security/integrity/ima/ima_policy.c

   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 #define IMA_INMASK      0x0040
  31 #define IMA_EUID        0x0080
  32
  33 #define UNKNOWN         0
  34 #define MEASURE         0x0001  /* same as IMA_MEASURE */
  35 #define DONT_MEASURE    0x0002
  36 #define APPRAISE        0x0004  /* same as IMA_APPRAISE */
  37 #define DONT_APPRAISE   0x0008
  38 #define AUDIT           0x0040
  39
  40 int ima_policy_flag;
  41
  42 #define MAX_LSM_RULES 6
  43 enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE,
  44         LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE
  45 };
  46
  47 enum policy_types { ORIGINAL_TCB = 1, DEFAULT_TCB };
  48
  49 struct ima_rule_entry {
  50         struct list_head list;
  51         int action;
  52         unsigned int flags;
  53         enum ima_hooks func;
  54         int mask;
  55         unsigned long fsmagic;
  56         u8 fsuuid[16];
  57         kuid_t uid;
  58         kuid_t fowner;
  59         struct {
  60                 void *rule;     /* LSM file metadata specific */
  61                 void *args_p;   /* audit value */
  62                 int type;       /* audit type */
  63         } lsm[MAX_LSM_RULES];
  64 };
  65
  66 /*
  67  * Without LSM specific knowledge, the default policy can only be
  68  * written in terms of .action, .func, .mask, .fsmagic, .uid, and .fowner
  69  */
  70
  71 /*
  72  * The minimum rule set to allow for full TCB coverage.  Measures all files
  73  * opened or mmap for exec and everything read by root.  Dangerous because
  74  * normal users can easily run the machine out of memory simply building
  75  * and running executables.
  76  */
  77 static struct ima_rule_entry dont_measure_rules[] = {
  78         {.action = DONT_MEASURE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
  79         {.action = DONT_MEASURE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
  80         {.action = DONT_MEASURE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
  81         {.action = DONT_MEASURE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
  82         {.action = DONT_MEASURE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
  83         {.action = DONT_MEASURE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
  84         {.action = DONT_MEASURE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
  85         {.action = DONT_MEASURE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
  86         {.action = DONT_MEASURE, .fsmagic = CGROUP_SUPER_MAGIC,
  87          .flags = IMA_FSMAGIC},
  88         {.action = DONT_MEASURE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC}
  89 };
  90
  91 static struct ima_rule_entry original_measurement_rules[] = {
  92         {.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
  93          .flags = IMA_FUNC | IMA_MASK},
  94         {.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
  95          .flags = IMA_FUNC | IMA_MASK},
  96         {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
  97          .uid = GLOBAL_ROOT_UID, .flags = IMA_FUNC | IMA_MASK | IMA_UID},
  98         {.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
  99         {.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
 100 };
 101
 102 static struct ima_rule_entry default_measurement_rules[] = {
 103         {.action = MEASURE, .func = MMAP_CHECK, .mask = MAY_EXEC,
 104          .flags = IMA_FUNC | IMA_MASK},
 105         {.action = MEASURE, .func = BPRM_CHECK, .mask = MAY_EXEC,
 106          .flags = IMA_FUNC | IMA_MASK},
 107         {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
 108          .uid = GLOBAL_ROOT_UID, .flags = IMA_FUNC | IMA_INMASK | IMA_EUID},
 109         {.action = MEASURE, .func = FILE_CHECK, .mask = MAY_READ,
 110          .uid = GLOBAL_ROOT_UID, .flags = IMA_FUNC | IMA_INMASK | IMA_UID},
 111         {.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
 112         {.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
 113 };
 114
 115 static struct ima_rule_entry default_appraise_rules[] = {
 116         {.action = DONT_APPRAISE, .fsmagic = PROC_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 117         {.action = DONT_APPRAISE, .fsmagic = SYSFS_MAGIC, .flags = IMA_FSMAGIC},
 118         {.action = DONT_APPRAISE, .fsmagic = DEBUGFS_MAGIC, .flags = IMA_FSMAGIC},
 119         {.action = DONT_APPRAISE, .fsmagic = TMPFS_MAGIC, .flags = IMA_FSMAGIC},
 120         {.action = DONT_APPRAISE, .fsmagic = RAMFS_MAGIC, .flags = IMA_FSMAGIC},
 121         {.action = DONT_APPRAISE, .fsmagic = DEVPTS_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 122         {.action = DONT_APPRAISE, .fsmagic = BINFMTFS_MAGIC, .flags = IMA_FSMAGIC},
 123         {.action = DONT_APPRAISE, .fsmagic = SECURITYFS_MAGIC, .flags = IMA_FSMAGIC},
 124         {.action = DONT_APPRAISE, .fsmagic = SELINUX_MAGIC, .flags = IMA_FSMAGIC},
 125         {.action = DONT_APPRAISE, .fsmagic = NSFS_MAGIC, .flags = IMA_FSMAGIC},
 126         {.action = DONT_APPRAISE, .fsmagic = CGROUP_SUPER_MAGIC, .flags = IMA_FSMAGIC},
 127 #ifndef CONFIG_IMA_APPRAISE_SIGNED_INIT
 128         {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID, .flags = IMA_FOWNER},
 129 #else
 130         /* force signature */
 131         {.action = APPRAISE, .fowner = GLOBAL_ROOT_UID,
 132          .flags = IMA_FOWNER | IMA_DIGSIG_REQUIRED},
 133 #endif
 134 };
 135
 136 static LIST_HEAD(ima_default_rules);
 137 static LIST_HEAD(ima_policy_rules);
 138 static struct list_head *ima_rules = &ima_default_rules;
 139
 140 static DEFINE_MUTEX(ima_rules_mutex);
 141
 142 static int ima_policy __initdata;
 143 static int __init default_measure_policy_setup(char *str)
 144 {
 145         if (ima_policy)
 146                 return 1;
 147
 148         ima_policy = ORIGINAL_TCB;
 149         return 1;
 150 }
 151 __setup("ima_tcb", default_measure_policy_setup);
 152
 153 static int __init policy_setup(char *str)
 154 {
 155         if (ima_policy)
 156                 return 1;
 157
 158         if (strcmp(str, "tcb") == 0)
 159                 ima_policy = DEFAULT_TCB;
 160
 161         return 1;
 162 }
 163 __setup("ima_policy=", policy_setup);
 164
 165 static bool ima_use_appraise_tcb __initdata;
 166 static int __init default_appraise_policy_setup(char *str)
 167 {
 168         ima_use_appraise_tcb = 1;
 169         return 1;
 170 }
 171 __setup("ima_appraise_tcb", default_appraise_policy_setup);
 172
 173 /*
 174  * Although the IMA policy does not change, the LSM policy can be
 175  * reloaded, leaving the IMA LSM based rules referring to the old,
 176  * stale LSM policy.
 177  *
 178  * Update the IMA LSM based rules to reflect the reloaded LSM policy.
 179  * We assume the rules still exist; and BUG_ON() if they don't.
 180  */
 181 static void ima_lsm_update_rules(void)
 182 {
 183         struct ima_rule_entry *entry, *tmp;
 184         int result;
 185         int i;
 186
 187         mutex_lock(&ima_rules_mutex);
 188         list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) {
 189                 for (i = 0; i < MAX_LSM_RULES; i++) {
 190                         if (!entry->lsm[i].rule)
 191                                 continue;
 192                         result = security_filter_rule_init(entry->lsm[i].type,
 193                                                            Audit_equal,
 194                                                            entry->lsm[i].args_p,
 195                                                            &entry->lsm[i].rule);
 196                         BUG_ON(!entry->lsm[i].rule);
 197                 }
 198         }
 199         mutex_unlock(&ima_rules_mutex);
 200 }
 201
 202 /**
 203  * ima_match_rules - determine whether an inode matches the measure rule.
 204  * @rule: a pointer to a rule
 205  * @inode: a pointer to an inode
 206  * @func: LIM hook identifier
 207  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 208  *
 209  * Returns true on rule match, false on failure.
 210  */
 211 static bool ima_match_rules(struct ima_rule_entry *rule,
 212                             struct inode *inode, enum ima_hooks func, int mask)
 213 {
 214         struct task_struct *tsk = current;
 215         const struct cred *cred = current_cred();
 216         int i;
 217
 218         if ((rule->flags & IMA_FUNC) &&
 219             (rule->func != func && func != POST_SETATTR))
 220                 return false;
 221         if ((rule->flags & IMA_MASK) &&
 222             (rule->mask != mask && func != POST_SETATTR))
 223                 return false;
 224         if ((rule->flags & IMA_INMASK) &&
 225             (!(rule->mask & mask) && func != POST_SETATTR))
 226                 return false;
 227         if ((rule->flags & IMA_FSMAGIC)
 228             && rule->fsmagic != inode->i_sb->s_magic)
 229                 return false;
 230         if ((rule->flags & IMA_FSUUID) &&
 231             memcmp(rule->fsuuid, inode->i_sb->s_uuid, sizeof(rule->fsuuid)))
 232                 return false;
 233         if ((rule->flags & IMA_UID) && !uid_eq(rule->uid, cred->uid))
 234                 return false;
 235         if (rule->flags & IMA_EUID) {
 236                 if (has_capability_noaudit(current, CAP_SETUID)) {
 237                         if (!uid_eq(rule->uid, cred->euid)
 238                             && !uid_eq(rule->uid, cred->suid)
 239                             && !uid_eq(rule->uid, cred->uid))
 240                                 return false;
 241                 } else if (!uid_eq(rule->uid, cred->euid))
 242                         return false;
 243         }
 244
 245         if ((rule->flags & IMA_FOWNER) && !uid_eq(rule->fowner, inode->i_uid))
 246                 return false;
 247         for (i = 0; i < MAX_LSM_RULES; i++) {
 248                 int rc = 0;
 249                 u32 osid, sid;
 250                 int retried = 0;
 251
 252                 if (!rule->lsm[i].rule)
 253                         continue;
 254 retry:
 255                 switch (i) {
 256                 case LSM_OBJ_USER:
 257                 case LSM_OBJ_ROLE:
 258                 case LSM_OBJ_TYPE:
 259                         security_inode_getsecid(inode, &osid);
 260                         rc = security_filter_rule_match(osid,
 261                                                         rule->lsm[i].type,
 262                                                         Audit_equal,
 263                                                         rule->lsm[i].rule,
 264                                                         NULL);
 265                         break;
 266                 case LSM_SUBJ_USER:
 267                 case LSM_SUBJ_ROLE:
 268                 case LSM_SUBJ_TYPE:
 269                         security_task_getsecid(tsk, &sid);
 270                         rc = security_filter_rule_match(sid,
 271                                                         rule->lsm[i].type,
 272                                                         Audit_equal,
 273                                                         rule->lsm[i].rule,
 274                                                         NULL);
 275                 default:
 276                         break;
 277                 }
 278                 if ((rc < 0) && (!retried)) {
 279                         retried = 1;
 280                         ima_lsm_update_rules();
 281                         goto retry;
 282                 }
 283                 if (!rc)
 284                         return false;
 285         }
 286         return true;
 287 }
 288
 289 /*
 290  * In addition to knowing that we need to appraise the file in general,
 291  * we need to differentiate between calling hooks, for hook specific rules.
 292  */
 293 static int get_subaction(struct ima_rule_entry *rule, int func)
 294 {
 295         if (!(rule->flags & IMA_FUNC))
 296                 return IMA_FILE_APPRAISE;
 297
 298         switch (func) {
 299         case MMAP_CHECK:
 300                 return IMA_MMAP_APPRAISE;
 301         case BPRM_CHECK:
 302                 return IMA_BPRM_APPRAISE;
 303         case MODULE_CHECK:
 304                 return IMA_MODULE_APPRAISE;
 305         case FIRMWARE_CHECK:
 306                 return IMA_FIRMWARE_APPRAISE;
 307         case FILE_CHECK:
 308         default:
 309                 return IMA_FILE_APPRAISE;
 310         }
 311 }
 312
 313 /**
 314  * ima_match_policy - decision based on LSM and other conditions
 315  * @inode: pointer to an inode for which the policy decision is being made
 316  * @func: IMA hook identifier
 317  * @mask: requested action (MAY_READ | MAY_WRITE | MAY_APPEND | MAY_EXEC)
 318  *
 319  * Measure decision based on func/mask/fsmagic and LSM(subj/obj/type)
 320  * conditions.
 321  *
 322  * (There is no need for locking when walking the policy list,
 323  * as elements in the list are never deleted, nor does the list
 324  * change.)
 325  */
 326 int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask,
 327                      int flags)
 328 {
 329         struct ima_rule_entry *entry;
 330         int action = 0, actmask = flags | (flags << 1);
 331
 332         list_for_each_entry(entry, ima_rules, list) {
 333
 334                 if (!(entry->action & actmask))
 335                         continue;
 336
 337                 if (!ima_match_rules(entry, inode, func, mask))
 338                         continue;
 339
 340                 action |= entry->flags & IMA_ACTION_FLAGS;
 341
 342                 action |= entry->action & IMA_DO_MASK;
 343                 if (entry->action & IMA_APPRAISE)
 344                         action |= get_subaction(entry, func);
 345
 346                 if (entry->action & IMA_DO_MASK)
 347                         actmask &= ~(entry->action | entry->action << 1);
 348                 else
 349                         actmask &= ~(entry->action | entry->action >> 1);
 350
 351                 if (!actmask)
 352                         break;
 353         }
 354
 355         return action;
 356 }
 357
 358 /*
 359  * Initialize the ima_policy_flag variable based on the currently
 360  * loaded policy.  Based on this flag, the decision to short circuit
 361  * out of a function or not call the function in the first place
 362  * can be made earlier.
 363  */
 364 void ima_update_policy_flag(void)
 365 {
 366         struct ima_rule_entry *entry;
 367
 368         ima_policy_flag = 0;
 369         list_for_each_entry(entry, ima_rules, list) {
 370                 if (entry->action & IMA_DO_MASK)
 371                         ima_policy_flag |= entry->action;
 372         }
 373
 374         if (!ima_appraise)
 375                 ima_policy_flag &= ~IMA_APPRAISE;
 376 }
 377
 378 /**
 379  * ima_init_policy - initialize the default measure rules.
 380  *
 381  * ima_rules points to either the ima_default_rules or the
 382  * the new ima_policy_rules.
 383  */
 384 void __init ima_init_policy(void)
 385 {
 386         int i, measure_entries, appraise_entries;
 387
 388         /* if !ima_policy set entries = 0 so we load NO default rules */
 389         measure_entries = ima_policy ? ARRAY_SIZE(dont_measure_rules) : 0;
 390         appraise_entries = ima_use_appraise_tcb ?
 391                          ARRAY_SIZE(default_appraise_rules) : 0;
 392
 393         for (i = 0; i < measure_entries; i++)
 394                 list_add_tail(&dont_measure_rules[i].list, &ima_default_rules);
 395
 396         switch (ima_policy) {
 397         case ORIGINAL_TCB:
 398                 for (i = 0; i < ARRAY_SIZE(original_measurement_rules); i++)
 399                         list_add_tail(&original_measurement_rules[i].list,
 400                                       &ima_default_rules);
 401                 break;
 402         case DEFAULT_TCB:
 403                 for (i = 0; i < ARRAY_SIZE(default_measurement_rules); i++)
 404                         list_add_tail(&default_measurement_rules[i].list,
 405                                       &ima_default_rules);
 406         default:
 407                 break;
 408         }
 409
 410         for (i = 0; i < appraise_entries; i++) {
 411                 list_add_tail(&default_appraise_rules[i].list,
 412                               &ima_default_rules);
 413         }
 414
 415 }
 416
 417 /**
 418  * ima_update_policy - update default_rules with new measure rules
 419  *
 420  * Called on file .release to update the default rules with a complete new
 421  * policy.  Once updated, the policy is locked, no additional rules can be
 422  * added to the policy.
 423  */
 424 void ima_update_policy(void)
 425 {
 426         ima_rules = &ima_policy_rules;
 427         ima_update_policy_flag();
 428 }
 429
 430 enum {
 431         Opt_err = -1,
 432         Opt_measure = 1, Opt_dont_measure,
 433         Opt_appraise, Opt_dont_appraise,
 434         Opt_audit,
 435         Opt_obj_user, Opt_obj_role, Opt_obj_type,
 436         Opt_subj_user, Opt_subj_role, Opt_subj_type,
 437         Opt_func, Opt_mask, Opt_fsmagic,
 438         Opt_uid, Opt_euid, Opt_fowner,
 439         Opt_appraise_type, Opt_fsuuid, Opt_permit_directio
 440 };
 441
 442 static match_table_t policy_tokens = {
 443         {Opt_measure, "measure"},
 444         {Opt_dont_measure, "dont_measure"},
 445         {Opt_appraise, "appraise"},
 446         {Opt_dont_appraise, "dont_appraise"},
 447         {Opt_audit, "audit"},
 448         {Opt_obj_user, "obj_user=%s"},
 449         {Opt_obj_role, "obj_role=%s"},
 450         {Opt_obj_type, "obj_type=%s"},
 451         {Opt_subj_user, "subj_user=%s"},
 452         {Opt_subj_role, "subj_role=%s"},
 453         {Opt_subj_type, "subj_type=%s"},
 454         {Opt_func, "func=%s"},
 455         {Opt_mask, "mask=%s"},
 456         {Opt_fsmagic, "fsmagic=%s"},
 457         {Opt_fsuuid, "fsuuid=%s"},
 458         {Opt_uid, "uid=%s"},
 459         {Opt_euid, "euid=%s"},
 460         {Opt_fowner, "fowner=%s"},
 461         {Opt_appraise_type, "appraise_type=%s"},
 462         {Opt_permit_directio, "permit_directio"},
 463         {Opt_err, NULL}
 464 };
 465
 466 static int ima_lsm_rule_init(struct ima_rule_entry *entry,
 467                              substring_t *args, int lsm_rule, int audit_type)
 468 {
 469         int result;
 470
 471         if (entry->lsm[lsm_rule].rule)
 472                 return -EINVAL;
 473
 474         entry->lsm[lsm_rule].args_p = match_strdup(args);
 475         if (!entry->lsm[lsm_rule].args_p)
 476                 return -ENOMEM;
 477
 478         entry->lsm[lsm_rule].type = audit_type;
 479         result = security_filter_rule_init(entry->lsm[lsm_rule].type,
 480                                            Audit_equal,
 481                                            entry->lsm[lsm_rule].args_p,
 482                                            &entry->lsm[lsm_rule].rule);
 483         if (!entry->lsm[lsm_rule].rule) {
 484                 kfree(entry->lsm[lsm_rule].args_p);
 485                 return -EINVAL;
 486         }
 487
 488         return result;
 489 }
 490
 491 static void ima_log_string(struct audit_buffer *ab, char *key, char *value)
 492 {
 493         audit_log_format(ab, "%s=", key);
 494         audit_log_untrustedstring(ab, value);
 495         audit_log_format(ab, " ");
 496 }
 497
 498 static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
 499 {
 500         struct audit_buffer *ab;
 501         char *from;
 502         char *p;
 503         int result = 0;
 504
 505         ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_RULE);
 506
 507         entry->uid = INVALID_UID;
 508         entry->fowner = INVALID_UID;
 509         entry->action = UNKNOWN;
 510         while ((p = strsep(&rule, " \t")) != NULL) {
 511                 substring_t args[MAX_OPT_ARGS];
 512                 int token;
 513                 unsigned long lnum;
 514
 515                 if (result < 0)
 516                         break;
 517                 if ((*p == '\0') || (*p == ' ') || (*p == '\t'))
 518                         continue;
 519                 token = match_token(p, policy_tokens, args);
 520                 switch (token) {
 521                 case Opt_measure:
 522                         ima_log_string(ab, "action", "measure");
 523
 524                         if (entry->action != UNKNOWN)
 525                                 result = -EINVAL;
 526
 527                         entry->action = MEASURE;
 528                         break;
 529                 case Opt_dont_measure:
 530                         ima_log_string(ab, "action", "dont_measure");
 531
 532                         if (entry->action != UNKNOWN)
 533                                 result = -EINVAL;
 534
 535                         entry->action = DONT_MEASURE;
 536                         break;
 537                 case Opt_appraise:
 538                         ima_log_string(ab, "action", "appraise");
 539
 540                         if (entry->action != UNKNOWN)
 541                                 result = -EINVAL;
 542
 543                         entry->action = APPRAISE;
 544                         break;
 545                 case Opt_dont_appraise:
 546                         ima_log_string(ab, "action", "dont_appraise");
 547
 548                         if (entry->action != UNKNOWN)
 549                                 result = -EINVAL;
 550
 551                         entry->action = DONT_APPRAISE;
 552                         break;
 553                 case Opt_audit:
 554                         ima_log_string(ab, "action", "audit");
 555
 556                         if (entry->action != UNKNOWN)
 557                                 result = -EINVAL;
 558
 559                         entry->action = AUDIT;
 560                         break;
 561                 case Opt_func:
 562                         ima_log_string(ab, "func", args[0].from);
 563
 564                         if (entry->func)
 565                                 result = -EINVAL;
 566
 567                         if (strcmp(args[0].from, "FILE_CHECK") == 0)
 568                                 entry->func = FILE_CHECK;
 569                         /* PATH_CHECK is for backwards compat */
 570                         else if (strcmp(args[0].from, "PATH_CHECK") == 0)
 571                                 entry->func = FILE_CHECK;
 572                         else if (strcmp(args[0].from, "MODULE_CHECK") == 0)
 573                                 entry->func = MODULE_CHECK;
 574                         else if (strcmp(args[0].from, "FIRMWARE_CHECK") == 0)
 575                                 entry->func = FIRMWARE_CHECK;
 576                         else if ((strcmp(args[0].from, "FILE_MMAP") == 0)
 577                                 || (strcmp(args[0].from, "MMAP_CHECK") == 0))
 578                                 entry->func = MMAP_CHECK;
 579                         else if (strcmp(args[0].from, "BPRM_CHECK") == 0)
 580                                 entry->func = BPRM_CHECK;
 581                         else
 582                                 result = -EINVAL;
 583                         if (!result)
 584                                 entry->flags |= IMA_FUNC;
 585                         break;
 586                 case Opt_mask:
 587                         ima_log_string(ab, "mask", args[0].from);
 588
 589                         if (entry->mask)
 590                                 result = -EINVAL;
 591
 592                         from = args[0].from;
 593                         if (*from == '^')
 594                                 from++;
 595
 596                         if ((strcmp(from, "MAY_EXEC")) == 0)
 597                                 entry->mask = MAY_EXEC;
 598                         else if (strcmp(from, "MAY_WRITE") == 0)
 599                                 entry->mask = MAY_WRITE;
 600                         else if (strcmp(from, "MAY_READ") == 0)
 601                                 entry->mask = MAY_READ;
 602                         else if (strcmp(from, "MAY_APPEND") == 0)
 603                                 entry->mask = MAY_APPEND;
 604                         else
 605                                 result = -EINVAL;
 606                         if (!result)
 607                                 entry->flags |= (*args[0].from == '^')
 608                                      ? IMA_INMASK : IMA_MASK;
 609                         break;
 610                 case Opt_fsmagic:
 611                         ima_log_string(ab, "fsmagic", args[0].from);
 612
 613                         if (entry->fsmagic) {
 614                                 result = -EINVAL;
 615                                 break;
 616                         }
 617
 618                         result = kstrtoul(args[0].from, 16, &entry->fsmagic);
 619                         if (!result)
 620                                 entry->flags |= IMA_FSMAGIC;
 621                         break;
 622                 case Opt_fsuuid:
 623                         ima_log_string(ab, "fsuuid", args[0].from);
 624
 625                         if (memchr_inv(entry->fsuuid, 0x00,
 626                                        sizeof(entry->fsuuid))) {
 627                                 result = -EINVAL;
 628                                 break;
 629                         }
 630
 631                         result = blk_part_pack_uuid(args[0].from,
 632                                                     entry->fsuuid);
 633                         if (!result)
 634                                 entry->flags |= IMA_FSUUID;
 635                         break;
 636                 case Opt_uid:
 637                         ima_log_string(ab, "uid", args[0].from);
 638                 case Opt_euid:
 639                         if (token == Opt_euid)
 640                                 ima_log_string(ab, "euid", args[0].from);
 641
 642                         if (uid_valid(entry->uid)) {
 643                                 result = -EINVAL;
 644                                 break;
 645                         }
 646
 647                         result = kstrtoul(args[0].from, 10, &lnum);
 648                         if (!result) {
 649                                 entry->uid = make_kuid(current_user_ns(),
 650                                                        (uid_t) lnum);
 651                                 if (!uid_valid(entry->uid) ||
 652                                     (uid_t)lnum != lnum)
 653                                         result = -EINVAL;
 654                                 else
 655                                         entry->flags |= (token == Opt_uid)
 656                                             ? IMA_UID : IMA_EUID;
 657                         }
 658                         break;
 659                 case Opt_fowner:
 660                         ima_log_string(ab, "fowner", args[0].from);
 661
 662                         if (uid_valid(entry->fowner)) {
 663                                 result = -EINVAL;
 664                                 break;
 665                         }
 666
 667                         result = kstrtoul(args[0].from, 10, &lnum);
 668                         if (!result) {
 669                                 entry->fowner = make_kuid(current_user_ns(), (uid_t)lnum);
 670                                 if (!uid_valid(entry->fowner) || (((uid_t)lnum) != lnum))
 671                                         result = -EINVAL;
 672                                 else
 673                                         entry->flags |= IMA_FOWNER;
 674                         }
 675                         break;
 676                 case Opt_obj_user:
 677                         ima_log_string(ab, "obj_user", args[0].from);
 678                         result = ima_lsm_rule_init(entry, args,
 679                                                    LSM_OBJ_USER,
 680                                                    AUDIT_OBJ_USER);
 681                         break;
 682                 case Opt_obj_role:
 683                         ima_log_string(ab, "obj_role", args[0].from);
 684                         result = ima_lsm_rule_init(entry, args,
 685                                                    LSM_OBJ_ROLE,
 686                                                    AUDIT_OBJ_ROLE);
 687                         break;
 688                 case Opt_obj_type:
 689                         ima_log_string(ab, "obj_type", args[0].from);
 690                         result = ima_lsm_rule_init(entry, args,
 691                                                    LSM_OBJ_TYPE,
 692                                                    AUDIT_OBJ_TYPE);
 693                         break;
 694                 case Opt_subj_user:
 695                         ima_log_string(ab, "subj_user", args[0].from);
 696                         result = ima_lsm_rule_init(entry, args,
 697                                                    LSM_SUBJ_USER,
 698                                                    AUDIT_SUBJ_USER);
 699                         break;
 700                 case Opt_subj_role:
 701                         ima_log_string(ab, "subj_role", args[0].from);
 702                         result = ima_lsm_rule_init(entry, args,
 703                                                    LSM_SUBJ_ROLE,
 704                                                    AUDIT_SUBJ_ROLE);
 705                         break;
 706                 case Opt_subj_type:
 707                         ima_log_string(ab, "subj_type", args[0].from);
 708                         result = ima_lsm_rule_init(entry, args,
 709                                                    LSM_SUBJ_TYPE,
 710                                                    AUDIT_SUBJ_TYPE);
 711                         break;
 712                 case Opt_appraise_type:
 713                         if (entry->action != APPRAISE) {
 714                                 result = -EINVAL;
 715                                 break;
 716                         }
 717
 718                         ima_log_string(ab, "appraise_type", args[0].from);
 719                         if ((strcmp(args[0].from, "imasig")) == 0)
 720                                 entry->flags |= IMA_DIGSIG_REQUIRED;
 721                         else
 722                                 result = -EINVAL;
 723                         break;
 724                 case Opt_permit_directio:
 725                         entry->flags |= IMA_PERMIT_DIRECTIO;
 726                         break;
 727                 case Opt_err:
 728                         ima_log_string(ab, "UNKNOWN", p);
 729                         result = -EINVAL;
 730                         break;
 731                 }
 732         }
 733         if (!result && (entry->action == UNKNOWN))
 734                 result = -EINVAL;
 735         else if (entry->func == MODULE_CHECK)
 736                 ima_appraise |= IMA_APPRAISE_MODULES;
 737         else if (entry->func == FIRMWARE_CHECK)
 738                 ima_appraise |= IMA_APPRAISE_FIRMWARE;
 739         audit_log_format(ab, "res=%d", !result);
 740         audit_log_end(ab);
 741         return result;
 742 }
 743
 744 /**
 745  * ima_parse_add_rule - add a rule to ima_policy_rules
 746  * @rule - ima measurement policy rule
 747  *
 748  * Uses a mutex to protect the policy list from multiple concurrent writers.
 749  * Returns the length of the rule parsed, an error code on failure
 750  */
 751 ssize_t ima_parse_add_rule(char *rule)
 752 {
 753         static const char op[] = "update_policy";
 754         char *p;
 755         struct ima_rule_entry *entry;
 756         ssize_t result, len;
 757         int audit_info = 0;
 758
 759         p = strsep(&rule, "\n");
 760         len = strlen(p) + 1;
 761         p += strspn(p, " \t");
 762
 763         if (*p == '#' || *p == '\0')
 764                 return len;
 765
 766         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 767         if (!entry) {
 768                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
 769                                     NULL, op, "-ENOMEM", -ENOMEM, audit_info);
 770                 return -ENOMEM;
 771         }
 772
 773         INIT_LIST_HEAD(&entry->list);
 774
 775         result = ima_parse_rule(p, entry);
 776         if (result) {
 777                 kfree(entry);
 778                 integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL,
 779                                     NULL, op, "invalid-policy", result,
 780                                     audit_info);
 781                 return result;
 782         }
 783
 784         mutex_lock(&ima_rules_mutex);
 785         list_add_tail(&entry->list, &ima_policy_rules);
 786         mutex_unlock(&ima_rules_mutex);
 787
 788         return len;
 789 }
 790
 791 /* ima_delete_rules called to cleanup invalid policy */
 792 void ima_delete_rules(void)
 793 {
 794         struct ima_rule_entry *entry, *tmp;
 795         int i;
 796
 797         mutex_lock(&ima_rules_mutex);
 798         list_for_each_entry_safe(entry, tmp, &ima_policy_rules, list) {
 799                 for (i = 0; i < MAX_LSM_RULES; i++)
 800                         kfree(entry->lsm[i].args_p);
 801
 802                 list_del(&entry->list);
 803                 kfree(entry);
 804         }
 805         mutex_unlock(&ima_rules_mutex);
 806 }