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         connman_session_config_cb callback;
  55         void *user_data;
  56 };
  57
  58 struct policy_data {
  59         int refcount;
  60         char *ident;
  61
  62         struct connman_session *session;
  63         struct connman_session_config *config;
  64 };
  65
  66 static void cleanup_policy(gpointer user_data)
  67 {
  68         struct policy_data *policy = user_data;
  69
  70         if (policy->config != NULL)
  71                 g_slist_free(policy->config->allowed_bearers);
  72
  73         g_free(policy->ident);
  74         g_free(policy->config);
  75         g_free(policy);
  76 }
  77
  78 static char *parse_ident(const unsigned char *context)
  79 {
  80         char *str, *ident, **tokens;
  81
  82         /*
  83          * SELinux combines Role-Based Access Control (RBAC), Type
  84          * Enforcment (TE) and optionally Multi-Level Security (MLS).
  85          *
  86          * When SELinux is enabled all processes and files are labeled
  87          * with a contex that contains information such as user, role
  88          * type (and optionally a level). E.g.
  89          *
  90          * $ ls -Z
  91          * -rwxrwxr-x. wagi wagi unconfined_u:object_r:haifux_exec_t:s0 session_ui.py
  92          *
  93          * For identifyng application we (ab)using the type
  94          * information. In the above example the haifux_exec_t type
  95          * will be transfered to haifux_t as defined in the domain
  96          * transition and thus we are able to identify the application
  97          * as haifux_t.
  98          */
  99
 100         str = g_strdup((const gchar*)context);
 101         if (str == NULL)
 102                 return NULL;
 103
 104         DBG("SELinux context %s", str);
 105
 106         tokens = g_strsplit(str, ":", 0);
 107         if (tokens == NULL) {
 108                 g_free(str);
 109                 return NULL;
 110         }
 111
 112         /* Use the SELinux type as identification token. */
 113         ident = g_strdup(tokens[2]);
 114
 115         g_strfreev(tokens);
 116         g_free(str);
 117
 118         return ident;
 119 }
 120
 121 static struct policy_data *create_policy(const char *ident)
 122 {
 123         struct policy_data *policy;
 124
 125         DBG("ident %s", ident);
 126
 127         policy = g_try_new0(struct policy_data, 1);
 128         if (policy == NULL)
 129                 return NULL;
 130
 131         policy->config = connman_session_create_default_config();
 132         if (policy->config == NULL) {
 133                 g_free(policy);
 134                 return NULL;
 135         }
 136
 137         policy->refcount = 1;
 138         policy->ident = g_strdup(ident);
 139
 140         g_hash_table_replace(policy_hash, policy->ident, policy);
 141
 142         return policy;
 143 }
 144
 145 static struct policy_data *policy_ref(struct policy_data *policy)
 146 {
 147         DBG("%p %s ref %d", policy, policy->ident, policy->refcount + 1);
 148
 149         __sync_fetch_and_add(&policy->refcount, 1);
 150
 151         return policy;
 152 }
 153
 154 static void policy_unref(struct policy_data *policy)
 155 {
 156         DBG(" %p %s ref %d", policy, policy->ident, policy->refcount - 1);
 157
 158         if (__sync_fetch_and_sub(&policy->refcount, 1) != 1)
 159                 return;
 160
 161         g_hash_table_remove(policy_hash, policy->ident);
 162 };
 163
 164 static void selinux_context_reply(const unsigned char *context, void *user_data,
 165                                         int err)
 166 {
 167         struct create_data *data = user_data;
 168         struct policy_data *policy;
 169         struct connman_session_config *config = NULL;
 170         char *ident = NULL;
 171
 172         DBG("session %p", data->session);
 173
 174         if (err < 0)
 175                 goto done;
 176
 177         ident = parse_ident(context);
 178         if (ident == NULL) {
 179                 err = -EINVAL;
 180                 goto done;
 181         }
 182
 183         policy = g_hash_table_lookup(policy_hash, ident);
 184         if (policy != NULL) {
 185                 policy_ref(policy);
 186                 policy->session = data->session;
 187         } else {
 188                 policy = create_policy(ident);
 189                 if (policy == NULL) {
 190                         err = -ENOMEM;
 191                         goto done;
 192                 }
 193         }
 194
 195         g_hash_table_replace(session_hash, data->session, policy);
 196         config = policy->config;
 197
 198 done:
 199         (*data->callback)(data->session, config, data->user_data, err);
 200
 201         g_free(data);
 202         g_free(ident);
 203 }
 204
 205 static int policy_local_create(struct connman_session *session,
 206                                 connman_session_config_cb callback,
 207                                 void *user_data)
 208 {
 209         struct create_data *data;
 210         const char *owner;
 211         int err;
 212
 213         DBG("session %p", session);
 214
 215         data = g_try_new0(struct create_data, 1);
 216         if (data == NULL)
 217                 return -ENOMEM;
 218
 219         data->session = session;
 220         data->callback = callback;
 221         data->user_data = user_data;
 222
 223         owner = connman_session_get_owner(session);
 224
 225         err = connman_dbus_get_selinux_context(connection, owner,
 226                                         selinux_context_reply,
 227                                         data);
 228         if (err < 0) {
 229                 connman_error("Could not get SELinux context");
 230                 g_free(data);
 231                 return err;
 232         }
 233
 234         return 0;
 235 }
 236
 237 static void policy_local_destroy(struct connman_session *session)
 238 {
 239         struct policy_data *policy;
 240
 241         DBG("session %p", session);
 242
 243         policy = g_hash_table_lookup(session_hash, session);
 244         g_hash_table_remove(session_hash, session);
 245         policy->session = NULL;
 246
 247         policy_unref(policy);
 248 }
 249
 250 static struct connman_session_policy session_policy_local = {
 251         .name = "session local policy configuration",
 252         .priority = CONNMAN_SESSION_POLICY_PRIORITY_DEFAULT,
 253         .create = policy_local_create,
 254         .destroy = policy_local_destroy,
 255 };
 256
 257 static int load_keyfile(const char *pathname, GKeyFile **keyfile)
 258 {
 259         GError *error = NULL;
 260         int err;
 261
 262         DBG("Loading %s", pathname);
 263
 264         *keyfile = g_key_file_new();
 265
 266         if (g_key_file_load_from_file(*keyfile, pathname, 0, &error) == FALSE)
 267                 goto err;
 268
 269         return 0;
 270
 271 err:
 272         /*
 273          * The fancy G_FILE_ERROR_* codes are identical to the native
 274          * error codes.
 275          */
 276         err = -error->code;
 277
 278         DBG("Unable to load %s: %s", pathname, error->message);
 279         g_clear_error(&error);
 280
 281         g_key_file_free(*keyfile);
 282         *keyfile = NULL;
 283
 284         return err;
 285 }
 286
 287 static int load_policy(struct policy_data *policy)
 288 {
 289         struct connman_session_config *config = policy->config;
 290         GKeyFile *keyfile;
 291         char *pathname;
 292         char *str, **tokens;
 293         int i, err = 0;
 294
 295         pathname = g_strdup_printf("%s/%s", POLICYDIR, policy->ident);
 296         if(pathname == NULL)
 297                 return -ENOMEM;
 298
 299         err = load_keyfile(pathname, &keyfile);
 300         if (err < 0) {
 301                 g_free(pathname);
 302
 303                 if (err == -ENOENT) {
 304                         /* Ignore empty files */
 305                         return 0;
 306                 }
 307
 308                 return err;
 309         }
 310
 311         config->priority = g_key_file_get_boolean(keyfile, "Default",
 312                                                 "Priority", NULL);
 313
 314         str = g_key_file_get_string(keyfile, "Default", "RoamingPolicy",
 315                                 NULL);
 316         if (str != NULL) {
 317                 config->roaming_policy = connman_session_parse_roaming_policy(str);
 318                 g_free(str);
 319         } else {
 320                 config->roaming_policy = CONNMAN_SESSION_ROAMING_POLICY_DEFAULT;
 321         }
 322
 323         str = g_key_file_get_string(keyfile, "Default", "ConnectionType",
 324                                 NULL);
 325         if (str != NULL) {
 326                 config->type = connman_session_parse_connection_type(str);
 327                 g_free(str);
 328         } else {
 329                 config->type = CONNMAN_SESSION_TYPE_ANY;
 330         }
 331
 332         config->ecall = g_key_file_get_boolean(keyfile, "Default",
 333                                                 "EmergencyCall", NULL);
 334
 335         g_slist_free(config->allowed_bearers);
 336         config->allowed_bearers = NULL;
 337
 338         str = g_key_file_get_string(keyfile, "Default", "AllowedBearers",
 339                                 NULL);
 340
 341         if (str != NULL) {
 342                 tokens = g_strsplit(str, " ", 0);
 343
 344                 for (i = 0; tokens[i] != NULL; i++) {
 345                         err = connman_session_parse_bearers(tokens[i],
 346                                         &config->allowed_bearers);
 347                         if (err < 0)
 348                                 break;
 349                 }
 350
 351                 g_free(str);
 352                 g_strfreev(tokens);
 353         } else {
 354                 config->allowed_bearers = g_slist_append(NULL,
 355                                 GINT_TO_POINTER(CONNMAN_SERVICE_TYPE_UNKNOWN));
 356                 if (config->allowed_bearers == NULL)
 357                         err = -ENOMEM;
 358         }
 359
 360         g_key_file_free(keyfile);
 361         g_free(pathname);
 362
 363         return err;
 364 }
 365
 366 static void update_session(struct connman_session *session)
 367 {
 368         if (connman_session_config_update(session) < 0)
 369                 connman_session_destroy(session);
 370 }
 371
 372 static void remove_policy(struct policy_data *policy)
 373 {
 374         connman_bool_t update = FALSE;
 375         int err;
 376
 377         if (policy->session != NULL)
 378                 update = TRUE;
 379
 380         policy_unref(policy);
 381
 382         if (update == FALSE)
 383                 return;
 384
 385         err = connman_session_set_default_config(policy->config);
 386         if (err < 0) {
 387                 connman_session_destroy(policy->session);
 388                 return;
 389         }
 390
 391         update_session(policy->session);
 392 }
 393
 394 static void notify_handler(struct inotify_event *event,
 395                                         const char *ident)
 396 {
 397         struct policy_data *policy;
 398
 399         if (ident == NULL)
 400                 return;
 401
 402         policy = g_hash_table_lookup(policy_hash, ident);
 403
 404         if (event->mask & (IN_CREATE | IN_MOVED_TO)) {
 405                 connman_info("Policy added for '%s'", ident);
 406
 407                 if (policy != NULL)
 408                         policy_ref(policy);
 409                 else
 410                         policy = create_policy(ident);
 411         }
 412
 413         if (policy == NULL)
 414                 return;
 415
 416         if (event->mask & IN_MODIFY) {
 417                 connman_info("Policy modifed for '%s'", ident);
 418
 419                 if (load_policy(policy) < 0) {
 420                         remove_policy(policy);
 421                         return;
 422                 }
 423         }
 424
 425         if (event->mask & (IN_DELETE | IN_MOVED_FROM)) {
 426                 connman_info("Policy deleted for '%s'", ident);
 427
 428                 remove_policy(policy);
 429                 return;
 430         }
 431
 432         if (policy->session != NULL)
 433                 update_session(policy->session);
 434 }
 435
 436 static int read_policies(void)
 437 {
 438         GDir *dir;
 439         int err = 0;
 440
 441         DBG("");
 442
 443         dir = g_dir_open(POLICYDIR, 0, NULL);
 444         if (dir != NULL) {
 445                 const gchar *file;
 446
 447                 while ((file = g_dir_read_name(dir)) != NULL) {
 448                         struct policy_data *policy;
 449
 450                         policy = create_policy(file);
 451                         if (policy == NULL) {
 452                                 err = -ENOMEM;
 453                                 break;
 454                         }
 455
 456                         err = load_policy(policy);
 457                         if (err < 0)
 458                                 break;
 459                 }
 460
 461                 g_dir_close(dir);
 462         }
 463
 464         return err;
 465 }
 466
 467 static int session_policy_local_init(void)
 468 {
 469         int err;
 470
 471         /* If the dir doesn't exist, create it */
 472         if (g_file_test(POLICYDIR, G_FILE_TEST_IS_DIR) == FALSE) {
 473                 if (mkdir(POLICYDIR, MODE) < 0) {
 474                         if (errno != EEXIST)
 475                                 return -errno;
 476                 }
 477         }
 478
 479         connection = connman_dbus_get_connection();
 480         if (connection == NULL)
 481                 return -EIO;
 482
 483         session_hash = g_hash_table_new_full(g_direct_hash, g_direct_equal,
 484                                                 NULL, NULL);
 485         if (session_hash == NULL) {
 486                 err = -ENOMEM;
 487                 goto err;
 488         }
 489
 490         policy_hash = g_hash_table_new_full(g_str_hash, g_str_equal,
 491                                         NULL, cleanup_policy);
 492         if (policy_hash == NULL) {
 493                 err = -ENOMEM;
 494                 goto err;
 495         }
 496
 497         err = connman_inotify_register(POLICYDIR, notify_handler);
 498         if (err < 0)
 499                 goto err;
 500
 501         err = read_policies();
 502         if (err < 0)
 503                 goto err_notify;
 504
 505         err = connman_session_policy_register(&session_policy_local);
 506         if (err < 0)
 507                 goto err_notify;
 508
 509         return 0;
 510
 511 err_notify:
 512
 513         connman_inotify_unregister(POLICYDIR, notify_handler);
 514
 515 err:
 516         if (session_hash != NULL)
 517                 g_hash_table_destroy(session_hash);
 518         if (policy_hash != NULL)
 519                 g_hash_table_destroy(policy_hash);
 520
 521         connman_session_policy_unregister(&session_policy_local);
 522
 523         dbus_connection_unref(connection);
 524
 525         return err;
 526 }
 527
 528 static void session_policy_local_exit(void)
 529 {
 530         g_hash_table_destroy(session_hash);
 531         g_hash_table_destroy(policy_hash);
 532
 533         connman_session_policy_unregister(&session_policy_local);
 534
 535         dbus_connection_unref(connection);
 536
 537         connman_inotify_unregister(POLICYDIR, notify_handler);
 538 }
 539
 540 CONNMAN_PLUGIN_DEFINE(session_policy_local,
 541                 "Session local file policy configuration plugin",
 542                 VERSION, CONNMAN_PLUGIN_PRIORITY_DEFAULT,
 543                 session_policy_local_init, session_policy_local_exit)