1 /* SPDX-License-Identifier: LGPL-2.1+ */
3 This file is part of systemd.
5 Copyright 2010 Lennart Poettering
12 #include <security/_pam_macros.h>
13 #include <security/pam_ext.h>
14 #include <security/pam_misc.h>
15 #include <security/pam_modules.h>
16 #include <security/pam_modutil.h>
19 #include "alloc-util.h"
20 #include "audit-util.h"
21 #include "bus-common-errors.h"
22 #include "bus-error.h"
27 #include "format-util.h"
28 #include "hostname-util.h"
29 #include "login-util.h"
31 #include "parse-util.h"
32 #include "process-util.h"
33 #include "socket-util.h"
35 #include "terminal-util.h"
37 #include "path-util.h"
39 static int parse_argv(
41 int argc
, const char **argv
,
49 assert(argc
== 0 || argv
);
51 for (i
= 0; i
< (unsigned) argc
; i
++) {
52 if (startswith(argv
[i
], "class=")) {
56 } else if (startswith(argv
[i
], "type=")) {
60 } else if (streq(argv
[i
], "debug")) {
64 } else if (startswith(argv
[i
], "debug=")) {
67 k
= parse_boolean(argv
[i
] + 6);
69 pam_syslog(handle
, LOG_WARNING
, "Failed to parse debug= argument, ignoring.");
74 pam_syslog(handle
, LOG_WARNING
, "Unknown parameter '%s', ignoring", argv
[i
]);
80 static int get_user_data(
82 const char **ret_username
,
83 struct passwd
**ret_pw
) {
85 const char *username
= NULL
;
86 struct passwd
*pw
= NULL
;
93 r
= pam_get_user(handle
, &username
, NULL
);
94 if (r
!= PAM_SUCCESS
) {
95 pam_syslog(handle
, LOG_ERR
, "Failed to get user name.");
99 if (isempty(username
)) {
100 pam_syslog(handle
, LOG_ERR
, "User name not valid.");
104 pw
= pam_modutil_getpwnam(handle
, username
);
106 pam_syslog(handle
, LOG_ERR
, "Failed to get user data.");
107 return PAM_USER_UNKNOWN
;
111 *ret_username
= username
;
116 static int get_seat_from_display(const char *display
, const char **seat
, uint32_t *vtnr
) {
117 union sockaddr_union sa
= {
118 .un
.sun_family
= AF_UNIX
,
120 _cleanup_free_
char *p
= NULL
, *tty
= NULL
;
121 _cleanup_close_
int fd
= -1;
128 /* We deduce the X11 socket from the display name, then use
129 * SO_PEERCRED to determine the X11 server process, ask for
130 * the controlling tty of that and if it's a VC then we know
131 * the seat and the virtual terminal. Sounds ugly, is only
134 r
= socket_from_display(display
, &p
);
137 strncpy(sa
.un
.sun_path
, p
, sizeof(sa
.un
.sun_path
)-1);
139 fd
= socket(AF_UNIX
, SOCK_STREAM
|SOCK_CLOEXEC
, 0);
143 if (connect(fd
, &sa
.sa
, SOCKADDR_UN_LEN(sa
.un
)) < 0)
146 r
= getpeercred(fd
, &ucred
);
150 r
= get_ctty(ucred
.pid
, NULL
, &tty
);
154 v
= vtnr_from_tty(tty
);
162 *vtnr
= (uint32_t) v
;
167 static int export_legacy_dbus_address(
168 pam_handle_t
*handle
,
170 const char *runtime
) {
172 _cleanup_free_
char *s
= NULL
;
175 /* FIXME: We *really* should move the access() check into the
176 * daemons that spawn dbus-daemon, instead of forcing
177 * DBUS_SESSION_BUS_ADDRESS= here. */
179 s
= strjoin(runtime
, "/bus");
183 if (access(s
, F_OK
) < 0)
187 if (asprintf(&s
, DEFAULT_USER_BUS_ADDRESS_FMT
, runtime
) < 0)
190 r
= pam_misc_setenv(handle
, "DBUS_SESSION_BUS_ADDRESS", s
, 0);
191 if (r
!= PAM_SUCCESS
)
197 pam_syslog(handle
, LOG_ERR
, "Failed to set bus variable.");
201 _public_ PAM_EXTERN
int pam_sm_open_session(
202 pam_handle_t
*handle
,
204 int argc
, const char **argv
) {
206 _cleanup_(sd_bus_error_free
) sd_bus_error error
= SD_BUS_ERROR_NULL
;
207 _cleanup_(sd_bus_message_unrefp
) sd_bus_message
*reply
= NULL
;
209 *username
, *id
, *object_path
, *runtime_path
,
211 *tty
= NULL
, *display
= NULL
,
212 *remote_user
= NULL
, *remote_host
= NULL
,
214 *type
= NULL
, *class = NULL
,
215 *class_pam
= NULL
, *type_pam
= NULL
, *cvtnr
= NULL
, *desktop
= NULL
;
216 _cleanup_(sd_bus_flush_close_unrefp
) sd_bus
*bus
= NULL
;
217 int session_fd
= -1, existing
, r
;
218 bool debug
= false, remote
;
225 /* Make this a NOP on non-logind systems */
226 if (!logind_running())
229 if (parse_argv(handle
,
234 return PAM_SESSION_ERR
;
237 pam_syslog(handle
, LOG_DEBUG
, "pam-systemd initializing");
239 r
= get_user_data(handle
, &username
, &pw
);
240 if (r
!= PAM_SUCCESS
) {
241 pam_syslog(handle
, LOG_ERR
, "Failed to get user data.");
245 /* Make sure we don't enter a loop by talking to
246 * systemd-logind when it is actually waiting for the
247 * background to finish start-up. If the service is
248 * "systemd-user" we simply set XDG_RUNTIME_DIR and
251 pam_get_item(handle
, PAM_SERVICE
, (const void**) &service
);
252 if (streq_ptr(service
, "systemd-user")) {
253 _cleanup_free_
char *rt
= NULL
;
255 if (asprintf(&rt
, "/run/user/"UID_FMT
, pw
->pw_uid
) < 0)
258 r
= pam_misc_setenv(handle
, "XDG_RUNTIME_DIR", rt
, 0);
259 if (r
!= PAM_SUCCESS
) {
260 pam_syslog(handle
, LOG_ERR
, "Failed to set runtime dir.");
264 r
= export_legacy_dbus_address(handle
, pw
->pw_uid
, rt
);
265 if (r
!= PAM_SUCCESS
)
271 /* Otherwise, we ask logind to create a session for us */
273 pam_get_item(handle
, PAM_XDISPLAY
, (const void**) &display
);
274 pam_get_item(handle
, PAM_TTY
, (const void**) &tty
);
275 pam_get_item(handle
, PAM_RUSER
, (const void**) &remote_user
);
276 pam_get_item(handle
, PAM_RHOST
, (const void**) &remote_host
);
278 seat
= pam_getenv(handle
, "XDG_SEAT");
280 seat
= getenv("XDG_SEAT");
282 cvtnr
= pam_getenv(handle
, "XDG_VTNR");
284 cvtnr
= getenv("XDG_VTNR");
286 type
= pam_getenv(handle
, "XDG_SESSION_TYPE");
288 type
= getenv("XDG_SESSION_TYPE");
292 class = pam_getenv(handle
, "XDG_SESSION_CLASS");
294 class = getenv("XDG_SESSION_CLASS");
298 desktop
= pam_getenv(handle
, "XDG_SESSION_DESKTOP");
299 if (isempty(desktop
))
300 desktop
= getenv("XDG_SESSION_DESKTOP");
304 if (strchr(tty
, ':')) {
305 /* A tty with a colon is usually an X11 display,
306 * placed there to show up in utmp. We rearrange
307 * things and don't pretend that an X display was a
310 if (isempty(display
))
313 } else if (streq(tty
, "cron")) {
314 /* cron has been setting PAM_TTY to "cron" for a very
315 * long time and it probably shouldn't stop doing that
316 * for compatibility reasons. */
317 type
= "unspecified";
318 class = "background";
320 } else if (streq(tty
, "ssh")) {
321 /* ssh has been setting PAM_TTY to "ssh" for a very
322 * long time and probably shouldn't stop doing that
323 * for compatibility reasons. */
328 /* Chop off leading /dev prefix that some clients specify, but others do not. */
329 tty
= skip_dev_prefix(tty
);
331 /* If this fails vtnr will be 0, that's intended */
333 (void) safe_atou32(cvtnr
, &vtnr
);
335 if (!isempty(display
) && !vtnr
) {
337 get_seat_from_display(display
, &seat
, &vtnr
);
338 else if (streq(seat
, "seat0"))
339 get_seat_from_display(display
, NULL
, &vtnr
);
342 if (seat
&& !streq(seat
, "seat0") && vtnr
!= 0) {
343 pam_syslog(handle
, LOG_DEBUG
, "Ignoring vtnr %"PRIu32
" for %s which is not seat0", vtnr
, seat
);
348 type
= !isempty(display
) ? "x11" :
349 !isempty(tty
) ? "tty" : "unspecified";
352 class = streq(type
, "unspecified") ? "background" : "user";
354 remote
= !isempty(remote_host
) && !is_localhost(remote_host
);
356 /* Talk to logind over the message bus */
358 r
= sd_bus_open_system(&bus
);
360 pam_syslog(handle
, LOG_ERR
, "Failed to connect to system bus: %s", strerror(-r
));
361 return PAM_SESSION_ERR
;
365 pam_syslog(handle
, LOG_DEBUG
, "Asking logind to create session: "
366 "uid="UID_FMT
" pid="PID_FMT
" service=%s type=%s class=%s desktop=%s seat=%s vtnr=%"PRIu32
" tty=%s display=%s remote=%s remote_user=%s remote_host=%s",
367 pw
->pw_uid
, getpid_cached(),
369 type
, class, strempty(desktop
),
370 strempty(seat
), vtnr
, strempty(tty
), strempty(display
),
371 yes_no(remote
), strempty(remote_user
), strempty(remote_host
));
373 r
= sd_bus_call_method(bus
,
374 "org.freedesktop.login1",
375 "/org/freedesktop/login1",
376 "org.freedesktop.login1.Manager",
380 "uusssssussbssa(sv)",
381 (uint32_t) pw
->pw_uid
,
382 (uint32_t) getpid_cached(),
396 if (sd_bus_error_has_name(&error
, BUS_ERROR_SESSION_BUSY
)) {
397 pam_syslog(handle
, LOG_DEBUG
, "Cannot create session: %s", bus_error_message(&error
, r
));
400 pam_syslog(handle
, LOG_ERR
, "Failed to create session: %s", bus_error_message(&error
, r
));
401 return PAM_SYSTEM_ERR
;
405 r
= sd_bus_message_read(reply
,
416 pam_syslog(handle
, LOG_ERR
, "Failed to parse message: %s", strerror(-r
));
417 return PAM_SESSION_ERR
;
421 pam_syslog(handle
, LOG_DEBUG
, "Reply from logind: "
422 "id=%s object_path=%s runtime_path=%s session_fd=%d seat=%s vtnr=%u original_uid=%u",
423 id
, object_path
, runtime_path
, session_fd
, seat
, vtnr
, original_uid
);
425 r
= pam_misc_setenv(handle
, "XDG_SESSION_ID", id
, 0);
426 if (r
!= PAM_SUCCESS
) {
427 pam_syslog(handle
, LOG_ERR
, "Failed to set session id.");
431 if (original_uid
== pw
->pw_uid
) {
432 /* Don't set $XDG_RUNTIME_DIR if the user we now
433 * authenticated for does not match the original user
434 * of the session. We do this in order not to result
435 * in privileged apps clobbering the runtime directory
438 r
= pam_misc_setenv(handle
, "XDG_RUNTIME_DIR", runtime_path
, 0);
439 if (r
!= PAM_SUCCESS
) {
440 pam_syslog(handle
, LOG_ERR
, "Failed to set runtime dir.");
444 r
= export_legacy_dbus_address(handle
, pw
->pw_uid
, runtime_path
);
445 if (r
!= PAM_SUCCESS
)
449 if (!isempty(seat
)) {
450 r
= pam_misc_setenv(handle
, "XDG_SEAT", seat
, 0);
451 if (r
!= PAM_SUCCESS
) {
452 pam_syslog(handle
, LOG_ERR
, "Failed to set seat.");
458 char buf
[DECIMAL_STR_MAX(vtnr
)];
459 sprintf(buf
, "%u", vtnr
);
461 r
= pam_misc_setenv(handle
, "XDG_VTNR", buf
, 0);
462 if (r
!= PAM_SUCCESS
) {
463 pam_syslog(handle
, LOG_ERR
, "Failed to set virtual terminal number.");
468 r
= pam_set_data(handle
, "systemd.existing", INT_TO_PTR(!!existing
), NULL
);
469 if (r
!= PAM_SUCCESS
) {
470 pam_syslog(handle
, LOG_ERR
, "Failed to install existing flag.");
474 if (session_fd
>= 0) {
475 session_fd
= fcntl(session_fd
, F_DUPFD_CLOEXEC
, 3);
476 if (session_fd
< 0) {
477 pam_syslog(handle
, LOG_ERR
, "Failed to dup session fd: %m");
478 return PAM_SESSION_ERR
;
481 r
= pam_set_data(handle
, "systemd.session-fd", FD_TO_PTR(session_fd
), NULL
);
482 if (r
!= PAM_SUCCESS
) {
483 pam_syslog(handle
, LOG_ERR
, "Failed to install session fd.");
484 safe_close(session_fd
);
492 _public_ PAM_EXTERN
int pam_sm_close_session(
493 pam_handle_t
*handle
,
495 int argc
, const char **argv
) {
497 _cleanup_(sd_bus_error_free
) sd_bus_error error
= SD_BUS_ERROR_NULL
;
498 _cleanup_(sd_bus_flush_close_unrefp
) sd_bus
*bus
= NULL
;
499 const void *existing
= NULL
;
505 /* Only release session if it wasn't pre-existing when we
506 * tried to create it */
507 pam_get_data(handle
, "systemd.existing", &existing
);
509 id
= pam_getenv(handle
, "XDG_SESSION_ID");
510 if (id
&& !existing
) {
512 /* Before we go and close the FIFO we need to tell
513 * logind that this is a clean session shutdown, so
514 * that it doesn't just go and slaughter us
515 * immediately after closing the fd */
517 r
= sd_bus_open_system(&bus
);
519 pam_syslog(handle
, LOG_ERR
, "Failed to connect to system bus: %s", strerror(-r
));
520 return PAM_SESSION_ERR
;
523 r
= sd_bus_call_method(bus
,
524 "org.freedesktop.login1",
525 "/org/freedesktop/login1",
526 "org.freedesktop.login1.Manager",
533 pam_syslog(handle
, LOG_ERR
, "Failed to release session: %s", bus_error_message(&error
, r
));
534 return PAM_SESSION_ERR
;
538 /* Note that we are knowingly leaking the FIFO fd here. This
539 * way, logind can watch us die. If we closed it here it would
540 * not have any clue when that is completed. Given that one
541 * cannot really have multiple PAM sessions open from the same
542 * process this means we will leak one FD at max. */