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Systemd/src/login/pam-module.c

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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <errno.h>
#include <fcntl.h>
#include <sys/file.h>
#include <pwd.h>
#include <endian.h>
#include <sys/capability.h>
#include <security/pam_modules.h>
#include <security/_pam_macros.h>
#include <security/pam_modutil.h>
#include <security/pam_ext.h>
#include <security/pam_misc.h>
#include <systemd/sd-daemon.h>
#include "util.h"
#include "audit.h"
#include "macro.h"
#include "strv.h"
#include "dbus-common.h"
#include "def.h"
#include "socket-util.h"
static int parse_argv(pam_handle_t *handle,
int argc, const char **argv,
char ***controllers,
char ***reset_controllers,
bool *kill_processes,
char ***kill_only_users,
char ***kill_exclude_users,
bool *debug) {
unsigned i;
assert(argc >= 0);
assert(argc == 0 || argv);
for (i = 0; i < (unsigned) argc; i++) {
int k;
if (startswith(argv[i], "kill-session-processes=")) {
if ((k = parse_boolean(argv[i] + 23)) < 0) {
pam_syslog(handle, LOG_ERR, "Failed to parse kill-session-processes= argument.");
return k;
}
if (kill_processes)
*kill_processes = k;
} else if (startswith(argv[i], "kill-session=")) {
/* As compatibility for old versions */
if ((k = parse_boolean(argv[i] + 13)) < 0) {
pam_syslog(handle, LOG_ERR, "Failed to parse kill-session= argument.");
return k;
}
if (kill_processes)
*kill_processes = k;
} else if (startswith(argv[i], "controllers=")) {
if (controllers) {
char **l;
if (!(l = strv_split(argv[i] + 12, ","))) {
pam_syslog(handle, LOG_ERR, "Out of memory.");
return -ENOMEM;
}
strv_free(*controllers);
*controllers = l;
}
} else if (startswith(argv[i], "reset-controllers=")) {
if (reset_controllers) {
char **l;
if (!(l = strv_split(argv[i] + 18, ","))) {
pam_syslog(handle, LOG_ERR, "Out of memory.");
return -ENOMEM;
}
strv_free(*reset_controllers);
*reset_controllers = l;
}
} else if (startswith(argv[i], "kill-only-users=")) {
if (kill_only_users) {
char **l;
if (!(l = strv_split(argv[i] + 16, ","))) {
pam_syslog(handle, LOG_ERR, "Out of memory.");
return -ENOMEM;
}
strv_free(*kill_only_users);
*kill_only_users = l;
}
} else if (startswith(argv[i], "kill-exclude-users=")) {
if (kill_exclude_users) {
char **l;
if (!(l = strv_split(argv[i] + 19, ","))) {
pam_syslog(handle, LOG_ERR, "Out of memory.");
return -ENOMEM;
}
strv_free(*kill_exclude_users);
*kill_exclude_users = l;
}
} else if (startswith(argv[i], "debug=")) {
if ((k = parse_boolean(argv[i] + 6)) < 0) {
pam_syslog(handle, LOG_ERR, "Failed to parse debug= argument.");
return k;
}
if (debug)
*debug = k;
} else if (startswith(argv[i], "create-session=") ||
startswith(argv[i], "kill-user=")) {
pam_syslog(handle, LOG_WARNING, "Option %s not supported anymore, ignoring.", argv[i]);
} else {
pam_syslog(handle, LOG_ERR, "Unknown parameter '%s'.", argv[i]);
return -EINVAL;
}
}
return 0;
}
static int get_user_data(
pam_handle_t *handle,
const char **ret_username,
struct passwd **ret_pw) {
const char *username = NULL;
struct passwd *pw = NULL;
uid_t uid;
int r;
assert(handle);
assert(ret_username);
assert(ret_pw);
r = audit_loginuid_from_pid(0, &uid);
if (r >= 0)
pw = pam_modutil_getpwuid(handle, uid);
else {
r = pam_get_user(handle, &username, NULL);
if (r != PAM_SUCCESS) {
pam_syslog(handle, LOG_ERR, "Failed to get user name.");
return r;
}
if (isempty(username)) {
pam_syslog(handle, LOG_ERR, "User name not valid.");
return PAM_AUTH_ERR;
}
pw = pam_modutil_getpwnam(handle, username);
}
if (!pw) {
pam_syslog(handle, LOG_ERR, "Failed to get user data.");
return PAM_USER_UNKNOWN;
}
*ret_pw = pw;
*ret_username = username ? username : pw->pw_name;
return PAM_SUCCESS;
}
static bool check_user_lists(
pam_handle_t *handle,
uid_t uid,
char **kill_only_users,
char **kill_exclude_users) {
const char *name = NULL;
char **l;
assert(handle);
if (uid == 0)
name = "root"; /* Avoid obvious NSS requests, to suppress network traffic */
else {
struct passwd *pw;
pw = pam_modutil_getpwuid(handle, uid);
if (pw)
name = pw->pw_name;
}
STRV_FOREACH(l, kill_exclude_users) {
uid_t u;
if (parse_uid(*l, &u) >= 0)
if (u == uid)
return false;
if (name && streq(name, *l))
return false;
}
if (strv_isempty(kill_only_users))
return true;
STRV_FOREACH(l, kill_only_users) {
uid_t u;
if (parse_uid(*l, &u) >= 0)
if (u == uid)
return true;
if (name && streq(name, *l))
return true;
}
return false;
}
static int get_seat_from_display(const char *display, const char **seat, uint32_t *vtnr) {
char *p = NULL;
int r;
int fd;
union sockaddr_union sa;
struct ucred ucred;
socklen_t l;
char *tty;
int v;
assert(display);
assert(vtnr);
/* We deduce the X11 socket from the display name, then use
* SO_PEERCRED to determine the X11 server process, ask for
* the controlling tty of that and if it's a VC then we know
* the seat and the virtual terminal. Sounds ugly, is only
* semi-ugly. */
r = socket_from_display(display, &p);
if (r < 0)
return r;
fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0);
if (fd < 0) {
free(p);
return -errno;
}
zero(sa);
sa.un.sun_family = AF_UNIX;
strncpy(sa.un.sun_path, p, sizeof(sa.un.sun_path)-1);
free(p);
if (connect(fd, &sa.sa, offsetof(struct sockaddr_un, sun_path) + strlen(sa.un.sun_path)) < 0) {
close_nointr_nofail(fd);
return -errno;
}
l = sizeof(ucred);
r = getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &ucred, &l);
close_nointr_nofail(fd);
if (r < 0)
return -errno;
r = get_ctty(ucred.pid, NULL, &tty);
if (r < 0)
return r;
v = vtnr_from_tty(tty);
free(tty);
if (v < 0)
return v;
else if (v == 0)
return -ENOENT;
if (seat)
*seat = "seat0";
*vtnr = (uint32_t) v;
return 0;
}
_public_ PAM_EXTERN int pam_sm_open_session(
pam_handle_t *handle,
int flags,
int argc, const char **argv) {
struct passwd *pw;
bool kill_processes = false, debug = false;
const char *username, *id, *object_path, *runtime_path, *service = NULL, *tty = NULL, *display = NULL, *remote_user = NULL, *remote_host = NULL, *seat = NULL, *type, *class, *cvtnr = NULL;
char **controllers = NULL, **reset_controllers = NULL, **kill_only_users = NULL, **kill_exclude_users = NULL;
DBusError error;
uint32_t uid, pid;
DBusMessageIter iter;
dbus_bool_t kp;
int session_fd = -1;
DBusConnection *bus = NULL;
DBusMessage *m = NULL, *reply = NULL;
dbus_bool_t remote, existing;
int r;
uint32_t vtnr = 0;
assert(handle);
dbus_error_init(&error);
/* pam_syslog(handle, LOG_INFO, "pam-systemd initializing"); */
/* Make this a NOP on non-systemd systems */
if (sd_booted() <= 0)
return PAM_SUCCESS;
if (parse_argv(handle,
argc, argv,
&controllers, &reset_controllers,
&kill_processes, &kill_only_users, &kill_exclude_users,
&debug) < 0) {
r = PAM_SESSION_ERR;
goto finish;
}
r = get_user_data(handle, &username, &pw);
if (r != PAM_SUCCESS)
goto finish;
/* Make sure we don't enter a loop by talking to
* systemd-logind when it is actually waiting for the
* background to finish start-up. If the service is
* "systemd-shared" we simply set XDG_RUNTIME_DIR and
* leave. */
pam_get_item(handle, PAM_SERVICE, (const void**) &service);
if (streq_ptr(service, "systemd-shared")) {
char *p, *rt = NULL;
if (asprintf(&p, "/run/systemd/users/%lu", (unsigned long) pw->pw_uid) < 0) {
r = PAM_BUF_ERR;
goto finish;
}
r = parse_env_file(p, NEWLINE,
"RUNTIME", &rt,
NULL);
free(p);
if (r < 0 && r != -ENOENT) {
r = PAM_SESSION_ERR;
free(rt);
goto finish;
}
if (rt) {
r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", rt, 0);
free(rt);
if (r != PAM_SUCCESS) {
pam_syslog(handle, LOG_ERR, "Failed to set runtime dir.");
goto finish;
}
}
r = PAM_SUCCESS;
goto finish;
}
if (kill_processes)
kill_processes = check_user_lists(handle, pw->pw_uid, kill_only_users, kill_exclude_users);
dbus_connection_set_change_sigpipe(FALSE);
bus = dbus_bus_get_private(DBUS_BUS_SYSTEM, &error);
if (!bus) {
pam_syslog(handle, LOG_ERR, "Failed to connect to system bus: %s", bus_error_message(&error));
r = PAM_SESSION_ERR;
goto finish;
}
m = dbus_message_new_method_call(
"org.freedesktop.login1",
"/org/freedesktop/login1",
"org.freedesktop.login1.Manager",
"CreateSession");
if (!m) {
pam_syslog(handle, LOG_ERR, "Could not allocate create session message.");
r = PAM_BUF_ERR;
goto finish;
}
uid = pw->pw_uid;
pid = getpid();
pam_get_item(handle, PAM_XDISPLAY, (const void**) &display);
pam_get_item(handle, PAM_TTY, (const void**) &tty);
pam_get_item(handle, PAM_RUSER, (const void**) &remote_user);
pam_get_item(handle, PAM_RHOST, (const void**) &remote_host);
seat = pam_getenv(handle, "XDG_SEAT");
if (isempty(seat))
seat = getenv("XDG_SEAT");
cvtnr = pam_getenv(handle, "XDG_VTNR");
if (isempty(cvtnr))
cvtnr = getenv("XDG_VTNR");
service = strempty(service);
tty = strempty(tty);
display = strempty(display);
remote_user = strempty(remote_user);
remote_host = strempty(remote_host);
seat = strempty(seat);
if (strchr(tty, ':')) {
/* A tty with a colon is usually an X11 display, place
* there to show up in utmp. We rearrange things and
* don't pretend that an X display was a tty */
if (isempty(display))
display = tty;
tty = "";
} else if (streq(tty, "cron")) {
/* cron has been setting PAM_TTY to "cron" for a very long time
* and it cannot stop doing that for compatibility reasons. */
tty = "";
}
/* If this fails vtnr will be 0, that's intended */
if (!isempty(cvtnr))
safe_atou32(cvtnr, &vtnr);
if (!isempty(display) && vtnr <= 0) {
if (isempty(seat))
get_seat_from_display(display, &seat, &vtnr);
else if (streq(seat, "seat0"))
get_seat_from_display(display, NULL, &vtnr);
}
type = !isempty(display) ? "x11" :
!isempty(tty) ? "tty" : "unspecified";
class = pam_getenv(handle, "XDG_SESSION_CLASS");
if (isempty(class))
class = getenv("XDG_SESSION_CLASS");
if (isempty(class))
class = "user";
remote = !isempty(remote_host) &&
!streq(remote_host, "localhost") &&
!streq(remote_host, "localhost.localdomain");
if (!dbus_message_append_args(m,
DBUS_TYPE_UINT32, &uid,
DBUS_TYPE_UINT32, &pid,
DBUS_TYPE_STRING, &service,
DBUS_TYPE_STRING, &type,
DBUS_TYPE_STRING, &class,
DBUS_TYPE_STRING, &seat,
DBUS_TYPE_UINT32, &vtnr,
DBUS_TYPE_STRING, &tty,
DBUS_TYPE_STRING, &display,
DBUS_TYPE_BOOLEAN, &remote,
DBUS_TYPE_STRING, &remote_user,
DBUS_TYPE_STRING, &remote_host,
DBUS_TYPE_INVALID)) {
pam_syslog(handle, LOG_ERR, "Could not attach parameters to message.");
r = PAM_BUF_ERR;
goto finish;
}
dbus_message_iter_init_append(m, &iter);
r = bus_append_strv_iter(&iter, controllers);
if (r < 0) {
pam_syslog(handle, LOG_ERR, "Could not attach parameter to message.");
r = PAM_BUF_ERR;
goto finish;
}
r = bus_append_strv_iter(&iter, reset_controllers);
if (r < 0) {
pam_syslog(handle, LOG_ERR, "Could not attach parameter to message.");
r = PAM_BUF_ERR;
goto finish;
}
kp = kill_processes;
if (!dbus_message_iter_append_basic(&iter, DBUS_TYPE_BOOLEAN, &kp)) {
pam_syslog(handle, LOG_ERR, "Could not attach parameter to message.");
r = PAM_BUF_ERR;
goto finish;
}
if (debug)
pam_syslog(handle, LOG_DEBUG, "Asking logind to create session: "
"uid=%u pid=%u service=%s type=%s class=%s seat=%s vtnr=%u tty=%s display=%s remote=%s remote_user=%s remote_host=%s",
uid, pid, service, type, class, seat, vtnr, tty, display, yes_no(remote), remote_user, remote_host);
reply = dbus_connection_send_with_reply_and_block(bus, m, -1, &error);
if (!reply) {
pam_syslog(handle, LOG_ERR, "Failed to create session: %s", bus_error_message(&error));
r = PAM_SESSION_ERR;
goto finish;
}
if (!dbus_message_get_args(reply, &error,
DBUS_TYPE_STRING, &id,
DBUS_TYPE_OBJECT_PATH, &object_path,
DBUS_TYPE_STRING, &runtime_path,
DBUS_TYPE_UNIX_FD, &session_fd,
DBUS_TYPE_STRING, &seat,
DBUS_TYPE_UINT32, &vtnr,
DBUS_TYPE_BOOLEAN, &existing,
DBUS_TYPE_INVALID)) {
pam_syslog(handle, LOG_ERR, "Failed to parse message: %s", bus_error_message(&error));
r = PAM_SESSION_ERR;
goto finish;
}
if (debug)
pam_syslog(handle, LOG_DEBUG, "Reply from logind: "
"id=%s object_path=%s runtime_path=%s session_fd=%d seat=%s vtnr=%u",
id, object_path, runtime_path, session_fd, seat, vtnr);
r = pam_misc_setenv(handle, "XDG_SESSION_ID", id, 0);
if (r != PAM_SUCCESS) {
pam_syslog(handle, LOG_ERR, "Failed to set session id.");
goto finish;
}
r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", runtime_path, 0);
if (r != PAM_SUCCESS) {
pam_syslog(handle, LOG_ERR, "Failed to set runtime dir.");
goto finish;
}
if (!isempty(seat)) {
r = pam_misc_setenv(handle, "XDG_SEAT", seat, 0);
if (r != PAM_SUCCESS) {
pam_syslog(handle, LOG_ERR, "Failed to set seat.");
goto finish;
}
}
if (vtnr > 0) {
char buf[11];
snprintf(buf, sizeof(buf), "%u", vtnr);
char_array_0(buf);
r = pam_misc_setenv(handle, "XDG_VTNR", buf, 0);
if (r != PAM_SUCCESS) {
pam_syslog(handle, LOG_ERR, "Failed to set virtual terminal number.");
goto finish;
}
}
r = pam_set_data(handle, "systemd.existing", INT_TO_PTR(!!existing), NULL);
if (r != PAM_SUCCESS) {
pam_syslog(handle, LOG_ERR, "Failed to install existing flag.");
return r;
}
if (session_fd >= 0) {
r = pam_set_data(handle, "systemd.session-fd", INT_TO_PTR(session_fd+1), NULL);
if (r != PAM_SUCCESS) {
pam_syslog(handle, LOG_ERR, "Failed to install session fd.");
return r;
}
}
session_fd = -1;
r = PAM_SUCCESS;
finish:
strv_free(controllers);
strv_free(reset_controllers);
strv_free(kill_only_users);
strv_free(kill_exclude_users);
dbus_error_free(&error);
if (bus) {
dbus_connection_close(bus);
dbus_connection_unref(bus);
}
if (m)
dbus_message_unref(m);
if (reply)
dbus_message_unref(reply);
if (session_fd >= 0)
close_nointr_nofail(session_fd);
return r;
}
_public_ PAM_EXTERN int pam_sm_close_session(
pam_handle_t *handle,
int flags,
int argc, const char **argv) {
const void *p = NULL, *existing = NULL;
const char *id;
DBusConnection *bus = NULL;
DBusMessage *m = NULL, *reply = NULL;
DBusError error;
int r;
assert(handle);
dbus_error_init(&error);
/* Only release session if it wasn't pre-existing when we
* tried to create it */
pam_get_data(handle, "systemd.existing", &existing);
id = pam_getenv(handle, "XDG_SESSION_ID");
if (id && !existing) {
/* Before we go and close the FIFO we need to tell
* logind that this is a clean session shutdown, so
* that it doesn't just go and slaughter us
* immediately after closing the fd */
bus = dbus_bus_get_private(DBUS_BUS_SYSTEM, &error);
if (!bus) {
pam_syslog(handle, LOG_ERR, "Failed to connect to system bus: %s", bus_error_message(&error));
r = PAM_SESSION_ERR;
goto finish;
}
m = dbus_message_new_method_call(
"org.freedesktop.login1",
"/org/freedesktop/login1",
"org.freedesktop.login1.Manager",
"ReleaseSession");
if (!m) {
pam_syslog(handle, LOG_ERR, "Could not allocate release session message.");
r = PAM_BUF_ERR;
goto finish;
}
if (!dbus_message_append_args(m,
DBUS_TYPE_STRING, &id,
DBUS_TYPE_INVALID)) {
pam_syslog(handle, LOG_ERR, "Could not attach parameters to message.");
r = PAM_BUF_ERR;
goto finish;
}
reply = dbus_connection_send_with_reply_and_block(bus, m, -1, &error);
if (!reply) {
pam_syslog(handle, LOG_ERR, "Failed to release session: %s", bus_error_message(&error));
r = PAM_SESSION_ERR;
goto finish;
}
}
r = PAM_SUCCESS;
finish:
pam_get_data(handle, "systemd.session-fd", &p);
if (p)
close_nointr(PTR_TO_INT(p) - 1);
dbus_error_free(&error);
if (bus) {
dbus_connection_close(bus);
dbus_connection_unref(bus);
}
if (m)
dbus_message_unref(m);
if (reply)
dbus_message_unref(reply);
return r;
}
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