blob: 27b292f4606dc0e8bda2ae22900ef2ceaaaa378a [file] [log] [blame]
/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include <security/pam_ext.h>
#include <security/pam_modules.h>
#include "sd-bus.h"
#include "bus-common-errors.h"
#include "bus-locator.h"
#include "bus-util.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"
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[i], "suspend="))) {
int k;
k = parse_boolean(v);
if (k < 0)
pam_syslog(handle, LOG_WARNING, "Failed to parse suspend= argument, ignoring: %s", v);
else if (please_suspend)
*please_suspend = k;
} else if (streq(argv[i], "debug")) {
if (debug)
*debug = true;
} 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 parse_env(
pam_handle_t *handle,
bool *please_suspend) {
const char *v;
int r;
/* Let's read the suspend setting from an env var in addition to the PAM command line. That makes it
* easy to declare the features of a display manager in code rather than configuration, and this is
* really a feature of code */
v = pam_getenv(handle, "SYSTEMD_HOME_SUSPEND");
if (!v) {
/* Also check the process env block, so that people can control this via an env var from the
* outside of our process. */
v = secure_getenv("SYSTEMD_HOME_SUSPEND");
if (!v)
return 0;
}
r = parse_boolean(v);
if (r < 0)
pam_syslog(handle, LOG_WARNING, "Failed to parse $SYSTEMD_HOME_SUSPEND argument, ignoring: %s", v);
else if (please_suspend)
*please_suspend = r;
return 0;
}
static int acquire_user_record(
pam_handle_t *handle,
const char *username,
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;
_cleanup_free_ char *homed_field = NULL;
const char *json = NULL;
int r;
assert(handle);
if (!username) {
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, 0))
return PAM_USER_UNKNOWN;
/* We cache the user record in the PAM context. We use a field name that includes the username, since
* clients might change the user name associated with a PAM context underneath us. Notably, 'sudo'
* creates a single PAM context and first authenticates it with the user set to the originating user,
* then updates the user for the destination user and issues the session stack with the same PAM
* context. We thus must be prepared that the user record changes between calls and we keep any
* caching separate. */
homed_field = strjoin("systemd-home-user-record-", username);
if (!homed_field)
return pam_log_oom(handle);
/* Let's use the cache, so that we can share it between the session and the authentication hooks */
r = pam_get_data(handle, homed_field, (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 (r == PAM_SUCCESS && json) {
/* We determined earlier that this is not a homed user? Then exit early. (We use -1 as
* negative cache indicator) */
if (json == POINTER_MAX)
return PAM_USER_UNKNOWN;
} else {
_cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
_cleanup_free_ char *generic_field = NULL, *json_copy = NULL;
r = pam_acquire_bus_connection(handle, &bus);
if (r != PAM_SUCCESS)
return r;
r = bus_call_method(bus, bus_home_mgr, "GetUserRecordByName", &error, &reply, "s", username);
if (r < 0) {
if (bus_error_is_unknown_service(&error)) {
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);
/* First copy: for the homed-specific data field, i.e. where we know the user record is from
* homed */
json_copy = strdup(json);
if (!json_copy)
return pam_log_oom(handle);
r = pam_set_data(handle, homed_field, json_copy, pam_cleanup_free);
if (r != PAM_SUCCESS) {
pam_syslog(handle, LOG_ERR, "Failed to set PAM user record data '%s': %s",
homed_field, pam_strerror(handle, r));
return r;
}
/* Take a second copy: for the generic data field, the one which we share with
* pam_systemd. While we insist on only reusing homed records, pam_systemd is fine with homed
* and non-homed user records. */
json_copy = strdup(json);
if (!json_copy)
return pam_log_oom(handle);
generic_field = strjoin("systemd-user-record-", username);
if (!generic_field)
return pam_log_oom(handle);
r = pam_set_data(handle, generic_field, json_copy, pam_cleanup_free);
if (r != PAM_SUCCESS) {
pam_syslog(handle, LOG_ERR, "Failed to set PAM user record data '%s': %s",
homed_field, pam_strerror(handle, r));
return r;
}
TAKE_PTR(json_copy);
}
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|USER_RECORD_PERMISSIVE);
if (r < 0) {
pam_syslog(handle, LOG_ERR, "Failed to load user record: %s", strerror_safe(r));
return PAM_SERVICE_ERR;
}
/* Safety check if cached record actually matches what we are looking for */
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, homed_field, POINTER_MAX, NULL);
if (r != PAM_SUCCESS)
pam_syslog(handle, LOG_ERR, "Failed to set PAM user record data '%s' to invalid, ignoring: %s",
homed_field, pam_strerror(handle, r));
return PAM_USER_UNKNOWN;
}
static int release_user_record(pam_handle_t *handle, const char *username) {
_cleanup_free_ char *homed_field = NULL, *generic_field = NULL;
int r, k;
assert(handle);
assert(username);
homed_field = strjoin("systemd-home-user-record-", username);
if (!homed_field)
return pam_log_oom(handle);
r = pam_set_data(handle, homed_field, NULL, NULL);
if (r != PAM_SUCCESS)
pam_syslog(handle, LOG_ERR, "Failed to release PAM user record data '%s': %s", homed_field, pam_strerror(handle, r));
generic_field = strjoin("systemd-user-record-", username);
if (!generic_field)
return pam_log_oom(handle);
k = pam_set_data(handle, generic_field, NULL, NULL);
if (k != PAM_SUCCESS)
pam_syslog(handle, LOG_ERR, "Failed to release PAM user record data '%s': %s", generic_field, 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(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;
assert(secret);
/* 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 {
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, "Password incorrect or not sufficient for authentication of user %s.", user_name);
r = pam_prompt(handle, PAM_PROMPT_ECHO_OFF, &newp, "Sorry, try again: ");
}
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;
assert(secret);
if (strv_isempty(secret->password)) {
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, "Security token of user %s not inserted.", user_name);
r = pam_prompt(handle, PAM_PROMPT_ECHO_OFF, &newp, "Try again with password: ");
} else {
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, "Password incorrect or not sufficient, and configured security token of user %s not inserted.", user_name);
r = pam_prompt(handle, PAM_PROMPT_ECHO_OFF, &newp, "Try again with password: ");
}
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;
assert(secret);
r = pam_prompt(handle, PAM_PROMPT_ECHO_OFF, &newp, "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_token_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)) {
assert(secret);
(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_USER_PRESENCE_NEEDED)) {
assert(secret);
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, "Please confirm presence on security token of user %s.", user_name);
r = user_record_set_fido2_user_presence_permitted(secret, true);
if (r < 0) {
pam_syslog(handle, LOG_ERR, "Failed to set FIDO2 user presence permitted flag: %s", strerror_safe(r));
return PAM_SERVICE_ERR;
}
} else if (sd_bus_error_has_name(error, BUS_ERROR_TOKEN_USER_VERIFICATION_NEEDED)) {
assert(secret);
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, "Please verify user on security token of user %s.", user_name);
r = user_record_set_fido2_user_verification_permitted(secret, true);
if (r < 0) {
pam_syslog(handle, LOG_ERR, "Failed to set FIDO2 user verification permitted flag: %s", strerror_safe(r));
return PAM_SERVICE_ERR;
}
} else if (sd_bus_error_has_name(error, BUS_ERROR_TOKEN_PIN_LOCKED)) {
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, "Security token PIN is locked, please unlock it first. (Hint: Removal and re-insertion might suffice.)");
return PAM_SERVICE_ERR;
} else if (sd_bus_error_has_name(error, BUS_ERROR_TOKEN_BAD_PIN)) {
_cleanup_(erase_and_freep) char *newp = NULL;
assert(secret);
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, "Security token PIN incorrect for user %s.", user_name);
r = pam_prompt(handle, PAM_PROMPT_ECHO_OFF, &newp, "Sorry, retry 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_token_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;
assert(secret);
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, "Security token PIN of user %s incorrect (only a few tries left!)", user_name);
r = pam_prompt(handle, PAM_PROMPT_ECHO_OFF, &newp, "Sorry, retry 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_token_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;
assert(secret);
(void) pam_prompt(handle, PAM_ERROR_MSG, NULL, "Security token PIN of user %s incorrect (only one try left!)", user_name);
r = pam_prompt(handle, PAM_PROMPT_ECHO_OFF, &newp, "Sorry, retry 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_token_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;
_cleanup_free_ char *fd_field = NULL;
const void *home_fd_ptr = NULL;
const char *username = 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. */
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;
}
/* If we already have acquired the fd, let's shortcut this */
fd_field = strjoin("systemd-home-fd-", username);
if (!fd_field)
return pam_log_oom(handle);
r = pam_get_data(handle, fd_field, &home_fd_ptr);
if (!IN_SET(r, PAM_SUCCESS, PAM_NO_MODULE_DATA)) {
pam_syslog(handle, LOG_ERR, "Failed to retrieve PAM home reference fd: %s", pam_strerror(handle, r));
return r;
}
if (r == PAM_SUCCESS && PTR_TO_FD(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, username, &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 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 = bus_message_new_method_call(bus, &m, bus_home_mgr, 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;
}
/* Later PAM modules may need the auth token, but only during pam_authenticate. */
if (please_authenticate && !strv_isempty(secret->password)) {
r = pam_set_item(handle, PAM_AUTHTOK, *secret->password);
if (r < 0) {
pam_syslog(handle, LOG_ERR, "Failed to set PAM auth token: %s", pam_strerror(handle, r));
return r;
}
}
r = pam_set_data(handle, fd_field, 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, ur->user_name);
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 char *username) {
_cleanup_free_ char *fd_field = NULL;
const void *home_fd_ptr = NULL;
int r;
assert(handle);
assert(username);
fd_field = strjoin("systemd-home-fd-", username);
if (!fd_field)
return pam_log_oom(handle);
r = pam_get_data(handle, fd_field, &home_fd_ptr);
if (r == PAM_NO_MODULE_DATA || (r == PAM_SUCCESS && PTR_TO_FD(home_fd_ptr) < 0))
return PAM_NO_MODULE_DATA;
if (r != PAM_SUCCESS) {
pam_syslog(handle, LOG_ERR, "Failed to retrieve PAM home reference fd: %s", pam_strerror(handle, r));
return r;
}
r = pam_set_data(handle, fd_field, 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_env(handle, &suspend_please) < 0)
return PAM_AUTH_ERR;
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_env(handle, &suspend_please) < 0)
return PAM_SESSION_ERR;
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;
}
r = pam_putenv(handle, suspend_please ? "SYSTEMD_HOME_SUSPEND=1" : "SYSTEMD_HOME_SUSPEND=0");
if (r != PAM_SUCCESS) {
pam_syslog(handle, LOG_ERR, "Failed to set PAM environment variable $SYSTEMD_HOME_SUSPEND: %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");
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 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, username);
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_acquire_bus_connection(handle, &bus);
if (r != PAM_SUCCESS)
return r;
r = bus_message_new_method_call(bus, &m, bus_home_mgr, "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_env(handle, &please_suspend) < 0)
return PAM_AUTH_ERR;
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_SUCCESS)
return r;
r = acquire_user_record(handle, NULL, &ur);
if (r != PAM_SUCCESS)
return r;
r = user_record_test_blocked(ur);
switch (r) {
case -ESTALE:
pam_syslog(handle, LOG_WARNING, "User record for '%s' is newer than current system time, assuming incorrect system clock, allowing access.", ur->user_name);
break;
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 required.");
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 -ESTALE:
/* If the system clock is wrong, let's log but continue */
pam_syslog(handle, LOG_WARNING, "Couldn't check if password change is required, last change is in the future, system clock likely wrong.");
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, NULL, &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 = bus_message_new_method_call(bus, &m, bus_home_mgr, "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;
}