/*
* Copyright (c) 2000-2002 by Solar Designer. See LICENSE.
*/
#define _XOPEN_SOURCE 600
#define _XOPEN_SOURCE_EXTENDED
#define _XOPEN_VERSION 600
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <limits.h>
#include <unistd.h>
#include <pwd.h>
#ifdef HAVE_SHADOW
#include <shadow.h>
#endif
#define PAM_SM_PASSWORD
#ifndef LINUX_PAM
#include <security/pam_appl.h>
#endif
#include <security/pam_modules.h>
#include "pam_macros.h"
#if !defined(PAM_EXTERN) && !defined(PAM_STATIC)
#define PAM_EXTERN extern
#endif
#if !defined(PAM_AUTHTOK_RECOVERY_ERR) && defined(PAM_AUTHTOK_RECOVER_ERR)
#define PAM_AUTHTOK_RECOVERY_ERR PAM_AUTHTOK_RECOVER_ERR
#endif
#if defined(__sun__) && !defined(LINUX_PAM) && !defined(_OPENPAM)
/* Sun's PAM doesn't use const here */
#define lo_const
#else
#define lo_const const
#endif
typedef lo_const void *pam_item_t;
#include "passwdqc.h"
#define F_ENFORCE_MASK 0x00000003
#define F_ENFORCE_USERS 0x00000001
#define F_ENFORCE_ROOT 0x00000002
#define F_ENFORCE_EVERYONE F_ENFORCE_MASK
#define F_NON_UNIX 0x00000004
#define F_ASK_OLDAUTHTOK_MASK 0x00000030
#define F_ASK_OLDAUTHTOK_PRELIM 0x00000010
#define F_ASK_OLDAUTHTOK_UPDATE 0x00000020
#define F_CHECK_OLDAUTHTOK 0x00000040
#define F_USE_FIRST_PASS 0x00000100
#define F_USE_AUTHTOK 0x00000200
typedef struct {
passwdqc_params_t qc;
int flags;
int retry;
} params_t;
static params_t defaults = {
{
{INT_MAX, 24, 12, 8, 7}, /* min */
40, /* max */
3, /* passphrase_words */
4, /* match_length */
1, /* similar_deny */
42 /* random_bits */
},
F_ENFORCE_EVERYONE, /* flags */
3 /* retry */
};
#define PROMPT_OLDPASS \
"Enter current password: "
#define PROMPT_NEWPASS1 \
"Enter new password: "
#define PROMPT_NEWPASS2 \
"Re-type new password: "
#define MESSAGE_MISCONFIGURED \
"System configuration error. Please contact your administrator."
#define MESSAGE_INVALID_OPTION \
"pam_passwdqc: Invalid option: \"%s\"."
#define MESSAGE_INTRO_PASSWORD \
"\nYou can now choose the new password.\n"
#define MESSAGE_INTRO_BOTH \
"\nYou can now choose the new password or passphrase.\n"
#define MESSAGE_EXPLAIN_PASSWORD_1 \
"A valid password should be a mix of upper and lower case letters,\n" \
"digits and other characters. You can use a%s %d character long\n" \
"password with characters from at least 3 of these 4 classes.\n" \
"Characters that form a common pattern are discarded by the check.\n"
#define MESSAGE_EXPLAIN_PASSWORD_2 \
"A valid password should be a mix of upper and lower case letters,\n" \
"digits and other characters. You can use a%s %d character long\n" \
"password with characters from at least 3 of these 4 classes, or\n" \
"a%s %d character long password containing characters from all the\n" \
"classes. Characters that form a common pattern are discarded by\n" \
"the check.\n"
#define MESSAGE_EXPLAIN_PASSPHRASE \
"A passphrase should be of at least %d words, %d to %d characters\n" \
"long and contain enough different characters.\n"
#define MESSAGE_RANDOM \
"Alternatively, if noone else can see your terminal now, you can\n" \
"pick this as your password: \"%s\".\n"
#define MESSAGE_RANDOMONLY \
"This system is configured to permit randomly generated passwords\n" \
"only. If noone else can see your terminal now, you can pick this\n" \
"as your password: \"%s\". Otherwise, come back later.\n"
#define MESSAGE_RANDOMFAILED \
"This system is configured to use randomly generated passwords\n" \
"only, but the attempt to generate a password has failed. This\n" \
"could happen for a number of reasons: you could have requested\n" \
"an impossible password length, or the access to kernel random\n" \
"number pool could have failed."
#define MESSAGE_TOOLONG \
"This password may be too long for some services. Choose another."
#define MESSAGE_TRUNCATED \
"Warning: your longer password will be truncated to 8 characters."
#define MESSAGE_WEAKPASS \
"Weak password: %s."
#define MESSAGE_NOTRANDOM \
"Sorry, you've mistyped the password that was generated for you."
#define MESSAGE_MISTYPED \
"Sorry, passwords do not match."
#define MESSAGE_RETRY \
"Try again."
static int converse(pam_handle_t *pamh, int style, lo_const char *text,
struct pam_response **resp)
{
pam_item_t item;
lo_const struct pam_conv *conv;
struct pam_message msg, *pmsg;
int status;
status = pam_get_item(pamh, PAM_CONV, &item);
if (status != PAM_SUCCESS)
return status;
conv = item;
pmsg = &msg;
msg.msg_style = style;
msg.msg = (char *)text;
*resp = NULL;
return conv->conv(1, (lo_const struct pam_message **)&pmsg, resp,
conv->appdata_ptr);
}
#ifdef __GNUC__
__attribute__ ((format (printf, 3, 4)))
#endif
static int say(pam_handle_t *pamh, int style, const char *format, ...)
{
va_list args;
char buffer[0x800];
int needed;
struct pam_response *resp;
int status;
va_start(args, format);
needed = vsnprintf(buffer, sizeof(buffer), format, args);
va_end(args);
if ((unsigned int)needed < sizeof(buffer)) {
status = converse(pamh, style, buffer, &resp);
_pam_overwrite(buffer);
} else {
status = PAM_ABORT;
memset(buffer, 0, sizeof(buffer));
}
return status;
}
static int check_max(params_t *params, pam_handle_t *pamh, const char *newpass)
{
if ((int)strlen(newpass) > params->qc.max) {
if (params->qc.max != 8) {
say(pamh, PAM_ERROR_MSG, MESSAGE_TOOLONG);
return -1;
}
say(pamh, PAM_TEXT_INFO, MESSAGE_TRUNCATED);
}
return 0;
}
static int parse(params_t *params, pam_handle_t *pamh,
int argc, const char **argv)
{
const char *p;
char *e;
int i;
unsigned long v;
while (argc) {
if (!strncmp(*argv, "min=", 4)) {
p = *argv + 4;
for (i = 0; i < 5; i++) {
if (!strncmp(p, "disabled", 8)) {
v = INT_MAX;
p += 8;
} else {
v = strtoul(p, &e, 10);
p = e;
}
if (i < 4 && *p++ != ',') break;
if (v > INT_MAX) break;
if (i && (int)v > params->qc.min[i - 1]) break;
params->qc.min[i] = v;
}
if (*p) break;
} else
if (!strncmp(*argv, "max=", 4)) {
v = strtoul(*argv + 4, &e, 10);
if (*e || v < 8 || v > INT_MAX) break;
params->qc.max = v;
} else
if (!strncmp(*argv, "passphrase=", 11)) {
v = strtoul(*argv + 11, &e, 10);
if (*e || v > INT_MAX) break;
params->qc.passphrase_words = v;
} else
if (!strncmp(*argv, "match=", 6)) {
v = strtoul(*argv + 6, &e, 10);
if (*e || v > INT_MAX) break;
params->qc.match_length = v;
} else
if (!strncmp(*argv, "similar=", 8)) {
if (!strcmp(*argv + 8, "permit"))
params->qc.similar_deny = 0;
else
if (!strcmp(*argv + 8, "deny"))
params->qc.similar_deny = 1;
else
break;
} else
if (!strncmp(*argv, "random=", 7)) {
v = strtoul(*argv + 7, &e, 10);
if (!strcmp(e, ",only")) {
e += 5;
params->qc.min[4] = INT_MAX;
}
if (*e || v > INT_MAX) break;
params->qc.random_bits = v;
} else
if (!strncmp(*argv, "enforce=", 8)) {
params->flags &= ~F_ENFORCE_MASK;
if (!strcmp(*argv + 8, "users"))
params->flags |= F_ENFORCE_USERS;
else
if (!strcmp(*argv + 8, "everyone"))
params->flags |= F_ENFORCE_EVERYONE;
else
if (strcmp(*argv + 8, "none"))
break;
} else
if (!strcmp(*argv, "non-unix")) {
if (params->flags & F_CHECK_OLDAUTHTOK) break;
params->flags |= F_NON_UNIX;
} else
if (!strncmp(*argv, "retry=", 6)) {
v = strtoul(*argv + 6, &e, 10);
if (*e || v > INT_MAX) break;
params->retry = v;
} else
if (!strncmp(*argv, "ask_oldauthtok", 14)) {
params->flags &= ~F_ASK_OLDAUTHTOK_MASK;
if (params->flags & F_USE_FIRST_PASS) break;
if (!strcmp(*argv + 14, "=update"))
params->flags |= F_ASK_OLDAUTHTOK_UPDATE;
else
if (!(*argv)[14])
params->flags |= F_ASK_OLDAUTHTOK_PRELIM;
else
break;
} else
if (!strcmp(*argv, "check_oldauthtok")) {
if (params->flags & F_NON_UNIX) break;
params->flags |= F_CHECK_OLDAUTHTOK;
} else
if (!strcmp(*argv, "use_first_pass")) {
if (params->flags & F_ASK_OLDAUTHTOK_MASK) break;
params->flags |= F_USE_FIRST_PASS | F_USE_AUTHTOK;
} else
if (!strcmp(*argv, "use_authtok")) {
params->flags |= F_USE_AUTHTOK;
} else
break;
argc--; argv++;
}
if (argc) {
if (getuid() != 0) {
say(pamh, PAM_ERROR_MSG, MESSAGE_MISCONFIGURED);
} else {
say(pamh, PAM_ERROR_MSG, MESSAGE_INVALID_OPTION, *argv);
}
return PAM_ABORT;
}
return PAM_SUCCESS;
}
PAM_EXTERN int pam_sm_chauthtok(pam_handle_t *pamh, int flags,
int argc, const char **argv)
{
params_t params;
struct pam_response *resp;
struct passwd *pw, fake_pw;
#ifdef HAVE_SHADOW
struct spwd *spw;
#endif
pam_item_t item;
lo_const char *user, *oldpass, *curpass;
char *newpass, *randompass;
const char *reason;
int ask_oldauthtok;
int randomonly, enforce, retries_left, retry_wanted;
int status;
params = defaults;
status = parse(¶ms, pamh, argc, argv);
if (status != PAM_SUCCESS)
return status;
ask_oldauthtok = 0;
if (flags & PAM_PRELIM_CHECK) {
if (params.flags & F_ASK_OLDAUTHTOK_PRELIM)
ask_oldauthtok = 1;
} else
if (flags & PAM_UPDATE_AUTHTOK) {
if (params.flags & F_ASK_OLDAUTHTOK_UPDATE)
ask_oldauthtok = 1;
} else
return PAM_SERVICE_ERR;
if (ask_oldauthtok && getuid() != 0) {
status = converse(pamh, PAM_PROMPT_ECHO_OFF,
PROMPT_OLDPASS, &resp);
if (status == PAM_SUCCESS) {
if (resp && resp->resp) {
status = pam_set_item(pamh,
PAM_OLDAUTHTOK, resp->resp);
_pam_drop_reply(resp, 1);
} else
status = PAM_AUTHTOK_RECOVERY_ERR;
}
if (status != PAM_SUCCESS)
return status;
}
if (flags & PAM_PRELIM_CHECK)
return status;
status = pam_get_item(pamh, PAM_USER, &item);
if (status != PAM_SUCCESS)
return status;
user = item;
status = pam_get_item(pamh, PAM_OLDAUTHTOK, &item);
if (status != PAM_SUCCESS)
return status;
oldpass = item;
if (params.flags & F_NON_UNIX) {
pw = &fake_pw;
pw->pw_name = (char *)user;
pw->pw_gecos = "";
} else {
pw = getpwnam(user);
endpwent();
if (!pw)
return PAM_USER_UNKNOWN;
if ((params.flags & F_CHECK_OLDAUTHTOK) && getuid() != 0) {
if (!oldpass)
status = PAM_AUTH_ERR;
else
#ifdef HAVE_SHADOW
if (!strcmp(pw->pw_passwd, "x")) {
spw = getspnam(user);
endspent();
if (spw) {
if (strcmp(crypt(oldpass, spw->sp_pwdp),
spw->sp_pwdp))
status = PAM_AUTH_ERR;
memset(spw->sp_pwdp, 0,
strlen(spw->sp_pwdp));
} else
status = PAM_AUTH_ERR;
} else
#endif
if (strcmp(crypt(oldpass, pw->pw_passwd),
pw->pw_passwd))
status = PAM_AUTH_ERR;
}
memset(pw->pw_passwd, 0, strlen(pw->pw_passwd));
if (status != PAM_SUCCESS)
return status;
}
randomonly = params.qc.min[4] > params.qc.max;
if (getuid() != 0)
enforce = params.flags & F_ENFORCE_USERS;
else
enforce = params.flags & F_ENFORCE_ROOT;
if (params.flags & F_USE_AUTHTOK) {
status = pam_get_item(pamh, PAM_AUTHTOK, &item);
if (status != PAM_SUCCESS)
return status;
curpass = item;
if (!curpass || (check_max(¶ms, pamh, curpass) && enforce))
return PAM_AUTHTOK_ERR;
reason = _passwdqc_check(¶ms.qc, curpass, oldpass, pw);
if (reason) {
say(pamh, PAM_ERROR_MSG, MESSAGE_WEAKPASS, reason);
if (enforce)
status = PAM_AUTHTOK_ERR;
}
return status;
}
retries_left = params.retry;
retry:
retry_wanted = 0;
if (!randomonly &&
params.qc.passphrase_words && params.qc.min[2] <= params.qc.max)
status = say(pamh, PAM_TEXT_INFO, MESSAGE_INTRO_BOTH);
else
status = say(pamh, PAM_TEXT_INFO, MESSAGE_INTRO_PASSWORD);
if (status != PAM_SUCCESS)
return status;
if (!randomonly && params.qc.min[3] <= params.qc.min[4])
status = say(pamh, PAM_TEXT_INFO, MESSAGE_EXPLAIN_PASSWORD_1,
params.qc.min[3] == 8 || params.qc.min[3] == 11 ? "n" : "",
params.qc.min[3]);
else
if (!randomonly)
status = say(pamh, PAM_TEXT_INFO, MESSAGE_EXPLAIN_PASSWORD_2,
params.qc.min[3] == 8 || params.qc.min[3] == 11 ? "n" : "",
params.qc.min[3],
params.qc.min[4] == 8 || params.qc.min[4] == 11 ? "n" : "",
params.qc.min[4]);
if (status != PAM_SUCCESS)
return status;
if (!randomonly &&
params.qc.passphrase_words &&
params.qc.min[2] <= params.qc.max) {
status = say(pamh, PAM_TEXT_INFO, MESSAGE_EXPLAIN_PASSPHRASE,
params.qc.passphrase_words,
params.qc.min[2], params.qc.max);
if (status != PAM_SUCCESS)
return status;
}
randompass = _passwdqc_random(¶ms.qc);
if (randompass) {
status = say(pamh, PAM_TEXT_INFO, randomonly ?
MESSAGE_RANDOMONLY : MESSAGE_RANDOM, randompass);
if (status != PAM_SUCCESS) {
_pam_overwrite(randompass);
randompass = NULL;
}
} else
if (randomonly) {
say(pamh, PAM_ERROR_MSG, getuid() != 0 ?
MESSAGE_MISCONFIGURED : MESSAGE_RANDOMFAILED);
return PAM_AUTHTOK_ERR;
}
status = converse(pamh, PAM_PROMPT_ECHO_OFF, PROMPT_NEWPASS1, &resp);
if (status == PAM_SUCCESS && (!resp || !resp->resp))
status = PAM_AUTHTOK_ERR;
if (status != PAM_SUCCESS) {
if (randompass) _pam_overwrite(randompass);
return status;
}
newpass = strdup(resp->resp);
_pam_drop_reply(resp, 1);
if (!newpass) {
if (randompass) _pam_overwrite(randompass);
return status;
}
if (check_max(¶ms, pamh, newpass) && enforce) {
status = PAM_AUTHTOK_ERR;
retry_wanted = 1;
}
reason = NULL;
if (status == PAM_SUCCESS &&
(!randompass || !strstr(newpass, randompass)) &&
(randomonly ||
(reason = _passwdqc_check(¶ms.qc, newpass, oldpass, pw)))) {
if (randomonly)
say(pamh, PAM_ERROR_MSG, MESSAGE_NOTRANDOM);
else
say(pamh, PAM_ERROR_MSG, MESSAGE_WEAKPASS, reason);
if (enforce) {
status = PAM_AUTHTOK_ERR;
retry_wanted = 1;
}
}
if (status == PAM_SUCCESS)
status = converse(pamh, PAM_PROMPT_ECHO_OFF,
PROMPT_NEWPASS2, &resp);
if (status == PAM_SUCCESS) {
if (resp && resp->resp) {
if (strcmp(newpass, resp->resp)) {
status = say(pamh,
PAM_ERROR_MSG, MESSAGE_MISTYPED);
if (status == PAM_SUCCESS) {
status = PAM_AUTHTOK_ERR;
retry_wanted = 1;
}
}
_pam_drop_reply(resp, 1);
} else
status = PAM_AUTHTOK_ERR;
}
if (status == PAM_SUCCESS)
status = pam_set_item(pamh, PAM_AUTHTOK, newpass);
if (randompass) _pam_overwrite(randompass);
_pam_overwrite(newpass);
free(newpass);
if (retry_wanted && --retries_left > 0) {
status = say(pamh, PAM_TEXT_INFO, MESSAGE_RETRY);
if (status == PAM_SUCCESS)
goto retry;
}
return status;
}
#ifdef PAM_MODULE_ENTRY
PAM_MODULE_ENTRY("pam_passwdqc");
#elif defined(PAM_STATIC)
struct pam_module _pam_passwdqc_modstruct = {
"pam_passwdqc",
NULL,
NULL,
NULL,
NULL,
NULL,
pam_sm_chauthtok
};
#endif