| 1 | /** |
| 2 | * Enhanced Seccomp Filter DB |
| 3 | * |
| 4 | * Copyright (c) 2012,2016 Red Hat <pmoore@redhat.com> |
| 5 | * Author: Paul Moore <paul@paul-moore.com> |
| 6 | */ |
| 7 | |
| 8 | /* |
| 9 | * This library is free software; you can redistribute it and/or modify it |
| 10 | * under the terms of version 2.1 of the GNU Lesser General Public License as |
| 11 | * published by the Free Software Foundation. |
| 12 | * |
| 13 | * This library is distributed in the hope that it will be useful, but WITHOUT |
| 14 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 15 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License |
| 16 | * for more details. |
| 17 | * |
| 18 | * You should have received a copy of the GNU Lesser General Public License |
| 19 | * along with this library; if not, see <http://www.gnu.org/licenses>. |
| 20 | */ |
| 21 | |
| 22 | #include <assert.h> |
| 23 | #include <errno.h> |
| 24 | #include <inttypes.h> |
| 25 | #include <stdlib.h> |
| 26 | #include <string.h> |
| 27 | #include <stdarg.h> |
| 28 | |
| 29 | #include <seccomp.h> |
| 30 | |
| 31 | #include "arch.h" |
| 32 | #include "db.h" |
| 33 | #include "system.h" |
| 34 | |
| 35 | /* state values */ |
| 36 | #define _DB_STA_VALID 0xA1B2C3D4 |
| 37 | #define _DB_STA_FREED 0x1A2B3C4D |
| 38 | |
| 39 | /* the priority field is fairly simple - without any user hints, or in the case |
| 40 | * of a hint "tie", we give higher priority to syscalls with less chain nodes |
| 41 | * (filter is easier to evaluate) */ |
| 42 | #define _DB_PRI_MASK_CHAIN 0x0000FFFF |
| 43 | #define _DB_PRI_MASK_USER 0x00FF0000 |
| 44 | #define _DB_PRI_USER(x) (((x) << 16) & _DB_PRI_MASK_USER) |
| 45 | |
| 46 | /* private structure for tracking the state of the sub-tree "pruning" */ |
| 47 | struct db_prune_state { |
| 48 | bool prefix_exist; |
| 49 | bool prefix_new; |
| 50 | bool matched; |
| 51 | }; |
| 52 | |
| 53 | static unsigned int _db_tree_free(struct db_arg_chain_tree *tree); |
| 54 | |
| 55 | /** |
| 56 | * Do not call this function directly, use _db_tree_free() instead |
| 57 | */ |
| 58 | static unsigned int __db_tree_free(struct db_arg_chain_tree *tree) |
| 59 | { |
| 60 | int cnt; |
| 61 | |
| 62 | if (tree == NULL || --(tree->refcnt) > 0) |
| 63 | return 0; |
| 64 | |
| 65 | /* we assume the caller has ensured that 'tree->lvl_prv == NULL' */ |
| 66 | cnt = __db_tree_free(tree->lvl_nxt); |
| 67 | cnt += _db_tree_free(tree->nxt_t); |
| 68 | cnt += _db_tree_free(tree->nxt_f); |
| 69 | |
| 70 | free(tree); |
| 71 | return cnt + 1; |
| 72 | } |
| 73 | |
| 74 | /** |
| 75 | * Free a syscall filter argument chain tree |
| 76 | * @param tree the argument chain list |
| 77 | * |
| 78 | * This function frees a tree and returns the number of nodes freed. |
| 79 | * |
| 80 | */ |
| 81 | static unsigned int _db_tree_free(struct db_arg_chain_tree *tree) |
| 82 | { |
| 83 | struct db_arg_chain_tree *iter; |
| 84 | |
| 85 | if (tree == NULL) |
| 86 | return 0; |
| 87 | |
| 88 | iter = tree; |
| 89 | while (iter->lvl_prv != NULL) |
| 90 | iter = iter->lvl_prv; |
| 91 | |
| 92 | return __db_tree_free(iter); |
| 93 | } |
| 94 | |
| 95 | /** |
| 96 | * Remove a node from an argument chain tree |
| 97 | * @param tree the pointer to the tree |
| 98 | * @param node the node to remove |
| 99 | * |
| 100 | * This function searches the tree looking for the node and removes it once |
| 101 | * found. Returns the number of nodes freed. |
| 102 | * |
| 103 | */ |
| 104 | static unsigned int _db_tree_remove(struct db_arg_chain_tree **tree, |
| 105 | struct db_arg_chain_tree *node) |
| 106 | { |
| 107 | int cnt = 0; |
| 108 | struct db_arg_chain_tree *c_iter; |
| 109 | |
| 110 | if (tree == NULL || *tree == NULL || node == NULL) |
| 111 | return 0; |
| 112 | |
| 113 | c_iter = *tree; |
| 114 | while (c_iter->lvl_prv != NULL) |
| 115 | c_iter = c_iter->lvl_prv; |
| 116 | |
| 117 | do { |
| 118 | if (c_iter == node || db_chain_zombie(c_iter)) { |
| 119 | /* remove from the tree */ |
| 120 | if (c_iter == *tree) { |
| 121 | if (c_iter->lvl_prv != NULL) |
| 122 | *tree = c_iter->lvl_prv; |
| 123 | else |
| 124 | *tree = c_iter->lvl_nxt; |
| 125 | } |
| 126 | if (c_iter->lvl_prv != NULL) |
| 127 | c_iter->lvl_prv->lvl_nxt = c_iter->lvl_nxt; |
| 128 | if (c_iter->lvl_nxt != NULL) |
| 129 | c_iter->lvl_nxt->lvl_prv = c_iter->lvl_prv; |
| 130 | |
| 131 | /* free and return */ |
| 132 | c_iter->lvl_prv = NULL; |
| 133 | c_iter->lvl_nxt = NULL; |
| 134 | cnt += _db_tree_free(c_iter); |
| 135 | return cnt; |
| 136 | } |
| 137 | |
| 138 | /* check the true/false sub-trees */ |
| 139 | cnt += _db_tree_remove(&(c_iter->nxt_t), node); |
| 140 | cnt += _db_tree_remove(&(c_iter->nxt_f), node); |
| 141 | |
| 142 | c_iter = c_iter->lvl_nxt; |
| 143 | } while (c_iter != NULL); |
| 144 | |
| 145 | return cnt; |
| 146 | } |
| 147 | |
| 148 | /** |
| 149 | * Traverse a tree checking the action values |
| 150 | * @param tree the pointer to the tree |
| 151 | * @param action the action |
| 152 | * |
| 153 | * Traverse the tree inspecting each action to see if it matches the given |
| 154 | * action. Returns zero if all actions match the given action, negative values |
| 155 | * on failure. |
| 156 | * |
| 157 | */ |
| 158 | static int _db_tree_act_check(struct db_arg_chain_tree *tree, uint32_t action) |
| 159 | { |
| 160 | int rc; |
| 161 | struct db_arg_chain_tree *c_iter; |
| 162 | |
| 163 | if (tree == NULL) |
| 164 | return 0; |
| 165 | |
| 166 | c_iter = tree; |
| 167 | while (c_iter->lvl_prv != NULL) |
| 168 | c_iter = c_iter->lvl_prv; |
| 169 | |
| 170 | do { |
| 171 | if (c_iter->act_t_flg && c_iter->act_t != action) |
| 172 | return -EEXIST; |
| 173 | if (c_iter->act_f_flg && c_iter->act_f != action) |
| 174 | return -EEXIST; |
| 175 | |
| 176 | rc = _db_tree_act_check(c_iter->nxt_t, action); |
| 177 | if (rc < 0) |
| 178 | return rc; |
| 179 | rc = _db_tree_act_check(c_iter->nxt_f, action); |
| 180 | if (rc < 0) |
| 181 | return rc; |
| 182 | |
| 183 | c_iter = c_iter->lvl_nxt; |
| 184 | } while (c_iter != NULL); |
| 185 | |
| 186 | return 0; |
| 187 | } |
| 188 | |
| 189 | /** |
| 190 | * Checks for a sub-tree match in an existing tree and prunes the tree |
| 191 | * @param prev the head of the existing tree or sub-tree |
| 192 | * @param existing the starting point into the existing tree |
| 193 | * @param new pointer to the new tree |
| 194 | * @param state pointer to the pruning state |
| 195 | * |
| 196 | * This function searches the existing and new trees trying to prune each to |
| 197 | * eliminate redundancy. Returns the number of nodes removed from the tree on |
| 198 | * success, zero if no changes were made, and negative values if the new tree |
| 199 | * should be discarded. |
| 200 | * |
| 201 | */ |
| 202 | static int _db_tree_sub_prune(struct db_arg_chain_tree **prev, |
| 203 | struct db_arg_chain_tree *existing, |
| 204 | struct db_arg_chain_tree *new, |
| 205 | struct db_prune_state *state) |
| 206 | { |
| 207 | int rc = 0; |
| 208 | int rc_tmp; |
| 209 | struct db_arg_chain_tree *ec_iter; |
| 210 | struct db_arg_chain_tree *ec_iter_tmp; |
| 211 | struct db_arg_chain_tree *c_iter; |
| 212 | struct db_prune_state state_new; |
| 213 | |
| 214 | if (!state || !existing || !new) |
| 215 | return 0; |
| 216 | |
| 217 | ec_iter = existing; |
| 218 | c_iter = new; |
| 219 | do { |
| 220 | if (db_chain_eq(ec_iter, c_iter)) { |
| 221 | /* equal */ |
| 222 | |
| 223 | if (db_chain_leaf(c_iter)) { |
| 224 | /* leaf */ |
| 225 | if (db_chain_eq_result(ec_iter, c_iter)) { |
| 226 | /* identical results */ |
| 227 | if (prev != NULL) |
| 228 | return _db_tree_remove(prev, |
| 229 | ec_iter); |
| 230 | else |
| 231 | return -1; |
| 232 | } |
| 233 | if (c_iter->act_t_flg && ec_iter->nxt_t) { |
| 234 | /* new is shorter (true) */ |
| 235 | if (prev == NULL) |
| 236 | return -1; |
| 237 | rc += _db_tree_remove(&(ec_iter->nxt_t), |
| 238 | ec_iter->nxt_t); |
| 239 | ec_iter->act_t = c_iter->act_t; |
| 240 | ec_iter->act_t_flg = true; |
| 241 | } |
| 242 | if (c_iter->act_f_flg && ec_iter->nxt_f) { |
| 243 | /* new is shorter (false) */ |
| 244 | if (prev == NULL) |
| 245 | return -1; |
| 246 | rc += _db_tree_remove(&(ec_iter->nxt_f), |
| 247 | ec_iter->nxt_f); |
| 248 | ec_iter->act_f = c_iter->act_f; |
| 249 | ec_iter->act_f_flg = true; |
| 250 | } |
| 251 | |
| 252 | return rc; |
| 253 | } |
| 254 | |
| 255 | if (c_iter->nxt_t && ec_iter->act_t_flg) |
| 256 | /* existing is shorter (true) */ |
| 257 | return -1; |
| 258 | if (c_iter->nxt_f && ec_iter->act_f_flg) |
| 259 | /* existing is shorter (false) */ |
| 260 | return -1; |
| 261 | |
| 262 | if (c_iter->nxt_t) { |
| 263 | state_new = *state; |
| 264 | state_new.matched = true; |
| 265 | rc_tmp = _db_tree_sub_prune((prev ? |
| 266 | &ec_iter : NULL), |
| 267 | ec_iter->nxt_t, |
| 268 | c_iter->nxt_t, |
| 269 | &state_new); |
| 270 | rc += (rc_tmp > 0 ? rc_tmp : 0); |
| 271 | if (state->prefix_new && rc_tmp < 0) |
| 272 | return (rc > 0 ? rc : rc_tmp); |
| 273 | } |
| 274 | if (c_iter->nxt_f) { |
| 275 | state_new = *state; |
| 276 | state_new.matched = true; |
| 277 | rc_tmp = _db_tree_sub_prune((prev ? |
| 278 | &ec_iter : NULL), |
| 279 | ec_iter->nxt_f, |
| 280 | c_iter->nxt_f, |
| 281 | &state_new); |
| 282 | rc += (rc_tmp > 0 ? rc_tmp : 0); |
| 283 | if (state->prefix_new && rc_tmp < 0) |
| 284 | return (rc > 0 ? rc : rc_tmp); |
| 285 | } |
| 286 | } else if (db_chain_lt(ec_iter, c_iter)) { |
| 287 | /* less than */ |
| 288 | if (state->matched || state->prefix_new) |
| 289 | goto next; |
| 290 | state_new = *state; |
| 291 | state_new.prefix_exist = true; |
| 292 | |
| 293 | if (ec_iter->nxt_t) { |
| 294 | rc_tmp = _db_tree_sub_prune((prev ? |
| 295 | &ec_iter : NULL), |
| 296 | ec_iter->nxt_t, |
| 297 | c_iter, |
| 298 | &state_new); |
| 299 | rc += (rc_tmp > 0 ? rc_tmp : 0); |
| 300 | } |
| 301 | if (ec_iter->nxt_f) { |
| 302 | rc_tmp = _db_tree_sub_prune((prev ? |
| 303 | &ec_iter : NULL), |
| 304 | ec_iter->nxt_f, |
| 305 | c_iter, |
| 306 | &state_new); |
| 307 | rc += (rc_tmp > 0 ? rc_tmp : 0); |
| 308 | } |
| 309 | } else if (db_chain_gt(ec_iter, c_iter)) { |
| 310 | /* greater than */ |
| 311 | if (state->matched || state->prefix_exist) |
| 312 | goto next; |
| 313 | state_new = *state; |
| 314 | state_new.prefix_new = true; |
| 315 | |
| 316 | if (c_iter->nxt_t) { |
| 317 | rc_tmp = _db_tree_sub_prune(NULL, |
| 318 | ec_iter, |
| 319 | c_iter->nxt_t, |
| 320 | &state_new); |
| 321 | rc += (rc_tmp > 0 ? rc_tmp : 0); |
| 322 | if (rc_tmp < 0) |
| 323 | return (rc > 0 ? rc : rc_tmp); |
| 324 | } |
| 325 | if (c_iter->nxt_f) { |
| 326 | rc_tmp = _db_tree_sub_prune(NULL, |
| 327 | ec_iter, |
| 328 | c_iter->nxt_f, |
| 329 | &state_new); |
| 330 | rc += (rc_tmp > 0 ? rc_tmp : 0); |
| 331 | if (rc_tmp < 0) |
| 332 | return (rc > 0 ? rc : rc_tmp); |
| 333 | } |
| 334 | } |
| 335 | |
| 336 | next: |
| 337 | /* re-check current node and advance to the next node */ |
| 338 | if (db_chain_zombie(ec_iter)) { |
| 339 | ec_iter_tmp = ec_iter->lvl_nxt; |
| 340 | rc += _db_tree_remove(prev, ec_iter); |
| 341 | ec_iter = ec_iter_tmp; |
| 342 | } else |
| 343 | ec_iter = ec_iter->lvl_nxt; |
| 344 | } while (ec_iter); |
| 345 | |
| 346 | return rc; |
| 347 | } |
| 348 | |
| 349 | /** |
| 350 | * Free and reset the seccomp filter DB |
| 351 | * @param db the seccomp filter DB |
| 352 | * |
| 353 | * This function frees any existing filters and resets the filter DB to a |
| 354 | * default state; only the DB architecture is preserved. |
| 355 | * |
| 356 | */ |
| 357 | static void _db_reset(struct db_filter *db) |
| 358 | { |
| 359 | struct db_sys_list *s_iter; |
| 360 | struct db_api_rule_list *r_iter; |
| 361 | |
| 362 | if (db == NULL) |
| 363 | return; |
| 364 | |
| 365 | /* free any filters */ |
| 366 | if (db->syscalls != NULL) { |
| 367 | s_iter = db->syscalls; |
| 368 | while (s_iter != NULL) { |
| 369 | db->syscalls = s_iter->next; |
| 370 | _db_tree_free(s_iter->chains); |
| 371 | free(s_iter); |
| 372 | s_iter = db->syscalls; |
| 373 | } |
| 374 | db->syscalls = NULL; |
| 375 | } |
| 376 | |
| 377 | /* free any rules */ |
| 378 | if (db->rules != NULL) { |
| 379 | /* split the loop first then loop and free */ |
| 380 | db->rules->prev->next = NULL; |
| 381 | r_iter = db->rules; |
| 382 | while (r_iter != NULL) { |
| 383 | db->rules = r_iter->next; |
| 384 | free(r_iter->args); |
| 385 | free(r_iter); |
| 386 | r_iter = db->rules; |
| 387 | } |
| 388 | db->rules = NULL; |
| 389 | } |
| 390 | } |
| 391 | |
| 392 | /** |
| 393 | * Intitalize a seccomp filter DB |
| 394 | * @param arch the architecture definition |
| 395 | * |
| 396 | * This function initializes a seccomp filter DB and readies it for use. |
| 397 | * Returns a pointer to the DB on success, NULL on failure. |
| 398 | * |
| 399 | */ |
| 400 | static struct db_filter *_db_init(const struct arch_def *arch) |
| 401 | { |
| 402 | struct db_filter *db; |
| 403 | |
| 404 | db = malloc(sizeof(*db)); |
| 405 | if (db == NULL) |
| 406 | return NULL; |
| 407 | |
| 408 | /* clear the buffer for the first time and set the arch */ |
| 409 | memset(db, 0, sizeof(*db)); |
| 410 | db->arch = arch; |
| 411 | |
| 412 | /* reset the DB to a known state */ |
| 413 | _db_reset(db); |
| 414 | |
| 415 | return db; |
| 416 | } |
| 417 | |
| 418 | /** |
| 419 | * Destroy a seccomp filter DB |
| 420 | * @param db the seccomp filter DB |
| 421 | * |
| 422 | * This function destroys a seccomp filter DB. After calling this function, |
| 423 | * the filter should no longer be referenced. |
| 424 | * |
| 425 | */ |
| 426 | static void _db_release(struct db_filter *db) |
| 427 | { |
| 428 | if (db == NULL) |
| 429 | return; |
| 430 | |
| 431 | /* free and reset the DB */ |
| 432 | _db_reset(db); |
| 433 | free(db); |
| 434 | } |
| 435 | |
| 436 | /** |
| 437 | * Destroy a seccomp filter snapshot |
| 438 | * @param snap the seccomp filter snapshot |
| 439 | * |
| 440 | * This function destroys a seccomp filter snapshot. After calling this |
| 441 | * function, the snapshot should no longer be referenced. |
| 442 | * |
| 443 | */ |
| 444 | static void _db_snap_release(struct db_filter_snap *snap) |
| 445 | { |
| 446 | unsigned int iter; |
| 447 | |
| 448 | if (snap->filter_cnt > 0) { |
| 449 | for (iter = 0; iter < snap->filter_cnt; iter++) { |
| 450 | if (snap->filters[iter]) |
| 451 | _db_release(snap->filters[iter]); |
| 452 | } |
| 453 | free(snap->filters); |
| 454 | } |
| 455 | free(snap); |
| 456 | } |
| 457 | |
| 458 | /** |
| 459 | * Update the user specified portion of the syscall priority |
| 460 | * @param db the seccomp filter db |
| 461 | * @param syscall the syscall number |
| 462 | * @param priority the syscall priority |
| 463 | * |
| 464 | * This function sets, or updates, the syscall priority; the highest priority |
| 465 | * value between the existing and specified value becomes the new syscall |
| 466 | * priority. If the syscall entry does not already exist, a new phantom |
| 467 | * syscall entry is created as a placeholder. Returns zero on success, |
| 468 | * negative values on failure. |
| 469 | * |
| 470 | */ |
| 471 | static int _db_syscall_priority(struct db_filter *db, |
| 472 | int syscall, uint8_t priority) |
| 473 | { |
| 474 | unsigned int sys_pri = _DB_PRI_USER(priority); |
| 475 | struct db_sys_list *s_new, *s_iter, *s_prev = NULL; |
| 476 | |
| 477 | assert(db != NULL); |
| 478 | |
| 479 | s_iter = db->syscalls; |
| 480 | while (s_iter != NULL && s_iter->num < syscall) { |
| 481 | s_prev = s_iter; |
| 482 | s_iter = s_iter->next; |
| 483 | } |
| 484 | |
| 485 | /* matched an existing syscall entry */ |
| 486 | if (s_iter != NULL && s_iter->num == syscall) { |
| 487 | if (sys_pri > (s_iter->priority & _DB_PRI_MASK_USER)) { |
| 488 | s_iter->priority &= (~_DB_PRI_MASK_USER); |
| 489 | s_iter->priority |= sys_pri; |
| 490 | } |
| 491 | return 0; |
| 492 | } |
| 493 | |
| 494 | /* no existing syscall entry - create a phantom entry */ |
| 495 | s_new = malloc(sizeof(*s_new)); |
| 496 | if (s_new == NULL) |
| 497 | return -ENOMEM; |
| 498 | memset(s_new, 0, sizeof(*s_new)); |
| 499 | s_new->num = syscall; |
| 500 | s_new->priority = sys_pri; |
| 501 | s_new->valid = false; |
| 502 | |
| 503 | /* add it before s_iter */ |
| 504 | if (s_prev != NULL) { |
| 505 | s_new->next = s_prev->next; |
| 506 | s_prev->next = s_new; |
| 507 | } else { |
| 508 | s_new->next = db->syscalls; |
| 509 | db->syscalls = s_new; |
| 510 | } |
| 511 | |
| 512 | return 0; |
| 513 | } |
| 514 | |
| 515 | /** |
| 516 | * Free and reset the seccomp filter collection |
| 517 | * @param col the seccomp filter collection |
| 518 | * @param def_action the default filter action |
| 519 | * |
| 520 | * This function frees any existing filter DBs and resets the collection to a |
| 521 | * default state. In the case of failure the filter collection may be in an |
| 522 | * unknown state and should be released. Returns zero on success, negative |
| 523 | * values on failure. |
| 524 | * |
| 525 | */ |
| 526 | int db_col_reset(struct db_filter_col *col, uint32_t def_action) |
| 527 | { |
| 528 | unsigned int iter; |
| 529 | struct db_filter *db; |
| 530 | struct db_filter_snap *snap; |
| 531 | |
| 532 | if (col == NULL) |
| 533 | return -EINVAL; |
| 534 | |
| 535 | /* free any filters */ |
| 536 | for (iter = 0; iter < col->filter_cnt; iter++) |
| 537 | _db_release(col->filters[iter]); |
| 538 | col->filter_cnt = 0; |
| 539 | if (col->filters) |
| 540 | free(col->filters); |
| 541 | col->filters = NULL; |
| 542 | |
| 543 | /* set the endianess to undefined */ |
| 544 | col->endian = 0; |
| 545 | |
| 546 | /* set the default attribute values */ |
| 547 | col->attr.act_default = def_action; |
| 548 | col->attr.act_badarch = SCMP_ACT_KILL; |
| 549 | col->attr.nnp_enable = 1; |
| 550 | col->attr.tsync_enable = 0; |
| 551 | |
| 552 | /* set the state */ |
| 553 | col->state = _DB_STA_VALID; |
| 554 | |
| 555 | /* reset the initial db */ |
| 556 | db = _db_init(arch_def_native); |
| 557 | if (db == NULL) |
| 558 | return -ENOMEM; |
| 559 | if (db_col_db_add(col, db) < 0) { |
| 560 | _db_release(db); |
| 561 | return -ENOMEM; |
| 562 | } |
| 563 | |
| 564 | /* reset the transactions */ |
| 565 | while (col->snapshots) { |
| 566 | snap = col->snapshots; |
| 567 | col->snapshots = snap->next; |
| 568 | for (iter = 0; iter < snap->filter_cnt; iter++) |
| 569 | _db_release(snap->filters[iter]); |
| 570 | free(snap->filters); |
| 571 | free(snap); |
| 572 | } |
| 573 | |
| 574 | return 0; |
| 575 | } |
| 576 | |
| 577 | /** |
| 578 | * Intitalize a seccomp filter collection |
| 579 | * @param def_action the default filter action |
| 580 | * |
| 581 | * This function initializes a seccomp filter collection and readies it for |
| 582 | * use. Returns a pointer to the collection on success, NULL on failure. |
| 583 | * |
| 584 | */ |
| 585 | struct db_filter_col *db_col_init(uint32_t def_action) |
| 586 | { |
| 587 | struct db_filter_col *col; |
| 588 | |
| 589 | col = malloc(sizeof(*col)); |
| 590 | if (col == NULL) |
| 591 | return NULL; |
| 592 | |
| 593 | /* clear the buffer for the first time */ |
| 594 | memset(col, 0, sizeof(*col)); |
| 595 | |
| 596 | /* reset the DB to a known state */ |
| 597 | if (db_col_reset(col, def_action) < 0) |
| 598 | goto init_failure; |
| 599 | |
| 600 | return col; |
| 601 | |
| 602 | init_failure: |
| 603 | db_col_release(col); |
| 604 | return NULL; |
| 605 | } |
| 606 | |
| 607 | /** |
| 608 | * Destroy a seccomp filter collection |
| 609 | * @param col the seccomp filter collection |
| 610 | * |
| 611 | * This function destroys a seccomp filter collection. After calling this |
| 612 | * function, the filter should no longer be referenced. |
| 613 | * |
| 614 | */ |
| 615 | void db_col_release(struct db_filter_col *col) |
| 616 | { |
| 617 | unsigned int iter; |
| 618 | |
| 619 | if (col == NULL) |
| 620 | return; |
| 621 | |
| 622 | /* set the state, just in case */ |
| 623 | col->state = _DB_STA_FREED; |
| 624 | |
| 625 | /* free any filters */ |
| 626 | for (iter = 0; iter < col->filter_cnt; iter++) |
| 627 | _db_release(col->filters[iter]); |
| 628 | col->filter_cnt = 0; |
| 629 | if (col->filters) |
| 630 | free(col->filters); |
| 631 | col->filters = NULL; |
| 632 | |
| 633 | /* free the collection */ |
| 634 | free(col); |
| 635 | } |
| 636 | |
| 637 | /** |
| 638 | * Validate the seccomp action |
| 639 | * @param action the seccomp action |
| 640 | * |
| 641 | * Verify that the given action is a valid seccomp action; return zero if |
| 642 | * valid, -EINVAL if invalid. |
| 643 | */ |
| 644 | int db_action_valid(uint32_t action) |
| 645 | { |
| 646 | if (action == SCMP_ACT_KILL) |
| 647 | return 0; |
| 648 | else if (action == SCMP_ACT_TRAP) |
| 649 | return 0; |
| 650 | else if ((action == SCMP_ACT_ERRNO(action & 0x0000ffff)) && |
| 651 | ((action & 0x0000ffff) < MAX_ERRNO)) |
| 652 | return 0; |
| 653 | else if (action == SCMP_ACT_TRACE(action & 0x0000ffff)) |
| 654 | return 0; |
| 655 | else if (action == SCMP_ACT_ALLOW) |
| 656 | return 0; |
| 657 | |
| 658 | return -EINVAL; |
| 659 | } |
| 660 | |
| 661 | /** |
| 662 | * Validate a filter collection |
| 663 | * @param col the seccomp filter collection |
| 664 | * |
| 665 | * This function validates a seccomp filter collection. Returns zero if the |
| 666 | * collection is valid, negative values on failure. |
| 667 | * |
| 668 | */ |
| 669 | int db_col_valid(struct db_filter_col *col) |
| 670 | { |
| 671 | if (col != NULL && col->state == _DB_STA_VALID && col->filter_cnt > 0) |
| 672 | return 0; |
| 673 | return -EINVAL; |
| 674 | } |
| 675 | |
| 676 | /** |
| 677 | * Merge two filter collections |
| 678 | * @param col_dst the destination filter collection |
| 679 | * @param col_src the source filter collection |
| 680 | * |
| 681 | * This function merges two filter collections into the given destination |
| 682 | * collection. The source filter collection is no longer valid if the function |
| 683 | * returns successfully. Returns zero on success, negative values on failure. |
| 684 | * |
| 685 | */ |
| 686 | int db_col_merge(struct db_filter_col *col_dst, struct db_filter_col *col_src) |
| 687 | { |
| 688 | unsigned int iter_a, iter_b; |
| 689 | struct db_filter **dbs; |
| 690 | |
| 691 | /* verify that the endianess is a match */ |
| 692 | if (col_dst->endian != col_src->endian) |
| 693 | return -EEXIST; |
| 694 | |
| 695 | /* make sure we don't have any arch/filter collisions */ |
| 696 | for (iter_a = 0; iter_a < col_dst->filter_cnt; iter_a++) { |
| 697 | for (iter_b = 0; iter_b < col_src->filter_cnt; iter_b++) { |
| 698 | if (col_dst->filters[iter_a]->arch->token == |
| 699 | col_src->filters[iter_b]->arch->token) |
| 700 | return -EEXIST; |
| 701 | } |
| 702 | } |
| 703 | |
| 704 | /* expand the destination */ |
| 705 | dbs = realloc(col_dst->filters, |
| 706 | sizeof(struct db_filter *) * |
| 707 | (col_dst->filter_cnt + col_src->filter_cnt)); |
| 708 | if (dbs == NULL) |
| 709 | return -ENOMEM; |
| 710 | col_dst->filters = dbs; |
| 711 | |
| 712 | /* transfer the architecture filters */ |
| 713 | for (iter_a = col_dst->filter_cnt, iter_b = 0; |
| 714 | iter_b < col_src->filter_cnt; iter_a++, iter_b++) { |
| 715 | col_dst->filters[iter_a] = col_src->filters[iter_b]; |
| 716 | col_dst->filter_cnt++; |
| 717 | } |
| 718 | |
| 719 | /* free the source */ |
| 720 | col_src->filter_cnt = 0; |
| 721 | db_col_release(col_src); |
| 722 | |
| 723 | return 0; |
| 724 | } |
| 725 | |
| 726 | /** |
| 727 | * Check to see if an architecture filter exists in the filter collection |
| 728 | * @param col the seccomp filter collection |
| 729 | * @param arch_token the architecture token |
| 730 | * |
| 731 | * Iterate through the given filter collection checking to see if a filter |
| 732 | * exists for the specified architecture. Returns -EEXIST if a filter is found, |
| 733 | * zero if a matching filter does not exist. |
| 734 | * |
| 735 | */ |
| 736 | int db_col_arch_exist(struct db_filter_col *col, uint32_t arch_token) |
| 737 | { |
| 738 | unsigned int iter; |
| 739 | |
| 740 | for (iter = 0; iter < col->filter_cnt; iter++) |
| 741 | if (col->filters[iter]->arch->token == arch_token) |
| 742 | return -EEXIST; |
| 743 | |
| 744 | return 0; |
| 745 | } |
| 746 | |
| 747 | /** |
| 748 | * Get a filter attribute |
| 749 | * @param col the seccomp filter collection |
| 750 | * @param attr the filter attribute |
| 751 | * @param value the filter attribute value |
| 752 | * |
| 753 | * Get the requested filter attribute and provide it via @value. Returns zero |
| 754 | * on success, negative values on failure. |
| 755 | * |
| 756 | */ |
| 757 | int db_col_attr_get(const struct db_filter_col *col, |
| 758 | enum scmp_filter_attr attr, uint32_t *value) |
| 759 | { |
| 760 | int rc = 0; |
| 761 | |
| 762 | switch (attr) { |
| 763 | case SCMP_FLTATR_ACT_DEFAULT: |
| 764 | *value = col->attr.act_default; |
| 765 | break; |
| 766 | case SCMP_FLTATR_ACT_BADARCH: |
| 767 | *value = col->attr.act_badarch; |
| 768 | break; |
| 769 | case SCMP_FLTATR_CTL_NNP: |
| 770 | *value = col->attr.nnp_enable; |
| 771 | break; |
| 772 | case SCMP_FLTATR_CTL_TSYNC: |
| 773 | *value = col->attr.tsync_enable; |
| 774 | break; |
| 775 | default: |
| 776 | rc = -EEXIST; |
| 777 | break; |
| 778 | } |
| 779 | |
| 780 | return rc; |
| 781 | } |
| 782 | |
| 783 | /** |
| 784 | * Set a filter attribute |
| 785 | * @param col the seccomp filter collection |
| 786 | * @param attr the filter attribute |
| 787 | * @param value the filter attribute value |
| 788 | * |
| 789 | * Set the requested filter attribute with the given value. Returns zero on |
| 790 | * success, negative values on failure. |
| 791 | * |
| 792 | */ |
| 793 | int db_col_attr_set(struct db_filter_col *col, |
| 794 | enum scmp_filter_attr attr, uint32_t value) |
| 795 | { |
| 796 | int rc = 0; |
| 797 | |
| 798 | switch (attr) { |
| 799 | case SCMP_FLTATR_ACT_DEFAULT: |
| 800 | /* read only */ |
| 801 | return -EACCES; |
| 802 | break; |
| 803 | case SCMP_FLTATR_ACT_BADARCH: |
| 804 | if (db_action_valid(value) == 0) |
| 805 | col->attr.act_badarch = value; |
| 806 | else |
| 807 | return -EINVAL; |
| 808 | break; |
| 809 | case SCMP_FLTATR_CTL_NNP: |
| 810 | col->attr.nnp_enable = (value ? 1 : 0); |
| 811 | break; |
| 812 | case SCMP_FLTATR_CTL_TSYNC: |
| 813 | rc = sys_chk_seccomp_flag(SECCOMP_FILTER_FLAG_TSYNC); |
| 814 | if (rc == 1) { |
| 815 | /* supported */ |
| 816 | rc = 0; |
| 817 | col->attr.tsync_enable = (value ? 1 : 0); |
| 818 | } else if (rc == 0) |
| 819 | /* unsupported */ |
| 820 | rc = -EOPNOTSUPP; |
| 821 | break; |
| 822 | default: |
| 823 | rc = -EEXIST; |
| 824 | break; |
| 825 | } |
| 826 | |
| 827 | return rc; |
| 828 | } |
| 829 | |
| 830 | /** |
| 831 | * Add a new architecture filter to a filter collection |
| 832 | * @param col the seccomp filter collection |
| 833 | * @param arch the architecture |
| 834 | * |
| 835 | * This function adds a new architecture filter DB to an existing seccomp |
| 836 | * filter collection assuming there isn't a filter DB already present with the |
| 837 | * same architecture. Returns zero on success, negative values on failure. |
| 838 | * |
| 839 | */ |
| 840 | int db_col_db_new(struct db_filter_col *col, const struct arch_def *arch) |
| 841 | { |
| 842 | int rc; |
| 843 | struct db_filter *db; |
| 844 | |
| 845 | db = _db_init(arch); |
| 846 | if (db == NULL) |
| 847 | return -ENOMEM; |
| 848 | rc = db_col_db_add(col, db); |
| 849 | if (rc < 0) |
| 850 | _db_release(db); |
| 851 | |
| 852 | return rc; |
| 853 | } |
| 854 | |
| 855 | /** |
| 856 | * Add a new filter DB to a filter collection |
| 857 | * @param col the seccomp filter collection |
| 858 | * @param db the seccomp filter DB |
| 859 | * |
| 860 | * This function adds an existing seccomp filter DB to an existing seccomp |
| 861 | * filter collection assuming there isn't a filter DB already present with the |
| 862 | * same architecture. Returns zero on success, negative values on failure. |
| 863 | * |
| 864 | */ |
| 865 | int db_col_db_add(struct db_filter_col *col, struct db_filter *db) |
| 866 | { |
| 867 | struct db_filter **dbs; |
| 868 | |
| 869 | if (col->endian != 0 && col->endian != db->arch->endian) |
| 870 | return -EEXIST; |
| 871 | |
| 872 | if (db_col_arch_exist(col, db->arch->token)) |
| 873 | return -EEXIST; |
| 874 | |
| 875 | dbs = realloc(col->filters, |
| 876 | sizeof(struct db_filter *) * (col->filter_cnt + 1)); |
| 877 | if (dbs == NULL) |
| 878 | return -ENOMEM; |
| 879 | col->filters = dbs; |
| 880 | col->filter_cnt++; |
| 881 | col->filters[col->filter_cnt - 1] = db; |
| 882 | if (col->endian == 0) |
| 883 | col->endian = db->arch->endian; |
| 884 | |
| 885 | return 0; |
| 886 | } |
| 887 | |
| 888 | /** |
| 889 | * Remove a filter DB from a filter collection |
| 890 | * @param col the seccomp filter collection |
| 891 | * @param arch_token the architecture token |
| 892 | * |
| 893 | * This function removes an existing seccomp filter DB from an existing seccomp |
| 894 | * filter collection. Returns zero on success, negative values on failure. |
| 895 | * |
| 896 | */ |
| 897 | int db_col_db_remove(struct db_filter_col *col, uint32_t arch_token) |
| 898 | { |
| 899 | unsigned int iter; |
| 900 | unsigned int found; |
| 901 | struct db_filter **dbs; |
| 902 | |
| 903 | if ((col->filter_cnt <= 0) || (db_col_arch_exist(col, arch_token) == 0)) |
| 904 | return -EINVAL; |
| 905 | |
| 906 | for (found = 0, iter = 0; iter < col->filter_cnt; iter++) { |
| 907 | if (found) |
| 908 | col->filters[iter - 1] = col->filters[iter]; |
| 909 | else if (col->filters[iter]->arch->token == arch_token) { |
| 910 | _db_release(col->filters[iter]); |
| 911 | found = 1; |
| 912 | } |
| 913 | } |
| 914 | col->filters[--col->filter_cnt] = NULL; |
| 915 | |
| 916 | if (col->filter_cnt > 0) { |
| 917 | /* NOTE: if we can't do the realloc it isn't fatal, we just |
| 918 | * have some extra space allocated */ |
| 919 | dbs = realloc(col->filters, |
| 920 | sizeof(struct db_filter *) * col->filter_cnt); |
| 921 | if (dbs != NULL) |
| 922 | col->filters = dbs; |
| 923 | } else { |
| 924 | /* this was the last filter so free all the associated memory |
| 925 | * and reset the endian token */ |
| 926 | free(col->filters); |
| 927 | col->filters = NULL; |
| 928 | col->endian = 0; |
| 929 | } |
| 930 | |
| 931 | return 0; |
| 932 | } |
| 933 | |
| 934 | /** |
| 935 | * Test if the argument filter can be skipped because it's a tautology |
| 936 | * @param arg argument filter |
| 937 | * |
| 938 | * If this argument filter applied to the lower 32 bit can be skipped this |
| 939 | * function returns false. |
| 940 | * |
| 941 | */ |
| 942 | static bool _db_arg_cmp_need_lo(const struct db_api_arg *arg) |
| 943 | { |
| 944 | if (arg->op == SCMP_CMP_MASKED_EQ && D64_LO(arg->mask) == 0) |
| 945 | return false; |
| 946 | |
| 947 | return true; |
| 948 | } |
| 949 | |
| 950 | /** |
| 951 | * Test if the argument filter can be skipped because it's a tautology |
| 952 | * @param arg argument filter |
| 953 | * |
| 954 | * If this argument filter applied to the upper 32 bit can be skipped this |
| 955 | * function returns false. |
| 956 | * |
| 957 | */ |
| 958 | static bool _db_arg_cmp_need_hi(const struct db_api_arg *arg) |
| 959 | { |
| 960 | if (arg->op == SCMP_CMP_MASKED_EQ && D64_HI(arg->mask) == 0) |
| 961 | return false; |
| 962 | |
| 963 | return true; |
| 964 | } |
| 965 | |
| 966 | /** |
| 967 | * Fixup the node based on the op/mask |
| 968 | * @param node the chain node |
| 969 | * |
| 970 | * Ensure the datum is masked as well. |
| 971 | * |
| 972 | */ |
| 973 | static void _db_node_mask_fixup(struct db_arg_chain_tree *node) |
| 974 | { |
| 975 | node->datum &= node->mask; |
| 976 | } |
| 977 | |
| 978 | /** |
| 979 | * Generate a new filter rule for a 64 bit system |
| 980 | * @param arch the architecture definition |
| 981 | * @param action the filter action |
| 982 | * @param syscall the syscall number |
| 983 | * @param chain argument filter chain |
| 984 | * |
| 985 | * This function generates a new syscall filter for a 64 bit system. Returns |
| 986 | * zero on success, negative values on failure. |
| 987 | * |
| 988 | */ |
| 989 | static struct db_sys_list *_db_rule_gen_64(const struct arch_def *arch, |
| 990 | uint32_t action, |
| 991 | unsigned int syscall, |
| 992 | struct db_api_arg *chain) |
| 993 | { |
| 994 | unsigned int iter; |
| 995 | int chain_len_max; |
| 996 | struct db_sys_list *s_new; |
| 997 | struct db_arg_chain_tree *c_iter_hi = NULL, *c_iter_lo = NULL; |
| 998 | struct db_arg_chain_tree *c_prev_hi = NULL, *c_prev_lo = NULL; |
| 999 | bool tf_flag; |
| 1000 | |
| 1001 | s_new = malloc(sizeof(*s_new)); |
| 1002 | if (s_new == NULL) |
| 1003 | return NULL; |
| 1004 | memset(s_new, 0, sizeof(*s_new)); |
| 1005 | s_new->num = syscall; |
| 1006 | s_new->valid = true; |
| 1007 | /* run through the argument chain */ |
| 1008 | chain_len_max = arch_arg_count_max(arch); |
| 1009 | if (chain_len_max < 0) |
| 1010 | goto gen_64_failure; |
| 1011 | for (iter = 0; iter < chain_len_max; iter++) { |
| 1012 | if (chain[iter].valid == 0) |
| 1013 | continue; |
| 1014 | |
| 1015 | /* TODO: handle the case were either hi or lo isn't needed */ |
| 1016 | |
| 1017 | /* skip generating instruction which are no-ops */ |
| 1018 | if (!_db_arg_cmp_need_hi(&chain[iter]) && |
| 1019 | !_db_arg_cmp_need_lo(&chain[iter])) |
| 1020 | continue; |
| 1021 | |
| 1022 | c_iter_hi = malloc(sizeof(*c_iter_hi)); |
| 1023 | if (c_iter_hi == NULL) |
| 1024 | goto gen_64_failure; |
| 1025 | memset(c_iter_hi, 0, sizeof(*c_iter_hi)); |
| 1026 | c_iter_hi->refcnt = 1; |
| 1027 | c_iter_lo = malloc(sizeof(*c_iter_lo)); |
| 1028 | if (c_iter_lo == NULL) { |
| 1029 | free(c_iter_hi); |
| 1030 | goto gen_64_failure; |
| 1031 | } |
| 1032 | memset(c_iter_lo, 0, sizeof(*c_iter_lo)); |
| 1033 | c_iter_lo->refcnt = 1; |
| 1034 | |
| 1035 | /* link this level to the previous level */ |
| 1036 | if (c_prev_lo != NULL) { |
| 1037 | if (!tf_flag) { |
| 1038 | c_prev_lo->nxt_f = c_iter_hi; |
| 1039 | c_prev_hi->nxt_f = c_iter_hi; |
| 1040 | c_iter_hi->refcnt++; |
| 1041 | } else |
| 1042 | c_prev_lo->nxt_t = c_iter_hi; |
| 1043 | } else |
| 1044 | s_new->chains = c_iter_hi; |
| 1045 | s_new->node_cnt += 2; |
| 1046 | |
| 1047 | /* set the arg, op, and datum fields */ |
| 1048 | c_iter_hi->arg = chain[iter].arg; |
| 1049 | c_iter_lo->arg = chain[iter].arg; |
| 1050 | c_iter_hi->arg_offset = arch_arg_offset_hi(arch, |
| 1051 | c_iter_hi->arg); |
| 1052 | c_iter_lo->arg_offset = arch_arg_offset_lo(arch, |
| 1053 | c_iter_lo->arg); |
| 1054 | switch (chain[iter].op) { |
| 1055 | case SCMP_CMP_GT: |
| 1056 | c_iter_hi->op = SCMP_CMP_GE; |
| 1057 | c_iter_lo->op = SCMP_CMP_GT; |
| 1058 | tf_flag = true; |
| 1059 | break; |
| 1060 | case SCMP_CMP_NE: |
| 1061 | c_iter_hi->op = SCMP_CMP_EQ; |
| 1062 | c_iter_lo->op = SCMP_CMP_EQ; |
| 1063 | tf_flag = false; |
| 1064 | break; |
| 1065 | case SCMP_CMP_LT: |
| 1066 | c_iter_hi->op = SCMP_CMP_GE; |
| 1067 | c_iter_lo->op = SCMP_CMP_GE; |
| 1068 | tf_flag = false; |
| 1069 | break; |
| 1070 | case SCMP_CMP_LE: |
| 1071 | c_iter_hi->op = SCMP_CMP_GE; |
| 1072 | c_iter_lo->op = SCMP_CMP_GT; |
| 1073 | tf_flag = false; |
| 1074 | break; |
| 1075 | default: |
| 1076 | c_iter_hi->op = chain[iter].op; |
| 1077 | c_iter_lo->op = chain[iter].op; |
| 1078 | tf_flag = true; |
| 1079 | } |
| 1080 | c_iter_hi->mask = D64_HI(chain[iter].mask); |
| 1081 | c_iter_lo->mask = D64_LO(chain[iter].mask); |
| 1082 | c_iter_hi->datum = D64_HI(chain[iter].datum); |
| 1083 | c_iter_lo->datum = D64_LO(chain[iter].datum); |
| 1084 | |
| 1085 | /* fixup the mask/datum */ |
| 1086 | _db_node_mask_fixup(c_iter_hi); |
| 1087 | _db_node_mask_fixup(c_iter_lo); |
| 1088 | |
| 1089 | /* link the hi and lo chain nodes */ |
| 1090 | c_iter_hi->nxt_t = c_iter_lo; |
| 1091 | |
| 1092 | c_prev_hi = c_iter_hi; |
| 1093 | c_prev_lo = c_iter_lo; |
| 1094 | } |
| 1095 | if (c_iter_lo != NULL) { |
| 1096 | /* set the leaf node */ |
| 1097 | if (!tf_flag) { |
| 1098 | c_iter_lo->act_f_flg = true; |
| 1099 | c_iter_lo->act_f = action; |
| 1100 | c_iter_hi->act_f_flg = true; |
| 1101 | c_iter_hi->act_f = action; |
| 1102 | } else { |
| 1103 | c_iter_lo->act_t_flg = true; |
| 1104 | c_iter_lo->act_t = action; |
| 1105 | } |
| 1106 | } else |
| 1107 | s_new->action = action; |
| 1108 | |
| 1109 | return s_new; |
| 1110 | |
| 1111 | gen_64_failure: |
| 1112 | /* free the new chain and its syscall struct */ |
| 1113 | _db_tree_free(s_new->chains); |
| 1114 | free(s_new); |
| 1115 | return NULL; |
| 1116 | } |
| 1117 | |
| 1118 | /** |
| 1119 | * Generate a new filter rule for a 32 bit system |
| 1120 | * @param arch the architecture definition |
| 1121 | * @param action the filter action |
| 1122 | * @param syscall the syscall number |
| 1123 | * @param chain argument filter chain |
| 1124 | * |
| 1125 | * This function generates a new syscall filter for a 32 bit system. Returns |
| 1126 | * zero on success, negative values on failure. |
| 1127 | * |
| 1128 | */ |
| 1129 | static struct db_sys_list *_db_rule_gen_32(const struct arch_def *arch, |
| 1130 | uint32_t action, |
| 1131 | unsigned int syscall, |
| 1132 | struct db_api_arg *chain) |
| 1133 | { |
| 1134 | unsigned int iter; |
| 1135 | int chain_len_max; |
| 1136 | struct db_sys_list *s_new; |
| 1137 | struct db_arg_chain_tree *c_iter = NULL, *c_prev = NULL; |
| 1138 | bool tf_flag; |
| 1139 | |
| 1140 | s_new = malloc(sizeof(*s_new)); |
| 1141 | if (s_new == NULL) |
| 1142 | return NULL; |
| 1143 | memset(s_new, 0, sizeof(*s_new)); |
| 1144 | s_new->num = syscall; |
| 1145 | s_new->valid = true; |
| 1146 | /* run through the argument chain */ |
| 1147 | chain_len_max = arch_arg_count_max(arch); |
| 1148 | if (chain_len_max < 0) |
| 1149 | goto gen_32_failure; |
| 1150 | for (iter = 0; iter < chain_len_max; iter++) { |
| 1151 | if (chain[iter].valid == 0) |
| 1152 | continue; |
| 1153 | |
| 1154 | /* skip generating instructions which are no-ops */ |
| 1155 | if (!_db_arg_cmp_need_lo(&chain[iter])) |
| 1156 | continue; |
| 1157 | |
| 1158 | c_iter = malloc(sizeof(*c_iter)); |
| 1159 | if (c_iter == NULL) |
| 1160 | goto gen_32_failure; |
| 1161 | memset(c_iter, 0, sizeof(*c_iter)); |
| 1162 | c_iter->refcnt = 1; |
| 1163 | c_iter->arg = chain[iter].arg; |
| 1164 | c_iter->arg_offset = arch_arg_offset(arch, c_iter->arg); |
| 1165 | c_iter->op = chain[iter].op; |
| 1166 | /* implicitly strips off the upper 32 bit */ |
| 1167 | c_iter->mask = chain[iter].mask; |
| 1168 | c_iter->datum = chain[iter].datum; |
| 1169 | |
| 1170 | /* link in the new node and update the chain */ |
| 1171 | if (c_prev != NULL) { |
| 1172 | if (tf_flag) |
| 1173 | c_prev->nxt_t = c_iter; |
| 1174 | else |
| 1175 | c_prev->nxt_f = c_iter; |
| 1176 | } else |
| 1177 | s_new->chains = c_iter; |
| 1178 | s_new->node_cnt++; |
| 1179 | |
| 1180 | /* rewrite the op to reduce the op/datum combos */ |
| 1181 | switch (c_iter->op) { |
| 1182 | case SCMP_CMP_NE: |
| 1183 | c_iter->op = SCMP_CMP_EQ; |
| 1184 | tf_flag = false; |
| 1185 | break; |
| 1186 | case SCMP_CMP_LT: |
| 1187 | c_iter->op = SCMP_CMP_GE; |
| 1188 | tf_flag = false; |
| 1189 | break; |
| 1190 | case SCMP_CMP_LE: |
| 1191 | c_iter->op = SCMP_CMP_GT; |
| 1192 | tf_flag = false; |
| 1193 | break; |
| 1194 | default: |
| 1195 | tf_flag = true; |
| 1196 | } |
| 1197 | |
| 1198 | /* fixup the mask/datum */ |
| 1199 | _db_node_mask_fixup(c_iter); |
| 1200 | |
| 1201 | c_prev = c_iter; |
| 1202 | } |
| 1203 | if (c_iter != NULL) { |
| 1204 | /* set the leaf node */ |
| 1205 | if (tf_flag) { |
| 1206 | c_iter->act_t_flg = true; |
| 1207 | c_iter->act_t = action; |
| 1208 | } else { |
| 1209 | c_iter->act_f_flg = true; |
| 1210 | c_iter->act_f = action; |
| 1211 | } |
| 1212 | } else |
| 1213 | s_new->action = action; |
| 1214 | |
| 1215 | return s_new; |
| 1216 | |
| 1217 | gen_32_failure: |
| 1218 | /* free the new chain and its syscall struct */ |
| 1219 | _db_tree_free(s_new->chains); |
| 1220 | free(s_new); |
| 1221 | return NULL; |
| 1222 | } |
| 1223 | |
| 1224 | /** |
| 1225 | * Add a new rule to the seccomp filter DB |
| 1226 | * @param db the seccomp filter db |
| 1227 | * @param rule the filter rule |
| 1228 | * |
| 1229 | * This function adds a new syscall filter to the seccomp filter DB, adding to |
| 1230 | * the existing filters for the syscall, unless no argument specific filters |
| 1231 | * are present (filtering only on the syscall). When adding new chains, the |
| 1232 | * shortest chain, or most inclusive filter match, will be entered into the |
| 1233 | * filter DB. Returns zero on success, negative values on failure. |
| 1234 | * |
| 1235 | */ |
| 1236 | int db_rule_add(struct db_filter *db, const struct db_api_rule_list *rule) |
| 1237 | { |
| 1238 | int rc = -ENOMEM; |
| 1239 | int syscall = rule->syscall; |
| 1240 | uint32_t action = rule->action; |
| 1241 | struct db_api_arg *chain = rule->args; |
| 1242 | struct db_sys_list *s_new, *s_iter, *s_prev = NULL; |
| 1243 | struct db_arg_chain_tree *c_iter = NULL, *c_prev = NULL; |
| 1244 | struct db_arg_chain_tree *ec_iter; |
| 1245 | struct db_prune_state state; |
| 1246 | bool rm_flag = false; |
| 1247 | unsigned int new_chain_cnt = 0; |
| 1248 | unsigned int n_cnt; |
| 1249 | |
| 1250 | assert(db != NULL); |
| 1251 | |
| 1252 | /* do all our possible memory allocation up front so we don't have to |
| 1253 | * worry about failure once we get to the point where we start updating |
| 1254 | * the filter db */ |
| 1255 | if (db->arch->size == ARCH_SIZE_64) |
| 1256 | s_new = _db_rule_gen_64(db->arch, action, syscall, chain); |
| 1257 | else if (db->arch->size == ARCH_SIZE_32) |
| 1258 | s_new = _db_rule_gen_32(db->arch, action, syscall, chain); |
| 1259 | else |
| 1260 | return -EFAULT; |
| 1261 | if (s_new == NULL) |
| 1262 | return -ENOMEM; |
| 1263 | new_chain_cnt = s_new->node_cnt; |
| 1264 | |
| 1265 | /* no more failures allowed after this point that would result in the |
| 1266 | * stored filter being in an inconsistent state */ |
| 1267 | |
| 1268 | /* find a matching syscall/chain or insert a new one */ |
| 1269 | s_iter = db->syscalls; |
| 1270 | while (s_iter != NULL && s_iter->num < syscall) { |
| 1271 | s_prev = s_iter; |
| 1272 | s_iter = s_iter->next; |
| 1273 | } |
| 1274 | add_reset: |
| 1275 | s_new->node_cnt = new_chain_cnt; |
| 1276 | s_new->priority = _DB_PRI_MASK_CHAIN - s_new->node_cnt; |
| 1277 | c_prev = NULL; |
| 1278 | c_iter = s_new->chains; |
| 1279 | if (s_iter != NULL) |
| 1280 | ec_iter = s_iter->chains; |
| 1281 | else |
| 1282 | ec_iter = NULL; |
| 1283 | if (s_iter == NULL || s_iter->num != syscall) { |
| 1284 | /* new syscall, add before s_iter */ |
| 1285 | if (s_prev != NULL) { |
| 1286 | s_new->next = s_prev->next; |
| 1287 | s_prev->next = s_new; |
| 1288 | } else { |
| 1289 | s_new->next = db->syscalls; |
| 1290 | db->syscalls = s_new; |
| 1291 | } |
| 1292 | return 0; |
| 1293 | } else if (s_iter->chains == NULL) { |
| 1294 | if (rm_flag || !s_iter->valid) { |
| 1295 | /* we are here because our previous pass cleared the |
| 1296 | * entire syscall chain when searching for a subtree |
| 1297 | * match or the existing syscall entry is a phantom, |
| 1298 | * so either way add the new chain */ |
| 1299 | s_iter->chains = s_new->chains; |
| 1300 | s_iter->action = s_new->action; |
| 1301 | s_iter->node_cnt = s_new->node_cnt; |
| 1302 | if (s_iter->valid) |
| 1303 | s_iter->priority = s_new->priority; |
| 1304 | s_iter->valid = true; |
| 1305 | free(s_new); |
| 1306 | rc = 0; |
| 1307 | goto add_priority_update; |
| 1308 | } else |
| 1309 | /* syscall exists without any chains - existing filter |
| 1310 | * is at least as large as the new entry so cleanup and |
| 1311 | * exit */ |
| 1312 | goto add_free_ok; |
| 1313 | } else if (s_iter->chains != NULL && s_new->chains == NULL) { |
| 1314 | /* syscall exists with chains but the new filter has no chains |
| 1315 | * so we need to clear the existing chains and exit */ |
| 1316 | _db_tree_free(s_iter->chains); |
| 1317 | s_iter->chains = NULL; |
| 1318 | s_iter->node_cnt = 0; |
| 1319 | s_iter->action = action; |
| 1320 | goto add_free_ok; |
| 1321 | } |
| 1322 | |
| 1323 | /* check for sub-tree matches */ |
| 1324 | memset(&state, 0, sizeof(state)); |
| 1325 | rc = _db_tree_sub_prune(&(s_iter->chains), ec_iter, c_iter, &state); |
| 1326 | if (rc > 0) { |
| 1327 | rm_flag = true; |
| 1328 | s_iter->node_cnt -= rc; |
| 1329 | goto add_reset; |
| 1330 | } else if (rc < 0) |
| 1331 | goto add_free_ok; |
| 1332 | |
| 1333 | /* syscall exists and has at least one existing chain - start at the |
| 1334 | * top and walk the two chains */ |
| 1335 | do { |
| 1336 | /* insert the new rule into the existing tree */ |
| 1337 | if (db_chain_eq(c_iter, ec_iter)) { |
| 1338 | /* found a matching node on this chain level */ |
| 1339 | if (db_chain_action(c_iter) && |
| 1340 | db_chain_action(ec_iter)) { |
| 1341 | /* both are "action" nodes */ |
| 1342 | if (c_iter->act_t_flg && ec_iter->act_t_flg) { |
| 1343 | if (ec_iter->act_t != action) |
| 1344 | goto add_free_exist; |
| 1345 | } else if (c_iter->act_t_flg) { |
| 1346 | ec_iter->act_t_flg = true; |
| 1347 | ec_iter->act_t = action; |
| 1348 | } |
| 1349 | if (c_iter->act_f_flg && ec_iter->act_f_flg) { |
| 1350 | if (ec_iter->act_f != action) |
| 1351 | goto add_free_exist; |
| 1352 | } else if (c_iter->act_f_flg) { |
| 1353 | ec_iter->act_f_flg = true; |
| 1354 | ec_iter->act_f = action; |
| 1355 | } |
| 1356 | if (ec_iter->act_t_flg == ec_iter->act_f_flg && |
| 1357 | ec_iter->act_t == ec_iter->act_f) { |
| 1358 | n_cnt = _db_tree_remove( |
| 1359 | &(s_iter->chains), |
| 1360 | ec_iter); |
| 1361 | s_iter->node_cnt -= n_cnt; |
| 1362 | goto add_free_ok; |
| 1363 | } |
| 1364 | } else if (db_chain_action(c_iter)) { |
| 1365 | /* new is shorter */ |
| 1366 | if (c_iter->act_t_flg) { |
| 1367 | rc = _db_tree_act_check(ec_iter->nxt_t, |
| 1368 | action); |
| 1369 | if (rc < 0) |
| 1370 | goto add_free; |
| 1371 | n_cnt = _db_tree_free(ec_iter->nxt_t); |
| 1372 | ec_iter->nxt_t = NULL; |
| 1373 | ec_iter->act_t_flg = true; |
| 1374 | ec_iter->act_t = action; |
| 1375 | } else { |
| 1376 | rc = _db_tree_act_check(ec_iter->nxt_f, |
| 1377 | action); |
| 1378 | if (rc < 0) |
| 1379 | goto add_free; |
| 1380 | n_cnt = _db_tree_free(ec_iter->nxt_f); |
| 1381 | ec_iter->nxt_f = NULL; |
| 1382 | ec_iter->act_f_flg = true; |
| 1383 | ec_iter->act_f = action; |
| 1384 | } |
| 1385 | s_iter->node_cnt -= n_cnt; |
| 1386 | } |
| 1387 | if (c_iter->nxt_t != NULL) { |
| 1388 | if (ec_iter->nxt_t != NULL) { |
| 1389 | /* jump to the next level */ |
| 1390 | c_prev = c_iter; |
| 1391 | c_iter = c_iter->nxt_t; |
| 1392 | ec_iter = ec_iter->nxt_t; |
| 1393 | s_new->node_cnt--; |
| 1394 | } else if (ec_iter->act_t_flg) { |
| 1395 | /* existing is shorter */ |
| 1396 | if (ec_iter->act_t == action) |
| 1397 | goto add_free_ok; |
| 1398 | goto add_free_exist; |
| 1399 | } else { |
| 1400 | /* add a new branch */ |
| 1401 | c_prev = c_iter; |
| 1402 | ec_iter->nxt_t = c_iter->nxt_t; |
| 1403 | s_iter->node_cnt += |
| 1404 | (s_new->node_cnt - 1); |
| 1405 | goto add_free_match; |
| 1406 | } |
| 1407 | } else if (c_iter->nxt_f != NULL) { |
| 1408 | if (ec_iter->nxt_f != NULL) { |
| 1409 | /* jump to the next level */ |
| 1410 | c_prev = c_iter; |
| 1411 | c_iter = c_iter->nxt_f; |
| 1412 | ec_iter = ec_iter->nxt_f; |
| 1413 | s_new->node_cnt--; |
| 1414 | } else if (ec_iter->act_f_flg) { |
| 1415 | /* existing is shorter */ |
| 1416 | if (ec_iter->act_f == action) |
| 1417 | goto add_free_ok; |
| 1418 | goto add_free_exist; |
| 1419 | } else { |
| 1420 | /* add a new branch */ |
| 1421 | c_prev = c_iter; |
| 1422 | ec_iter->nxt_f = c_iter->nxt_f; |
| 1423 | s_iter->node_cnt += |
| 1424 | (s_new->node_cnt - 1); |
| 1425 | goto add_free_match; |
| 1426 | } |
| 1427 | } else |
| 1428 | goto add_free_ok; |
| 1429 | } else { |
| 1430 | /* need to check other nodes on this level */ |
| 1431 | if (db_chain_lt(c_iter, ec_iter)) { |
| 1432 | if (ec_iter->lvl_prv == NULL) { |
| 1433 | /* add to the start of the level */ |
| 1434 | ec_iter->lvl_prv = c_iter; |
| 1435 | c_iter->lvl_nxt = ec_iter; |
| 1436 | if (ec_iter == s_iter->chains) |
| 1437 | s_iter->chains = c_iter; |
| 1438 | s_iter->node_cnt += s_new->node_cnt; |
| 1439 | goto add_free_match; |
| 1440 | } else |
| 1441 | ec_iter = ec_iter->lvl_prv; |
| 1442 | } else { |
| 1443 | if (ec_iter->lvl_nxt == NULL) { |
| 1444 | /* add to the end of the level */ |
| 1445 | ec_iter->lvl_nxt = c_iter; |
| 1446 | c_iter->lvl_prv = ec_iter; |
| 1447 | s_iter->node_cnt += s_new->node_cnt; |
| 1448 | goto add_free_match; |
| 1449 | } else if (db_chain_lt(c_iter, |
| 1450 | ec_iter->lvl_nxt)) { |
| 1451 | /* add new chain in between */ |
| 1452 | c_iter->lvl_nxt = ec_iter->lvl_nxt; |
| 1453 | ec_iter->lvl_nxt->lvl_prv = c_iter; |
| 1454 | ec_iter->lvl_nxt = c_iter; |
| 1455 | c_iter->lvl_prv = ec_iter; |
| 1456 | s_iter->node_cnt += s_new->node_cnt; |
| 1457 | goto add_free_match; |
| 1458 | } else |
| 1459 | ec_iter = ec_iter->lvl_nxt; |
| 1460 | } |
| 1461 | } |
| 1462 | } while ((c_iter != NULL) && (ec_iter != NULL)); |
| 1463 | |
| 1464 | /* we should never be here! */ |
| 1465 | return -EFAULT; |
| 1466 | |
| 1467 | add_free_exist: |
| 1468 | rc = -EEXIST; |
| 1469 | goto add_free; |
| 1470 | add_free_ok: |
| 1471 | rc = 0; |
| 1472 | add_free: |
| 1473 | /* free the new chain and its syscall struct */ |
| 1474 | _db_tree_free(s_new->chains); |
| 1475 | free(s_new); |
| 1476 | goto add_priority_update; |
| 1477 | add_free_match: |
| 1478 | /* free the matching portion of new chain */ |
| 1479 | if (c_prev != NULL) { |
| 1480 | c_prev->nxt_t = NULL; |
| 1481 | c_prev->nxt_f = NULL; |
| 1482 | _db_tree_free(s_new->chains); |
| 1483 | } |
| 1484 | free(s_new); |
| 1485 | rc = 0; |
| 1486 | add_priority_update: |
| 1487 | /* update the priority */ |
| 1488 | if (s_iter != NULL) { |
| 1489 | s_iter->priority &= (~_DB_PRI_MASK_CHAIN); |
| 1490 | s_iter->priority |= (_DB_PRI_MASK_CHAIN - s_iter->node_cnt); |
| 1491 | } |
| 1492 | return rc; |
| 1493 | } |
| 1494 | |
| 1495 | /** |
| 1496 | * Set the priority of a given syscall |
| 1497 | * @param col the filter collection |
| 1498 | * @param syscall the syscall number |
| 1499 | * @param priority priority value, higher value == higher priority |
| 1500 | * |
| 1501 | * This function sets the priority of the given syscall; this value is used |
| 1502 | * when generating the seccomp filter code such that higher priority syscalls |
| 1503 | * will incur less filter code overhead than the lower priority syscalls in the |
| 1504 | * filter. Returns zero on success, negative values on failure. |
| 1505 | * |
| 1506 | */ |
| 1507 | int db_col_syscall_priority(struct db_filter_col *col, |
| 1508 | int syscall, uint8_t priority) |
| 1509 | { |
| 1510 | int rc = 0, rc_tmp; |
| 1511 | unsigned int iter; |
| 1512 | int sc_tmp; |
| 1513 | struct db_filter *filter; |
| 1514 | |
| 1515 | for (iter = 0; iter < col->filter_cnt; iter++) { |
| 1516 | filter = col->filters[iter]; |
| 1517 | sc_tmp = syscall; |
| 1518 | |
| 1519 | rc_tmp = arch_syscall_translate(filter->arch, &sc_tmp); |
| 1520 | if (rc_tmp < 0) |
| 1521 | goto priority_failure; |
| 1522 | |
| 1523 | /* if this is a pseudo syscall (syscall < 0) then we need to |
| 1524 | * rewrite the syscall for some arch specific reason */ |
| 1525 | if (sc_tmp < 0) { |
| 1526 | /* we set this as a strict op - we don't really care |
| 1527 | * since priorities are a "best effort" thing - as we |
| 1528 | * want to catch the -EDOM error and bail on this |
| 1529 | * architecture */ |
| 1530 | rc_tmp = arch_syscall_rewrite(filter->arch, &sc_tmp); |
| 1531 | if (rc_tmp == -EDOM) |
| 1532 | continue; |
| 1533 | if (rc_tmp < 0) |
| 1534 | goto priority_failure; |
| 1535 | } |
| 1536 | |
| 1537 | rc_tmp = _db_syscall_priority(filter, sc_tmp, priority); |
| 1538 | |
| 1539 | priority_failure: |
| 1540 | if (rc == 0 && rc_tmp < 0) |
| 1541 | rc = rc_tmp; |
| 1542 | } |
| 1543 | |
| 1544 | return rc; |
| 1545 | } |
| 1546 | |
| 1547 | /** |
| 1548 | * Add a new rule to the current filter |
| 1549 | * @param col the filter collection |
| 1550 | * @param strict the strict flag |
| 1551 | * @param action the filter action |
| 1552 | * @param syscall the syscall number |
| 1553 | * @param arg_cnt the number of argument filters in the argument filter chain |
| 1554 | * @param arg_array the argument filter chain, (uint, enum scmp_compare, ulong) |
| 1555 | * |
| 1556 | * This function adds a new argument/comparison/value to the seccomp filter for |
| 1557 | * a syscall; multiple arguments can be specified and they will be chained |
| 1558 | * together (essentially AND'd together) in the filter. When the strict flag |
| 1559 | * is true the function will fail if the exact rule can not be added to the |
| 1560 | * filter, if the strict flag is false the function will not fail if the |
| 1561 | * function needs to adjust the rule due to architecture specifics. Returns |
| 1562 | * zero on success, negative values on failure. |
| 1563 | * |
| 1564 | */ |
| 1565 | int db_col_rule_add(struct db_filter_col *col, |
| 1566 | bool strict, uint32_t action, int syscall, |
| 1567 | unsigned int arg_cnt, const struct scmp_arg_cmp *arg_array) |
| 1568 | { |
| 1569 | int rc = 0, rc_tmp; |
| 1570 | unsigned int iter; |
| 1571 | unsigned int chain_len; |
| 1572 | unsigned int arg_num; |
| 1573 | size_t chain_size; |
| 1574 | struct db_api_arg *chain = NULL; |
| 1575 | struct scmp_arg_cmp arg_data; |
| 1576 | |
| 1577 | /* collect the arguments for the filter rule */ |
| 1578 | chain_len = ARG_COUNT_MAX; |
| 1579 | chain_size = sizeof(*chain) * chain_len; |
| 1580 | chain = malloc(chain_size); |
| 1581 | if (chain == NULL) |
| 1582 | return -ENOMEM; |
| 1583 | memset(chain, 0, chain_size); |
| 1584 | for (iter = 0; iter < arg_cnt; iter++) { |
| 1585 | arg_data = arg_array[iter]; |
| 1586 | arg_num = arg_data.arg; |
| 1587 | if (arg_num < chain_len && chain[arg_num].valid == 0) { |
| 1588 | chain[arg_num].valid = 1; |
| 1589 | chain[arg_num].arg = arg_num; |
| 1590 | chain[arg_num].op = arg_data.op; |
| 1591 | /* XXX - we should check datum/mask size against the |
| 1592 | * arch definition, e.g. 64 bit datum on x86 */ |
| 1593 | switch (chain[arg_num].op) { |
| 1594 | case SCMP_CMP_NE: |
| 1595 | case SCMP_CMP_LT: |
| 1596 | case SCMP_CMP_LE: |
| 1597 | case SCMP_CMP_EQ: |
| 1598 | case SCMP_CMP_GE: |
| 1599 | case SCMP_CMP_GT: |
| 1600 | chain[arg_num].mask = DATUM_MAX; |
| 1601 | chain[arg_num].datum = arg_data.datum_a; |
| 1602 | break; |
| 1603 | case SCMP_CMP_MASKED_EQ: |
| 1604 | chain[arg_num].mask = arg_data.datum_a; |
| 1605 | chain[arg_num].datum = arg_data.datum_b; |
| 1606 | break; |
| 1607 | default: |
| 1608 | rc = -EINVAL; |
| 1609 | goto add_return; |
| 1610 | } |
| 1611 | } else { |
| 1612 | rc = -EINVAL; |
| 1613 | goto add_return; |
| 1614 | } |
| 1615 | } |
| 1616 | |
| 1617 | for (iter = 0; iter < col->filter_cnt; iter++) { |
| 1618 | rc_tmp = arch_filter_rule_add(col, col->filters[iter], strict, |
| 1619 | action, syscall, |
| 1620 | chain_len, chain); |
| 1621 | if (rc == 0 && rc_tmp < 0) |
| 1622 | rc = rc_tmp; |
| 1623 | } |
| 1624 | |
| 1625 | add_return: |
| 1626 | if (chain != NULL) |
| 1627 | free(chain); |
| 1628 | return rc; |
| 1629 | } |
| 1630 | |
| 1631 | /** |
| 1632 | * Start a new seccomp filter transaction |
| 1633 | * @param col the filter collection |
| 1634 | * |
| 1635 | * This function starts a new seccomp filter transaction for the given filter |
| 1636 | * collection. Returns zero on success, negative values on failure. |
| 1637 | * |
| 1638 | */ |
| 1639 | int db_col_transaction_start(struct db_filter_col *col) |
| 1640 | { |
| 1641 | unsigned int iter; |
| 1642 | size_t args_size; |
| 1643 | struct db_filter_snap *snap; |
| 1644 | struct db_filter *filter_o, *filter_s; |
| 1645 | struct db_api_rule_list *rule_o, *rule_s; |
| 1646 | |
| 1647 | /* allocate the snapshot */ |
| 1648 | snap = malloc(sizeof(*snap)); |
| 1649 | if (snap == NULL) |
| 1650 | return -ENOMEM; |
| 1651 | snap->filters = malloc(sizeof(struct db_filter *) * col->filter_cnt); |
| 1652 | if (snap->filters == NULL) { |
| 1653 | free(snap); |
| 1654 | return -ENOMEM; |
| 1655 | } |
| 1656 | snap->filter_cnt = col->filter_cnt; |
| 1657 | for (iter = 0; iter < snap->filter_cnt; iter++) |
| 1658 | snap->filters[iter] = NULL; |
| 1659 | snap->next = NULL; |
| 1660 | |
| 1661 | /* create a snapshot of the current filter state */ |
| 1662 | for (iter = 0; iter < col->filter_cnt; iter++) { |
| 1663 | /* allocate a new filter */ |
| 1664 | filter_o = col->filters[iter]; |
| 1665 | filter_s = _db_init(filter_o->arch); |
| 1666 | if (filter_s == NULL) |
| 1667 | goto trans_start_failure; |
| 1668 | snap->filters[iter] = filter_s; |
| 1669 | |
| 1670 | /* create a filter snapshot from existing rules */ |
| 1671 | rule_o = filter_o->rules; |
| 1672 | if (rule_o == NULL) |
| 1673 | continue; |
| 1674 | do { |
| 1675 | /* copy the rule */ |
| 1676 | rule_s = malloc(sizeof(*rule_s)); |
| 1677 | if (rule_s == NULL) |
| 1678 | goto trans_start_failure; |
| 1679 | args_size = sizeof(*rule_s->args) * rule_o->args_cnt; |
| 1680 | rule_s->args = malloc(args_size); |
| 1681 | if (rule_s->args == NULL) { |
| 1682 | free(rule_s); |
| 1683 | goto trans_start_failure; |
| 1684 | } |
| 1685 | rule_s->action = rule_o->action; |
| 1686 | rule_s->syscall = rule_o->syscall; |
| 1687 | rule_s->args_cnt = rule_o->args_cnt; |
| 1688 | memcpy(rule_s->args, rule_o->args, args_size); |
| 1689 | if (filter_s->rules != NULL) { |
| 1690 | rule_s->prev = filter_s->rules->prev; |
| 1691 | rule_s->next = filter_s->rules; |
| 1692 | filter_s->rules->prev->next = rule_s; |
| 1693 | filter_s->rules->prev = rule_s; |
| 1694 | } else { |
| 1695 | rule_s->prev = rule_s; |
| 1696 | rule_s->next = rule_s; |
| 1697 | filter_s->rules = rule_s; |
| 1698 | } |
| 1699 | |
| 1700 | /* insert the rule into the filter */ |
| 1701 | if (db_rule_add(filter_s, rule_o) != 0) |
| 1702 | goto trans_start_failure; |
| 1703 | |
| 1704 | /* next rule */ |
| 1705 | rule_o = rule_o->next; |
| 1706 | } while (rule_o != filter_o->rules); |
| 1707 | } |
| 1708 | |
| 1709 | /* add the snapshot to the list */ |
| 1710 | snap->next = col->snapshots; |
| 1711 | col->snapshots = snap; |
| 1712 | |
| 1713 | return 0; |
| 1714 | |
| 1715 | trans_start_failure: |
| 1716 | _db_snap_release(snap); |
| 1717 | return -ENOMEM; |
| 1718 | } |
| 1719 | |
| 1720 | /** |
| 1721 | * Abort the top most seccomp filter transaction |
| 1722 | * @param col the filter collection |
| 1723 | * |
| 1724 | * This function aborts the most recent seccomp filter transaction. |
| 1725 | * |
| 1726 | */ |
| 1727 | void db_col_transaction_abort(struct db_filter_col *col) |
| 1728 | { |
| 1729 | int iter; |
| 1730 | unsigned int filter_cnt; |
| 1731 | struct db_filter **filters; |
| 1732 | struct db_filter_snap *snap; |
| 1733 | |
| 1734 | if (col->snapshots == NULL) |
| 1735 | return; |
| 1736 | |
| 1737 | /* replace the current filter with the last snapshot */ |
| 1738 | snap = col->snapshots; |
| 1739 | col->snapshots = snap->next; |
| 1740 | filter_cnt = col->filter_cnt; |
| 1741 | filters = col->filters; |
| 1742 | col->filter_cnt = snap->filter_cnt; |
| 1743 | col->filters = snap->filters; |
| 1744 | free(snap); |
| 1745 | |
| 1746 | /* free the filter we swapped out */ |
| 1747 | for (iter = 0; iter < filter_cnt; iter++) |
| 1748 | _db_release(filters[iter]); |
| 1749 | free(filters); |
| 1750 | } |
| 1751 | |
| 1752 | /** |
| 1753 | * Commit the top most seccomp filter transaction |
| 1754 | * @param col the filter collection |
| 1755 | * |
| 1756 | * This function commits the most recent seccomp filter transaction. |
| 1757 | * |
| 1758 | */ |
| 1759 | void db_col_transaction_commit(struct db_filter_col *col) |
| 1760 | { |
| 1761 | struct db_filter_snap *snap; |
| 1762 | |
| 1763 | snap = col->snapshots; |
| 1764 | col->snapshots = snap->next; |
| 1765 | _db_snap_release(snap); |
| 1766 | } |