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, Opt_permit_directio 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_permit_directio, "permit_directio"}, 379 {Opt_err, NULL} 380 }; 381 382 static int ima_lsm_rule_init(struct ima_rule_entry *entry, 383 substring_t *args, int lsm_rule, int audit_type) 384 { 385 int result; 386 387 if (entry->lsm[lsm_rule].rule) 388 return -EINVAL; 389 390 entry->lsm[lsm_rule].args_p = match_strdup(args); 391 if (!entry->lsm[lsm_rule].args_p) 392 return -ENOMEM; 393 394 entry->lsm[lsm_rule].type = audit_type; 395 result = security_filter_rule_init(entry->lsm[lsm_rule].type, 396 Audit_equal, 397 entry->lsm[lsm_rule].args_p, 398 &entry->lsm[lsm_rule].rule); 399 if (!entry->lsm[lsm_rule].rule) { 400 kfree(entry->lsm[lsm_rule].args_p); 401 return -EINVAL; 402 } 403 404 return result; 405 } 406 407 static void ima_log_string(struct audit_buffer *ab, char *key, char *value) 408 { 409 audit_log_format(ab, "%s=", key); 410 audit_log_untrustedstring(ab, value); 411 audit_log_format(ab, " "); 412 } 413 414 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) 415 { 416 struct audit_buffer *ab; 417 char *p; 418 int result = 0; 419 420 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE); 421 422 entry->uid = INVALID_UID; 423 entry->fowner = INVALID_UID; 424 entry->action = UNKNOWN; 425 while ((p = strsep(&rule, " \t")) != NULL) { 426 substring_t args[MAX_OPT_ARGS]; 427 int token; 428 unsigned long lnum; 429 430 if (result < 0) 431 break; 432 if ((*p == '\0') || (*p == ' ') || (*p == '\t')) 433 continue; 434 token = match_token(p, policy_tokens, args); 435 switch (token) { 436 case Opt_measure: 437 ima_log_string(ab, "action", "measure"); 438 439 if (entry->action != UNKNOWN) 440 result = -EINVAL; 441 442 entry->action = MEASURE; 443 break; 444 case Opt_dont_measure: 445 ima_log_string(ab, "action", "dont_measure"); 446 447 if (entry->action != UNKNOWN) 448 result = -EINVAL; 449 450 entry->action = DONT_MEASURE; 451 break; 452 case Opt_appraise: 453 ima_log_string(ab, "action", "appraise"); 454 455 if (entry->action != UNKNOWN) 456 result = -EINVAL; 457 458 entry->action = APPRAISE; 459 break; 460 case Opt_dont_appraise: 461 ima_log_string(ab, "action", "dont_appraise"); 462 463 if (entry->action != UNKNOWN) 464 result = -EINVAL; 465 466 entry->action = DONT_APPRAISE; 467 break; 468 case Opt_audit: 469 ima_log_string(ab, "action", "audit"); 470 471 if (entry->action != UNKNOWN) 472 result = -EINVAL; 473 474 entry->action = AUDIT; 475 break; 476 case Opt_func: 477 ima_log_string(ab, "func", args[0].from); 478 479 if (entry->func) 480 result = -EINVAL; 481 482 if (strcmp(args[0].from, "FILE_CHECK") == 0) 483 entry->func = FILE_CHECK; 484 /* PATH_CHECK is for backwards compat */ 485 else if (strcmp(args[0].from, "PATH_CHECK") == 0) 486 entry->func = FILE_CHECK; 487 else if (strcmp(args[0].from, "MODULE_CHECK") == 0) 488 entry->func = MODULE_CHECK; 489 else if ((strcmp(args[0].from, "FILE_MMAP") == 0) 490 || (strcmp(args[0].from, "MMAP_CHECK") == 0)) 491 entry->func = MMAP_CHECK; 492 else if (strcmp(args[0].from, "BPRM_CHECK") == 0) 493 entry->func = BPRM_CHECK; 494 else 495 result = -EINVAL; 496 if (!result) 497 entry->flags |= IMA_FUNC; 498 break; 499 case Opt_mask: 500 ima_log_string(ab, "mask", args[0].from); 501 502 if (entry->mask) 503 result = -EINVAL; 504 505 if ((strcmp(args[0].from, "MAY_EXEC")) == 0) 506 entry->mask = MAY_EXEC; 507 else if (strcmp(args[0].from, "MAY_WRITE") == 0) 508 entry->mask = MAY_WRITE; 509 else if (strcmp(args[0].from, "MAY_READ") == 0) 510 entry->mask = MAY_READ; 511 else if (strcmp(args[0].from, "MAY_APPEND") == 0) 512 entry->mask = MAY_APPEND; 513 else 514 result = -EINVAL; 515 if (!result) 516 entry->flags |= IMA_MASK; 517 break; 518 case Opt_fsmagic: 519 ima_log_string(ab, "fsmagic", args[0].from); 520 521 if (entry->fsmagic) { 522 result = -EINVAL; 523 break; 524 } 525 526 result = kstrtoul(args[0].from, 16, &entry->fsmagic); 527 if (!result) 528 entry->flags |= IMA_FSMAGIC; 529 break; 530 case Opt_fsuuid: 531 ima_log_string(ab, "fsuuid", args[0].from); 532 533 if (memchr_inv(entry->fsuuid, 0x00, 534 sizeof(entry->fsuuid))) { 535 result = -EINVAL; 536 break; 537 } 538 539 result = blk_part_pack_uuid(args[0].from, 540 entry->fsuuid); 541 if (!result) 542 entry->flags |= IMA_FSUUID; 543 break; 544 case Opt_uid: 545 ima_log_string(ab, "uid", args[0].from); 546 547 if (uid_valid(entry->uid)) { 548 result = -EINVAL; 549 break; 550 } 551 552 result = kstrtoul(args[0].from, 10, &lnum); 553 if (!result) { 554 entry->uid = make_kuid(current_user_ns(), (uid_t)lnum); 555 if (!uid_valid(entry->uid) || (((uid_t)lnum) != lnum)) 556 result = -EINVAL; 557 else 558 entry->flags |= IMA_UID; 559 } 560 break; 561 case Opt_fowner: 562 ima_log_string(ab, "fowner", args[0].from); 563 564 if (uid_valid(entry->fowner)) { 565 result = -EINVAL; 566 break; 567 } 568 569 result = kstrtoul(args[0].from, 10, &lnum); 570 if (!result) { 571 entry->fowner = make_kuid(current_user_ns(), (uid_t)lnum); 572 if (!uid_valid(entry->fowner) || (((uid_t)lnum) != lnum)) 573 result = -EINVAL; 574 else 575 entry->flags |= IMA_FOWNER; 576 } 577 break; 578 case Opt_obj_user: 579 ima_log_string(ab, "obj_user", args[0].from); 580 result = ima_lsm_rule_init(entry, args, 581 LSM_OBJ_USER, 582 AUDIT_OBJ_USER); 583 break; 584 case Opt_obj_role: 585 ima_log_string(ab, "obj_role", args[0].from); 586 result = ima_lsm_rule_init(entry, args, 587 LSM_OBJ_ROLE, 588 AUDIT_OBJ_ROLE); 589 break; 590 case Opt_obj_type: 591 ima_log_string(ab, "obj_type", args[0].from); 592 result = ima_lsm_rule_init(entry, args, 593 LSM_OBJ_TYPE, 594 AUDIT_OBJ_TYPE); 595 break; 596 case Opt_subj_user: 597 ima_log_string(ab, "subj_user", args[0].from); 598 result = ima_lsm_rule_init(entry, args, 599 LSM_SUBJ_USER, 600 AUDIT_SUBJ_USER); 601 break; 602 case Opt_subj_role: 603 ima_log_string(ab, "subj_role", args[0].from); 604 result = ima_lsm_rule_init(entry, args, 605 LSM_SUBJ_ROLE, 606 AUDIT_SUBJ_ROLE); 607 break; 608 case Opt_subj_type: 609 ima_log_string(ab, "subj_type", args[0].from); 610 result = ima_lsm_rule_init(entry, args, 611 LSM_SUBJ_TYPE, 612 AUDIT_SUBJ_TYPE); 613 break; 614 case Opt_appraise_type: 615 if (entry->action != APPRAISE) { 616 result = -EINVAL; 617 break; 618 } 619 620 ima_log_string(ab, "appraise_type", args[0].from); 621 if ((strcmp(args[0].from, "imasig")) == 0) 622 entry->flags |= IMA_DIGSIG_REQUIRED; 623 else 624 result = -EINVAL; 625 break; 626 case Opt_permit_directio: 627 entry->flags |= IMA_PERMIT_DIRECTIO; 628 break; 629 case Opt_err: 630 ima_log_string(ab, "UNKNOWN", p); 631 result = -EINVAL; 632 break; 633 } 634 } 635 if (!result && (entry->action == UNKNOWN)) 636 result = -EINVAL; 637 else if (entry->func == MODULE_CHECK) 638 ima_appraise |= IMA_APPRAISE_MODULES; 639 audit_log_format(ab, "res=%d", !result); 640 audit_log_end(ab); 641 return result; 642 } 643 644 /** 645 * ima_parse_add_rule - add a rule to ima_policy_rules 646 * @rule - ima measurement policy rule 647 * 648 * Uses a mutex to protect the policy list from multiple concurrent writers. 649 * Returns the length of the rule parsed, an error code on failure 650 */ 651 ssize_t ima_parse_add_rule(char *rule) 652 { 653 static const char op[] = "update_policy"; 654 char *p; 655 struct ima_rule_entry *entry; 656 ssize_t result, len; 657 int audit_info = 0; 658 659 /* Prevent installed policy from changing */ 660 if (ima_rules != &ima_default_rules) { 661 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, 662 NULL, op, "already exists", 663 -EACCES, audit_info); 664 return -EACCES; 665 } 666 667 entry = kzalloc(sizeof(*entry), GFP_KERNEL); 668 if (!entry) { 669 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, 670 NULL, op, "-ENOMEM", -ENOMEM, audit_info); 671 return -ENOMEM; 672 } 673 674 INIT_LIST_HEAD(&entry->list); 675 676 p = strsep(&rule, "\n"); 677 len = strlen(p) + 1; 678 679 if (*p == '#') { 680 kfree(entry); 681 return len; 682 } 683 684 result = ima_parse_rule(p, entry); 685 if (result) { 686 kfree(entry); 687 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, 688 NULL, op, "invalid policy", result, 689 audit_info); 690 return result; 691 } 692 693 mutex_lock(&ima_rules_mutex); 694 list_add_tail(&entry->list, &ima_policy_rules); 695 mutex_unlock(&ima_rules_mutex); 696 697 return len; 698 } 699 700 /* ima_delete_rules called to cleanup invalid policy */ 701 void ima_delete_rules(void) 702 { 703 struct ima_rule_entry *entry, *tmp; 704 int i; 705 706 mutex_lock(&ima_rules_mutex); 707 list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) { 708 for (i = 0; i < MAX_LSM_RULES; i++) 709 kfree(entry->lsm[i].args_p); 710 711 list_del(&entry->list); 712 kfree(entry); 713 } 714 mutex_unlock(&ima_rules_mutex); 715 } 716