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
  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 }