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 {.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC}, 88 }; 89 90 static struct ima_rule_entry default_appraise_rules[] = { 91 {.action = DONT_APPRAISE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC}, 92 {.action = DONT_APPRAISE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC}, 93 {.action = DONT_APPRAISE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC}, 94 {.action = DONT_APPRAISE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC}, 95 {.action = DONT_APPRAISE, .fsmagic = RAMFS_MAGIC, .flags = IMA_FSMAGIC}, 96 {.action = DONT_APPRAISE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC}, 97 {.action = DONT_APPRAISE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC}, 98 {.action = DONT_APPRAISE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC}, 99 {.action = DONT_APPRAISE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC}, 100 {.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC}, 101 {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .flags = IMA_FOWNER}, 102 }; 103 104 static LIST_HEAD(ima_default_rules); 105 static LIST_HEAD(ima_policy_rules); 106 static struct list_head *ima_rules; 107 108 static DEFINE_MUTEX(ima_rules_mutex); 109 110 static bool ima_use_tcb __initdata; 111 static int __init default_measure_policy_setup(char *str) 112 { 113 ima_use_tcb = 1; 114 return 1; 115 } 116 __setup("ima_tcb", default_measure_policy_setup); 117 118 static bool ima_use_appraise_tcb __initdata; 119 static int __init default_appraise_policy_setup(char *str) 120 { 121 ima_use_appraise_tcb = 1; 122 return 1; 123 } 124 __setup("ima_appraise_tcb", default_appraise_policy_setup); 125 126 /* 127 * Although the IMA policy does not change, the LSM policy can be 128 * reloaded, leaving the IMA LSM based rules referring to the old, 129 * stale LSM policy. 130 * 131 * Update the IMA LSM based rules to reflect the reloaded LSM policy. 132 * We assume the rules still exist; and BUG_ON() if they don't. 133 */ 134 static void ima_lsm_update_rules(void) 135 { 136 struct ima_rule_entry *entry, *tmp; 137 int result; 138 int i; 139 140 mutex_lock(&ima_rules_mutex); 141 list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) { 142 for (i = 0; i < MAX_LSM_RULES; i++) { 143 if (!entry->lsm[i].rule) 144 continue; 145 result = security_filter_rule_init(entry->lsm[i].type, 146 Audit_equal, 147 entry->lsm[i].args_p, 148 &entry->lsm[i].rule); 149 BUG_ON(!entry->lsm[i].rule); 150 } 151 } 152 mutex_unlock(&ima_rules_mutex); 153 } 154 155 /** 156 * ima_match_rules - determine whether an inode matches the measure rule. 157 * @rule: a pointer to a rule 158 * @inode: a pointer to an inode 159 * @func: LIM hook identifier 160 * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC) 161 * 162 * Returns true on rule match, false on failure. 163 */ 164 static bool ima_match_rules(struct ima_rule_entry *rule, 165 struct inode *inode, enum ima_hooks func, int mask) 166 { 167 struct task_struct *tsk = current; 168 const struct cred *cred = current_cred(); 169 int i; 170 171 if ((rule->flags & IMA_FUNC) && 172 (rule->func != func && func != POST_SETATTR)) 173 return false; 174 if ((rule->flags & IMA_MASK) && 175 (rule->mask != mask && func != POST_SETATTR)) 176 return false; 177 if ((rule->flags & IMA_FSMAGIC) 178 && rule->fsmagic != inode->i_sb->s_magic) 179 return false; 180 if ((rule->flags & IMA_FSUUID) && 181 memcmp(rule->fsuuid, inode->i_sb->s_uuid, sizeof(rule->fsuuid))) 182 return false; 183 if ((rule->flags & IMA_UID) && !uid_eq(rule->uid, cred->uid)) 184 return false; 185 if ((rule->flags & IMA_FOWNER) && !uid_eq(rule->fowner, inode->i_uid)) 186 return false; 187 for (i = 0; i < MAX_LSM_RULES; i++) { 188 int rc = 0; 189 u32 osid, sid; 190 int retried = 0; 191 192 if (!rule->lsm[i].rule) 193 continue; 194 retry: 195 switch (i) { 196 case LSM_OBJ_USER: 197 case LSM_OBJ_ROLE: 198 case LSM_OBJ_TYPE: 199 security_inode_getsecid(inode, &osid); 200 rc = security_filter_rule_match(osid, 201 rule->lsm[i].type, 202 Audit_equal, 203 rule->lsm[i].rule, 204 NULL); 205 break; 206 case LSM_SUBJ_USER: 207 case LSM_SUBJ_ROLE: 208 case LSM_SUBJ_TYPE: 209 security_task_getsecid(tsk, &sid); 210 rc = security_filter_rule_match(sid, 211 rule->lsm[i].type, 212 Audit_equal, 213 rule->lsm[i].rule, 214 NULL); 215 default: 216 break; 217 } 218 if ((rc < 0) && (!retried)) { 219 retried = 1; 220 ima_lsm_update_rules(); 221 goto retry; 222 } 223 if (!rc) 224 return false; 225 } 226 return true; 227 } 228 229 /* 230 * In addition to knowing that we need to appraise the file in general, 231 * we need to differentiate between calling hooks, for hook specific rules. 232 */ 233 static int get_subaction(struct ima_rule_entry *rule, int func) 234 { 235 if (!(rule->flags & IMA_FUNC)) 236 return IMA_FILE_APPRAISE; 237 238 switch (func) { 239 case MMAP_CHECK: 240 return IMA_MMAP_APPRAISE; 241 case BPRM_CHECK: 242 return IMA_BPRM_APPRAISE; 243 case MODULE_CHECK: 244 return IMA_MODULE_APPRAISE; 245 case FIRMWARE_CHECK: 246 return IMA_FIRMWARE_APPRAISE; 247 case FILE_CHECK: 248 default: 249 return IMA_FILE_APPRAISE; 250 } 251 } 252 253 /** 254 * ima_match_policy - decision based on LSM and other conditions 255 * @inode: pointer to an inode for which the policy decision is being made 256 * @func: IMA hook identifier 257 * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC) 258 * 259 * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type) 260 * conditions. 261 * 262 * (There is no need for locking when walking the policy list, 263 * as elements in the list are never deleted, nor does the list 264 * change.) 265 */ 266 int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask, 267 int flags) 268 { 269 struct ima_rule_entry *entry; 270 int action = 0, actmask = flags | (flags << 1); 271 272 list_for_each_entry(entry, ima_rules, list) { 273 274 if (!(entry->action & actmask)) 275 continue; 276 277 if (!ima_match_rules(entry, inode, func, mask)) 278 continue; 279 280 action |= entry->flags & IMA_ACTION_FLAGS; 281 282 action |= entry->action & IMA_DO_MASK; 283 if (entry->action & IMA_APPRAISE) 284 action |= get_subaction(entry, func); 285 286 if (entry->action & IMA_DO_MASK) 287 actmask &= ~(entry->action | entry->action << 1); 288 else 289 actmask &= ~(entry->action | entry->action >> 1); 290 291 if (!actmask) 292 break; 293 } 294 295 return action; 296 } 297 298 /** 299 * ima_init_policy - initialize the default measure rules. 300 * 301 * ima_rules points to either the ima_default_rules or the 302 * the new ima_policy_rules. 303 */ 304 void __init ima_init_policy(void) 305 { 306 int i, measure_entries, appraise_entries; 307 308 /* if !ima_use_tcb set entries = 0 so we load NO default rules */ 309 measure_entries = ima_use_tcb ? ARRAY_SIZE(default_rules) : 0; 310 appraise_entries = ima_use_appraise_tcb ? 311 ARRAY_SIZE(default_appraise_rules) : 0; 312 313 for (i = 0; i < measure_entries + appraise_entries; i++) { 314 if (i < measure_entries) 315 list_add_tail(&default_rules[i].list, 316 &ima_default_rules); 317 else { 318 int j = i - measure_entries; 319 320 list_add_tail(&default_appraise_rules[j].list, 321 &ima_default_rules); 322 } 323 } 324 325 ima_rules = &ima_default_rules; 326 } 327 328 /** 329 * ima_update_policy - update default_rules with new measure rules 330 * 331 * Called on file .release to update the default rules with a complete new 332 * policy. Once updated, the policy is locked, no additional rules can be 333 * added to the policy. 334 */ 335 void ima_update_policy(void) 336 { 337 static const char op[] = "policy_update"; 338 const char *cause = "already-exists"; 339 int result = 1; 340 int audit_info = 0; 341 342 if (ima_rules == &ima_default_rules) { 343 ima_rules = &ima_policy_rules; 344 cause = "complete"; 345 result = 0; 346 } 347 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, 348 NULL, op, cause, result, audit_info); 349 } 350 351 enum { 352 Opt_err = -1, 353 Opt_measure = 1, Opt_dont_measure, 354 Opt_appraise, Opt_dont_appraise, 355 Opt_audit, 356 Opt_obj_user, Opt_obj_role, Opt_obj_type, 357 Opt_subj_user, Opt_subj_role, Opt_subj_type, 358 Opt_func, Opt_mask, Opt_fsmagic, Opt_uid, Opt_fowner, 359 Opt_appraise_type, Opt_fsuuid, Opt_permit_directio 360 }; 361 362 static match_table_t policy_tokens = { 363 {Opt_measure, "measure"}, 364 {Opt_dont_measure, "dont_measure"}, 365 {Opt_appraise, "appraise"}, 366 {Opt_dont_appraise, "dont_appraise"}, 367 {Opt_audit, "audit"}, 368 {Opt_obj_user, "obj_user=%s"}, 369 {Opt_obj_role, "obj_role=%s"}, 370 {Opt_obj_type, "obj_type=%s"}, 371 {Opt_subj_user, "subj_user=%s"}, 372 {Opt_subj_role, "subj_role=%s"}, 373 {Opt_subj_type, "subj_type=%s"}, 374 {Opt_func, "func=%s"}, 375 {Opt_mask, "mask=%s"}, 376 {Opt_fsmagic, "fsmagic=%s"}, 377 {Opt_fsuuid, "fsuuid=%s"}, 378 {Opt_uid, "uid=%s"}, 379 {Opt_fowner, "fowner=%s"}, 380 {Opt_appraise_type, "appraise_type=%s"}, 381 {Opt_permit_directio, "permit_directio"}, 382 {Opt_err, NULL} 383 }; 384 385 static int ima_lsm_rule_init(struct ima_rule_entry *entry, 386 substring_t *args, int lsm_rule, int audit_type) 387 { 388 int result; 389 390 if (entry->lsm[lsm_rule].rule) 391 return -EINVAL; 392 393 entry->lsm[lsm_rule].args_p = match_strdup(args); 394 if (!entry->lsm[lsm_rule].args_p) 395 return -ENOMEM; 396 397 entry->lsm[lsm_rule].type = audit_type; 398 result = security_filter_rule_init(entry->lsm[lsm_rule].type, 399 Audit_equal, 400 entry->lsm[lsm_rule].args_p, 401 &entry->lsm[lsm_rule].rule); 402 if (!entry->lsm[lsm_rule].rule) { 403 kfree(entry->lsm[lsm_rule].args_p); 404 return -EINVAL; 405 } 406 407 return result; 408 } 409 410 static void ima_log_string(struct audit_buffer *ab, char *key, char *value) 411 { 412 audit_log_format(ab, "%s=", key); 413 audit_log_untrustedstring(ab, value); 414 audit_log_format(ab, " "); 415 } 416 417 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) 418 { 419 struct audit_buffer *ab; 420 char *p; 421 int result = 0; 422 423 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE); 424 425 entry->uid = INVALID_UID; 426 entry->fowner = INVALID_UID; 427 entry->action = UNKNOWN; 428 while ((p = strsep(&rule, " \t")) != NULL) { 429 substring_t args[MAX_OPT_ARGS]; 430 int token; 431 unsigned long lnum; 432 433 if (result < 0) 434 break; 435 if ((*p == '\0') || (*p == ' ') || (*p == '\t')) 436 continue; 437 token = match_token(p, policy_tokens, args); 438 switch (token) { 439 case Opt_measure: 440 ima_log_string(ab, "action", "measure"); 441 442 if (entry->action != UNKNOWN) 443 result = -EINVAL; 444 445 entry->action = MEASURE; 446 break; 447 case Opt_dont_measure: 448 ima_log_string(ab, "action", "dont_measure"); 449 450 if (entry->action != UNKNOWN) 451 result = -EINVAL; 452 453 entry->action = DONT_MEASURE; 454 break; 455 case Opt_appraise: 456 ima_log_string(ab, "action", "appraise"); 457 458 if (entry->action != UNKNOWN) 459 result = -EINVAL; 460 461 entry->action = APPRAISE; 462 break; 463 case Opt_dont_appraise: 464 ima_log_string(ab, "action", "dont_appraise"); 465 466 if (entry->action != UNKNOWN) 467 result = -EINVAL; 468 469 entry->action = DONT_APPRAISE; 470 break; 471 case Opt_audit: 472 ima_log_string(ab, "action", "audit"); 473 474 if (entry->action != UNKNOWN) 475 result = -EINVAL; 476 477 entry->action = AUDIT; 478 break; 479 case Opt_func: 480 ima_log_string(ab, "func", args[0].from); 481 482 if (entry->func) 483 result = -EINVAL; 484 485 if (strcmp(args[0].from, "FILE_CHECK") == 0) 486 entry->func = FILE_CHECK; 487 /* PATH_CHECK is for backwards compat */ 488 else if (strcmp(args[0].from, "PATH_CHECK") == 0) 489 entry->func = FILE_CHECK; 490 else if (strcmp(args[0].from, "MODULE_CHECK") == 0) 491 entry->func = MODULE_CHECK; 492 else if (strcmp(args[0].from, "FIRMWARE_CHECK") == 0) 493 entry->func = FIRMWARE_CHECK; 494 else if ((strcmp(args[0].from, "FILE_MMAP") == 0) 495 || (strcmp(args[0].from, "MMAP_CHECK") == 0)) 496 entry->func = MMAP_CHECK; 497 else if (strcmp(args[0].from, "BPRM_CHECK") == 0) 498 entry->func = BPRM_CHECK; 499 else 500 result = -EINVAL; 501 if (!result) 502 entry->flags |= IMA_FUNC; 503 break; 504 case Opt_mask: 505 ima_log_string(ab, "mask", args[0].from); 506 507 if (entry->mask) 508 result = -EINVAL; 509 510 if ((strcmp(args[0].from, "MAY_EXEC")) == 0) 511 entry->mask = MAY_EXEC; 512 else if (strcmp(args[0].from, "MAY_WRITE") == 0) 513 entry->mask = MAY_WRITE; 514 else if (strcmp(args[0].from, "MAY_READ") == 0) 515 entry->mask = MAY_READ; 516 else if (strcmp(args[0].from, "MAY_APPEND") == 0) 517 entry->mask = MAY_APPEND; 518 else 519 result = -EINVAL; 520 if (!result) 521 entry->flags |= IMA_MASK; 522 break; 523 case Opt_fsmagic: 524 ima_log_string(ab, "fsmagic", args[0].from); 525 526 if (entry->fsmagic) { 527 result = -EINVAL; 528 break; 529 } 530 531 result = kstrtoul(args[0].from, 16, &entry->fsmagic); 532 if (!result) 533 entry->flags |= IMA_FSMAGIC; 534 break; 535 case Opt_fsuuid: 536 ima_log_string(ab, "fsuuid", args[0].from); 537 538 if (memchr_inv(entry->fsuuid, 0x00, 539 sizeof(entry->fsuuid))) { 540 result = -EINVAL; 541 break; 542 } 543 544 result = blk_part_pack_uuid(args[0].from, 545 entry->fsuuid); 546 if (!result) 547 entry->flags |= IMA_FSUUID; 548 break; 549 case Opt_uid: 550 ima_log_string(ab, "uid", args[0].from); 551 552 if (uid_valid(entry->uid)) { 553 result = -EINVAL; 554 break; 555 } 556 557 result = kstrtoul(args[0].from, 10, &lnum); 558 if (!result) { 559 entry->uid = make_kuid(current_user_ns(), (uid_t)lnum); 560 if (!uid_valid(entry->uid) || (((uid_t)lnum) != lnum)) 561 result = -EINVAL; 562 else 563 entry->flags |= IMA_UID; 564 } 565 break; 566 case Opt_fowner: 567 ima_log_string(ab, "fowner", args[0].from); 568 569 if (uid_valid(entry->fowner)) { 570 result = -EINVAL; 571 break; 572 } 573 574 result = kstrtoul(args[0].from, 10, &lnum); 575 if (!result) { 576 entry->fowner = make_kuid(current_user_ns(), (uid_t)lnum); 577 if (!uid_valid(entry->fowner) || (((uid_t)lnum) != lnum)) 578 result = -EINVAL; 579 else 580 entry->flags |= IMA_FOWNER; 581 } 582 break; 583 case Opt_obj_user: 584 ima_log_string(ab, "obj_user", args[0].from); 585 result = ima_lsm_rule_init(entry, args, 586 LSM_OBJ_USER, 587 AUDIT_OBJ_USER); 588 break; 589 case Opt_obj_role: 590 ima_log_string(ab, "obj_role", args[0].from); 591 result = ima_lsm_rule_init(entry, args, 592 LSM_OBJ_ROLE, 593 AUDIT_OBJ_ROLE); 594 break; 595 case Opt_obj_type: 596 ima_log_string(ab, "obj_type", args[0].from); 597 result = ima_lsm_rule_init(entry, args, 598 LSM_OBJ_TYPE, 599 AUDIT_OBJ_TYPE); 600 break; 601 case Opt_subj_user: 602 ima_log_string(ab, "subj_user", args[0].from); 603 result = ima_lsm_rule_init(entry, args, 604 LSM_SUBJ_USER, 605 AUDIT_SUBJ_USER); 606 break; 607 case Opt_subj_role: 608 ima_log_string(ab, "subj_role", args[0].from); 609 result = ima_lsm_rule_init(entry, args, 610 LSM_SUBJ_ROLE, 611 AUDIT_SUBJ_ROLE); 612 break; 613 case Opt_subj_type: 614 ima_log_string(ab, "subj_type", args[0].from); 615 result = ima_lsm_rule_init(entry, args, 616 LSM_SUBJ_TYPE, 617 AUDIT_SUBJ_TYPE); 618 break; 619 case Opt_appraise_type: 620 if (entry->action != APPRAISE) { 621 result = -EINVAL; 622 break; 623 } 624 625 ima_log_string(ab, "appraise_type", args[0].from); 626 if ((strcmp(args[0].from, "imasig")) == 0) 627 entry->flags |= IMA_DIGSIG_REQUIRED; 628 else 629 result = -EINVAL; 630 break; 631 case Opt_permit_directio: 632 entry->flags |= IMA_PERMIT_DIRECTIO; 633 break; 634 case Opt_err: 635 ima_log_string(ab, "UNKNOWN", p); 636 result = -EINVAL; 637 break; 638 } 639 } 640 if (!result && (entry->action == UNKNOWN)) 641 result = -EINVAL; 642 else if (entry->func == MODULE_CHECK) 643 ima_appraise |= IMA_APPRAISE_MODULES; 644 else if (entry->func == FIRMWARE_CHECK) 645 ima_appraise |= IMA_APPRAISE_FIRMWARE; 646 audit_log_format(ab, "res=%d", !result); 647 audit_log_end(ab); 648 return result; 649 } 650 651 /** 652 * ima_parse_add_rule - add a rule to ima_policy_rules 653 * @rule - ima measurement policy rule 654 * 655 * Uses a mutex to protect the policy list from multiple concurrent writers. 656 * Returns the length of the rule parsed, an error code on failure 657 */ 658 ssize_t ima_parse_add_rule(char *rule) 659 { 660 static const char op[] = "update_policy"; 661 char *p; 662 struct ima_rule_entry *entry; 663 ssize_t result, len; 664 int audit_info = 0; 665 666 /* Prevent installed policy from changing */ 667 if (ima_rules != &ima_default_rules) { 668 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, 669 NULL, op, "already-exists", 670 -EACCES, audit_info); 671 return -EACCES; 672 } 673 674 entry = kzalloc(sizeof(*entry), GFP_KERNEL); 675 if (!entry) { 676 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, 677 NULL, op, "-ENOMEM", -ENOMEM, audit_info); 678 return -ENOMEM; 679 } 680 681 INIT_LIST_HEAD(&entry->list); 682 683 p = strsep(&rule, "\n"); 684 len = strlen(p) + 1; 685 686 if (*p == '#') { 687 kfree(entry); 688 return len; 689 } 690 691 result = ima_parse_rule(p, entry); 692 if (result) { 693 kfree(entry); 694 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, 695 NULL, op, "invalid-policy", result, 696 audit_info); 697 return result; 698 } 699 700 mutex_lock(&ima_rules_mutex); 701 list_add_tail(&entry->list, &ima_policy_rules); 702 mutex_unlock(&ima_rules_mutex); 703 704 return len; 705 } 706 707 /* ima_delete_rules called to cleanup invalid policy */ 708 void ima_delete_rules(void) 709 { 710 struct ima_rule_entry *entry, *tmp; 711 int i; 712 713 mutex_lock(&ima_rules_mutex); 714 list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) { 715 for (i = 0; i < MAX_LSM_RULES; i++) 716 kfree(entry->lsm[i].args_p); 717 718 list_del(&entry->list); 719 kfree(entry); 720 } 721 mutex_unlock(&ima_rules_mutex); 722 } 723