1 /* SPDX-License-Identifier: LGPL-2.1+ */
9 #include "alloc-util.h"
10 #include "bus-common-errors.h"
12 #include "errno-util.h"
13 #include "hostname-util.h"
14 #include "in-addr-util.h"
16 #include "memory-util.h"
18 #include "signal-util.h"
19 #include "string-util.h"
20 #include "user-util.h"
22 NSS_GETHOSTBYNAME_PROTOTYPES(mymachines
);
23 NSS_GETPW_PROTOTYPES(mymachines
);
24 NSS_GETGR_PROTOTYPES(mymachines
);
26 #define HOST_UID_LIMIT ((uid_t) UINT32_C(0x10000))
27 #define HOST_GID_LIMIT ((gid_t) UINT32_C(0x10000))
29 static int count_addresses(sd_bus_message
*m
, int af
, unsigned *ret
) {
36 while ((r
= sd_bus_message_enter_container(m
, 'r', "iay")) > 0) {
39 r
= sd_bus_message_read(m
, "i", &family
);
43 r
= sd_bus_message_skip(m
, "ay");
47 r
= sd_bus_message_exit_container(m
);
51 if (af
!= AF_UNSPEC
&& family
!= af
)
59 r
= sd_bus_message_rewind(m
, false);
67 static bool avoid_deadlock(void) {
69 /* Check whether this lookup might have a chance of deadlocking because we are called from the service manager
70 * code activating systemd-machined.service. After all, we shouldn't synchronously do lookups to
71 * systemd-machined if we are required to finish before it can be started. This of course won't detect all
72 * possible dead locks of this kind, but it should work for the most obvious cases. */
74 if (geteuid() != 0) /* Ignore the env vars unless we are privileged. */
77 return streq_ptr(getenv("SYSTEMD_ACTIVATION_UNIT"), "systemd-machined.service") &&
78 streq_ptr(getenv("SYSTEMD_ACTIVATION_SCOPE"), "system");
81 enum nss_status
_nss_mymachines_gethostbyname4_r(
83 struct gaih_addrtuple
**pat
,
84 char *buffer
, size_t buflen
,
85 int *errnop
, int *h_errnop
,
88 struct gaih_addrtuple
*r_tuple
, *r_tuple_first
= NULL
;
89 _cleanup_(sd_bus_message_unrefp
) sd_bus_message
* reply
= NULL
;
90 _cleanup_(sd_bus_flush_close_unrefp
) sd_bus
*bus
= NULL
;
91 _cleanup_free_
int *ifindices
= NULL
;
92 _cleanup_free_
char *class = NULL
;
94 unsigned i
= 0, c
= 0;
99 BLOCK_SIGNALS(NSS_SIGNALS_BLOCK
);
107 r
= sd_machine_get_class(name
, &class);
110 if (!streq(class, "container")) {
115 n_ifindices
= sd_machine_get_ifindices(name
, &ifindices
);
116 if (n_ifindices
< 0) {
121 if (avoid_deadlock()) {
126 r
= sd_bus_open_system(&bus
);
130 r
= sd_bus_call_method(bus
,
131 "org.freedesktop.machine1",
132 "/org/freedesktop/machine1",
133 "org.freedesktop.machine1.Manager",
134 "GetMachineAddresses",
141 r
= sd_bus_message_enter_container(reply
, 'a', "(iay)");
145 r
= count_addresses(reply
, AF_UNSPEC
, &c
);
150 *h_errnop
= HOST_NOT_FOUND
;
151 return NSS_STATUS_NOTFOUND
;
155 ms
= ALIGN(l
+1) + ALIGN(sizeof(struct gaih_addrtuple
)) * c
;
159 *h_errnop
= NETDB_INTERNAL
;
160 return NSS_STATUS_TRYAGAIN
;
163 /* First, append name */
165 memcpy(r_name
, name
, l
+1);
168 /* Second, append addresses */
169 r_tuple_first
= (struct gaih_addrtuple
*) (buffer
+ idx
);
170 while ((r
= sd_bus_message_enter_container(reply
, 'r', "iay")) > 0) {
175 r
= sd_bus_message_read(reply
, "i", &family
);
179 r
= sd_bus_message_read_array(reply
, 'y', &a
, &sz
);
183 r
= sd_bus_message_exit_container(reply
);
187 if (!IN_SET(family
, AF_INET
, AF_INET6
)) {
192 if (sz
!= FAMILY_ADDRESS_SIZE(family
)) {
197 r_tuple
= (struct gaih_addrtuple
*) (buffer
+ idx
);
198 r_tuple
->next
= i
== c
-1 ? NULL
: (struct gaih_addrtuple
*) ((char*) r_tuple
+ ALIGN(sizeof(struct gaih_addrtuple
)));
199 r_tuple
->name
= r_name
;
200 r_tuple
->family
= family
;
201 r_tuple
->scopeid
= n_ifindices
== 1 ? ifindices
[0] : 0;
202 memcpy(r_tuple
->addr
, a
, sz
);
204 idx
+= ALIGN(sizeof(struct gaih_addrtuple
));
210 r
= sd_bus_message_exit_container(reply
);
217 **pat
= *r_tuple_first
;
219 *pat
= r_tuple_first
;
224 /* Explicitly reset both *h_errnop and h_errno to work around
225 * https://bugzilla.redhat.com/show_bug.cgi?id=1125975 */
226 *h_errnop
= NETDB_SUCCESS
;
229 return NSS_STATUS_SUCCESS
;
235 return NSS_STATUS_UNAVAIL
;
238 enum nss_status
_nss_mymachines_gethostbyname3_r(
241 struct hostent
*result
,
242 char *buffer
, size_t buflen
,
243 int *errnop
, int *h_errnop
,
247 _cleanup_(sd_bus_message_unrefp
) sd_bus_message
* reply
= NULL
;
248 _cleanup_(sd_bus_flush_close_unrefp
) sd_bus
*bus
= NULL
;
249 _cleanup_free_
char *class = NULL
;
250 unsigned c
= 0, i
= 0;
251 char *r_name
, *r_aliases
, *r_addr
, *r_addr_list
;
252 size_t l
, idx
, ms
, alen
;
256 BLOCK_SIGNALS(NSS_SIGNALS_BLOCK
);
267 if (af
!= AF_INET
&& af
!= AF_INET6
) {
272 r
= sd_machine_get_class(name
, &class);
275 if (!streq(class, "container")) {
280 if (avoid_deadlock()) {
285 r
= sd_bus_open_system(&bus
);
289 r
= sd_bus_call_method(bus
,
290 "org.freedesktop.machine1",
291 "/org/freedesktop/machine1",
292 "org.freedesktop.machine1.Manager",
293 "GetMachineAddresses",
300 r
= sd_bus_message_enter_container(reply
, 'a', "(iay)");
304 r
= count_addresses(reply
, af
, &c
);
309 *h_errnop
= HOST_NOT_FOUND
;
310 return NSS_STATUS_NOTFOUND
;
313 alen
= FAMILY_ADDRESS_SIZE(af
);
316 ms
= ALIGN(l
+1) + c
* ALIGN(alen
) + (c
+2) * sizeof(char*);
321 *h_errnop
= NETDB_INTERNAL
;
322 return NSS_STATUS_TRYAGAIN
;
325 /* First, append name */
327 memcpy(r_name
, name
, l
+1);
330 /* Second, create aliases array */
331 r_aliases
= buffer
+ idx
;
332 ((char**) r_aliases
)[0] = NULL
;
333 idx
+= sizeof(char*);
335 /* Third, append addresses */
336 r_addr
= buffer
+ idx
;
337 while ((r
= sd_bus_message_enter_container(reply
, 'r', "iay")) > 0) {
342 r
= sd_bus_message_read(reply
, "i", &family
);
346 r
= sd_bus_message_read_array(reply
, 'y', &a
, &sz
);
350 r
= sd_bus_message_exit_container(reply
);
362 memcpy(r_addr
+ i
*ALIGN(alen
), a
, alen
);
367 idx
+= c
* ALIGN(alen
);
369 r
= sd_bus_message_exit_container(reply
);
373 /* Third, append address pointer array */
374 r_addr_list
= buffer
+ idx
;
375 for (i
= 0; i
< c
; i
++)
376 ((char**) r_addr_list
)[i
] = r_addr
+ i
*ALIGN(alen
);
378 ((char**) r_addr_list
)[i
] = NULL
;
379 idx
+= (c
+1) * sizeof(char*);
383 result
->h_name
= r_name
;
384 result
->h_aliases
= (char**) r_aliases
;
385 result
->h_addrtype
= af
;
386 result
->h_length
= alen
;
387 result
->h_addr_list
= (char**) r_addr_list
;
395 /* Explicitly reset both *h_errnop and h_errno to work around
396 * https://bugzilla.redhat.com/show_bug.cgi?id=1125975 */
397 *h_errnop
= NETDB_SUCCESS
;
400 return NSS_STATUS_SUCCESS
;
406 return NSS_STATUS_UNAVAIL
;
409 NSS_GETHOSTBYNAME_FALLBACKS(mymachines
);
411 enum nss_status
_nss_mymachines_getpwnam_r(
414 char *buffer
, size_t buflen
,
417 _cleanup_(sd_bus_error_free
) sd_bus_error error
= SD_BUS_ERROR_NULL
;
418 _cleanup_(sd_bus_message_unrefp
) sd_bus_message
* reply
= NULL
;
419 _cleanup_(sd_bus_flush_close_unrefp
) sd_bus
*bus
= NULL
;
420 const char *p
, *e
, *machine
;
427 BLOCK_SIGNALS(NSS_SIGNALS_BLOCK
);
432 p
= startswith(name
, "vu-");
434 return NSS_STATUS_NOTFOUND
;
438 return NSS_STATUS_NOTFOUND
;
440 if (e
- p
> HOST_NAME_MAX
- 1) /* -1 for the last dash */
441 return NSS_STATUS_NOTFOUND
;
443 r
= parse_uid(e
+ 1, &uid
);
445 return NSS_STATUS_NOTFOUND
;
447 machine
= strndupa(p
, e
- p
);
448 if (!machine_name_is_valid(machine
))
449 return NSS_STATUS_NOTFOUND
;
451 if (getenv_bool_secure("SYSTEMD_NSS_BYPASS_BUS") > 0)
452 /* Make sure we can't deadlock if we are invoked by dbus-daemon. This way, it won't be able to resolve
453 * these UIDs, but that should be unproblematic as containers should never be able to connect to a bus
454 * running on the host. */
455 return NSS_STATUS_NOTFOUND
;
457 if (avoid_deadlock()) {
462 r
= sd_bus_open_system(&bus
);
466 r
= sd_bus_call_method(bus
,
467 "org.freedesktop.machine1",
468 "/org/freedesktop/machine1",
469 "org.freedesktop.machine1.Manager",
470 "MapFromMachineUser",
474 machine
, (uint32_t) uid
);
476 if (sd_bus_error_has_name(&error
, BUS_ERROR_NO_SUCH_USER_MAPPING
))
477 return NSS_STATUS_NOTFOUND
;
482 r
= sd_bus_message_read(reply
, "u", &mapped
);
486 /* Refuse to work if the mapped address is in the host UID range, or if there was no mapping at all. */
487 if (mapped
< HOST_UID_LIMIT
|| mapped
== uid
)
488 return NSS_STATUS_NOTFOUND
;
494 return NSS_STATUS_TRYAGAIN
;
497 memcpy(buffer
, name
, l
+1);
499 pwd
->pw_name
= buffer
;
500 pwd
->pw_uid
= mapped
;
501 pwd
->pw_gid
= GID_NOBODY
;
502 pwd
->pw_gecos
= buffer
;
503 pwd
->pw_passwd
= (char*) "*"; /* locked */
504 pwd
->pw_dir
= (char*) "/";
505 pwd
->pw_shell
= (char*) "/sbin/nologin";
507 return NSS_STATUS_SUCCESS
;
512 return NSS_STATUS_UNAVAIL
;
515 enum nss_status
_nss_mymachines_getpwuid_r(
518 char *buffer
, size_t buflen
,
521 _cleanup_(sd_bus_error_free
) sd_bus_error error
= SD_BUS_ERROR_NULL
;
522 _cleanup_(sd_bus_message_unrefp
) sd_bus_message
* reply
= NULL
;
523 _cleanup_(sd_bus_flush_close_unrefp
) sd_bus
*bus
= NULL
;
529 BLOCK_SIGNALS(NSS_SIGNALS_BLOCK
);
531 if (!uid_is_valid(uid
))
532 return NSS_STATUS_NOTFOUND
;
534 /* We consider all uids < 65536 host uids */
535 if (uid
< HOST_UID_LIMIT
)
536 return NSS_STATUS_NOTFOUND
;
538 if (getenv_bool_secure("SYSTEMD_NSS_BYPASS_BUS") > 0)
539 return NSS_STATUS_NOTFOUND
;
541 if (avoid_deadlock()) {
546 r
= sd_bus_open_system(&bus
);
550 r
= sd_bus_call_method(bus
,
551 "org.freedesktop.machine1",
552 "/org/freedesktop/machine1",
553 "org.freedesktop.machine1.Manager",
560 if (sd_bus_error_has_name(&error
, BUS_ERROR_NO_SUCH_USER_MAPPING
))
561 return NSS_STATUS_NOTFOUND
;
566 r
= sd_bus_message_read(reply
, "sou", &machine
, NULL
, &mapped
);
571 return NSS_STATUS_NOTFOUND
;
573 if (snprintf(buffer
, buflen
, "vu-%s-" UID_FMT
, machine
, (uid_t
) mapped
) >= (int) buflen
) {
576 return NSS_STATUS_TRYAGAIN
;
579 pwd
->pw_name
= buffer
;
581 pwd
->pw_gid
= GID_NOBODY
;
582 pwd
->pw_gecos
= buffer
;
583 pwd
->pw_passwd
= (char*) "*"; /* locked */
584 pwd
->pw_dir
= (char*) "/";
585 pwd
->pw_shell
= (char*) "/sbin/nologin";
587 return NSS_STATUS_SUCCESS
;
592 return NSS_STATUS_UNAVAIL
;
595 #pragma GCC diagnostic ignored "-Wsizeof-pointer-memaccess"
597 enum nss_status
_nss_mymachines_getgrnam_r(
600 char *buffer
, size_t buflen
,
603 _cleanup_(sd_bus_error_free
) sd_bus_error error
= SD_BUS_ERROR_NULL
;
604 _cleanup_(sd_bus_message_unrefp
) sd_bus_message
* reply
= NULL
;
605 _cleanup_(sd_bus_flush_close_unrefp
) sd_bus
*bus
= NULL
;
606 const char *p
, *e
, *machine
;
613 BLOCK_SIGNALS(NSS_SIGNALS_BLOCK
);
618 p
= startswith(name
, "vg-");
620 return NSS_STATUS_NOTFOUND
;
624 return NSS_STATUS_NOTFOUND
;
626 if (e
- p
> HOST_NAME_MAX
- 1) /* -1 for the last dash */
627 return NSS_STATUS_NOTFOUND
;
629 r
= parse_gid(e
+ 1, &gid
);
631 return NSS_STATUS_NOTFOUND
;
633 machine
= strndupa(p
, e
- p
);
634 if (!machine_name_is_valid(machine
))
635 return NSS_STATUS_NOTFOUND
;
637 if (getenv_bool_secure("SYSTEMD_NSS_BYPASS_BUS") > 0)
638 return NSS_STATUS_NOTFOUND
;
640 if (avoid_deadlock()) {
645 r
= sd_bus_open_system(&bus
);
649 r
= sd_bus_call_method(bus
,
650 "org.freedesktop.machine1",
651 "/org/freedesktop/machine1",
652 "org.freedesktop.machine1.Manager",
653 "MapFromMachineGroup",
657 machine
, (uint32_t) gid
);
659 if (sd_bus_error_has_name(&error
, BUS_ERROR_NO_SUCH_GROUP_MAPPING
))
660 return NSS_STATUS_NOTFOUND
;
665 r
= sd_bus_message_read(reply
, "u", &mapped
);
669 if (mapped
< HOST_GID_LIMIT
|| mapped
== gid
)
670 return NSS_STATUS_NOTFOUND
;
672 l
= sizeof(char*) + strlen(name
) + 1;
676 return NSS_STATUS_TRYAGAIN
;
679 memzero(buffer
, sizeof(char*));
680 strcpy(buffer
+ sizeof(char*), name
);
682 gr
->gr_name
= buffer
+ sizeof(char*);
684 gr
->gr_passwd
= (char*) "*"; /* locked */
685 gr
->gr_mem
= (char**) buffer
;
687 return NSS_STATUS_SUCCESS
;
692 return NSS_STATUS_UNAVAIL
;
695 enum nss_status
_nss_mymachines_getgrgid_r(
698 char *buffer
, size_t buflen
,
701 _cleanup_(sd_bus_error_free
) sd_bus_error error
= SD_BUS_ERROR_NULL
;
702 _cleanup_(sd_bus_message_unrefp
) sd_bus_message
* reply
= NULL
;
703 _cleanup_(sd_bus_flush_close_unrefp
) sd_bus
*bus
= NULL
;
709 BLOCK_SIGNALS(NSS_SIGNALS_BLOCK
);
711 if (!gid_is_valid(gid
))
712 return NSS_STATUS_NOTFOUND
;
714 /* We consider all gids < 65536 host gids */
715 if (gid
< HOST_GID_LIMIT
)
716 return NSS_STATUS_NOTFOUND
;
718 if (getenv_bool_secure("SYSTEMD_NSS_BYPASS_BUS") > 0)
719 return NSS_STATUS_NOTFOUND
;
721 if (avoid_deadlock()) {
726 r
= sd_bus_open_system(&bus
);
730 r
= sd_bus_call_method(bus
,
731 "org.freedesktop.machine1",
732 "/org/freedesktop/machine1",
733 "org.freedesktop.machine1.Manager",
740 if (sd_bus_error_has_name(&error
, BUS_ERROR_NO_SUCH_GROUP_MAPPING
))
741 return NSS_STATUS_NOTFOUND
;
746 r
= sd_bus_message_read(reply
, "sou", &machine
, NULL
, &mapped
);
751 return NSS_STATUS_NOTFOUND
;
753 if (buflen
< sizeof(char*) + 1) {
756 return NSS_STATUS_TRYAGAIN
;
759 memzero(buffer
, sizeof(char*));
760 if (snprintf(buffer
+ sizeof(char*), buflen
- sizeof(char*), "vg-%s-" GID_FMT
, machine
, (gid_t
) mapped
) >= (int) buflen
) {
763 return NSS_STATUS_TRYAGAIN
;
766 gr
->gr_name
= buffer
+ sizeof(char*);
768 gr
->gr_passwd
= (char*) "*"; /* locked */
769 gr
->gr_mem
= (char**) buffer
;
771 return NSS_STATUS_SUCCESS
;
776 return NSS_STATUS_UNAVAIL
;