1 /* 2 * Copyright (C) 2008 IBM Corporation 3 * Author: Mimi Zohar <zohar@us.ibm.com> 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License as published by 7 * the Free Software Foundation, version 2 of the License. 8 * 9 * ima_policy.c 10 * - initialize default measure policy rules 11 * 12 */ 13 #include <linux/module.h> 14 #include <linux/list.h> 15 #include <linux/security.h> 16 #include <linux/magic.h> 17 #include <linux/parser.h> 18 #include <linux/slab.h> 19 #include <linux/genhd.h> 20 21 #include "ima.h" 22 23 /* flags definitions */ 24 #define IMA_FUNC 0x0001 25 #define IMA_MASK 0x0002 26 #define IMA_FSMAGIC 0x0004 27 #define IMA_UID 0x0008 28 #define IMA_FOWNER 0x0010 29 #define IMA_FSUUID 0x0020 30 31 #define UNKNOWN 0 32 #define MEASURE 0x0001 /* same as IMA_MEASURE */ 33 #define DONT_MEASURE 0x0002 34 #define APPRAISE 0x0004 /* same as IMA_APPRAISE */ 35 #define DONT_APPRAISE 0x0008 36 #define AUDIT 0x0040 37 38 #define MAX_LSM_RULES 6 39 enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE, 40 LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE 41 }; 42 43 struct ima_rule_entry { 44 struct list_head list; 45 int action; 46 unsigned int flags; 47 enum ima_hooks func; 48 int mask; 49 unsigned long fsmagic; 50 u8 fsuuid[16]; 51 kuid_t uid; 52 kuid_t fowner; 53 struct { 54 void *rule; /* LSM file metadata specific */ 55 void *args_p; /* audit value */ 56 int type; /* audit type */ 57 } lsm[MAX_LSM_RULES]; 58 }; 59 60 /* 61 * Without LSM specific knowledge, the default policy can only be 62 * written in terms of .action, .func, .mask, .fsmagic, .uid, and .fowner 63 */ 64 65 /* 66 * The minimum rule set to allow for full TCB coverage. Measures all files 67 * opened or mmap for exec and everything read by root. Dangerous because 68 * normal users can easily run the machine out of memory simply building 69 * and running executables. 70 */ 71 static struct ima_rule_entry default_rules[] = { 72 {.action = DONT_MEASURE,.fsmagic = PROC_SUPER_MAGIC,.flags = IMA_FSMAGIC}, 73 {.action = DONT_MEASURE,.fsmagic = SYSFS_MAGIC,.flags = IMA_FSMAGIC}, 74 {.action = DONT_MEASURE,.fsmagic = DEBUGFS_MAGIC,.flags = IMA_FSMAGIC}, 75 {.action = DONT_MEASURE,.fsmagic = TMPFS_MAGIC,.flags = IMA_FSMAGIC}, 76 {.action = DONT_MEASURE,.fsmagic = DEVPTS_SUPER_MAGIC,.flags = IMA_FSMAGIC}, 77 {.action = DONT_MEASURE,.fsmagic = BINFMTFS_MAGIC,.flags = IMA_FSMAGIC}, 78 {.action = DONT_MEASURE,.fsmagic = SECURITYFS_MAGIC,.flags = IMA_FSMAGIC}, 79 {.action = DONT_MEASURE,.fsmagic = SELINUX_MAGIC,.flags = IMA_FSMAGIC}, 80 {.action = MEASURE,.func = MMAP_CHECK,.mask = MAY_EXEC, 81 .flags = IMA_FUNC | IMA_MASK}, 82 {.action = MEASURE,.func = BPRM_CHECK,.mask = MAY_EXEC, 83 .flags = IMA_FUNC | IMA_MASK}, 84 {.action = MEASURE,.func = FILE_CHECK,.mask = MAY_READ,.uid = GLOBAL_ROOT_UID, 85 .flags = IMA_FUNC | IMA_MASK | IMA_UID}, 86 {.action = MEASURE,.func = MODULE_CHECK, .flags = IMA_FUNC}, 87 }; 88 89 static struct ima_rule_entry default_appraise_rules[] = { 90 {.action = DONT_APPRAISE,.fsmagic = PROC_SUPER_MAGIC,.flags = IMA_FSMAGIC}, 91 {.action = DONT_APPRAISE,.fsmagic = SYSFS_MAGIC,.flags = IMA_FSMAGIC}, 92 {.action = DONT_APPRAISE,.fsmagic = DEBUGFS_MAGIC,.flags = IMA_FSMAGIC}, 93 {.action = DONT_APPRAISE,.fsmagic = TMPFS_MAGIC,.flags = IMA_FSMAGIC}, 94 {.action = DONT_APPRAISE,.fsmagic = RAMFS_MAGIC,.flags = IMA_FSMAGIC}, 95 {.action = DONT_APPRAISE,.fsmagic = DEVPTS_SUPER_MAGIC,.flags = IMA_FSMAGIC}, 96 {.action = DONT_APPRAISE,.fsmagic = BINFMTFS_MAGIC,.flags = IMA_FSMAGIC}, 97 {.action = DONT_APPRAISE,.fsmagic = SECURITYFS_MAGIC,.flags = IMA_FSMAGIC}, 98 {.action = DONT_APPRAISE,.fsmagic = SELINUX_MAGIC,.flags = IMA_FSMAGIC}, 99 {.action = DONT_APPRAISE,.fsmagic = CGROUP_SUPER_MAGIC,.flags = IMA_FSMAGIC}, 100 {.action = APPRAISE,.fowner = GLOBAL_ROOT_UID,.flags = IMA_FOWNER}, 101 }; 102 103 static LIST_HEAD(ima_default_rules); 104 static LIST_HEAD(ima_policy_rules); 105 static struct list_head *ima_rules; 106 107 static DEFINE_MUTEX(ima_rules_mutex); 108 109 static bool ima_use_tcb __initdata; 110 static int __init default_measure_policy_setup(char *str) 111 { 112 ima_use_tcb = 1; 113 return 1; 114 } 115 __setup("ima_tcb", default_measure_policy_setup); 116 117 static bool ima_use_appraise_tcb __initdata; 118 static int __init default_appraise_policy_setup(char *str) 119 { 120 ima_use_appraise_tcb = 1; 121 return 1; 122 } 123 __setup("ima_appraise_tcb", default_appraise_policy_setup); 124 125 /* 126 * Although the IMA policy does not change, the LSM policy can be 127 * reloaded, leaving the IMA LSM based rules referring to the old, 128 * stale LSM policy. 129 * 130 * Update the IMA LSM based rules to reflect the reloaded LSM policy. 131 * We assume the rules still exist; and BUG_ON() if they don't. 132 */ 133 static void ima_lsm_update_rules(void) 134 { 135 struct ima_rule_entry *entry, *tmp; 136 int result; 137 int i; 138 139 mutex_lock(&ima_rules_mutex); 140 list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) { 141 for (i = 0; i < MAX_LSM_RULES; i++) { 142 if (!entry->lsm[i].rule) 143 continue; 144 result = security_filter_rule_init(entry->lsm[i].type, 145 Audit_equal, 146 entry->lsm[i].args_p, 147 &entry->lsm[i].rule); 148 BUG_ON(!entry->lsm[i].rule); 149 } 150 } 151 mutex_unlock(&ima_rules_mutex); 152 } 153 154 /** 155 * ima_match_rules - determine whether an inode matches the measure rule. 156 * @rule: a pointer to a rule 157 * @inode: a pointer to an inode 158 * @func: LIM hook identifier 159 * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC) 160 * 161 * Returns true on rule match, false on failure. 162 */ 163 static bool ima_match_rules(struct ima_rule_entry *rule, 164 struct inode *inode, enum ima_hooks func, int mask) 165 { 166 struct task_struct *tsk = current; 167 const struct cred *cred = current_cred(); 168 int i; 169 170 if ((rule->flags & IMA_FUNC) && rule->func != func) 171 return false; 172 if ((rule->flags & IMA_MASK) && rule->mask != mask) 173 return false; 174 if ((rule->flags & IMA_FSMAGIC) 175 && rule->fsmagic != inode->i_sb->s_magic) 176 return false; 177 if ((rule->flags & IMA_FSUUID) && 178 memcmp(rule->fsuuid, inode->i_sb->s_uuid, sizeof(rule->fsuuid))) 179 return false; 180 if ((rule->flags & IMA_UID) && !uid_eq(rule->uid, cred->uid)) 181 return false; 182 if ((rule->flags & IMA_FOWNER) && !uid_eq(rule->fowner, inode->i_uid)) 183 return false; 184 for (i = 0; i < MAX_LSM_RULES; i++) { 185 int rc = 0; 186 u32 osid, sid; 187 int retried = 0; 188 189 if (!rule->lsm[i].rule) 190 continue; 191 retry: 192 switch (i) { 193 case LSM_OBJ_USER: 194 case LSM_OBJ_ROLE: 195 case LSM_OBJ_TYPE: 196 security_inode_getsecid(inode, &osid); 197 rc = security_filter_rule_match(osid, 198 rule->lsm[i].type, 199 Audit_equal, 200 rule->lsm[i].rule, 201 NULL); 202 break; 203 case LSM_SUBJ_USER: 204 case LSM_SUBJ_ROLE: 205 case LSM_SUBJ_TYPE: 206 security_task_getsecid(tsk, &sid); 207 rc = security_filter_rule_match(sid, 208 rule->lsm[i].type, 209 Audit_equal, 210 rule->lsm[i].rule, 211 NULL); 212 default: 213 break; 214 } 215 if ((rc < 0) && (!retried)) { 216 retried = 1; 217 ima_lsm_update_rules(); 218 goto retry; 219 } 220 if (!rc) 221 return false; 222 } 223 return true; 224 } 225 226 /* 227 * In addition to knowing that we need to appraise the file in general, 228 * we need to differentiate between calling hooks, for hook specific rules. 229 */ 230 static int get_subaction(struct ima_rule_entry *rule, int func) 231 { 232 if (!(rule->flags & IMA_FUNC)) 233 return IMA_FILE_APPRAISE; 234 235 switch(func) { 236 case MMAP_CHECK: 237 return IMA_MMAP_APPRAISE; 238 case BPRM_CHECK: 239 return IMA_BPRM_APPRAISE; 240 case MODULE_CHECK: 241 return IMA_MODULE_APPRAISE; 242 case FILE_CHECK: 243 default: 244 return IMA_FILE_APPRAISE; 245 } 246 } 247 248 /** 249 * ima_match_policy - decision based on LSM and other conditions 250 * @inode: pointer to an inode for which the policy decision is being made 251 * @func: IMA hook identifier 252 * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC) 253 * 254 * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type) 255 * conditions. 256 * 257 * (There is no need for locking when walking the policy list, 258 * as elements in the list are never deleted, nor does the list 259 * change.) 260 */ 261 int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask, 262 int flags) 263 { 264 struct ima_rule_entry *entry; 265 int action = 0, actmask = flags | (flags << 1); 266 267 list_for_each_entry(entry, ima_rules, list) { 268 269 if (!(entry->action & actmask)) 270 continue; 271 272 if (!ima_match_rules(entry, inode, func, mask)) 273 continue; 274 275 action |= entry->flags & IMA_ACTION_FLAGS; 276 277 action |= entry->action & IMA_DO_MASK; 278 if (entry->action & IMA_APPRAISE) 279 action |= get_subaction(entry, func); 280 281 if (entry->action & IMA_DO_MASK) 282 actmask &= ~(entry->action | entry->action << 1); 283 else 284 actmask &= ~(entry->action | entry->action >> 1); 285 286 if (!actmask) 287 break; 288 } 289 290 return action; 291 } 292 293 /** 294 * ima_init_policy - initialize the default measure rules. 295 * 296 * ima_rules points to either the ima_default_rules or the 297 * the new ima_policy_rules. 298 */ 299 void __init ima_init_policy(void) 300 { 301 int i, measure_entries, appraise_entries; 302 303 /* if !ima_use_tcb set entries = 0 so we load NO default rules */ 304 measure_entries = ima_use_tcb ? ARRAY_SIZE(default_rules) : 0; 305 appraise_entries = ima_use_appraise_tcb ? 306 ARRAY_SIZE(default_appraise_rules) : 0; 307 308 for (i = 0; i < measure_entries + appraise_entries; i++) { 309 if (i < measure_entries) 310 list_add_tail(&default_rules[i].list, 311 &ima_default_rules); 312 else { 313 int j = i - measure_entries; 314 315 list_add_tail(&default_appraise_rules[j].list, 316 &ima_default_rules); 317 } 318 } 319 320 ima_rules = &ima_default_rules; 321 } 322 323 /** 324 * ima_update_policy - update default_rules with new measure rules 325 * 326 * Called on file .release to update the default rules with a complete new 327 * policy. Once updated, the policy is locked, no additional rules can be 328 * added to the policy. 329 */ 330 void ima_update_policy(void) 331 { 332 const char *op = "policy_update"; 333 const char *cause = "already exists"; 334 int result = 1; 335 int audit_info = 0; 336 337 if (ima_rules == &ima_default_rules) { 338 ima_rules = &ima_policy_rules; 339 cause = "complete"; 340 result = 0; 341 } 342 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, 343 NULL, op, cause, result, audit_info); 344 } 345 346 enum { 347 Opt_err = -1, 348 Opt_measure = 1, Opt_dont_measure, 349 Opt_appraise, Opt_dont_appraise, 350 Opt_audit, 351 Opt_obj_user, Opt_obj_role, Opt_obj_type, 352 Opt_subj_user, Opt_subj_role, Opt_subj_type, 353 Opt_func, Opt_mask, Opt_fsmagic, Opt_uid, Opt_fowner, 354 Opt_appraise_type, Opt_fsuuid 355 }; 356 357 static match_table_t policy_tokens = { 358 {Opt_measure, "measure"}, 359 {Opt_dont_measure, "dont_measure"}, 360 {Opt_appraise, "appraise"}, 361 {Opt_dont_appraise, "dont_appraise"}, 362 {Opt_audit, "audit"}, 363 {Opt_obj_user, "obj_user=%s"}, 364 {Opt_obj_role, "obj_role=%s"}, 365 {Opt_obj_type, "obj_type=%s"}, 366 {Opt_subj_user, "subj_user=%s"}, 367 {Opt_subj_role, "subj_role=%s"}, 368 {Opt_subj_type, "subj_type=%s"}, 369 {Opt_func, "func=%s"}, 370 {Opt_mask, "mask=%s"}, 371 {Opt_fsmagic, "fsmagic=%s"}, 372 {Opt_fsuuid, "fsuuid=%s"}, 373 {Opt_uid, "uid=%s"}, 374 {Opt_fowner, "fowner=%s"}, 375 {Opt_appraise_type, "appraise_type=%s"}, 376 {Opt_err, NULL} 377 }; 378 379 static int ima_lsm_rule_init(struct ima_rule_entry *entry, 380 substring_t *args, int lsm_rule, int audit_type) 381 { 382 int result; 383 384 if (entry->lsm[lsm_rule].rule) 385 return -EINVAL; 386 387 entry->lsm[lsm_rule].args_p = match_strdup(args); 388 if (!entry->lsm[lsm_rule].args_p) 389 return -ENOMEM; 390 391 entry->lsm[lsm_rule].type = audit_type; 392 result = security_filter_rule_init(entry->lsm[lsm_rule].type, 393 Audit_equal, 394 entry->lsm[lsm_rule].args_p, 395 &entry->lsm[lsm_rule].rule); 396 if (!entry->lsm[lsm_rule].rule) { 397 kfree(entry->lsm[lsm_rule].args_p); 398 return -EINVAL; 399 } 400 401 return result; 402 } 403 404 static void ima_log_string(struct audit_buffer *ab, char *key, char *value) 405 { 406 audit_log_format(ab, "%s=", key); 407 audit_log_untrustedstring(ab, value); 408 audit_log_format(ab, " "); 409 } 410 411 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) 412 { 413 struct audit_buffer *ab; 414 char *p; 415 int result = 0; 416 417 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE); 418 419 entry->uid = INVALID_UID; 420 entry->fowner = INVALID_UID; 421 entry->action = UNKNOWN; 422 while ((p = strsep(&rule, " \t")) != NULL) { 423 substring_t args[MAX_OPT_ARGS]; 424 int token; 425 unsigned long lnum; 426 427 if (result < 0) 428 break; 429 if ((*p == '\0') || (*p == ' ') || (*p == '\t')) 430 continue; 431 token = match_token(p, policy_tokens, args); 432 switch (token) { 433 case Opt_measure: 434 ima_log_string(ab, "action", "measure"); 435 436 if (entry->action != UNKNOWN) 437 result = -EINVAL; 438 439 entry->action = MEASURE; 440 break; 441 case Opt_dont_measure: 442 ima_log_string(ab, "action", "dont_measure"); 443 444 if (entry->action != UNKNOWN) 445 result = -EINVAL; 446 447 entry->action = DONT_MEASURE; 448 break; 449 case Opt_appraise: 450 ima_log_string(ab, "action", "appraise"); 451 452 if (entry->action != UNKNOWN) 453 result = -EINVAL; 454 455 entry->action = APPRAISE; 456 break; 457 case Opt_dont_appraise: 458 ima_log_string(ab, "action", "dont_appraise"); 459 460 if (entry->action != UNKNOWN) 461 result = -EINVAL; 462 463 entry->action = DONT_APPRAISE; 464 break; 465 case Opt_audit: 466 ima_log_string(ab, "action", "audit"); 467 468 if (entry->action != UNKNOWN) 469 result = -EINVAL; 470 471 entry->action = AUDIT; 472 break; 473 case Opt_func: 474 ima_log_string(ab, "func", args[0].from); 475 476 if (entry->func) 477 result = -EINVAL; 478 479 if (strcmp(args[0].from, "FILE_CHECK") == 0) 480 entry->func = FILE_CHECK; 481 /* PATH_CHECK is for backwards compat */ 482 else if (strcmp(args[0].from, "PATH_CHECK") == 0) 483 entry->func = FILE_CHECK; 484 else if (strcmp(args[0].from, "MODULE_CHECK") == 0) 485 entry->func = MODULE_CHECK; 486 else if ((strcmp(args[0].from, "FILE_MMAP") == 0) 487 || (strcmp(args[0].from, "MMAP_CHECK") == 0)) 488 entry->func = MMAP_CHECK; 489 else if (strcmp(args[0].from, "BPRM_CHECK") == 0) 490 entry->func = BPRM_CHECK; 491 else 492 result = -EINVAL; 493 if (!result) 494 entry->flags |= IMA_FUNC; 495 break; 496 case Opt_mask: 497 ima_log_string(ab, "mask", args[0].from); 498 499 if (entry->mask) 500 result = -EINVAL; 501 502 if ((strcmp(args[0].from, "MAY_EXEC")) == 0) 503 entry->mask = MAY_EXEC; 504 else if (strcmp(args[0].from, "MAY_WRITE") == 0) 505 entry->mask = MAY_WRITE; 506 else if (strcmp(args[0].from, "MAY_READ") == 0) 507 entry->mask = MAY_READ; 508 else if (strcmp(args[0].from, "MAY_APPEND") == 0) 509 entry->mask = MAY_APPEND; 510 else 511 result = -EINVAL; 512 if (!result) 513 entry->flags |= IMA_MASK; 514 break; 515 case Opt_fsmagic: 516 ima_log_string(ab, "fsmagic", args[0].from); 517 518 if (entry->fsmagic) { 519 result = -EINVAL; 520 break; 521 } 522 523 result = strict_strtoul(args[0].from, 16, 524 &entry->fsmagic); 525 if (!result) 526 entry->flags |= IMA_FSMAGIC; 527 break; 528 case Opt_fsuuid: 529 ima_log_string(ab, "fsuuid", args[0].from); 530 531 if (memchr_inv(entry->fsuuid, 0x00, 532 sizeof(entry->fsuuid))) { 533 result = -EINVAL; 534 break; 535 } 536 537 result = blk_part_pack_uuid(args[0].from, 538 entry->fsuuid); 539 if (!result) 540 entry->flags |= IMA_FSUUID; 541 break; 542 case Opt_uid: 543 ima_log_string(ab, "uid", args[0].from); 544 545 if (uid_valid(entry->uid)) { 546 result = -EINVAL; 547 break; 548 } 549 550 result = strict_strtoul(args[0].from, 10, &lnum); 551 if (!result) { 552 entry->uid = make_kuid(current_user_ns(), (uid_t)lnum); 553 if (!uid_valid(entry->uid) || (((uid_t)lnum) != lnum)) 554 result = -EINVAL; 555 else 556 entry->flags |= IMA_UID; 557 } 558 break; 559 case Opt_fowner: 560 ima_log_string(ab, "fowner", args[0].from); 561 562 if (uid_valid(entry->fowner)) { 563 result = -EINVAL; 564 break; 565 } 566 567 result = strict_strtoul(args[0].from, 10, &lnum); 568 if (!result) { 569 entry->fowner = make_kuid(current_user_ns(), (uid_t)lnum); 570 if (!uid_valid(entry->fowner) || (((uid_t)lnum) != lnum)) 571 result = -EINVAL; 572 else 573 entry->flags |= IMA_FOWNER; 574 } 575 break; 576 case Opt_obj_user: 577 ima_log_string(ab, "obj_user", args[0].from); 578 result = ima_lsm_rule_init(entry, args, 579 LSM_OBJ_USER, 580 AUDIT_OBJ_USER); 581 break; 582 case Opt_obj_role: 583 ima_log_string(ab, "obj_role", args[0].from); 584 result = ima_lsm_rule_init(entry, args, 585 LSM_OBJ_ROLE, 586 AUDIT_OBJ_ROLE); 587 break; 588 case Opt_obj_type: 589 ima_log_string(ab, "obj_type", args[0].from); 590 result = ima_lsm_rule_init(entry, args, 591 LSM_OBJ_TYPE, 592 AUDIT_OBJ_TYPE); 593 break; 594 case Opt_subj_user: 595 ima_log_string(ab, "subj_user", args[0].from); 596 result = ima_lsm_rule_init(entry, args, 597 LSM_SUBJ_USER, 598 AUDIT_SUBJ_USER); 599 break; 600 case Opt_subj_role: 601 ima_log_string(ab, "subj_role", args[0].from); 602 result = ima_lsm_rule_init(entry, args, 603 LSM_SUBJ_ROLE, 604 AUDIT_SUBJ_ROLE); 605 break; 606 case Opt_subj_type: 607 ima_log_string(ab, "subj_type", args[0].from); 608 result = ima_lsm_rule_init(entry, args, 609 LSM_SUBJ_TYPE, 610 AUDIT_SUBJ_TYPE); 611 break; 612 case Opt_appraise_type: 613 if (entry->action != APPRAISE) { 614 result = -EINVAL; 615 break; 616 } 617 618 ima_log_string(ab, "appraise_type", args[0].from); 619 if ((strcmp(args[0].from, "imasig")) == 0) 620 entry->flags |= IMA_DIGSIG_REQUIRED; 621 else 622 result = -EINVAL; 623 break; 624 case Opt_err: 625 ima_log_string(ab, "UNKNOWN", p); 626 result = -EINVAL; 627 break; 628 } 629 } 630 if (!result && (entry->action == UNKNOWN)) 631 result = -EINVAL; 632 else if (entry->func == MODULE_CHECK) 633 ima_appraise |= IMA_APPRAISE_MODULES; 634 audit_log_format(ab, "res=%d", !result); 635 audit_log_end(ab); 636 return result; 637 } 638 639 /** 640 * ima_parse_add_rule - add a rule to ima_policy_rules 641 * @rule - ima measurement policy rule 642 * 643 * Uses a mutex to protect the policy list from multiple concurrent writers. 644 * Returns the length of the rule parsed, an error code on failure 645 */ 646 ssize_t ima_parse_add_rule(char *rule) 647 { 648 const char *op = "update_policy"; 649 char *p; 650 struct ima_rule_entry *entry; 651 ssize_t result, len; 652 int audit_info = 0; 653 654 /* Prevent installed policy from changing */ 655 if (ima_rules != &ima_default_rules) { 656 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, 657 NULL, op, "already exists", 658 -EACCES, audit_info); 659 return -EACCES; 660 } 661 662 entry = kzalloc(sizeof(*entry), GFP_KERNEL); 663 if (!entry) { 664 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, 665 NULL, op, "-ENOMEM", -ENOMEM, audit_info); 666 return -ENOMEM; 667 } 668 669 INIT_LIST_HEAD(&entry->list); 670 671 p = strsep(&rule, "\n"); 672 len = strlen(p) + 1; 673 674 if (*p == '#') { 675 kfree(entry); 676 return len; 677 } 678 679 result = ima_parse_rule(p, entry); 680 if (result) { 681 kfree(entry); 682 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, 683 NULL, op, "invalid policy", result, 684 audit_info); 685 return result; 686 } 687 688 mutex_lock(&ima_rules_mutex); 689 list_add_tail(&entry->list, &ima_policy_rules); 690 mutex_unlock(&ima_rules_mutex); 691 692 return len; 693 } 694 695 /* ima_delete_rules called to cleanup invalid policy */ 696 void ima_delete_rules(void) 697 { 698 struct ima_rule_entry *entry, *tmp; 699 int i; 700 701 mutex_lock(&ima_rules_mutex); 702 list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) { 703 for (i = 0; i < MAX_LSM_RULES; i++) 704 kfree(entry->lsm[i].args_p); 705 706 list_del(&entry->list); 707 kfree(entry); 708 } 709 mutex_unlock(&ima_rules_mutex); 710 } 711