home: add pam_systemd_home.so PAM hookup

In a way fixes: https://bugs.freedesktop.org/show_bug.cgi?id=67474
This commit is contained in:
Lennart Poettering 2019-07-04 19:06:26 +02:00
parent 4aa0a8ac3e
commit 26cf9fb7f8
5 changed files with 1007 additions and 11 deletions

View File

@ -3,17 +3,21 @@
# You really want to adjust this to your local distribution. If you use this
# unmodified you are not building systems safely and securely.
auth sufficient pam_unix.so nullok try_first_pass
auth required pam_deny.so
auth sufficient pam_unix.so
-auth sufficient pam_systemd_home.so
auth required pam_deny.so
account required pam_nologin.so
account sufficient pam_unix.so
account required pam_permit.so
account required pam_nologin.so
-account sufficient pam_systemd_home.so
account sufficient pam_unix.so
account required pam_permit.so
password sufficient pam_unix.so nullok sha512 shadow try_first_pass try_authtok
password required pam_deny.so
-password sufficient pam_systemd_home.so
password sufficient pam_unix.so sha512 shadow try_first_pass try_authtok
password required pam_deny.so
-session optional pam_keyinit.so revoke
-session optional pam_loginuid.so
-session optional pam_systemd.so
session sufficient pam_unix.so
-session optional pam_keyinit.so revoke
-session optional pam_loginuid.so
-session optional pam_systemd_home.so
-session optional pam_systemd.so
session required pam_unix.so

View File

@ -2102,6 +2102,26 @@ if conf.get('ENABLE_HOMED') == 1
install_rpath : rootlibexecdir,
install : true,
install_dir : rootbindir)
if conf.get('HAVE_PAM') == 1
version_script_arg = join_paths(project_source_root, pam_systemd_home_sym)
pam_systemd = shared_library(
'pam_systemd_home',
pam_systemd_home_c,
name_prefix : '',
include_directories : includes,
link_args : ['-shared',
'-Wl,--version-script=' + version_script_arg],
link_with : [libsystemd_static,
libshared_static],
dependencies : [threads,
libpam,
libpam_misc,
libcrypt],
link_depends : pam_systemd_home_sym,
install : true,
install_dir : pamlibdir)
endif
endif
foreach alias : ['halt', 'poweroff', 'reboot', 'runlevel', 'shutdown', 'telinit']

View File

@ -62,6 +62,15 @@ homectl_sources = files('''
user-record-util.h
'''.split())
pam_systemd_home_sym = 'src/home/pam_systemd_home.sym'
pam_systemd_home_c = files('''
home-util.c
home-util.h
pam_systemd_home.c
user-record-util.c
user-record-util.h
'''.split())
if conf.get('ENABLE_HOMED') == 1
install_data('org.freedesktop.home1.conf',
install_dir : dbuspolicydir)

951
src/home/pam_systemd_home.c Normal file
View File

@ -0,0 +1,951 @@
/* SPDX-License-Identifier: LGPL-2.1+ */
#include <security/pam_ext.h>
#include <security/pam_modules.h>
#include "sd-bus.h"
#include "bus-common-errors.h"
#include "errno-util.h"
#include "fd-util.h"
#include "home-util.h"
#include "memory-util.h"
#include "pam-util.h"
#include "parse-util.h"
#include "strv.h"
#include "user-record-util.h"
#include "user-record.h"
#include "user-util.h"
/* Used for the "systemd-user-record-is-homed" PAM data field, to indicate whether we know whether this user
* record is managed by homed or by something else. */
#define USER_RECORD_IS_HOMED INT_TO_PTR(1)
#define USER_RECORD_IS_OTHER INT_TO_PTR(2)
static int parse_argv(
pam_handle_t *handle,
int argc, const char **argv,
bool *please_suspend,
bool *debug) {
int i;
assert(argc >= 0);
assert(argc == 0 || argv);
for (i = 0; i < argc; i++) {
const char *v;
if ((v = startswith(argv[1], "suspend="))) {
int k;
k = parse_boolean(v);
if (k < 0)
pam_syslog(handle, LOG_WARNING, "Failed to parse suspend-please= argument, ignoring: %s", v);
else if (please_suspend)
*please_suspend = k;
} else if ((v = startswith(argv[i], "debug="))) {
int k;
k = parse_boolean(v);
if (k < 0)
pam_syslog(handle, LOG_WARNING, "Failed to parse debug= argument, ignoring: %s", v);
else if (debug)
*debug = k;
} else
pam_syslog(handle, LOG_WARNING, "Unknown parameter '%s', ignoring", argv[i]);
}
return 0;
}
static int acquire_user_record(
pam_handle_t *handle,
UserRecord **ret_record) {
_cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
_cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
_cleanup_(user_record_unrefp) UserRecord *ur = NULL;
_cleanup_(sd_bus_unrefp) sd_bus *bus = NULL;
const char *username = NULL, *json = NULL;
const void *b = NULL;
int r;
assert(handle);
r = pam_get_user(handle, &username, NULL);
if (r != PAM_SUCCESS) {
pam_syslog(handle, LOG_ERR, "Failed to get user name: %s", pam_strerror(handle, r));
return r;
}
if (isempty(username)) {
pam_syslog(handle, LOG_ERR, "User name not set.");
return PAM_SERVICE_ERR;
}
/* Let's bypass all IPC complexity for the two user names we know for sure we don't manage, and for
* user names we don't consider valid. */
if (STR_IN_SET(username, "root", NOBODY_USER_NAME) || !valid_user_group_name(username))
return PAM_USER_UNKNOWN;
/* Let's check if a previous run determined that this user is not managed by homed. If so, let's exit early */
r = pam_get_data(handle, "systemd-user-record-is-homed", &b);
if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA)) {
/* Failure */
pam_syslog(handle, LOG_ERR, "Failed to get PAM user record is homed flag: %s", pam_strerror(handle, r));
return r;
} else if (b == NULL)
/* Nothing cached yet, need to acquire fresh */
json = NULL;
else if (b != USER_RECORD_IS_HOMED)
/* Definitely not a homed record */
return PAM_USER_UNKNOWN;
else {
/* It's a homed record, let's use the cache, so that we can share it between the session and
* the authentication hooks */
r = pam_get_data(handle, "systemd-user-record", (const void**) &json);
if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA)) {
pam_syslog(handle, LOG_ERR, "Failed to get PAM user record data: %s", pam_strerror(handle, r));
return r;
}
}
if (!json) {
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
_cleanup_free_ char *json_copy = NULL;
r = pam_acquire_bus_connection(handle, &bus);
if (r != PAM_SUCCESS)
return r;
r = sd_bus_call_method(
bus,
"org.freedesktop.home1",
"/org/freedesktop/home1",
"org.freedesktop.home1.Manager",
"GetUserRecordByName",
&error,
&reply,
"s",
username);
if (r < 0) {
if (sd_bus_error_has_name(&error, SD_BUS_ERROR_SERVICE_UNKNOWN) ||
sd_bus_error_has_name(&error, SD_BUS_ERROR_NAME_HAS_NO_OWNER)) {
pam_syslog(handle, LOG_DEBUG, "systemd-homed is not available: %s", bus_error_message(&error, r));
goto user_unknown;
}
if (sd_bus_error_has_name(&error, BUS_ERROR_NO_SUCH_HOME)) {
pam_syslog(handle, LOG_DEBUG, "Not a user managed by systemd-homed: %s", bus_error_message(&error, r));
goto user_unknown;
}
pam_syslog(handle, LOG_ERR, "Failed to query user record: %s", bus_error_message(&error, r));
return PAM_SERVICE_ERR;
}
r = sd_bus_message_read(reply, "sbo", &json, NULL, NULL);
if (r < 0)
return pam_bus_log_parse_error(handle, r);
json_copy = strdup(json);
if (!json_copy)
return pam_log_oom(handle);
r = pam_set_data(handle, "systemd-user-record", json_copy, pam_cleanup_free);
if (r != PAM_SUCCESS) {
pam_syslog(handle, LOG_ERR, "Failed to set PAM user record data: %s", pam_strerror(handle, r));
return r;
}
TAKE_PTR(json_copy);
r = pam_set_data(handle, "systemd-user-record-is-homed", USER_RECORD_IS_HOMED, NULL);
if (r != PAM_SUCCESS) {
pam_syslog(handle, LOG_ERR, "Failed to set PAM user record is homed flag: %s", pam_strerror(handle, r));
return r;
}
}
r = json_parse(json, JSON_PARSE_SENSITIVE, &v, NULL, NULL);
if (r < 0) {
pam_syslog(handle, LOG_ERR, "Failed to parse JSON user record: %s", strerror_safe(r));
return PAM_SERVICE_ERR;
}
ur = user_record_new();
if (!ur)
return pam_log_oom(handle);
r = user_record_load(ur, v, USER_RECORD_LOAD_REFUSE_SECRET);
if (r < 0) {
pam_syslog(handle, LOG_ERR, "Failed to load user record: %s", strerror_safe(r));
return PAM_SERVICE_ERR;
}
if (!streq_ptr(username, ur->user_name)) {
pam_syslog(handle, LOG_ERR, "Acquired user record does not match user name.");
return PAM_SERVICE_ERR;
}
if (ret_record)
*ret_record = TAKE_PTR(ur);
return PAM_SUCCESS;
user_unknown:
/* Cache this, so that we don't check again */
r = pam_set_data(handle, "systemd-user-record-is-homed", USER_RECORD_IS_OTHER, NULL);
if (r != PAM_SUCCESS)
pam_syslog(handle, LOG_ERR, "Failed to set PAM user record is homed flag, ignoring: %s", pam_strerror(handle, r));
return PAM_USER_UNKNOWN;
}
static int release_user_record(pam_handle_t *handle) {
int r, k;
r = pam_set_data(handle, "systemd-user-record", NULL, NULL);
if (r != PAM_SUCCESS)
pam_syslog(handle, LOG_ERR, "Failed to release PAM user record data: %s", pam_strerror(handle, r));
k = pam_set_data(handle, "systemd-user-record-is-homed", NULL, NULL);
if (k != PAM_SUCCESS)
pam_syslog(handle, LOG_ERR, "Failed to release PAM user record is homed flag: %s", pam_strerror(handle, k));
return IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA) ? k : r;
}
static void cleanup_home_fd(pam_handle_t *handle, void *data, int error_status) {
safe_close(PTR_TO_FD(data));
}
static int handle_generic_user_record_error(
pam_handle_t *handle,
const char *user_name,
UserRecord *secret,
int ret,
const sd_bus_error *error) {
assert(user_name);
assert(secret);
assert(error);
int r;
/* Logs about all errors, except for PAM_CONV_ERR, i.e. when requesting more info failed. */
if (sd_bus_error_has_name(error, BUS_ERROR_HOME_ABSENT)) {
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, "Home of user %s is currently absent, please plug in the necessary storage device or backing file system.", user_name);
pam_syslog(handle, LOG_ERR, "Failed to acquire home for user %s: %s", user_name, bus_error_message(error, ret));
return PAM_PERM_DENIED;
} else if (sd_bus_error_has_name(error, BUS_ERROR_AUTHENTICATION_LIMIT_HIT)) {
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, "Too frequent unsuccessful login attempts for user %s, try again later.", user_name);
pam_syslog(handle, LOG_ERR, "Failed to acquire home for user %s: %s", user_name, bus_error_message(error, ret));
return PAM_MAXTRIES;
} else if (sd_bus_error_has_name(error, BUS_ERROR_BAD_PASSWORD)) {
_cleanup_(erase_and_freep) char *newp = NULL;
/* This didn't work? Ask for an (additional?) password */
if (strv_isempty(secret->password))
r = pam_prompt(handle, PAM_PROMPT_ECHO_OFF, &newp, "Password: ");
else
r = pam_prompt(handle, PAM_PROMPT_ECHO_OFF, &newp, "Password incorrect or not sufficient for authentication of user %s, please try again: ", user_name);
if (r != PAM_SUCCESS)
return PAM_CONV_ERR; /* no logging here */
if (isempty(newp)) {
pam_syslog(handle, LOG_DEBUG, "Password request aborted.");
return PAM_AUTHTOK_ERR;
}
r = user_record_set_password(secret, STRV_MAKE(newp), true);
if (r < 0) {
pam_syslog(handle, LOG_ERR, "Failed to store password: %s", strerror_safe(r));
return PAM_SERVICE_ERR;
}
} else if (sd_bus_error_has_name(error, BUS_ERROR_BAD_PASSWORD_AND_NO_TOKEN)) {
_cleanup_(erase_and_freep) char *newp = NULL;
if (strv_isempty(secret->password))
r = pam_prompt(handle, PAM_PROMPT_ECHO_OFF, &newp, "Security token of user %s not inserted, please enter password: ", user_name);
else
r = pam_prompt(handle, PAM_PROMPT_ECHO_OFF, &newp, "Password incorrect or not sufficient, and configured security token of user %s not inserted, please enter password: ", user_name);
if (r != PAM_SUCCESS)
return PAM_CONV_ERR; /* no logging here */
if (isempty(newp)) {
pam_syslog(handle, LOG_DEBUG, "Password request aborted.");
return PAM_AUTHTOK_ERR;
}
r = user_record_set_password(secret, STRV_MAKE(newp), true);
if (r < 0) {
pam_syslog(handle, LOG_ERR, "Failed to store password: %s", strerror_safe(r));
return PAM_SERVICE_ERR;
}
} else if (sd_bus_error_has_name(error, BUS_ERROR_TOKEN_PIN_NEEDED)) {
_cleanup_(erase_and_freep) char *newp = NULL;
r = pam_prompt(handle, PAM_PROMPT_ECHO_OFF, &newp, "Please enter security token PIN: ");
if (r != PAM_SUCCESS)
return PAM_CONV_ERR; /* no logging here */
if (isempty(newp)) {
pam_syslog(handle, LOG_DEBUG, "PIN request aborted.");
return PAM_AUTHTOK_ERR;
}
r = user_record_set_pkcs11_pin(secret, STRV_MAKE(newp), false);
if (r < 0) {
pam_syslog(handle, LOG_ERR, "Failed to store PIN: %s", strerror_safe(r));
return PAM_SERVICE_ERR;
}
} else if (sd_bus_error_has_name(error, BUS_ERROR_TOKEN_PROTECTED_AUTHENTICATION_PATH_NEEDED)) {
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, "Please authenticate physically on security token of user %s.", user_name);
r = user_record_set_pkcs11_protected_authentication_path_permitted(secret, true);
if (r < 0) {
pam_syslog(handle, LOG_ERR, "Failed to set PKCS#11 protected authentication path permitted flag: %s", strerror_safe(r));
return PAM_SERVICE_ERR;
}
} else if (sd_bus_error_has_name(error, BUS_ERROR_TOKEN_BAD_PIN)) {
_cleanup_(erase_and_freep) char *newp = NULL;
r = pam_prompt(handle, PAM_PROMPT_ECHO_OFF, &newp, "Security token PIN incorrect, please enter PIN for security token of user %s again: ", user_name);
if (r != PAM_SUCCESS)
return PAM_CONV_ERR; /* no logging here */
if (isempty(newp)) {
pam_syslog(handle, LOG_DEBUG, "PIN request aborted.");
return PAM_AUTHTOK_ERR;
}
r = user_record_set_pkcs11_pin(secret, STRV_MAKE(newp), false);
if (r < 0) {
pam_syslog(handle, LOG_ERR, "Failed to store PIN: %s", strerror_safe(r));
return PAM_SERVICE_ERR;
}
} else if (sd_bus_error_has_name(error, BUS_ERROR_TOKEN_BAD_PIN_FEW_TRIES_LEFT)) {
_cleanup_(erase_and_freep) char *newp = NULL;
r = pam_prompt(handle, PAM_PROMPT_ECHO_OFF, &newp, "Security token PIN incorrect (only a few tries left!), please enter PIN for security token of user %s again: ", user_name);
if (r != PAM_SUCCESS)
return PAM_CONV_ERR; /* no logging here */
if (isempty(newp)) {
pam_syslog(handle, LOG_DEBUG, "PIN request aborted.");
return PAM_AUTHTOK_ERR;
}
r = user_record_set_pkcs11_pin(secret, STRV_MAKE(newp), false);
if (r < 0) {
pam_syslog(handle, LOG_ERR, "Failed to store PIN: %s", strerror_safe(r));
return PAM_SERVICE_ERR;
}
} else if (sd_bus_error_has_name(error, BUS_ERROR_TOKEN_BAD_PIN_ONE_TRY_LEFT)) {
_cleanup_(erase_and_freep) char *newp = NULL;
r = pam_prompt(handle, PAM_PROMPT_ECHO_OFF, &newp, "Security token PIN incorrect (only one try left!), please enter PIN for security token of user %s again: ", user_name);
if (r != PAM_SUCCESS)
return PAM_CONV_ERR; /* no logging here */
if (isempty(newp)) {
pam_syslog(handle, LOG_DEBUG, "PIN request aborted.");
return PAM_AUTHTOK_ERR;
}
r = user_record_set_pkcs11_pin(secret, STRV_MAKE(newp), false);
if (r < 0) {
pam_syslog(handle, LOG_ERR, "Failed to store PIN: %s", strerror_safe(r));
return PAM_SERVICE_ERR;
}
} else {
pam_syslog(handle, LOG_ERR, "Failed to acquire home for user %s: %s", user_name, bus_error_message(error, ret));
return PAM_SERVICE_ERR;
}
return PAM_SUCCESS;
}
static int acquire_home(
pam_handle_t *handle,
bool please_authenticate,
bool please_suspend,
bool debug) {
_cleanup_(user_record_unrefp) UserRecord *ur = NULL, *secret = NULL;
bool do_auth = please_authenticate, home_not_active = false, home_locked = false;
_cleanup_(sd_bus_unrefp) sd_bus *bus = NULL;
_cleanup_close_ int acquired_fd = -1;
const void *home_fd_ptr = NULL;
unsigned n_attempts = 0;
int r;
assert(handle);
/* This acquires a reference to a home directory in one of two ways: if please_authenticate is true,
* then we'll call AcquireHome() after asking the user for a password. Otherwise it tries to call
* RefHome() and if that fails queries the user for a password and uses AcquireHome().
*
* The idea is that the PAM authentication hook sets please_authenticate and thus always
* authenticates, while the other PAM hooks unset it so that they can a ref of their own without
* authentication if possible, but with authentication if necessary. */
/* If we already have acquired the fd, let's shortcut this */
r = pam_get_data(handle, "systemd-home-fd", &home_fd_ptr);
if (r == PAM_SUCCESS && PTR_TO_INT(home_fd_ptr) >= 0)
return PAM_SUCCESS;
r = pam_acquire_bus_connection(handle, &bus);
if (r != PAM_SUCCESS)
return r;
r = acquire_user_record(handle, &ur);
if (r != PAM_SUCCESS)
return r;
/* Implement our own retry loop here instead of relying on the PAM client's one. That's because it
* might happen that the the record we stored on the host does not match the encryption password of
* the LUKS image in case the image was used in a different system where the password was
* changed. In that case it will happen that the LUKS password and the host password are
* different, and we handle that by collecting and passing multiple passwords in that case. Hence we
* treat bad passwords as a request to collect one more password and pass the new all all previously
* used passwords again. */
for (;;) {
_cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL, *reply = NULL;
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
if (do_auth && !secret) {
const char *cached_password = NULL;
secret = user_record_new();
if (!secret)
return pam_log_oom(handle);
/* If there's already a cached password, use it. But if not let's authenticate
* without anything, maybe some other authentication mechanism systemd-homed
* implements (such as PKCS#11) allows us to authenticate without anything else. */
r = pam_get_item(handle, PAM_AUTHTOK, (const void**) &cached_password);
if (!IN_SET(r, PAM_BAD_ITEM, PAM_SUCCESS)) {
pam_syslog(handle, LOG_ERR, "Failed to get cached password: %s", pam_strerror(handle, r));
return r;
}
if (!isempty(cached_password)) {
r = user_record_set_password(secret, STRV_MAKE(cached_password), true);
if (r < 0) {
pam_syslog(handle, LOG_ERR, "Failed to store password: %s", strerror_safe(r));
return PAM_SERVICE_ERR;
}
}
}
r = sd_bus_message_new_method_call(
bus,
&m,
"org.freedesktop.home1",
"/org/freedesktop/home1",
"org.freedesktop.home1.Manager",
do_auth ? "AcquireHome" : "RefHome");
if (r < 0)
return pam_bus_log_create_error(handle, r);
r = sd_bus_message_append(m, "s", ur->user_name);
if (r < 0)
return pam_bus_log_create_error(handle, r);
if (do_auth) {
r = bus_message_append_secret(m, secret);
if (r < 0)
return pam_bus_log_create_error(handle, r);
}
r = sd_bus_message_append(m, "b", please_suspend);
if (r < 0)
return pam_bus_log_create_error(handle, r);
r = sd_bus_call(bus, m, HOME_SLOW_BUS_CALL_TIMEOUT_USEC, &error, &reply);
if (r < 0) {
if (sd_bus_error_has_name(&error, BUS_ERROR_HOME_NOT_ACTIVE))
/* Only on RefHome(): We can't access the home directory currently, unless
* it's unlocked with a password. Hence, let's try this again, this time with
* authentication. */
home_not_active = true;
else if (sd_bus_error_has_name(&error, BUS_ERROR_HOME_LOCKED))
home_locked = true; /* Similar */
else {
r = handle_generic_user_record_error(handle, ur->user_name, secret, r, &error);
if (r == PAM_CONV_ERR) {
/* Password/PIN prompts will fail in certain environments, for example when
* we are called from OpenSSH's account or session hooks, or in systemd's
* per-service PAM logic. In that case, print a friendly message and accept
* failure. */
if (home_not_active)
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, "Home of user %s is currently not active, please log in locally first.", ur->user_name);
if (home_locked)
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, "Home of user %s is currently locked, please unlock locally first.", ur->user_name);
pam_syslog(handle, please_authenticate ? LOG_ERR : LOG_DEBUG, "Failed to prompt for password/prompt.");
return home_not_active || home_locked ? PAM_PERM_DENIED : PAM_CONV_ERR;
}
if (r != PAM_SUCCESS)
return r;
}
} else {
int fd;
r = sd_bus_message_read(reply, "h", &fd);
if (r < 0)
return pam_bus_log_parse_error(handle, r);
acquired_fd = fcntl(fd, F_DUPFD_CLOEXEC, 3);
if (acquired_fd < 0) {
pam_syslog(handle, LOG_ERR, "Failed to duplicate acquired fd: %s", bus_error_message(&error, r));
return PAM_SERVICE_ERR;
}
break;
}
if (++n_attempts >= 5) {
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, "Too many unsuccessful login attempts for user %s, refusing.", ur->user_name);
pam_syslog(handle, LOG_ERR, "Failed to acquire home for user %s: %s", ur->user_name, bus_error_message(&error, r));
return PAM_MAXTRIES;
}
/* Try again, this time with authentication if we didn't do that before. */
do_auth = true;
}
r = pam_set_data(handle, "systemd-home-fd", FD_TO_PTR(acquired_fd), cleanup_home_fd);
if (r < 0) {
pam_syslog(handle, LOG_ERR, "Failed to set PAM bus data: %s", pam_strerror(handle, r));
return r;
}
TAKE_FD(acquired_fd);
if (do_auth) {
/* We likely just activated the home directory, let's flush out the user record, since a
* newer embedded user record might have been acquired from the activation. */
r = release_user_record(handle);
if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA))
return r;
}
pam_syslog(handle, LOG_NOTICE, "Home for user %s successfully acquired.", ur->user_name);
return PAM_SUCCESS;
}
static int release_home_fd(pam_handle_t *handle) {
const void *home_fd_ptr = NULL;
int r;
r = pam_get_data(handle, "systemd-home-fd", &home_fd_ptr);
if (r == PAM_NO_MODULE_DATA || PTR_TO_FD(home_fd_ptr) < 0)
return PAM_NO_MODULE_DATA;
r = pam_set_data(handle, "systemd-home-fd", NULL, NULL);
if (r != PAM_SUCCESS)
pam_syslog(handle, LOG_ERR, "Failed to release PAM home reference fd: %s", pam_strerror(handle, r));
return r;
}
_public_ PAM_EXTERN int pam_sm_authenticate(
pam_handle_t *handle,
int flags,
int argc, const char **argv) {
bool debug = false, suspend_please = false;
if (parse_argv(handle,
argc, argv,
&suspend_please,
&debug) < 0)
return PAM_AUTH_ERR;
if (debug)
pam_syslog(handle, LOG_DEBUG, "pam-systemd-homed authenticating");
return acquire_home(handle, /* please_authenticate= */ true, suspend_please, debug);
}
_public_ PAM_EXTERN int pam_sm_setcred(pam_handle_t *pamh, int flags, int argc, const char **argv) {
return PAM_SUCCESS;
}
_public_ PAM_EXTERN int pam_sm_open_session(
pam_handle_t *handle,
int flags,
int argc, const char **argv) {
bool debug = false, suspend_please = false;
int r;
if (parse_argv(handle,
argc, argv,
&suspend_please,
&debug) < 0)
return PAM_SESSION_ERR;
if (debug)
pam_syslog(handle, LOG_DEBUG, "pam-systemd-homed session start");
r = acquire_home(handle, /* please_authenticate = */ false, suspend_please, debug);
if (r == PAM_USER_UNKNOWN) /* Not managed by us? Don't complain. */
return PAM_SUCCESS;
if (r != PAM_SUCCESS)
return r;
r = pam_putenv(handle, "SYSTEMD_HOME=1");
if (r != PAM_SUCCESS) {
pam_syslog(handle, LOG_ERR, "Failed to set PAM environment variable $SYSTEMD_HOME: %s", pam_strerror(handle, r));
return r;
}
/* Let's release the D-Bus connection, after all the session might live quite a long time, and we are
* not going to process the bus connection in that time, so let's better close before the daemon
* kicks us off because we are not processing anything. */
(void) pam_release_bus_connection(handle);
return PAM_SUCCESS;
}
_public_ PAM_EXTERN int pam_sm_close_session(
pam_handle_t *handle,
int flags,
int argc, const char **argv) {
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
_cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
_cleanup_(sd_bus_unrefp) sd_bus *bus = NULL;
const char *username = NULL;
bool debug = false;
int r;
if (parse_argv(handle,
argc, argv,
NULL,
&debug) < 0)
return PAM_SESSION_ERR;
if (debug)
pam_syslog(handle, LOG_DEBUG, "pam-systemd-homed session end");
/* Let's explicitly drop the reference to the homed session, so that the subsequent ReleaseHome()
* call will be able to do its thing. */
r = release_home_fd(handle);
if (r == PAM_NO_MODULE_DATA) /* Nothing to do, we never acquired an fd */
return PAM_SUCCESS;
if (r != PAM_SUCCESS)
return r;
r = pam_get_user(handle, &username, NULL);
if (r != PAM_SUCCESS) {
pam_syslog(handle, LOG_ERR, "Failed to get user name: %s", pam_strerror(handle, r));
return r;
}
r = pam_acquire_bus_connection(handle, &bus);
if (r != PAM_SUCCESS)
return r;
r = sd_bus_message_new_method_call(
bus,
&m,
"org.freedesktop.home1",
"/org/freedesktop/home1",
"org.freedesktop.home1.Manager",
"ReleaseHome");
if (r < 0)
return pam_bus_log_create_error(handle, r);
r = sd_bus_message_append(m, "s", username);
if (r < 0)
return pam_bus_log_create_error(handle, r);
r = sd_bus_call(bus, m, HOME_SLOW_BUS_CALL_TIMEOUT_USEC, &error, NULL);
if (r < 0) {
if (sd_bus_error_has_name(&error, BUS_ERROR_HOME_BUSY))
pam_syslog(handle, LOG_NOTICE, "Not deactivating home directory of %s, as it is still used.", username);
else {
pam_syslog(handle, LOG_ERR, "Failed to release user home: %s", bus_error_message(&error, r));
return PAM_SESSION_ERR;
}
}
return PAM_SUCCESS;
}
_public_ PAM_EXTERN int pam_sm_acct_mgmt(
pam_handle_t *handle,
int flags,
int argc,
const char **argv) {
_cleanup_(user_record_unrefp) UserRecord *ur = NULL;
bool debug = false, please_suspend = false;
usec_t t;
int r;
if (parse_argv(handle,
argc, argv,
&please_suspend,
&debug) < 0)
return PAM_AUTH_ERR;
if (debug)
pam_syslog(handle, LOG_DEBUG, "pam-systemd-homed account management");
r = acquire_home(handle, /* please_authenticate = */ false, please_suspend, debug);
if (r == PAM_USER_UNKNOWN)
return PAM_SUCCESS; /* we don't have anything to say about users we don't manage */
if (r != PAM_SUCCESS)
return r;
r = acquire_user_record(handle, &ur);
if (r != PAM_SUCCESS)
return r;
r = user_record_test_blocked(ur);
switch (r) {
case -ESTALE:
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, "User record is newer than current system time, prohibiting access.");
return PAM_ACCT_EXPIRED;
case -ENOLCK:
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, "User record is blocked, prohibiting access.");
return PAM_ACCT_EXPIRED;
case -EL2HLT:
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, "User record is not valid yet, prohibiting access.");
return PAM_ACCT_EXPIRED;
case -EL3HLT:
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, "User record is not valid anymore, prohibiting access.");
return PAM_ACCT_EXPIRED;
default:
if (r < 0) {
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, "User record not valid, prohibiting access.");
return PAM_ACCT_EXPIRED;
}
break;
}
t = user_record_ratelimit_next_try(ur);
if (t != USEC_INFINITY) {
usec_t n = now(CLOCK_REALTIME);
if (t > n) {
char buf[FORMAT_TIMESPAN_MAX];
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, "Too many logins, try again in %s.",
format_timespan(buf, sizeof(buf), t - n, USEC_PER_SEC));
return PAM_MAXTRIES;
}
}
r = user_record_test_password_change_required(ur);
switch (r) {
case -EKEYREVOKED:
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, "Password change required.");
return PAM_NEW_AUTHTOK_REQD;
case -EOWNERDEAD:
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, "Password expired, change requird.");
return PAM_NEW_AUTHTOK_REQD;
case -EKEYREJECTED:
/* Strictly speaking this is only about password expiration, and we might want to allow
* authentication via PKCS#11 or so, but let's ignore this fine distinction for now. */
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, "Password is expired, but can't change, refusing login.");
return PAM_AUTHTOK_EXPIRED;
case -EKEYEXPIRED:
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, "Password will expire soon, please change.");
break;
case -EROFS:
/* All good, just means the password if we wanted to change we couldn't, but we don't need to */
break;
default:
if (r < 0) {
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, "User record not valid, prohibiting access.");
return PAM_AUTHTOK_EXPIRED;
}
break;
}
return PAM_SUCCESS;
}
_public_ PAM_EXTERN int pam_sm_chauthtok(
pam_handle_t *handle,
int flags,
int argc,
const char **argv) {
_cleanup_(user_record_unrefp) UserRecord *ur = NULL, *old_secret = NULL, *new_secret = NULL;
const char *old_password = NULL, *new_password = NULL;
_cleanup_(sd_bus_unrefp) sd_bus *bus = NULL;
unsigned n_attempts = 0;
bool debug = false;
int r;
if (parse_argv(handle,
argc, argv,
NULL,
&debug) < 0)
return PAM_AUTH_ERR;
if (debug)
pam_syslog(handle, LOG_DEBUG, "pam-systemd-homed account management");
r = pam_acquire_bus_connection(handle, &bus);
if (r != PAM_SUCCESS)
return r;
r = acquire_user_record(handle, &ur);
if (r != PAM_SUCCESS)
return r;
/* Start with cached credentials */
r = pam_get_item(handle, PAM_OLDAUTHTOK, (const void**) &old_password);
if (!IN_SET(r, PAM_BAD_ITEM, PAM_SUCCESS)) {
pam_syslog(handle, LOG_ERR, "Failed to get old password: %s", pam_strerror(handle, r));
return r;
}
r = pam_get_item(handle, PAM_AUTHTOK, (const void**) &new_password);
if (!IN_SET(r, PAM_BAD_ITEM, PAM_SUCCESS)) {
pam_syslog(handle, LOG_ERR, "Failed to get cached password: %s", pam_strerror(handle, r));
return r;
}
if (isempty(new_password)) {
/* No, it's not cached, then let's ask for the password and its verification, and cache
* it. */
r = pam_get_authtok_noverify(handle, &new_password, "New password: ");
if (r != PAM_SUCCESS) {
pam_syslog(handle, LOG_ERR, "Failed to get new password: %s", pam_strerror(handle, r));
return r;
}
if (isempty(new_password)) {
pam_syslog(handle, LOG_DEBUG, "Password request aborted.");
return PAM_AUTHTOK_ERR;
}
r = pam_get_authtok_verify(handle, &new_password, "new password: "); /* Lower case, since PAM prefixes 'Repeat' */
if (r != PAM_SUCCESS) {
pam_syslog(handle, LOG_ERR, "Failed to get password again: %s", pam_strerror(handle, r));
return r;
}
// FIXME: pam_pwquality will ask for the password a third time. It really shouldn't do
// that, and instead assume the password was already verified once when it is found to be
// cached already. needs to be fixed in pam_pwquality
}
/* Now everything is cached and checked, let's exit from the preliminary check */
if (FLAGS_SET(flags, PAM_PRELIM_CHECK))
return PAM_SUCCESS;
old_secret = user_record_new();
if (!old_secret)
return pam_log_oom(handle);
if (!isempty(old_password)) {
r = user_record_set_password(old_secret, STRV_MAKE(old_password), true);
if (r < 0) {
pam_syslog(handle, LOG_ERR, "Failed to store old password: %s", strerror_safe(r));
return PAM_SERVICE_ERR;
}
}
new_secret = user_record_new();
if (!new_secret)
return pam_log_oom(handle);
r = user_record_set_password(new_secret, STRV_MAKE(new_password), true);
if (r < 0) {
pam_syslog(handle, LOG_ERR, "Failed to store new password: %s", strerror_safe(r));
return PAM_SERVICE_ERR;
}
for (;;) {
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
_cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
r = sd_bus_message_new_method_call(
bus,
&m,
"org.freedesktop.home1",
"/org/freedesktop/home1",
"org.freedesktop.home1.Manager",
"ChangePasswordHome");
if (r < 0)
return pam_bus_log_create_error(handle, r);
r = sd_bus_message_append(m, "s", ur->user_name);
if (r < 0)
return pam_bus_log_create_error(handle, r);
r = bus_message_append_secret(m, new_secret);
if (r < 0)
return pam_bus_log_create_error(handle, r);
r = bus_message_append_secret(m, old_secret);
if (r < 0)
return pam_bus_log_create_error(handle, r);
r = sd_bus_call(bus, m, HOME_SLOW_BUS_CALL_TIMEOUT_USEC, &error, NULL);
if (r < 0) {
r = handle_generic_user_record_error(handle, ur->user_name, old_secret, r, &error);
if (r == PAM_CONV_ERR) {
pam_syslog(handle, LOG_ERR, "Failed to prompt for password/prompt.");
return PAM_CONV_ERR;
}
if (r != PAM_SUCCESS)
return r;
} else {
pam_syslog(handle, LOG_NOTICE, "Successfully changed password for user %s.", ur->user_name);
return PAM_SUCCESS;
}
if (++n_attempts >= 5)
break;
/* Try again */
};
pam_syslog(handle, LOG_NOTICE, "Failed to change password for user %s: %m", ur->user_name);
return PAM_MAXTRIES;
}

View File

@ -0,0 +1,12 @@
/* SPDX-License-Identifier: LGPL-2.1+ */
{
global:
pam_sm_authenticate;
pam_sm_setcred;
pam_sm_open_session;
pam_sm_close_session;
pam_sm_acct_mgmt;
pam_sm_chauthtok;
local: *;
};