";
174 int FAST_FUNC obscure(const char *old, const char *newval, const struct passwd *pw)
178 msg = obscure_msg(old, newval, pw);
180 printf("Bad password: %s\n", msg);
188 /* Test obscure_msg() instead of obscure() in order not to print anything. */
190 static const struct passwd pw = {
191 .pw_name = (char *)"johndoe",
192 .pw_gecos = (char *)"John Doe",
195 BBUNIT_DEFINE_TEST(obscure_weak_pass)
198 BBUNIT_ASSERT_NOTNULL(obscure_msg("Ad4#21?'S|", "", &pw));
200 BBUNIT_ASSERT_NOTNULL(obscure_msg("Ad4#21?'S|", "23577315", &pw));
201 /* Similar to pw_name */
202 BBUNIT_ASSERT_NOTNULL(obscure_msg("Ad4#21?'S|", "johndoe123%", &pw));
203 /* Similar to pw_gecos, reversed */
204 BBUNIT_ASSERT_NOTNULL(obscure_msg("Ad4#21?'S|", "eoD nhoJ^44@", &pw));
205 /* Similar to the old password */
206 BBUNIT_ASSERT_NOTNULL(obscure_msg("Ad4#21?'S|", "d4#21?'S", &pw));
207 /* adjacent letters */
208 BBUNIT_ASSERT_NOTNULL(obscure_msg("Ad4#21?'S|", "qwerty123", &pw));
209 /* Many similar chars */
210 BBUNIT_ASSERT_NOTNULL(obscure_msg("Ad4#21?'S|", "^33Daaaaaa1", &pw));
215 BBUNIT_DEFINE_TEST(obscure_strong_pass)
217 BBUNIT_ASSERT_NULL(obscure_msg("Rt4##2&:'|", "}(^#rrSX3S*22", &pw));
222 #endif /* ENABLE_UNIT_TEST */