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/fs.h> 16 #include <linux/security.h> 17 #include <linux/magic.h> 18 #include <linux/parser.h> 19 #include <linux/slab.h> 20 #include <linux/rculist.h> 21 #include <linux/genhd.h> 22 #include <linux/seq_file.h> 23 24 #include "ima.h" 25 26 /* flags definitions */ 27 #define IMA_FUNC 0x0001 28 #define IMA_MASK 0x0002 29 #define IMA_FSMAGIC 0x0004 30 #define IMA_UID 0x0008 31 #define IMA_FOWNER 0x0010 32 #define IMA_FSUUID 0x0020 33 #define IMA_INMASK 0x0040 34 #define IMA_EUID 0x0080 35 #define IMA_PCR 0x0100 36 37 #define UNKNOWN 0 38 #define MEASURE 0x0001 /* same as IMA_MEASURE */ 39 #define DONT_MEASURE 0x0002 40 #define APPRAISE 0x0004 /* same as IMA_APPRAISE */ 41 #define DONT_APPRAISE 0x0008 42 #define AUDIT 0x0040 43 #define HASH 0x0100 44 #define DONT_HASH 0x0200 45 46 #define INVALID_PCR(a) (((a) < 0) || \ 47 (a) >= (FIELD_SIZEOF(struct integrity_iint_cache, measured_pcrs) * 8)) 48 49 int ima_policy_flag; 50 static int temp_ima_appraise; 51 52 #define MAX_LSM_RULES 6 53 enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE, 54 LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE 55 }; 56 57 enum policy_types { ORIGINAL_TCB = 1, DEFAULT_TCB }; 58 59 struct ima_rule_entry { 60 struct list_head list; 61 int action; 62 unsigned int flags; 63 enum ima_hooks func; 64 int mask; 65 unsigned long fsmagic; 66 uuid_t fsuuid; 67 kuid_t uid; 68 kuid_t fowner; 69 bool (*uid_op)(kuid_t, kuid_t); /* Handlers for operators */ 70 bool (*fowner_op)(kuid_t, kuid_t); /* uid_eq(), uid_gt(), uid_lt() */ 71 int pcr; 72 struct { 73 void *rule; /* LSM file metadata specific */ 74 void *args_p; /* audit value */ 75 int type; /* audit type */ 76 } lsm[MAX_LSM_RULES]; 77 }; 78 79 /* 80 * Without LSM specific knowledge, the default policy can only be 81 * written in terms of .action, .func, .mask, .fsmagic, .uid, and .fowner 82 */ 83 84 /* 85 * The minimum rule set to allow for full TCB coverage. Measures all files 86 * opened or mmap for exec and everything read by root. Dangerous because 87 * normal users can easily run the machine out of memory simply building 88 * and running executables. 89 */ 90 static struct ima_rule_entry dont_measure_rules[] __ro_after_init = { 91 {.action = DONT_MEASURE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC}, 92 {.action = DONT_MEASURE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC}, 93 {.action = DONT_MEASURE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC}, 94 {.action = DONT_MEASURE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC}, 95 {.action = DONT_MEASURE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC}, 96 {.action = DONT_MEASURE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC}, 97 {.action = DONT_MEASURE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC}, 98 {.action = DONT_MEASURE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC}, 99 {.action = DONT_MEASURE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC}, 100 {.action = DONT_MEASURE, .fsmagic = CGROUP_SUPER_MAGIC, 101 .flags = IMA_FSMAGIC}, 102 {.action = DONT_MEASURE, .fsmagic = CGROUP2_SUPER_MAGIC, 103 .flags = IMA_FSMAGIC}, 104 {.action = DONT_MEASURE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC} 105 }; 106 107 static struct ima_rule_entry original_measurement_rules[] __ro_after_init = { 108 {.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC, 109 .flags = IMA_FUNC | IMA_MASK}, 110 {.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC, 111 .flags = IMA_FUNC | IMA_MASK}, 112 {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ, 113 .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq, 114 .flags = IMA_FUNC | IMA_MASK | IMA_UID}, 115 {.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC}, 116 {.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC}, 117 }; 118 119 static struct ima_rule_entry default_measurement_rules[] __ro_after_init = { 120 {.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC, 121 .flags = IMA_FUNC | IMA_MASK}, 122 {.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC, 123 .flags = IMA_FUNC | IMA_MASK}, 124 {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ, 125 .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq, 126 .flags = IMA_FUNC | IMA_INMASK | IMA_EUID}, 127 {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ, 128 .uid = GLOBAL_ROOT_UID, .uid_op = &uid_eq, 129 .flags = IMA_FUNC | IMA_INMASK | IMA_UID}, 130 {.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC}, 131 {.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC}, 132 {.action = MEASURE, .func = POLICY_CHECK, .flags = IMA_FUNC}, 133 }; 134 135 static struct ima_rule_entry default_appraise_rules[] __ro_after_init = { 136 {.action = DONT_APPRAISE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC}, 137 {.action = DONT_APPRAISE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC}, 138 {.action = DONT_APPRAISE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC}, 139 {.action = DONT_APPRAISE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC}, 140 {.action = DONT_APPRAISE, .fsmagic = RAMFS_MAGIC, .flags = IMA_FSMAGIC}, 141 {.action = DONT_APPRAISE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC}, 142 {.action = DONT_APPRAISE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC}, 143 {.action = DONT_APPRAISE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC}, 144 {.action = DONT_APPRAISE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC}, 145 {.action = DONT_APPRAISE, .fsmagic = SMACK_MAGIC, .flags = IMA_FSMAGIC}, 146 {.action = DONT_APPRAISE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC}, 147 {.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC}, 148 {.action = DONT_APPRAISE, .fsmagic = CGROUP2_SUPER_MAGIC, .flags = IMA_FSMAGIC}, 149 #ifdef CONFIG_IMA_WRITE_POLICY 150 {.action = APPRAISE, .func = POLICY_CHECK, 151 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED}, 152 #endif 153 #ifndef CONFIG_IMA_APPRAISE_SIGNED_INIT 154 {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &uid_eq, 155 .flags = IMA_FOWNER}, 156 #else 157 /* force signature */ 158 {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .fowner_op = &uid_eq, 159 .flags = IMA_FOWNER | IMA_DIGSIG_REQUIRED}, 160 #endif 161 }; 162 163 static struct ima_rule_entry secure_boot_rules[] __ro_after_init = { 164 {.action = APPRAISE, .func = MODULE_CHECK, 165 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED}, 166 {.action = APPRAISE, .func = FIRMWARE_CHECK, 167 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED}, 168 {.action = APPRAISE, .func = KEXEC_KERNEL_CHECK, 169 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED}, 170 {.action = APPRAISE, .func = POLICY_CHECK, 171 .flags = IMA_FUNC | IMA_DIGSIG_REQUIRED}, 172 }; 173 174 static LIST_HEAD(ima_default_rules); 175 static LIST_HEAD(ima_policy_rules); 176 static LIST_HEAD(ima_temp_rules); 177 static struct list_head *ima_rules; 178 179 static int ima_policy __initdata; 180 181 static int __init default_measure_policy_setup(char *str) 182 { 183 if (ima_policy) 184 return 1; 185 186 ima_policy = ORIGINAL_TCB; 187 return 1; 188 } 189 __setup("ima_tcb", default_measure_policy_setup); 190 191 static bool ima_use_appraise_tcb __initdata; 192 static bool ima_use_secure_boot __initdata; 193 static bool ima_fail_unverifiable_sigs __ro_after_init; 194 static int __init policy_setup(char *str) 195 { 196 char *p; 197 198 while ((p = strsep(&str, " |\n")) != NULL) { 199 if (*p == ' ') 200 continue; 201 if ((strcmp(p, "tcb") == 0) && !ima_policy) 202 ima_policy = DEFAULT_TCB; 203 else if (strcmp(p, "appraise_tcb") == 0) 204 ima_use_appraise_tcb = true; 205 else if (strcmp(p, "secure_boot") == 0) 206 ima_use_secure_boot = true; 207 else if (strcmp(p, "fail_securely") == 0) 208 ima_fail_unverifiable_sigs = true; 209 } 210 211 return 1; 212 } 213 __setup("ima_policy=", policy_setup); 214 215 static int __init default_appraise_policy_setup(char *str) 216 { 217 ima_use_appraise_tcb = true; 218 return 1; 219 } 220 __setup("ima_appraise_tcb", default_appraise_policy_setup); 221 222 /* 223 * The LSM policy can be reloaded, leaving the IMA LSM based rules referring 224 * to the old, stale LSM policy. Update the IMA LSM based rules to reflect 225 * the reloaded LSM policy. We assume the rules still exist; and BUG_ON() if 226 * they don't. 227 */ 228 static void ima_lsm_update_rules(void) 229 { 230 struct ima_rule_entry *entry; 231 int result; 232 int i; 233 234 list_for_each_entry(entry, &ima_policy_rules, list) { 235 for (i = 0; i < MAX_LSM_RULES; i++) { 236 if (!entry->lsm[i].rule) 237 continue; 238 result = security_filter_rule_init(entry->lsm[i].type, 239 Audit_equal, 240 entry->lsm[i].args_p, 241 &entry->lsm[i].rule); 242 BUG_ON(!entry->lsm[i].rule); 243 } 244 } 245 } 246 247 /** 248 * ima_match_rules - determine whether an inode matches the measure rule. 249 * @rule: a pointer to a rule 250 * @inode: a pointer to an inode 251 * @cred: a pointer to a credentials structure for user validation 252 * @secid: the secid of the task to be validated 253 * @func: LIM hook identifier 254 * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC) 255 * 256 * Returns true on rule match, false on failure. 257 */ 258 static bool ima_match_rules(struct ima_rule_entry *rule, struct inode *inode, 259 const struct cred *cred, u32 secid, 260 enum ima_hooks func, int mask) 261 { 262 int i; 263 264 if ((rule->flags & IMA_FUNC) && 265 (rule->func != func && func != POST_SETATTR)) 266 return false; 267 if ((rule->flags & IMA_MASK) && 268 (rule->mask != mask && func != POST_SETATTR)) 269 return false; 270 if ((rule->flags & IMA_INMASK) && 271 (!(rule->mask & mask) && func != POST_SETATTR)) 272 return false; 273 if ((rule->flags & IMA_FSMAGIC) 274 && rule->fsmagic != inode->i_sb->s_magic) 275 return false; 276 if ((rule->flags & IMA_FSUUID) && 277 !uuid_equal(&rule->fsuuid, &inode->i_sb->s_uuid)) 278 return false; 279 if ((rule->flags & IMA_UID) && !rule->uid_op(cred->uid, rule->uid)) 280 return false; 281 if (rule->flags & IMA_EUID) { 282 if (has_capability_noaudit(current, CAP_SETUID)) { 283 if (!rule->uid_op(cred->euid, rule->uid) 284 && !rule->uid_op(cred->suid, rule->uid) 285 && !rule->uid_op(cred->uid, rule->uid)) 286 return false; 287 } else if (!rule->uid_op(cred->euid, rule->uid)) 288 return false; 289 } 290 291 if ((rule->flags & IMA_FOWNER) && 292 !rule->fowner_op(inode->i_uid, rule->fowner)) 293 return false; 294 for (i = 0; i < MAX_LSM_RULES; i++) { 295 int rc = 0; 296 u32 osid; 297 int retried = 0; 298 299 if (!rule->lsm[i].rule) 300 continue; 301 retry: 302 switch (i) { 303 case LSM_OBJ_USER: 304 case LSM_OBJ_ROLE: 305 case LSM_OBJ_TYPE: 306 security_inode_getsecid(inode, &osid); 307 rc = security_filter_rule_match(osid, 308 rule->lsm[i].type, 309 Audit_equal, 310 rule->lsm[i].rule, 311 NULL); 312 break; 313 case LSM_SUBJ_USER: 314 case LSM_SUBJ_ROLE: 315 case LSM_SUBJ_TYPE: 316 rc = security_filter_rule_match(secid, 317 rule->lsm[i].type, 318 Audit_equal, 319 rule->lsm[i].rule, 320 NULL); 321 default: 322 break; 323 } 324 if ((rc < 0) && (!retried)) { 325 retried = 1; 326 ima_lsm_update_rules(); 327 goto retry; 328 } 329 if (!rc) 330 return false; 331 } 332 return true; 333 } 334 335 /* 336 * In addition to knowing that we need to appraise the file in general, 337 * we need to differentiate between calling hooks, for hook specific rules. 338 */ 339 static int get_subaction(struct ima_rule_entry *rule, enum ima_hooks func) 340 { 341 if (!(rule->flags & IMA_FUNC)) 342 return IMA_FILE_APPRAISE; 343 344 switch (func) { 345 case MMAP_CHECK: 346 return IMA_MMAP_APPRAISE; 347 case BPRM_CHECK: 348 return IMA_BPRM_APPRAISE; 349 case CREDS_CHECK: 350 return IMA_CREDS_APPRAISE; 351 case FILE_CHECK: 352 case POST_SETATTR: 353 return IMA_FILE_APPRAISE; 354 case MODULE_CHECK ... MAX_CHECK - 1: 355 default: 356 return IMA_READ_APPRAISE; 357 } 358 } 359 360 /** 361 * ima_match_policy - decision based on LSM and other conditions 362 * @inode: pointer to an inode for which the policy decision is being made 363 * @cred: pointer to a credentials structure for which the policy decision is 364 * being made 365 * @secid: LSM secid of the task to be validated 366 * @func: IMA hook identifier 367 * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC) 368 * @pcr: set the pcr to extend 369 * 370 * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type) 371 * conditions. 372 * 373 * Since the IMA policy may be updated multiple times we need to lock the 374 * list when walking it. Reads are many orders of magnitude more numerous 375 * than writes so ima_match_policy() is classical RCU candidate. 376 */ 377 int ima_match_policy(struct inode *inode, const struct cred *cred, u32 secid, 378 enum ima_hooks func, int mask, int flags, int *pcr) 379 { 380 struct ima_rule_entry *entry; 381 int action = 0, actmask = flags | (flags << 1); 382 383 rcu_read_lock(); 384 list_for_each_entry_rcu(entry, ima_rules, list) { 385 386 if (!(entry->action & actmask)) 387 continue; 388 389 if (!ima_match_rules(entry, inode, cred, secid, func, mask)) 390 continue; 391 392 action |= entry->flags & IMA_ACTION_FLAGS; 393 394 action |= entry->action & IMA_DO_MASK; 395 if (entry->action & IMA_APPRAISE) { 396 action |= get_subaction(entry, func); 397 action &= ~IMA_HASH; 398 if (ima_fail_unverifiable_sigs) 399 action |= IMA_FAIL_UNVERIFIABLE_SIGS; 400 } 401 402 if (entry->action & IMA_DO_MASK) 403 actmask &= ~(entry->action | entry->action << 1); 404 else 405 actmask &= ~(entry->action | entry->action >> 1); 406 407 if ((pcr) && (entry->flags & IMA_PCR)) 408 *pcr = entry->pcr; 409 410 if (!actmask) 411 break; 412 } 413 rcu_read_unlock(); 414 415 return action; 416 } 417 418 /* 419 * Initialize the ima_policy_flag variable based on the currently 420 * loaded policy. Based on this flag, the decision to short circuit 421 * out of a function or not call the function in the first place 422 * can be made earlier. 423 */ 424 void ima_update_policy_flag(void) 425 { 426 struct ima_rule_entry *entry; 427 428 list_for_each_entry(entry, ima_rules, list) { 429 if (entry->action & IMA_DO_MASK) 430 ima_policy_flag |= entry->action; 431 } 432 433 ima_appraise |= temp_ima_appraise; 434 if (!ima_appraise) 435 ima_policy_flag &= ~IMA_APPRAISE; 436 } 437 438 /** 439 * ima_init_policy - initialize the default measure rules. 440 * 441 * ima_rules points to either the ima_default_rules or the 442 * the new ima_policy_rules. 443 */ 444 void __init ima_init_policy(void) 445 { 446 int i, measure_entries, appraise_entries, secure_boot_entries; 447 448 /* if !ima_policy set entries = 0 so we load NO default rules */ 449 measure_entries = ima_policy ? ARRAY_SIZE(dont_measure_rules) : 0; 450 appraise_entries = ima_use_appraise_tcb ? 451 ARRAY_SIZE(default_appraise_rules) : 0; 452 secure_boot_entries = ima_use_secure_boot ? 453 ARRAY_SIZE(secure_boot_rules) : 0; 454 455 for (i = 0; i < measure_entries; i++) 456 list_add_tail(&dont_measure_rules[i].list, &ima_default_rules); 457 458 switch (ima_policy) { 459 case ORIGINAL_TCB: 460 for (i = 0; i < ARRAY_SIZE(original_measurement_rules); i++) 461 list_add_tail(&original_measurement_rules[i].list, 462 &ima_default_rules); 463 break; 464 case DEFAULT_TCB: 465 for (i = 0; i < ARRAY_SIZE(default_measurement_rules); i++) 466 list_add_tail(&default_measurement_rules[i].list, 467 &ima_default_rules); 468 default: 469 break; 470 } 471 472 /* 473 * Insert the appraise rules requiring file signatures, prior to 474 * any other appraise rules. 475 */ 476 for (i = 0; i < secure_boot_entries; i++) 477 list_add_tail(&secure_boot_rules[i].list, 478 &ima_default_rules); 479 480 for (i = 0; i < appraise_entries; i++) { 481 list_add_tail(&default_appraise_rules[i].list, 482 &ima_default_rules); 483 if (default_appraise_rules[i].func == POLICY_CHECK) 484 temp_ima_appraise |= IMA_APPRAISE_POLICY; 485 } 486 487 ima_rules = &ima_default_rules; 488 ima_update_policy_flag(); 489 } 490 491 /* Make sure we have a valid policy, at least containing some rules. */ 492 int ima_check_policy(void) 493 { 494 if (list_empty(&ima_temp_rules)) 495 return -EINVAL; 496 return 0; 497 } 498 499 /** 500 * ima_update_policy - update default_rules with new measure rules 501 * 502 * Called on file .release to update the default rules with a complete new 503 * policy. What we do here is to splice ima_policy_rules and ima_temp_rules so 504 * they make a queue. The policy may be updated multiple times and this is the 505 * RCU updater. 506 * 507 * Policy rules are never deleted so ima_policy_flag gets zeroed only once when 508 * we switch from the default policy to user defined. 509 */ 510 void ima_update_policy(void) 511 { 512 struct list_head *first, *last, *policy; 513 514 /* append current policy with the new rules */ 515 first = (&ima_temp_rules)->next; 516 last = (&ima_temp_rules)->prev; 517 policy = &ima_policy_rules; 518 519 synchronize_rcu(); 520 521 last->next = policy; 522 rcu_assign_pointer(list_next_rcu(policy->prev), first); 523 first->prev = policy->prev; 524 policy->prev = last; 525 526 /* prepare for the next policy rules addition */ 527 INIT_LIST_HEAD(&ima_temp_rules); 528 529 if (ima_rules != policy) { 530 ima_policy_flag = 0; 531 ima_rules = policy; 532 } 533 ima_update_policy_flag(); 534 } 535 536 enum { 537 Opt_err = -1, 538 Opt_measure = 1, Opt_dont_measure, 539 Opt_appraise, Opt_dont_appraise, 540 Opt_audit, Opt_hash, Opt_dont_hash, 541 Opt_obj_user, Opt_obj_role, Opt_obj_type, 542 Opt_subj_user, Opt_subj_role, Opt_subj_type, 543 Opt_func, Opt_mask, Opt_fsmagic, 544 Opt_fsuuid, Opt_uid_eq, Opt_euid_eq, Opt_fowner_eq, 545 Opt_uid_gt, Opt_euid_gt, Opt_fowner_gt, 546 Opt_uid_lt, Opt_euid_lt, Opt_fowner_lt, 547 Opt_appraise_type, Opt_permit_directio, 548 Opt_pcr 549 }; 550 551 static match_table_t policy_tokens = { 552 {Opt_measure, "measure"}, 553 {Opt_dont_measure, "dont_measure"}, 554 {Opt_appraise, "appraise"}, 555 {Opt_dont_appraise, "dont_appraise"}, 556 {Opt_audit, "audit"}, 557 {Opt_hash, "hash"}, 558 {Opt_dont_hash, "dont_hash"}, 559 {Opt_obj_user, "obj_user=%s"}, 560 {Opt_obj_role, "obj_role=%s"}, 561 {Opt_obj_type, "obj_type=%s"}, 562 {Opt_subj_user, "subj_user=%s"}, 563 {Opt_subj_role, "subj_role=%s"}, 564 {Opt_subj_type, "subj_type=%s"}, 565 {Opt_func, "func=%s"}, 566 {Opt_mask, "mask=%s"}, 567 {Opt_fsmagic, "fsmagic=%s"}, 568 {Opt_fsuuid, "fsuuid=%s"}, 569 {Opt_uid_eq, "uid=%s"}, 570 {Opt_euid_eq, "euid=%s"}, 571 {Opt_fowner_eq, "fowner=%s"}, 572 {Opt_uid_gt, "uid>%s"}, 573 {Opt_euid_gt, "euid>%s"}, 574 {Opt_fowner_gt, "fowner>%s"}, 575 {Opt_uid_lt, "uid<%s"}, 576 {Opt_euid_lt, "euid<%s"}, 577 {Opt_fowner_lt, "fowner<%s"}, 578 {Opt_appraise_type, "appraise_type=%s"}, 579 {Opt_permit_directio, "permit_directio"}, 580 {Opt_pcr, "pcr=%s"}, 581 {Opt_err, NULL} 582 }; 583 584 static int ima_lsm_rule_init(struct ima_rule_entry *entry, 585 substring_t *args, int lsm_rule, int audit_type) 586 { 587 int result; 588 589 if (entry->lsm[lsm_rule].rule) 590 return -EINVAL; 591 592 entry->lsm[lsm_rule].args_p = match_strdup(args); 593 if (!entry->lsm[lsm_rule].args_p) 594 return -ENOMEM; 595 596 entry->lsm[lsm_rule].type = audit_type; 597 result = security_filter_rule_init(entry->lsm[lsm_rule].type, 598 Audit_equal, 599 entry->lsm[lsm_rule].args_p, 600 &entry->lsm[lsm_rule].rule); 601 if (!entry->lsm[lsm_rule].rule) { 602 kfree(entry->lsm[lsm_rule].args_p); 603 return -EINVAL; 604 } 605 606 return result; 607 } 608 609 static void ima_log_string_op(struct audit_buffer *ab, char *key, char *value, 610 bool (*rule_operator)(kuid_t, kuid_t)) 611 { 612 if (rule_operator == &uid_gt) 613 audit_log_format(ab, "%s>", key); 614 else if (rule_operator == &uid_lt) 615 audit_log_format(ab, "%s<", key); 616 else 617 audit_log_format(ab, "%s=", key); 618 audit_log_untrustedstring(ab, value); 619 audit_log_format(ab, " "); 620 } 621 static void ima_log_string(struct audit_buffer *ab, char *key, char *value) 622 { 623 ima_log_string_op(ab, key, value, NULL); 624 } 625 626 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry) 627 { 628 struct audit_buffer *ab; 629 char *from; 630 char *p; 631 bool uid_token; 632 int result = 0; 633 634 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE); 635 636 entry->uid = INVALID_UID; 637 entry->fowner = INVALID_UID; 638 entry->uid_op = &uid_eq; 639 entry->fowner_op = &uid_eq; 640 entry->action = UNKNOWN; 641 while ((p = strsep(&rule, " \t")) != NULL) { 642 substring_t args[MAX_OPT_ARGS]; 643 int token; 644 unsigned long lnum; 645 646 if (result < 0) 647 break; 648 if ((*p == '\0') || (*p == ' ') || (*p == '\t')) 649 continue; 650 token = match_token(p, policy_tokens, args); 651 switch (token) { 652 case Opt_measure: 653 ima_log_string(ab, "action", "measure"); 654 655 if (entry->action != UNKNOWN) 656 result = -EINVAL; 657 658 entry->action = MEASURE; 659 break; 660 case Opt_dont_measure: 661 ima_log_string(ab, "action", "dont_measure"); 662 663 if (entry->action != UNKNOWN) 664 result = -EINVAL; 665 666 entry->action = DONT_MEASURE; 667 break; 668 case Opt_appraise: 669 ima_log_string(ab, "action", "appraise"); 670 671 if (entry->action != UNKNOWN) 672 result = -EINVAL; 673 674 entry->action = APPRAISE; 675 break; 676 case Opt_dont_appraise: 677 ima_log_string(ab, "action", "dont_appraise"); 678 679 if (entry->action != UNKNOWN) 680 result = -EINVAL; 681 682 entry->action = DONT_APPRAISE; 683 break; 684 case Opt_audit: 685 ima_log_string(ab, "action", "audit"); 686 687 if (entry->action != UNKNOWN) 688 result = -EINVAL; 689 690 entry->action = AUDIT; 691 break; 692 case Opt_hash: 693 ima_log_string(ab, "action", "hash"); 694 695 if (entry->action != UNKNOWN) 696 result = -EINVAL; 697 698 entry->action = HASH; 699 break; 700 case Opt_dont_hash: 701 ima_log_string(ab, "action", "dont_hash"); 702 703 if (entry->action != UNKNOWN) 704 result = -EINVAL; 705 706 entry->action = DONT_HASH; 707 break; 708 case Opt_func: 709 ima_log_string(ab, "func", args[0].from); 710 711 if (entry->func) 712 result = -EINVAL; 713 714 if (strcmp(args[0].from, "FILE_CHECK") == 0) 715 entry->func = FILE_CHECK; 716 /* PATH_CHECK is for backwards compat */ 717 else if (strcmp(args[0].from, "PATH_CHECK") == 0) 718 entry->func = FILE_CHECK; 719 else if (strcmp(args[0].from, "MODULE_CHECK") == 0) 720 entry->func = MODULE_CHECK; 721 else if (strcmp(args[0].from, "FIRMWARE_CHECK") == 0) 722 entry->func = FIRMWARE_CHECK; 723 else if ((strcmp(args[0].from, "FILE_MMAP") == 0) 724 || (strcmp(args[0].from, "MMAP_CHECK") == 0)) 725 entry->func = MMAP_CHECK; 726 else if (strcmp(args[0].from, "BPRM_CHECK") == 0) 727 entry->func = BPRM_CHECK; 728 else if (strcmp(args[0].from, "CREDS_CHECK") == 0) 729 entry->func = CREDS_CHECK; 730 else if (strcmp(args[0].from, "KEXEC_KERNEL_CHECK") == 731 0) 732 entry->func = KEXEC_KERNEL_CHECK; 733 else if (strcmp(args[0].from, "KEXEC_INITRAMFS_CHECK") 734 == 0) 735 entry->func = KEXEC_INITRAMFS_CHECK; 736 else if (strcmp(args[0].from, "POLICY_CHECK") == 0) 737 entry->func = POLICY_CHECK; 738 else 739 result = -EINVAL; 740 if (!result) 741 entry->flags |= IMA_FUNC; 742 break; 743 case Opt_mask: 744 ima_log_string(ab, "mask", args[0].from); 745 746 if (entry->mask) 747 result = -EINVAL; 748 749 from = args[0].from; 750 if (*from == '^') 751 from++; 752 753 if ((strcmp(from, "MAY_EXEC")) == 0) 754 entry->mask = MAY_EXEC; 755 else if (strcmp(from, "MAY_WRITE") == 0) 756 entry->mask = MAY_WRITE; 757 else if (strcmp(from, "MAY_READ") == 0) 758 entry->mask = MAY_READ; 759 else if (strcmp(from, "MAY_APPEND") == 0) 760 entry->mask = MAY_APPEND; 761 else 762 result = -EINVAL; 763 if (!result) 764 entry->flags |= (*args[0].from == '^') 765 ? IMA_INMASK : IMA_MASK; 766 break; 767 case Opt_fsmagic: 768 ima_log_string(ab, "fsmagic", args[0].from); 769 770 if (entry->fsmagic) { 771 result = -EINVAL; 772 break; 773 } 774 775 result = kstrtoul(args[0].from, 16, &entry->fsmagic); 776 if (!result) 777 entry->flags |= IMA_FSMAGIC; 778 break; 779 case Opt_fsuuid: 780 ima_log_string(ab, "fsuuid", args[0].from); 781 782 if (!uuid_is_null(&entry->fsuuid)) { 783 result = -EINVAL; 784 break; 785 } 786 787 result = uuid_parse(args[0].from, &entry->fsuuid); 788 if (!result) 789 entry->flags |= IMA_FSUUID; 790 break; 791 case Opt_uid_gt: 792 case Opt_euid_gt: 793 entry->uid_op = &uid_gt; 794 case Opt_uid_lt: 795 case Opt_euid_lt: 796 if ((token == Opt_uid_lt) || (token == Opt_euid_lt)) 797 entry->uid_op = &uid_lt; 798 case Opt_uid_eq: 799 case Opt_euid_eq: 800 uid_token = (token == Opt_uid_eq) || 801 (token == Opt_uid_gt) || 802 (token == Opt_uid_lt); 803 804 ima_log_string_op(ab, uid_token ? "uid" : "euid", 805 args[0].from, entry->uid_op); 806 807 if (uid_valid(entry->uid)) { 808 result = -EINVAL; 809 break; 810 } 811 812 result = kstrtoul(args[0].from, 10, &lnum); 813 if (!result) { 814 entry->uid = make_kuid(current_user_ns(), 815 (uid_t) lnum); 816 if (!uid_valid(entry->uid) || 817 (uid_t)lnum != lnum) 818 result = -EINVAL; 819 else 820 entry->flags |= uid_token 821 ? IMA_UID : IMA_EUID; 822 } 823 break; 824 case Opt_fowner_gt: 825 entry->fowner_op = &uid_gt; 826 case Opt_fowner_lt: 827 if (token == Opt_fowner_lt) 828 entry->fowner_op = &uid_lt; 829 case Opt_fowner_eq: 830 ima_log_string_op(ab, "fowner", args[0].from, 831 entry->fowner_op); 832 833 if (uid_valid(entry->fowner)) { 834 result = -EINVAL; 835 break; 836 } 837 838 result = kstrtoul(args[0].from, 10, &lnum); 839 if (!result) { 840 entry->fowner = make_kuid(current_user_ns(), (uid_t)lnum); 841 if (!uid_valid(entry->fowner) || (((uid_t)lnum) != lnum)) 842 result = -EINVAL; 843 else 844 entry->flags |= IMA_FOWNER; 845 } 846 break; 847 case Opt_obj_user: 848 ima_log_string(ab, "obj_user", args[0].from); 849 result = ima_lsm_rule_init(entry, args, 850 LSM_OBJ_USER, 851 AUDIT_OBJ_USER); 852 break; 853 case Opt_obj_role: 854 ima_log_string(ab, "obj_role", args[0].from); 855 result = ima_lsm_rule_init(entry, args, 856 LSM_OBJ_ROLE, 857 AUDIT_OBJ_ROLE); 858 break; 859 case Opt_obj_type: 860 ima_log_string(ab, "obj_type", args[0].from); 861 result = ima_lsm_rule_init(entry, args, 862 LSM_OBJ_TYPE, 863 AUDIT_OBJ_TYPE); 864 break; 865 case Opt_subj_user: 866 ima_log_string(ab, "subj_user", args[0].from); 867 result = ima_lsm_rule_init(entry, args, 868 LSM_SUBJ_USER, 869 AUDIT_SUBJ_USER); 870 break; 871 case Opt_subj_role: 872 ima_log_string(ab, "subj_role", args[0].from); 873 result = ima_lsm_rule_init(entry, args, 874 LSM_SUBJ_ROLE, 875 AUDIT_SUBJ_ROLE); 876 break; 877 case Opt_subj_type: 878 ima_log_string(ab, "subj_type", args[0].from); 879 result = ima_lsm_rule_init(entry, args, 880 LSM_SUBJ_TYPE, 881 AUDIT_SUBJ_TYPE); 882 break; 883 case Opt_appraise_type: 884 if (entry->action != APPRAISE) { 885 result = -EINVAL; 886 break; 887 } 888 889 ima_log_string(ab, "appraise_type", args[0].from); 890 if ((strcmp(args[0].from, "imasig")) == 0) 891 entry->flags |= IMA_DIGSIG_REQUIRED; 892 else 893 result = -EINVAL; 894 break; 895 case Opt_permit_directio: 896 entry->flags |= IMA_PERMIT_DIRECTIO; 897 break; 898 case Opt_pcr: 899 if (entry->action != MEASURE) { 900 result = -EINVAL; 901 break; 902 } 903 ima_log_string(ab, "pcr", args[0].from); 904 905 result = kstrtoint(args[0].from, 10, &entry->pcr); 906 if (result || INVALID_PCR(entry->pcr)) 907 result = -EINVAL; 908 else 909 entry->flags |= IMA_PCR; 910 911 break; 912 case Opt_err: 913 ima_log_string(ab, "UNKNOWN", p); 914 result = -EINVAL; 915 break; 916 } 917 } 918 if (!result && (entry->action == UNKNOWN)) 919 result = -EINVAL; 920 else if (entry->func == MODULE_CHECK) 921 temp_ima_appraise |= IMA_APPRAISE_MODULES; 922 else if (entry->func == FIRMWARE_CHECK) 923 temp_ima_appraise |= IMA_APPRAISE_FIRMWARE; 924 else if (entry->func == POLICY_CHECK) 925 temp_ima_appraise |= IMA_APPRAISE_POLICY; 926 audit_log_format(ab, "res=%d", !result); 927 audit_log_end(ab); 928 return result; 929 } 930 931 /** 932 * ima_parse_add_rule - add a rule to ima_policy_rules 933 * @rule - ima measurement policy rule 934 * 935 * Avoid locking by allowing just one writer at a time in ima_write_policy() 936 * Returns the length of the rule parsed, an error code on failure 937 */ 938 ssize_t ima_parse_add_rule(char *rule) 939 { 940 static const char op[] = "update_policy"; 941 char *p; 942 struct ima_rule_entry *entry; 943 ssize_t result, len; 944 int audit_info = 0; 945 946 p = strsep(&rule, "\n"); 947 len = strlen(p) + 1; 948 p += strspn(p, " \t"); 949 950 if (*p == '#' || *p == '\0') 951 return len; 952 953 entry = kzalloc(sizeof(*entry), GFP_KERNEL); 954 if (!entry) { 955 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, 956 NULL, op, "-ENOMEM", -ENOMEM, audit_info); 957 return -ENOMEM; 958 } 959 960 INIT_LIST_HEAD(&entry->list); 961 962 result = ima_parse_rule(p, entry); 963 if (result) { 964 kfree(entry); 965 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, 966 NULL, op, "invalid-policy", result, 967 audit_info); 968 return result; 969 } 970 971 list_add_tail(&entry->list, &ima_temp_rules); 972 973 return len; 974 } 975 976 /** 977 * ima_delete_rules() called to cleanup invalid in-flight policy. 978 * We don't need locking as we operate on the temp list, which is 979 * different from the active one. There is also only one user of 980 * ima_delete_rules() at a time. 981 */ 982 void ima_delete_rules(void) 983 { 984 struct ima_rule_entry *entry, *tmp; 985 int i; 986 987 temp_ima_appraise = 0; 988 list_for_each_entry_safe(entry, tmp, &ima_temp_rules, list) { 989 for (i = 0; i < MAX_LSM_RULES; i++) 990 kfree(entry->lsm[i].args_p); 991 992 list_del(&entry->list); 993 kfree(entry); 994 } 995 } 996 997 #ifdef CONFIG_IMA_READ_POLICY 998 enum { 999 mask_exec = 0, mask_write, mask_read, mask_append 1000 }; 1001 1002 static const char *const mask_tokens[] = { 1003 "MAY_EXEC", 1004 "MAY_WRITE", 1005 "MAY_READ", 1006 "MAY_APPEND" 1007 }; 1008 1009 #define __ima_hook_stringify(str) (#str), 1010 1011 static const char *const func_tokens[] = { 1012 __ima_hooks(__ima_hook_stringify) 1013 }; 1014 1015 void *ima_policy_start(struct seq_file *m, loff_t *pos) 1016 { 1017 loff_t l = *pos; 1018 struct ima_rule_entry *entry; 1019 1020 rcu_read_lock(); 1021 list_for_each_entry_rcu(entry, ima_rules, list) { 1022 if (!l--) { 1023 rcu_read_unlock(); 1024 return entry; 1025 } 1026 } 1027 rcu_read_unlock(); 1028 return NULL; 1029 } 1030 1031 void *ima_policy_next(struct seq_file *m, void *v, loff_t *pos) 1032 { 1033 struct ima_rule_entry *entry = v; 1034 1035 rcu_read_lock(); 1036 entry = list_entry_rcu(entry->list.next, struct ima_rule_entry, list); 1037 rcu_read_unlock(); 1038 (*pos)++; 1039 1040 return (&entry->list == ima_rules) ? NULL : entry; 1041 } 1042 1043 void ima_policy_stop(struct seq_file *m, void *v) 1044 { 1045 } 1046 1047 #define pt(token) policy_tokens[token + Opt_err].pattern 1048 #define mt(token) mask_tokens[token] 1049 1050 /* 1051 * policy_func_show - display the ima_hooks policy rule 1052 */ 1053 static void policy_func_show(struct seq_file *m, enum ima_hooks func) 1054 { 1055 if (func > 0 && func < MAX_CHECK) 1056 seq_printf(m, "func=%s ", func_tokens[func]); 1057 else 1058 seq_printf(m, "func=%d ", func); 1059 } 1060 1061 int ima_policy_show(struct seq_file *m, void *v) 1062 { 1063 struct ima_rule_entry *entry = v; 1064 int i; 1065 char tbuf[64] = {0,}; 1066 1067 rcu_read_lock(); 1068 1069 if (entry->action & MEASURE) 1070 seq_puts(m, pt(Opt_measure)); 1071 if (entry->action & DONT_MEASURE) 1072 seq_puts(m, pt(Opt_dont_measure)); 1073 if (entry->action & APPRAISE) 1074 seq_puts(m, pt(Opt_appraise)); 1075 if (entry->action & DONT_APPRAISE) 1076 seq_puts(m, pt(Opt_dont_appraise)); 1077 if (entry->action & AUDIT) 1078 seq_puts(m, pt(Opt_audit)); 1079 if (entry->action & HASH) 1080 seq_puts(m, pt(Opt_hash)); 1081 if (entry->action & DONT_HASH) 1082 seq_puts(m, pt(Opt_dont_hash)); 1083 1084 seq_puts(m, " "); 1085 1086 if (entry->flags & IMA_FUNC) 1087 policy_func_show(m, entry->func); 1088 1089 if (entry->flags & IMA_MASK) { 1090 if (entry->mask & MAY_EXEC) 1091 seq_printf(m, pt(Opt_mask), mt(mask_exec)); 1092 if (entry->mask & MAY_WRITE) 1093 seq_printf(m, pt(Opt_mask), mt(mask_write)); 1094 if (entry->mask & MAY_READ) 1095 seq_printf(m, pt(Opt_mask), mt(mask_read)); 1096 if (entry->mask & MAY_APPEND) 1097 seq_printf(m, pt(Opt_mask), mt(mask_append)); 1098 seq_puts(m, " "); 1099 } 1100 1101 if (entry->flags & IMA_FSMAGIC) { 1102 snprintf(tbuf, sizeof(tbuf), "0x%lx", entry->fsmagic); 1103 seq_printf(m, pt(Opt_fsmagic), tbuf); 1104 seq_puts(m, " "); 1105 } 1106 1107 if (entry->flags & IMA_PCR) { 1108 snprintf(tbuf, sizeof(tbuf), "%d", entry->pcr); 1109 seq_printf(m, pt(Opt_pcr), tbuf); 1110 seq_puts(m, " "); 1111 } 1112 1113 if (entry->flags & IMA_FSUUID) { 1114 seq_printf(m, "fsuuid=%pU", &entry->fsuuid); 1115 seq_puts(m, " "); 1116 } 1117 1118 if (entry->flags & IMA_UID) { 1119 snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid)); 1120 if (entry->uid_op == &uid_gt) 1121 seq_printf(m, pt(Opt_uid_gt), tbuf); 1122 else if (entry->uid_op == &uid_lt) 1123 seq_printf(m, pt(Opt_uid_lt), tbuf); 1124 else 1125 seq_printf(m, pt(Opt_uid_eq), tbuf); 1126 seq_puts(m, " "); 1127 } 1128 1129 if (entry->flags & IMA_EUID) { 1130 snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->uid)); 1131 if (entry->uid_op == &uid_gt) 1132 seq_printf(m, pt(Opt_euid_gt), tbuf); 1133 else if (entry->uid_op == &uid_lt) 1134 seq_printf(m, pt(Opt_euid_lt), tbuf); 1135 else 1136 seq_printf(m, pt(Opt_euid_eq), tbuf); 1137 seq_puts(m, " "); 1138 } 1139 1140 if (entry->flags & IMA_FOWNER) { 1141 snprintf(tbuf, sizeof(tbuf), "%d", __kuid_val(entry->fowner)); 1142 if (entry->fowner_op == &uid_gt) 1143 seq_printf(m, pt(Opt_fowner_gt), tbuf); 1144 else if (entry->fowner_op == &uid_lt) 1145 seq_printf(m, pt(Opt_fowner_lt), tbuf); 1146 else 1147 seq_printf(m, pt(Opt_fowner_eq), tbuf); 1148 seq_puts(m, " "); 1149 } 1150 1151 for (i = 0; i < MAX_LSM_RULES; i++) { 1152 if (entry->lsm[i].rule) { 1153 switch (i) { 1154 case LSM_OBJ_USER: 1155 seq_printf(m, pt(Opt_obj_user), 1156 (char *)entry->lsm[i].args_p); 1157 break; 1158 case LSM_OBJ_ROLE: 1159 seq_printf(m, pt(Opt_obj_role), 1160 (char *)entry->lsm[i].args_p); 1161 break; 1162 case LSM_OBJ_TYPE: 1163 seq_printf(m, pt(Opt_obj_type), 1164 (char *)entry->lsm[i].args_p); 1165 break; 1166 case LSM_SUBJ_USER: 1167 seq_printf(m, pt(Opt_subj_user), 1168 (char *)entry->lsm[i].args_p); 1169 break; 1170 case LSM_SUBJ_ROLE: 1171 seq_printf(m, pt(Opt_subj_role), 1172 (char *)entry->lsm[i].args_p); 1173 break; 1174 case LSM_SUBJ_TYPE: 1175 seq_printf(m, pt(Opt_subj_type), 1176 (char *)entry->lsm[i].args_p); 1177 break; 1178 } 1179 } 1180 } 1181 if (entry->flags & IMA_DIGSIG_REQUIRED) 1182 seq_puts(m, "appraise_type=imasig "); 1183 if (entry->flags & IMA_PERMIT_DIRECTIO) 1184 seq_puts(m, "permit_directio "); 1185 rcu_read_unlock(); 1186 seq_puts(m, "\n"); 1187 return 0; 1188 } 1189 #endif /* CONFIG_IMA_READ_POLICY */ 1190