1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* auditfilter.c -- filtering of audit events 3 * 4 * Copyright 2003-2004 Red Hat, Inc. 5 * Copyright 2005 Hewlett-Packard Development Company, L.P. 6 * Copyright 2005 IBM Corporation 7 */ 8 9 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 10 11 #include <linux/kernel.h> 12 #include <linux/audit.h> 13 #include <linux/kthread.h> 14 #include <linux/mutex.h> 15 #include <linux/fs.h> 16 #include <linux/namei.h> 17 #include <linux/netlink.h> 18 #include <linux/sched.h> 19 #include <linux/slab.h> 20 #include <linux/security.h> 21 #include <net/net_namespace.h> 22 #include <net/sock.h> 23 #include "audit.h" 24 25 /* 26 * Locking model: 27 * 28 * audit_filter_mutex: 29 * Synchronizes writes and blocking reads of audit's filterlist 30 * data. Rcu is used to traverse the filterlist and access 31 * contents of structs audit_entry, audit_watch and opaque 32 * LSM rules during filtering. If modified, these structures 33 * must be copied and replace their counterparts in the filterlist. 34 * An audit_parent struct is not accessed during filtering, so may 35 * be written directly provided audit_filter_mutex is held. 36 */ 37 38 /* Audit filter lists, defined in <linux/audit.h> */ 39 struct list_head audit_filter_list[AUDIT_NR_FILTERS] = { 40 LIST_HEAD_INIT(audit_filter_list[0]), 41 LIST_HEAD_INIT(audit_filter_list[1]), 42 LIST_HEAD_INIT(audit_filter_list[2]), 43 LIST_HEAD_INIT(audit_filter_list[3]), 44 LIST_HEAD_INIT(audit_filter_list[4]), 45 LIST_HEAD_INIT(audit_filter_list[5]), 46 LIST_HEAD_INIT(audit_filter_list[6]), 47 #if AUDIT_NR_FILTERS != 7 48 #error Fix audit_filter_list initialiser 49 #endif 50 }; 51 static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = { 52 LIST_HEAD_INIT(audit_rules_list[0]), 53 LIST_HEAD_INIT(audit_rules_list[1]), 54 LIST_HEAD_INIT(audit_rules_list[2]), 55 LIST_HEAD_INIT(audit_rules_list[3]), 56 LIST_HEAD_INIT(audit_rules_list[4]), 57 LIST_HEAD_INIT(audit_rules_list[5]), 58 LIST_HEAD_INIT(audit_rules_list[6]), 59 }; 60 61 DEFINE_MUTEX(audit_filter_mutex); 62 63 static void audit_free_lsm_field(struct audit_field *f) 64 { 65 switch (f->type) { 66 case AUDIT_SUBJ_USER: 67 case AUDIT_SUBJ_ROLE: 68 case AUDIT_SUBJ_TYPE: 69 case AUDIT_SUBJ_SEN: 70 case AUDIT_SUBJ_CLR: 71 case AUDIT_OBJ_USER: 72 case AUDIT_OBJ_ROLE: 73 case AUDIT_OBJ_TYPE: 74 case AUDIT_OBJ_LEV_LOW: 75 case AUDIT_OBJ_LEV_HIGH: 76 kfree(f->lsm_str); 77 security_audit_rule_free(f->lsm_rule); 78 } 79 } 80 81 static inline void audit_free_rule(struct audit_entry *e) 82 { 83 int i; 84 struct audit_krule *erule = &e->rule; 85 86 /* some rules don't have associated watches */ 87 if (erule->watch) 88 audit_put_watch(erule->watch); 89 if (erule->fields) 90 for (i = 0; i < erule->field_count; i++) 91 audit_free_lsm_field(&erule->fields[i]); 92 kfree(erule->fields); 93 kfree(erule->filterkey); 94 kfree(e); 95 } 96 97 void audit_free_rule_rcu(struct rcu_head *head) 98 { 99 struct audit_entry *e = container_of(head, struct audit_entry, rcu); 100 audit_free_rule(e); 101 } 102 103 /* Initialize an audit filterlist entry. */ 104 static inline struct audit_entry *audit_init_entry(u32 field_count) 105 { 106 struct audit_entry *entry; 107 struct audit_field *fields; 108 109 entry = kzalloc(sizeof(*entry), GFP_KERNEL); 110 if (unlikely(!entry)) 111 return NULL; 112 113 fields = kcalloc(field_count, sizeof(*fields), GFP_KERNEL); 114 if (unlikely(!fields)) { 115 kfree(entry); 116 return NULL; 117 } 118 entry->rule.fields = fields; 119 120 return entry; 121 } 122 123 /* Unpack a filter field's string representation from user-space 124 * buffer. */ 125 char *audit_unpack_string(void **bufp, size_t *remain, size_t len) 126 { 127 char *str; 128 129 if (!*bufp || (len == 0) || (len > *remain)) 130 return ERR_PTR(-EINVAL); 131 132 /* Of the currently implemented string fields, PATH_MAX 133 * defines the longest valid length. 134 */ 135 if (len > PATH_MAX) 136 return ERR_PTR(-ENAMETOOLONG); 137 138 str = kmalloc(len + 1, GFP_KERNEL); 139 if (unlikely(!str)) 140 return ERR_PTR(-ENOMEM); 141 142 memcpy(str, *bufp, len); 143 str[len] = 0; 144 *bufp += len; 145 *remain -= len; 146 147 return str; 148 } 149 150 /* Translate an inode field to kernel representation. */ 151 static inline int audit_to_inode(struct audit_krule *krule, 152 struct audit_field *f) 153 { 154 if (krule->listnr != AUDIT_FILTER_EXIT || 155 krule->inode_f || krule->watch || krule->tree || 156 (f->op != Audit_equal && f->op != Audit_not_equal)) 157 return -EINVAL; 158 159 krule->inode_f = f; 160 return 0; 161 } 162 163 static __u32 *classes[AUDIT_SYSCALL_CLASSES]; 164 165 int __init audit_register_class(int class, unsigned *list) 166 { 167 __u32 *p = kcalloc(AUDIT_BITMASK_SIZE, sizeof(__u32), GFP_KERNEL); 168 if (!p) 169 return -ENOMEM; 170 while (*list != ~0U) { 171 unsigned n = *list++; 172 if (n >= AUDIT_BITMASK_SIZE * 32 - AUDIT_SYSCALL_CLASSES) { 173 kfree(p); 174 return -EINVAL; 175 } 176 p[AUDIT_WORD(n)] |= AUDIT_BIT(n); 177 } 178 if (class >= AUDIT_SYSCALL_CLASSES || classes[class]) { 179 kfree(p); 180 return -EINVAL; 181 } 182 classes[class] = p; 183 return 0; 184 } 185 186 int audit_match_class(int class, unsigned syscall) 187 { 188 if (unlikely(syscall >= AUDIT_BITMASK_SIZE * 32)) 189 return 0; 190 if (unlikely(class >= AUDIT_SYSCALL_CLASSES || !classes[class])) 191 return 0; 192 return classes[class][AUDIT_WORD(syscall)] & AUDIT_BIT(syscall); 193 } 194 195 #ifdef CONFIG_AUDITSYSCALL 196 static inline int audit_match_class_bits(int class, u32 *mask) 197 { 198 int i; 199 200 if (classes[class]) { 201 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) 202 if (mask[i] & classes[class][i]) 203 return 0; 204 } 205 return 1; 206 } 207 208 static int audit_match_signal(struct audit_entry *entry) 209 { 210 struct audit_field *arch = entry->rule.arch_f; 211 212 if (!arch) { 213 /* When arch is unspecified, we must check both masks on biarch 214 * as syscall number alone is ambiguous. */ 215 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL, 216 entry->rule.mask) && 217 audit_match_class_bits(AUDIT_CLASS_SIGNAL_32, 218 entry->rule.mask)); 219 } 220 221 switch(audit_classify_arch(arch->val)) { 222 case 0: /* native */ 223 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL, 224 entry->rule.mask)); 225 case 1: /* 32bit on biarch */ 226 return (audit_match_class_bits(AUDIT_CLASS_SIGNAL_32, 227 entry->rule.mask)); 228 default: 229 return 1; 230 } 231 } 232 #endif 233 234 /* Common user-space to kernel rule translation. */ 235 static inline struct audit_entry *audit_to_entry_common(struct audit_rule_data *rule) 236 { 237 unsigned listnr; 238 struct audit_entry *entry; 239 int i, err; 240 241 err = -EINVAL; 242 listnr = rule->flags & ~AUDIT_FILTER_PREPEND; 243 switch(listnr) { 244 default: 245 goto exit_err; 246 #ifdef CONFIG_AUDITSYSCALL 247 case AUDIT_FILTER_ENTRY: 248 pr_err("AUDIT_FILTER_ENTRY is deprecated\n"); 249 goto exit_err; 250 case AUDIT_FILTER_EXIT: 251 case AUDIT_FILTER_TASK: 252 #endif 253 case AUDIT_FILTER_USER: 254 case AUDIT_FILTER_EXCLUDE: 255 case AUDIT_FILTER_FS: 256 ; 257 } 258 if (unlikely(rule->action == AUDIT_POSSIBLE)) { 259 pr_err("AUDIT_POSSIBLE is deprecated\n"); 260 goto exit_err; 261 } 262 if (rule->action != AUDIT_NEVER && rule->action != AUDIT_ALWAYS) 263 goto exit_err; 264 if (rule->field_count > AUDIT_MAX_FIELDS) 265 goto exit_err; 266 267 err = -ENOMEM; 268 entry = audit_init_entry(rule->field_count); 269 if (!entry) 270 goto exit_err; 271 272 entry->rule.flags = rule->flags & AUDIT_FILTER_PREPEND; 273 entry->rule.listnr = listnr; 274 entry->rule.action = rule->action; 275 entry->rule.field_count = rule->field_count; 276 277 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) 278 entry->rule.mask[i] = rule->mask[i]; 279 280 for (i = 0; i < AUDIT_SYSCALL_CLASSES; i++) { 281 int bit = AUDIT_BITMASK_SIZE * 32 - i - 1; 282 __u32 *p = &entry->rule.mask[AUDIT_WORD(bit)]; 283 __u32 *class; 284 285 if (!(*p & AUDIT_BIT(bit))) 286 continue; 287 *p &= ~AUDIT_BIT(bit); 288 class = classes[i]; 289 if (class) { 290 int j; 291 for (j = 0; j < AUDIT_BITMASK_SIZE; j++) 292 entry->rule.mask[j] |= class[j]; 293 } 294 } 295 296 return entry; 297 298 exit_err: 299 return ERR_PTR(err); 300 } 301 302 static u32 audit_ops[] = 303 { 304 [Audit_equal] = AUDIT_EQUAL, 305 [Audit_not_equal] = AUDIT_NOT_EQUAL, 306 [Audit_bitmask] = AUDIT_BIT_MASK, 307 [Audit_bittest] = AUDIT_BIT_TEST, 308 [Audit_lt] = AUDIT_LESS_THAN, 309 [Audit_gt] = AUDIT_GREATER_THAN, 310 [Audit_le] = AUDIT_LESS_THAN_OR_EQUAL, 311 [Audit_ge] = AUDIT_GREATER_THAN_OR_EQUAL, 312 }; 313 314 static u32 audit_to_op(u32 op) 315 { 316 u32 n; 317 for (n = Audit_equal; n < Audit_bad && audit_ops[n] != op; n++) 318 ; 319 return n; 320 } 321 322 /* check if an audit field is valid */ 323 static int audit_field_valid(struct audit_entry *entry, struct audit_field *f) 324 { 325 switch(f->type) { 326 case AUDIT_MSGTYPE: 327 if (entry->rule.listnr != AUDIT_FILTER_EXCLUDE && 328 entry->rule.listnr != AUDIT_FILTER_USER) 329 return -EINVAL; 330 break; 331 case AUDIT_FSTYPE: 332 if (entry->rule.listnr != AUDIT_FILTER_FS) 333 return -EINVAL; 334 break; 335 } 336 337 switch(entry->rule.listnr) { 338 case AUDIT_FILTER_FS: 339 switch(f->type) { 340 case AUDIT_FSTYPE: 341 case AUDIT_FILTERKEY: 342 break; 343 default: 344 return -EINVAL; 345 } 346 } 347 348 switch(f->type) { 349 default: 350 return -EINVAL; 351 case AUDIT_UID: 352 case AUDIT_EUID: 353 case AUDIT_SUID: 354 case AUDIT_FSUID: 355 case AUDIT_LOGINUID: 356 case AUDIT_OBJ_UID: 357 case AUDIT_GID: 358 case AUDIT_EGID: 359 case AUDIT_SGID: 360 case AUDIT_FSGID: 361 case AUDIT_OBJ_GID: 362 case AUDIT_PID: 363 case AUDIT_PERS: 364 case AUDIT_MSGTYPE: 365 case AUDIT_PPID: 366 case AUDIT_DEVMAJOR: 367 case AUDIT_DEVMINOR: 368 case AUDIT_EXIT: 369 case AUDIT_SUCCESS: 370 case AUDIT_INODE: 371 case AUDIT_SESSIONID: 372 /* bit ops are only useful on syscall args */ 373 if (f->op == Audit_bitmask || f->op == Audit_bittest) 374 return -EINVAL; 375 break; 376 case AUDIT_ARG0: 377 case AUDIT_ARG1: 378 case AUDIT_ARG2: 379 case AUDIT_ARG3: 380 case AUDIT_SUBJ_USER: 381 case AUDIT_SUBJ_ROLE: 382 case AUDIT_SUBJ_TYPE: 383 case AUDIT_SUBJ_SEN: 384 case AUDIT_SUBJ_CLR: 385 case AUDIT_OBJ_USER: 386 case AUDIT_OBJ_ROLE: 387 case AUDIT_OBJ_TYPE: 388 case AUDIT_OBJ_LEV_LOW: 389 case AUDIT_OBJ_LEV_HIGH: 390 case AUDIT_WATCH: 391 case AUDIT_DIR: 392 case AUDIT_FILTERKEY: 393 break; 394 case AUDIT_LOGINUID_SET: 395 if ((f->val != 0) && (f->val != 1)) 396 return -EINVAL; 397 /* FALL THROUGH */ 398 case AUDIT_ARCH: 399 case AUDIT_FSTYPE: 400 if (f->op != Audit_not_equal && f->op != Audit_equal) 401 return -EINVAL; 402 break; 403 case AUDIT_PERM: 404 if (f->val & ~15) 405 return -EINVAL; 406 break; 407 case AUDIT_FILETYPE: 408 if (f->val & ~S_IFMT) 409 return -EINVAL; 410 break; 411 case AUDIT_FIELD_COMPARE: 412 if (f->val > AUDIT_MAX_FIELD_COMPARE) 413 return -EINVAL; 414 break; 415 case AUDIT_EXE: 416 if (f->op != Audit_not_equal && f->op != Audit_equal) 417 return -EINVAL; 418 break; 419 } 420 return 0; 421 } 422 423 /* Translate struct audit_rule_data to kernel's rule representation. */ 424 static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data, 425 size_t datasz) 426 { 427 int err = 0; 428 struct audit_entry *entry; 429 void *bufp; 430 size_t remain = datasz - sizeof(struct audit_rule_data); 431 int i; 432 char *str; 433 struct audit_fsnotify_mark *audit_mark; 434 435 entry = audit_to_entry_common(data); 436 if (IS_ERR(entry)) 437 goto exit_nofree; 438 439 bufp = data->buf; 440 for (i = 0; i < data->field_count; i++) { 441 struct audit_field *f = &entry->rule.fields[i]; 442 443 err = -EINVAL; 444 445 f->op = audit_to_op(data->fieldflags[i]); 446 if (f->op == Audit_bad) 447 goto exit_free; 448 449 f->type = data->fields[i]; 450 f->val = data->values[i]; 451 452 /* Support legacy tests for a valid loginuid */ 453 if ((f->type == AUDIT_LOGINUID) && (f->val == AUDIT_UID_UNSET)) { 454 f->type = AUDIT_LOGINUID_SET; 455 f->val = 0; 456 entry->rule.pflags |= AUDIT_LOGINUID_LEGACY; 457 } 458 459 err = audit_field_valid(entry, f); 460 if (err) 461 goto exit_free; 462 463 err = -EINVAL; 464 switch (f->type) { 465 case AUDIT_LOGINUID: 466 case AUDIT_UID: 467 case AUDIT_EUID: 468 case AUDIT_SUID: 469 case AUDIT_FSUID: 470 case AUDIT_OBJ_UID: 471 f->uid = make_kuid(current_user_ns(), f->val); 472 if (!uid_valid(f->uid)) 473 goto exit_free; 474 break; 475 case AUDIT_GID: 476 case AUDIT_EGID: 477 case AUDIT_SGID: 478 case AUDIT_FSGID: 479 case AUDIT_OBJ_GID: 480 f->gid = make_kgid(current_user_ns(), f->val); 481 if (!gid_valid(f->gid)) 482 goto exit_free; 483 break; 484 case AUDIT_ARCH: 485 entry->rule.arch_f = f; 486 break; 487 case AUDIT_SUBJ_USER: 488 case AUDIT_SUBJ_ROLE: 489 case AUDIT_SUBJ_TYPE: 490 case AUDIT_SUBJ_SEN: 491 case AUDIT_SUBJ_CLR: 492 case AUDIT_OBJ_USER: 493 case AUDIT_OBJ_ROLE: 494 case AUDIT_OBJ_TYPE: 495 case AUDIT_OBJ_LEV_LOW: 496 case AUDIT_OBJ_LEV_HIGH: 497 str = audit_unpack_string(&bufp, &remain, f->val); 498 if (IS_ERR(str)) 499 goto exit_free; 500 entry->rule.buflen += f->val; 501 502 err = security_audit_rule_init(f->type, f->op, str, 503 (void **)&f->lsm_rule); 504 /* Keep currently invalid fields around in case they 505 * become valid after a policy reload. */ 506 if (err == -EINVAL) { 507 pr_warn("audit rule for LSM \'%s\' is invalid\n", 508 str); 509 err = 0; 510 } 511 if (err) { 512 kfree(str); 513 goto exit_free; 514 } else 515 f->lsm_str = str; 516 break; 517 case AUDIT_WATCH: 518 str = audit_unpack_string(&bufp, &remain, f->val); 519 if (IS_ERR(str)) 520 goto exit_free; 521 entry->rule.buflen += f->val; 522 523 err = audit_to_watch(&entry->rule, str, f->val, f->op); 524 if (err) { 525 kfree(str); 526 goto exit_free; 527 } 528 break; 529 case AUDIT_DIR: 530 str = audit_unpack_string(&bufp, &remain, f->val); 531 if (IS_ERR(str)) 532 goto exit_free; 533 entry->rule.buflen += f->val; 534 535 err = audit_make_tree(&entry->rule, str, f->op); 536 kfree(str); 537 if (err) 538 goto exit_free; 539 break; 540 case AUDIT_INODE: 541 err = audit_to_inode(&entry->rule, f); 542 if (err) 543 goto exit_free; 544 break; 545 case AUDIT_FILTERKEY: 546 if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN) 547 goto exit_free; 548 str = audit_unpack_string(&bufp, &remain, f->val); 549 if (IS_ERR(str)) 550 goto exit_free; 551 entry->rule.buflen += f->val; 552 entry->rule.filterkey = str; 553 break; 554 case AUDIT_EXE: 555 if (entry->rule.exe || f->val > PATH_MAX) 556 goto exit_free; 557 str = audit_unpack_string(&bufp, &remain, f->val); 558 if (IS_ERR(str)) { 559 err = PTR_ERR(str); 560 goto exit_free; 561 } 562 entry->rule.buflen += f->val; 563 564 audit_mark = audit_alloc_mark(&entry->rule, str, f->val); 565 if (IS_ERR(audit_mark)) { 566 kfree(str); 567 err = PTR_ERR(audit_mark); 568 goto exit_free; 569 } 570 entry->rule.exe = audit_mark; 571 break; 572 } 573 } 574 575 if (entry->rule.inode_f && entry->rule.inode_f->op == Audit_not_equal) 576 entry->rule.inode_f = NULL; 577 578 exit_nofree: 579 return entry; 580 581 exit_free: 582 if (entry->rule.tree) 583 audit_put_tree(entry->rule.tree); /* that's the temporary one */ 584 if (entry->rule.exe) 585 audit_remove_mark(entry->rule.exe); /* that's the template one */ 586 audit_free_rule(entry); 587 return ERR_PTR(err); 588 } 589 590 /* Pack a filter field's string representation into data block. */ 591 static inline size_t audit_pack_string(void **bufp, const char *str) 592 { 593 size_t len = strlen(str); 594 595 memcpy(*bufp, str, len); 596 *bufp += len; 597 598 return len; 599 } 600 601 /* Translate kernel rule representation to struct audit_rule_data. */ 602 static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule) 603 { 604 struct audit_rule_data *data; 605 void *bufp; 606 int i; 607 608 data = kmalloc(sizeof(*data) + krule->buflen, GFP_KERNEL); 609 if (unlikely(!data)) 610 return NULL; 611 memset(data, 0, sizeof(*data)); 612 613 data->flags = krule->flags | krule->listnr; 614 data->action = krule->action; 615 data->field_count = krule->field_count; 616 bufp = data->buf; 617 for (i = 0; i < data->field_count; i++) { 618 struct audit_field *f = &krule->fields[i]; 619 620 data->fields[i] = f->type; 621 data->fieldflags[i] = audit_ops[f->op]; 622 switch(f->type) { 623 case AUDIT_SUBJ_USER: 624 case AUDIT_SUBJ_ROLE: 625 case AUDIT_SUBJ_TYPE: 626 case AUDIT_SUBJ_SEN: 627 case AUDIT_SUBJ_CLR: 628 case AUDIT_OBJ_USER: 629 case AUDIT_OBJ_ROLE: 630 case AUDIT_OBJ_TYPE: 631 case AUDIT_OBJ_LEV_LOW: 632 case AUDIT_OBJ_LEV_HIGH: 633 data->buflen += data->values[i] = 634 audit_pack_string(&bufp, f->lsm_str); 635 break; 636 case AUDIT_WATCH: 637 data->buflen += data->values[i] = 638 audit_pack_string(&bufp, 639 audit_watch_path(krule->watch)); 640 break; 641 case AUDIT_DIR: 642 data->buflen += data->values[i] = 643 audit_pack_string(&bufp, 644 audit_tree_path(krule->tree)); 645 break; 646 case AUDIT_FILTERKEY: 647 data->buflen += data->values[i] = 648 audit_pack_string(&bufp, krule->filterkey); 649 break; 650 case AUDIT_EXE: 651 data->buflen += data->values[i] = 652 audit_pack_string(&bufp, audit_mark_path(krule->exe)); 653 break; 654 case AUDIT_LOGINUID_SET: 655 if (krule->pflags & AUDIT_LOGINUID_LEGACY && !f->val) { 656 data->fields[i] = AUDIT_LOGINUID; 657 data->values[i] = AUDIT_UID_UNSET; 658 break; 659 } 660 /* fall through - if set */ 661 default: 662 data->values[i] = f->val; 663 } 664 } 665 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) data->mask[i] = krule->mask[i]; 666 667 return data; 668 } 669 670 /* Compare two rules in kernel format. Considered success if rules 671 * don't match. */ 672 static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b) 673 { 674 int i; 675 676 if (a->flags != b->flags || 677 a->pflags != b->pflags || 678 a->listnr != b->listnr || 679 a->action != b->action || 680 a->field_count != b->field_count) 681 return 1; 682 683 for (i = 0; i < a->field_count; i++) { 684 if (a->fields[i].type != b->fields[i].type || 685 a->fields[i].op != b->fields[i].op) 686 return 1; 687 688 switch(a->fields[i].type) { 689 case AUDIT_SUBJ_USER: 690 case AUDIT_SUBJ_ROLE: 691 case AUDIT_SUBJ_TYPE: 692 case AUDIT_SUBJ_SEN: 693 case AUDIT_SUBJ_CLR: 694 case AUDIT_OBJ_USER: 695 case AUDIT_OBJ_ROLE: 696 case AUDIT_OBJ_TYPE: 697 case AUDIT_OBJ_LEV_LOW: 698 case AUDIT_OBJ_LEV_HIGH: 699 if (strcmp(a->fields[i].lsm_str, b->fields[i].lsm_str)) 700 return 1; 701 break; 702 case AUDIT_WATCH: 703 if (strcmp(audit_watch_path(a->watch), 704 audit_watch_path(b->watch))) 705 return 1; 706 break; 707 case AUDIT_DIR: 708 if (strcmp(audit_tree_path(a->tree), 709 audit_tree_path(b->tree))) 710 return 1; 711 break; 712 case AUDIT_FILTERKEY: 713 /* both filterkeys exist based on above type compare */ 714 if (strcmp(a->filterkey, b->filterkey)) 715 return 1; 716 break; 717 case AUDIT_EXE: 718 /* both paths exist based on above type compare */ 719 if (strcmp(audit_mark_path(a->exe), 720 audit_mark_path(b->exe))) 721 return 1; 722 break; 723 case AUDIT_UID: 724 case AUDIT_EUID: 725 case AUDIT_SUID: 726 case AUDIT_FSUID: 727 case AUDIT_LOGINUID: 728 case AUDIT_OBJ_UID: 729 if (!uid_eq(a->fields[i].uid, b->fields[i].uid)) 730 return 1; 731 break; 732 case AUDIT_GID: 733 case AUDIT_EGID: 734 case AUDIT_SGID: 735 case AUDIT_FSGID: 736 case AUDIT_OBJ_GID: 737 if (!gid_eq(a->fields[i].gid, b->fields[i].gid)) 738 return 1; 739 break; 740 default: 741 if (a->fields[i].val != b->fields[i].val) 742 return 1; 743 } 744 } 745 746 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) 747 if (a->mask[i] != b->mask[i]) 748 return 1; 749 750 return 0; 751 } 752 753 /* Duplicate LSM field information. The lsm_rule is opaque, so must be 754 * re-initialized. */ 755 static inline int audit_dupe_lsm_field(struct audit_field *df, 756 struct audit_field *sf) 757 { 758 int ret = 0; 759 char *lsm_str; 760 761 /* our own copy of lsm_str */ 762 lsm_str = kstrdup(sf->lsm_str, GFP_KERNEL); 763 if (unlikely(!lsm_str)) 764 return -ENOMEM; 765 df->lsm_str = lsm_str; 766 767 /* our own (refreshed) copy of lsm_rule */ 768 ret = security_audit_rule_init(df->type, df->op, df->lsm_str, 769 (void **)&df->lsm_rule); 770 /* Keep currently invalid fields around in case they 771 * become valid after a policy reload. */ 772 if (ret == -EINVAL) { 773 pr_warn("audit rule for LSM \'%s\' is invalid\n", 774 df->lsm_str); 775 ret = 0; 776 } 777 778 return ret; 779 } 780 781 /* Duplicate an audit rule. This will be a deep copy with the exception 782 * of the watch - that pointer is carried over. The LSM specific fields 783 * will be updated in the copy. The point is to be able to replace the old 784 * rule with the new rule in the filterlist, then free the old rule. 785 * The rlist element is undefined; list manipulations are handled apart from 786 * the initial copy. */ 787 struct audit_entry *audit_dupe_rule(struct audit_krule *old) 788 { 789 u32 fcount = old->field_count; 790 struct audit_entry *entry; 791 struct audit_krule *new; 792 char *fk; 793 int i, err = 0; 794 795 entry = audit_init_entry(fcount); 796 if (unlikely(!entry)) 797 return ERR_PTR(-ENOMEM); 798 799 new = &entry->rule; 800 new->flags = old->flags; 801 new->pflags = old->pflags; 802 new->listnr = old->listnr; 803 new->action = old->action; 804 for (i = 0; i < AUDIT_BITMASK_SIZE; i++) 805 new->mask[i] = old->mask[i]; 806 new->prio = old->prio; 807 new->buflen = old->buflen; 808 new->inode_f = old->inode_f; 809 new->field_count = old->field_count; 810 811 /* 812 * note that we are OK with not refcounting here; audit_match_tree() 813 * never dereferences tree and we can't get false positives there 814 * since we'd have to have rule gone from the list *and* removed 815 * before the chunks found by lookup had been allocated, i.e. before 816 * the beginning of list scan. 817 */ 818 new->tree = old->tree; 819 memcpy(new->fields, old->fields, sizeof(struct audit_field) * fcount); 820 821 /* deep copy this information, updating the lsm_rule fields, because 822 * the originals will all be freed when the old rule is freed. */ 823 for (i = 0; i < fcount; i++) { 824 switch (new->fields[i].type) { 825 case AUDIT_SUBJ_USER: 826 case AUDIT_SUBJ_ROLE: 827 case AUDIT_SUBJ_TYPE: 828 case AUDIT_SUBJ_SEN: 829 case AUDIT_SUBJ_CLR: 830 case AUDIT_OBJ_USER: 831 case AUDIT_OBJ_ROLE: 832 case AUDIT_OBJ_TYPE: 833 case AUDIT_OBJ_LEV_LOW: 834 case AUDIT_OBJ_LEV_HIGH: 835 err = audit_dupe_lsm_field(&new->fields[i], 836 &old->fields[i]); 837 break; 838 case AUDIT_FILTERKEY: 839 fk = kstrdup(old->filterkey, GFP_KERNEL); 840 if (unlikely(!fk)) 841 err = -ENOMEM; 842 else 843 new->filterkey = fk; 844 break; 845 case AUDIT_EXE: 846 err = audit_dupe_exe(new, old); 847 break; 848 } 849 if (err) { 850 if (new->exe) 851 audit_remove_mark(new->exe); 852 audit_free_rule(entry); 853 return ERR_PTR(err); 854 } 855 } 856 857 if (old->watch) { 858 audit_get_watch(old->watch); 859 new->watch = old->watch; 860 } 861 862 return entry; 863 } 864 865 /* Find an existing audit rule. 866 * Caller must hold audit_filter_mutex to prevent stale rule data. */ 867 static struct audit_entry *audit_find_rule(struct audit_entry *entry, 868 struct list_head **p) 869 { 870 struct audit_entry *e, *found = NULL; 871 struct list_head *list; 872 int h; 873 874 if (entry->rule.inode_f) { 875 h = audit_hash_ino(entry->rule.inode_f->val); 876 *p = list = &audit_inode_hash[h]; 877 } else if (entry->rule.watch) { 878 /* we don't know the inode number, so must walk entire hash */ 879 for (h = 0; h < AUDIT_INODE_BUCKETS; h++) { 880 list = &audit_inode_hash[h]; 881 list_for_each_entry(e, list, list) 882 if (!audit_compare_rule(&entry->rule, &e->rule)) { 883 found = e; 884 goto out; 885 } 886 } 887 goto out; 888 } else { 889 *p = list = &audit_filter_list[entry->rule.listnr]; 890 } 891 892 list_for_each_entry(e, list, list) 893 if (!audit_compare_rule(&entry->rule, &e->rule)) { 894 found = e; 895 goto out; 896 } 897 898 out: 899 return found; 900 } 901 902 static u64 prio_low = ~0ULL/2; 903 static u64 prio_high = ~0ULL/2 - 1; 904 905 /* Add rule to given filterlist if not a duplicate. */ 906 static inline int audit_add_rule(struct audit_entry *entry) 907 { 908 struct audit_entry *e; 909 struct audit_watch *watch = entry->rule.watch; 910 struct audit_tree *tree = entry->rule.tree; 911 struct list_head *list; 912 int err = 0; 913 #ifdef CONFIG_AUDITSYSCALL 914 int dont_count = 0; 915 916 /* If any of these, don't count towards total */ 917 switch(entry->rule.listnr) { 918 case AUDIT_FILTER_USER: 919 case AUDIT_FILTER_EXCLUDE: 920 case AUDIT_FILTER_FS: 921 dont_count = 1; 922 } 923 #endif 924 925 mutex_lock(&audit_filter_mutex); 926 e = audit_find_rule(entry, &list); 927 if (e) { 928 mutex_unlock(&audit_filter_mutex); 929 err = -EEXIST; 930 /* normally audit_add_tree_rule() will free it on failure */ 931 if (tree) 932 audit_put_tree(tree); 933 return err; 934 } 935 936 if (watch) { 937 /* audit_filter_mutex is dropped and re-taken during this call */ 938 err = audit_add_watch(&entry->rule, &list); 939 if (err) { 940 mutex_unlock(&audit_filter_mutex); 941 /* 942 * normally audit_add_tree_rule() will free it 943 * on failure 944 */ 945 if (tree) 946 audit_put_tree(tree); 947 return err; 948 } 949 } 950 if (tree) { 951 err = audit_add_tree_rule(&entry->rule); 952 if (err) { 953 mutex_unlock(&audit_filter_mutex); 954 return err; 955 } 956 } 957 958 entry->rule.prio = ~0ULL; 959 if (entry->rule.listnr == AUDIT_FILTER_EXIT) { 960 if (entry->rule.flags & AUDIT_FILTER_PREPEND) 961 entry->rule.prio = ++prio_high; 962 else 963 entry->rule.prio = --prio_low; 964 } 965 966 if (entry->rule.flags & AUDIT_FILTER_PREPEND) { 967 list_add(&entry->rule.list, 968 &audit_rules_list[entry->rule.listnr]); 969 list_add_rcu(&entry->list, list); 970 entry->rule.flags &= ~AUDIT_FILTER_PREPEND; 971 } else { 972 list_add_tail(&entry->rule.list, 973 &audit_rules_list[entry->rule.listnr]); 974 list_add_tail_rcu(&entry->list, list); 975 } 976 #ifdef CONFIG_AUDITSYSCALL 977 if (!dont_count) 978 audit_n_rules++; 979 980 if (!audit_match_signal(entry)) 981 audit_signals++; 982 #endif 983 mutex_unlock(&audit_filter_mutex); 984 985 return err; 986 } 987 988 /* Remove an existing rule from filterlist. */ 989 int audit_del_rule(struct audit_entry *entry) 990 { 991 struct audit_entry *e; 992 struct audit_tree *tree = entry->rule.tree; 993 struct list_head *list; 994 int ret = 0; 995 #ifdef CONFIG_AUDITSYSCALL 996 int dont_count = 0; 997 998 /* If any of these, don't count towards total */ 999 switch(entry->rule.listnr) { 1000 case AUDIT_FILTER_USER: 1001 case AUDIT_FILTER_EXCLUDE: 1002 case AUDIT_FILTER_FS: 1003 dont_count = 1; 1004 } 1005 #endif 1006 1007 mutex_lock(&audit_filter_mutex); 1008 e = audit_find_rule(entry, &list); 1009 if (!e) { 1010 ret = -ENOENT; 1011 goto out; 1012 } 1013 1014 if (e->rule.watch) 1015 audit_remove_watch_rule(&e->rule); 1016 1017 if (e->rule.tree) 1018 audit_remove_tree_rule(&e->rule); 1019 1020 if (e->rule.exe) 1021 audit_remove_mark_rule(&e->rule); 1022 1023 #ifdef CONFIG_AUDITSYSCALL 1024 if (!dont_count) 1025 audit_n_rules--; 1026 1027 if (!audit_match_signal(entry)) 1028 audit_signals--; 1029 #endif 1030 1031 list_del_rcu(&e->list); 1032 list_del(&e->rule.list); 1033 call_rcu(&e->rcu, audit_free_rule_rcu); 1034 1035 out: 1036 mutex_unlock(&audit_filter_mutex); 1037 1038 if (tree) 1039 audit_put_tree(tree); /* that's the temporary one */ 1040 1041 return ret; 1042 } 1043 1044 /* List rules using struct audit_rule_data. */ 1045 static void audit_list_rules(int seq, struct sk_buff_head *q) 1046 { 1047 struct sk_buff *skb; 1048 struct audit_krule *r; 1049 int i; 1050 1051 /* This is a blocking read, so use audit_filter_mutex instead of rcu 1052 * iterator to sync with list writers. */ 1053 for (i=0; i<AUDIT_NR_FILTERS; i++) { 1054 list_for_each_entry(r, &audit_rules_list[i], list) { 1055 struct audit_rule_data *data; 1056 1057 data = audit_krule_to_data(r); 1058 if (unlikely(!data)) 1059 break; 1060 skb = audit_make_reply(seq, AUDIT_LIST_RULES, 0, 1, 1061 data, 1062 sizeof(*data) + data->buflen); 1063 if (skb) 1064 skb_queue_tail(q, skb); 1065 kfree(data); 1066 } 1067 } 1068 skb = audit_make_reply(seq, AUDIT_LIST_RULES, 1, 1, NULL, 0); 1069 if (skb) 1070 skb_queue_tail(q, skb); 1071 } 1072 1073 /* Log rule additions and removals */ 1074 static void audit_log_rule_change(char *action, struct audit_krule *rule, int res) 1075 { 1076 struct audit_buffer *ab; 1077 1078 if (!audit_enabled) 1079 return; 1080 1081 ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_CONFIG_CHANGE); 1082 if (!ab) 1083 return; 1084 audit_log_session_info(ab); 1085 audit_log_task_context(ab); 1086 audit_log_format(ab, " op=%s", action); 1087 audit_log_key(ab, rule->filterkey); 1088 audit_log_format(ab, " list=%d res=%d", rule->listnr, res); 1089 audit_log_end(ab); 1090 } 1091 1092 /** 1093 * audit_rule_change - apply all rules to the specified message type 1094 * @type: audit message type 1095 * @seq: netlink audit message sequence (serial) number 1096 * @data: payload data 1097 * @datasz: size of payload data 1098 */ 1099 int audit_rule_change(int type, int seq, void *data, size_t datasz) 1100 { 1101 int err = 0; 1102 struct audit_entry *entry; 1103 1104 switch (type) { 1105 case AUDIT_ADD_RULE: 1106 entry = audit_data_to_entry(data, datasz); 1107 if (IS_ERR(entry)) 1108 return PTR_ERR(entry); 1109 err = audit_add_rule(entry); 1110 audit_log_rule_change("add_rule", &entry->rule, !err); 1111 break; 1112 case AUDIT_DEL_RULE: 1113 entry = audit_data_to_entry(data, datasz); 1114 if (IS_ERR(entry)) 1115 return PTR_ERR(entry); 1116 err = audit_del_rule(entry); 1117 audit_log_rule_change("remove_rule", &entry->rule, !err); 1118 break; 1119 default: 1120 WARN_ON(1); 1121 return -EINVAL; 1122 } 1123 1124 if (err || type == AUDIT_DEL_RULE) { 1125 if (entry->rule.exe) 1126 audit_remove_mark(entry->rule.exe); 1127 audit_free_rule(entry); 1128 } 1129 1130 return err; 1131 } 1132 1133 /** 1134 * audit_list_rules_send - list the audit rules 1135 * @request_skb: skb of request we are replying to (used to target the reply) 1136 * @seq: netlink audit message sequence (serial) number 1137 */ 1138 int audit_list_rules_send(struct sk_buff *request_skb, int seq) 1139 { 1140 u32 portid = NETLINK_CB(request_skb).portid; 1141 struct net *net = sock_net(NETLINK_CB(request_skb).sk); 1142 struct task_struct *tsk; 1143 struct audit_netlink_list *dest; 1144 int err = 0; 1145 1146 /* We can't just spew out the rules here because we might fill 1147 * the available socket buffer space and deadlock waiting for 1148 * auditctl to read from it... which isn't ever going to 1149 * happen if we're actually running in the context of auditctl 1150 * trying to _send_ the stuff */ 1151 1152 dest = kmalloc(sizeof(struct audit_netlink_list), GFP_KERNEL); 1153 if (!dest) 1154 return -ENOMEM; 1155 dest->net = get_net(net); 1156 dest->portid = portid; 1157 skb_queue_head_init(&dest->q); 1158 1159 mutex_lock(&audit_filter_mutex); 1160 audit_list_rules(seq, &dest->q); 1161 mutex_unlock(&audit_filter_mutex); 1162 1163 tsk = kthread_run(audit_send_list, dest, "audit_send_list"); 1164 if (IS_ERR(tsk)) { 1165 skb_queue_purge(&dest->q); 1166 kfree(dest); 1167 err = PTR_ERR(tsk); 1168 } 1169 1170 return err; 1171 } 1172 1173 int audit_comparator(u32 left, u32 op, u32 right) 1174 { 1175 switch (op) { 1176 case Audit_equal: 1177 return (left == right); 1178 case Audit_not_equal: 1179 return (left != right); 1180 case Audit_lt: 1181 return (left < right); 1182 case Audit_le: 1183 return (left <= right); 1184 case Audit_gt: 1185 return (left > right); 1186 case Audit_ge: 1187 return (left >= right); 1188 case Audit_bitmask: 1189 return (left & right); 1190 case Audit_bittest: 1191 return ((left & right) == right); 1192 default: 1193 BUG(); 1194 return 0; 1195 } 1196 } 1197 1198 int audit_uid_comparator(kuid_t left, u32 op, kuid_t right) 1199 { 1200 switch (op) { 1201 case Audit_equal: 1202 return uid_eq(left, right); 1203 case Audit_not_equal: 1204 return !uid_eq(left, right); 1205 case Audit_lt: 1206 return uid_lt(left, right); 1207 case Audit_le: 1208 return uid_lte(left, right); 1209 case Audit_gt: 1210 return uid_gt(left, right); 1211 case Audit_ge: 1212 return uid_gte(left, right); 1213 case Audit_bitmask: 1214 case Audit_bittest: 1215 default: 1216 BUG(); 1217 return 0; 1218 } 1219 } 1220 1221 int audit_gid_comparator(kgid_t left, u32 op, kgid_t right) 1222 { 1223 switch (op) { 1224 case Audit_equal: 1225 return gid_eq(left, right); 1226 case Audit_not_equal: 1227 return !gid_eq(left, right); 1228 case Audit_lt: 1229 return gid_lt(left, right); 1230 case Audit_le: 1231 return gid_lte(left, right); 1232 case Audit_gt: 1233 return gid_gt(left, right); 1234 case Audit_ge: 1235 return gid_gte(left, right); 1236 case Audit_bitmask: 1237 case Audit_bittest: 1238 default: 1239 BUG(); 1240 return 0; 1241 } 1242 } 1243 1244 /** 1245 * parent_len - find the length of the parent portion of a pathname 1246 * @path: pathname of which to determine length 1247 */ 1248 int parent_len(const char *path) 1249 { 1250 int plen; 1251 const char *p; 1252 1253 plen = strlen(path); 1254 1255 if (plen == 0) 1256 return plen; 1257 1258 /* disregard trailing slashes */ 1259 p = path + plen - 1; 1260 while ((*p == '/') && (p > path)) 1261 p--; 1262 1263 /* walk backward until we find the next slash or hit beginning */ 1264 while ((*p != '/') && (p > path)) 1265 p--; 1266 1267 /* did we find a slash? Then increment to include it in path */ 1268 if (*p == '/') 1269 p++; 1270 1271 return p - path; 1272 } 1273 1274 /** 1275 * audit_compare_dname_path - compare given dentry name with last component in 1276 * given path. Return of 0 indicates a match. 1277 * @dname: dentry name that we're comparing 1278 * @path: full pathname that we're comparing 1279 * @parentlen: length of the parent if known. Passing in AUDIT_NAME_FULL 1280 * here indicates that we must compute this value. 1281 */ 1282 int audit_compare_dname_path(const struct qstr *dname, const char *path, int parentlen) 1283 { 1284 int dlen, pathlen; 1285 const char *p; 1286 1287 dlen = dname->len; 1288 pathlen = strlen(path); 1289 if (pathlen < dlen) 1290 return 1; 1291 1292 parentlen = parentlen == AUDIT_NAME_FULL ? parent_len(path) : parentlen; 1293 if (pathlen - parentlen != dlen) 1294 return 1; 1295 1296 p = path + parentlen; 1297 1298 return strncmp(p, dname->name, dlen); 1299 } 1300 1301 int audit_filter(int msgtype, unsigned int listtype) 1302 { 1303 struct audit_entry *e; 1304 int ret = 1; /* Audit by default */ 1305 1306 rcu_read_lock(); 1307 list_for_each_entry_rcu(e, &audit_filter_list[listtype], list) { 1308 int i, result = 0; 1309 1310 for (i = 0; i < e->rule.field_count; i++) { 1311 struct audit_field *f = &e->rule.fields[i]; 1312 pid_t pid; 1313 u32 sid; 1314 1315 switch (f->type) { 1316 case AUDIT_PID: 1317 pid = task_pid_nr(current); 1318 result = audit_comparator(pid, f->op, f->val); 1319 break; 1320 case AUDIT_UID: 1321 result = audit_uid_comparator(current_uid(), f->op, f->uid); 1322 break; 1323 case AUDIT_GID: 1324 result = audit_gid_comparator(current_gid(), f->op, f->gid); 1325 break; 1326 case AUDIT_LOGINUID: 1327 result = audit_uid_comparator(audit_get_loginuid(current), 1328 f->op, f->uid); 1329 break; 1330 case AUDIT_LOGINUID_SET: 1331 result = audit_comparator(audit_loginuid_set(current), 1332 f->op, f->val); 1333 break; 1334 case AUDIT_MSGTYPE: 1335 result = audit_comparator(msgtype, f->op, f->val); 1336 break; 1337 case AUDIT_SUBJ_USER: 1338 case AUDIT_SUBJ_ROLE: 1339 case AUDIT_SUBJ_TYPE: 1340 case AUDIT_SUBJ_SEN: 1341 case AUDIT_SUBJ_CLR: 1342 if (f->lsm_rule) { 1343 security_task_getsecid(current, &sid); 1344 result = security_audit_rule_match(sid, 1345 f->type, f->op, f->lsm_rule); 1346 } 1347 break; 1348 case AUDIT_EXE: 1349 result = audit_exe_compare(current, e->rule.exe); 1350 if (f->op == Audit_not_equal) 1351 result = !result; 1352 break; 1353 default: 1354 goto unlock_and_return; 1355 } 1356 if (result < 0) /* error */ 1357 goto unlock_and_return; 1358 if (!result) 1359 break; 1360 } 1361 if (result > 0) { 1362 if (e->rule.action == AUDIT_NEVER || listtype == AUDIT_FILTER_EXCLUDE) 1363 ret = 0; 1364 break; 1365 } 1366 } 1367 unlock_and_return: 1368 rcu_read_unlock(); 1369 return ret; 1370 } 1371 1372 static int update_lsm_rule(struct audit_krule *r) 1373 { 1374 struct audit_entry *entry = container_of(r, struct audit_entry, rule); 1375 struct audit_entry *nentry; 1376 int err = 0; 1377 1378 if (!security_audit_rule_known(r)) 1379 return 0; 1380 1381 nentry = audit_dupe_rule(r); 1382 if (entry->rule.exe) 1383 audit_remove_mark(entry->rule.exe); 1384 if (IS_ERR(nentry)) { 1385 /* save the first error encountered for the 1386 * return value */ 1387 err = PTR_ERR(nentry); 1388 audit_panic("error updating LSM filters"); 1389 if (r->watch) 1390 list_del(&r->rlist); 1391 list_del_rcu(&entry->list); 1392 list_del(&r->list); 1393 } else { 1394 if (r->watch || r->tree) 1395 list_replace_init(&r->rlist, &nentry->rule.rlist); 1396 list_replace_rcu(&entry->list, &nentry->list); 1397 list_replace(&r->list, &nentry->rule.list); 1398 } 1399 call_rcu(&entry->rcu, audit_free_rule_rcu); 1400 1401 return err; 1402 } 1403 1404 /* This function will re-initialize the lsm_rule field of all applicable rules. 1405 * It will traverse the filter lists serarching for rules that contain LSM 1406 * specific filter fields. When such a rule is found, it is copied, the 1407 * LSM field is re-initialized, and the old rule is replaced with the 1408 * updated rule. */ 1409 int audit_update_lsm_rules(void) 1410 { 1411 struct audit_krule *r, *n; 1412 int i, err = 0; 1413 1414 /* audit_filter_mutex synchronizes the writers */ 1415 mutex_lock(&audit_filter_mutex); 1416 1417 for (i = 0; i < AUDIT_NR_FILTERS; i++) { 1418 list_for_each_entry_safe(r, n, &audit_rules_list[i], list) { 1419 int res = update_lsm_rule(r); 1420 if (!err) 1421 err = res; 1422 } 1423 } 1424 mutex_unlock(&audit_filter_mutex); 1425 1426 return err; 1427 } 1428