src/core/core-varlink.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #include "core-varlink.h"
   4 #include "mkdir.h"
   5 #include "user-util.h"
   6 #include "varlink.h"
   7
   8 typedef struct LookupParameters {
   9         const char *user_name;
  10         const char *group_name;
  11         union {
  12                 uid_t uid;
  13                 gid_t gid;
  14         };
  15         const char *service;
  16 } LookupParameters;
  17
  18 static int build_user_json(const char *user_name, uid_t uid, JsonVariant **ret) {
  19         assert(user_name);
  20         assert(uid_is_valid(uid));
  21         assert(ret);
  22
  23         return json_build(ret, JSON_BUILD_OBJECT(
  24                                    JSON_BUILD_PAIR("record", JSON_BUILD_OBJECT(
  25                                        JSON_BUILD_PAIR("userName", JSON_BUILD_STRING(user_name)),
  26                                        JSON_BUILD_PAIR("uid", JSON_BUILD_UNSIGNED(uid)),
  27                                        JSON_BUILD_PAIR("gid", JSON_BUILD_UNSIGNED(uid)),
  28                                        JSON_BUILD_PAIR("realName", JSON_BUILD_STRING("Dynamic User")),
  29                                        JSON_BUILD_PAIR("homeDirectory", JSON_BUILD_STRING("/")),
  30                                        JSON_BUILD_PAIR("shell", JSON_BUILD_STRING(NOLOGIN)),
  31                                        JSON_BUILD_PAIR("locked", JSON_BUILD_BOOLEAN(true)),
  32                                        JSON_BUILD_PAIR("service", JSON_BUILD_STRING("io.systemd.DynamicUser")),
  33                                        JSON_BUILD_PAIR("disposition", JSON_BUILD_STRING("dynamic"))))));
  34 }
  35
  36 static bool user_match_lookup_parameters(LookupParameters *p, const char *name, uid_t uid) {
  37         assert(p);
  38
  39         if (p->user_name && !streq(name, p->user_name))
  40                 return false;
  41
  42         if (uid_is_valid(p->uid) && uid != p->uid)
  43                 return false;
  44
  45         return true;
  46 }
  47
  48 static int vl_method_get_user_record(Varlink *link, JsonVariant *parameters, VarlinkMethodFlags flags, void *userdata) {
  49
  50         static const JsonDispatch dispatch_table[] = {
  51                 { "uid",      JSON_VARIANT_UNSIGNED, json_dispatch_uid_gid,      offsetof(LookupParameters, uid),       0         },
  52                 { "userName", JSON_VARIANT_STRING,   json_dispatch_const_string, offsetof(LookupParameters, user_name), JSON_SAFE },
  53                 { "service",  JSON_VARIANT_STRING,   json_dispatch_const_string, offsetof(LookupParameters, service),   0         },
  54                 {}
  55         };
  56
  57         _cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
  58         LookupParameters p = {
  59                 .uid = UID_INVALID,
  60         };
  61         _cleanup_free_ char *found_name = NULL;
  62         uid_t found_uid = UID_INVALID, uid;
  63         Manager *m = userdata;
  64         const char *un;
  65         int r;
  66
  67         assert(parameters);
  68         assert(m);
  69
  70         r = json_dispatch(parameters, dispatch_table, NULL, 0, &p);
  71         if (r < 0)
  72                 return r;
  73
  74         if (!streq_ptr(p.service, "io.systemd.DynamicUser"))
  75                 return varlink_error(link, "io.systemd.UserDatabase.BadService", NULL);
  76
  77         if (uid_is_valid(p.uid))
  78                 r = dynamic_user_lookup_uid(m, p.uid, &found_name);
  79         else if (p.user_name)
  80                 r = dynamic_user_lookup_name(m, p.user_name, &found_uid);
  81         else {
  82                 DynamicUser *d;
  83
  84                 HASHMAP_FOREACH(d, m->dynamic_users) {
  85                         r = dynamic_user_current(d, &uid);
  86                         if (r == -EAGAIN) /* not realized yet? */
  87                                 continue;
  88                         if (r < 0)
  89                                 return r;
  90
  91                         if (!user_match_lookup_parameters(&p, d->name, uid))
  92                                 continue;
  93
  94                         if (v) {
  95                                 r = varlink_notify(link, v);
  96                                 if (r < 0)
  97                                         return r;
  98
  99                                 v = json_variant_unref(v);
 100                         }
 101
 102                         r = build_user_json(d->name, uid, &v);
 103                         if (r < 0)
 104                                 return r;
 105                 }
 106
 107                 if (!v)
 108                         return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL);
 109
 110                 return varlink_reply(link, v);
 111         }
 112         if (r == -ESRCH)
 113                 return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL);
 114         if (r < 0)
 115                 return r;
 116
 117         uid = uid_is_valid(found_uid) ? found_uid : p.uid;
 118         un = found_name ?: p.user_name;
 119
 120         if (!user_match_lookup_parameters(&p, un, uid))
 121                 return varlink_error(link, "io.systemd.UserDatabase.ConflictingRecordFound", NULL);
 122
 123         r = build_user_json(un, uid, &v);
 124         if (r < 0)
 125                 return r;
 126
 127         return varlink_reply(link, v);
 128 }
 129
 130 static int build_group_json(const char *group_name, gid_t gid, JsonVariant **ret) {
 131         assert(group_name);
 132         assert(gid_is_valid(gid));
 133         assert(ret);
 134
 135         return json_build(ret, JSON_BUILD_OBJECT(
 136                                    JSON_BUILD_PAIR("record", JSON_BUILD_OBJECT(
 137                                        JSON_BUILD_PAIR("groupName", JSON_BUILD_STRING(group_name)),
 138                                        JSON_BUILD_PAIR("description", JSON_BUILD_STRING("Dynamic Group")),
 139                                        JSON_BUILD_PAIR("gid", JSON_BUILD_UNSIGNED(gid)),
 140                                        JSON_BUILD_PAIR("service", JSON_BUILD_STRING("io.systemd.DynamicUser")),
 141                                        JSON_BUILD_PAIR("disposition", JSON_BUILD_STRING("dynamic"))))));
 142     }
 143
 144 static bool group_match_lookup_parameters(LookupParameters *p, const char *name, gid_t gid) {
 145         assert(p);
 146
 147         if (p->group_name && !streq(name, p->group_name))
 148                 return false;
 149
 150         if (gid_is_valid(p->gid) && gid != p->gid)
 151                 return false;
 152
 153         return true;
 154 }
 155
 156 static int vl_method_get_group_record(Varlink *link, JsonVariant *parameters, VarlinkMethodFlags flags, void *userdata) {
 157
 158         static const JsonDispatch dispatch_table[] = {
 159                 { "gid",       JSON_VARIANT_UNSIGNED, json_dispatch_uid_gid,      offsetof(LookupParameters, gid),        0         },
 160                 { "groupName", JSON_VARIANT_STRING,   json_dispatch_const_string, offsetof(LookupParameters, group_name), JSON_SAFE },
 161                 { "service",   JSON_VARIANT_STRING,   json_dispatch_const_string, offsetof(LookupParameters, service),    0         },
 162                 {}
 163         };
 164
 165         _cleanup_(json_variant_unrefp) JsonVariant *v = NULL;
 166         LookupParameters p = {
 167                 .gid = GID_INVALID,
 168         };
 169         _cleanup_free_ char *found_name = NULL;
 170         uid_t found_gid = GID_INVALID, gid;
 171         Manager *m = userdata;
 172         const char *gn;
 173         int r;
 174
 175         assert(parameters);
 176         assert(m);
 177
 178         r = json_dispatch(parameters, dispatch_table, NULL, 0, &p);
 179         if (r < 0)
 180                 return r;
 181
 182         if (!streq_ptr(p.service, "io.systemd.DynamicUser"))
 183                 return varlink_error(link, "io.systemd.UserDatabase.BadService", NULL);
 184
 185         if (gid_is_valid(p.gid))
 186                 r = dynamic_user_lookup_uid(m, (uid_t) p.gid, &found_name);
 187         else if (p.group_name)
 188                 r = dynamic_user_lookup_name(m, p.group_name, (uid_t*) &found_gid);
 189         else {
 190                 DynamicUser *d;
 191
 192                 HASHMAP_FOREACH(d, m->dynamic_users) {
 193                         uid_t uid;
 194
 195                         r = dynamic_user_current(d, &uid);
 196                         if (r == -EAGAIN)
 197                                 continue;
 198                         if (r < 0)
 199                                 return r;
 200
 201                         if (!group_match_lookup_parameters(&p, d->name, (gid_t) uid))
 202                                 continue;
 203
 204                         if (v) {
 205                                 r = varlink_notify(link, v);
 206                                 if (r < 0)
 207                                         return r;
 208
 209                                 v = json_variant_unref(v);
 210                         }
 211
 212                         r = build_group_json(d->name, (gid_t) uid, &v);
 213                         if (r < 0)
 214                                 return r;
 215                 }
 216
 217                 if (!v)
 218                         return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL);
 219
 220                 return varlink_reply(link, v);
 221         }
 222         if (r == -ESRCH)
 223                 return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL);
 224         if (r < 0)
 225                 return r;
 226
 227         gid = gid_is_valid(found_gid) ? found_gid : p.gid;
 228         gn = found_name ?: p.group_name;
 229
 230         if (!group_match_lookup_parameters(&p, gn, gid))
 231                 return varlink_error(link, "io.systemd.UserDatabase.ConflictingRecordFound", NULL);
 232
 233         r = build_group_json(gn, gid, &v);
 234         if (r < 0)
 235                 return r;
 236
 237         return varlink_reply(link, v);
 238 }
 239
 240 static int vl_method_get_memberships(Varlink *link, JsonVariant *parameters, VarlinkMethodFlags flags, void *userdata) {
 241
 242         static const JsonDispatch dispatch_table[] = {
 243                 { "userName",  JSON_VARIANT_STRING, json_dispatch_const_string, offsetof(LookupParameters, user_name),  JSON_SAFE },
 244                 { "groupName", JSON_VARIANT_STRING, json_dispatch_const_string, offsetof(LookupParameters, group_name), JSON_SAFE },
 245                 { "service",   JSON_VARIANT_STRING, json_dispatch_const_string, offsetof(LookupParameters, service),    0         },
 246                 {}
 247         };
 248
 249         LookupParameters p = {};
 250         int r;
 251
 252         assert(parameters);
 253
 254         r = json_dispatch(parameters, dispatch_table, NULL, 0, &p);
 255         if (r < 0)
 256                 return r;
 257
 258         if (!streq_ptr(p.service, "io.systemd.DynamicUser"))
 259                 return varlink_error(link, "io.systemd.UserDatabase.BadService", NULL);
 260
 261         /* We don't support auxiliary groups with dynamic users. */
 262         return varlink_error(link, "io.systemd.UserDatabase.NoRecordFound", NULL);
 263 }
 264
 265 int manager_varlink_init(Manager *m) {
 266         _cleanup_(varlink_server_unrefp) VarlinkServer *s = NULL;
 267         int r;
 268
 269         assert(m);
 270
 271         if (m->varlink_server)
 272                 return 0;
 273
 274         if (!MANAGER_IS_SYSTEM(m))
 275                 return 0;
 276
 277         r = varlink_server_new(&s, VARLINK_SERVER_ACCOUNT_UID);
 278         if (r < 0)
 279                 return log_error_errno(r, "Failed to allocate varlink server object: %m");
 280
 281         varlink_server_set_userdata(s, m);
 282
 283         r = varlink_server_bind_method_many(
 284                         s,
 285                         "io.systemd.UserDatabase.GetUserRecord",  vl_method_get_user_record,
 286                         "io.systemd.UserDatabase.GetGroupRecord", vl_method_get_group_record,
 287                         "io.systemd.UserDatabase.GetMemberships", vl_method_get_memberships);
 288         if (r < 0)
 289                 return log_error_errno(r, "Failed to register varlink methods: %m");
 290
 291         if (!MANAGER_IS_TEST_RUN(m)) {
 292                 (void) mkdir_p_label("/run/systemd/userdb", 0755);
 293
 294                 r = varlink_server_listen_address(s, "/run/systemd/userdb/io.systemd.DynamicUser", 0666);
 295                 if (r < 0)
 296                         return log_error_errno(r, "Failed to bind to varlink socket: %m");
 297         }
 298
 299         r = varlink_server_attach_event(s, m->event, SD_EVENT_PRIORITY_NORMAL);
 300         if (r < 0)
 301                 return log_error_errno(r, "Failed to attach varlink connection to event loop: %m");
 302
 303         m->varlink_server = TAKE_PTR(s);
 304         return 0;
 305 }
 306
 307 void manager_varlink_done(Manager *m) {
 308         assert(m);
 309
 310         m->varlink_server = varlink_server_unref(m->varlink_server);
 311 }