1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
12 #include "errno-util.h"
13 #include "glyph-util.h"
14 #include "in-addr-util.h"
17 #include "resolved-def.h"
18 #include "signal-util.h"
19 #include "string-util.h"
23 static JsonDispatchFlags json_dispatch_flags
= 0;
25 static void setup_logging(void) {
26 log_parse_environment_variables();
29 json_dispatch_flags
= JSON_LOG
;
32 static void setup_logging_once(void) {
33 static pthread_once_t once
= PTHREAD_ONCE_INIT
;
34 assert_se(pthread_once(&once
, setup_logging
) == 0);
37 #define NSS_ENTRYPOINT_BEGIN \
38 BLOCK_SIGNALS(NSS_SIGNALS_BLOCK); \
41 NSS_GETHOSTBYNAME_PROTOTYPES(resolve
);
42 NSS_GETHOSTBYADDR_PROTOTYPES(resolve
);
44 static bool error_shall_fallback(const char *error_id
) {
45 /* The Varlink errors where we shall signal "please fallback" back to the NSS stack, so that some
46 * fallback module can be loaded. (These are mostly all Varlink-internal errors, as apparently we
47 * then were unable to even do IPC with systemd-resolved.) */
48 return STR_IN_SET(error_id
,
49 VARLINK_ERROR_DISCONNECTED
,
50 VARLINK_ERROR_TIMEOUT
,
51 VARLINK_ERROR_PROTOCOL
,
52 VARLINK_ERROR_INTERFACE_NOT_FOUND
,
53 VARLINK_ERROR_METHOD_NOT_FOUND
,
54 VARLINK_ERROR_METHOD_NOT_IMPLEMENTED
);
57 static bool error_shall_try_again(const char *error_id
) {
58 /* The Varlink errors where we shall signal "can't answer now but might be able to later" back to the
59 * NSS stack. These are all errors that indicate lack of configuration or network problems. */
60 return STR_IN_SET(error_id
,
61 "io.systemd.Resolve.NoNameServers",
62 "io.systemd.Resolve.QueryTimedOut",
63 "io.systemd.Resolve.MaxAttemptsReached",
64 "io.systemd.Resolve.NetworkDown");
67 static int connect_to_resolved(Varlink
**ret
) {
68 _cleanup_(varlink_unrefp
) Varlink
*link
= NULL
;
71 r
= varlink_connect_address(&link
, "/run/systemd/resolve/io.systemd.Resolve");
75 r
= varlink_set_relative_timeout(link
, SD_RESOLVED_QUERY_TIMEOUT_USEC
);
79 *ret
= TAKE_PTR(link
);
83 static uint32_t ifindex_to_scopeid(int family
, const void *a
, int ifindex
) {
86 if (family
!= AF_INET6
|| ifindex
== 0)
89 /* Some apps can't deal with the scope ID attached to non-link-local addresses. Hence, let's suppress that. */
91 assert(sizeof(in6
) == FAMILY_ADDRESS_SIZE(AF_INET6
));
92 memcpy(&in6
, a
, sizeof(struct in6_addr
));
94 return in6_addr_is_link_local(&in6
) ? ifindex
: 0;
97 static int json_dispatch_ifindex(const char *name
, JsonVariant
*variant
, JsonDispatchFlags flags
, void *userdata
) {
104 if (!json_variant_is_integer(variant
))
105 return json_log(variant
, flags
, SYNTHETIC_ERRNO(EINVAL
), "JSON field '%s' is not an integer.", strna(name
));
107 t
= json_variant_integer(variant
);
109 return json_log(variant
, flags
, SYNTHETIC_ERRNO(EINVAL
), "JSON field '%s' is out of bounds for an interface index.", strna(name
));
115 static int json_dispatch_family(const char *name
, JsonVariant
*variant
, JsonDispatchFlags flags
, void *userdata
) {
116 int *family
= userdata
;
122 if (!json_variant_is_integer(variant
))
123 return json_log(variant
, flags
, SYNTHETIC_ERRNO(EINVAL
), "JSON field '%s' is not an integer.", strna(name
));
125 t
= json_variant_integer(variant
);
126 if (t
< 0 || t
> INT_MAX
)
127 return json_log(variant
, flags
, SYNTHETIC_ERRNO(EINVAL
), "JSON field '%s' is not a valid family.", strna(name
));
133 typedef struct ResolveHostnameReply
{
134 JsonVariant
*addresses
;
137 } ResolveHostnameReply
;
139 static void resolve_hostname_reply_destroy(ResolveHostnameReply
*p
) {
142 json_variant_unref(p
->addresses
);
146 static const JsonDispatch resolve_hostname_reply_dispatch_table
[] = {
147 { "addresses", JSON_VARIANT_ARRAY
, json_dispatch_variant
, offsetof(ResolveHostnameReply
, addresses
), JSON_MANDATORY
},
148 { "name", JSON_VARIANT_STRING
, json_dispatch_string
, offsetof(ResolveHostnameReply
, name
), 0 },
149 { "flags", JSON_VARIANT_UNSIGNED
, json_dispatch_uint64
, offsetof(ResolveHostnameReply
, flags
), 0 },
153 typedef struct AddressParameters
{
156 union in_addr_union address
;
160 static int json_dispatch_address(const char *name
, JsonVariant
*variant
, JsonDispatchFlags flags
, void *userdata
) {
161 AddressParameters
*p
= userdata
;
162 union in_addr_union buf
= {};
169 if (!json_variant_is_array(variant
))
170 return json_log(variant
, flags
, SYNTHETIC_ERRNO(EINVAL
), "JSON field '%s' is not an array.", strna(name
));
172 n
= json_variant_elements(variant
);
173 if (!IN_SET(n
, 4, 16))
174 return json_log(variant
, flags
, SYNTHETIC_ERRNO(EINVAL
), "JSON field '%s' is array of unexpected size.", strna(name
));
176 JSON_VARIANT_ARRAY_FOREACH(i
, variant
) {
179 if (!json_variant_is_integer(i
))
180 return json_log(variant
, flags
, SYNTHETIC_ERRNO(EINVAL
), "Element %zu of JSON field '%s' is not an integer.", k
, strna(name
));
182 b
= json_variant_integer(i
);
183 if (b
< 0 || b
> 0xff)
184 return json_log(variant
, flags
, SYNTHETIC_ERRNO(EINVAL
),
185 "Element %zu of JSON field '%s' is out of range 0%s255.",
186 k
, strna(name
), special_glyph(SPECIAL_GLYPH_ELLIPSIS
));
188 buf
.bytes
[k
++] = (uint8_t) b
;
197 static const JsonDispatch address_parameters_dispatch_table
[] = {
198 { "ifindex", JSON_VARIANT_INTEGER
, json_dispatch_ifindex
, offsetof(AddressParameters
, ifindex
), 0 },
199 { "family", JSON_VARIANT_INTEGER
, json_dispatch_family
, offsetof(AddressParameters
, family
), JSON_MANDATORY
},
200 { "address", JSON_VARIANT_ARRAY
, json_dispatch_address
, 0, JSON_MANDATORY
},
204 static uint64_t query_flag(
210 r
= getenv_bool_secure(name
);
212 return r
== value
? flag
: 0;
214 log_debug_errno(r
, "Failed to parse $%s, ignoring.", name
);
218 static uint64_t query_flags(void) {
219 /* Allow callers to turn off validation, synthetization, caching, etc., when we resolve via
221 return query_flag("SYSTEMD_NSS_RESOLVE_VALIDATE", 0, SD_RESOLVED_NO_VALIDATE
) |
222 query_flag("SYSTEMD_NSS_RESOLVE_SYNTHESIZE", 0, SD_RESOLVED_NO_SYNTHESIZE
) |
223 query_flag("SYSTEMD_NSS_RESOLVE_CACHE", 0, SD_RESOLVED_NO_CACHE
) |
224 query_flag("SYSTEMD_NSS_RESOLVE_ZONE", 0, SD_RESOLVED_NO_ZONE
) |
225 query_flag("SYSTEMD_NSS_RESOLVE_TRUST_ANCHOR", 0, SD_RESOLVED_NO_TRUST_ANCHOR
) |
226 query_flag("SYSTEMD_NSS_RESOLVE_NETWORK", 0, SD_RESOLVED_NO_NETWORK
);
229 enum nss_status
_nss_resolve_gethostbyname4_r(
231 struct gaih_addrtuple
**pat
,
232 char *buffer
, size_t buflen
,
233 int *errnop
, int *h_errnop
,
236 _cleanup_(varlink_unrefp
) Varlink
*link
= NULL
;
237 _cleanup_(json_variant_unrefp
) JsonVariant
*cparams
= NULL
;
238 _cleanup_(resolve_hostname_reply_destroy
) ResolveHostnameReply p
= {};
239 JsonVariant
*rparams
, *entry
;
243 NSS_ENTRYPOINT_BEGIN
;
251 r
= connect_to_resolved(&link
);
255 r
= json_build(&cparams
, JSON_BUILD_OBJECT(
256 JSON_BUILD_PAIR("name", JSON_BUILD_STRING(name
)),
257 JSON_BUILD_PAIR("flags", JSON_BUILD_UNSIGNED(query_flags()))));
261 /* Return NSS_STATUS_UNAVAIL when communication with systemd-resolved fails, allowing falling
262 * back to other nss modules. Treat all other error conditions as NOTFOUND. This includes
263 * DNSSEC errors and suchlike. (We don't use UNAVAIL in this case so that the nsswitch.conf
264 * configuration can distinguish such executed but negative replies from complete failure to
265 * talk to resolved). */
266 const char *error_id
;
267 r
= varlink_call(link
, "io.systemd.Resolve.ResolveHostname", cparams
, &rparams
, &error_id
, NULL
);
270 if (!isempty(error_id
)) {
271 if (error_shall_try_again(error_id
))
273 if (error_shall_fallback(error_id
))
278 r
= json_dispatch(rparams
, resolve_hostname_reply_dispatch_table
, NULL
, json_dispatch_flags
, &p
);
281 if (json_variant_is_blank_object(p
.addresses
))
284 size_t n_addresses
= 0;
285 JSON_VARIANT_ARRAY_FOREACH(entry
, p
.addresses
) {
286 AddressParameters q
= {};
288 r
= json_dispatch(entry
, address_parameters_dispatch_table
, NULL
, json_dispatch_flags
, &q
);
292 if (!IN_SET(q
.family
, AF_INET
, AF_INET6
))
295 if (q
.address_size
!= FAMILY_ADDRESS_SIZE(q
.family
)) {
303 const char *canonical
= p
.name
?: name
;
304 size_t l
= strlen(canonical
);
305 size_t idx
, ms
= ALIGN(l
+1) + ALIGN(sizeof(struct gaih_addrtuple
)) * n_addresses
;
310 *h_errnop
= NETDB_INTERNAL
;
311 return NSS_STATUS_TRYAGAIN
;
314 /* First, append name */
315 char *r_name
= buffer
;
316 memcpy(r_name
, canonical
, l
+ 1);
319 /* Second, append addresses */
320 struct gaih_addrtuple
*r_tuple
= NULL
,
321 *r_tuple_first
= (struct gaih_addrtuple
*) (buffer
+ idx
);
323 JSON_VARIANT_ARRAY_FOREACH(entry
, p
.addresses
) {
324 AddressParameters q
= {};
326 r
= json_dispatch(entry
, address_parameters_dispatch_table
, NULL
, json_dispatch_flags
, &q
);
330 if (!IN_SET(q
.family
, AF_INET
, AF_INET6
))
333 r_tuple
= (struct gaih_addrtuple
*) (buffer
+ idx
);
334 r_tuple
->next
= (struct gaih_addrtuple
*) ((char*) r_tuple
+ ALIGN(sizeof(struct gaih_addrtuple
)));
335 r_tuple
->name
= r_name
;
336 r_tuple
->family
= q
.family
;
337 r_tuple
->scopeid
= ifindex_to_scopeid(q
.family
, &q
.address
, q
.ifindex
);
338 memcpy(r_tuple
->addr
, &q
.address
, q
.address_size
);
340 idx
+= ALIGN(sizeof(struct gaih_addrtuple
));
343 assert(r_tuple
); /* We had at least one address, so r_tuple must be set */
344 r_tuple
->next
= NULL
; /* Override last next pointer */
349 **pat
= *r_tuple_first
;
351 *pat
= r_tuple_first
;
356 /* Explicitly reset both *h_errnop and h_errno to work around
357 * https://bugzilla.redhat.com/show_bug.cgi?id=1125975 */
358 *h_errnop
= NETDB_SUCCESS
;
361 return NSS_STATUS_SUCCESS
;
366 *h_errnop
= NO_RECOVERY
;
367 return NSS_STATUS_UNAVAIL
;
370 *h_errnop
= HOST_NOT_FOUND
;
371 return NSS_STATUS_NOTFOUND
;
376 *h_errnop
= TRY_AGAIN
;
377 return NSS_STATUS_TRYAGAIN
;
380 enum nss_status
_nss_resolve_gethostbyname3_r(
383 struct hostent
*result
,
384 char *buffer
, size_t buflen
,
385 int *errnop
, int *h_errnop
,
389 _cleanup_(varlink_unrefp
) Varlink
*link
= NULL
;
390 _cleanup_(json_variant_unrefp
) JsonVariant
*cparams
= NULL
;
391 _cleanup_(resolve_hostname_reply_destroy
) ResolveHostnameReply p
= {};
392 JsonVariant
*rparams
, *entry
;
396 NSS_ENTRYPOINT_BEGIN
;
407 if (!IN_SET(af
, AF_INET
, AF_INET6
)) {
412 r
= connect_to_resolved(&link
);
416 r
= json_build(&cparams
, JSON_BUILD_OBJECT(JSON_BUILD_PAIR("name", JSON_BUILD_STRING(name
)),
417 JSON_BUILD_PAIR("family", JSON_BUILD_INTEGER(af
)),
418 JSON_BUILD_PAIR("flags", JSON_BUILD_UNSIGNED(query_flags()))));
422 const char *error_id
;
423 r
= varlink_call(link
, "io.systemd.Resolve.ResolveHostname", cparams
, &rparams
, &error_id
, NULL
);
426 if (!isempty(error_id
)) {
427 if (error_shall_try_again(error_id
))
429 if (error_shall_fallback(error_id
))
434 r
= json_dispatch(rparams
, resolve_hostname_reply_dispatch_table
, NULL
, json_dispatch_flags
, &p
);
437 if (json_variant_is_blank_object(p
.addresses
))
440 size_t n_addresses
= 0;
441 JSON_VARIANT_ARRAY_FOREACH(entry
, p
.addresses
) {
442 AddressParameters q
= {};
444 r
= json_dispatch(entry
, address_parameters_dispatch_table
, NULL
, json_dispatch_flags
, &q
);
448 if (!IN_SET(q
.family
, AF_INET
, AF_INET6
))
451 if (q
.address_size
!= FAMILY_ADDRESS_SIZE(q
.family
)) {
459 const char *canonical
= p
.name
?: name
;
461 size_t alen
= FAMILY_ADDRESS_SIZE(af
);
462 size_t l
= strlen(canonical
);
464 size_t idx
, ms
= ALIGN(l
+ 1) + n_addresses
* ALIGN(alen
) + (n_addresses
+ 2) * sizeof(char*);
469 *h_errnop
= NETDB_INTERNAL
;
470 return NSS_STATUS_TRYAGAIN
;
473 /* First, append name */
474 char *r_name
= buffer
;
475 memcpy(r_name
, canonical
, l
+1);
478 /* Second, create empty aliases array */
479 char *r_aliases
= buffer
+ idx
;
480 ((char**) r_aliases
)[0] = NULL
;
481 idx
+= sizeof(char*);
483 /* Third, append addresses */
484 char *r_addr
= buffer
+ idx
;
487 JSON_VARIANT_ARRAY_FOREACH(entry
, p
.addresses
) {
488 AddressParameters q
= {};
490 r
= json_dispatch(entry
, address_parameters_dispatch_table
, NULL
, json_dispatch_flags
, &q
);
497 if (q
.address_size
!= alen
) {
502 memcpy(r_addr
+ i
*ALIGN(alen
), &q
.address
, alen
);
506 assert(i
== n_addresses
);
507 idx
+= n_addresses
* ALIGN(alen
);
509 /* Fourth, append address pointer array */
510 char *r_addr_list
= buffer
+ idx
;
511 for (i
= 0; i
< n_addresses
; i
++)
512 ((char**) r_addr_list
)[i
] = r_addr
+ i
*ALIGN(alen
);
514 ((char**) r_addr_list
)[i
] = NULL
;
515 idx
+= (n_addresses
+ 1) * sizeof(char*);
519 result
->h_name
= r_name
;
520 result
->h_aliases
= (char**) r_aliases
;
521 result
->h_addrtype
= af
;
522 result
->h_length
= alen
;
523 result
->h_addr_list
= (char**) r_addr_list
;
531 /* Explicitly reset both *h_errnop and h_errno to work around
532 * https://bugzilla.redhat.com/show_bug.cgi?id=1125975 */
533 *h_errnop
= NETDB_SUCCESS
;
536 return NSS_STATUS_SUCCESS
;
541 *h_errnop
= NO_RECOVERY
;
542 return NSS_STATUS_UNAVAIL
;
545 *h_errnop
= HOST_NOT_FOUND
;
546 return NSS_STATUS_NOTFOUND
;
551 *h_errnop
= TRY_AGAIN
;
552 return NSS_STATUS_TRYAGAIN
;
555 typedef struct ResolveAddressReply
{
558 } ResolveAddressReply
;
560 static void resolve_address_reply_destroy(ResolveAddressReply
*p
) {
563 json_variant_unref(p
->names
);
566 static const JsonDispatch resolve_address_reply_dispatch_table
[] = {
567 { "names", JSON_VARIANT_ARRAY
, json_dispatch_variant
, offsetof(ResolveAddressReply
, names
), JSON_MANDATORY
},
568 { "flags", JSON_VARIANT_UNSIGNED
, json_dispatch_uint64
, offsetof(ResolveAddressReply
, flags
), 0 },
572 typedef struct NameParameters
{
577 static void name_parameters_destroy(NameParameters
*p
) {
583 static const JsonDispatch name_parameters_dispatch_table
[] = {
584 { "ifindex", JSON_VARIANT_INTEGER
, json_dispatch_ifindex
, offsetof(NameParameters
, ifindex
), 0 },
585 { "name", JSON_VARIANT_STRING
, json_dispatch_string
, offsetof(NameParameters
, name
), JSON_MANDATORY
},
589 enum nss_status
_nss_resolve_gethostbyaddr2_r(
590 const void* addr
, socklen_t len
,
592 struct hostent
*result
,
593 char *buffer
, size_t buflen
,
594 int *errnop
, int *h_errnop
,
597 _cleanup_(varlink_unrefp
) Varlink
*link
= NULL
;
598 _cleanup_(json_variant_unrefp
) JsonVariant
*cparams
= NULL
;
599 _cleanup_(resolve_address_reply_destroy
) ResolveAddressReply p
= {};
600 JsonVariant
*rparams
, *entry
;
604 NSS_ENTRYPOINT_BEGIN
;
612 if (!IN_SET(af
, AF_INET
, AF_INET6
)) {
614 *errnop
= EAFNOSUPPORT
;
616 return NSS_STATUS_UNAVAIL
;
619 if (len
!= FAMILY_ADDRESS_SIZE(af
)) {
624 r
= connect_to_resolved(&link
);
628 r
= json_build(&cparams
, JSON_BUILD_OBJECT(JSON_BUILD_PAIR("address", JSON_BUILD_BYTE_ARRAY(addr
, len
)),
629 JSON_BUILD_PAIR("family", JSON_BUILD_INTEGER(af
)),
630 JSON_BUILD_PAIR("flags", JSON_BUILD_UNSIGNED(query_flags()))));
634 const char* error_id
;
635 r
= varlink_call(link
, "io.systemd.Resolve.ResolveAddress", cparams
, &rparams
, &error_id
, NULL
);
638 if (!isempty(error_id
)) {
639 if (error_shall_try_again(error_id
))
641 if (error_shall_fallback(error_id
))
646 r
= json_dispatch(rparams
, resolve_address_reply_dispatch_table
, NULL
, json_dispatch_flags
, &p
);
649 if (json_variant_is_blank_object(p
.names
))
654 JSON_VARIANT_ARRAY_FOREACH(entry
, p
.names
) {
655 _cleanup_(name_parameters_destroy
) NameParameters q
= {};
657 r
= json_dispatch(entry
, name_parameters_dispatch_table
, NULL
, json_dispatch_flags
, &q
);
661 ms
+= ALIGN(strlen(q
.name
) + 1);
664 size_t n_names
= json_variant_elements(p
.names
);
665 ms
+= ALIGN(len
) + /* the address */
666 2 * sizeof(char*) + /* pointer to the address, plus trailing NULL */
667 n_names
* sizeof(char*); /* pointers to aliases, plus trailing NULL */
672 *h_errnop
= NETDB_INTERNAL
;
673 return NSS_STATUS_TRYAGAIN
;
676 /* First, place address */
677 char *r_addr
= buffer
;
678 memcpy(r_addr
, addr
, len
);
681 /* Second, place address list */
682 char *r_addr_list
= buffer
+ idx
;
683 ((char**) r_addr_list
)[0] = r_addr
;
684 ((char**) r_addr_list
)[1] = NULL
;
685 idx
+= sizeof(char*) * 2;
687 /* Third, reserve space for the aliases array, plus trailing NULL */
688 char *r_aliases
= buffer
+ idx
;
689 idx
+= sizeof(char*) * n_names
;
691 /* Fourth, place aliases */
692 char *r_name
= buffer
+ idx
;
695 JSON_VARIANT_ARRAY_FOREACH(entry
, p
.names
) {
696 _cleanup_(name_parameters_destroy
) NameParameters q
= {};
698 r
= json_dispatch(entry
, name_parameters_dispatch_table
, NULL
, json_dispatch_flags
, &q
);
702 size_t l
= strlen(q
.name
);
703 char *z
= buffer
+ idx
;
704 memcpy(z
, q
.name
, l
+ 1);
707 ((char**) r_aliases
)[i
- 1] = z
;
712 ((char**) r_aliases
)[n_names
- 1] = NULL
;
716 result
->h_name
= r_name
;
717 result
->h_aliases
= (char**) r_aliases
;
718 result
->h_addrtype
= af
;
719 result
->h_length
= len
;
720 result
->h_addr_list
= (char**) r_addr_list
;
725 /* Explicitly reset both *h_errnop and h_errno to work around
726 * https://bugzilla.redhat.com/show_bug.cgi?id=1125975 */
727 *h_errnop
= NETDB_SUCCESS
;
730 return NSS_STATUS_SUCCESS
;
735 *h_errnop
= NO_RECOVERY
;
736 return NSS_STATUS_UNAVAIL
;
739 *h_errnop
= HOST_NOT_FOUND
;
740 return NSS_STATUS_NOTFOUND
;
745 *h_errnop
= TRY_AGAIN
;
746 return NSS_STATUS_TRYAGAIN
;
749 NSS_GETHOSTBYNAME_FALLBACKS(resolve
);
750 NSS_GETHOSTBYADDR_FALLBACKS(resolve
);