Index: pam.debian/modules/pam_unix/pam_unix_passwd.c =================================================================== --- pam.debian.orig/modules/pam_unix/pam_unix_passwd.c +++ pam.debian/modules/pam_unix/pam_unix_passwd.c @@ -102,6 +102,9 @@ # endif /* GNU libc 2.1 */ #endif +extern const char *obscure_msg(const char *, const char *, const struct passwd *, + unsigned int); + /* How it works: Gets in username (has to be done) from the calling program @@ -521,6 +524,11 @@ return retval; } } + if (!remark && pass_old != NULL) { /* only check if we don't already have a failure */ + struct passwd *pwd; + pwd = pam_modutil_getpwnam(pamh, user); + remark = (char *)obscure_msg(pass_old,pass_new,pwd,ctrl); /* do obscure checks */ + } } if (remark) { _make_remark(pamh, ctrl, PAM_ERROR_MSG, remark); @@ -536,7 +544,7 @@ int retval; int remember = -1; int rounds = -1; - int pass_min_len = 0; + int pass_min_len = 6; /* */ const char *user; Index: pam.debian/modules/pam_unix/support.h =================================================================== --- pam.debian.orig/modules/pam_unix/support.h +++ pam.debian/modules/pam_unix/support.h @@ -97,8 +97,9 @@ password hash algorithms */ #define UNIX_BLOWFISH_PASS 26 /* new password hashes will use blowfish */ #define UNIX_MIN_PASS_LEN 27 /* min length for password */ +#define UNIX_OBSCURE_CHECKS 28 /* enable obscure checks on passwords */ /* -------------- */ -#define UNIX_CTRLS_ 28 /* number of ctrl arguments defined */ +#define UNIX_CTRLS_ 29 /* number of ctrl arguments defined */ #define UNIX_DES_CRYPT(ctrl) (off(UNIX_MD5_PASS,ctrl)&&off(UNIX_BIGCRYPT,ctrl)&&off(UNIX_SHA256_PASS,ctrl)&&off(UNIX_SHA512_PASS,ctrl)&&off(UNIX_BLOWFISH_PASS,ctrl)) @@ -107,34 +108,35 @@ /* symbol token name ctrl mask ctrl * * ----------------------- ------------------- --------------------- -------- */ -/* UNIX__OLD_PASSWD */ {NULL, _ALL_ON_, 01, 0}, -/* UNIX__VERIFY_PASSWD */ {NULL, _ALL_ON_, 02, 0}, -/* UNIX__IAMROOT */ {NULL, _ALL_ON_, 04, 0}, -/* UNIX_AUDIT */ {"audit", _ALL_ON_, 010, 0}, -/* UNIX_USE_FIRST_PASS */ {"use_first_pass", _ALL_ON_^(060), 020, 0}, -/* UNIX_TRY_FIRST_PASS */ {"try_first_pass", _ALL_ON_^(060), 040, 0}, -/* UNIX_NOT_SET_PASS */ {"not_set_pass", _ALL_ON_, 0100, 0}, -/* UNIX__PRELIM */ {NULL, _ALL_ON_^(0600), 0200, 0}, -/* UNIX__UPDATE */ {NULL, _ALL_ON_^(0600), 0400, 0}, -/* UNIX__NONULL */ {NULL, _ALL_ON_, 01000, 0}, -/* UNIX__QUIET */ {NULL, _ALL_ON_, 02000, 0}, -/* UNIX_USE_AUTHTOK */ {"use_authtok", _ALL_ON_, 04000, 0}, -/* UNIX_SHADOW */ {"shadow", _ALL_ON_, 010000, 0}, -/* UNIX_MD5_PASS */ {"md5", _ALL_ON_^(0260420000), 020000, 1}, -/* UNIX__NULLOK */ {"nullok", _ALL_ON_^(01000), 0, 0}, -/* UNIX_DEBUG */ {"debug", _ALL_ON_, 040000, 0}, -/* UNIX_NODELAY */ {"nodelay", _ALL_ON_, 0100000, 0}, -/* UNIX_NIS */ {"nis", _ALL_ON_, 0200000, 0}, -/* UNIX_BIGCRYPT */ {"bigcrypt", _ALL_ON_^(0260420000), 0400000, 1}, -/* UNIX_LIKE_AUTH */ {"likeauth", _ALL_ON_, 01000000, 0}, -/* UNIX_REMEMBER_PASSWD */ {"remember=", _ALL_ON_, 02000000, 0}, -/* UNIX_NOREAP */ {"noreap", _ALL_ON_, 04000000, 0}, -/* UNIX_BROKEN_SHADOW */ {"broken_shadow", _ALL_ON_, 010000000, 0}, -/* UNIX_SHA256_PASS */ {"sha256", _ALL_ON_^(0260420000), 020000000, 1}, -/* UNIX_SHA512_PASS */ {"sha512", _ALL_ON_^(0260420000), 040000000, 1}, -/* UNIX_ALGO_ROUNDS */ {"rounds=", _ALL_ON_, 0100000000, 0}, -/* UNIX_BLOWFISH_PASS */ {"blowfish", _ALL_ON_^(0260420000), 0200000000, 1}, -/* UNIX_MIN_PASS_LEN */ {"minlen=", _ALL_ON_, 0400000000, 0}, +/* UNIX__OLD_PASSWD */ {NULL, _ALL_ON_, 0x1, 0}, +/* UNIX__VERIFY_PASSWD */ {NULL, _ALL_ON_, 0x2, 0}, +/* UNIX__IAMROOT */ {NULL, _ALL_ON_, 0x4, 0}, +/* UNIX_AUDIT */ {"audit", _ALL_ON_, 0x8, 0}, +/* UNIX_USE_FIRST_PASS */ {"use_first_pass", _ALL_ON_^(0x30), 0x10, 0}, +/* UNIX_TRY_FIRST_PASS */ {"try_first_pass", _ALL_ON_^(0x30), 0x20, 0}, +/* UNIX_NOT_SET_PASS */ {"not_set_pass", _ALL_ON_, 0x40, 0}, +/* UNIX__PRELIM */ {NULL, _ALL_ON_^(0x180), 0x80, 0}, +/* UNIX__UPDATE */ {NULL, _ALL_ON_^(0x180), 0x100, 0}, +/* UNIX__NONULL */ {NULL, _ALL_ON_, 0x200, 0}, +/* UNIX__QUIET */ {NULL, _ALL_ON_, 0x400, 0}, +/* UNIX_USE_AUTHTOK */ {"use_authtok", _ALL_ON_, 0x800, 0}, +/* UNIX_SHADOW */ {"shadow", _ALL_ON_, 0x1000, 0}, +/* UNIX_MD5_PASS */ {"md5", _ALL_ON_^(0x2C22000), 0x2000, 1}, +/* UNIX__NULLOK */ {"nullok", _ALL_ON_^(0x200), 0, 0}, +/* UNIX_DEBUG */ {"debug", _ALL_ON_, 0x4000, 0}, +/* UNIX_NODELAY */ {"nodelay", _ALL_ON_, 0x8000, 0}, +/* UNIX_NIS */ {"nis", _ALL_ON_, 0x10000, 0}, +/* UNIX_BIGCRYPT */ {"bigcrypt", _ALL_ON_^(0x2C22000), 0x20000, 1}, +/* UNIX_LIKE_AUTH */ {"likeauth", _ALL_ON_, 0x40000, 0}, +/* UNIX_REMEMBER_PASSWD */ {"remember=", _ALL_ON_, 0x80000, 0}, +/* UNIX_NOREAP */ {"noreap", _ALL_ON_, 0x100000, 0}, +/* UNIX_BROKEN_SHADOW */ {"broken_shadow", _ALL_ON_, 0x200000, 0}, +/* UNIX_SHA256_PASS */ {"sha256", _ALL_ON_^(0x2C22000), 0x400000, 1}, +/* UNIX_SHA512_PASS */ {"sha512", _ALL_ON_^(0x2C22000), 0x800000, 1}, +/* UNIX_ALGO_ROUNDS */ {"rounds=", _ALL_ON_, 0x1000000, 0}, +/* UNIX_BLOWFISH_PASS */ {"blowfish", _ALL_ON_^(0x2C22000),0x2000000, 1}, +/* UNIX_MIN_PASS_LEN */ {"minlen=", _ALL_ON_, 0x4000000, 0}, +/* UNIX_OBSCURE_CHECKS */ {"obscure", _ALL_ON_, 0x8000000, 0}, }; #define UNIX_DEFAULTS (unix_args[UNIX__NONULL].flag) Index: pam.debian/modules/pam_unix/pam_unix.8.xml =================================================================== --- pam.debian.orig/modules/pam_unix/pam_unix.8.xml +++ pam.debian/modules/pam_unix/pam_unix.8.xml @@ -337,8 +337,81 @@ Set a minimum password length of n - characters. The max. for DES crypt based passwords are 8 - characters. + characters. The default value is 6. The maximum for DES + crypt-based passwords is 8 characters. + + + + + + + + + + Enable some extra checks on password strength. These checks + are based on the "obscure" checks in the original shadow + package. The behavior is similar to the pam_cracklib + module, but for non-dictionary-based checks. The following + checks are implemented: + + + + + + + + Verifies that the new password is not a palindrome + of (i.e., the reverse of) the previous one. + + + + + + + + + + Verifies that the new password isn't the same as the + old one with a change of case. + + + + + + + + + + Verifies that the new password isn't too much like + the previous one. + + + + + + + + + + Is the new password too simple? This is based on + the length of the password and the number of + different types of characters (alpha, numeric, etc.) + used. + + + + + + + + + + Is the new password a rotated version of the old + password? (E.g., "billy" and "illyb") + + + + Index: pam.debian/modules/pam_unix/obscure.c =================================================================== --- /dev/null +++ pam.debian/modules/pam_unix/obscure.c @@ -0,0 +1,198 @@ +/* + * Copyright 1989 - 1994, Julianne Frances Haugh + * All rights reserved. + * + * 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. + * + * 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. + */ + +#include "config.h" + +#include +#include +#include +#include +#include +#include +#include +#include + + +#include "support.h" + +/* can't be a palindrome - like `R A D A R' or `M A D A M' */ +static int palindrome(const char *old, const char *new) { + int i, j; + + i = strlen (new); + + for (j = 0;j < i;j++) + if (new[i - j - 1] != new[j]) + return 0; + + return 1; +} + +/* more than half of the characters are different ones. */ +static int similar(const char *old, const char *new) { + int i, j; + + /* + * XXX - sometimes this fails when changing from a simple password + * to a really long one (MD5). For now, I just return success if + * the new password is long enough. Please feel free to suggest + * something better... --marekm + */ + if (strlen(new) >= 8) + return 0; + + for (i = j = 0; new[i] && old[i]; i++) + if (strchr(new, old[i])) + j++; + + if (i >= j * 2) + return 0; + + return 1; +} + +/* a nice mix of characters. */ +static int simple(const char *old, const char *new) { + int digits = 0; + int uppers = 0; + int lowers = 0; + int others = 0; + int size; + int i; + + for (i = 0;new[i];i++) { + if (isdigit (new[i])) + digits++; + else if (isupper (new[i])) + uppers++; + else if (islower (new[i])) + lowers++; + else + others++; + } + + /* + * 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 (digits) size--; + if (uppers) size--; + if (lowers) size--; + if (others) size--; + + if (size <= i) + return 0; + + return 1; +} + +static char *str_lower(char *string) { + char *cp; + + for (cp = string; *cp; cp++) + *cp = tolower(*cp); + return string; +} + +static const char * password_check(const char *old, const char *new, + const struct passwd *pwdp) { + const char *msg = NULL; + char *oldmono, *newmono, *wrapped; + + if (strcmp(new, old) == 0) + return _("Bad: new password must be different than the old one"); + + newmono = str_lower(strdup(new)); + oldmono = str_lower(strdup(old)); + wrapped = (char *)malloc(strlen(oldmono) * 2 + 1); + strcpy (wrapped, oldmono); + strcat (wrapped, oldmono); + + if (palindrome(oldmono, newmono)) { + msg = _("Bad: new password cannot be a palindrome"); + } else if (strcmp(oldmono, newmono) == 0) { + msg = _("Bad: new and old password must differ by more than just case"); + } else if (similar(oldmono, newmono)) { + msg = _("Bad: new and old password are too similar"); + } else if (simple(old, new)) { + msg = _("Bad: new password is too simple"); + } else if (strstr(wrapped, newmono)) { + msg = _("Bad: new password is just a wrapped version of the old one"); + } + + _pam_delete(newmono); + _pam_delete(oldmono); + _pam_delete(wrapped); + + return msg; +} + +const char *obscure_msg(const char *old, const char *new, + const struct passwd *pwdp, unsigned int ctrl) { + int oldlen, newlen; + char *new1, *old1; + const char *msg; + + if (old == NULL) + return NULL; /* no check if old is NULL */ + + oldlen = strlen(old); + newlen = strlen(new); + + /* Remaining checks are optional. */ + if (off(UNIX_OBSCURE_CHECKS,ctrl)) + return NULL; + + if ((msg = password_check(old, new, pwdp)) != NULL) + 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 */ + + if (!UNIX_DES_CRYPT(ctrl)) + return NULL; /* unlimited password length */ + + if (oldlen <= 8 && newlen <= 8) + return NULL; + + new1 = strndup(new,8); + old1 = strndup(old,8); + + msg = password_check(old1, new1, pwdp); + + _pam_delete(new1); + _pam_delete(old1); + + return msg; +} Index: pam.debian/modules/pam_unix/Makefile.am =================================================================== --- pam.debian.orig/modules/pam_unix/Makefile.am +++ pam.debian/modules/pam_unix/Makefile.am @@ -43,7 +43,7 @@ pam_unix_la_SOURCES = bigcrypt.c pam_unix_acct.c \ pam_unix_auth.c pam_unix_passwd.c pam_unix_sess.c support.c \ - passverify.c yppasswd_xdr.c md5_good.c md5_broken.c + passverify.c yppasswd_xdr.c md5_good.c md5_broken.c obscure.c if STATIC_MODULES pam_unix_la_SOURCES += pam_unix_static.c endif Index: pam.debian/modules/pam_unix/pam_unix.8 =================================================================== --- pam.debian.orig/modules/pam_unix/pam_unix.8 +++ pam.debian/modules/pam_unix/pam_unix.8 @@ -183,7 +183,38 @@ .RS 4 Set a minimum password length of \fIn\fR -characters\&. The max\&. for DES crypt based passwords are 8 characters\&. +characters\&. The default value is 6\&. The maximum for DES crypt\-based passwords is 8 characters\&. +.RE +.PP +\fBobscure\fR +.RS 4 +Enable some extra checks on password strength\&. These checks are based on the "obscure" checks in the original shadow package\&. The behavior is similar to the pam_cracklib module, but for non\-dictionary\-based checks\&. The following checks are implemented: +.PP +\fBPalindrome\fR +.RS 4 +Verifies that the new password is not a palindrome of (i\&.e\&., the reverse of) the previous one\&. +.RE +.PP +\fBCase Change Only\fR +.RS 4 +Verifies that the new password isn\*(Aqt the same as the old one with a change of case\&. +.RE +.PP +\fBSimilar\fR +.RS 4 +Verifies that the new password isn\*(Aqt too much like the previous one\&. +.RE +.PP +\fBSimple\fR +.RS 4 +Is the new password too simple? This is based on the length of the password and the number of different types of characters (alpha, numeric, etc\&.) used\&. +.RE +.PP +\fBRotated\fR +.RS 4 +Is the new password a rotated version of the old password? (E\&.g\&., "billy" and "illyb") +.RE +.sp .RE .PP Invalid arguments are logged with diff --git a/modules/pam_unix/README b/modules/pam_unix/README index 26c06e23..a1289409 100644 --- a/modules/pam_unix/README +++ b/modules/pam_unix/README @@ -12,9 +12,9 @@ shadow file as well if shadow is enabled. The account component performs the task of establishing the status of the user's account and password based on the following shadow elements: expire, last_change, max_change, min_change, warn_change. In the case of the latter, it -may offer advice to the user on changing their password or, through the +may offer advice to the user on changing their password or, through the PAM_AUTHTOKEN_REQD return, delay giving service to the user until they have -established a new password. The entries listed above are documented in the +established a new password. The entries listed above are documented in the shadow(5) manual page. Should the user's record not contain one or more of these entries, the corresponding shadow check is not performed. @@ -100,7 +100,7 @@ remember=n The last n passwords for each user are saved in /etc/security/opasswd in order to force password change history and keep the user from alternating - between the same password too frequently. Instead of this option the + between the same password too frequently. Instead of this option the pam_pwhistory module should be used. shadow @@ -146,8 +146,40 @@ broken_shadow minlen=n - Set a minimum password length of n characters. The max. for DES crypt based - passwords are 8 characters. + Set a minimum password length of n characters. The default value is 6. The + maximum for DES crypt-based passwords is 8 characters. + +obscure + + Enable some extra checks on password strength. These checks are based on + the "obscure" checks in the original shadow package. The behavior is + similar to the pam_cracklib module, but for non-dictionary-based checks. + The following checks are implemented: + + Palindrome + + Verifies that the new password is not a palindrome of (i.e., the + reverse of) the previous one. + + Case Change Only + + Verifies that the new password isn't the same as the old one with a + change of case. + + Similar + + Verifies that the new password isn't too much like the previous one. + + Simple + + Is the new password too simple? This is based on the length of the + password and the number of different types of characters (alpha, + numeric, etc.) used. + + Rotated + + Is the new password a rotated version of the old password? (E.g., + "billy" and "illyb") Invalid arguments are logged with syslog(3).