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         const char *member;
 608         char **names_strv;
 609         Hashmap *names_hash;
 610 };
 611
 612 static int is_permissive(PolicyItem *i) {
 613
 614         assert(i);
 615
 616         return (i->type == POLICY_ITEM_ALLOW) ? ALLOW : DENY;
 617 }
 618
 619 static int check_policy_item(PolicyItem *i, const struct policy_check_filter *filter) {
 620
 621         assert(i);
 622         assert(filter);
 623
 624         switch (i->class) {
 625         case POLICY_ITEM_SEND:
 626         case POLICY_ITEM_RECV:
 627
 628                 if (i->name) {
 629                         if (filter->names_hash && !hashmap_contains(filter->names_hash, i->name))
 630                                 break;
 631
 632                         if (filter->names_strv && !strv_contains(filter->names_strv, i->name))
 633                                 break;
 634                 }
 635
 636                 if (i->message_type && (i->message_type != filter->message_type))
 637                         break;
 638
 639                 if (i->path && !streq_ptr(i->path, filter->path))
 640                         break;
 641
 642                 if (i->member && !streq_ptr(i->member, filter->member))
 643                         break;
 644
 645                 if (i->interface && !streq_ptr(i->interface, filter->interface))
 646                         break;
 647
 648                 return is_permissive(i);
 649
 650         case POLICY_ITEM_OWN:
 651                 assert(filter->member);
 652
 653                 if (streq(i->name, filter->member))
 654                         return is_permissive(i);
 655                 break;
 656
 657         case POLICY_ITEM_OWN_PREFIX:
 658                 assert(filter->member);
 659
 660                 if (startswith(i->name, filter->member))
 661                         return is_permissive(i);
 662                 break;
 663
 664         case POLICY_ITEM_USER:
 665                 assert(filter->ucred);
 666
 667                 if ((streq_ptr(i->name, "*") || (i->uid_valid && i->uid == filter->ucred->uid)))
 668                         return is_permissive(i);
 669                 break;
 670
 671         case POLICY_ITEM_GROUP:
 672                 assert(filter->ucred);
 673
 674                 if ((streq_ptr(i->name, "*") || (i->gid_valid && i->gid == filter->ucred->gid)))
 675                         return is_permissive(i);
 676                 break;
 677
 678         case POLICY_ITEM_IGNORE:
 679         default:
 680                 break;
 681         }
 682
 683         return DUNNO;
 684 }
 685
 686 static int check_policy_items(PolicyItem *items, const struct policy_check_filter *filter) {
 687
 688         PolicyItem *i;
 689         int r, ret = DUNNO;
 690
 691         assert(items);
 692         assert(filter);
 693
 694         /* Check all policies in a set - a broader one might be followed by a more specific one,
 695          * and the order of rules in policy definitions matters */
 696         LIST_FOREACH(items, i, items) {
 697                 if (i->class != filter->class)
 698                         continue;
 699
 700                 r = check_policy_item(i, filter);
 701                 if (r != DUNNO)
 702                         ret = r;
 703         }
 704
 705         return ret;
 706 }
 707
 708 static int policy_check(Policy *p, const struct policy_check_filter *filter) {
 709
 710         PolicyItem *items;
 711         int r;
 712
 713         assert(p);
 714         assert(filter);
 715
 716         /*
 717          * The policy check is implemented by the following logic:
 718          *
 719          * 1. Check mandatory items. If the message matches any of these, it is decisive.
 720          * 2. See if the passed ucred match against the user/group hashmaps. A matching entry is also decisive.
 721          * 3. Consult the defaults if non of the above matched with a more specific rule.
 722          * 4. If the message isn't caught be the defaults either, reject it.
 723          */
 724
 725         r = check_policy_items(p->mandatory_items, filter);
 726         if (r != DUNNO)
 727                 return r;
 728
 729         if (filter->ucred) {
 730                 items = hashmap_get(p->user_items, UINT32_TO_PTR(filter->ucred->uid));
 731                 if (items) {
 732                         r = check_policy_items(items, filter);
 733                         if (r != DUNNO)
 734                                 return r;
 735                 }
 736
 737                 items = hashmap_get(p->group_items, UINT32_TO_PTR(filter->ucred->gid));
 738                 if (items) {
 739                         r = check_policy_items(items, filter);
 740                         if (r != DUNNO)
 741                                 return r;
 742                 }
 743         }
 744
 745         return check_policy_items(p->default_items, filter);
 746 }
 747
 748 bool policy_check_own(Policy *p, const struct ucred *ucred, const char *name) {
 749
 750         struct policy_check_filter filter = {
 751                 .class  = POLICY_ITEM_OWN,
 752                 .ucred  = ucred,
 753                 .member = name,
 754         };
 755
 756         return policy_check(p, &filter) == ALLOW;
 757 }
 758
 759 bool policy_check_hello(Policy *p, const struct ucred *ucred) {
 760
 761         struct policy_check_filter filter = {
 762                 .class  = POLICY_ITEM_USER,
 763                 .ucred  = ucred,
 764         };
 765         int user, group;
 766
 767         user = policy_check(p, &filter);
 768         if (user == DENY)
 769                 return false;
 770
 771         filter.class = POLICY_ITEM_GROUP;
 772         group = policy_check(p, &filter);
 773         if (user == DUNNO && group == DUNNO)
 774                 return false;
 775
 776         return !(user == DENY || group == DENY);
 777 }
 778
 779 bool policy_check_recv(Policy *p,
 780                        const struct ucred *ucred,
 781                        Hashmap *names,
 782                        int message_type,
 783                        const char *path,
 784                        const char *interface,
 785                        const char *member) {
 786
 787         struct policy_check_filter filter = {
 788                 .class        = POLICY_ITEM_RECV,
 789                 .ucred        = ucred,
 790                 .names_hash   = names,
 791                 .message_type = message_type,
 792                 .interface    = interface,
 793                 .path         = path,
 794                 .member       = member,
 795         };
 796
 797         return policy_check(p, &filter) == ALLOW;
 798 }
 799
 800 bool policy_check_send(Policy *p,
 801                        const struct ucred *ucred,
 802                        char **names,
 803                        int message_type,
 804                        const char *path,
 805                        const char *interface,
 806                        const char *member) {
 807
 808         struct policy_check_filter filter = {
 809                 .class        = POLICY_ITEM_SEND,
 810                 .ucred        = ucred,
 811                 .names_strv   = names,
 812                 .message_type = message_type,
 813                 .interface    = interface,
 814                 .path         = path,
 815                 .member       = member,
 816         };
 817
 818         return policy_check(p, &filter) == ALLOW;
 819 }
 820
 821 int policy_load(Policy *p, char **files) {
 822         char **i;
 823         int r;
 824
 825         assert(p);
 826
 827         STRV_FOREACH(i, files) {
 828
 829                 r = file_load(p, *i);
 830                 if (r == -EISDIR) {
 831                         _cleanup_strv_free_ char **l = NULL;
 832                         char **j;
 833
 834                         r = conf_files_list(&l, ".conf", NULL, *i, NULL);
 835                         if (r < 0) {
 836                                 log_error("Failed to get configuration file list: %s", strerror(-r));
 837                                 return r;
 838                         }
 839
 840                         STRV_FOREACH(j, l)
 841                                 file_load(p, *j);
 842                 }
 843
 844                 /* We ignore all errors but EISDIR, and just proceed. */
 845         }
 846
 847         return 0;
 848 }
 849
 850 void policy_free(Policy *p) {
 851         PolicyItem *i, *first;
 852
 853         if (!p)
 854                 return;
 855
 856         while ((i = p->default_items)) {
 857                 LIST_REMOVE(items, p->default_items, i);
 858                 policy_item_free(i);
 859         }
 860
 861         while ((i = p->mandatory_items)) {
 862                 LIST_REMOVE(items, p->mandatory_items, i);
 863                 policy_item_free(i);
 864         }
 865
 866         while ((first = hashmap_steal_first(p->user_items))) {
 867
 868                 while ((i = first)) {
 869                         LIST_REMOVE(items, first, i);
 870                         policy_item_free(i);
 871                 }
 872         }
 873
 874         while ((first = hashmap_steal_first(p->group_items))) {
 875
 876                 while ((i = first)) {
 877                         LIST_REMOVE(items, first, i);
 878                         policy_item_free(i);
 879                 }
 880         }
 881
 882         hashmap_free(p->user_items);
 883         hashmap_free(p->group_items);
 884
 885         p->user_items = p->group_items = NULL;
 886 }
 887
 888 static void dump_items(PolicyItem *items, const char *prefix) {
 889
 890         PolicyItem *i;
 891
 892         if (!items)
 893                 return;
 894
 895         if (!prefix)
 896                 prefix = "";
 897
 898         LIST_FOREACH(items, i, items) {
 899
 900                 printf("%sType: %s\n"
 901                        "%sClass: %s\n",
 902                        prefix, policy_item_type_to_string(i->type),
 903                        prefix, policy_item_class_to_string(i->class));
 904
 905                 if (i->interface)
 906                         printf("%sInterface: %s\n",
 907                                prefix, i->interface);
 908
 909                 if (i->member)
 910                         printf("%sMember: %s\n",
 911                                prefix, i->member);
 912
 913                 if (i->error)
 914                         printf("%sError: %s\n",
 915                                prefix, i->error);
 916
 917                 if (i->path)
 918                         printf("%sPath: %s\n",
 919                                prefix, i->path);
 920
 921                 if (i->name)
 922                         printf("%sName: %s\n",
 923                                prefix, i->name);
 924
 925                 if (i->message_type != 0)
 926                         printf("%sMessage Type: %s\n",
 927                                prefix, bus_message_type_to_string(i->message_type));
 928
 929                 if (i->uid_valid) {
 930                         _cleanup_free_ char *user;
 931
 932                         user = uid_to_name(i->uid);
 933
 934                         printf("%sUser: %s (%d)\n",
 935                                prefix, strna(user), i->uid);
 936                 }
 937
 938                 if (i->gid_valid) {
 939                         _cleanup_free_ char *group;
 940
 941                         group = gid_to_name(i->gid);
 942
 943                         printf("%sGroup: %s (%d)\n",
 944                                prefix, strna(group), i->gid);
 945                 }
 946         }
 947 }
 948
 949 static void dump_hashmap_items(Hashmap *h) {
 950         PolicyItem *i;
 951         Iterator j;
 952         void *k;
 953
 954         HASHMAP_FOREACH_KEY(i, k, h, j) {
 955                 printf("\t%s Item for %u:\n", draw_special_char(DRAW_ARROW), PTR_TO_UINT(k));
 956                 dump_items(i, "\t\t");
 957         }
 958 }
 959
 960 void policy_dump(Policy *p) {
 961
 962         printf("%s Default Items:\n", draw_special_char(DRAW_ARROW));
 963         dump_items(p->default_items, "\t");
 964
 965         printf("%s Group Items:\n", draw_special_char(DRAW_ARROW));
 966         dump_hashmap_items(p->group_items);
 967
 968         printf("%s User Items:\n", draw_special_char(DRAW_ARROW));
 969         dump_hashmap_items(p->user_items);
 970
 971         printf("%s Mandatory Items:\n", draw_special_char(DRAW_ARROW));
 972         dump_items(p->mandatory_items, "\t");
 973 }
 974
 975 static const char* const policy_item_type_table[_POLICY_ITEM_TYPE_MAX] = {
 976         [_POLICY_ITEM_TYPE_UNSET] = "unset",
 977         [POLICY_ITEM_ALLOW] = "allow",
 978         [POLICY_ITEM_DENY] = "deny",
 979 };
 980 DEFINE_STRING_TABLE_LOOKUP(policy_item_type, PolicyItemType);
 981
 982 static const char* const policy_item_class_table[_POLICY_ITEM_CLASS_MAX] = {
 983         [_POLICY_ITEM_CLASS_UNSET] = "unset",
 984         [POLICY_ITEM_SEND] = "send",
 985         [POLICY_ITEM_RECV] = "recv",
 986         [POLICY_ITEM_OWN] = "own",
 987         [POLICY_ITEM_OWN_PREFIX] = "own-prefix",
 988         [POLICY_ITEM_USER] = "user",
 989         [POLICY_ITEM_GROUP] = "group",
 990         [POLICY_ITEM_IGNORE] = "ignore",
 991 };
 992 DEFINE_STRING_TABLE_LOOKUP(policy_item_class, PolicyItemClass);