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) && 171 (rule->func != func && func != POST_SETATTR)) 172 return false; 173 if ((rule->flags & IMA_MASK) && 174 (rule->mask != mask && func != POST_SETATTR)) 175 return false; 176 if ((rule->flags & IMA_FSMAGIC) 177 && rule->fsmagic != inode->i_sb->s_magic) 178 return false; 179 if ((rule->flags & IMA_FSUUID) && 180 memcmp(rule->fsuuid, inode->i_sb->s_uuid, sizeof(rule->fsuuid))) 181 return false; 182 if ((rule->flags & IMA_UID) && !uid_eq(rule->uid, cred->uid)) 183 return false; 184 if ((rule->flags & IMA_FOWNER) && !uid_eq(rule->fowner, inode->i_uid)) 185 return false; 186 for (i = 0; i < MAX_LSM_RULES; i++) { 187 int rc = 0; 188 u32 osid, sid; 189 int retried = 0; 190 191 if (!rule->lsm[i].rule) 192 continue; 193 retry: 194 switch (i) { 195 case LSM_OBJ_USER: 196 case LSM_OBJ_ROLE: 197 case LSM_OBJ_TYPE: 198 security_inode_getsecid(inode, &osid); 199 rc = security_filter_rule_match(osid, 200 rule->lsm[i].type, 201 Audit_equal, 202 rule->lsm[i].rule, 203 NULL); 204 break; 205 case LSM_SUBJ_USER: 206 case LSM_SUBJ_ROLE: 207 case LSM_SUBJ_TYPE: 208 security_task_getsecid(tsk, &sid); 209 rc = security_filter_rule_match(sid, 210 rule->lsm[i].type, 211 Audit_equal, 212 rule->lsm[i].rule, 213 NULL); 214 default: 215 break; 216 } 217 if ((rc < 0) && (!retried)) { 218 retried = 1; 219 ima_lsm_update_rules(); 220 goto retry; 221 } 222 if (!rc) 223 return false; 224 } 225 return true; 226 } 227 228 /* 229 * In addition to knowing that we need to appraise the file in general, 230 * we need to differentiate between calling hooks, for hook specific rules. 231 */ 232 static int get_subaction(struct ima_rule_entry *rule, int func) 233 { 234 if (!(rule->flags & IMA_FUNC)) 235 return IMA_FILE_APPRAISE; 236 237 switch (func) { 238 case MMAP_CHECK: 239 return IMA_MMAP_APPRAISE; 240 case BPRM_CHECK: 241 return IMA_BPRM_APPRAISE; 242 case MODULE_CHECK: 243 return IMA_MODULE_APPRAISE; 244 case FILE_CHECK: 245 default: 246 return IMA_FILE_APPRAISE; 247 } 248 } 249 250 /** 251 * ima_match_policy - decision based on LSM and other conditions 252 * @inode: pointer to an inode for which the policy decision is being made 253 * @func: IMA hook identifier 254 * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC) 255 * 256 * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type) 257 * conditions. 258 * 259 * (There is no need for locking when walking the policy list, 260 * as elements in the list are never deleted, nor does the list 261 * change.) 262 */ 263 int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask, 264 int flags) 265 { 266 struct ima_rule_entry *entry; 267 int action = 0, actmask = flags | (flags << 1); 268 269 list_for_each_entry(entry, ima_rules, list) { 270 271 if (!(entry->action & actmask)) 272 continue; 273 274 if (!ima_match_rules(entry, inode, func, mask)) 275 continue; 276 277 action |= entry->flags & IMA_ACTION_FLAGS; 278 279 action |= entry->action & IMA_DO_MASK; 280 if (entry->action & IMA_APPRAISE) 281 action |= get_subaction(entry, func); 282 283 if (entry->action & IMA_DO_MASK) 284 actmask &= ~(entry->action | entry->action << 1); 285 else 286 actmask &= ~(entry->action | entry->action >> 1); 287 288 if (!actmask) 289 break; 290 } 291 292 return action; 293 } 294 295 /** 296 * ima_init_policy - initialize the default measure rules. 297 * 298 * ima_rules points to either the ima_default_rules or the 299 * the new ima_policy_rules. 300 */ 301 void __init ima_init_policy(void) 302 { 303 int i, measure_entries, appraise_entries; 304 305 /* if !ima_use_tcb set entries = 0 so we load NO default rules */ 306 measure_entries = ima_use_tcb ? ARRAY_SIZE(default_rules) : 0; 307 appraise_entries = ima_use_appraise_tcb ? 308 ARRAY_SIZE(default_appraise_rules) : 0; 309 310 for (i = 0; i < measure_entries + appraise_entries; i++) { 311 if (i < measure_entries) 312 list_add_tail(&default_rules[i].list, 313 &ima_default_rules); 314 else { 315 int j = i - measure_entries; 316 317 list_add_tail(&default_appraise_rules[j].list, 318 &ima_default_rules); 319 } 320 } 321 322 ima_rules = &ima_default_rules; 323 } 324 325 /** 326 * ima_update_policy - update default_rules with new measure rules 327 * 328 * Called on file .release to update the default rules with a complete new 329 * policy. Once updated, the policy is locked, no additional rules can be 330 * added to the policy. 331 */ 332 void ima_update_policy(void) 333 { 334 static const char op[] = "policy_update"; 335 const char *cause = "already exists"; 336 int result = 1; 337 int audit_info = 0; 338 339 if (ima_rules == &ima_default_rules) { 340 ima_rules = &ima_policy_rules; 341 cause = "complete"; 342 result = 0; 343 } 344 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, 345 NULL, op, cause, result, audit_info); 346 } 347 348 enum { 349 Opt_err = -1, 350 Opt_measure = 1, Opt_dont_measure, 351 Opt_appraise, Opt_dont_appraise, 352 Opt_audit, 353 Opt_obj_user, Opt_obj_role, Opt_obj_type, 354 Opt_subj_user, Opt_subj_role, Opt_subj_type, 355 Opt_func, Opt_mask, Opt_fsmagic, Opt_uid, Opt_fowner, 356 Opt_appraise_type, Opt_fsuuid 357 }; 358 359 static match_table_t policy_tokens = { 360 {Opt_measure, "measure"}, 361 {Opt_dont_measure, "dont_measure"}, 362 {Opt_appraise, "appraise"}, 363 {Opt_dont_appraise, "dont_appraise"}, 364 {Opt_audit, "audit"}, 365 {Opt_obj_user, "obj_user=%s"}, 366 {Opt_obj_role, "obj_role=%s"}, 367 {Opt_obj_type, "obj_type=%s"}, 368 {Opt_subj_user, "subj_user=%s"}, 369 {Opt_subj_role, "subj_role=%s"}, 370 {Opt_subj_type, "subj_type=%s"}, 371 {Opt_func, "func=%s"}, 372 {Opt_mask, "mask=%s"}, 373 {Opt_fsmagic, "fsmagic=%s"}, 374 {Opt_fsuuid, "fsuuid=%s"}, 375 {Opt_uid, "uid=%s"}, 376 {Opt_fowner, "fowner=%s"}, 377 {Opt_appraise_type, "appraise_type=%s"}, 378 {Opt_err, NULL} 379 }; 380 381 static int ima_lsm_rule_init(struct ima_rule_entry *entry, 382 substring_t *args, int lsm_rule, int audit_type) 383 { 384 int result; 385 386 if (entry->lsm[lsm_rule].rule) 387 return -EINVAL; 388 389 entry->lsm[lsm_rule].args_p = match_strdup(args); 390 if (!entry->lsm[lsm_rule].args_p) 391 return -ENOMEM; 392 393 entry->lsm[lsm_rule].type = audit_type; 394 result = security_filter_rule_init(entry->lsm[lsm_rule].type, 395 Audit_equal, 396 entry->lsm[lsm_rule].args_p, 397 &entry->lsm[lsm_rule].rule); 398 if (!entry->lsm[lsm_rule].rule) { 399 kfree(entry->lsm[lsm_rule].args_p); 400 return -EINVAL; 401 } 402 403 return result; 404 } 405 406 static void ima_log_string(struct audit_buffer *ab, char *key, char *value) 407 { 408 audit_log_format(ab, "%s=", key); 409 audit_log_untrustedstring(ab, value); 410 audit_log_format(ab, " "); 411 } 412 413 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) 414 { 415 struct audit_buffer *ab; 416 char *p; 417 int result = 0; 418 419 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE); 420 421 entry->uid = INVALID_UID; 422 entry->fowner = INVALID_UID; 423 entry->action = UNKNOWN; 424 while ((p = strsep(&rule, " \t")) != NULL) { 425 substring_t args[MAX_OPT_ARGS]; 426 int token; 427 unsigned long lnum; 428 429 if (result < 0) 430 break; 431 if ((*p == '\0') || (*p == ' ') || (*p == '\t')) 432 continue; 433 token = match_token(p, policy_tokens, args); 434 switch (token) { 435 case Opt_measure: 436 ima_log_string(ab, "action", "measure"); 437 438 if (entry->action != UNKNOWN) 439 result = -EINVAL; 440 441 entry->action = MEASURE; 442 break; 443 case Opt_dont_measure: 444 ima_log_string(ab, "action", "dont_measure"); 445 446 if (entry->action != UNKNOWN) 447 result = -EINVAL; 448 449 entry->action = DONT_MEASURE; 450 break; 451 case Opt_appraise: 452 ima_log_string(ab, "action", "appraise"); 453 454 if (entry->action != UNKNOWN) 455 result = -EINVAL; 456 457 entry->action = APPRAISE; 458 break; 459 case Opt_dont_appraise: 460 ima_log_string(ab, "action", "dont_appraise"); 461 462 if (entry->action != UNKNOWN) 463 result = -EINVAL; 464 465 entry->action = DONT_APPRAISE; 466 break; 467 case Opt_audit: 468 ima_log_string(ab, "action", "audit"); 469 470 if (entry->action != UNKNOWN) 471 result = -EINVAL; 472 473 entry->action = AUDIT; 474 break; 475 case Opt_func: 476 ima_log_string(ab, "func", args[0].from); 477 478 if (entry->func) 479 result = -EINVAL; 480 481 if (strcmp(args[0].from, "FILE_CHECK") == 0) 482 entry->func = FILE_CHECK; 483 /* PATH_CHECK is for backwards compat */ 484 else if (strcmp(args[0].from, "PATH_CHECK") == 0) 485 entry->func = FILE_CHECK; 486 else if (strcmp(args[0].from, "MODULE_CHECK") == 0) 487 entry->func = MODULE_CHECK; 488 else if ((strcmp(args[0].from, "FILE_MMAP") == 0) 489 || (strcmp(args[0].from, "MMAP_CHECK") == 0)) 490 entry->func = MMAP_CHECK; 491 else if (strcmp(args[0].from, "BPRM_CHECK") == 0) 492 entry->func = BPRM_CHECK; 493 else 494 result = -EINVAL; 495 if (!result) 496 entry->flags |= IMA_FUNC; 497 break; 498 case Opt_mask: 499 ima_log_string(ab, "mask", args[0].from); 500 501 if (entry->mask) 502 result = -EINVAL; 503 504 if ((strcmp(args[0].from, "MAY_EXEC")) == 0) 505 entry->mask = MAY_EXEC; 506 else if (strcmp(args[0].from, "MAY_WRITE") == 0) 507 entry->mask = MAY_WRITE; 508 else if (strcmp(args[0].from, "MAY_READ") == 0) 509 entry->mask = MAY_READ; 510 else if (strcmp(args[0].from, "MAY_APPEND") == 0) 511 entry->mask = MAY_APPEND; 512 else 513 result = -EINVAL; 514 if (!result) 515 entry->flags |= IMA_MASK; 516 break; 517 case Opt_fsmagic: 518 ima_log_string(ab, "fsmagic", args[0].from); 519 520 if (entry->fsmagic) { 521 result = -EINVAL; 522 break; 523 } 524 525 result = kstrtoul(args[0].from, 16, &entry->fsmagic); 526 if (!result) 527 entry->flags |= IMA_FSMAGIC; 528 break; 529 case Opt_fsuuid: 530 ima_log_string(ab, "fsuuid", args[0].from); 531 532 if (memchr_inv(entry->fsuuid, 0x00, 533 sizeof(entry->fsuuid))) { 534 result = -EINVAL; 535 break; 536 } 537 538 result = blk_part_pack_uuid(args[0].from, 539 entry->fsuuid); 540 if (!result) 541 entry->flags |= IMA_FSUUID; 542 break; 543 case Opt_uid: 544 ima_log_string(ab, "uid", args[0].from); 545 546 if (uid_valid(entry->uid)) { 547 result = -EINVAL; 548 break; 549 } 550 551 result = kstrtoul(args[0].from, 10, &lnum); 552 if (!result) { 553 entry->uid = make_kuid(current_user_ns(), (uid_t)lnum); 554 if (!uid_valid(entry->uid) || (((uid_t)lnum) != lnum)) 555 result = -EINVAL; 556 else 557 entry->flags |= IMA_UID; 558 } 559 break; 560 case Opt_fowner: 561 ima_log_string(ab, "fowner", args[0].from); 562 563 if (uid_valid(entry->fowner)) { 564 result = -EINVAL; 565 break; 566 } 567 568 result = kstrtoul(args[0].from, 10, &lnum); 569 if (!result) { 570 entry->fowner = make_kuid(current_user_ns(), (uid_t)lnum); 571 if (!uid_valid(entry->fowner) || (((uid_t)lnum) != lnum)) 572 result = -EINVAL; 573 else 574 entry->flags |= IMA_FOWNER; 575 } 576 break; 577 case Opt_obj_user: 578 ima_log_string(ab, "obj_user", args[0].from); 579 result = ima_lsm_rule_init(entry, args, 580 LSM_OBJ_USER, 581 AUDIT_OBJ_USER); 582 break; 583 case Opt_obj_role: 584 ima_log_string(ab, "obj_role", args[0].from); 585 result = ima_lsm_rule_init(entry, args, 586 LSM_OBJ_ROLE, 587 AUDIT_OBJ_ROLE); 588 break; 589 case Opt_obj_type: 590 ima_log_string(ab, "obj_type", args[0].from); 591 result = ima_lsm_rule_init(entry, args, 592 LSM_OBJ_TYPE, 593 AUDIT_OBJ_TYPE); 594 break; 595 case Opt_subj_user: 596 ima_log_string(ab, "subj_user", args[0].from); 597 result = ima_lsm_rule_init(entry, args, 598 LSM_SUBJ_USER, 599 AUDIT_SUBJ_USER); 600 break; 601 case Opt_subj_role: 602 ima_log_string(ab, "subj_role", args[0].from); 603 result = ima_lsm_rule_init(entry, args, 604 LSM_SUBJ_ROLE, 605 AUDIT_SUBJ_ROLE); 606 break; 607 case Opt_subj_type: 608 ima_log_string(ab, "subj_type", args[0].from); 609 result = ima_lsm_rule_init(entry, args, 610 LSM_SUBJ_TYPE, 611 AUDIT_SUBJ_TYPE); 612 break; 613 case Opt_appraise_type: 614 if (entry->action != APPRAISE) { 615 result = -EINVAL; 616 break; 617 } 618 619 ima_log_string(ab, "appraise_type", args[0].from); 620 if ((strcmp(args[0].from, "imasig")) == 0) 621 entry->flags |= IMA_DIGSIG_REQUIRED; 622 else 623 result = -EINVAL; 624 break; 625 case Opt_err: 626 ima_log_string(ab, "UNKNOWN", p); 627 result = -EINVAL; 628 break; 629 } 630 } 631 if (!result && (entry->action == UNKNOWN)) 632 result = -EINVAL; 633 else if (entry->func == MODULE_CHECK) 634 ima_appraise |= IMA_APPRAISE_MODULES; 635 audit_log_format(ab, "res=%d", !result); 636 audit_log_end(ab); 637 return result; 638 } 639 640 /** 641 * ima_parse_add_rule - add a rule to ima_policy_rules 642 * @rule - ima measurement policy rule 643 * 644 * Uses a mutex to protect the policy list from multiple concurrent writers. 645 * Returns the length of the rule parsed, an error code on failure 646 */ 647 ssize_t ima_parse_add_rule(char *rule) 648 { 649 static const char op[] = "update_policy"; 650 char *p; 651 struct ima_rule_entry *entry; 652 ssize_t result, len; 653 int audit_info = 0; 654 655 /* Prevent installed policy from changing */ 656 if (ima_rules != &ima_default_rules) { 657 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, 658 NULL, op, "already exists", 659 -EACCES, audit_info); 660 return -EACCES; 661 } 662 663 entry = kzalloc(sizeof(*entry), GFP_KERNEL); 664 if (!entry) { 665 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, 666 NULL, op, "-ENOMEM", -ENOMEM, audit_info); 667 return -ENOMEM; 668 } 669 670 INIT_LIST_HEAD(&entry->list); 671 672 p = strsep(&rule, "\n"); 673 len = strlen(p) + 1; 674 675 if (*p == '#') { 676 kfree(entry); 677 return len; 678 } 679 680 result = ima_parse_rule(p, entry); 681 if (result) { 682 kfree(entry); 683 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, 684 NULL, op, "invalid policy", result, 685 audit_info); 686 return result; 687 } 688 689 mutex_lock(&ima_rules_mutex); 690 list_add_tail(&entry->list, &ima_policy_rules); 691 mutex_unlock(&ima_rules_mutex); 692 693 return len; 694 } 695 696 /* ima_delete_rules called to cleanup invalid policy */ 697 void ima_delete_rules(void) 698 { 699 struct ima_rule_entry *entry, *tmp; 700 int i; 701 702 mutex_lock(&ima_rules_mutex); 703 list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) { 704 for (i = 0; i < MAX_LSM_RULES; i++) 705 kfree(entry->lsm[i].args_p); 706 707 list_del(&entry->list); 708 kfree(entry); 709 } 710 mutex_unlock(&ima_rules_mutex); 711 } 712