json: add json_dispatch_const_user_group_name()

This is the same as json_dispatch_user_group_name() but fills in the
string as "const char*" to the JSON field. Or in other words, it's what
sd_json_dispatch_const_string() is to sd_json_dispatch_string().

Note this drops the SD_JSON_STRICT flags from various dispatch tables
for these fields, and replaces this by SD_JSON_RELAX, i.e. the opposite
behaviour. As #34558 correctly suggests we should validate user names
in lookup functions using the lax rules, rather than the strict ones,
since clients not knowing the rules might ask us for arbitrary
resolution.

(SD_JSON_RELAX internally translates to valid_user_group_name() with the
VALID_USER_RELAX flag).

See: #34558

7 files changed, 70 insertions, 48 deletions

diff --git a/src/core/core-varlink.c b/src/core/core-varlink.c
index 8921ecd55d..0ecc8e23f1 100644
--- a/src/core/core-varlink.c
+++ b/src/core/core-varlink.c
@@ -347,9 +347,9 @@ static int vl_method_subscribe_managed_oom_cgroups(
 static int vl_method_get_user_record(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata) {
 
         static const sd_json_dispatch_field dispatch_table[] = {
-                { "uid",      SD_JSON_VARIANT_UNSIGNED, sd_json_dispatch_uid_gid,      offsetof(LookupParameters, uid),       0              },
-                { "userName", SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string, offsetof(LookupParameters, user_name), SD_JSON_STRICT },
-                { "service",  SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string, offsetof(LookupParameters, service),   0              },
+                { "uid",      SD_JSON_VARIANT_UNSIGNED, sd_json_dispatch_uid_gid,            offsetof(LookupParameters, uid),       0             },
+                { "userName", SD_JSON_VARIANT_STRING,   json_dispatch_const_user_group_name, offsetof(LookupParameters, user_name), SD_JSON_RELAX },
+                { "service",  SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string,       offsetof(LookupParameters, service),   0             },
                 {}
         };
 
@@ -453,9 +453,9 @@ static bool group_match_lookup_parameters(LookupParameters *p, const char *name,
 static int vl_method_get_group_record(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata) {
 
         static const sd_json_dispatch_field dispatch_table[] = {
-                { "gid",       SD_JSON_VARIANT_UNSIGNED, sd_json_dispatch_uid_gid,      offsetof(LookupParameters, gid),        0              },
-                { "groupName", SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string, offsetof(LookupParameters, group_name), SD_JSON_STRICT },
-                { "service",   SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string, offsetof(LookupParameters, service),    0              },
+                { "gid",       SD_JSON_VARIANT_UNSIGNED, sd_json_dispatch_uid_gid,            offsetof(LookupParameters, gid),        0             },
+                { "groupName", SD_JSON_VARIANT_STRING,   json_dispatch_const_user_group_name, offsetof(LookupParameters, group_name), SD_JSON_RELAX },
+                { "service",   SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string,       offsetof(LookupParameters, service),    0             },
                 {}
         };
 
@@ -536,9 +536,9 @@ static int vl_method_get_group_record(sd_varlink *link, sd_json_variant *paramet
 static int vl_method_get_memberships(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata) {
 
         static const sd_json_dispatch_field dispatch_table[] = {
-                { "userName",  SD_JSON_VARIANT_STRING, sd_json_dispatch_const_string, offsetof(LookupParameters, user_name),  SD_JSON_STRICT },
-                { "groupName", SD_JSON_VARIANT_STRING, sd_json_dispatch_const_string, offsetof(LookupParameters, group_name), SD_JSON_STRICT },
-                { "service",   SD_JSON_VARIANT_STRING, sd_json_dispatch_const_string, offsetof(LookupParameters, service),    0              },
+                { "userName",  SD_JSON_VARIANT_STRING, json_dispatch_const_user_group_name, offsetof(LookupParameters, user_name),  SD_JSON_RELAX },
+                { "groupName", SD_JSON_VARIANT_STRING, json_dispatch_const_user_group_name, offsetof(LookupParameters, group_name), SD_JSON_RELAX },
+                { "service",   SD_JSON_VARIANT_STRING, sd_json_dispatch_const_string,       offsetof(LookupParameters, service),    0             },
                 {}
         };
 
diff --git a/src/home/homed-varlink.c b/src/home/homed-varlink.c
index 54559d3a08..f6dd27594f 100644
--- a/src/home/homed-varlink.c
+++ b/src/home/homed-varlink.c
@@ -1,12 +1,13 @@
 /* SPDX-License-Identifier: LGPL-2.1-or-later */
 
+#include "format-util.h"
 #include "group-record.h"
 #include "homed-varlink.h"
+#include "json-util.h"
 #include "strv.h"
 #include "user-record-util.h"
 #include "user-record.h"
 #include "user-util.h"
-#include "format-util.h"
 
 typedef struct LookupParameters {
         const char *user_name;
@@ -73,9 +74,9 @@ static bool home_user_match_lookup_parameters(LookupParameters *p, Home *h) {
 int vl_method_get_user_record(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata) {
 
         static const sd_json_dispatch_field dispatch_table[] = {
-                { "uid",      SD_JSON_VARIANT_UNSIGNED, sd_json_dispatch_uid_gid,      offsetof(LookupParameters, uid),       0              },
-                { "userName", SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string, offsetof(LookupParameters, user_name), SD_JSON_STRICT },
-                { "service",  SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string, offsetof(LookupParameters, service),   0              },
+                { "uid",      SD_JSON_VARIANT_UNSIGNED, sd_json_dispatch_uid_gid,            offsetof(LookupParameters, uid),       0             },
+                { "userName", SD_JSON_VARIANT_STRING,   json_dispatch_const_user_group_name, offsetof(LookupParameters, user_name), SD_JSON_RELAX },
+                { "service",  SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string,       offsetof(LookupParameters, service),   0             },
                 {}
         };
 
@@ -186,9 +187,9 @@ static bool home_group_match_lookup_parameters(LookupParameters *p, Home *h) {
 int vl_method_get_group_record(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata) {
 
         static const sd_json_dispatch_field dispatch_table[] = {
-                { "gid",       SD_JSON_VARIANT_UNSIGNED, sd_json_dispatch_uid_gid,      offsetof(LookupParameters, gid),        0              },
-                { "groupName", SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string, offsetof(LookupParameters, group_name), SD_JSON_STRICT },
-                { "service",   SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string, offsetof(LookupParameters, service),    0              },
+                { "gid",       SD_JSON_VARIANT_UNSIGNED, sd_json_dispatch_uid_gid,            offsetof(LookupParameters, gid),        0             },
+                { "groupName", SD_JSON_VARIANT_STRING,   json_dispatch_const_user_group_name, offsetof(LookupParameters, group_name), SD_JSON_RELAX },
+                { "service",   SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string,       offsetof(LookupParameters, service),    0             },
                 {}
         };
 
@@ -255,9 +256,9 @@ int vl_method_get_group_record(sd_varlink *link, sd_json_variant *parameters, sd
 int vl_method_get_memberships(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata) {
 
         static const sd_json_dispatch_field dispatch_table[] = {
-                { "userName",  SD_JSON_VARIANT_STRING, sd_json_dispatch_const_string, offsetof(LookupParameters, user_name),  SD_JSON_STRICT },
-                { "groupName", SD_JSON_VARIANT_STRING, sd_json_dispatch_const_string, offsetof(LookupParameters, group_name), SD_JSON_STRICT },
-                { "service",   SD_JSON_VARIANT_STRING, sd_json_dispatch_const_string, offsetof(LookupParameters, service),    0              },
+                { "userName",  SD_JSON_VARIANT_STRING, json_dispatch_const_user_group_name, offsetof(LookupParameters, user_name),  SD_JSON_RELAX },
+                { "groupName", SD_JSON_VARIANT_STRING, json_dispatch_const_user_group_name, offsetof(LookupParameters, group_name), SD_JSON_RELAX },
+                { "service",   SD_JSON_VARIANT_STRING, sd_json_dispatch_const_string,       offsetof(LookupParameters, service),    0             },
                 {}
         };
 
diff --git a/src/libsystemd/sd-json/json-util.c b/src/libsystemd/sd-json/json-util.c
index e039ed5197..fb8d2f46c3 100644
--- a/src/libsystemd/sd-json/json-util.c
+++ b/src/libsystemd/sd-json/json-util.c
@@ -69,7 +69,7 @@ int json_dispatch_byte_array_iovec(const char *name, sd_json_variant *variant, s
 }
 
 int json_dispatch_user_group_name(const char *name, sd_json_variant *variant, sd_json_dispatch_flags_t flags, void *userdata) {
-        char **s = userdata;
+        char **s = ASSERT_PTR(userdata);
         const char *n;
         int r;
 
@@ -92,6 +92,25 @@ int json_dispatch_user_group_name(const char *name, sd_json_variant *variant, sd
         return 0;
 }
 
+int json_dispatch_const_user_group_name(const char *name, sd_json_variant *variant, sd_json_dispatch_flags_t flags, void *userdata) {
+        const char **s = ASSERT_PTR(userdata), *n;
+
+        if (sd_json_variant_is_null(variant)) {
+                *s = NULL;
+                return 0;
+        }
+
+        if (!sd_json_variant_is_string(variant))
+                return json_log(variant, flags, SYNTHETIC_ERRNO(EINVAL), "JSON field '%s' is not a string.", strna(name));
+
+        n = sd_json_variant_string(variant);
+        if (!valid_user_group_name(n, FLAGS_SET(flags, SD_JSON_RELAX) ? VALID_USER_RELAX : 0))
+                return json_log(variant, flags, SYNTHETIC_ERRNO(EINVAL), "JSON field '%s' is not a valid user/group name.", strna(name));
+
+        *s = n;
+        return 0;
+}
+
 int json_dispatch_in_addr(const char *name, sd_json_variant *variant, sd_json_dispatch_flags_t flags, void *userdata) {
         struct in_addr *address = ASSERT_PTR(userdata);
         _cleanup_(iovec_done) struct iovec iov = {};
diff --git a/src/libsystemd/sd-json/json-util.h b/src/libsystemd/sd-json/json-util.h
index 3823eb32dd..3821e451d4 100644
--- a/src/libsystemd/sd-json/json-util.h
+++ b/src/libsystemd/sd-json/json-util.h
@@ -109,6 +109,7 @@ int json_log_internal(sd_json_variant *variant, int level, int error, const char
 int json_dispatch_unbase64_iovec(const char *name, sd_json_variant *variant, sd_json_dispatch_flags_t flags, void *userdata);
 int json_dispatch_byte_array_iovec(const char *name, sd_json_variant *variant, sd_json_dispatch_flags_t flags, void *userdata);
 int json_dispatch_user_group_name(const char *name, sd_json_variant *variant, sd_json_dispatch_flags_t flags, void *userdata);
+int json_dispatch_const_user_group_name(const char *name, sd_json_variant *variant, sd_json_dispatch_flags_t flags, void *userdata);
 int json_dispatch_in_addr(const char *name, sd_json_variant *variant, sd_json_dispatch_flags_t flags, void *userdata);
 int json_dispatch_path(const char *name, sd_json_variant *variant, sd_json_dispatch_flags_t flags, void *userdata);
 
diff --git a/src/machine/machined-varlink.c b/src/machine/machined-varlink.c
index a09c51b470..942b0a96b3 100644
--- a/src/machine/machined-varlink.c
+++ b/src/machine/machined-varlink.c
@@ -146,9 +146,9 @@ static int user_lookup_name(Manager *m, const char *name, uid_t *ret_uid, char *
 static int vl_method_get_user_record(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata) {
 
         static const sd_json_dispatch_field dispatch_table[] = {
-                { "uid",      SD_JSON_VARIANT_UNSIGNED, sd_json_dispatch_uid_gid,      offsetof(LookupParameters, uid),       0              },
-                { "userName", SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string, offsetof(LookupParameters, user_name), SD_JSON_STRICT },
-                { "service",  SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string, offsetof(LookupParameters, service),   0              },
+                { "uid",      SD_JSON_VARIANT_UNSIGNED, sd_json_dispatch_uid_gid,            offsetof(LookupParameters, uid),       0             },
+                { "userName", SD_JSON_VARIANT_STRING,   json_dispatch_const_user_group_name, offsetof(LookupParameters, user_name), SD_JSON_RELAX },
+                { "service",  SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string,       offsetof(LookupParameters, service),   0             },
                 {}
         };
 
@@ -312,9 +312,9 @@ static int group_lookup_name(Manager *m, const char *name, gid_t *ret_gid, char
 static int vl_method_get_group_record(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata) {
 
         static const sd_json_dispatch_field dispatch_table[] = {
-                { "gid",       SD_JSON_VARIANT_UNSIGNED, sd_json_dispatch_uid_gid,      offsetof(LookupParameters, gid),        0              },
-                { "groupName", SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string, offsetof(LookupParameters, group_name), SD_JSON_STRICT },
-                { "service",   SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string, offsetof(LookupParameters, service),    0              },
+                { "gid",       SD_JSON_VARIANT_UNSIGNED, sd_json_dispatch_uid_gid,            offsetof(LookupParameters, gid),        0             },
+                { "groupName", SD_JSON_VARIANT_STRING,   json_dispatch_const_user_group_name, offsetof(LookupParameters, group_name), SD_JSON_RELAX },
+                { "service",   SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string,       offsetof(LookupParameters, service),    0             },
                 {}
         };
 
@@ -364,9 +364,9 @@ static int vl_method_get_group_record(sd_varlink *link, sd_json_variant *paramet
 static int vl_method_get_memberships(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata) {
 
         static const sd_json_dispatch_field dispatch_table[] = {
-                { "userName",  SD_JSON_VARIANT_STRING, sd_json_dispatch_const_string, offsetof(LookupParameters, user_name),  SD_JSON_STRICT },
-                { "groupName", SD_JSON_VARIANT_STRING, sd_json_dispatch_const_string, offsetof(LookupParameters, group_name), SD_JSON_STRICT },
-                { "service",   SD_JSON_VARIANT_STRING, sd_json_dispatch_const_string, offsetof(LookupParameters, service),    0              },
+                { "userName",  SD_JSON_VARIANT_STRING, json_dispatch_const_user_group_name, offsetof(LookupParameters, user_name),  SD_JSON_RELAX },
+                { "groupName", SD_JSON_VARIANT_STRING, json_dispatch_const_user_group_name, offsetof(LookupParameters, group_name), SD_JSON_RELAX },
+                { "service",   SD_JSON_VARIANT_STRING, sd_json_dispatch_const_string,       offsetof(LookupParameters, service),    0             },
                 {}
         };
 
diff --git a/src/nsresourced/nsresourcework.c b/src/nsresourced/nsresourcework.c
index 892eaf3b57..e8929ad6b3 100644
--- a/src/nsresourced/nsresourcework.c
+++ b/src/nsresourced/nsresourcework.c
@@ -99,9 +99,9 @@ static int build_user_json(UserNamespaceInfo *userns_info, uid_t offset, sd_json
 static int vl_method_get_user_record(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata) {
 
         static const sd_json_dispatch_field dispatch_table[] = {
-                { "uid",      SD_JSON_VARIANT_UNSIGNED, sd_json_dispatch_uid_gid,      offsetof(LookupParameters, uid),       0 },
-                { "userName", SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string, offsetof(LookupParameters, user_name), 0 },
-                { "service",  SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string, offsetof(LookupParameters, service),   0 },
+                { "uid",      SD_JSON_VARIANT_UNSIGNED, sd_json_dispatch_uid_gid,            offsetof(LookupParameters, uid),       0             },
+                { "userName", SD_JSON_VARIANT_STRING,   json_dispatch_const_user_group_name, offsetof(LookupParameters, user_name), SD_JSON_RELAX },
+                { "service",  SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string,       offsetof(LookupParameters, service),   0             },
                 {}
         };
 
@@ -226,9 +226,9 @@ static int build_group_json(UserNamespaceInfo *userns_info, gid_t offset, sd_jso
 static int vl_method_get_group_record(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata) {
 
         static const sd_json_dispatch_field dispatch_table[] = {
-                { "gid",       SD_JSON_VARIANT_UNSIGNED, sd_json_dispatch_uid_gid,      offsetof(LookupParameters, gid),        0 },
-                { "groupName", SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string, offsetof(LookupParameters, group_name), 0 },
-                { "service",   SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string, offsetof(LookupParameters, service),    0 },
+                { "gid",       SD_JSON_VARIANT_UNSIGNED, sd_json_dispatch_uid_gid,            offsetof(LookupParameters, gid),        0             },
+                { "groupName", SD_JSON_VARIANT_STRING,   json_dispatch_const_user_group_name, offsetof(LookupParameters, group_name), SD_JSON_RELAX },
+                { "service",   SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string,       offsetof(LookupParameters, service),    0             },
                 {}
         };
 
@@ -322,9 +322,9 @@ not_found:
 
 static int vl_method_get_memberships(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata) {
         static const sd_json_dispatch_field dispatch_table[] = {
-                { "userName",  SD_JSON_VARIANT_STRING, sd_json_dispatch_const_string, offsetof(LookupParameters, user_name),  0 },
-                { "groupName", SD_JSON_VARIANT_STRING, sd_json_dispatch_const_string, offsetof(LookupParameters, group_name), 0 },
-                { "service",   SD_JSON_VARIANT_STRING, sd_json_dispatch_const_string, offsetof(LookupParameters, service),    0 },
+                { "userName",  SD_JSON_VARIANT_STRING, json_dispatch_const_user_group_name, offsetof(LookupParameters, user_name),  SD_JSON_RELAX },
+                { "groupName", SD_JSON_VARIANT_STRING, json_dispatch_const_user_group_name, offsetof(LookupParameters, group_name), SD_JSON_RELAX },
+                { "service",   SD_JSON_VARIANT_STRING, sd_json_dispatch_const_string,       offsetof(LookupParameters, service),    0             },
                 {}
         };
 
diff --git a/src/userdb/userwork.c b/src/userdb/userwork.c
index 5781d8c788..b7a2bf798c 100644
--- a/src/userdb/userwork.c
+++ b/src/userdb/userwork.c
@@ -10,12 +10,13 @@
 #include "fd-util.h"
 #include "group-record.h"
 #include "io-util.h"
+#include "json-util.h"
 #include "main-func.h"
 #include "process-util.h"
 #include "strv.h"
 #include "time-util.h"
-#include "user-record-nss.h"
 #include "user-record.h"
+#include "user-record-nss.h"
 #include "user-util.h"
 #include "userdb.h"
 #include "varlink-io.systemd.UserDatabase.h"
@@ -133,9 +134,9 @@ static int userdb_flags_from_service(sd_varlink *link, const char *service, User
 static int vl_method_get_user_record(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata) {
 
         static const sd_json_dispatch_field dispatch_table[] = {
-                { "uid",      SD_JSON_VARIANT_UNSIGNED, sd_json_dispatch_uid_gid,      offsetof(LookupParameters, uid),       0 },
-                { "userName", SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string, offsetof(LookupParameters, user_name), 0 },
-                { "service",  SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string, offsetof(LookupParameters, service),   0 },
+                { "uid",      SD_JSON_VARIANT_UNSIGNED, sd_json_dispatch_uid_gid,            offsetof(LookupParameters, uid),       0             },
+                { "userName", SD_JSON_VARIANT_STRING,   json_dispatch_const_user_group_name, offsetof(LookupParameters, user_name), SD_JSON_RELAX },
+                { "service",  SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string,       offsetof(LookupParameters, service),   0             },
                 {}
         };
 
@@ -270,9 +271,9 @@ static int build_group_json(sd_varlink *link, GroupRecord *gr, sd_json_variant *
 static int vl_method_get_group_record(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata) {
 
         static const sd_json_dispatch_field dispatch_table[] = {
-                { "gid",       SD_JSON_VARIANT_UNSIGNED, sd_json_dispatch_uid_gid,      offsetof(LookupParameters, gid),        0 },
-                { "groupName", SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string, offsetof(LookupParameters, group_name), 0 },
-                { "service",   SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string, offsetof(LookupParameters, service),    0 },
+                { "gid",       SD_JSON_VARIANT_UNSIGNED, sd_json_dispatch_uid_gid,            offsetof(LookupParameters, gid),        0             },
+                { "groupName", SD_JSON_VARIANT_STRING,   json_dispatch_const_user_group_name, offsetof(LookupParameters, group_name), SD_JSON_RELAX },
+                { "service",   SD_JSON_VARIANT_STRING,   sd_json_dispatch_const_string,       offsetof(LookupParameters, service),    0             },
                 {}
         };
 
@@ -355,9 +356,9 @@ static int vl_method_get_group_record(sd_varlink *link, sd_json_variant *paramet
 
 static int vl_method_get_memberships(sd_varlink *link, sd_json_variant *parameters, sd_varlink_method_flags_t flags, void *userdata) {
         static const sd_json_dispatch_field dispatch_table[] = {
-                { "userName",  SD_JSON_VARIANT_STRING, sd_json_dispatch_const_string, offsetof(LookupParameters, user_name),  0 },
-                { "groupName", SD_JSON_VARIANT_STRING, sd_json_dispatch_const_string, offsetof(LookupParameters, group_name), 0 },
-                { "service",   SD_JSON_VARIANT_STRING, sd_json_dispatch_const_string, offsetof(LookupParameters, service),    0 },
+                { "userName",  SD_JSON_VARIANT_STRING, json_dispatch_const_user_group_name, offsetof(LookupParameters, user_name),  SD_JSON_RELAX },
+                { "groupName", SD_JSON_VARIANT_STRING, json_dispatch_const_user_group_name, offsetof(LookupParameters, group_name), SD_JSON_RELAX },
+                { "service",   SD_JSON_VARIANT_STRING, sd_json_dispatch_const_string,       offsetof(LookupParameters, service),    0             },
                 {}
         };