plugins/session_policy_local.c

   1 /*
   2  *
   3  *  Connection Manager
   4  *
   5  *  Copyright (C) 2012  BMW Car IT GbmH. All rights reserved.
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License version 2 as
   9  *  published by the Free Software Foundation.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  *
  20  */
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include <errno.h>
  27 #include <string.h>
  28 #include <sys/inotify.h>
  29 #include <sys/stat.h>
  30
  31 #include <glib.h>
  32
  33 #include <gdbus.h>
  34
  35 #define CONNMAN_API_SUBJECT_TO_CHANGE
  36 #include <connman/plugin.h>
  37 #include <connman/log.h>
  38 #include <connman/session.h>
  39 #include <connman/dbus.h>
  40 #include <connman/inotify.h>
  41
  42 #define POLICYDIR STORAGEDIR "/session_policy_local"
  43
  44 #define MODE            (S_IRUSR | S_IWUSR | S_IXUSR | S_IRGRP | \
  45                         S_IXGRP | S_IROTH | S_IXOTH)
  46
  47 static DBusConnection *connection;
  48
  49 static GHashTable *policy_hash;
  50 static GHashTable *session_hash;
  51
  52 struct create_data {
  53         struct connman_session *session;
  54 };
  55
  56 struct policy_data {
  57         int refcount;
  58         char *ident;
  59
  60         struct connman_session *session;
  61         struct connman_session_config *config;
  62 };
  63
  64 static void cleanup_policy(gpointer user_data)
  65 {
  66         struct policy_data *policy = user_data;
  67
  68         if (policy->config != NULL)
  69                 g_slist_free(policy->config->allowed_bearers);
  70
  71         g_free(policy->ident);
  72         g_free(policy->config);
  73         g_free(policy);
  74 }
  75
  76 static char *parse_ident(const unsigned char *context)
  77 {
  78         char *str, *ident, **tokens;
  79
  80         /*
  81          * SELinux combines Role-Based Access Control (RBAC), Type
  82          * Enforcment (TE) and optionally Multi-Level Security (MLS).
  83          *
  84          * When SELinux is enabled all processes and files are labeled
  85          * with a contex that contains information such as user, role
  86          * type (and optionally a level). E.g.
  87          *
  88          * $ ls -Z
  89          * -rwxrwxr-x. wagi wagi unconfined_u:object_r:haifux_exec_t:s0 session_ui.py
  90          *
  91          * For identifyng application we (ab)using the type
  92          * information. In the above example the haifux_exec_t type
  93          * will be transfered to haifux_t as defined in the domain
  94          * transition and thus we are able to identify the application
  95          * as haifux_t.
  96          */
  97
  98         str = g_strdup((const gchar*)context);
  99         if (str == NULL)
 100                 return NULL;
 101
 102         DBG("SELinux context %s", str);
 103
 104         tokens = g_strsplit(str, ":", 0);
 105         if (tokens == NULL) {
 106                 g_free(str);
 107                 return NULL;
 108         }
 109
 110         /* Use the SELinux type as identification token. */
 111         ident = g_strdup(tokens[2]);
 112
 113         g_strfreev(tokens);
 114         g_free(str);
 115
 116         return ident;
 117 }
 118
 119 static struct policy_data *create_policy(const char *ident)
 120 {
 121         struct policy_data *policy;
 122
 123         DBG("ident %s", ident);
 124
 125         policy = g_new0(struct policy_data, 1);
 126         policy->refcount = 1;
 127
 128         policy->config = connman_session_create_default_config();
 129         policy->ident = g_strdup(ident);
 130
 131         g_hash_table_replace(policy_hash, policy->ident, policy);
 132
 133         return policy;
 134 }
 135
 136 static struct policy_data *policy_ref(struct policy_data *policy)
 137 {
 138         DBG("%p %s ref %d", policy, policy->ident, policy->refcount + 1);
 139
 140         __sync_fetch_and_add(&policy->refcount, 1);
 141
 142         return policy;
 143 }
 144
 145 static void policy_unref(struct policy_data *policy)
 146 {
 147         DBG(" %p %s ref %d", policy, policy->ident, policy->refcount - 1);
 148
 149         if (__sync_fetch_and_sub(&policy->refcount, 1) != 1)
 150                 return;
 151
 152         g_hash_table_remove(policy_hash, policy->ident);
 153 };
 154
 155 static void selinux_context_reply(const unsigned char *context, void *user_data,
 156                                         int err)
 157 {
 158         struct cb_data *cbd = user_data;
 159         connman_session_config_func_t cb = cbd->cb;
 160         struct create_data *data = cbd->data;
 161         struct policy_data *policy;
 162         struct connman_session_config *config = NULL;
 163         char *ident = NULL;
 164
 165         DBG("session %p", data->session);
 166
 167         if (err < 0)
 168                 goto done;
 169
 170         ident = parse_ident(context);
 171         if (ident == NULL) {
 172                 err = -EINVAL;
 173                 goto done;
 174         }
 175
 176         policy = g_hash_table_lookup(policy_hash, ident);
 177         if (policy != NULL) {
 178                 policy_ref(policy);
 179                 policy->session = data->session;
 180         } else
 181                 policy = create_policy(ident);
 182
 183         g_hash_table_replace(session_hash, data->session, policy);
 184         config = policy->config;
 185
 186 done:
 187         (*cb)(data->session, config, cbd->user_data, err);
 188
 189         g_free(cbd);
 190         g_free(data);
 191         g_free(ident);
 192 }
 193
 194 static int policy_local_create(struct connman_session *session,
 195                                 connman_session_config_func_t cb,
 196                                 void *user_data)
 197 {
 198         struct cb_data *cbd = cb_data_new(cb, user_data);
 199         struct create_data *data;
 200         const char *owner;
 201         int err;
 202
 203         DBG("session %p", session);
 204
 205         data = g_new0(struct create_data, 1);
 206         cbd->data = data;
 207
 208         data->session = session;
 209
 210         owner = connman_session_get_owner(session);
 211
 212         err = connman_dbus_get_selinux_context(connection, owner,
 213                                         selinux_context_reply,
 214                                         cbd);
 215         if (err < 0) {
 216                 connman_error("Could not get SELinux context");
 217                 g_free(data);
 218                 g_free(cbd);
 219                 return err;
 220         }
 221
 222         return 0;
 223 }
 224
 225 static void policy_local_destroy(struct connman_session *session)
 226 {
 227         struct policy_data *policy;
 228
 229         DBG("session %p", session);
 230
 231         policy = g_hash_table_lookup(session_hash, session);
 232         if (policy == NULL)
 233                 return;
 234
 235         g_hash_table_remove(session_hash, session);
 236         policy->session = NULL;
 237         policy_unref(policy);
 238 }
 239
 240 static struct connman_session_policy session_policy_local = {
 241         .name = "session local policy configuration",
 242         .priority = CONNMAN_SESSION_POLICY_PRIORITY_DEFAULT,
 243         .create = policy_local_create,
 244         .destroy = policy_local_destroy,
 245 };
 246
 247 static int load_keyfile(const char *pathname, GKeyFile **keyfile)
 248 {
 249         GError *error = NULL;
 250         int err;
 251
 252         DBG("Loading %s", pathname);
 253
 254         *keyfile = g_key_file_new();
 255
 256         if (g_key_file_load_from_file(*keyfile, pathname, 0, &error) == FALSE)
 257                 goto err;
 258
 259         return 0;
 260
 261 err:
 262         /*
 263          * The fancy G_FILE_ERROR_* codes are identical to the native
 264          * error codes.
 265          */
 266         err = -error->code;
 267
 268         DBG("Unable to load %s: %s", pathname, error->message);
 269         g_clear_error(&error);
 270
 271         g_key_file_free(*keyfile);
 272         *keyfile = NULL;
 273
 274         return err;
 275 }
 276
 277 static int load_policy(struct policy_data *policy)
 278 {
 279         struct connman_session_config *config = policy->config;
 280         GKeyFile *keyfile;
 281         char *pathname;
 282         char *str, **tokens;
 283         int i, err = 0;
 284
 285         connman_session_set_default_config(config);
 286
 287         pathname = g_strdup_printf("%s/%s", POLICYDIR, policy->ident);
 288
 289         err = load_keyfile(pathname, &keyfile);
 290         if (err < 0) {
 291                 g_free(pathname);
 292
 293                 if (err == -ENOENT) {
 294                         /* Ignore empty files */
 295                         return 0;
 296                 }
 297
 298                 return err;
 299         }
 300
 301         config->priority = g_key_file_get_boolean(keyfile, "Default",
 302                                                 "Priority", NULL);
 303
 304         str = g_key_file_get_string(keyfile, "Default", "RoamingPolicy",
 305                                 NULL);
 306         if (str != NULL) {
 307                 config->roaming_policy = connman_session_parse_roaming_policy(str);
 308                 g_free(str);
 309         }
 310
 311         str = g_key_file_get_string(keyfile, "Default", "ConnectionType",
 312                                 NULL);
 313         if (str != NULL) {
 314                 config->type = connman_session_parse_connection_type(str);
 315                 g_free(str);
 316         }
 317
 318         config->ecall = g_key_file_get_boolean(keyfile, "Default",
 319                                                 "EmergencyCall", NULL);
 320
 321         str = g_key_file_get_string(keyfile, "Default", "AllowedBearers",
 322                                 NULL);
 323
 324         if (str != NULL) {
 325                 g_slist_free(config->allowed_bearers);
 326                 config->allowed_bearers = NULL;
 327
 328                 tokens = g_strsplit(str, " ", 0);
 329
 330                 for (i = 0; tokens[i] != NULL; i++) {
 331                         err = connman_session_parse_bearers(tokens[i],
 332                                         &config->allowed_bearers);
 333                         if (err < 0)
 334                                 break;
 335                 }
 336
 337                 g_free(str);
 338                 g_strfreev(tokens);
 339         }
 340
 341         g_key_file_free(keyfile);
 342         g_free(pathname);
 343
 344         return err;
 345 }
 346
 347 static void update_session(struct connman_session *session)
 348 {
 349         if (connman_session_config_update(session) < 0)
 350                 connman_session_destroy(session);
 351 }
 352
 353 static void remove_policy(struct policy_data *policy)
 354 {
 355         connman_bool_t update = FALSE;
 356
 357         if (policy->session != NULL)
 358                 update = TRUE;
 359
 360         policy_unref(policy);
 361
 362         if (update == FALSE)
 363                 return;
 364
 365         connman_session_set_default_config(policy->config);
 366         update_session(policy->session);
 367 }
 368
 369 static void notify_handler(struct inotify_event *event,
 370                                         const char *ident)
 371 {
 372         struct policy_data *policy;
 373         int err;
 374
 375         if (ident == NULL)
 376                 return;
 377
 378         policy = g_hash_table_lookup(policy_hash, ident);
 379
 380         if (event->mask & (IN_CREATE | IN_MOVED_TO)) {
 381                 connman_info("Policy added for '%s'", ident);
 382
 383                 if (policy != NULL)
 384                         policy_ref(policy);
 385                 else
 386                         policy = create_policy(ident);
 387
 388                 err = load_policy(policy);
 389                 if (err < 0) {
 390                         connman_warn("Loading policy file '%s' failed with %s",
 391                                         ident, strerror(-err));
 392                         return;
 393                 }
 394         }
 395
 396         if (policy == NULL)
 397                 return;
 398
 399         if (event->mask & IN_MODIFY) {
 400                 connman_info("Policy modifed for '%s'", ident);
 401
 402                 err = load_policy(policy);
 403                 if (err < 0) {
 404                         connman_warn("Loading policy file '%s' failed with %s",
 405                                         ident, strerror(-err));
 406                         return;
 407                 }
 408         }
 409
 410         if (event->mask & (IN_DELETE | IN_MOVED_FROM)) {
 411                 connman_info("Policy deleted for '%s'", ident);
 412
 413                 remove_policy(policy);
 414                 return;
 415         }
 416
 417         if (policy->session != NULL)
 418                 update_session(policy->session);
 419 }
 420
 421 static int read_policies(void)
 422 {
 423         GDir *dir;
 424         int err = 0;
 425
 426         DBG("");
 427
 428         dir = g_dir_open(POLICYDIR, 0, NULL);
 429         if (dir != NULL) {
 430                 const gchar *file;
 431
 432                 while ((file = g_dir_read_name(dir)) != NULL) {
 433                         struct policy_data *policy;
 434
 435                         policy = create_policy(file);
 436                         err = load_policy(policy);
 437                         if (err < 0)
 438                                 break;
 439                 }
 440
 441                 g_dir_close(dir);
 442         }
 443
 444         return err;
 445 }
 446
 447 static int session_policy_local_init(void)
 448 {
 449         int err;
 450
 451         /* If the dir doesn't exist, create it */
 452         if (g_file_test(POLICYDIR, G_FILE_TEST_IS_DIR) == FALSE) {
 453                 if (mkdir(POLICYDIR, MODE) < 0) {
 454                         if (errno != EEXIST)
 455                                 return -errno;
 456                 }
 457         }
 458
 459         connection = connman_dbus_get_connection();
 460         if (connection == NULL)
 461                 return -EIO;
 462
 463         session_hash = g_hash_table_new_full(g_direct_hash, g_direct_equal,
 464                                                 NULL, NULL);
 465         policy_hash = g_hash_table_new_full(g_str_hash, g_str_equal,
 466                                         NULL, cleanup_policy);
 467
 468         err = connman_inotify_register(POLICYDIR, notify_handler);
 469         if (err < 0)
 470                 goto err;
 471
 472         err = read_policies();
 473         if (err < 0)
 474                 goto err_notify;
 475
 476         err = connman_session_policy_register(&session_policy_local);
 477         if (err < 0)
 478                 goto err_notify;
 479
 480         return 0;
 481
 482 err_notify:
 483
 484         connman_inotify_unregister(POLICYDIR, notify_handler);
 485
 486 err:
 487         if (session_hash != NULL)
 488                 g_hash_table_destroy(session_hash);
 489         if (policy_hash != NULL)
 490                 g_hash_table_destroy(policy_hash);
 491
 492         connman_session_policy_unregister(&session_policy_local);
 493
 494         dbus_connection_unref(connection);
 495
 496         return err;
 497 }
 498
 499 static void session_policy_local_exit(void)
 500 {
 501         g_hash_table_destroy(session_hash);
 502         g_hash_table_destroy(policy_hash);
 503
 504         connman_session_policy_unregister(&session_policy_local);
 505
 506         dbus_connection_unref(connection);
 507
 508         connman_inotify_unregister(POLICYDIR, notify_handler);
 509 }
 510
 511 CONNMAN_PLUGIN_DEFINE(session_policy_local,
 512                 "Session local file policy configuration plugin",
 513                 VERSION, CONNMAN_PLUGIN_PRIORITY_DEFAULT,
 514                 session_policy_local_init, session_policy_local_exit)