src/bus-proxyd/bus-policy.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2013 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include "xml.h"
  23 #include "fileio.h"
  24 #include "strv.h"
  25 #include "conf-files.h"
  26 #include "bus-internal.h"
  27 #include "bus-message.h"
  28 #include "bus-policy.h"
  29
  30 static void policy_item_free(PolicyItem *i) {
  31         assert(i);
  32
  33         free(i->interface);
  34         free(i->member);
  35         free(i->error);
  36         free(i->name);
  37         free(i->path);
  38         free(i);
  39 }
  40
  41 DEFINE_TRIVIAL_CLEANUP_FUNC(PolicyItem*, policy_item_free);
  42
  43 static void item_append(PolicyItem *i, PolicyItem **list) {
  44
  45         PolicyItem *tail;
  46
  47         LIST_FIND_TAIL(items, *list, tail);
  48         LIST_INSERT_AFTER(items, *list, tail, i);
  49 }
  50
  51 static int file_load(Policy *p, const char *path) {
  52
  53         _cleanup_free_ char *c = NULL, *policy_user = NULL, *policy_group = NULL;
  54         _cleanup_(policy_item_freep) PolicyItem *i = NULL;
  55         void *xml_state = NULL;
  56         unsigned n_other = 0;
  57         const char *q;
  58         int r;
  59
  60         enum {
  61                 STATE_OUTSIDE,
  62                 STATE_BUSCONFIG,
  63                 STATE_POLICY,
  64                 STATE_POLICY_CONTEXT,
  65                 STATE_POLICY_USER,
  66                 STATE_POLICY_GROUP,
  67                 STATE_POLICY_OTHER_ATTRIBUTE,
  68                 STATE_ALLOW_DENY,
  69                 STATE_ALLOW_DENY_INTERFACE,
  70                 STATE_ALLOW_DENY_MEMBER,
  71                 STATE_ALLOW_DENY_ERROR,
  72                 STATE_ALLOW_DENY_PATH,
  73                 STATE_ALLOW_DENY_MESSAGE_TYPE,
  74                 STATE_ALLOW_DENY_NAME,
  75                 STATE_ALLOW_DENY_OTHER_ATTRIBUTE,
  76                 STATE_OTHER,
  77         } state = STATE_OUTSIDE;
  78
  79         enum {
  80                 POLICY_CATEGORY_NONE,
  81                 POLICY_CATEGORY_DEFAULT,
  82                 POLICY_CATEGORY_MANDATORY,
  83                 POLICY_CATEGORY_USER,
  84                 POLICY_CATEGORY_GROUP
  85         } policy_category = POLICY_CATEGORY_NONE;
  86
  87         unsigned line = 0;
  88
  89         assert(p);
  90
  91         r = read_full_file(path, &c, NULL);
  92         if (r < 0) {
  93                 if (r == -ENOENT)
  94                         return 0;
  95                 if (r == -EISDIR)
  96                         return r;
  97
  98                 log_error("Failed to load %s: %s", path, strerror(-r));
  99                 return r;
 100         }
 101
 102         q = c;
 103         for (;;) {
 104                 _cleanup_free_ char *name = NULL;
 105                 int t;
 106
 107                 t = xml_tokenize(&q, &name, &xml_state, &line);
 108                 if (t < 0) {
 109                         log_error("XML parse failure in %s: %s", path, strerror(-t));
 110                         return t;
 111                 }
 112
 113                 switch (state) {
 114
 115                 case STATE_OUTSIDE:
 116
 117                         if (t == XML_TAG_OPEN) {
 118                                 if (streq(name, "busconfig"))
 119                                         state = STATE_BUSCONFIG;
 120                                 else {
 121                                         log_error("Unexpected tag %s at %s:%u.", name, path, line);
 122                                         return -EINVAL;
 123                                 }
 124
 125                         } else if (t == XML_END)
 126                                 return 0;
 127                         else if (t != XML_TEXT || !in_charset(name, WHITESPACE)) {
 128                                 log_error("Unexpected token (1) at %s:%u.", path, line);
 129                                 return -EINVAL;
 130                         }
 131
 132                         break;
 133
 134                 case STATE_BUSCONFIG:
 135
 136                         if (t == XML_TAG_OPEN) {
 137                                 if (streq(name, "policy")) {
 138                                         state = STATE_POLICY;
 139                                         policy_category = POLICY_CATEGORY_NONE;
 140                                         free(policy_user);
 141                                         free(policy_group);
 142                                         policy_user = policy_group = NULL;
 143                                 } else {
 144                                         state = STATE_OTHER;
 145                                         n_other = 0;
 146                                 }
 147                         } else if (t == XML_TAG_CLOSE_EMPTY ||
 148                                    (t == XML_TAG_CLOSE && streq(name, "busconfig")))
 149                                 state = STATE_OUTSIDE;
 150                         else if (t != XML_TEXT || !in_charset(name, WHITESPACE)) {
 151                                 log_error("Unexpected token (2) at %s:%u.", path, line);
 152                                 return -EINVAL;
 153                         }
 154
 155                         break;
 156
 157                 case STATE_POLICY:
 158
 159                         if (t == XML_ATTRIBUTE_NAME) {
 160                                 if (streq(name, "context"))
 161                                         state = STATE_POLICY_CONTEXT;
 162                                 else if (streq(name, "user"))
 163                                         state = STATE_POLICY_USER;
 164                                 else if (streq(name, "group"))
 165                                         state = STATE_POLICY_GROUP;
 166                                 else {
 167                                         if (streq(name, "at_console"))
 168                                                 log_debug("Attribute %s of <policy> tag unsupported at %s:%u, ignoring.", name, path, line);
 169                                         else
 170                                                 log_warning("Attribute %s of <policy> tag unknown at %s:%u, ignoring.", name, path, line);
 171                                         state = STATE_POLICY_OTHER_ATTRIBUTE;
 172                                 }
 173                         } else if (t == XML_TAG_CLOSE_EMPTY ||
 174                                    (t == XML_TAG_CLOSE && streq(name, "policy")))
 175                                 state = STATE_BUSCONFIG;
 176                         else if (t == XML_TAG_OPEN) {
 177                                 PolicyItemType it;
 178
 179                                 if (streq(name, "allow"))
 180                                         it = POLICY_ITEM_ALLOW;
 181                                 else if (streq(name, "deny"))
 182                                         it = POLICY_ITEM_DENY;
 183                                 else {
 184                                         log_warning("Unknown tag %s in <policy> %s:%u.", name, path, line);
 185                                         return -EINVAL;
 186                                 }
 187
 188                                 assert(!i);
 189                                 i = new0(PolicyItem, 1);
 190                                 if (!i)
 191                                         return log_oom();
 192
 193                                 i->type = it;
 194                                 state = STATE_ALLOW_DENY;
 195
 196                         } else if (t != XML_TEXT || !in_charset(name, WHITESPACE)) {
 197                                 log_error("Unexpected token (3) at %s:%u.", path, line);
 198                                 return -EINVAL;
 199                         }
 200
 201                         break;
 202
 203                 case STATE_POLICY_CONTEXT:
 204
 205                         if (t == XML_ATTRIBUTE_VALUE) {
 206                                 if (streq(name, "default")) {
 207                                         policy_category = POLICY_CATEGORY_DEFAULT;
 208                                         state = STATE_POLICY;
 209                                 } else if (streq(name, "mandatory")) {
 210                                         policy_category = POLICY_CATEGORY_MANDATORY;
 211                                         state = STATE_POLICY;
 212                                 } else {
 213                                         log_error("context= parameter %s unknown for <policy> at %s:%u.", name, path, line);
 214                                         return -EINVAL;
 215                                 }
 216                         } else {
 217                                 log_error("Unexpected token (4) at %s:%u.", path, line);
 218                                 return -EINVAL;
 219                         }
 220
 221                         break;
 222
 223                 case STATE_POLICY_USER:
 224
 225                         if (t == XML_ATTRIBUTE_VALUE) {
 226                                 free(policy_user);
 227                                 policy_user = name;
 228                                 name = NULL;
 229                                 policy_category = POLICY_CATEGORY_USER;
 230                                 state = STATE_POLICY;
 231                         } else {
 232                                 log_error("Unexpected token (5) in %s:%u.", path, line);
 233                                 return -EINVAL;
 234                         }
 235
 236                         break;
 237
 238                 case STATE_POLICY_GROUP:
 239
 240                         if (t == XML_ATTRIBUTE_VALUE) {
 241                                 free(policy_group);
 242                                 policy_group = name;
 243                                 name = NULL;
 244                                 policy_category = POLICY_CATEGORY_GROUP;
 245                                 state = STATE_POLICY;
 246                         } else {
 247                                 log_error("Unexpected token (6) at %s:%u.", path, line);
 248                                 return -EINVAL;
 249                         }
 250
 251                         break;
 252
 253                 case STATE_POLICY_OTHER_ATTRIBUTE:
 254
 255                         if (t == XML_ATTRIBUTE_VALUE)
 256                                 state = STATE_POLICY;
 257                         else {
 258                                 log_error("Unexpected token (7) in %s:%u.", path, line);
 259                                 return -EINVAL;
 260                         }
 261
 262                         break;
 263
 264                 case STATE_ALLOW_DENY:
 265
 266                         assert(i);
 267
 268                         if (t == XML_ATTRIBUTE_NAME) {
 269                                 PolicyItemClass ic;
 270
 271                                 if (startswith(name, "send_"))
 272                                         ic = POLICY_ITEM_SEND;
 273                                 else if (startswith(name, "receive_"))
 274                                         ic = POLICY_ITEM_RECV;
 275                                 else if (streq(name, "own"))
 276                                         ic = POLICY_ITEM_OWN;
 277                                 else if (streq(name, "own_prefix"))
 278                                         ic = POLICY_ITEM_OWN_PREFIX;
 279                                 else if (streq(name, "user"))
 280                                         ic = POLICY_ITEM_USER;
 281                                 else if (streq(name, "group"))
 282                                         ic = POLICY_ITEM_GROUP;
 283                                 else if (streq(name, "eavesdrop")) {
 284                                         log_debug("Unsupported attribute %s= at %s:%u, ignoring.", name, path, line);
 285                                         i->class = POLICY_ITEM_IGNORE;
 286                                         state = STATE_ALLOW_DENY_OTHER_ATTRIBUTE;
 287                                         break;
 288                                 } else {
 289                                         log_error("Unknown attribute %s= at %s:%u, ignoring.", name, path, line);
 290                                         state = STATE_ALLOW_DENY_OTHER_ATTRIBUTE;
 291                                         break;
 292                                 }
 293
 294                                 if (i->class != _POLICY_ITEM_CLASS_UNSET && ic != i->class) {
 295                                         log_error("send_ and receive_ fields mixed on same tag at %s:%u.", path, line);
 296                                         return -EINVAL;
 297                                 }
 298
 299                                 i->class = ic;
 300
 301                                 if (ic == POLICY_ITEM_SEND || ic == POLICY_ITEM_RECV) {
 302                                         const char *u;
 303
 304                                         u = strchr(name, '_');
 305                                         assert(u);
 306
 307                                         u++;
 308
 309                                         if (streq(u, "interface"))
 310                                                 state = STATE_ALLOW_DENY_INTERFACE;
 311                                         else if (streq(u, "member"))
 312                                                 state = STATE_ALLOW_DENY_MEMBER;
 313                                         else if (streq(u, "error"))
 314                                                 state = STATE_ALLOW_DENY_ERROR;
 315                                         else if (streq(u, "path"))
 316                                                 state = STATE_ALLOW_DENY_PATH;
 317                                         else if (streq(u, "type"))
 318                                                 state = STATE_ALLOW_DENY_MESSAGE_TYPE;
 319                                         else if ((streq(u, "destination") && ic == POLICY_ITEM_SEND) ||
 320                                                  (streq(u, "sender") && ic == POLICY_ITEM_RECV))
 321                                                 state = STATE_ALLOW_DENY_NAME;
 322                                         else {
 323                                                 if (streq(u, "requested_reply"))
 324                                                         log_debug("Unsupported attribute %s= at %s:%u, ignoring.", name, path, line);
 325                                                 else
 326                                                         log_error("Unknown attribute %s= at %s:%u, ignoring.", name, path, line);
 327                                                 state = STATE_ALLOW_DENY_OTHER_ATTRIBUTE;
 328                                                 break;
 329                                         }
 330                                 } else
 331                                         state = STATE_ALLOW_DENY_NAME;
 332
 333                         } else if (t == XML_TAG_CLOSE_EMPTY ||
 334                                    (t == XML_TAG_CLOSE && streq(name, i->type == POLICY_ITEM_ALLOW ? "allow" : "deny"))) {
 335
 336                                 if (i->class == _POLICY_ITEM_CLASS_UNSET) {
 337                                         log_error("Policy not set at %s:%u.", path, line);
 338                                         return -EINVAL;
 339                                 }
 340
 341                                 if (policy_category == POLICY_CATEGORY_DEFAULT)
 342                                         item_append(i, &p->default_items);
 343                                 else if (policy_category == POLICY_CATEGORY_MANDATORY)
 344                                         item_append(i, &p->mandatory_items);
 345                                 else if (policy_category == POLICY_CATEGORY_USER) {
 346                                         const char *u = policy_user;
 347
 348                                         assert_cc(sizeof(uid_t) == sizeof(uint32_t));
 349
 350                                         r = hashmap_ensure_allocated(&p->user_items, NULL);
 351                                         if (r < 0)
 352                                                 return log_oom();
 353
 354                                         if (!u) {
 355                                                 log_error("User policy without name");
 356                                                 return -EINVAL;
 357                                         }
 358
 359                                         r = get_user_creds(&u, &i->uid, NULL, NULL, NULL);
 360                                         if (r < 0) {
 361                                                 log_error("Failed to resolve user %s, ignoring policy: %s", u, strerror(-r));
 362                                                 free(i);
 363                                         } else {
 364                                                 PolicyItem *first;
 365
 366                                                 first = hashmap_get(p->user_items, UINT32_TO_PTR(i->uid));
 367                                                 item_append(i, &first);
 368                                                 i->uid_valid = true;
 369
 370                                                 r = hashmap_replace(p->user_items, UINT32_TO_PTR(i->uid), first);
 371                                                 if (r < 0) {
 372                                                         LIST_REMOVE(items, first, i);
 373                                                         return log_oom();
 374                                                 }
 375                                         }
 376
 377                                 } else if (policy_category == POLICY_CATEGORY_GROUP) {
 378                                         const char *g = policy_group;
 379
 380                                         assert_cc(sizeof(gid_t) == sizeof(uint32_t));
 381
 382                                         r = hashmap_ensure_allocated(&p->group_items, NULL);
 383                                         if (r < 0)
 384                                                 return log_oom();
 385
 386                                         if (!g) {
 387                                                 log_error("Group policy without name");
 388                                                 return -EINVAL;
 389                                         }
 390
 391                                         r = get_group_creds(&g, &i->gid);
 392                                         if (r < 0) {
 393                                                 log_error("Failed to resolve group %s, ignoring policy: %s", g, strerror(-r));
 394                                                 free(i);
 395                                         } else {
 396                                                 PolicyItem *first;
 397
 398                                                 first = hashmap_get(p->group_items, UINT32_TO_PTR(i->gid));
 399                                                 item_append(i, &first);
 400                                                 i->gid_valid = true;
 401
 402                                                 r = hashmap_replace(p->group_items, UINT32_TO_PTR(i->gid), first);
 403                                                 if (r < 0) {
 404                                                         LIST_REMOVE(items, first, i);
 405                                                         return log_oom();
 406                                                 }
 407                                         }
 408                                 }
 409
 410                                 state = STATE_POLICY;
 411                                 i = NULL;
 412
 413                         } else if (t != XML_TEXT || !in_charset(name, WHITESPACE)) {
 414                                 log_error("Unexpected token (8) at %s:%u.", path, line);
 415                                 return -EINVAL;
 416                         }
 417
 418                         break;
 419
 420                 case STATE_ALLOW_DENY_INTERFACE:
 421
 422                         if (t == XML_ATTRIBUTE_VALUE) {
 423                                 assert(i);
 424                                 if (i->interface) {
 425                                         log_error("Duplicate interface at %s:%u.", path, line);
 426                                         return -EINVAL;
 427                                 }
 428
 429                                 i->interface = name;
 430                                 name = NULL;
 431                                 state = STATE_ALLOW_DENY;
 432                         } else {
 433                                 log_error("Unexpected token (9) at %s:%u.", path, line);
 434                                 return -EINVAL;
 435                         }
 436
 437                         break;
 438
 439                 case STATE_ALLOW_DENY_MEMBER:
 440
 441                         if (t == XML_ATTRIBUTE_VALUE) {
 442                                 assert(i);
 443                                 if (i->member) {
 444                                         log_error("Duplicate member in %s:%u.", path, line);
 445                                         return -EINVAL;
 446                                 }
 447
 448                                 i->member = name;
 449                                 name = NULL;
 450                                 state = STATE_ALLOW_DENY;
 451                         } else {
 452                                 log_error("Unexpected token (10) in %s:%u.", path, line);
 453                                 return -EINVAL;
 454                         }
 455
 456                         break;
 457
 458                 case STATE_ALLOW_DENY_ERROR:
 459
 460                         if (t == XML_ATTRIBUTE_VALUE) {
 461                                 assert(i);
 462                                 if (i->error) {
 463                                         log_error("Duplicate error in %s:%u.", path, line);
 464                                         return -EINVAL;
 465                                 }
 466
 467                                 i->error = name;
 468                                 name = NULL;
 469                                 state = STATE_ALLOW_DENY;
 470                         } else {
 471                                 log_error("Unexpected token (11) in %s:%u.", path, line);
 472                                 return -EINVAL;
 473                         }
 474
 475                         break;
 476
 477                 case STATE_ALLOW_DENY_PATH:
 478
 479                         if (t == XML_ATTRIBUTE_VALUE) {
 480                                 assert(i);
 481                                 if (i->path) {
 482                                         log_error("Duplicate path in %s:%u.", path, line);
 483                                         return -EINVAL;
 484                                 }
 485
 486                                 i->path = name;
 487                                 name = NULL;
 488                                 state = STATE_ALLOW_DENY;
 489                         } else {
 490                                 log_error("Unexpected token (12) in %s:%u.", path, line);
 491                                 return -EINVAL;
 492                         }
 493
 494                         break;
 495
 496                 case STATE_ALLOW_DENY_MESSAGE_TYPE:
 497
 498                         if (t == XML_ATTRIBUTE_VALUE) {
 499                                 assert(i);
 500
 501                                 if (i->message_type != 0) {
 502                                         log_error("Duplicate message type in %s:%u.", path, line);
 503                                         return -EINVAL;
 504                                 }
 505
 506                                 r = bus_message_type_from_string(name, &i->message_type);
 507                                 if (r < 0) {
 508                                         log_error("Invalid message type in %s:%u.", path, line);
 509                                         return -EINVAL;
 510                                 }
 511
 512                                 state = STATE_ALLOW_DENY;
 513                         } else {
 514                                 log_error("Unexpected token (13) in %s:%u.", path, line);
 515                                 return -EINVAL;
 516                         }
 517
 518                         break;
 519
 520                 case STATE_ALLOW_DENY_NAME:
 521
 522                         if (t == XML_ATTRIBUTE_VALUE) {
 523                                 assert(i);
 524                                 if (i->name) {
 525                                         log_error("Duplicate name in %s:%u.", path, line);
 526                                         return -EINVAL;
 527                                 }
 528
 529                                 switch (i->class) {
 530                                 case POLICY_ITEM_USER:
 531                                         if (!streq(name, "*")) {
 532                                                 const char *u = name;
 533
 534                                                 r = get_user_creds(&u, &i->uid, NULL, NULL, NULL);
 535                                                 if (r < 0)
 536                                                         log_error("Failed to resolve user %s: %s", name, strerror(-r));
 537                                                 else
 538                                                         i->uid_valid = true;
 539                                         }
 540                                         break;
 541                                 case POLICY_ITEM_GROUP:
 542                                         if (!streq(name, "*")) {
 543                                                 const char *g = name;
 544
 545                                                 r = get_group_creds(&g, &i->gid);
 546                                                 if (r < 0)
 547                                                         log_error("Failed to resolve group %s: %s", name, strerror(-r));
 548                                                 else
 549                                                         i->gid_valid = true;
 550                                         }
 551                                         break;
 552                                 default:
 553                                         break;
 554                                 }
 555
 556                                 i->name = name;
 557                                 name = NULL;
 558
 559                                 state = STATE_ALLOW_DENY;
 560                         } else {
 561                                 log_error("Unexpected token (14) in %s:%u.", path, line);
 562                                 return -EINVAL;
 563                         }
 564
 565                         break;
 566
 567                 case STATE_ALLOW_DENY_OTHER_ATTRIBUTE:
 568
 569                         if (t == XML_ATTRIBUTE_VALUE)
 570                                 state = STATE_ALLOW_DENY;
 571                         else {
 572                                 log_error("Unexpected token (15) in %s:%u.", path, line);
 573                                 return -EINVAL;
 574                         }
 575
 576                         break;
 577
 578                 case STATE_OTHER:
 579
 580                         if (t == XML_TAG_OPEN)
 581                                 n_other++;
 582                         else if (t == XML_TAG_CLOSE || t == XML_TAG_CLOSE_EMPTY) {
 583
 584                                 if (n_other == 0)
 585                                         state = STATE_BUSCONFIG;
 586                                 else
 587                                         n_other--;
 588                         }
 589
 590                         break;
 591                 }
 592         }
 593 }
 594
 595 enum {
 596         ALLOW,
 597         DUNNO,
 598         DENY,
 599 };
 600
 601 struct policy_check_filter {
 602         int class;
 603         const struct ucred *ucred;
 604         int message_type;
 605         const char *interface;
 606         const char *path;
 607         union {
 608                 const char *name;
 609                 const char *member;
 610         };
 611         char **names_strv;
 612         Hashmap *names_hash;
 613 };
 614
 615 static int is_permissive(PolicyItem *i) {
 616
 617         assert(i);
 618
 619         return (i->type == POLICY_ITEM_ALLOW) ? ALLOW : DENY;
 620 }
 621
 622 static int check_policy_item(PolicyItem *i, const struct policy_check_filter *filter) {
 623
 624         assert(i);
 625         assert(filter);
 626
 627         switch (i->class) {
 628         case POLICY_ITEM_SEND:
 629         case POLICY_ITEM_RECV:
 630
 631                 if (i->name) {
 632                         if (filter->names_hash && !hashmap_contains(filter->names_hash, i->name))
 633                                 break;
 634
 635                         if (filter->names_strv && !strv_contains(filter->names_strv, i->name))
 636                                 break;
 637                 }
 638
 639                 if ((i->message_type != _POLICY_ITEM_CLASS_UNSET) && (i->message_type != filter->message_type))
 640                         break;
 641
 642                 if (i->path && !streq_ptr(i->path, filter->path))
 643                         break;
 644
 645                 if (i->member && !streq_ptr(i->member, filter->member))
 646                         break;
 647
 648                 if (i->interface && !streq_ptr(i->interface, filter->interface))
 649                         break;
 650
 651                 return is_permissive(i);
 652
 653         case POLICY_ITEM_OWN:
 654                 assert(filter->member);
 655
 656                 if (streq(i->name, "*") || streq(i->name, filter->name))
 657                         return is_permissive(i);
 658                 break;
 659
 660         case POLICY_ITEM_OWN_PREFIX:
 661                 assert(filter->member);
 662
 663                 if (streq(i->name, "*") || startswith(i->name, filter->name))
 664                         return is_permissive(i);
 665                 break;
 666
 667         case POLICY_ITEM_USER:
 668                 assert(filter->ucred);
 669
 670                 if ((streq_ptr(i->name, "*") || (i->uid_valid && i->uid == filter->ucred->uid)))
 671                         return is_permissive(i);
 672                 break;
 673
 674         case POLICY_ITEM_GROUP:
 675                 assert(filter->ucred);
 676
 677                 if ((streq_ptr(i->name, "*") || (i->gid_valid && i->gid == filter->ucred->gid)))
 678                         return is_permissive(i);
 679                 break;
 680
 681         case POLICY_ITEM_IGNORE:
 682         default:
 683                 break;
 684         }
 685
 686         return DUNNO;
 687 }
 688
 689 static int check_policy_items(PolicyItem *items, const struct policy_check_filter *filter) {
 690
 691         PolicyItem *i;
 692         int r, ret = DUNNO;
 693
 694         assert(filter);
 695
 696         /* Check all policies in a set - a broader one might be followed by a more specific one,
 697          * and the order of rules in policy definitions matters */
 698         LIST_FOREACH(items, i, items) {
 699                 if (i->class != filter->class)
 700                         continue;
 701
 702                 r = check_policy_item(i, filter);
 703                 if (r != DUNNO)
 704                         ret = r;
 705         }
 706
 707         return ret;
 708 }
 709
 710 static int policy_check(Policy *p, const struct policy_check_filter *filter) {
 711
 712         PolicyItem *items;
 713         int r;
 714
 715         assert(p);
 716         assert(filter);
 717
 718         /*
 719          * The policy check is implemented by the following logic:
 720          *
 721          * 1. Check mandatory items. If the message matches any of these, it is decisive.
 722          * 2. See if the passed ucred match against the user/group hashmaps. A matching entry is also decisive.
 723          * 3. Consult the defaults if non of the above matched with a more specific rule.
 724          * 4. If the message isn't caught be the defaults either, reject it.
 725          */
 726
 727         r = check_policy_items(p->mandatory_items, filter);
 728         if (r != DUNNO)
 729                 return r;
 730
 731         if (filter->ucred) {
 732                 items = hashmap_get(p->user_items, UINT32_TO_PTR(filter->ucred->uid));
 733                 if (items) {
 734                         r = check_policy_items(items, filter);
 735                         if (r != DUNNO)
 736                                 return r;
 737                 }
 738
 739                 items = hashmap_get(p->group_items, UINT32_TO_PTR(filter->ucred->gid));
 740                 if (items) {
 741                         r = check_policy_items(items, filter);
 742                         if (r != DUNNO)
 743                                 return r;
 744                 }
 745         }
 746
 747         return check_policy_items(p->default_items, filter);
 748 }
 749
 750 bool policy_check_own(Policy *p, const struct ucred *ucred, const char *name) {
 751
 752         struct policy_check_filter filter = {
 753                 .class = POLICY_ITEM_OWN,
 754                 .ucred = ucred,
 755                 .name  = name,
 756         };
 757
 758         return policy_check(p, &filter) == ALLOW;
 759 }
 760
 761 bool policy_check_hello(Policy *p, const struct ucred *ucred) {
 762
 763         struct policy_check_filter filter = {
 764                 .ucred  = ucred,
 765         };
 766         int user, group;
 767
 768         filter.class = POLICY_ITEM_USER;
 769         user = policy_check(p, &filter);
 770         if (user == DENY)
 771                 return false;
 772
 773         filter.class = POLICY_ITEM_GROUP;
 774         group = policy_check(p, &filter);
 775         if (group == DENY)
 776                 return false;
 777
 778         return !(user == DUNNO && group == DUNNO);
 779 }
 780
 781 bool policy_check_recv(Policy *p,
 782                        const struct ucred *ucred,
 783                        Hashmap *names,
 784                        int message_type,
 785                        const char *path,
 786                        const char *interface,
 787                        const char *member) {
 788
 789         struct policy_check_filter filter = {
 790                 .class        = POLICY_ITEM_RECV,
 791                 .ucred        = ucred,
 792                 .names_hash   = names,
 793                 .message_type = message_type,
 794                 .interface    = interface,
 795                 .path         = path,
 796                 .member       = member,
 797         };
 798
 799         return policy_check(p, &filter) == ALLOW;
 800 }
 801
 802 bool policy_check_send(Policy *p,
 803                        const struct ucred *ucred,
 804                        char **names,
 805                        int message_type,
 806                        const char *path,
 807                        const char *interface,
 808                        const char *member) {
 809
 810         struct policy_check_filter filter = {
 811                 .class        = POLICY_ITEM_SEND,
 812                 .ucred        = ucred,
 813                 .names_strv   = names,
 814                 .message_type = message_type,
 815                 .interface    = interface,
 816                 .path         = path,
 817                 .member       = member,
 818         };
 819
 820         return policy_check(p, &filter) == ALLOW;
 821 }
 822
 823 int policy_load(Policy *p, char **files) {
 824         char **i;
 825         int r;
 826
 827         assert(p);
 828
 829         STRV_FOREACH(i, files) {
 830
 831                 r = file_load(p, *i);
 832                 if (r == -EISDIR) {
 833                         _cleanup_strv_free_ char **l = NULL;
 834                         char **j;
 835
 836                         r = conf_files_list(&l, ".conf", NULL, *i, NULL);
 837                         if (r < 0) {
 838                                 log_error("Failed to get configuration file list: %s", strerror(-r));
 839                                 return r;
 840                         }
 841
 842                         STRV_FOREACH(j, l)
 843                                 file_load(p, *j);
 844                 }
 845
 846                 /* We ignore all errors but EISDIR, and just proceed. */
 847         }
 848
 849         return 0;
 850 }
 851
 852 void policy_free(Policy *p) {
 853         PolicyItem *i, *first;
 854
 855         if (!p)
 856                 return;
 857
 858         while ((i = p->default_items)) {
 859                 LIST_REMOVE(items, p->default_items, i);
 860                 policy_item_free(i);
 861         }
 862
 863         while ((i = p->mandatory_items)) {
 864                 LIST_REMOVE(items, p->mandatory_items, i);
 865                 policy_item_free(i);
 866         }
 867
 868         while ((first = hashmap_steal_first(p->user_items))) {
 869
 870                 while ((i = first)) {
 871                         LIST_REMOVE(items, first, i);
 872                         policy_item_free(i);
 873                 }
 874         }
 875
 876         while ((first = hashmap_steal_first(p->group_items))) {
 877
 878                 while ((i = first)) {
 879                         LIST_REMOVE(items, first, i);
 880                         policy_item_free(i);
 881                 }
 882         }
 883
 884         hashmap_free(p->user_items);
 885         hashmap_free(p->group_items);
 886
 887         p->user_items = p->group_items = NULL;
 888 }
 889
 890 static void dump_items(PolicyItem *items, const char *prefix) {
 891
 892         PolicyItem *i;
 893
 894         if (!items)
 895                 return;
 896
 897         if (!prefix)
 898                 prefix = "";
 899
 900         LIST_FOREACH(items, i, items) {
 901
 902                 printf("%sType: %s\n"
 903                        "%sClass: %s\n",
 904                        prefix, policy_item_type_to_string(i->type),
 905                        prefix, policy_item_class_to_string(i->class));
 906
 907                 if (i->interface)
 908                         printf("%sInterface: %s\n",
 909                                prefix, i->interface);
 910
 911                 if (i->member)
 912                         printf("%sMember: %s\n",
 913                                prefix, i->member);
 914
 915                 if (i->error)
 916                         printf("%sError: %s\n",
 917                                prefix, i->error);
 918
 919                 if (i->path)
 920                         printf("%sPath: %s\n",
 921                                prefix, i->path);
 922
 923                 if (i->name)
 924                         printf("%sName: %s\n",
 925                                prefix, i->name);
 926
 927                 if (i->message_type != 0)
 928                         printf("%sMessage Type: %s\n",
 929                                prefix, bus_message_type_to_string(i->message_type));
 930
 931                 if (i->uid_valid) {
 932                         _cleanup_free_ char *user;
 933
 934                         user = uid_to_name(i->uid);
 935
 936                         printf("%sUser: %s (%d)\n",
 937                                prefix, strna(user), i->uid);
 938                 }
 939
 940                 if (i->gid_valid) {
 941                         _cleanup_free_ char *group;
 942
 943                         group = gid_to_name(i->gid);
 944
 945                         printf("%sGroup: %s (%d)\n",
 946                                prefix, strna(group), i->gid);
 947                 }
 948         }
 949 }
 950
 951 static void dump_hashmap_items(Hashmap *h) {
 952         PolicyItem *i;
 953         Iterator j;
 954         void *k;
 955
 956         HASHMAP_FOREACH_KEY(i, k, h, j) {
 957                 printf("\t%s Item for %u:\n", draw_special_char(DRAW_ARROW), PTR_TO_UINT(k));
 958                 dump_items(i, "\t\t");
 959         }
 960 }
 961
 962 void policy_dump(Policy *p) {
 963
 964         printf("%s Default Items:\n", draw_special_char(DRAW_ARROW));
 965         dump_items(p->default_items, "\t");
 966
 967         printf("%s Group Items:\n", draw_special_char(DRAW_ARROW));
 968         dump_hashmap_items(p->group_items);
 969
 970         printf("%s User Items:\n", draw_special_char(DRAW_ARROW));
 971         dump_hashmap_items(p->user_items);
 972
 973         printf("%s Mandatory Items:\n", draw_special_char(DRAW_ARROW));
 974         dump_items(p->mandatory_items, "\t");
 975 }
 976
 977 static const char* const policy_item_type_table[_POLICY_ITEM_TYPE_MAX] = {
 978         [_POLICY_ITEM_TYPE_UNSET] = "unset",
 979         [POLICY_ITEM_ALLOW] = "allow",
 980         [POLICY_ITEM_DENY] = "deny",
 981 };
 982 DEFINE_STRING_TABLE_LOOKUP(policy_item_type, PolicyItemType);
 983
 984 static const char* const policy_item_class_table[_POLICY_ITEM_CLASS_MAX] = {
 985         [_POLICY_ITEM_CLASS_UNSET] = "unset",
 986         [POLICY_ITEM_SEND] = "send",
 987         [POLICY_ITEM_RECV] = "recv",
 988         [POLICY_ITEM_OWN] = "own",
 989         [POLICY_ITEM_OWN_PREFIX] = "own-prefix",
 990         [POLICY_ITEM_USER] = "user",
 991         [POLICY_ITEM_GROUP] = "group",
 992         [POLICY_ITEM_IGNORE] = "ignore",
 993 };
 994 DEFINE_STRING_TABLE_LOOKUP(policy_item_class, PolicyItemClass);