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_try_new0(struct policy_data, 1);
 126         if (policy == NULL)
 127                 return NULL;
 128
 129         policy->config = connman_session_create_default_config();
 130         policy->refcount = 1;
 131         policy->ident = g_strdup(ident);
 132
 133         g_hash_table_replace(policy_hash, policy->ident, policy);
 134
 135         return policy;
 136 }
 137
 138 static struct policy_data *policy_ref(struct policy_data *policy)
 139 {
 140         DBG("%p %s ref %d", policy, policy->ident, policy->refcount + 1);
 141
 142         __sync_fetch_and_add(&policy->refcount, 1);
 143
 144         return policy;
 145 }
 146
 147 static void policy_unref(struct policy_data *policy)
 148 {
 149         DBG(" %p %s ref %d", policy, policy->ident, policy->refcount - 1);
 150
 151         if (__sync_fetch_and_sub(&policy->refcount, 1) != 1)
 152                 return;
 153
 154         g_hash_table_remove(policy_hash, policy->ident);
 155 };
 156
 157 static void selinux_context_reply(const unsigned char *context, void *user_data,
 158                                         int err)
 159 {
 160         struct cb_data *cbd = user_data;
 161         connman_session_config_func_t cb = cbd->cb;
 162         struct create_data *data = cbd->data;
 163         struct policy_data *policy;
 164         struct connman_session_config *config = NULL;
 165         char *ident = NULL;
 166
 167         DBG("session %p", data->session);
 168
 169         if (err < 0)
 170                 goto done;
 171
 172         ident = parse_ident(context);
 173         if (ident == NULL) {
 174                 err = -EINVAL;
 175                 goto done;
 176         }
 177
 178         policy = g_hash_table_lookup(policy_hash, ident);
 179         if (policy != NULL) {
 180                 policy_ref(policy);
 181                 policy->session = data->session;
 182         } else {
 183                 policy = create_policy(ident);
 184                 if (policy == NULL) {
 185                         err = -ENOMEM;
 186                         goto done;
 187                 }
 188         }
 189
 190         g_hash_table_replace(session_hash, data->session, policy);
 191         config = policy->config;
 192
 193 done:
 194         (*cb)(data->session, config, cbd->user_data, err);
 195
 196         g_free(cbd);
 197         g_free(data);
 198         g_free(ident);
 199 }
 200
 201 static int policy_local_create(struct connman_session *session,
 202                                 connman_session_config_func_t cb,
 203                                 void *user_data)
 204 {
 205         struct cb_data *cbd = cb_data_new(cb, user_data);
 206         struct create_data *data;
 207         const char *owner;
 208         int err;
 209
 210         DBG("session %p", session);
 211
 212         data = g_try_new0(struct create_data, 1);
 213         if (data == NULL)
 214                 return -ENOMEM;
 215         cbd->data = data;
 216
 217         data->session = session;
 218
 219         owner = connman_session_get_owner(session);
 220
 221         err = connman_dbus_get_selinux_context(connection, owner,
 222                                         selinux_context_reply,
 223                                         cbd);
 224         if (err < 0) {
 225                 connman_error("Could not get SELinux context");
 226                 g_free(data);
 227                 g_free(cbd);
 228                 return err;
 229         }
 230
 231         return 0;
 232 }
 233
 234 static void policy_local_destroy(struct connman_session *session)
 235 {
 236         struct policy_data *policy;
 237
 238         DBG("session %p", session);
 239
 240         policy = g_hash_table_lookup(session_hash, session);
 241         if (policy == NULL)
 242                 return;
 243
 244         g_hash_table_remove(session_hash, session);
 245         policy->session = NULL;
 246         policy_unref(policy);
 247 }
 248
 249 static struct connman_session_policy session_policy_local = {
 250         .name = "session local policy configuration",
 251         .priority = CONNMAN_SESSION_POLICY_PRIORITY_DEFAULT,
 252         .create = policy_local_create,
 253         .destroy = policy_local_destroy,
 254 };
 255
 256 static int load_keyfile(const char *pathname, GKeyFile **keyfile)
 257 {
 258         GError *error = NULL;
 259         int err;
 260
 261         DBG("Loading %s", pathname);
 262
 263         *keyfile = g_key_file_new();
 264
 265         if (g_key_file_load_from_file(*keyfile, pathname, 0, &error) == FALSE)
 266                 goto err;
 267
 268         return 0;
 269
 270 err:
 271         /*
 272          * The fancy G_FILE_ERROR_* codes are identical to the native
 273          * error codes.
 274          */
 275         err = -error->code;
 276
 277         DBG("Unable to load %s: %s", pathname, error->message);
 278         g_clear_error(&error);
 279
 280         g_key_file_free(*keyfile);
 281         *keyfile = NULL;
 282
 283         return err;
 284 }
 285
 286 static int load_policy(struct policy_data *policy)
 287 {
 288         struct connman_session_config *config = policy->config;
 289         GKeyFile *keyfile;
 290         char *pathname;
 291         char *str, **tokens;
 292         int i, err = 0;
 293
 294         connman_session_set_default_config(config);
 295
 296         pathname = g_strdup_printf("%s/%s", POLICYDIR, policy->ident);
 297         if(pathname == NULL)
 298                 return -ENOMEM;
 299
 300         err = load_keyfile(pathname, &keyfile);
 301         if (err < 0) {
 302                 g_free(pathname);
 303
 304                 if (err == -ENOENT) {
 305                         /* Ignore empty files */
 306                         return 0;
 307                 }
 308
 309                 return err;
 310         }
 311
 312         config->priority = g_key_file_get_boolean(keyfile, "Default",
 313                                                 "Priority", NULL);
 314
 315         str = g_key_file_get_string(keyfile, "Default", "RoamingPolicy",
 316                                 NULL);
 317         if (str != NULL) {
 318                 config->roaming_policy = connman_session_parse_roaming_policy(str);
 319                 g_free(str);
 320         }
 321
 322         str = g_key_file_get_string(keyfile, "Default", "ConnectionType",
 323                                 NULL);
 324         if (str != NULL) {
 325                 config->type = connman_session_parse_connection_type(str);
 326                 g_free(str);
 327         }
 328
 329         config->ecall = g_key_file_get_boolean(keyfile, "Default",
 330                                                 "EmergencyCall", NULL);
 331
 332         str = g_key_file_get_string(keyfile, "Default", "AllowedBearers",
 333                                 NULL);
 334
 335         if (str != NULL) {
 336                 g_slist_free(config->allowed_bearers);
 337                 config->allowed_bearers = NULL;
 338
 339                 tokens = g_strsplit(str, " ", 0);
 340
 341                 for (i = 0; tokens[i] != NULL; i++) {
 342                         err = connman_session_parse_bearers(tokens[i],
 343                                         &config->allowed_bearers);
 344                         if (err < 0)
 345                                 break;
 346                 }
 347
 348                 g_free(str);
 349                 g_strfreev(tokens);
 350         }
 351
 352         g_key_file_free(keyfile);
 353         g_free(pathname);
 354
 355         return err;
 356 }
 357
 358 static void update_session(struct connman_session *session)
 359 {
 360         if (connman_session_config_update(session) < 0)
 361                 connman_session_destroy(session);
 362 }
 363
 364 static void remove_policy(struct policy_data *policy)
 365 {
 366         connman_bool_t update = FALSE;
 367
 368         if (policy->session != NULL)
 369                 update = TRUE;
 370
 371         policy_unref(policy);
 372
 373         if (update == FALSE)
 374                 return;
 375
 376         connman_session_set_default_config(policy->config);
 377         update_session(policy->session);
 378 }
 379
 380 static void notify_handler(struct inotify_event *event,
 381                                         const char *ident)
 382 {
 383         struct policy_data *policy;
 384         int err;
 385
 386         if (ident == NULL)
 387                 return;
 388
 389         policy = g_hash_table_lookup(policy_hash, ident);
 390
 391         if (event->mask & (IN_CREATE | IN_MOVED_TO)) {
 392                 connman_info("Policy added for '%s'", ident);
 393
 394                 if (policy != NULL)
 395                         policy_ref(policy);
 396                 else
 397                         policy = create_policy(ident);
 398
 399                 err = load_policy(policy);
 400                 if (err < 0) {
 401                         connman_warn("Loading policy file '%s' failed with %s",
 402                                         ident, strerror(-err));
 403                         return;
 404                 }
 405         }
 406
 407         if (policy == NULL)
 408                 return;
 409
 410         if (event->mask & IN_MODIFY) {
 411                 connman_info("Policy modifed for '%s'", ident);
 412
 413                 err = load_policy(policy);
 414                 if (err < 0) {
 415                         connman_warn("Loading policy file '%s' failed with %s",
 416                                         ident, strerror(-err));
 417                         return;
 418                 }
 419         }
 420
 421         if (event->mask & (IN_DELETE | IN_MOVED_FROM)) {
 422                 connman_info("Policy deleted for '%s'", ident);
 423
 424                 remove_policy(policy);
 425                 return;
 426         }
 427
 428         if (policy->session != NULL)
 429                 update_session(policy->session);
 430 }
 431
 432 static int read_policies(void)
 433 {
 434         GDir *dir;
 435         int err = 0;
 436
 437         DBG("");
 438
 439         dir = g_dir_open(POLICYDIR, 0, NULL);
 440         if (dir != NULL) {
 441                 const gchar *file;
 442
 443                 while ((file = g_dir_read_name(dir)) != NULL) {
 444                         struct policy_data *policy;
 445
 446                         policy = create_policy(file);
 447                         if (policy == NULL) {
 448                                 err = -ENOMEM;
 449                                 break;
 450                         }
 451
 452                         err = load_policy(policy);
 453                         if (err < 0)
 454                                 break;
 455                 }
 456
 457                 g_dir_close(dir);
 458         }
 459
 460         return err;
 461 }
 462
 463 static int session_policy_local_init(void)
 464 {
 465         int err;
 466
 467         /* If the dir doesn't exist, create it */
 468         if (g_file_test(POLICYDIR, G_FILE_TEST_IS_DIR) == FALSE) {
 469                 if (mkdir(POLICYDIR, MODE) < 0) {
 470                         if (errno != EEXIST)
 471                                 return -errno;
 472                 }
 473         }
 474
 475         connection = connman_dbus_get_connection();
 476         if (connection == NULL)
 477                 return -EIO;
 478
 479         session_hash = g_hash_table_new_full(g_direct_hash, g_direct_equal,
 480                                                 NULL, NULL);
 481         if (session_hash == NULL) {
 482                 err = -ENOMEM;
 483                 goto err;
 484         }
 485
 486         policy_hash = g_hash_table_new_full(g_str_hash, g_str_equal,
 487                                         NULL, cleanup_policy);
 488         if (policy_hash == NULL) {
 489                 err = -ENOMEM;
 490                 goto err;
 491         }
 492
 493         err = connman_inotify_register(POLICYDIR, notify_handler);
 494         if (err < 0)
 495                 goto err;
 496
 497         err = read_policies();
 498         if (err < 0)
 499                 goto err_notify;
 500
 501         err = connman_session_policy_register(&session_policy_local);
 502         if (err < 0)
 503                 goto err_notify;
 504
 505         return 0;
 506
 507 err_notify:
 508
 509         connman_inotify_unregister(POLICYDIR, notify_handler);
 510
 511 err:
 512         if (session_hash != NULL)
 513                 g_hash_table_destroy(session_hash);
 514         if (policy_hash != NULL)
 515                 g_hash_table_destroy(policy_hash);
 516
 517         connman_session_policy_unregister(&session_policy_local);
 518
 519         dbus_connection_unref(connection);
 520
 521         return err;
 522 }
 523
 524 static void session_policy_local_exit(void)
 525 {
 526         g_hash_table_destroy(session_hash);
 527         g_hash_table_destroy(policy_hash);
 528
 529         connman_session_policy_unregister(&session_policy_local);
 530
 531         dbus_connection_unref(connection);
 532
 533         connman_inotify_unregister(POLICYDIR, notify_handler);
 534 }
 535
 536 CONNMAN_PLUGIN_DEFINE(session_policy_local,
 537                 "Session local file policy configuration plugin",
 538                 VERSION, CONNMAN_PLUGIN_PRIORITY_DEFAULT,
 539                 session_policy_local_init, session_policy_local_exit)