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